AW Log Interpretation Charts

8/11/2019 AW Log Interpretation Charts

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...when experience matters

Table of Contents

I

Log Interpretation Charts

1. General

Borehole and Formation Parameters GEN-1Estimation of Formation Temperature with Depth GEN-2

Estimation of Formation Temperature with Depth Imperial GEN-4

Estimation of Formation Temperature with Depth Metric GEN-5

Equivalent NaCl Concentration of Salts GEN-6

Resistivity Salinity Temperature Conversions of NaCLl Solutions GEN-8

Resistivity of NaCl Solutions at 75 F GEN-11

Estimation of Rmf

and Rmc

from Rm

GEN-12

Formation Resistivity Factor versus Porosity GEN-15

2. Spontaneous Potential

SP Bed Thickness Correction SP-1

Rwe

Estimate from Static SP SP-3

Rwe

Estimate from Static SP - Imperical SP-5

Rwe

Estimate from Static SP - Metric SP-6

Estimation of Rw

from Rwe

SP-7

3. Induction Array

Induction Array Tool - Invasion Correction Charts IAT-1

Rt= 1 R

xo> R

tIA20/IA90 vs IA30/IA90 IAT-3

Rt= 10 R

xo> R


Rt= 1 IA20/IA90 vs IA30/IA90 IAT-5

Rt= 1 R

xo> R


Rt= 1 R

xo< R



Rt= 10 R

xo> R


Rt= 10 R

xo< R



Rt= 100 R

xo> R


Rt= 100 R

xo< R



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Table of Contents

II

4. Dual Laterolog

Dual Laterlog Borehole Corrections DLL-1

LLD Borehole Corrections Centralized DLL-2

LLD Borehole Corrections Eccentralized at 1.5 inch Standoff DLL-3

LLS Borehole Corrections Centralized DLL-4

LLS Borehole Corrections Eccentralized at 1.5 inch Standoff DLL-5

IAT versus DLL Selection DLL-6

5. Micro-Spherically Focused Log

Micro-Spherically Focused Log Mudcake Thickness Corrections MSFL-1

Mudcake Thickness Corrections MSFL-2

6. Spectral Gamma Ray

Spectral Gamma Ray Borehole Corrections GR-1

SGR Potassium (K) Borehole Corrections - Eccentralized GR-2

SGR Uranium (U) Borehole Corrections - Eccentralized GR-3

SGR Thorium (Th) Borehole Corrections - Eccentralized GR-4

SGR Potassium (K) Borehole Corrections - Centralized GR-5

SGR Uranium (U) Borehole Corrections - Centralized GR-6

SGR Thorium (Th) Borehole Corrections - Centralized GR-7

7. Compensated Neutron Log

Compensated Neutron Log (CNL) CNL-1

Open Hole Borehole Diameter CNL-5Open Hole Temperature CNL-6

Open Hole Standoff CNL-7

Open Hole Borehole Water Relative Density Eccentralized CNL-9

Open Hole Borehole Water Relative Density Centralized CNL-11

Open Hole Borehole Fluid Salinity Eccentralized CNL-13

Open Hole Borehole Fluid Salinity Centralized CNL-15

Open Hole Borehole Mud Density Corrections Eccentralized CNL-17

Open Hole Borehole Barite Mud Density Eccentralized CNL-19

Open Hole Mud Cake Thickness Eccentralized CNL-21

Open Hole Lithology CNL-23

Open Hole Formation Fluid Salinity CNL-24


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5/125


General

GEN-1

Borehole and Formation Parameters

Flushed

Zone

Uninvaded

Zone

Transition

Zon

e

(Annulus)

Mudcake

Mud

AdjacentBed

hmc

dh

di

dj

h

Rm

Rmc

Rxo Ri Rt

Rs

RwRmf

SwSxo

h bed thickness

hmc mudcake thickness

dh borehole diameter

di diameter of flushed zone

dj diameter of transition zone

Rm mud resistivity

Rmc mudcake resistivity

Rmf mud filtrate resistivity

Rxo flushed zone resistivity

Rt true resistivity

Rs adjacent bed resistivity

Rw formation water resistivity

Sxo flushed zone water saturation

Sw water saturation


6/125


General

GEN-2

Estimation of Formation Temperature with Depth

Purpose

This chart may be used to estimate the temperature gradient for a well by entering the depth and a known

temperature at that depth. The chart may also be used to determine a temperature at a given depth if atemperature at another depth is known and the geothermal gradient is assumed.

