EPS Training
description
Transcript of EPS Training
Course Outline
1. Data preparation workflow
using PanWizard.
2. Data preparation – large file.
3. Analysis methods and workflow.
Quick Match.
4. Faults and boundaries.
5. Dual porosity reservoir.
6. Closed reservoir.
7. Parallel faults.
Phase redistribuion.
8. Horizontal well.
9. Partial completion.
10. Radial composite reservoir.
11. Hydraulically fractured well.
12. Gas welltesting - flow-after-flow test.
13. Gas welltesting – isochronal test.
14. Advanced Simulation.
15. Test design.
16. Interference test design and analysis.
17. Reporting.
18. Slug test analysis
0. Gauge data – reservoir data
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Edinburgh Petroleum Services PanSystem User Course
Gauge data Gauge data -- reservoir datareservoir data
2
1 2
1
2
162.6log log 3.2275 0.86859
162.6
log 3.2275 0.86859
1.1513 log 3.2275
i wf
t w
t hr i
t w
t hr i
t w
qB kp p t S
kh c r
qBm kh k
kh
kp p m S
c r
p p kS
m c r
S from intercept
at t =1 hr
kh from slope of line
Pressure Drawdown Theory for an Infinite
Acting Reservoir with an Altered Zone
Radial flow, homogeneous reservoir
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To analyse the welltest we need accurate To analyse the welltest we need accurate
measurements of:measurements of:
–– TimeTime
–– FlowrateFlowrate
–– PressurePressure
–– Reservoir and fluid parametersReservoir and fluid parameters
–– (Temperature)(Temperature)
TimeTime
TimeTime
Taken for granted that this is errorTaken for granted that this is error--free (quartz free (quartz
gauge clocks)gauge clocks)
Surface rate changes (from testing report) must be Surface rate changes (from testing report) must be
synchronised with downhole gauge clocksynchronised with downhole gauge clock
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FlowrateFlowrate
FlowrateFlowrate
Theory has been developed for Theory has been developed for sandfacesandface flowrateflowrate
We normally measure surface flowrateWe normally measure surface flowrate–– How accurate?How accurate?
–– Must convert to downhole* conditions (volume factors)Must convert to downhole* conditions (volume factors)
** ““DownholeDownhole”” means reservoir (not sandface) P and Tmeans reservoir (not sandface) P and T
Error in flowrate means error in analysisError in flowrate means error in analysis–– sometimes discrepancies between test analyses at different ratessometimes discrepancies between test analyses at different rates
owing to +/owing to +/-- measurement errors measurement errors
PressurePressure
PressurePressureCorrect reading requires accurate temperature and valid Correct reading requires accurate temperature and valid
calibrationcalibration
Theory has been developed for Theory has been developed for sandfacesandface pressurepressure
The gauge is rarely at the sandfaceThe gauge is rarely at the sandface
So we donSo we don’’t measure sandface pressure, we measure t measure sandface pressure, we measure
gauge depth pressuregauge depth pressure
Gauge position is very important Gauge position is very important –– make sure you know make sure you know
where it iswhere it is……....
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P1
Gauge depthGauge depth
Gauge reading depends on Gauge reading depends on
pressure difference between pressure difference between
midmid--perfperf and gauge position:and gauge position:
–– Hydrostatic pressure gradientHydrostatic pressure gradient
–– Friction pressure gradient.Friction pressure gradient.
A second gauge can provide a A second gauge can provide a
useful insight.useful insight.
P2
Hydrostatic Hydrostatic pp
HydrostaticHydrostatic
–– need to know fluid density and angle of deviationneed to know fluid density and angle of deviation
–– single phase is relatively easysingle phase is relatively easy
–– multiphase is more difficultmultiphase is more difficult
–– Flowing: Flowing: –– use WellFlo, Prosper, etcuse WellFlo, Prosper, etc
–– ShutShut--in: in: –– problem of phase segregation, liquid fallback, problem of phase segregation, liquid fallback,
difficult to quantifydifficult to quantify
–– pp11 may change with time, even during the test. may change with time, even during the test.
(You might not even know this is happening!)(You might not even know this is happening!)
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Hydrostatic Hydrostatic pp
Wellbore cleanWellbore clean--upup
–– pp11 changes during the DST, especially at the beginningchanges during the DST, especially at the beginning
–– important if comparing initial buildup p* with final p* to important if comparing initial buildup p* with final p* to
check for depletion check for depletion –– observed difference could be due observed difference could be due
to hydrostatic changeto hydrostatic change
Gas welltest at different flowratesGas welltest at different flowrates
–– different bhfp for each rate means different gas density different bhfp for each rate means different gas density
–– may or may not be importantmay or may not be important
–– condensate with different condensate with different bhfpbhfp’’ss below dew point will below dew point will
have different liquid fractionshave different liquid fractions
–– less of a problem (ie: ignored) for oil welltestsless of a problem (ie: ignored) for oil welltests
–– a second gauge can give a second gauge can give
useful information about useful information about
changes in fluid density at changes in fluid density at
the gauges:the gauges:
–– but gauge calibration but gauge calibration
errors make errors make PP1212 of semiof semi--
quantitative use only.quantitative use only.
P1
P12
fluid= ( P12 / z12) psi/ft
0.4335
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FrictionFriction pp
FrictionFriction
–– will vary with flowratewill vary with flowrate
–– usually negligible unless long distances and usually negligible unless long distances and
high rates are involvedhigh rates are involved
–– check using WellFlo, Prosper, etc to see if it check using WellFlo, Prosper, etc to see if it
might be significantmight be significant
–– if significant and not corrected out, it will if significant and not corrected out, it will
appear in the analysis as an appear in the analysis as an increased skin increased skin
factorfactor (see Slide #2). This may appear as a (see Slide #2). This may appear as a
raterate--dependent skin (D) in a multidependent skin (D) in a multi--rate test.rate test.
IfIf pp11 can be assumed constantcan be assumed constant
–– the only problem is to estimate itthe only problem is to estimate it……..
IfIf pp11 is changing with timeis changing with time
–– the changes may all occur during the early the changes may all occur during the early
part of the test (eg: liquid fallback at the start part of the test (eg: liquid fallback at the start
of a shutof a shut--in) and can be considered as part of in) and can be considered as part of
the wellbore storage period.the wellbore storage period.
–– if they continue throughout the test, you have if they continue throughout the test, you have
a more serious problema more serious problem……....
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Slopes and absolutesSlopes and absolutes
Analysis involving Analysis involving slopesslopes and and derivativesderivatives is not is not
affected by affected by pp11 as long as it is a constant shift.as long as it is a constant shift.
Analyses of Analyses of absolutesabsolutes (final shut(final shut--in pressure, in pressure,
extrapolated pressure, bhfp) should all be extrapolated pressure, bhfp) should all be
corrected to midcorrected to mid--perfperf and, eventually, to any and, eventually, to any
other reference datum depthother reference datum depth
If gauge depth is not known, specify in your If gauge depth is not known, specify in your
report that all pressures are at gauge depth.report that all pressures are at gauge depth.
The theoryThe theory
The radial flow equation on Slide #2 was derived from first The radial flow equation on Slide #2 was derived from first
principles by making several simplifying assumptions to arrive aprinciples by making several simplifying assumptions to arrive att
a workable equation with (pa workable equation with (pii--ppwfwf)) log log tt::
–– homogeneous reservoir, uniform thickness, fully homogeneous reservoir, uniform thickness, fully perfperf’’dd
–– tt greater than a certain minimum value for the greater than a certain minimum value for the ““semilogsemilog
approximationapproximation”” to be validto be valid
–– constant fluid properties (FVF, constant fluid properties (FVF, µµ,, ))
–– small, constant compressibility (Csmall, constant compressibility (Ctt))
Last two are satisfied by water, and heavy to medium oils.Last two are satisfied by water, and heavy to medium oils.
But not gas. Constant property approach must be used with a But not gas. Constant property approach must be used with a
pressure function pressure function –– ““real gas pseudoreal gas pseudo--pressurepressure””..
Volatile oils and condensates Volatile oils and condensates –– useuse ““multiphase pseudomultiphase pseudo--
pressurepressure””..
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What Permeability?What Permeability?
Slope analysis in radial flow gives usSlope analysis in radial flow gives us
kh/kh/µµ (transmissibility):(transmissibility):
–– value of k derived depends on what you put in value of k derived depends on what you put in
for for µµ and and hh
–– gross hgross h gives gives gross kgross k,, net hnet h gives gives net knet k,, wrongwrong
hh givesgives wrong kwrong k
–– in a multiin a multi--layered reservoir you will usually get layered reservoir you will usually get
thicknessthickness--averagedaveraged
k = kjhj / hj
Stratified Reservoir
q
pepe
q1
q2
q3
pw
k1, h1
k2, h2
k3, h3
No reservoir communication1
n
total j jkh k h
htotal
P
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Layered Systemq
pepe
q1
q2
q3
pw
k1, h1
k2, h2
k3, h3
Reservoir communication1
n
total j jkh k h
htotal
…depending on a number of factorsP
ExampleExample
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Lower gauge
Upper gauge
Well shut in
1.71 psi 2.42 psi
2.04 psi
1.62 psi
Difference
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Upper gauge
Lower gauge
Mid-perf
Diff P
Correction PWater
Oil
Gas
x
~9 psi
~16 psi
xa
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Example 1
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EX 1.1Example 1Example 1-- Part IPart I
Data Preparation
WorkFlow
Using
PanWizardPanWizard
Part IPart I
EX 1.2OverviewOverview
• This example uses various features of the DATAPREP
section in PanSystem and focuses mainly on how to get
the data in an analysable stage
• PanWizard has been designed to simplify the input of
data necessary for analysis of a simple welltest
• This is a gas well example, incorporating an initial flow
initial build-up, a flow-after-flow (FAF) test and a final
build-up
Example 1
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EX 1.3PanWizard
• Starting a New file
-Click on Next >>
• Loading an available file
-Click on Load PAN file
EX 1.4Data PreparationData Preparation
Example 1
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EX 1.5Data PreparationData Preparation
Dry gas reservoirs
Use Condensate fluid type for
Wet gas reservoirs (Pres>Pdew)
Select Condensate fluid type
and Tick Multiphase option
for Gas condensate reservoirs
(Pres<Pdew)
Use Multiphase Pseudo-
Pressure Method when more
than one phase are moving
inside the reservoir.
EX 1.6Data PreparationData Preparation
Example 1
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EX 1.7Data PreparationData Preparation
EX 1.8Data PreparationData Preparation
Example 1
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EX 1.9Data PreparationData Preparation
EX 1.10Data PreparationData Preparation
Example 1
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EX 1.11Data PreparationData Preparation
EX 1.12Data PreparationData Preparation
Example 1
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EX 1.13Data PreparationData Preparation
EX 1.14Data PreparationData Preparation
• Click Calculate all button
• Click OK
• Click Quit in PanWizard Dialog Box
-keep all the entered data
• File - Save As … - Example01
Example 1
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EX 1.1Example 1Example 1-- Part IIPart II
Data Preparation
WorkFlow
Using
PanWizardPanWizard
Part IIPart II
EX 1.2OverviewOverview• Normally the gauge data are provided as electronic
files.
• There may be more than one gauge.
• Type of the gauge
-Gauge Accuracy
-Gauge Drift
-Gauge Resolution
-Gauge Histerices
Example 1
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EX 1.3PanWizard
• Load PAN file
-Example01
EX 1.4Data PreparationData Preparation• PanWizard - What next ?
Example 1
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EX 1.5Data PreparationData Preparation
• Click on Import… button and open Test1.dat file
EX 1.6Data PreparationData Preparation
Example 1
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EX 1.7Data PreparationData Preparation
EX 1.8Data PreparationData Preparation
Example 1
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EX 1.9Data PreparationData Preparation
EX 1.10Data PreparationData Preparation
• Click on Example button
Example 1
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EX 1.11Data PreparationData Preparation
EX 1.12Data PreparationData Preparation
Example 1
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EX 1.13Data PreparationData PreparationFor this example the test rates are as follows:
Time, hrs Rate, MMscf/d Comment
0.0 0.0 Setting the gauge
5.66 0.0 Start Cleaning-up
8.67 12.25 End Cleaning-up
11.73 0.0 End 1st PBU
18.85 3.95 End 1st Flow Period
26.31 6.60 End 2nd Flow Period
32.34 9.00 End 3rd Flow Period
37.77 12.11 End 4th Flow Period
61.56 0.0 End Final PBU
EX 1.14Data PreparationData Preparation
Example 1
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EX 1.15Data PreparationData Preparation
EX 1.16Data PreparationData Preparation
Click on the Quit
button and keep
all the data.
Example 1
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EX 1.17Data PreparationData Preparation
• Import Test2.tpr and
Test3.tpr
• Note that these files include
one gauge data which has
been split into two files.
• So append Test3.tpr to
Test2.tpr by ticking Append
to file option.
EX 1.18Data PreparationData PreparationShifting Gauge Data:
• Plot both pressure records, test1 and test2.
• Click on Shift button
Shifting data horizontally
by constant time value
Shifting data vertically by
constant signal value
Draw a box before using
the Shift button
Example 1
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EX 1.19Data PreparationData Preparation
The two data sets (Test1 and Test2) are
displaced in time.
• Shift Test2 pressure data
– Use Shift button
– Use Zoom to improve resolution
• When satisfied with shift...
– Make a note of Delta-t (at the bottom of the
screen)
– Click Difference button
• Use Shift and Difference until you get a good
time match
EX 1.20Data PreparationData PreparationRate Change definition buttons when more than one data file is
available:
TEST2 data file is chosen
to plot
TEST1 is the Master data
file
If we click on Plot button, the rate change buttons
are not active any more.
The Rate Change buttons are Active ONLY if the Master file is plotted
Example 1
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EX 1.21
There are three icons on the Dataprep tool bar
used for copying data:
• Copy & Paste Including Time (patch
section from another data file)
• Copy, Resample & Paste (patch column
from another data file)
• Resample column from one data file to
create a new column in another
• The Master file is always the destination
for copying
Data PreparationData Preparation
EX 1.22Data PreparationData Preparation• Copy & Paste Including Time (patch section from another data
file)
File 1 (Master data file) File 2
Time Pressure Time Pressure
1.0 4000 1.2 3999
1.5 3995 1.3 3997
. . . .
. . . .
. . . .
} {
File 1 (new)
Time Pressure
1.0 4000
1.2 3999
1.3 3997
1.5 3995
. .
. .
Example 1
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EX 1.23
• Copy, Resample & Paste (patch column from another data file)
Data PreparationData Preparation
File 1 (Master data file) File 2
Time Pressure Time Pressure
1.0 4000 1.2 3999
1.25 4150 1.3 3997
1.5 3995 . .
. . . .
. . . .
} {
File 1 (new)
Time Pressure
1.0 4000
1.25 3998
1.5 3995
. .
. .
EX 1.24Data PreparationData Preparation
File 1 (Master data file) File 2
Time Pressure Time Pressure
1.0 4000 0.9 4000
1.25 3998 1.3 3997
1.5 3995 1.7 3990
. . . .
. . . .
} {
File 1 (new)
Time Pressure 1 Pressure 2
1.0 4000 3999.25
1.25 3998 3996.62
1.5 3995 3993.50
. . .
. . .
• Resample column from one data file to create a new column in another
Example 1
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EX 1.25
END OF EXAMPLE 1
Data PreparationData Preparation
Example 2
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EX 2.1Example 2Example 2
Data Preparation:
Large Data Files
EX 2.2DataPrep OverviewDataPrep Overview• Import data file
• Delete data at start and end
• Confirm deletions
• Define flow periods
• Reduce number of data points of each test period
• Confirm reductions
• Define Well, Layer and Fluid Parameters
Example 2
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EX 2.3DataPrepDataPrep--ImportImport
• Start PanSystem: File - New
• Dataprep - Well and Reservoir Description
– Select Oil as reservoir fluid (Default)
• Config - Units
– Select OILFABS in Units System (Default)
• DataPrep - Gauge Data - Import
– Example02.tpr
– Review File format
EX 2.4View Gauge DataView Gauge Data
Example 2
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EX 2.5View Gauge DataView Gauge Data
PanSystem will specify the
columns automatically
The user should define each column
Should be used to import Date column.(Time column format must be (DATE)hh:mm:ss)
EX 2.6DataPrepDataPrep
• Note data column format /units:
• Column 1: Time in decimal hours
• Column 2: Pressure in psia
• Column 3: Temperature in oF.
• Click Import
• Data import should take a matter of seconds
• To plot the imported data highlight the dataset of interest
from the Data File/Column List
• Click on Add to List icon and then Plot
Example 2
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EX 2.7Viewing Imported DataViewing Imported Data
EX 2.8DataprepDataprep• Plot the pressure column only
• Delete data at start and end i.e. during running in and
pulling out
• Confirm deletions
– Draw box around data at start and end of the test
and hit Delete toolbar icon
– Confirm deletion to minimise plotting time
– Check with the Number toolbar button.