Procedure

To estimate the geothermal gradient for a well, enter the chart at a known depth on the vertical axis and then

project horizontally until intersecting the known temperature from the horizontal axis. The temperature on

the horizontal axis should correspond to the row with the Annual Mean Surface Temperature for the area in

which the well is located. The intersection of the vertical and horizontal lines can be interpolated to a

geothermal gradient if it falls between the printed temperature gradient lines.

To determine the temperature at any depth from another depth with a known temperature enter the chart on

the vertical axis point of the known depth and project horizontally until it intersects with the knowntemperature from the horizontal axis. From the intersecting point follow the gradient line until it intersects

the desired depth projection on the vertical axis. Project the intersected point down to the horizontal axis and

read the temperature from the appropriate row with the Annual Mean Surface Temperature.

Example

Given

TD of 14000 feet

Bottom hole temperature of 250 F

Mean annual surface temperature of 60 F

FindDetermine the temperature gradient for the well and the temperature at 9000 feet.

Answer

From the 14000 ft depth point on the vertical axis project horizontally across the chart. Since the mean annual

surface temperature is 60 F use the third temperature row at the bottom of the chart. From the 250 F point

project vertically into the chart until the two lines intersect. From this intersection point draw a line from to

the upper left corner of the chart. This geothermal gradient line can be interpolated between the 1.2 F/100 ft

and 1.4 F/100 ft gradient lines at approximately 1.37 F/100 ft.

From the intersection of the 1.37 F/100 ft gradient line and the 9000 ft depth line project down and read the

temperature from the third line at the bottom of the chart (corresponding to the 60 F mean surface

temperature). The temperature at 9000 ft should be approximately 183 F.


7/125


General

GEN-3

Equations

G = geothermal gradient

TAMST= annual mean surface temperature

Td1= Temperature at depth 1

Td2= Temperature at depth 2d = depth

d1= depth 1

d2= depth 2

Geothermal Gradient calculation

G = 100T Td d

Temperature at depth calculation

T= T+ 0.01(G d)

Conversion factors

1 F/100 ft = 1.823 C/100 m

1 C/100 m = 0.5486 F/100 ft


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11/125


General

GEN-7

10 20 50 100 200 500 1000 2000 5000 10000 20000 50000 100000 300000

-0.5

0.0

0.5

1.0

1.5

2.0

Multiplier

Total Concentration (ppm)

Equivalent NaCl Concentrations of Salts

Na and Cl

K

HCO3

SO4

Mg

Ca

CO3


12/125


General

GEN-8

Resistivity Salinity Temperature Conversions of NaCl Solutions

Purpose

This chart may be used to estimate the resistivity value of an equivalent NaCl solution at a given temperature

or to determine the resistivity at one temperature given the resistivity at another temperature.

Procedure

To estimate the resistivity of the solution, enter the chart on the horizontal axis at the given temperature.

Project this line vertically until intersection with the given equivalent concentration line. Project this

intersection point horizontally to determine the resistivity.

For a solution with a known resistivity and temperature the resistivity at another temperature can be found.

Enter the chart on the horizontal axis at the first temperature and on the vertical axis at the corresponding

resistivity. Project both lines to find the intersection point. If the intersection point is between the ppm

concentration lines interpolate between them to find a corresponding equivalent NaCl ppm concentration.

Follow this line to the vertical projection of the temperature for the unknown resistivity. At the intersection ofthe ppm concentration and the temperature project horizontally to read the resistivity at that temperature.

Example

Given

Water with an equivalent NaCl concentration of 30,000 ppm

Temperature of 150 F

Find

Determine the resistivity of the solution.

AnswerFrom the 150 F temperature point on the horizontal axis project vertically into the chart until the line

intersects the 30 000 ppm line. At the intersection point project horizontally to read the resistivity from the

vertical axis scale of 0.105 ohmm.

Given

Resistivity of a solution is 0.4 ohmm

Temperature is 180 F

Find

Determine the resistivity of the solution at 70 F.

Answer

From the 180 F temperature point on the horizontal axis project vertically into the chart until the line

intersects the 0.4 ohmm projected resistivity line. Follow the ppm concentration line to the projection of the

70 F line. Interpolate the concentration line if necessary. Project the intersection point horizontally to read

the new temperature of 0.99 at 70 F.