– There should now be approximately 25,000 data
points remaining
– Save file as Example02.PAN
Example 2
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EX 2.9DataprepDataprep
EX 2.10DataprepDataprep
• Comments on all flow periods
• Delete all points up to just before the
fourth Buildup
• Delete the data points at the end of the
test
• Confirm deletions
• There will be around 8400 points
Example 2
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EX 2.11DataprepDataprep
EX 2.12DataprepDataprep
Define the flow periods:
• Zoom-in on the beginning of the last drawdown
• Select the ‘Nearest data point’ option and define the
beginning of the drawdown then Zoom-out
• Zoom-in on the beginning of the Buildup period and
use the ‘Exact point’ option to define the start of the
build-up (very noisy data)
• Enter the rate as 400 bbl/day then zoom-out
• Zoom-in on the end of the buildup period and use
the ‘Nearest data point’ option to define the end of
the buildup then zoom-out
Example 2
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EX 2.13Data ReductionData Reduction
Select:
– Whole test (no selection)
– Box
– Test period
– Click Data Reduction Button
Methods of Reduction
Signal column which will
be reduced
Name of new Reduced Data file.
PS does keep the original file just in case.
EX 2.14Data SmoothingData Smoothing
Data Smoothing• Select
– Whole test (no selection)
– Box
– Test period
– Click Data Smoothing Button
Determines the number of points
to be used for smoothing
Define how to select the points
Define how to weight each point
Example 2
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EX 2.15Data SmoothingData Smoothing
Select the data column that you
would like to smooth
Define the name of smoothed
output data column (default is
SM1 Pressure #2 )
PS does keep the original file just in case
EX 2.16Data ReductionData Reduction• Select the drawdown period on the ruler bar
• Click on ‘Data Reduction and Smoothing facility’
button and
– Reduce to 200 points per log cycle
– Smooth with 0.1 window span
– this should leave about 430 data points
• Select the final build-up on the ruler bar
– Reduce the build-up data again using 200 points per log cycle
– Smooth with 0.1 window span
– This should leave approximately 370 data points
• Highlight any extra erroneous points and delete by
clicking the trash icon and Confirm deletions
• Save file
Example 2
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EX 2.17DataprepDataprep
EX 2.18DataprepDataprep
• Go to Dataprep
- Well and Reservoir Description (Analytical)...
• Enter the following data in well, layer and fluid
parameters screens
– Rw = 0.35 ft.
– h = 87 ft.
– Ø = 0.17
– Bo = 1.12 resbbl/STB
– oil = 0.7 cp
– Ct = 5.2E-5 psi-1
• Click OK
• Save File
Example 2
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EX 2.19AnalysisAnalysis
• Select Analysis - Plot
• Select Build-up on the ruler bar
• Select Log/Log Plot icon
Note that in the early time region the
pressure and derivative data should
follow unit slope trend and overlay
each other. If not the BU start time
and pressure have not been defined
properly.
• Adjust T0 to find a ‘good’ value
• T0 = 78.186 Hours.
EX 2.20LogLog--Log PlotLog Plot
Example 2
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EX 2.21Example 2Example 2
END OF EXAMPLE 2
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Example 3
Example 3Example 3
Analysis Workflow
Rev 07-Nov-06
2
Analysis workflowAnalysis workflow
Three methods of analysis will be demonstrated
here:
line-fitting using the pressure derivative on the log-log plot
line-fitting to specialised diagnostic plots (Horner, square-
root, etc)
shape-matching using type-curves
All three approaches provide initial estimates of the
parameters
These are then refined using simulation
the theoretical response is matched to the measured data
by trial-and-error adjustment, or by auto-regression
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Example 3
3
File: example 3_1.pan
This is a shut-in test in an oil producer
Review well, layer and fluid data
Review pressure data and the rate history
Note that there
were several
flowing periods
and shut-ins
before this test,
but no pressure
data were
measured until
the final shut-in
Analysis workflowAnalysis workflow
4
Data qualityData qualityWell shut in
Check that the instant of shut-in (T0, P0) has
been correctly picked
Inspect the data for noise,
shifts, unusual behaviour
Something happened here!
This section of data can be
deleted.
Pressure shift and
change of slope
T0
P0
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Example 3
5
Analysis on the logAnalysis on the log--log plotlog plot
Enter Analysis, select the buildup test period in
the ruler bar, and go to the log-log plot
Adjust the derivative smoothing constant L
(under the T button)
PanSys plots P/ Q
on the y-axis, rather
than P, when there
is a multi-rate history
(‘rate normalised
pressure’)
The x-axis is the
Agarwal equivalent
drawdown time ( te), a
superposition function
The derivative is
computed as
P’ = P/ log( te)
6
Analysis on the logAnalysis on the log--log plotlog plot
Identify the probable flow regimes from the derivative
shape
Try PanWizard / Model
Selection
or the Derivative
Diagnostic Library
for guidance….
This looks like a Radial
homogeneous reservoir
with wellbore storage
The slight derivative upturn
at the end of the test suggests a possible remote heterogeneity….
Check Analysis / Model – the default models should be
appropriate
We will deal with the heterogeneity later….
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Example 3
7
Analysis on the logAnalysis on the log--log plotlog plot
The wellbore storage period looks fairly well-shaped
Select the unit-slope line and fit the line to the
storage-dominated data on the left
If no unit-slope trend on pressure and derivative at the beginning,
adjust T0 and/or P0
Do this using the T0 button in the menu bar, or return to the Data
Edit Plot in DataPrep and adjust (or re-pick) the shut-in event
Note Cs and Cd appear in the results box
Select the zero-slope line and fit to the zero-slope
portion of the derivative to obtain k from the radial flow
regime.
Fit the radial flow ‘FR’ markers to this portion of the data
to get an estimate of the mechanical skin factor S
8
Analysis on the logAnalysis on the log--log plotlog plot
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Example 3
9
Analysis on the logAnalysis on the log--log plotlog plot
Confirm results
Run Quick Match (under the
Simulate menu item)
The initial match should
be quite good, but can
be improved
Adjust Cs, k and S to
improve the match:
Cs shifts the unit-slope
portion of the derivative left
or right and affects the shape of the storage hump
k moves the radial flow portion of the derivative up or down
S moves the pressure up or down and affects the shape of
the storage hump
10
Analysis on the logAnalysis on the log--log plotlog plot
Delete the lines and flow regimes for a cleaner plot
Lines: right-click / {Del} key or
button
Regime: double-click in
coloured bar / Delete
Note how the computed
initial pressure Pi
changes as you adjust the
parameters
This is the theoretical
pressure at the start of the
rate history (first line of the
Rate Changes table)
For an infinite reservoir, this
is also the current reservoir pressure (no depletion)
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Example 3
11
Analysis on the logAnalysis on the log--log plotlog plot
An estimate of the distance to the suspected
heterogeneity can be obtained using the radius of
investigation calculation:
Position the mouse pointer where the
derivative starts to deviate from radial
flow
Check the Rinv read-out in the status
bar
Rinv
So there is “something” at about
500 ft (150 m) from the well…..
tC
tk03.0
12
Analysis using specialised plotsAnalysis using specialised plots
Clear Quick Match
Right-click on the trace, and tick ‘Hide match: all plots’
Fit the ‘FR’ markers for radial flow again
Go to the Radial Flow
Plot (‘semi-log’ plot)
This is the Horner super-
position plot
A line is fitted automatic-
ally to the radial flow data
k from slope, S from
intercept
P* (extrapolated to t = )
is equivalent to Pi from
Quick Match
Radial flow
Horner Plot
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Example 3
13
Analysis using specialised plotsAnalysis using specialised plots
Semilog Plot Results Box:
k: Effective permeability
kh: Permeability-thickness product
Rinv: Radius of investigation
FE: Flow Efficiency
dpS: Skin pressure drop/recovery
S: Skin factor (mechanical)
P*: Extrapolated pressure
14
Analysis using specialised plotsAnalysis using specialised plots
To refit a line:
Right-click on it and move/rotate it using the tabs that appear
Right-click on it, delete it with the button or the {Del} key and
then either:
Click in the flow regime band in the ruler bar and fit a line using
Define a range of data points by clicking once at each end, then fit a line
using
Click on the button and position the line using the tabs
Statistical details about a
selected line can be read
under the LR (Line Results)
button
Page 8
Edinburgh Petroleum Services PanSystem User Course
Example 3
15
Analysis using specialised plotsAnalysis using specialised plots
Since we have only radial flow, the Radial Flow Plot is the only
specialised plot that provides a
result from a line-fit in this example
Not strictly true! It is possible
to estimate the wellbore storage
coefficient Cs from the Cartesian
Plot (p vs t), since a unit slope
on the log-log plot derivative
implies that p t
A line through the first 3 or 4 data
points gives a value of Cs fairly
close to the one obtained from the
log-log plot
This line-fit is rarely used…..
16
Analysis using specialised plotsAnalysis using specialised plots
Having obtained results from the specialised plots, or from a
combination of log-log and specialised plots, the procedure would
now be to confirm the results and to refine the match using
Quick Match
This can be done on any plot: the log-log plot with derivative is
the most useful, but the radial flow plot gives better resolution for
the pressure match to get S
Page 9
Edinburgh Petroleum Services PanSystem User Course
Example 3
17
Analysis by typeAnalysis by type--curve matchingcurve matching
Clear Quick Match and go to the Type-Curve section
Click the button and
select the default Td/Cd
type-curves for Radial
homogeneous reservoir
with storage and skin
(Gringarten et al)
18
Analysis by typeAnalysis by type--curve matchingcurve matching
Match overall pressure and derivative shapes
Drag with the mouse, use the arrow keys for fine adjustment
Match vertically on the radial flow portion of the derivative k
Match laterally on the wellbore storage portion
CS
Click and accept (or change) the curve number S
Confirm results
Refine the match using Quick Match and review other plots
Page 10
Edinburgh Petroleum Services PanSystem User Course
Example 3
19
The button allows the pressure or derivative curve-
sets or labels to be hidden
Analysis by typeAnalysis by type--curve matchingcurve matching
20
The button lets you fix the vertical placement of the
type-curves according to a specified permeability
Analysis by typeAnalysis by type--curve matchingcurve matching
Page 11
Edinburgh Petroleum Services PanSystem User Course
Example 3
21
Match refinementMatch refinement
Return to the log-log plot and run Quick Match
We can tidy up the match to that derivative upturn at the end of the
test
There are a number of possible explanations. We will assume that
there is a fault there.
Analysis / Model – select single
fault as the boundary model
OK back to the plot
Now rerun Quick Match and
enter the distance estimated
from the radius of investigation
(500 ft / 150 m).
Adjust the distance to perfect the match
22
Match refinementMatch refinement
Final match to this dataset assuming a single fault
Note change in the model
has lead to a change in Pi
This new Pi can be
roughly reconciled
with P* from the
Horner Plot by fitting
a line to the very end
of the buildup
Radial Flow Plot
Page 12
Edinburgh Petroleum Services PanSystem User Course
Example 3
23
Still on the log-log plot, click the time function button
The default Use full history invokes
the superposition time function (based
on the time and rate data in the Rate
Changes table) for:
Derivative computation
X-axis of most plots
It is theoretically rigorous and valid for most situations
Superposition theory is used so that tests which are not constant
rate drawdowns can be plotted in such a way that they look like
constant rate drawdowns. In this way, we can apply the same
line-fitting, derivative shape recognition, etc rules to all tests.
The derivative P’ = P/ log( te) where te is the Agarwal
equivalent time, a form of superposition function
Time function button Time function button TfTf
24
Use constant rate history simplifies
a multi-rate history to a single rate
using the last flowrate and an
effective producing time Tpeff
Tpeff = Total volume produced / last rate before shut-in
This equivalence was useful in the days before computers….
No history ignores the rate history: no superposition is used for
the derivative computation or plots
In all but a few situations, this is not recommended
Use Horner has no effect on the log-log plot
Time function button Time function button TfTf
Page 13
Edinburgh Petroleum Services PanSystem User Course
Example 3
25
Time function button Time function button TfTf
No history – log-log plot without superposition
Derivative has different shape (compare previous log-log plot)
Model recognition using drawdown rules
is no longer so easy
But, since we have
already done an
analysis, note how the
simulated trace still
matches the data
If the model is correct, the two will always match, no matter how they are plotted…
180 md
26
Alternative Radial Flow Plot presentation – Agarwal Plot
This presentation
uses full history,
but ‘Horner’ is
switched off
The x-axis is ‘Equivalent time’ (Agarwal equivalent drawdown time),
an alternative form of superposition function
Pcalc is equivalent to Pi from the Horner plot
For a buildup, the Horner Plot is more commonly used
Time function button Time function button TfTf
Radial flow
Page 14
Edinburgh Petroleum Services PanSystem User Course
Example 3
27
Another Radial Flow Plot presentation – the MDH Plot
This presentation
uses no history,
and ‘Horner’ is
switched off
The x-axis is ‘Elapsed time’, no superposition is used
Note slight downturn from the straight line trend at the end
This is because superposition is not being used
Compare with log-log plot using No history
Time function button Time function button TfTf
Radial flow
28
Tiled plotsTiled plots
Page 15
Edinburgh Petroleum Services PanSystem User Course
Example 3
29
Derivative Diagnostic LibraryDerivative Diagnostic Library
Page 1
Edinburgh Petroleum Services PanSystem User Course
Example 3
Example 3Example 3
Analysis Workflow
Rev 07-Nov-06
2
Analysis workflowAnalysis workflow
Three methods of analysis will be demonstrated
here:
line-fitting using the pressure derivative on the log-log plot
line-fitting to specialised diagnostic plots (Horner, square-
root, etc)
shape-matching using type-curves
All three approaches provide initial estimates of the
parameters
These are then refined using simulation
the theoretical response is matched to the measured data
by trial-and-error adjustment, or by auto-regression
Page 2
Edinburgh Petroleum Services PanSystem User Course
Example 3
3
File: example 3_1.pan
This is a shut-in test in an oil producer
Review well, layer and fluid data
Review pressure data and the rate history
Note that there
were several
flowing periods
and shut-ins
before this test,
but no pressure
data were
measured until
the final shut-in
Analysis workflowAnalysis workflow
4
Data qualityData qualityWell shut in
Check that the instant of shut-in (T0, P0) has
been correctly picked
Inspect the data for noise,
shifts, unusual behaviour
Something happened here!
This section of data can be
deleted.
Pressure shift and
change of slope
T0
P0
Page 3
Edinburgh Petroleum Services PanSystem User Course
Example 3
5
Analysis on the logAnalysis on the log--log plotlog plot
Enter Analysis, select the buildup test period in
the ruler bar, and go to the log-log plot
Adjust the derivative smoothing constant L
(under the T button)
PanSys plots P/ Q
on the y-axis, rather
than P, when there
is a multi-rate history
(‘rate normalised
pressure’)
The x-axis is the
Agarwal equivalent
drawdown time ( te), a
superposition function
The derivative is
computed as
P’ = P/ log( te)
6
Analysis on the logAnalysis on the log--log plotlog plot
Identify the probable flow regimes from the derivative
shape
Try PanWizard / Model
Selection
or the Derivative
Diagnostic Library
for guidance….
This looks like a Radial
homogeneous reservoir
with wellbore storage
The slight derivative upturn
at the end of the test suggests a possible remote heterogeneity….
Check Analysis / Model – the default models should be
appropriate
We will deal with the heterogeneity later….
Page 4
Edinburgh Petroleum Services PanSystem User Course
Example 3
7
Analysis on the logAnalysis on the log--log plotlog plot
The wellbore storage period looks fairly well-shaped
Select the unit-slope line and fit the line to the
storage-dominated data on the left
If no unit-slope trend on pressure and derivative at the beginning,
adjust T0 and/or P0
Do this using the T0 button in the menu bar, or return to the Data
Edit Plot in DataPrep and adjust (or re-pick) the shut-in event
Note Cs and Cd appear in the results box
Select the zero-slope line and fit to the zero-slope
portion of the derivative to obtain k from the radial flow
regime.
Fit the radial flow ‘FR’ markers to this portion of the data
to get an estimate of the mechanical skin factor S
8
Analysis on the logAnalysis on the log--log plotlog plot
Page 5
Edinburgh Petroleum Services PanSystem User Course
Example 3
9
Analysis on the logAnalysis on the log--log plotlog plot
Confirm results
Run Quick Match (under the
Simulate menu item)
The initial match should
be quite good, but can
be improved
Adjust Cs, k and S to
improve the match:
Cs shifts the unit-slope
portion of the derivative left
or right and affects the shape of the storage hump
k moves the radial flow portion of the derivative up or down
S moves the pressure up or down and affects the shape of
the storage hump
10
Analysis on the logAnalysis on the log--log plotlog plot
Delete the lines and flow regimes for a cleaner plot
Lines: right-click / {Del} key or
button
Regime: double-click in
coloured bar / Delete
Note how the computed
initial pressure Pi
changes as you adjust the
parameters
This is the theoretical
pressure at the start of the
rate history (first line of the
Rate Changes table)
For an infinite reservoir, this
is also the current reservoir pressure (no depletion)
Page 6
Edinburgh Petroleum Services PanSystem User Course
Example 3
11
Analysis on the logAnalysis on the log--log plotlog plot
An estimate of the distance to the suspected
heterogeneity can be obtained using the radius of
investigation calculation:
Position the mouse pointer where the
derivative starts to deviate from radial
flow
Check the Rinv read-out in the status
bar
Rinv
So there is “something” at about
500 ft (150 m) from the well…..
tC
tk03.0
12
Analysis using specialised plotsAnalysis using specialised plots
Clear Quick Match
Right-click on the trace, and tick ‘Hide match: all plots’
Fit the ‘FR’ markers for radial flow again
Go to the Radial Flow
Plot (‘semi-log’ plot)
This is the Horner super-
position plot
A line is fitted automatic-
ally to the radial flow data
k from slope, S from
intercept
P* (extrapolated to t = )
is equivalent to Pi from
Quick Match
Radial flow
Horner Plot
Page 7
Edinburgh Petroleum Services PanSystem User Course
Example 3
13
Analysis using specialised plotsAnalysis using specialised plots
Semilog Plot Results Box:
k: Effective permeability
kh: Permeability-thickness product
Rinv: Radius of investigation
FE: Flow Efficiency
dpS: Skin pressure drop/recovery
S: Skin factor (mechanical)
P*: Extrapolated pressure
14
Analysis using specialised plotsAnalysis using specialised plots
To refit a line:
Right-click on it and move/rotate it using the tabs that appear
Right-click on it, delete it with the button or the {Del} key and
then either:
Click in the flow regime band in the ruler bar and fit a line using
Define a range of data points by clicking once at each end, then fit a line
using
Click on the button and position the line using the tabs
Statistical details about a
selected line can be read
under the LR (Line Results)
button
Page 8
Edinburgh Petroleum Services PanSystem User Course
Example 3
15
Analysis using specialised plotsAnalysis using specialised plots
Since we have only radial flow, the Radial Flow Plot is the only
specialised plot that provides a
result from a line-fit in this example
Not strictly true! It is possible
to estimate the wellbore storage
coefficient Cs from the Cartesian
Plot (p vs t), since a unit slope
on the log-log plot derivative
implies that p t
A line through the first 3 or 4 data
points gives a value of Cs fairly
close to the one obtained from the
log-log plot
This line-fit is rarely used…..
16
Analysis using specialised plotsAnalysis using specialised plots
Having obtained results from the specialised plots, or from a
combination of log-log and specialised plots, the procedure would
now be to confirm the results and to refine the match using
Quick Match
This can be done on any plot: the log-log plot with derivative is
the most useful, but the radial flow plot gives better resolution for
the pressure match to get S
Page 9
Edinburgh Petroleum Services PanSystem User Course
Example 3
17
Analysis by typeAnalysis by type--curve matchingcurve matching
Clear Quick Match and go to the Type-Curve section
Click the button and
select the default Td/Cd
type-curves for Radial
homogeneous reservoir
with storage and skin
(Gringarten et al)
18
Analysis by typeAnalysis by type--curve matchingcurve matching
Match overall pressure and derivative shapes
Drag with the mouse, use the arrow keys for fine adjustment
Match vertically on the radial flow portion of the derivative k
Match laterally on the wellbore storage portion
CS
Click and accept (or change) the curve number S
Confirm results
Refine the match using Quick Match and review other plots
Page 10
Edinburgh Petroleum Services PanSystem User Course
Example 3
19
The button allows the pressure or derivative curve-
sets or labels to be hidden
Analysis by typeAnalysis by type--curve matchingcurve matching
20
The button lets you fix the vertical placement of the
type-curves according to a specified permeability
Analysis by typeAnalysis by type--curve matchingcurve matching
Page 11
Edinburgh Petroleum Services PanSystem User Course
Example 3
21
Match refinementMatch refinement
Return to the log-log plot and run Quick Match
We can tidy up the match to that derivative upturn at the end of the
test
There are a number of possible explanations. We will assume that
there is a fault there.
Analysis / Model – select single
fault as the boundary model
OK back to the plot
Now rerun Quick Match and
enter the distance estimated
from the radius of investigation
(500 ft / 150 m).
Adjust the distance to perfect the match
22
Match refinementMatch refinement
Final match to this dataset assuming a single fault
Note change in the model
has lead to a change in Pi
This new Pi can be
roughly reconciled
with P* from the
Horner Plot by fitting
a line to the very end
of the buildup
Radial Flow Plot
Page 12
Edinburgh Petroleum Services PanSystem User Course
Example 3
23
Still on the log-log plot, click the time function button
The default Use full history invokes
the superposition time function (based
on the time and rate data in the Rate
Changes table) for:
Derivative computation
X-axis of most plots
It is theoretically rigorous and valid for most situations
Superposition theory is used so that tests which are not constant
rate drawdowns can be plotted in such a way that they look like
constant rate drawdowns. In this way, we can apply the same
line-fitting, derivative shape recognition, etc rules to all tests.
The derivative P’ = P/ log( te) where te is the Agarwal
equivalent time, a form of superposition function
Time function button Time function button TfTf
24
Use constant rate history simplifies
a multi-rate history to a single rate
using the last flowrate and an
effective producing time Tpeff
Tpeff = Total volume produced / last rate before shut-in
This equivalence was useful in the days before computers….
No history ignores the rate history: no superposition is used for
the derivative computation or plots
In all but a few situations, this is not recommended
Use Horner has no effect on the log-log plot
Time function button Time function button TfTf
Page 13
Edinburgh Petroleum Services PanSystem User Course
Example 3
25
Time function button Time function button TfTf
No history – log-log plot without superposition
Derivative has different shape (compare previous log-log plot)
Model recognition using drawdown rules
is no longer so easy
But, since we have
already done an
analysis, note how the
simulated trace still
matches the data
If the model is correct, the two will always match, no matter how they are plotted…
180 md
26
Alternative Radial Flow Plot presentation – Agarwal Plot
This presentation
uses full history,
but ‘Horner’ is
switched off
The x-axis is ‘Equivalent time’ (Agarwal equivalent drawdown time),
an alternative form of superposition function
Pcalc is equivalent to Pi from the Horner plot
For a buildup, the Horner Plot is more commonly used
Time function button Time function button TfTf
Radial flow
Page 14
Edinburgh Petroleum Services PanSystem User Course
Example 3
27
Another Radial Flow Plot presentation – the MDH Plot
This presentation
uses no history,
and ‘Horner’ is
switched off
The x-axis is ‘Elapsed time’, no superposition is used
Note slight downturn from the straight line trend at the end
This is because superposition is not being used
Compare with log-log plot using No history
Time function button Time function button TfTf
Radial flow
28
Tiled plotsTiled plots
Page 15
Edinburgh Petroleum Services PanSystem User Course
Example 3
29
Derivative Diagnostic LibraryDerivative Diagnostic Library
Example 4
Page 1
Edinburgh Petroleum Services PanSystem User Course
Example 4Example 4
Faults and Boundaries
Rev 07-Nov-06
2
Single noSingle no--flow boundaryflow boundary
A producing well at a distance L from a sealing fault (‘no-flow
boundary’):
The response is the same as if there were an identical producer a distance 2L away in an infinite reservoir
The mathematics is now straightforward – add the interference from the ‘image well’ (Ei-function) onto the response of the test well (semi-log function)
This results in an eventual doubling of the semi-log slope after the interference signal arrives, as the Ei-function becomes semi-logarithmic when Td/4Ld
2 > 25:2 wells pwf 2 log t
This is still a form of radial flow (“hemi-radial”)
q L
Test well
q qL L
Image wellTest well
Real no-flow boundary Virtual no-flow boundary
Example 4
Page 2
Edinburgh Petroleum Services PanSystem User Course
3
Intersecting noIntersecting no--flow boundariesflow boundaries
For 90° intersecting faults we need 3 image wells:
This will produce a quadrupling of slope when the 3 interferencesignals are superposed on the test well response
4 wells pwf 4 log t . This is still radial flow (“hemi-demi-radial”).
The general rule is that n = 360 °
The method of images can be used for some, but not all, integer values of n
Other methods can be used for other angles
L2
Test well
q
L1
q
L1
L2L2
L1
q
4
For parallel faults we need image wells:
Each image has its own image in the other boundary ….ad infinitum
When these image interference signals are superposed on the test well response, the result is….. pwf t
This is linear flow - the derivative has a half-slope
For a closed channel (U-shaped), each of these images will have its own image in the end boundary
This is hemi-linear flow - the derivative still has a half-slope but is displaced upwards
Parallel noParallel no--flow boundariesflow boundaries
q
Test well
L1
L3
q
q
q
q
q
q
q
Example 4
Page 3
Edinburgh Petroleum Services PanSystem User Course
5
Dp
2/ DD Lt
.
.
.
.
4x (hemi-demi-radial)
0.1 1 10 100 1000
0.1
0.5
1
10
100
Elementary derivative responsesElementary derivative responses
2x (hemi-radial)
Half-slope (linear)Half-slope (hemi-linear)
Radial
These shapes are for boundaries which are equidistant from the well
For non-equidistant boundaries, the response will develop
one boundary at a time
6
ObjectivesObjectives
Identify model
Reservoir permeability k
True (mechanical) skin factor S
Boundaries present?
Boundary geometry
Boundary distances
Boundary types
Example 4
Page 4
Edinburgh Petroleum Services PanSystem User Course
7
Faults and boundariesFaults and boundaries
File: example 4_1.pan
This is a flowing test in an oil producer
Review well, layer and fluid data
Review pressure data and rate history
Note that this pressure buildup is due to a
reduction in production rate, not a shut-in
8
Analysis on the logAnalysis on the log--log plotlog plot
Identify the probable flow regimes from the
derivative by trying different line slopes
This looks like a Radial homogeneous reservoir
with a boundary or other remote heterogeneity
Wellbore storage looks non-ideal
Check the T0, P0 pick on the Data Edit plot
Obtain k from the late radial flow regime. Confirm .
Fit the radial ‘FR’ markers to get an estimate of the
mechanical skin factor S
Example 4
Page 5
Edinburgh Petroleum Services PanSystem User Course
9
Analysis on the logAnalysis on the log--log plotlog plot
What might be causing the upturn in the
derivative?
10
Analysis on the logAnalysis on the log--log plotlog plot
The distance to the
heterogeneity can be
estimated using the radius
of investigation read-out in
the status bar beneath the
plot
Position the mouse pointer
where the derivative starts to
rise from the zero-slope line
This will be refined later by simulation
Select the single fault boundary model in
Analysis / ModelStart with the simplest model….
Example 4
Page 6
Edinburgh Petroleum Services PanSystem User Course
11
Analysis on the logAnalysis on the log--log plotlog plot
Run Quick match and
adjust the distance L1
Adjust Cs to match the
latter part of the wbs
Check the final match
on all plots
12
Analysis using specialised plotsAnalysis using specialised plots
Log-log plot - clear Quick Match. Fit the ‘FR’ markers for
radial flow and single fault (hemi-)radial flow
Go to the Radial Flow Plot
to obtain k, S, PCalc and L1
L1 is computed fromthe time of intersection (Tx) of the two lines
It will not be very goodbecause the second radial flow regime didnot develop fully
PCalc is equivalent to P* on a Horner Plot
Confirm results , refine
match using Quick Match
Check the final match on all plots
Single fault
radial flow
(almost!)
Radial flow
Tx
Example 4
Page 7
Edinburgh Petroleum Services PanSystem User Course
13
Analysis by typeAnalysis by type--curve matchingcurve matching
Clear Quick Match and go to the Type-Curve
section
Select the default Td/Cd (Gringarten et al) type-curves
Match the pressure
and derivative
Use the arrow
keys for fine
adjustment
Matching in the x-
direction is difficult
owing to the shape
of the wbs period…
Click and
Confirm results
14
Analysis by typeAnalysis by type--curve matchingcurve matching
Click the right arrow button to move to the next
matching stage (a subset of boundaries)
Move the curves sideways – the vertical position is locked to
respect the permeability
X-axis of these curves
is Td/Ld2
Ld = L/rw
So sideways match gives L
Confirm results
Refine the match using
Quick Match
Example 4
Page 8
Edinburgh Petroleum Services PanSystem User Course
15
Faults and boundariesFaults and boundaries
File: example 4_2.pan
This is a long shut-in test in an oil producer
Review well, layer and fluid data
Review pressure data and rate history
16
Analysis on the logAnalysis on the log--log plotlog plot
Identify the possible flow regimes from the derivative
Possible radial flow immediately after wellbore storage?
…and possibly not…..
Two other radial flow portions (CHECK NEXT SLIDE…)
Derivative approximately doubles from one regime to the next
Possibly a Radial homogeneous reservoir
with perpendicular boundaries, one closer than the other?
select this model in Analysis / Model
Wellbore storage looks fairly ideal
Storage could be partially masking the initial radial flow regime
If we fit a zero-slope line at the bottom of the derivative trough, we will get a lower limit to k
Fit the radial ‘FR’ marker to get an estimate of the mechanical skin
factor S
Confirm results
Example 4
Page 9
Edinburgh Petroleum Services PanSystem User Course
17
Analysis on the logAnalysis on the log--log plotlog plot
If you are plotting Equivalent time on the x-axis, you will
not see a radial flow regime at the end…..
It looks more like
linear flow
This is an artefact
of the compression
that occurs with
Equivalent time
when shut-in time
>> Tp
Try the ‘Plot against
elapsed time’ option
(under the T button)
to remove this
compression
18
Radial flow (second fault)
Radial flow (first fault)
Radial flow
(partially obscured)
Wellbore storage
Analysis on the logAnalysis on the log--log plotlog plot
If we assume initially that radial flow is at the derivative minimum,
then k 42 md
There are two other well-developed zero-slope regimes (radial flow)
with approx doubling of values
So we may have:
Radial flow (partiallyobscured by storage)
‘Hemi-radial’ flow from first fault
‘Hemi-demi’-radialflow from second(perpendicular)fault
89
176
57
Example 4
Page 10
Edinburgh Petroleum Services PanSystem User Course
19
Analysis on the logAnalysis on the log--log plotlog plot
We can be smarter here:
if the second radial flow is caused by a fault, then the first radial flow
line should be at 89 2 = 44.5
Reposition this line and get
k 52 md
Confirm results
The approximate distance
to each boundary can be
got from the radius of investigation:
Place the mouse pointer where the derivative starts to rise from the radial
flow line….
…approx 55 ft (17 m) and 470 ft (143 m)
89
176
44.5
20
Analysis on the logAnalysis on the log--log plotlog plot
Run Quick Match (select ‘Variable well position’)
Enter the boundary distances
The initial match should be quite close
Adjust the parameters
to perfect the match
This is a good case for
Auto Match…
Example 4
Page 11
Edinburgh Petroleum Services PanSystem User Course
21
Analysis on the logAnalysis on the log--log plotlog plot
Set Cs=0 to appreciate how the initial radial flow regime has been
obscured:
For radial flow to develop clearly, the first boundarywould have to be more than about 50 ft (50 m) away
Downhole shut-ins reduceCs to a minimum and maximise the chances ofseeing the radial flowregime. But if the fault is still too close…..
Set Cs=0.023 bbls/psi (10 times as big) to see the effect
of a surface shut-in…..
22
Analysis using specialised plotsAnalysis using specialised plots
Log-log plot - clear Quick Match. Fit the ‘FR’ markers for Radial
flow and Intersecting fault radial flow
Go to the Radial Flow (Horner) plot
First radial flow line gives k and S
Second radial flow line gives distance L to the two faults, assuming them to be equidistant (not very useful!)
There is no estimate of distance to the first fault
P* is good (well-developedradial flow regime)
Refine the match with Quick Match or Auto Match
Radial flow
Intersecting fault
radial flow
Example 4
Page 12
Edinburgh Petroleum Services PanSystem User Course
23
Analysis by typeAnalysis by type--curve matchingcurve matching
Clear Quick Match and go to the Type-Curve section
Select the default Td/Cd (Gringarten et al) type-curves
Match the pressure
and derivative
Use the arrow keys for fine
adjustment
Curve 5 is a good match to
the wbs-dominated data, if
we assume radial flow
at the bottom of the
derivative trough
Click the M button again
Confirm results
24
Analysis by typeAnalysis by type--curve matchingcurve matching
Click the right-arrow button to move to the next
matching stage (a subset of boundary type-curves)
Move the curves sideways – the vertical position is locked to
respect the permeability
X-axis of these curves
is Td/Ld2
Ld = L/rw
So sideways match gives L
Match to the first fault
Radial flow portion of type-
curve lies above the data
Wrong k !