13/125


General

GEN-9

Equations

R1= Resistivity of sample 1

R1= Resistivity of sample 2

T1= Temperature of sample 1

T2= Temperature of sample 2

Calculation with temperature in degrees Fahrenheit

R= R T+ 6.77T+ 6.77

Calculation with temperature in degrees Celcius

R= R T+ 21.5T+ 21.5


14/125


General

GEN-10

0.006

0.008

0.01

0.02

0.03

0.04

0.06

0.08

0.1

0.2

0.3

0.4

0.6

0.8

1

2

3

4

6

8

10

30 40 50 60 70 80 90 100 150 200 250 300 350 400

0 2 4 6 8 10 15 20 30 40 50 60 70 80 90 100 150 200

0.006

0.008

0.01

0.02

0.03

0.04

0.06

0.08

0.1

0.2

0.3

0.4

0.6

0.8

1

2

3

4

6

8

10

ResistivityofSolution(ohmm

)

Temperature (F)

Resistivity - Salinity - Temperature

Conversions of NaCl Solutions

Temperature (C)


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General

GEN-11

0.01

0.1

1

10

100

100 1000 10000 100000 1000000

R

esistivityat75F(ohmm)

NaCl Salinity (ppm)

Resistivity of NaCl Solutions at 75 F


16/125


General

GEN-12

Estimation of Rmfand Rmcfrom Rm

PurposeThis chart may be used to estimate the mud filtrate and mudcake resistivities given the mud resistivity and

drilling mud density.

ProcedureTo estimate the mud filtrate resistivity (Rmf) or mudcake resistivity (Rmc) enter the chart on the horizontal axis

at the appropriate Rm value. Project this line vertically until it intersects the drilling fluid density curve for

either Rmf or Rmc. Project the intersection point horizontally to determine the resistivity of either the mud

filtrate or mudcake.

ExampleGiven

Rmf= 3.0 ohmm

Drilling fluid density = 12 lb/gal

Find

Estimate the resistivity of the mud filtrate and mud cake.

Answer

From the 3.0 ohmm point on the horizontal axis project vertically into the chart until the line intersects the

solid 12 lb/gal curve and the dashed 12 lb/gal curve. At the intersection point from each of these curves

project horizontally to read the resistivity for each of the mud filtrate, 1.1 ohmm and mudcake 4.4 ohmm.

Equations

Rm= mud resistivityRmf= mud filtrate resistivity

Rmc= mudcake resistivity

km= Coefficient of the mud

Mud Density Coefficient of the mud

lb/gal kg/m3 km

10 1198 0.847

11 1318 0.708

12 1438 0.584

13 1558 0.488

14 1678 0.41216 1917 0.380

18 2157 0.350


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General

GEN-13

Rmfand Rmccan be calculated using the following equations and the values from the table above.

R= k R.

R= 0.69 R RR.


18/125


General

GEN-14

0.01

0.02

0.03

0.04

0.05

0.06

0.08

0.1

0.2

0.3

0.4

0.5

0.6

0.8

1

2

3

4

5

6

8

10

0.01 0.02 0.04 0.06 0.1 0.2 0.3 0.4 0.6 0.8 1 2 3 4 6 8 10

ResistivityofMudFiltrate,

Rmf

(ohmm

)

Resistivity of Mud, Rm (ohmm)

Estimation of Rmfand Rmc from Rm

ResistivityofMudcake,

Rmc

(ohmm

)

Mud Density

lb/gal kg/m3

10 1198

11 1318

12 1438

13 155814 1678

16 1917

18 2157

Mud Density

lb/gal kg/m3

10 119811 1318

12 1438

13 1558

14 1678

16 1917

18 2157

Rmc

Rmf


19/125


General

GEN-15

Formation Resistivity Factor versus Porosity

Purpose

This chart may be used to determine the formation resistivity factor for a given porosity.

Procedure

To estimate the formation resistivity factor (F) enter the chart on the vertical axis at the appropriate porosity

value. Project this line horizontally until it intersects the desired cementation exponent curve (m) for the rock

type. Project the intersection point vertically to determine the formation resistivity factor (F).

Example

Given

a = 1.0

m = 1.8

= 10 %

Find

Estimate the formation resistivity factor (F).