Click to close the
match
Example 4
Page 13
Edinburgh Petroleum Services PanSystem User Course
25
Analysis by typeAnalysis by type--curve matchingcurve matching
Click the left-arrow button twice to return to the start,
click and select the Td/Cd type-curves again
Rematch the pressure
and derivative
Curve # 6 is a good
match if we do not
assume radial flow
at the bottom of the
trough
Click and confirm
results
26
Analysis by typeAnalysis by type--curve matchingcurve matching
Click the right arrow button to move to the boundary
matching stage:
Move the curves sideways
Match to the first fault
Hemi-radial flow portion
of the type-curve now fits
the data more closely
L 42 ft (13 m)
Example 4
Page 14
Edinburgh Petroleum Services PanSystem User Course
27
Analysis by typeAnalysis by type--curve matchingcurve matching
Move the curves sideways
and match to the second
fault
Click the button again
L 395 ft (120 m)
Run Quick Match and
input the values for L1
and L2
Refine the match manually
or using Auto Match
28
Fang
Wang
(fraction
of Fang)
Lint
IBDY2=1 (no-flow)
IBDY1=1 (no-flow)
Alternative Alternative ‘‘General intersecting faultsGeneral intersecting faults’’
modelmodel
Enter Analysis / Model and open a new interpretation
Select the General intersecting fault flow model
Set the Boundary model to Infinite acting
Run Quick Match, and adjust the parameters
to obtain a match
Example 4
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Edinburgh Petroleum Services PanSystem User Course
29
Faults and boundariesFaults and boundaries
File: example 4_3.pan
This is a shut-in test in an oil producer
Review well, layer and fluid data
Review pressure data and rate history
30
Analysis on the logAnalysis on the log--log plotlog plot
Identify the probable flow regimes from the derivative
Note well-developed half-slope linear flow?
Possibly a Radial homogeneous reservoir
with parallel boundaries? select this model in Analysis /
Model
Wellbore storage looks non-ideal
Check the T0, P0 pick on the Data Edit plot…
If we fit a zero-slope line at the bottom of the derivative trough, we
will get a lower limit to k
Fit the radial ‘FR’ marker to get an estimate of the mechanical skin
factor S
Fit a half-slope line to get the channel width W
Confirm results
Example 4
Page 16
Edinburgh Petroleum Services PanSystem User Course
31
Analysis on the logAnalysis on the log--log plotlog plot
Assume radial flow is at the derivative minimum
There is a well-developed half-slope linear flow
32
Analysis on the logAnalysis on the log--log plotlog plot
Run Quick Match, select ‘Central well position’
and adjust the distance L
Reduce Cs to keep it out of the way for the time-
being
Even with L1 L3,
the match to the
linear flow portion
is not quite right
Select the ‘U-shaped’
boundary model and
try again…..
Example 4
Page 17
Edinburgh Petroleum Services PanSystem User Course
33
Analysis on the logAnalysis on the log--log plotlog plot
Adjust the distances L1, L2 and L3 to obtain a
match
Adjust by trial and error
Try Auto Match
Fix k
Fix Cs=0 and do not include anywellbore storagepoints
This model does
a slightly better
job…
34
Analysis on the logAnalysis on the log--log plotlog plot
For the wellbore storage either:
Leave Cs = 0
Bring in a small Cs to match just the end of the wbs-dominated
derivative
Select the a Varying
wellbore storage
model and attempt
a match
This match was obtained with the Hegeman model
Example 4
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Edinburgh Petroleum Services PanSystem User Course
35
Check the match on
other plots….
Approx radial flow
Linear flow
Linear flow plot
Radial flow plot
36
Analysis using specialised plotsAnalysis using specialised plots
Log-log plot - clear Quick Match. Fit the ‘FR’ markers
for radial and hemi-linear flow
Go to the Radial
Flow Plot to obtain k
and S
Note P* is much too low
This is because the last
observed flow regime was
linear, not radial, so the
semi-log plot is the wrong
one to use for P*
Confirm resultsRadial flow plot
Example 4
Page 19
Edinburgh Petroleum Services PanSystem User Course
37
Analysis using specialised plotsAnalysis using specialised plots
Go to the Radial Flow Plot to obtain channel width W
from the slope of the line
Note P* is close to Pi
from Quick Match
The last observed flow
regime was linear,
so the square-root plot
is the one to use for P*
For the ‘parallel fault’
model, this line-fit also
gives the convergence
skin Sconv
Confirm results
Run Quick Match to
refine the results manually, or use Auto Match
Linear flow plot
38
Two special casesTwo special cases
Non-sealing faultFault of finite extent
Example 4
Page 20
Edinburgh Petroleum Services PanSystem User Course
39
Non-sealing fault‘Partially sealing fault’ model
Fault of finite extentNumerical modelling
SealingInfinite length
Finite length
Highly conductive
Conductive
See file Example 4_Odd faults.pan
Two special casesTwo special cases
40
Partially sealing fault modelPartially sealing fault model
h2: The layer thickness on the far side of the fault
The layer thickness (h) specified in the Layer Parameters dialog is on the well side of the fault.
L1: The distance from the well to the fault.
Fc: The conductivity of the partially sealing fault:
Fc = Permeability of fault zone ÷ width of fault zone.
Plan viewh2
h
Side view
L1
Example 4
Page 21
Edinburgh Petroleum Services PanSystem User Course
41
Fault of finite lengthFault of finite length
Advance of pressure disturbance around the fault – numerical
modelling with PanMesh
42
Derivative Diagnostic LibraryDerivative Diagnostic Library
Example 4
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Edinburgh Petroleum Services PanSystem User Course
43
Derivative Diagnostic LibraryDerivative Diagnostic Library
44
Derivative Diagnostic LibraryDerivative Diagnostic Library
Example 4
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Edinburgh Petroleum Services PanSystem User Course
45
Derivative Diagnostic LibraryDerivative Diagnostic Library
Page 1
Edinburgh Petroleum Services PanSystem User Course
Example 5
EX 5.1Example 5Example 5
Dual Porosity Reservoir
EX 5.2DATAPREPDATAPREP
• Load file Example05.PAN
• This is a Pre-prepared pan file
• Before going on to Analysis
• Review Dataprep sections
– Make sure all the required information (Well, Layer
and Fluid parameters) has been defined properly.
Page 2
Edinburgh Petroleum Services PanSystem User Course
Example 5
EX 5.3DATAPREPDATAPREPThis is an actual constant rate drawdown (CRD) test
for a vertical oil well.
EX 5.4ANALYSISANALYSISANALYSIS-PLOT
– Select the drawdown test period and go to Log-Log plot:
• Do you recognise the character of the Log-Log
derivative diagnostic plot ?
• Note: only allowed deltaT (elapsed time) as time
function on the x-axis
• Select the appropriate analysis model (Dual-Porosity
(Pseudo Steady State))
• Define the following flow regimes:
– Wellbore storage
– Transition to system radial flow
– System radial flow
• Confirm results
Page 3
Edinburgh Petroleum Services PanSystem User Course
Example 5
EX 5.5ANALYSISANALYSIS
Dual Porosity Behaviour
(Transition to system radial flow)
Total System
Radial Flow
Wellbore Storage effect
EX 5.6Semi-Log Plot:
• Does it look just what you expect from having seen on the
Log-Log derivative ?
• If there is any fracture radial flow, the trend should be
parallel to system radial flow so use parallel line button and
add a parallel line.
• A value for should be calculated as is a function of the
vertical distance between these two parallel lines.
• Select the “Transition to system radial flow” flow regime
and add the best fit line.
• A value for should be calculated as it is a function of the
trend of the transition zone.
• Confirm Results
ANALYSISANALYSIS
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Edinburgh Petroleum Services PanSystem User Course
Example 5
EX 5.7ANALYSISANALYSIS
EX 5.8ANALYSISANALYSISDual Porosity Parameters:
: Fracture Storativity, it represents the fracture
volume compared with total volume. Smaller
means smaller fracture volume or more matrix
volume so deeper V shape behaviour on the log-
log plot.
: Interporosity flow coefficient, it represents the
flow between the matrix and fracture. Higher
means sooner and better matrix support
therefore on the log-log plot it does move the V
shape to the left hand side.
Page 5
Edinburgh Petroleum Services PanSystem User Course
Example 5
EX 5.9ANALYSISANALYSISOnce you have got all parameters…
• Select Log-Log plot
• SIMULATE-QUICK MATCH
• Fine tune the analysis parameters to get the final match
• Check Semi-log, Cartesian, and test overview match
• We are getting the fracture’s permeability-thickness product not the fracture permeability as it is not relevant.
• The skin factor represents the intersection of the fracture network and the wellbore.
EX 5.10ANALYSISANALYSISFinal results and match:
Page 6
Edinburgh Petroleum Services PanSystem User Course
Example 5
EX 5.11TYPE CURVESTYPE CURVES• Use TC button to start type curve analysis
• Use Type curve match button
• 1st Stage
– Chose Derivative Match/Dual Porosity (PSS flow)
– Get k, ,
EX 5.12TYPE CURVESTYPE CURVES
Red parameters
are not calculated
by TC matching.
Page 7
Edinburgh Petroleum Services PanSystem User Course
Example 5
EX 5.13
2nd Stage :
Use Next stage of type curve matching button to
calculate Cs and S
• Confirm results
• SIMULATE-QUICK MATCH to combine the type curves and
fine tune the parameters
TYPE CURVESTYPE CURVES
EX 5.14Example 5Example 5
END OF EXAMPLE 5
Example 6
Page 1
Edinburgh Petroleum Services PanSystem User Course
EX 6.1Example 6Example 6
Closed Reservoirs
EX 6.2
• Load file Example06.PAN
• This is a Pre-prepared pan file
• Before going on to Analysis
• Review Dataprep sections
– Make sure all the required information (Well, Layer
and Fluid parameters) has been defined properly.
DATAPREPDATAPREP
Example 6
Page 2
Edinburgh Petroleum Services PanSystem User Course
EX 6.3DATAPREPDATAPREP• This is an actual Extended (Reservoir Limit) test for
a vertical oil well.
• The main objective of an extended test is to get the
distances to all boundaries and calculate the amount
of hydrocarbon connected to a particular well.
• The main criteria of this type of tests is to reach
Semi-Steady-State behaviour during which the
flowing pressure is a linear function of time.
EX 6.4AnalysisAnalysis
Semi-Steady-State behaviour
Example 6
Page 3
Edinburgh Petroleum Services PanSystem User Course
EX 6.5AnalysisAnalysis
• On the log-log diagnostic plot, the late time
characteristics of SSS is Unit Slope trend on the
derivative.
• Set the model to Closed System
• Analysis Model Boundary Model
• Define all appropriate flow regimes
• Wellbore storage (not enough points)
• Radial Flow
• Closed System PSS flow
• Confirm results
EX 6.6AnalysisAnalysis
Radial Flow
(Middle Time Region)
PSS Unit Slope Trend
(Late Time Region)
Example 6
Page 4
Edinburgh Petroleum Services PanSystem User Course
EX 6.7AnalysisAnalysis
• As usual go to Semi-log plot and confirm the
results (K, S, etc...)
• On the Cartesian plot, the best fit line through
the late time region will provide the Area,
Volume, and Dietz shape factor.
• The area/volume is a function of the line slope
and Dietz shape factor is a function of area and
the line’s intercept.
• Confirm results
EX 6.8AnalysisAnalysis
Best fit line through
PSS flow regime
Example 6
Page 5
Edinburgh Petroleum Services PanSystem User Course
EX 6.9Closed ReservoirClosed Reservoir
• Use SIMULATE-QUICK MATCH to fine tune
the analysis parameters.
– Wellbore Storage, Cs = 0.009 bbl/psi
– Permeability, k = 7.6 mD
– Skin, S = 6.25
– Distance to Boundary, L = 1300 ft
– Initial Pressure, Pi = 4412 psia
– Dietz shape factor, Ca = 31.6
– Drainage area = 153 acres
• Save the file
EX 6.10Example 6Example 6
END OF EXAMPLE 6
Example 7
Page 1
Edinburgh Petroleum Services PanSystem User Course
EX 7.1
Parallel Faults
and
Phase Redistribution Effect
Example 7
EX 7.2DataprepDataprep
• Load file Example07.pan
• Review Well, Layer, and Fluid
parameters
• Review the gauge data in Dataprep
• Check the Rate changes table
• This is a constant rate PBU test for a
vertical oil well.
Example 7
Page 2
Edinburgh Petroleum Services PanSystem User Course
EX 7.3AnalysisAnalysis• Select the BU test period and start with the
log-log plot.
• Examine the shape of the derivative
• Select T’ button
– plot linear derivative with smoothing factor of 0.2(smoothing factor determines the window in which the data points will be used for derivative calculation.)
• Note late time linear flow:
–Radial derivative is following half slope trend
–Linear derivative is following zero slope line trend
• Remove Linear derivative
EX 7.4AnalysisAnalysis
Half slope trend on radial
derivative, an indication of
parallel faults or channel
Zero slope trend on linear
derivative, confirming linear
flow in a channel
Example 7
Page 3
Edinburgh Petroleum Services PanSystem User Course
EX 7.5
There are three possible reservoir / boundary models
to analyse this test:
• Variable wellbore storage effect (phase redistribution),
radial homogeneous with parallel faults equidistant
• Dual porosity with parallel faults equidistant, follow the
same procedure as in Example05.
• A no-flow boundary very close to the wellbore followed by
single fault radial flow and finally another no-flow
boundary parallel to the first one, follow the same
procedure as in Example04.
AnalysisAnalysis
EX 7.6AnalysisAnalysis
• Select Analysis / Model
– Select Fair wellbore storage
– Change the reservoir model to Radial
homogeneous
– Change the boundary model to Parallel faults
• Select FR on the toolbar and mark the different
flow regimes
• Wellbore storage is not clearly seen on this test, so
the first point will give the maximum Cs value.
Example 7
Page 4
Edinburgh Petroleum Services PanSystem User Course
EX 7.7LogLog--Log PlotLog Plot
Variable wellbore
storage effcet
Middle time region,
infinite acting
radial flow
Late time region,
linear flow in a
channel
EX 7.8• Select Semi-log plot, confirm the permeability, skin
factor, etc...
• Make note of the extrapolated pressure value
• Select the Linear flow plot (square root of time)
• Confirm all results on this analysis plot
• Make note of the extrapolated pressure
– How do you compare this pressure value with the one
from semi-log plot ?
– Which one is more reliable ? Why ?
• Confirm Results
AnalysisAnalysis
Example 7
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Edinburgh Petroleum Services PanSystem User Course
EX 7.9Linear Flow PlotLinear Flow Plot
EX 7.10Linear Flow PlotLinear Flow PlotLinear Flow Plot Results:
W: Channel width, ft
L1: Distance to the first no-flow boundary, ft
Sconv: Convergence skin
P*: Extrap. Press. from linear flow plot, psia
A
B
C
In order to produce oil particles A and C compared with oil particle B more
pressure drop is required. This extra pressure drop is called convergence skin.
Example 7
Page 6
Edinburgh Petroleum Services PanSystem User Course
EX 7.11Variable WBSVariable WBSThe variable wellbore storage parameters are as follows:
• Wellbore Storage coefficient (Cs) is the final value when phase redistribution effects
have dissipated.
• Storage Amplitude (Cphi) is the maximum phase redistribution pressure change. It
can be positive (= increasing wellbore storage - e.g. "humping" caused by rising gas
in an oil well when it is shut-in.) or negative (decreasing wellbore storage - e.g.
compression of wellbore fluids).
• Storage Time Constant (Tau) is the time required for 63% of the total change to
occur.
• The easiest way of getting these parameters is by doing Quick Match (refer to Fair’s
paper)
EX 7.12AnalysisAnalysis
• Return to Log-Log plot
• Perform Simulate / Quick Match, Use:
– Central well position (L:L) option
– Cphi = 300 psi
– Tau = 0.06 hr
• Adjust values to obtain best match
• Review Semi-log and Cartesian plots
Example 7
Page 7
Edinburgh Petroleum Services PanSystem User Course
EX 7.13AnalysisAnalysis
EX 7.14Example 7Example 7
END OF EXAMPLE 7
Example 8
Page 1
Edinburgh Petroleum Services PanSystem User Course
EX 8.1Example 8Example 8
Horizontal Well
Oil Reservoir
EX 8.2DataprepDataprep
• Select File Open - Example08.pan
• Select Dataprep - Gauge data & plot rate and
pressure
• Review Well, Layer and Fluid parameters
• This is a constant rate drawdown test of a
horizontal well in an oil reservoir.
Example 8
Page 2
Edinburgh Petroleum Services PanSystem User Course
EX 8.3AnalysisAnalysis• Select Analysis - Plot
– Test Overview
– Select the darwdown test period for analysis
– Log - Log plot
• Select model: Two no flow boundaries-homogeneous
• Select FR and identify flow regimes
– Wellbore storage
– Vertical Radial Flow
– Linear Flow through Reservoir
– Late Time Radial Flow
• Confirm results
EX 8.4AnalysisAnalysis
Vertical
Radial flow
Linear flow
through
reservoir
Late time
Radial flow
Example 8
Page 3
Edinburgh Petroleum Services PanSystem User Course
EX 8.5AnalysisAnalysis
Vetical Radial flow
• Is a function of:
Horizontal permeability
Vertical permeability
Provides the average permeability, kbar
Top boundary
Bottom boundary
EX 8.6
Linear flow through reservoir
• Is a function of:
Horizontal permeability
Effective horizontal length
Provides the effective horizontal length if the
horizontal permeability is know.
AnalysisAnalysis
Example 8
Page 4
Edinburgh Petroleum Services PanSystem User Course
EX 8.7
Late time Radial flow/Pseudo-Radial flow
• Is a function of:
Horizontal permeability
Effective net thickness
Provides the thickness-permeability product and
therefore the horizontal permeability.
AnalysisAnalysis
EX 8.8AnalysisAnalysis
Semi log plot:
• Examine 1st (vertical) radial flow
• Examine 2nd (horizontal) radial flow
• Note:
– 1st line gives average permeability
– 2nd line gives horizontal permeability,
& by inference vertical permeability.
• Select each line and use LR button to view
further line results
• Confirm Results
Example 8
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Edinburgh Petroleum Services PanSystem User Course
EX 8.9AnalysisAnalysis
Vertical radial
flow best fit line
Pseudo-Radial
flow best fit line
EX 8.10AnalysisAnalysisLinear plot:
• Examine linear flow period line
• Confirm Results
Log-Log plot:
• Select Simulate - Quick Match
– Fine tune the parameters to get the best match
– Review Cartesian, Semilog , Linear flow plots
– Tile
Example 8
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Edinburgh Petroleum Services PanSystem User Course
EX 8.11AnalysisAnalysis
EX 8.12AnalysisAnalysis
Type Curve Matching:
• Click on “TC”
• Click on “M”
Fixed Well Length:
The user should
define the well length
and use type curve to
get the well position
with respect to the top
boundary.
Unknown Well Length:
The user should define the
well position and use type
curve to get the well length.
Use unknown well length for this example, well position is 0.5
Example 8
Page 7
Edinburgh Petroleum Services PanSystem User Course
EX 8.13AnalysisAnalysis
• Choose curve no. 8
• Go to the next stage of TC to get WBS and S
• Confirm results
• Do QM to fine tune the parameters
EX 8.14ResultsResults
• Cs = 0.0015 bbl/psi
• K = 1.08 md
• Kz = 0.95 md
• S = 0
• Zwd = 0.5
• Lw = 1000 ft
• Pi = 5000 psia
Final Analysis Parameters:
Example 8
Page 8
Edinburgh Petroleum Services PanSystem User Course
EX 8.15Example 8Example 8
END OF EXAMPLE 8
Example 9
Edinburgh Petroleum Services PanSystem User
Course
Page 1
Example 9Example 9
Partial Penetration
Rev 0 1-Nov-06
2
Partial penetration modelPartial penetration model
hp
htop
h
Example 9
Edinburgh Petroleum Services PanSystem User
Course
Page 2
3
Radial flow in full thickness
khp
S = true skin factor
kh
Spr= pseudo-radial
skin factor
Radial flow at perforations
Partial penetration modelPartial penetration model
4
ObjectivesObjectives
Identify model
Reservoir permeability k
True (mechanical) skin factor S
Effective open interval hp
Position of open interval htop
Vertical permeability kz
Effective skin factor Spr
Well productivity
Example 9
Edinburgh Petroleum Services PanSystem User
Course
Page 3
5
Partial PenetrationPartial Penetration
File: example 9_1.pan
This is buildup test in an oil producer
Review well, layer and fluid data
Review pressure data and rate history
The well was perforated over 200 ft of the 382 ft
formation thickness
Top of perfs was 80 ft from the formation top
6
Analysis on the logAnalysis on the log--log plotlog plot
Identify the probable flow regimes from the
derivative
Select the Partial penetration model
Obtain k from the late radial flow regime. Confirm.
Fit the radial ‘FR’ markers to get an estimate of the
pseudo-radial skin factor Spr
Fit a line to the (approx) ‘radial flow at perforations’ portion
(enter nominal hp at the prompt). Note ‘kp’.
Fit the ‘FR’ markers this regime to get an estimate
of the true skin factor S. Confirm.
Note S << Spr
Example 9
Edinburgh Petroleum Services PanSystem User
Course
Page 4
7
W ellbore storage looks very non-ideal… .
Spherical flow did not develop fully
A very rough estimate of kz can be obtained by marking the transition period with the ‘Spherical flow’ FR marker and going to the spherical flow plot.
Alternatively, get it by trial and error with Quick Match
Analysis on the logAnalysis on the log--log plotlog plot
8
Run Quick Match
Clear the lines and ‘FR’ markers (optional)
Refine the match (manually or with Auto Match)
The wellbore storage cannot be matched, even with a varying wbs
model –best to ignore
it !
Note hp is close
to the design
perforated
interval length
Check the
match on all
plots
Analysis on the logAnalysis on the log--log plotlog plot
Example 9
Edinburgh Petroleum Services PanSystem User
Course
Page 5
9
DeliverabiltyDeliverabilty
Select ‘Deliver’ –‘IPR’
Your k and a
computed value
of Spr will be displayed
Enter the estimated
layer pressure and a
bubble point pressure
Use default A and CA
Calculate
Compare with the
productivity index
calculated from the
production rate and final
measured flowing pressure
10
Analysis using specialised plotsAnalysis using specialised plots
Clear Quick Match. Refit the ‘FR’ markers
Go to the Semi-log (Horner) Plot to obtain k, S, kp, Spr
and p*
ConfirmRadial flow at
perforations
Radial flow in
full thickness
Example 9
Edinburgh Petroleum Services PanSystem User
Course
Page 6
11
Fit a line to the (quasi-)spherical flow portion on the
reciprocal square-root plot to obtain kz from the slope
Confirm
Analysis using specialised plotsAnalysis using specialised plots
12
Run Quick Match to refine the results manually, or use
Auto Match
Check the final match on all plots
Analysis using specialised plotsAnalysis using specialised plots
Example 9
Edinburgh Petroleum Services PanSystem User
Course
Page 7
13
Analysis by typeAnalysis by type--curve matchingcurve matching
Clear Quick Match and go to the Type-Curve section
Select the default Partial Penetration type-curves
Match the
derivative
Use the arrowkeys for fineadjustment
Confirm results
14
Click the right arrow button to move to the next
matching stage (optional)
Match the storage-dominated portion of the pressure and
derivative to
obtain Cs and S
The match is poor
owing to the non-
ideal nature of the
wellbore storage
Confirm results
Refine match using
Quick Match or Auto
Match
Analysis by typeAnalysis by type--curve matchingcurve matching
Example 9
Edinburgh Petroleum Services PanSystem User
Course
Page 8
15
GasGas--cap modelcap model
Change the model to Gas-cap/Aquifer support
The input parameters are the same, but the top of the reservoir is
now a
constant pressure
boundary
Run Quick Match
Note how we no
longer see any
late radial flow
regime
W ith stronger well-
bore storage, the
test might yield no
useful information…
16
Alternative slant well modelAlternative slant well model
Return to the log-log plot
Select the Slanted well model
This is a partial penetration model that allows for well
deviation
The input parameters are defined differently (see Help)
Run Quick Match with the same parameters (redefined) as your
previous analysis:
ANG=0°
ZWDT = htop/h
ZWDB=(htop+hp)/h
RKZR=kz/k
IBDY=1 (no-flow boundary above and below)
Example 9
Edinburgh Petroleum Services PanSystem User
Course
Page 9
17
These parameters are equivalent to those derived in the
Log-log plot section
Alternative slant well modelAlternative slant well model
18
This model is stable with the varying wbs models, but it
is still not possible to match the derivative… .
Alternative slant well modelAlternative slant well model
Example 9
Edinburgh Petroleum Services PanSystem User
Course
Page 10
19
Derivative Diagnostic LibraryDerivative Diagnostic Library
Edinburgh Petroleum Services PanSystem User Course
Page 1
Example 10
EX 10.1Example 10
Radial Composite
Reservoir
EX 10.2DataPrep• Start PanSystem
• Open file Exampl10.pan
• In DATAPREP
– Review Well, Layer and Fluid data
– Review Gauge data and Production
History (Rate changes)
• Plot pressure data including rate
changes
Edinburgh Petroleum Services PanSystem User Course
Page 2
Example 10
EX 10.3• This is a Fall-Off test for a Water Injection
well in an oil reservoir
• The Inner zone fluid properties should be used for the analysis
• The injection rate is defined by a negative number
• In this type of tests there are at least two radial regions:
– Inner zone - Water bank
– Outer zone - Oil bank
DataPrep
EX 10.4• ANALYSIS-PLOT
– Test Overview
– Select Fall-Off Test Period
– Log-Log plot
• Radial Composite behaviour on the derivative
• The mobility in the inner zone is higher than the mobility in the outer zone
• Select Analysis-Model and choose RadialComposite flow model
• Review the model parameters
Analysis
Edinburgh Petroleum Services PanSystem User Course
Page 3
Example 10
EX 10.5Analysis
Lrad is the outer radius
of the inner zone or inner
radius of the outer zone
(Distance to a radial
discontinuity).
M is the outer/inner
Mobility ratio
(k/ )outer/ (k/ )inner
w is the outer/inner
Stortivity ratio
( Ct)outer/( Ct)inner
EX 10.6Analysis• On the Log-Log plot define all the relevant flow
regimes:
Wellbore
Storage effect
Inner zone
radial flow
Outer zone
radial flow
Edinburgh Petroleum Services PanSystem User Course
Page 4
Example 10
EX 10.7Analysis• Confirm the results on the Log-Log plot and go to
Semi-Log plot
• Select each line and check the line results
• Confirm results
There is no analysis
procedure to get an
initial estimate for w. the
best way is to start with
w=1.0 and then use
QM/AM to find the final
value. So it is a matching
parameter.
Lrad is a function of the
intersection time of
these two straight lines.
EX 10.8Analysis• Go back to Log-Log plot
• Use Quick Match (QM) or Auto Match (AM)
• Fine tune the analysis parameters
Edinburgh Petroleum Services PanSystem User Course
Page 5
Example 10
EX 10.9Example 10Example 10
END OF EXAMPLE 10
Example 11
Edinburgh Petroleum Services PanSystem User Course
Page 1
Example 11Example 11
Vertically fractured
well
Rev 0 1-Nov-06
2
wellfracture
k
kfbf
xf
“Infinite Conductivity”is a valid assumption if
the quantity 300f
ffCD
xk
bkF
Vertical fracture modelsVertical fracture models
h
Full-height
fracture
xf
Example 11
Edinburgh Petroleum Services PanSystem User Course
Page 2
3
Fracture face skin Fracture face skin SfSf
Sfrepresents an altered region of reduced
permeability ka and thickness ba, caused by frac
fluid invasion
It introduces an additional pressure drop between
reservoir and wellbore
Sfis usually a small number (< 1), but it acts over
a very large surface area (4xhxXf).
Fracture
ba
ka
4
ObjectivesObjectives
Determine type of fracture model
Reservoir permeability (if possible)
Fracture half-length Xf
Fracture quality:
conductivity kfw
fracture face skin factor Sf
Effective skin factor Spr
W ell productivity/injectivity
Example 11
Edinburgh Petroleum Services PanSystem User Course
Page 3
5
Infinite Conductivity FractureInfinite Conductivity Fracture
File: example 11_1.pan
This is a simulated water injection fall-off test
Review well, layer and fluid data
Review pressure data and rate history
W ater is being injected from surface:
Note PVT calculated at injection temperature, not at
reservoir temperature
Note Sw=1, not default zero
The well was not hydraulically fractured
6
Analysis from logAnalysis from log--log plotlog plot
Identify the probable flow regimes from the
derivative
Select the Infinite conductivity fracture model
Obtain k (approximate) from the late radial (almost!) flow
regime. Confirm.
This can be refined later by simulation
Fit the radial ‘FR’ markers to get an estimate of the
pseudo-radial skin factor Spr
Obtain fracture half-length Xf.
Example 11
Edinburgh Petroleum Services PanSystem User Course
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7
There is no unit slope so Cs cannot be derived from a line-fit
Check the relationship between Spr and Xf:
rweff = ½Xf = rw.e–Spr
Analysis from logAnalysis from log--log plotlog plot
8
Run Quick Match
Clear the lines and ‘FR’ markers
Refine the match (manually or with Auto Match)
Analysis from logAnalysis from log--log plotlog plot
Example 11
Edinburgh Petroleum Services PanSystem User Course
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Analysis from specialised plotsAnalysis from specialised plots
Clear Quick Match
Fit a line to the radial flow portion on the Semi-log
(Horner) Plot to
obtain k, Spr and p*
Confirm
Since radial flow
did not develop
fully, these results
will be approximate.
10
Fit a line to the linear flow portion on the square-root plot
to obtain Xf (slope) and Sf (intercept)
Confirm
Analysis from specialised plotsAnalysis from specialised plots
Example 11
Edinburgh Petroleum Services PanSystem User Course
Page 6
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Run Quick Match to refine to results manually, or use
Auto Match
Negative Sf is not allowed in Quick match
Check the final match on all plots
Analysis from specialised plotsAnalysis from specialised plots
12
Analysis by typeAnalysis by type--curve matchingcurve matching
Clear Quick Match and go to the Type-Curve section
Match pressure and derivative
Confirm results
Refine match
using Quick Match
or Auto Match
Example 11
Edinburgh Petroleum Services PanSystem User Course
Page 7
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Note that a good estimate of k can be obtained by
matching to the derivative shape even if radial flow has
not fully developed
In the absence of any transition from linear to radial flow
(test too short), an independent estimate of k (pre-frac
test, core data, other welltests) will be needed
Uniform Flux Fracture model
Go to the log-log plot, switch model to ‘Uniform flux
fracture’
Run Quick Match to compare the two models.
Analysis by typeAnalysis by type--curve matchingcurve matching
14
Class exampleClass example
File: example 11_2.pan
This is a real water injection fall-off test
Review well, layer and fluid data
Review pressure data and rate history
W ater is being injected from surface
The well was not hydraulically fractured
Example 11
Edinburgh Petroleum Services PanSystem User Course
Page 8
15
Data Edit PlotData Edit Plot
This file was set up with a rate change marker
positioned at the time when
the gauge was put on-depth
There is no need to
mark this point, but it does
no harm… ..
The important thing is to
specify the injection
history correctly
Gauge on-depth
Gauge
RIH
16
AnalysisAnalysis
Analyse the data in the same way as the previous
example (choose your favourite method… )
Use Quick Match to refine the parameters
Try a varying
wellbore storage
model to improve
the early match…
Example 11
Edinburgh Petroleum Services PanSystem User Course
Page 9
17
AnalysisAnalysis
There are two unexplained glitches in the derivative
One of them might be
explained by the well
“going on vacuum”
W ellhead pressure falls
below atmospheric, causing
water to vaporise
Can be matched (approx)
using ‘Time-stepped wbs’
model
18
Deliverabilty/InjectivityDeliverabilty/Injectivity
Select ‘Deliver’ –‘IPR’
Switch on the ‘Injection well’ box
Your k and a
computed value
of Spr will be displayed
Enter the estimated
layer pressure
Use default A and CA
Calculate
Compare with
injectivity index from
Injection Test Data (injection rate and final measured
injection pressure)
Example 11
Edinburgh Petroleum Services PanSystem User Course
Page 10
19
Finite Conductivity FractureFinite Conductivity Fracture
File: example 11_3.pan
This is another water injection fall-off test
Review well, layer and fluid data
Review pressure data and rate history
W ater is being injected from surface
The well has been hydraulically fractured
20
Analysis from logAnalysis from log--log plotlog plot
Fit lines –possible model?
Zero-slope (radial flow) not developed
1-slope
½-slope
0-slope?
¼-slope
?
Example 11
Edinburgh Petroleum Services PanSystem User Course
Page 11
21
Analysis from logAnalysis from log--log plotlog plot
Identify the probable flow regimes from the
derivative
Select the Finite conductivity fracture model
Obtain k (an upper limit) from the trend towards late
radial flow regime. Confirm.
o This can be refined later by simulation
Fit the radial ‘FR’ markers to get an estimate of the
pseudo-radial skin factor Spr
No other line calculations are made (yet) on the log-log
plot for this model, so we will use the diagnostic plots… .