Answer

From the 10 % point on the vertical axis project horizontally into the chart until the line intersects the m=1.8

curve. At the intersection point project vertically to read the formation resistivity factor of 62 from the

horizontal axis.

Equations

F = formation resistivity factor

a = tortuosity factor

m = cementation exponent = porosity

General equation

F =a

For sandstones

F =0.62

. or F =

0.81

For carbonates

F =1.0


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21/125


Spontaneous Potential

SP-1

SP Bed Thickness Correction

Purpose

This chart may be used to correct the spontaneous potential (SP) log for the effects of bed thickness.

Procedure

To estimate the SP correction factor first determine the ratio between the true formation resistivity and the

mud resistivity at the formation temperature. Enter the chart on the vertical axis at the estimated bed

thickness. Units of feet are on the left side of the chart and meters are on the right side of the chart. Project

the line horizontally until it intersects the curve closest to the R t/Rmvalue. Values between the curves can be

interpolated. From the intersection point project vertically down to read the SP correction factor. Multiply

the SP reading from the log by this correction factor to obtain a corrected SP log for bed thickness. Thicker

beds should have less correction effects.

Example

Given

SPLOG= -80 mV

h = 7 feet

Rt= 24 ohmm

Rm= 1.2 ohmm

Find

Estimate the SP corrected for bed thickness.

Answer

Determine the Rt/Rmratio.

R

R=

24 ohm m

1.2 ohm m= 20

Enter the chart on the left vertical axis at 7 feet and project horizontally until the line intersects the Rt/Rm=20

curve. Project this intersection point vertically to the lower axis to obtain an SP correction factor of 1.34.

Multiply the SP reading from the log by the correction factor to obtain a corrected SP reading of -107.2 mV.

SPCORR= SPLOGSPCorreciton Factor

SPCORR= -80 mV 1.34 = -107.2 mV


22/125



SP-2

4

5

6

7

8

9

10

11

12

13

14

15

20

25

30

1.0

1.5

2.0

2.5

3.0

4.0

5.0

6.0

7.0

8.0

9.0

BedThickness(feet)

BedThickness(meters)

Rt

Rm

5 10 60 15010020 40 80 200


23/125



SP-3

RweEstimate from Static SP

Purpose

This chart may be used to determine the equivalent water resistivity from the static spontaneous potential

(SSP).

Procedure

To estimate Rwe first enter the chart on the lower axis with the SSP in millivolts. Project this line vertically until

intersecting the appropriate temperature line. Project the intersection of the SSP and temperature line

horizontally to determine the Rmfe/Rweratio. Rwecan be determined by dividing the Rmfecalculated from the

log by the Rmfe/Rweratio.

Example

Given

Rmf= 1.4 ohmm @ 75 F

SSP = -110 mV

Temperature = 150 F

Find

Estimate the Rwe.

Answer

Determine the equivalent mud resisitivity. Since Rmf> 0.1 at 75 F we can use chart GEN 4b to determine the

Rmfat the formation temperature of 150 F. From the chart the Rmfat 150 F is 0.7 ohmm.

Rmfe= 0.85Rmf= 0.85 x 0.7 = 0.595 ohmm

Enter the chart on the horizontal axis at SSP = -110 mV. Project this line vertically until it intersects the 150 F

temperature line. Project this intersection point horizontally to the left to read the Rmfe/Rweratio of 23.

R

R= 23

Input the value of 0.595 ohmm for Rmfeinto the equation and solve for Rweto get 0.0259 ohmm.

R=0.595

23= 0.0259 ohm m


24/125



SP-4

Equations

If Rmfat 75 F is > 0.1 ohmm then correct Rmfto formation temperature using chart GEN 4band the

equation: Rmfe= 0.85Rmf

If Rmfat 75 F is < 0.1 ohmm then use chart SP 3to find Rmfeat the formation temperature.