22
Linear flow plotLinear flow plot
Line-fit to linear flow regime gives Xf and, for the
finite conductivity model, FCD (instead of Sf)
Confirm in order initialise Spr
Example 11
Edinburgh Petroleum Services PanSystem User Course
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23
BiBi--linear flow plotlinear flow plot
Line-fit to bi-linear flow regime gives FCD from
slope
24
Run Quick Match to refine the results manually, or use
Auto Match
Check the final match on all plots
W hat is the significance of the negative Pi ?
Negative Pi!
Example 11
Edinburgh Petroleum Services PanSystem User Course
Page 13
25
Pseudo-radial flow did not have time to develop
W e have just the beginning of the transition from linear flow towards
radial (and the data are noisy!)
This is enough to give us a rough fix on permeability, but
there will be a range of uncertainty:
Experiment with Auto Match by trying fixed k values between, say,
0.1 md and 1.4 md, to see what range it could take
Use the ‘goodness of match’, and your eye, to judge what is an
acceptable match
Note the corresponding uncertainty in FCD and Xf
26
Analysis by typeAnalysis by type--curve matchingcurve matching
Clear Quick Match and go to the Type-Curve
section
Select the default finite conductivity type-curve set
Match pressure
and derivative to
obtain k, Xf and FCD
The picture shows
a reduced TC set
with FCD from 5 to 30
Confirm results
Use the TC filter to eliminate
unwanted curves
Example 11
Edinburgh Petroleum Services PanSystem User Course
Page 14
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Analysis by typeAnalysis by type--curve matchingcurve matching
Click the right arrow button to move to the next
matching stage
Match the storage-dominated portion of the pressure and
derivative to
obtain Cs and Sf
Confirm results
Refine match using
Quick Match or Auto
Match
28
Class exampleClass example
File: example 11_4.pan
This is buildup test in an oil producer
The well has been hydraulically fractured
Review well, layer and fluid data
Review pressure data and rate history
Example 11
Edinburgh Petroleum Services PanSystem User Course
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29
AnalysisAnalysis
Analyse the data in the same way as the previous
example
Use Quick Match to refine the parameters
30
Derivative Diagnostic LibraryDerivative Diagnostic Library
Example 11
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31
Example 12
Page 1
Edinburgh Petroleum Services PanSystem User Course
EX 12.1Example 12Example 12
Gas Well Testing
EX 12.2OverviewOverview
• This example explains the Gas welltest analysis
workflow
• It is a DST test in a gas well
– Analyse Initial BU - reservoir pressure
– Analyse Final BU - reservoir parameters
– Analyse Flow-After-Flow for Darcy and Non-
Darcy skin factors
• Verify / Refine complete test sequence
• Calculate Deliverability
• Perform LIT and C&n analysis
Example 12
Page 2
Edinburgh Petroleum Services PanSystem User Course
EX 12.3DataprepDataprep• Run PanSystem
• FILE - OPEN Example12.pan
• DATAPREP-GAUGE DATA Plot pressure data
• Note the sequence of flowrates which represents a complete
DST in a gas well.
EX 12.4DataprepDataprep• Dataprep - Well and Reservoir Parameters
(Analytical…)
• Note that the fluid type is gas and the well is vertical
• Select the layer parameters
Note that the Layer Pressure and
Layer Temperature are required
as the reference gas properties
have been computed at this
condition. It is mandatory for
analysis of gas wells.
Example 12
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Edinburgh Petroleum Services PanSystem User Course
EX 12.5• Set model to Radial Homogeneous and Infinite Acting
and check the model parameters
• Note that there is a non-Darcy skin parameter for gas
wells which should be determined from the analysis.
DataprepDataprep
Non-Darcy skin is the pressure drop due to turbulence effect. Near
the wellbore the gas velocity is quite high therefore the flow behaviour
is turbulent flow which causes more pressure drop compared with
Darcy flow. It is a function of rock and fluid properties.
EX 12.6• Select the fluid parameters button
– The gas specific gravity is the main parameter required:
–Input this parameter directly or
–Use Gas composition and EOS to calculate it
– Use Gas Composition... button and input the following composition:
– Use Calculate button to calculate gas SG
DataprepDataprep
N2 H2S CO2 C1 C2 C3 iC4 nC4 iC5 C6 C7+ MwC7+
1.17 0.0 1.54 76.8 8.82 3.2 0.49 1.14 0.42 0.57 5.11 100.2
Example 12
Page 4
Edinburgh Petroleum Services PanSystem User Course
EX 12.7DataprepDataprep
Normalising the
composition if the sum
is not 100%
Note that Schmidt-Wenzel
EOS is implemented in PS to
calculate the gas SG.
EX 12.8
• Tick the EOS option and use the appropriate gas viscosity correlation
• Review pseudo-pressure table
• Check Analysis-Pressure Transformation...
DataprepDataprep
This button
calculates
individual
selected table
This button
calculates all table
Example 12
Page 5
Edinburgh Petroleum Services PanSystem User Course
EX 12.9AnalysisAnalysis• ANALYSIS-PLOT
– Test Overview
– Select the first Build-up Test Period
– Semi-Log plot:
• Select TWO points on the radial flow regime, note that the radial flow is not fully developed.
• Use best fit line - Radial Flow
• Make note of the Extrapolated Pressure, P*
EX 12.10AnalysisAnalysis
Example 12
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Edinburgh Petroleum Services PanSystem User Course
EX 12.11AnalysisAnalysis• Go back to Test Overview
• Select the Final BU and go to Log-Log plot
• Not considerable WBS effect
• Define Radial Flow regime and go to Semi-Log plot
• Confirm results
EX 12.12AnalysisAnalysisNon-Darcy Skin Calculation
• Return to Test Overview and click on the ruler bar to
select the first of the drawdowns following the first BU
• Hold down the Ctrl key and click on the other three
drawdowns to select all the periods in the flow-after-
flow test
• Perform Semi-Log plot
• There should be a line automatically on this plot
• Use the mouse right click to activate this line
• Adjust the slope to get the same permeability as the one
from final BU analysis (3.3 mD)
Example 12
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Edinburgh Petroleum Services PanSystem User Course
EX 12.13AnalysisAnalysis
Non-Darcy Skin Calculation
• Move this line to fit the radial flow of Test Period 1
(TP1)
• Use Parallel line button to fit parallel lines through
other test periods
• Perform Analysis Non-Darcy Skin Analysis
• Re-assign the type of each lines to its appropriate test
period
EX 12.14AnalysisAnalysis
Example 12
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Edinburgh Petroleum Services PanSystem User Course
EX 12.15AnalysisAnalysis• The Skin vs Rate button is active now
• Use this button to get S vs Q plot
• Select first and last points
• Use best fit line button to get the damage skin and Non-Darcy
skin coefficient
• Confirm results
F is Non-Darcy
flow coefficient
EX 12.16AnalysisAnalysis• Full Test Match and Verification:
– Perform Test Overview
– Select Analysis, Model, Model Parameters and change the
initial wellbore pressure to the extrapolated pressure from
the initial buildup.
– Simulate Quick Match note the poor quality of the match
at the initial buildup and at late time data.
– Change the initial wellbore pressure as above to 7150 psi
and repeat the simulation
– The data still does not match
– The simulated pressure is much higher than the observed
data - we must have some material balance / boundary
effect causing this
– Add boundaries - Single fault and simulate again
Example 12
Page 9
Edinburgh Petroleum Services PanSystem User Course
EX 12.17Final ResultsFinal Results
EX 12.18LIT AnalysisLIT Analysis
• Relationship between flowing pressure and
flow rate:
kh
TDF
SrC
A
kh
TB
where
FQBQpmpmie
DQSrC
A
kh
QTpmpm
wA
wf
wA
wf
1422
4ln
2
11422
)()()(
4ln
2
11422)()(
2
2
2
Example 12
Page 10
Edinburgh Petroleum Services PanSystem User Course
EX 12.19LIT AnalysisLIT Analysis• Click on the ruler bar to select the first drawdown of
the FAF test.
• Hold down Ctrl and click on the other flow periods
to select all of the other drawdown periods.
• Click on the LIT toolbar icon, select Flow-After-
Flow and review the tabular data
EX 12.20
• Click on OK and draw a line on the plot, ‘best fit’
through the points
• Confirm the results
LIT AnalysisLIT Analysis
Example 12
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Edinburgh Petroleum Services PanSystem User Course
EX 12.21DeliverabilityDeliverability
• Select Deliver - IPR
• Click on calculate
• Click on OK
• Click on T/L Lin
button to see the
Transient and LIT
results on the same
plot
• Repeat the above
exercise for the C&n
Analysis
You can generate up to 5
IPR curves for different
cases.
EX 12.22DeliverabilityDeliverability
Example 12
Page 12
Edinburgh Petroleum Services PanSystem User Course
EX 12.23Example 12Example 12
END OF EXAMPLE 12
Example 13
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Edinburgh Petroleum Services PanSystem User Course
EX 13.1Example 13Example 13
Gas Well Testing:
Isochronal Test
EX 13.2OverviewOverview
• Use Transient analysis to give Damage and
Rate Dependent Skin factors
• Generate Deliverability from transient results
• Use LIT or C&n analysis for Deliverability
alone
• Compare different deliverabilities
Example 13
Page 2
Edinburgh Petroleum Services PanSystem User Course
EX 13.3DataprepDataprep
• Load EXAMPLE13.PAN
• Review input data in Dataprep
• Plot pressure and rate
• This is an Isochronal test in a dry gas reservoir.
EX 13.4Transient AnalysisTransient Analysis
• Select Analysis - Plot
• Select all the drawdowns (excluding the
extended drawdown at the end)
• Perform Semilog plot
• Draw parallel lines through the different
flow periods (Try K = 1.28 md)
Example 13
Page 3
Edinburgh Petroleum Services PanSystem User Course
EX 13.5Transient AnalysisTransient Analysis
EX 13.6• Select Analysis - Non Darcy Skin Analysis
• Confirm each line as Radial flow line for each test period
• Perform S vs. Q plot
• Draw line and confirm results
Transient AnalysisTransient Analysis
D = Slope
S = Intercept
Note that F is
non-Darcy flow
coefficient.
Example 13
Page 4
Edinburgh Petroleum Services PanSystem User Course
EX 13.7
• Return to Semilog plot
• Select Analysis - Correct for Rate Dependency
• Return to Test Overview and select the buildups
• Repeat the above exercise
Transient AnalysisTransient Analysis
EX 13.8
TransientTransient
DeliverabilityDeliverability
• Select Deliver - IPR
• Review data and
calculate transient
deliverability
• Click OK to get the
IPR plot
Use these arrows to compare up to
5 IPR curves.
Example 13
Page 5
Edinburgh Petroleum Services PanSystem User Course
EX 13.9LIT AnalysisLIT Analysis
FQBQ
pmpm
FQBQpmpm
wf
wf
)()(
)()()( 2
kh
TDF
SrC
A
kh
TB
wA
1422
4ln
2
114222
F is independent of reservoir volume and shape
EX 13.10LIT AnalysisLIT Analysis
• Select Analysis - Plot
• Select all the drawdowns (including the
extended drawdown at the end)
• Use LIT button, choose Isochronal and review
input data
Example 13
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Edinburgh Petroleum Services PanSystem User Course
EX 13.11LIT AnalysisLIT Analysis• Plot data, and fit free model line through short
drawdown points
• Fit a parallel line through extended flow point
• Confirm results
F = Slope
B = Intercept
EX 13.12LIT AnalysisLIT Analysis
• Select Deliver - IPR again
• Plot IPR and compare with transient IPR
Transient IPR
LIT IPR
Example 13
Page 7
Edinburgh Petroleum Services PanSystem User Course
EX 13.13C & n AnalysisC & n Analysis
Repeat the LIT exercise for C&n analysis.
intercept theislog1
andslope theis1
log vs)log(
log1
log1
)log(
)log(loglog
)C(Q
22
res
22
res
22
res
22
res
Cnn
Qppplot
Cn
Qn
pp
ppnCQ
pp
j
j
j
n
j
EX 13.14Example 13Example 13
END OF EXAMPLE 13
Example 14
Page 1
Edinburgh Petroleum Services PanSystem User Course
EX 14.1Example 14Example 14
Advanced Simulation
EX 14.2OverviewOverview
• Analyse Exampl14.PAN (already
prepared) to obtain estimate of reservoir
parameters
• Set up Start Pressures for simulation
• Perform simulation
• Compare with test data
• Correct reservoir parameters and
simulate again...
Example 14
Page 2
Edinburgh Petroleum Services PanSystem User Course
EX 14.3AnalysisAnalysis
Analyse final build-up:
• Define wellbore storage flow regime and
confirm Cs
• Define flow regime for radial flow on log-log
plot
• Examine Semilog plot, skin estimation
• Confirm the permeability and skin factor
• Note the Extrapolated pressure
EX 14.4
AdvancedAdvanced
SimulationSimulationQuick Match starts the pressure calculation
at the start of the test period being analysed.
Example 14
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Edinburgh Petroleum Services PanSystem User Course
EX 14.5
AdvancedAdvanced
SimulationSimulationAdvanced Simulation always starts the pressure
calculation at the start of the first test period
The user can Save, Analyse, Report, etc… theAdvanced Simulation results but not the Quick Match results.
EX 14.6
AdvancedAdvanced
SimulationSimulation• Advanced Simulation allows the user to model
a start pressure in the wellbore and a start
pressure in the layer
• The layer pressure is entered in the layer
parameters screen
• The wellbore pressure is the pressure associated
with the first rate change
• Go back to dataprep and check this values.
• If you do not have a good value then enter the
extrapolated pressure from the semilog plot.
Example 14
Page 4
Edinburgh Petroleum Services PanSystem User Course
EX 14.7
AdvancedAdvanced
SimulationSimulationSelect Simulate - Advanced Simulation option:
Select input
Rate Channel
Enter individual
column names in
output data file
Select Solution
Model, TCX file,
for look-up Pd
calculations
Select speed option
EX 14.8
AdvancedAdvanced
SimulationSimulationDataprep - Gauge Data:
The output data file will now have three extra
columns:
–simulated pressure
–calculated total down hole rate
–calculated layer rate
Example 14
Page 5
Edinburgh Petroleum Services PanSystem User Course
EX 14.9
AdvancedAdvanced
SimulationSimulation
Compare the test data with the simulated data:
• Plot them together in Dataprep - Gauge Data
or
• Go to Analysis - Plot
• Use the Edit-Overlay Pressure... option to
display calculated pressure on the same plot.
(This can be done on Cartesian, Semilog, Log-
Log etc... plots as well)
EX 14.10
AdvancedAdvanced
SimulationSimulation
Example 14
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Edinburgh Petroleum Services PanSystem User Course
EX 14.11
Summary of Summary of
ResultsResults
A good match can be obtained with:
Cs = 0.023 bbl/psia
K = 80 md
S = - 0.35
EX 14.12Example 14Example 14
END OF EXAMPLE 14
Example 15
Page 1
Edinburgh Petroleum Services PanSystem User Course
EX 15.1Example 15Example 15
Test Design
EX 15.2OverviewOverview• Set up reservoir data for the test design
• Set up initial test design
• Calculate pressure based on initial test
design
• Analyse calculated pressure and check if
pressure behaviour meets test objectives
• Investigate if the fault seen on the seismic
map is sealing
Example 15
Page 2
Edinburgh Petroleum Services PanSystem User Course
EX 15.3Model PreparationModel Preparation
Build the simulation model:
• Initialise the system with File-New
• Ensure the fluid type is Oil (Single Phase)
• Ensure the well orientation is vertical
• Ensure there is only one well and one layer
EX 15.4Model PreparationModel Preparation
• Enter the well data
– Rw = 0.35 ft
– Cs = 0.01 bbl/psi
• Enter the layer data
– h = 100 ft
– = 0.2
– Po= 5000.0
• Flow model should be Radial Homogeneous
• Enter the model parameters
– k = 91mD
– S = 2.3
Example 15
Page 3
Edinburgh Petroleum Services PanSystem User Course
EX 15.5Test DesignTest Design
• Enter the fluid parameter data
– Bo = 1.1
– Uo = 0.7
– Ct = 1.0e-5
• Set up boundary data
– Set boundary model to single fault, seen on the
seismic map
– L = 250.0 ft
– Calculate image wells
EX 15.6Test DesignTest Design
Set up the test design:
• Select Dataprep - Gauge Data
• Test Design
• Enter the following test periods
– t = 10.0, q = 200.0, steps = 50, format = 2
– t = 20.0, q = 0.0, steps = 50, format = 2
• Enter a wellbore pressure = 5000.0 psia
Example 15
Page 4
Edinburgh Petroleum Services PanSystem User Course
EX 15.7Test DesignTest Design
• Perform advanced simulation
• Analyse the results:
– Check the build-up on the log-log plot to see if we
have met the test design objective(s)
• Results:
– Wellbore storage slightly obscures radial flow
– We can only see the start of the doubling of the
semilog slope due to the single fault
EX 15.8
Start of
Boundary effect
Test DesignTest Design
Example 15
Page 5
Edinburgh Petroleum Services PanSystem User Course
EX 15.9Test DesignTest Design
Let’s try again...