SSP = static spontaneous potential

Td= Temperature at formation depth

Rmfe= equivalent mud filtrate resistivity

Rwe= equivalent water resistivity

Static SP calculation with temperature in degrees Fahrenheit

707 460 + T537 RR

Static SP calculation with temperature in degrees Celcius

707 273 + T298 RR


25/125


26/125



SP-6

0.1

0.2

0.5

1

2

5

10

20

50

100

-200.0-150.0-100.0-50.00.050.0100.0

RmfeRwe

Static SP (mV)

Rwe Estimate from Static SP

250

225

200

175

25 15012510075500CFormation Temperature


27/125


28/125



SP-8

0.001 0.002 0.005 0.01 0.02 0.05 0.1 0.2 0.5 1 2 5 10

0.001

0.002

0.005

0.01

0.02

0.05

0.1

0.2

0.5

1

2

5

10

R

esistivityofWater,Rw(ohmm)

Resistivity of Water Equivalent, R (ohmm)

Estimation of Rw from Rwe

500 F

300 F250 F

150 F

400 F

200 F

100 F

75 F

75F

300F

250F

200F

150F

100F

500F

400F


29/125


Induction Array

IAT-1

Induction Array Tool - Invasion Correction Charts

Purpose

These charts may be used to determine the true resistivity, flushed zone resistivity and the diameter of

invasion from the IAT logs. Separate charts are presented for different formation resistivity values and using

different shallow array curves from the IAT tool. The existing charts are all for thick beds with a step profile

invasion.

Procedure

Enter the chart with the ratio of the curves IA30/IA90 on the horizontal axis and the ratio of the IA20/IA90

curves on the vertical axis. The intersection of the two projections determines the diameter of invasion on the

red dashed curves, Rxo/Rton the blue curves and Rt/IA90 on the black curves. If the intersection does not lie

on existing curves then the value may be obtained by interpolating between the two bounding curve values.

Example

Given

IA20 = 50 ohmm

IA30 = 31 ohmm

IA90 = 14 ohmm

Rxo= ohmm

Find

Determine Rt, Rxoand diameter of invasion (Di).

Answer

Calculate the required ratios for the chart:

IA20

IA90=

50 ohm m

14 ohm m= 3.6

IA30

IA90=

31 ohm m

14 ohm m= 2.2

Using the chart IAT 2, as the estimated Rt will be close to 10, enter the chart at 3.6 on the vertical IA20/IA90

axis and project horizontally into the chart. Enter the chart at 2.2 on the horizontal IA30/IA90 axis and project

vertically into the chart.

Using the intersection point, interpolate between the solid black lines to determine the ratio Rt/IA90 = 0.825.

Calculate Rtto be 11.6 ohmm.

R

IA90=

R

14 ohm m= 0.825 R= 11.6 ohm m

Using the intersection point again, interpolate between the solid blue lines to determine the ratio Rxo/Rt= 9.0.

Calculate Rxoto be 104.4 ohmm.


30/125


Induction Array

IAT-2

R

R=

R

11.6 ohm m= 9.0 R= 104.4 ohm m

Using the intersection point again, interpolate between the dashed red lines to determine the diameter of

invasion to be 83 inches.


31/125


Induction Array

IAT-3

1

2

3

4

5

6

7

8

1 1.5 2 2.5 3 3.5

IA20/IA90

IA30/IA90

Induction Array Tool - Invasion Corrections

Rt = 1 ohmm Rxo > Rt

Rxo/Rt

50

4

2

6

8

10

12

15

20

25

30

40

Di = 100"

20"

30"

40"

50"

60

"

70"

80"

90"

Rt/IA90 = 0.75

0.8

1.0

0.85

0.95

0.9

0.975


32/125


Induction Array

IAT-4

1

2

3

4

5

6

7

8

1 1.5 2 2.5 3 3.5

IA20/IA90

IA30/IA90

Induction Array Too - Invasion Corrections


2

4

15

25

20

12

30

8

10

40

Rxo/Rt

6

Di = 100"

40"

50"

70"

60"

20"

30"

80"

90"

Rt/IA90 = 0.75

0.8

0.85

0.9

0.95

0.975

1.0


33/125


Induction Array

IAT-5

0.1

1

10

100

0 0.5 1 1.5 2 2.5 3 3.5

IA10/IA90

IA30/IA90


Rt= 1 ohmm

Rxo/RtDi= 100"

Rt/IA90 = 2

50

0.25

2

0.5

1

4

6

8

10

12

15

20

30

90"

30"

40"

20"

50"

60"

70"

80"

20"

90"

50"

80"

70"

60"

40" 30"

100"

0.750.8

0.95

0.9

0.85

0.975

1

1.5

1.05

1.21.1


34/125


Induction Array

IAT-6

1

6

11

16

21

26

31

36

1 1.5 2 2.5 3 3.5

IA10/IA90

IA30/IA90



Rxo/RtDi = 100"