• Delete the previous test design data “file”
• Set up another test design extending the length of the
build-up
– t = 10.0, q = 200.0, steps = 50, format = 2
– t = 110.0, q = 0.0, steps = 50, format = 2
• Proceed as before
• Check the log-log plot of the build-up
• No change - it is the time of the draw-down that dictates
how far we see into the reservoir
EX 15.10Test DesignTest DesignLet’s try again...
• Delete the previous test design data “file”
• Set up another test design extending the length of
the drawdown as well
– t = 100.0, q = 200.0, steps = 50, format = 2
– t = 200.0, q = 0.0, steps = 50, format = 2
• Proceed as before
• Check the log-log plot of the build-up
• Better - now we can see the beginning of the
second radial flow regime
• Complete the analysis to obtain k, S, & L
Example 15
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Edinburgh Petroleum Services PanSystem User Course
EX 15.11Test DesignTest Design
EX 15.12Test DesignTest Design
Let’s repeat the test with downhole shut-in.
• Do NOT delete the previous test data “file”
• Change wellbore storage to 0.001 bbl/psi
• Simulate as before, but give new names to the
simulation results channels (“pressure1”, etc)
• Check the log-log plot of the build-up
• Do the analysis again to obtain k, S, & L
• Use Edit-Overlay Pressure to compare with high
storage case
Example 15
Page 7
Edinburgh Petroleum Services PanSystem User Course
EX 15.13Test DesignTest Design
Conclusions
• A 100 hour drawdown followed by a 100
hour buildup will define system (with a
little error).
• Wellbore storage needs to be reduced as
possible (downhole shut-in?), for more
accurate results.
EX 15.14Example 15Example 15
END OF EXAMPLE 15
Example 16
Page 1
Edinburgh Petroleum Services PanSystem User Course
EX 16.1Example 16Example 16
Interference Test
Design
EX 16.2
To design a pressure interference test using
PanSystem, it is necessary to define:
– Wells
– Layer and Fluids description
– Flow Rates
– Advanced Simulation Parameters
In designing, it is necessary to have the reservoir
parameters and a specific sequence of flowrates to
generate the pressure response.
Example 16
Example 16
Page 2
Edinburgh Petroleum Services PanSystem User Course
EX 16.3Interference TestInterference Test
The objectives of this example are:
• To build a model to handle the interference
between two wells, a Producer and an
Observation.
• Investigate the pressure behaviour in the
producer well.
• Analysing observed pressure using available
type curve.
EX 16.4Well DefinitionWell Definition• Initialize the system with File-New
• Select DataPrep and Reservoir Description
• Select type of fluid Oil and well Vertical
• Use the option Add well... and change the name
to Observer.
• Select Well-1 and change the name to :
Producer.
• The producing well is preceded by the letter P-
that means it is the principal well and is always
located at the coordinates (0,0).
Example 16
Page 3
Edinburgh Petroleum Services PanSystem User Course
EX 16.5Well ParametersWell ParametersFor the producing and
observation wells use:
• Well radius 0.3 ft.
• Storage 0.01 bbl/psi
The coordinates of the
observation well are (0,
2500), this means that it is
on the y-axis.
EX 16.6Layer DescriptionLayer Description
• Select Layer Parameters and input:
• Layer thickness 25 ft.
• Porosity 0.20
• Layer pressure 4000 psia
• Temperature 200 F.
• Choose Radial Homogeneous model and use the
following values
• Permeability: 250 mD
• Skin Factor : Producing well: 5
Observation well : 0
Example 16
Page 4
Edinburgh Petroleum Services PanSystem User Course
EX 16.7Fluids DescriptionFluids Description
• Select Fluid Parameters and input the
values:
• Oil Formation Volume Factor, Bo : 1.3
• Oil Viscosity, uo : 2.5 cp
• Total Compressibility : 1e-5 (1/psi)
EX 16.8TestTest flowratesflowratesSelect DataPrep and Gauge Data
• Flow rates are defined for the Principal well (i.e.
producing well in this case)
• Make sure to select the Producing well in the Well to
Edit dialog box
• Select the option Test Design and input the following
two flow periods as shown in the graph below:
Example 16
Page 5
Edinburgh Petroleum Services PanSystem User Course
EX 16.9• Select the Observation well in the Well to Edit
dialog box
• Select the option Test Design
• Reply No. to use the principal well times for the
Observation well
• Input the following two flow periods as shown in
the graph below:
TestTest flowratesflowrates
EX 16.10
AdvancedAdvanced
SimulationSimulation• Select Simulate - Advance Simulation...
• Everything is ready to run Advanced Simulation.
Do Not change controls such as:
– flow rates
– name of the generated columns
– observation points
– speed
• Select Ok to run the simulation
• Select DataPrep - Gauge Data
Example 16
Page 6
Edinburgh Petroleum Services PanSystem User Course
EX 16.11AnalysisAnalysis
• For the producing well (Well to edit : Producer)
define the following flow periods
– Start and final points for each period.
– make sure that the pressure, the rate and the
time correspond with the graph
• Proceed to Analysis - Plot of the build up
section.
EX 16.12
Build up Analysis Build up Analysis
Flowing WellFlowing Well
Example 16
Page 7
Edinburgh Petroleum Services PanSystem User Course
EX 16.13
Observation Well Observation Well
AnalysisAnalysis
• Go back to DataPrep- Gauge Data
• In Well to edit dialog box select the Observer well
• Delete SIMULATED Sim Q Total and Sim Q#1
using Delete button
• Select Sim P and Plot
• Define flow periods for this well
EX 16.14
Observation Well Observation Well
AnalysisAnalysis
Example 16
Page 8
Edinburgh Petroleum Services PanSystem User Course
EX 16.15
• Proceed to Analysis - Plot
• Select Observer well for
analysis
• Select the Drawdown test
period and proceed to Type
Curve analysis.
Observation Well Observation Well
AnalysisAnalysis
EX 16.16
Observation Well Observation Well
AnalysisAnalysis
Example 16
Page 9
Edinburgh Petroleum Services PanSystem User Course
EX 16.17Example 16Example 16
END OF EXAMPLE 16
Example 17
Page 1
Edinburgh Petroleum Services PanSystem User Course
EX 17.1Example 17Example 17
Reporting
EX 17.2Example 17Example 17• Load Example07.pan
• Select Report - Configure Report
• Click on Format
• Note the number of pages in each
section
• Select Analysis - Plot
• Select Report - Configure Report
• Click on Format
Note that the report is built up as you create plots and an analysis plot will not
be included unless plotted (it may be omitted by specific de-selection)
Example 17
Page 2
Edinburgh Petroleum Services PanSystem User Course
EX 17.3AnalysisAnalysis• Perform Log-Log plot
• Select Analysis- Model and select
Dual porosity with parallel faults
• Add flow regime markers to the plot
• Select Edit -Description
• Type some text - this ‘Description’ text box
will remain attached to the log-log plot and
will be displayed on the printed report. (it
will also be saved in the .PAN file)
EX 17.4ReportReport
• Select Report / Cover Page
• Type data in some of the requested fields
• Click on Edit - Remarks and type some text
• Return to the log-log plot
• File - Save as - EXAMP17.PAN
• Now exit PanSystem
• Restart Pansystem and load EXAMP17.PAN
• Check the remarks box and note that all of the
report related data has been included in the .PAN
file.
Example 17
Page 3
Edinburgh Petroleum Services PanSystem User Course
EX 17.5ReportReport
• Select Report - Configure Report
• Click on Edit beside the Input
Data line
• Note the various fields which
can be included or not as
required in the report
• Click on other Edit buttons -
review options
• Click on Edit Layout button to
review those settings
EX 17.6ReportReport
• Select Report - Select Report Template
• Note the ability to create, load, edit and save
templates
• Note that the logo used in the reports can be
included or not
• Entering a LOGO.BMP file in the reports
subdirectory will allow the user to include his own
logo.
• A second logo may be used in the report at the
other end of the page header by including a
CLIENT.BMP file in the reports directory
Example 17
Page 4
Edinburgh Petroleum Services PanSystem User Course
EX 17.7Example 17Example 17
END OF EXAMPLE 17
HorizontalWelltest Analysis
Horizontal Welltest Analysis
This example covers the analysis of a horizontal well test. Recorded data comprises only the draw-down period of a well test performed in a low permeability sandstone reservoir producing oil. The method we will follow is:
Shape recognition for horizontal well tests.
Flow regimes selection - Wellbore storage - Vertical radial flow - Linear flow through reservoir - Late time radial flow
Line-fitting
Type curve analysis
Simulation / Auto-regression
2.1 Overview of Horizontal Well Test Response
zw
z w
h
h
x
x
y
y
z
z
Formation Bottom
Formation Top
Fig 13.1.1
Horizontal Well Geometry
In the analytical model we assume that kx=ky
Kbar ( k ) is the average vertical radial permeability ( kzkk . )
Lw is the effective well length (ie: the producing interval)
Zw defines the (average) well position, and ZWD = Zw / h
S is the mechanical or “true” skin factor
Lw
Side View
End View
Pseudoradial
Flow
Linear
FlowRadial Vertical
Flow
FLOW REGIMES
linear
flow
pseudo
radial
flow
plateau
plateau
half slope
no wellbore storage
Fig 13.2.2
Horizontal Well Log-Log Derivative Diagnostic
log p
log t
1
2
3
Well in middle (ZWD=0.5)
RVF
hemi
radial
flow
no wellbore storage
half
slopesecondplateau
firstplateau
Fig 13.2.3
log t
log p
Hemiradial and Linear Flow Diagnostics
log p
Spherical Flow in a Horizontal Wellof Short Length
pseudoradial
flowspherical
flow
negativehalf
slope
RVF
L < h
Fig 13.2.4
2.2 Horizontal Well Test Analysis Workflow
The data file is called HORIZON.PAN. The original gauge data have already been imported, edited, and the rate change events picked graphically (as explained in Example 1 of the on-line Help). All well and reservoir data have been entered and the file saved as a .PAN system file, ready for analysis. This example will review only the horizontal well part of the Well and Reservoir Parameter input. The rest of this type of input is covered (for an oil well) in Example 2 of the on-line Help.
Well offset from middle (ZWD 0.5)
The whole test is shown in Figure 1, (Dataprep, Gauge Data option, Plot button).
Figure 1 - Data Edit Plot The surface flowrate schedule for the test is listed in the Rate Change table (Dataprep, Gauge Data option, Rate changes button).
Figure 2 - Rate allocation
2.2.1 Principal Well Orientation
Select the Dataprep menu, Well and Reservoir Description (Analytical) option and this brings up the Reservoir Description dialog box. Make sure the Principal Well Orientation is checked as Horizontal and the Fluid Type is checked as oil. Click the Layer Parameters button and note that estimates of Formation thickness, Porosity and Total Compressibility have been entered. Note that the ‘Two no-flow boundaries – homogeneous’ model has been selected as Model in the Flow model (horizontal well) section since this is sandstone reservoir with no gas cap. The dialog box appears as shown in Figure 3.
Figure 3 - Layer Parameters Dialog Box
2.2.2 Analysis
The purpose of analysing this draw-down is to get an estimate of the reservoir parameters and the producing (effective) open interval length. You can do your own analysis of the plots for this draw-down. Our interpretations and actions were as follows:
Select Analysis menu option Plot. This displays the Test Overview.
Log-log plot (Fig 4):
- Unit slope line through the wellbore storage regime (optional - mark the regime). Cs = 0.02 bbl/psi.
- Zero slope line through the vertical radial flow regime (enter the design open well length of
1000 ft at the prompt). kbar 1 md. Fit the flow regime markers to compute the skin factor S. (S is the “true” or mechanical skin factor.)
- Half-slope line in the ‘Linear flow through layer’ portion. Model Results display Lw = 960-990 ft.
- Zero slope in the (almost!) late radial flow regime. Model results display k = 1 - 1.1 md. PanSystem can now calculate kz = 0.88 - 1 md from kbar and k. Spr = –6.
Note the large negative pseudo-radial skin factor Spr, typical of a horizontal well. Note also the long time required for the reservoir to approach the late radial flow regime in the test.
Figure 4 - Log-log plot of the draw-down
Radial Flow Plot (Figure 5): Fitting lines through the radial flow portions give: Kbar 1 md., S 0,
K 1.1 md, Spr –6, Kz 0.9 md. Marking the radial flow regimes while on the log-log plot makes the radial flow plot line-fitting a lot easier and less prone to error.
You can move any line by selecting it (click the right mouse button, or press the Ctrl key and click on the line) and dragging a central or end grab-handle (small black square).
Figure 5 - Radial Flow plot
Linear Flow Plot (Figure 6): fitting a line through the linear flow portion gives: Lw 985 ft,
Sconv 3.9. Again, marking the linear (or quasi-linear) flow regime while on the log-log plot makes the line-fitting easier.
Figure 6 - Linear Flow Plot Where:
Kbar, is the average vertical radial permeability ( kzkk . )
Lw is the effective well length (ie: the producing interval) S is the mechanical skin factor
Spr is the pseudo-radial skin factor (or effective, or total skin factor) Sconv is the convergence skin – a component of the pseudo-radial skin factor.
Type curve plot: Select Log-log plot. Click the TC toolbar icon to perform Type Curve analysis. Select the M (Match) toolbar icon. In the Select Type Curve dialog box, select unknown well length for the Type Curve Method, with Default Type Curves clicked. Click OK. The Choose Zwd for these curves dialog box will appear as shown in Figure 7.
Figure 7 - Choosing Zwd
Select 0.5 as Zwd since the derivative does not show evidence that the well is excentered in the formation (no hemi-radial flow regime – step-like behaviour) and click OK. The plot will be presented with draw-down type curves for horizontal wells displayed.
Figure 8 - Horizontal Well Type Curve Match
The curves can be moved over the data by dragging them with the mouse until a match in found. When close to matching, you can use the arrow keys to move the curves if you prefer – coarse steps when pressed alone, fine steps when you hold down Ctrl and press the arrow key.
A better look into the type curve match can be obtained by zooming the data together with the type curves.
Once finished, you can display the final type curve by clicking M again
Once the type curves are matched, select M again to terminate matching mode. The nearest matching curve (counting bottom up) is displayed along with the corresponding value (curve #8, curve value = 12.00). Change the number displayed if you disagree with it. Select OK. The model parameters are computed from the match: Kz = 1.2 md, K = 0.9 md, Lw = 1045 ft., Zwd = 0.5.
Select the right arrow icon in the type curve matching toolbar to move to the next stage of type curve matching. Match the type curve that best fits the wellbore storage period (curve # 4, Cde
2S =
10). No vertical movement is permitted, since the vertical radial flow position of the derivative has already been fixed in the preceding stage. The model parameters are then computed from the
time and curve match: Cs 0.016 bbls/psi, S 0.2.
The screen should now be as shown in Figure 9.
Figure 9 - Wellbore Storage and Skin Type Curve Match Do not forget to confirm the results (Cnf icon) if you want to store them as the latest model parameters. Fine-tuning of the match can be performed in the Simulate menu using the option Quick Match, or using the Auto Match option (non- linear regression) after selecting some representative points in the derivative. Finally, check the quality of the analysis by inspecting the matching of the measured with the generated data on the various plots - log-log plot (Fig.10), radial flow plot (Fig.11), specialized (linear) flow plot, and test overview.
Figure 10 - Final Match: log-log plot
Figure 11 - Final Match: semi-log plot
2.2.3 Pseudo-radial flow
Once the pseudo-radial flow regime has been attained, the horizontal well behaves just like a vertical well with a skin factor equal to Spr in a reservoir of permeability k. The combined effects of all of the flow patterns particular to the horizontal geometry are lumped into Spr, which is usually strongly negative owing to the beneficial effect of the long drainhole Lw.
5.0)()4817.4ln(
AL
hSS
L
rS
w
conv
w
wpr
The term lnr
L
w
w
( . )4 4817 is a pseudo-radial areal flow convergence skin (into an equivalent vertical
well of radius Lw
4 4817. ). (Ref: Goode and Wilkinson (JPT Aug 91, and SPE 19341, (Morgantown, Oct
89) and supplement 23546).) The horizontal well can, therefore, be modeled as a vertical well, which is mathematically much simpler, once late radial flow has been attained, and onwards into semi-steady state. This is useful for IPR calculations. (The presence of boundaries which are close enough to be seen on the transient response before pseudo-radial flow is reached will complicate matters.)