Rt/IA9

0 0.975

50

15

20

30

90"

30"

20"

40"

50"

60"

70"

80"

0.95

0.9

0.85

0.8

0.75


35/125


Induction Array

IAT-7

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

IA10/IA90

IA30/IA90


Rt = 1 ohmm Rxo < Rt

Rxo/Rt

Di = 100"

Rt/IA90 = 1.05

0.5

0.25

90"

20"70"

60"

40"30"50"

80"

1.2

1.5

1.1

2


36/125


Induction Array

IAT-8

0.01

0.1

1

10

100

0 0.5 1 1.5 2 2.5 3 3.5

IA10/IA90

IA30/IA90


Rt= 10 ohmm

Rxo/Rt

40

30

25

1

2

8

12

15

20

4

0.067

0.1

0.125

0.25

0.167

0.5

0.083

0.05

Di= 100"

100"90"

90"

70"

50"

40"

80"

30"

30"

20"

60"

20"

40"

50"

60"

70"80"

Rt/IA90 = 2

0.750.8

1

0.975

0.95

0.9

0.85

0.975

11.05

0.95

1.11.2

1.5


37/125


38/125


Induction Array

IAT-10

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

IA10/IA90

IA30/IA90



0.975 Rt/IA90 = 0.95

Di = 100"

Rxo/Rt

0.5

0.167

0.1

0.125

0.067

0.05

0.25

0.083

90"

70"

20"

80"

30"40"

50"

60"

1.2 11.05

2

1.5

1.1


39/125


Induction Array

IAT-11

0.01

0.1

1

10

0 0.5 1 1.5 2 2.5

IA10/IA90

IA30/IA90


Rt= 100 ohmm

Rxo/Rt

0.25

0.5

0.05

0.067

0.083

0.1

0.125

0.167

1

4

2

100"

Rt/IA90 = 2

90"

20"

30"

40"

50" 60" 70" 80"

20"

70"

30"

60"

40"

50"

80"

Di= 100"

90"

1.5

0.975

1

1.1

1.05

1.2

0.975

0.95

0.95

0.9 0.85


40/125


Induction Array

IAT-12

1

1.5

2

2.5

3

3.5

4

1 1.2 1.4 1.6 1.8 2 2.2

IA10/IA90

IA30/IA90

Induction Array Tool - Invastion Corrections


Rxo/Rt4

2

Di = 100"

90"

20"

30"

40"

50"

60"70"

80"

Rt/IA90

1

0.975

0.85

0.9

0.95


41/125


Induction Array

IAT-13

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

IA10/IA90

IA30/IA90



Rxo/Rt

0.25

0.067

0.167

0.125

0.1

0.083

0.05

0.5

Di = 100"

Rt/IA90 = 0.95

90"

80"

20"

30"

60"

40"

50"

70"

1.51.2 1.051.1 1 0.975

2


42/125


Dual Laterolog

DLL-1

Dual Laterolog Borehole Corrections

Purpose

This chart may be used to correct the dual laterolog deep and shallow curves for the effect of borehole size.

Procedure

Choose the appropriate chart for the deep (LLD) or shallow (LLS) curve and whether the tool was centralized

or decentralized with standoff. To estimate the correction for borehole size, calculate the ratio of the

appropriate curve resistivity to the mud resistivity and enter the chart on the horizontal axis at this value.

Project vertically until the projection intersects the appropriate borehole diameter line. Interpolate between

the borehole size lines if necessary. At the intersection point project horizontally to read the ratio of the true

resistivity to the dual laterolog resistivity. Multiply the value of this ratio by the dual laterolog resistivity to

determine the borehole size corrected resistivity.

Example

Given

LLD = 24 ohmm

LLS = 22 ohmm

Rm= 0.12 ohmm

dh= 10.0 inches

DLL tool was centralized

Find

Estimate the deep resistivity corrected for borehole size.

Answer

Determine the RLLDto Rmratio from the log parameters.

R

R

=24

0.12= 200

Using the chart for a centralized deep dual laterolog tool (DLL1) enter the horizontal axis at 200 and project

vertically into the chart to the 10 inch borehole size line. Project the intersection point horizontally to the

axis to read 1.037.