Returning to Fig.8 (repeated below), take a look at the derivative shapes for the range of parameters covered.
Figure 12 - Horizontal Well Type Curves
Each curve represents a value of dimensionless well length k
k
h
LL zwWD , starting at 0.2 at the
bottom, and increasing to 200. Note that the classical horizontal welltest response, with the derivative starting in vertical radial flow, then rising through linear flow and ending in late radial flow, need not always be the case.
True linear flow (half-slope) will only develop if LWD is large enough. This implies a Lw >> h, and anisotropy will exert an influence too. LWD > 20 (curve #9) is a reasonable threshold.
Large LWD means a long test duration to reach pseudo-radial flow. A long drainhole in an isotropic formation will not reach pseudo-radial flow within a reasonable testing time, which means that horizontal permeability k will not be accessible from the test. However, with good quality data, it may be enough to have some curvature away from the linear flow portion (as in the example) to give a fairly good indication of which trend line we are on.
The “anti-classical” response, where the derivative goes down, or dips and barely rises, simply requires that LWD < 1 (curve #4 is LWD=1.2).
Another way of looking at this is to consider that the early vertical radial flow regime represents
the product zw kkL . , while the late radial flow regime represents kh. For the derivative to go
down into late radial flow, we require that zw kkLkh . , which, rearranging the terms,
means that 1 > LWD, ie: LWD < 1.
LWD=0.2
LWD=1.2
LWD=200
LWD=20
2.2.4 An Alternative Analysis
Figure 13 - An alternative interpretation – short well length, intersecting faults, but a rather high kz!
It is in fact possible to fit quite a range of parameter sets to this data, though the matches tend to be of poorer quality that the one just demonstrated. Reasonable matches can obtained with a short well length, high vertical permeability, and the addition of boundaries (something between 30° and 45° intersecting faults). Local knowledge (and common sense!) will be required to determine what might be acceptable in geological terms.
Example 1
Page 1
Edinburgh Petroleum Services PanSystem User Course
1
The Pressure Derivative
2
Pressure Drawdown Theory for an Infinite
Acting Reservoir with an Altered Zone
2
1ln 0.80908 2
2
141.2 1 0.000264ln 0.80908 2
2
D D
i wf
t w
p t S
qB ktp p S
kh c r
Hence plot pwf vs. ln t is a straight line
giving: pwf = m* lnt + pt=1
70.6qBm kh k
kh
1 2
1
2
0.000264ln 0.80908 2
1. . ln 7.43173
2
t i
t w
t i
t w
kp p m S
c r
p p ki e S
m c r
kh from slope of line
S from intercept
at t=1hr
Example 1
Page 2
Edinburgh Petroleum Services PanSystem User Course
3
Oilfield Units with Log10
2
1 2
1
2
162.6log log 3.2275 0.86859
162.6
log 3.2275 0.86859
1.1513 log 3.2275
i wf
t w
t hr i
t w
t hr i
t w
qB kp p t S
kh c r
qBm kh k
kh
kp p m S
c r
p p kS
m c r
kh from slope of line
S from intercept at t=1 hr
4
Pressure DerivativePressure Derivative
The pressure derivative in its simplest form - for a
drawdown with no previous history - is:
p = dpd(log t)
When rate history is involved (buildup test, any welltest
where there have been flowrate changes in the recent
past), the log ( t) is replaced by a more complex
logarithmic function based on superposition theory.
But the principles of interpretation are the same.
Example 1
Page 3
Edinburgh Petroleum Services PanSystem User Course
5
Pressure DerivativePressure Derivative
The pressure derivative:
• Magnifies changes in pressure trends
• Has slope values that identify flow regimes
• zero slope = radial flow
• ½-slope = linear flow
• and many others ….
• Has characteristic shapes that help identify the
reservoir and boundary models
• the most important ones should be memorised
6
Pressure DerivativePressure Derivative
For a constant rate drawdown in a radial homogeneous
reservoir, welltest theory says that:
p log( t)
P
log t
which means that dp = constantd(log t)
In radial flow,
pressure has constant slope
when plotted against log t
Derivative has constant valueP
Example 1
Page 4
Edinburgh Petroleum Services PanSystem User Course
7
Pressure DerivativePressure Derivative
A change of slope in the pressure is a change of
value in the derivative:
P
log t
For example, if a boundary (fault) is
detected, the pressure trend goes to
double slope
Derivative goes to new constant
value (two times old value)
P
8
Pressure DerivativePressure Derivative
The derivative is usually plotted on a log-log plot:
Log p
Log t
Radial flow
Boundary
??
Delta t
Example 1
Page 5
Edinburgh Petroleum Services PanSystem User Course
9
Pressure DerivativePressure Derivative
p = P0 - P
t = t -T0
(T0, P0)
Definition of Delta t and Delta P for a drawdown test
Data point at
(time = t, pressure = P)
Gauge clock time
10
•The way that delta P is defined for a
drawdown means that the pressure data
appears upside down on the log-log
plot:
Pressure DerivativePressure Derivative
Example 1
Page 6
Edinburgh Petroleum Services PanSystem User Course
11
Pressure DerivativePressure Derivative
p = P - P0
t = t -T0
(T0, P0)
Definition of Delta t and Delta P for a buildup test
Data point at
(time = t, pressure = P)
12
Pressure DerivativePressure Derivative
• Delta t (or t) is also referred to as Elapsed time - it
is the time that has elapsed from the start of the test
period (T0).
• Delta P (or P) is defined in such a way that it is
positive for a drawdown or a buildup.
• This means that the log-log plot for a drawdown
looks very much like the log-log plot for a buildup.
Example 1
Page 7
Edinburgh Petroleum Services PanSystem User Course
13
Pressure DerivativePressure Derivative
Drawdown
Buildup
p = P - P0
p = P0 - P
Equivalent time (hours) – Tp=100.0
EPS Derivative Diagnostic Library
p’t
∆t
∆te
Logarithmic derivative Elapsed time in a drawdown
Elapsed (shut-in) time in a buildup
Agarwal equivalent drawdown time
for a buildupETR Early time regionMTR Middle time regionLTR Late time region0s Derivative plateau1/2s Half slope1/4s Quarter slope1s Unit slope-1/2s Negative half slope-1s Negative unit slopeCRD Constant rate drawdownInfCon Infinite conductivityFinCon Finite conductivityW Channel widthL Distance to nearest boundaryLw horizontal well length
e-petroleumservices.comTelephone +44 (0)131 449 4536 Fax +44 (0)131 449 5123
Nomenclature
Vertical Fractured Well
Diagnostic Diagnostic
Diagnostic
DiagnosticDiagnostic
Diagnostic
Model Model
Model
ModelModel
Model
p p
p
pp
p
t t
t
tt
t
Fractured Well (InfCon) Fractured Well (FinCon)MTR
MTR
MTRMTR
ETR ETR
ETRETR
ETR
ETR
ETR
0s0s
0s
0s
0s0s
0s
1/2s
1/2s
1/4s
1/4s
1s
Horizontal Fracture
Horizontal FractureHorizontal Fracture
CRD
CRD
CRD
CRDCRD
CRD
CRDCRD
Thin Reservoir
MTR
MTR
F > 10CD
F < 10CD
Conductive Lens
"Geoskin"
B1
B2
B3
B4
B5
B6
Diagnostic DiagnosticModel Model
p p
t t
MTR
0s
ETR
1/2s
1/4s
Apparent Quarter Slope
CRD CRDB7 B8
with Storage and Skin
0s
0s1s
1/4s
MTR
ETRFractured Well (InfCon) Fractured Well (InfCon)
1/2s1/2s
1/2s
Fractured Well (FinCon)
Diagnostic Model
p
t CRD
Limited Height Fracture
hf
xf
MTRETR
HS
DP
IC
B9
Diagnostic Model
p
∆te BUFB10
Fractured Well (IC)
Agarwal Overcorrection
ETR
HS
US
Horizontal Wells
Diagnostic Diagnostic
Diagnostic
DiagnosticDiagnostic
Diagnostic
Model Model
Model
ModelModel
Model
p p
p
pp
p
t t
t
tt
t
H1
Lw
Lw
Lw
Lw
Horizontal Well
Horizontal Well
Horizontal Well
Horizontal Well
Horizontal WellHorizontal Well
Horizontal WellHorizontal Well
No Flow Upper and LowerBoundaries
No Flow Upper and LowerBoundaries
CRD
CRD CRD
CRD
MTR MTRMTRLTR LTRLTR
LTR
LTRLTR
0s 0s
0s0s
0s
0s
0s0s0s
0sP
1/2s
1/2s-1/2s
1/2s
0s1/2s
1/4s
H2
L > 10D
L > 10D
Acid Stimulation
PRFNatural Fracturesplus Face Skin
ETR
Offset Position
Tight Matrix
H3 H4
H5 H6
MTR
MTR
m2m
L < 0.2D
DrainHole
Diagnostic DiagnosticModel Model
p p
t tH7
Gas CapSupport (CPUB)
Horizontal Well Horizontal WellLTR LTR
0s 0s
MTR
MTR
m m
2m 2m
Strong BottomWater (CPLB)
H8CRD or BU-MDH
Diagnostic Model
p
t
Horizontal Well
Dual Porosity Strata
Low Perm. Layer0s
1/4s
ETR
H9 CRD
CRD or BU-MDH
0s
0s
0s
Diagnostic Model
p
tH10
Horizontal
Well
Matrix
Damage
ConductiveFault
1/2s-1/2s
1/4s
Wellbore Storage Overlay
Diagnostic Diagnostic
Diagnostic
DiagnosticDiagnostic
Diagnostic
Model Model
Model
ModelModel
Model
p p
p
pp
p
t t
t
tt
t
Ideal Wellbore StorageHomogeneous Reservoir
Nonideal Wellbore StorageHomogeneous Reservoir
Phase Redistribution- the "famous spike"
MTR
MTR
MTRETR
ETR
ETR
11/2 LogCycle
1s
1s
1s
0s
0s
0s
I1 I2
NWS
NWS
NWS
NWS
HR
HR
IWS HR
Near Single Fault
Far Single Fault
m
2m0s
1s
ETR
ETR
LTR
LTR
1s
MTR
0s0s
I3 I4
I5 I6
m2m
Dual Porosity Strata
Tight Zonem
m/20s
MTR
0s
ETR NWS
CRD
CRD
CRDCRDCRDCRD
CRDCRD
CRD
Diagnostic DiagnosticModel Model
p p
t t
IWS IWS
Fractured Well (InfCon) Fractured Well (FinCon)
No Skin No SkinETR MTR
0s
1/2s
1s
1/4s
1s
ETR
Small FCD
I7 I8
Diagnostic Model
p
t
NWS HR
I9
Phase Redistribution"Humping"
ETR MTR
0s
1s
m
0s
Diagnostic Model
p
tI10
ETR MTR
0s
1s0s
Dual Porosity
Semi-infinite Sealing Fault Systems Diagnostic Diagnostic
Diagnostic
DiagnosticDiagnostic
Diagnostic
Model Model
Model
ModelModel
Model
p
p
p
pp
p
t t
t
tt
t
L
Single Fault
CRD CRD
CRDCRD CRDCRD
CRDCRD
MTR
MTRMTR
MTR
MTR
MTR
MTR
LTR
LTR
LTR
LTR
LTRLTR
0s
1/2s
1/2s
1/2s
0s
0s
0s
0s0s
0s
0s0s
m
2m
L
Right Angle Faults
m
4m
Limited Extent (Baffle)
Lm
2m
Parallel Faults
Parallel Faults
W
WW
L
LL
U-Shaped Faults
Well Offsetm
2m
D1 D2
D3 D4
D5 D6
DiagnosticDiagnostic ModelModel
pp
∆t∆teBUF BUF
W WL L
MTR MTRLTR LTR
0s 0s1/2s1/2s
1s
Channel Reservoir Channel Reservoir
Agarwal Overcorrection Yeh Empirical Mod.
D7 D8
Single Fault
Diagnostic Model
p
t CRD
MTR LTR
D10
L
o120 Intersecting Faults
m
3m
o120
Diagnostic Model
p
t CRDD9
o45
L
o45 Intersecting Faults
m
8m MTR
LTR
1/2s
0s
0s0s
0s
Diagnostic Model
p
t CRD
LTR Open-ended U ShapeMTR
m2m
D11
0s
1/2s
0s
Diagnostic Model
p
t CRD
DP
LTRMTR
m2m
D12
Major and Minor Fault
0s
0s
1/2s
Double Porosity and Dual Permeability Systems
Diagnostic Diagnostic
Diagnostic
DiagnosticDiagnostic
Diagnostic
Model Model
Model
ModelModel
Model
p
p
p
p
p
p
t t
t
tt
t
Diagnostic Model
p
t CRD CRD
CRD
CRDCRD
CRD
CRD
MTR
MTR
MTR
MTR
ETR
ETR
ETRETR
ETR
LTR
ETR
0s
0s
0s
1s
0s
0s
0s
0s
0s
0s0s0s
0s0s
0s
1/2s
1s
Inf. Conductive Inner
Finite Wellbore Radius
Dual-porosity (transient)
Dual-Porosity (sss)
Interporosity Skin
No Interporosity Skin
m
m
m/2
m/2
Dual Porosity Strata
Tight Zone
High Perm. Zone
Reservoir Storage
High Perm Closed Layer
Infinite Low Perm. Layer
MTR
MTR
Dual Permeability
Semipermeable Barrier
C1
C2
C3
C4
C5
C6
Partially Communicating Faults and Linear Composite Systems Diagnostic Diagnostic
Diagnostic
DiagnosticDiagnostic
Diagnostic
Model Model
Model
ModelModel
Model
p
p
p
pp
p
t t
t
tt
t
Partially CommunicatingFault
Inf.-Acting
CRD
CRD CRDCRD
BUF
CRDCRD
CRD or BUD
LTR LTR
LTRLTRLTR
LTR LTRLTR
MTR MTR
MTR
MTR MTR
m
2m
0s
0s
0s 0s0s 0s
1s
1s 1s
0s 0s
0s0s
0s
G1 G2
LinearComposite
Linear Compositeplus Barrier
LinearComposite
G4G3
G5 G6
Two Cell Compartmentalised
Two Cell Compartmentalised
Closed Reservoir Compartments
Diagnostic Diagnostic
Diagnostic
DiagnosticDiagnostic
Diagnostic
Model Model
Model
ModelModel
Model
p p
p
pp
p
t t
t
tt
t
Closed Square Closed Square
CRD or BUD
CRD or BUD
CRD or BUD
BUF
BUF
BUFBUF
MTR
MTR MTR
MTRMTRLTR
LTR
LTR LTR
LTRLTR
LTR
0s
0s 0s
0s1s
1s
1s
1/2s
1/2s 1/2s
Rectangular Reservoir Rectangular Reservoir
Rectangular Reservoir Rectangular ReservoirRectangular Reservoir
1/2s
Offset Well Offset WellOffset Well
MTR
MTR
E1 E2
E3 E4
E5 E6
0s 0s
Constant Pressure Boundaries
Diagnostic Diagnostic
Diagnostic
DiagnosticDiagnostic
Diagnostic
Model Model
Model
ModelModel
Model
p p
p
pp
p
t t
t
tt
t
DistantGas Cap
0s
0s
0s-1s
-1s
-1s
MTR
MTR
MTRLTR
LTR
LTR
DistantStrong Aquifer
CRD or BU-MDH
CRD or BU-MDH
CRD or BU-MDH
CRD or BU-MDHCRD or BU-MDH
CRD or BU-MDH
CRD or BU-MDH
Gas CapSupport (CPUB)
LTR LTR
LTR
ETR ETR
0s 0s
Strong BottomWater (CPLB)
NonintersectingFracture
1/4s
Channel Reservoirwith Edge Water
CPB
MTR
1/2s
0s
F1 F2
F3 F4
F5 F6
Limited Entry and Radial Composite SystemsDiagnostic Model
p
t CRD
0s
MTR Homogeneous Reservoir
Infinite-Acting
A1
Diagnostic Model
p
t CRDCRD
MTRETR
0s
0s
Radial Composite
Tight Inner
A4
Diagnostic Model
p
t CRD
MTRETR
0s
Limited Entry
A2
Diagnostic Model
p
t CRD
MTRETR
0s
0s
Radial Composite
Conductive Inner
A5
Diagnostic Model
p
t CRD
MTRETR
0s
0s
Shale Lens
A6
Diagnostic Model
p
t CRD
MTRETR
0s
Extreme Limited Entry
A3
-1/2s
Diagnostic Model
p
t CRDA8
Well Offset in a ChannelMTR ETR
1/2s0s
Diagnostic Model
p
t
Top
Bottom
Pinch-Out
h
CRD
MTR LTR
m
A7
0s
-1/2s