Multiply the LLD reading from the log by this correction factor to obtain the borehole corrected reading of

24 ohm m 1.037 = 24.89 ohm m


43/125


Dual Laterolog

DLL-2

0.8

0.9

1

1.1

1.2

1.3

1.4

1.5

1 10 100 1000 10000 100000

Rt

/RLLD

RLLD/Rm

Dual Laterolog Borehole CorrectionsLLD - Centralized

6" Borehole

8" Borehole

10" Borehole

12" Borehole

14" Borehole

16" Borehole


44/125


45/125


Dual Laterolog

DLL-4

0.8

0.9

1

1.1

1.2

1.3

1.4

1.5

1 10 100 1000 10000 100000

Rt

/RLLd

RLLD/Rm

Dual Laterolog Borehole CorrectionsLLS - Centralized

8" Borehole

6" Borehole

10" Borehole

12" Borehole

14" Borehole

16" Borehole


46/125


Dual Laterolog

DLL-5

0.8

0.9

1

1.1

1.2

1.3

1.4

1.5

1 10 100 1000 10000 100000

Rt

/RLLd

RLLD/Rm

Dual Laterolog Borehole CorrectionsLLS Eccentered at 1.5" Standoff

6" Borehole

10" Borehole

12" Borehole

14" Borehole

16" Borehole

8" Borehole


47/125


Dual Laterolog

DLL-6

0.2

2

20

200

2000

0.01 0.1 1 10 100 1000 10000

Rt

(ohmm)

Rt/Rm

IAT verses DLL Selection

IAT 4-ft limit

IAT 2-ft limit

IAT

and/or

DLL

DLL

DLL limit

IAT


48/125


49/125


Micro-Spherical Focused Log

MSFL-2

0.1

1

10

100

1 10 100 1000

Rmsfl_

corr/

Rmsfl

Rmsfl/Rmc

MSFL Mudcake Thickness Correction

1/2"

3/8"

1/4"

5/8"

7/16"

1/8"

1/16"


50/125


Spectral Gamma Ray

GR-1

Spectral Gamma Ray Borehole Corrections

Purpose

These charts may be used to correct the Spectral Gamma Ray (SGR) outputs for the effect of mud weight and

borehole diameter on the measurements.

Procedure

Use the gamma ray component (K, U, Th) chart for either a decentered or centralized tool. Using the borehole

size on the horizontal axis, project vertically until the projection intersects the appropriate line for the mud

weight in the borehole. Interpolate between the mud weight lines as necessary. At the intersection point,

project horizontally to read the ratio of the corrected gamma ray component (K,U or Th) to the gamma ray

component reading from the log. Multiply the value of this ratio by the SGR component reading from the log

to determine the corrected component reading.

Example

Given

dh= 12 inches

Mud Weight = 10 lb/gal

Klog= 3 %

Eccentered Tool

Find

Estimate the corrected Potassium (K) reading corrected for mudweight and borehole size.

Answer

Use chart GR 1for an eccentered Potassium component from the SGR.

Enter the horizontal axis at 8.75 inches and project vertically into the chart to the 10 lb/gal mud weight line.

Project the intersection point horizontally to the

axis to read 1.235.

Multiply the potassium (K) reading from the log by this correction factor to obtain the corrected potassium

reading of 3.7 %.

K= 3 % 1.235 = 3.705 %


51/125


Spectral Gamma Ray

GR-2

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

3 4 5 6 7 8 9 10 11 12 13 14 15 16

Kcorr

/Klog

Borehole Diameter (inch)

Spectral Gamma Ray Borehole Correction for PotassiumEccentered Tool


52/125


Spectral Gamma Ray

GR-3

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

3 4 5 6 7 8 9 10 11 12 13 14 15 16

Ucorr

/Ulog


Spectral Gamma Ray Borehole Correction for Uranium

Eccentered Tool


53/125


Spectral Gamma Ray

GR-4

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

3 4 5 6 7 8 9 10 11 12 13 14 15 16

Th

corr

/Thlog


Spectral Gamma Ray Borehole Correction for Thorium

Eccentered Tool


54/125


Spectral Gamma Ray

GR-5

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

3 4 5 6 7 8 9 10 11 12 13 14 15 16

Kcorr

/Klog


Spectral Gamma Ray Borehole Correction for Potassium

Centered Tool


55/125


Spectral Gamma Ray

GR-6

0.5

1.0

1.5

2.0

2.5

3.0

3.5

3 4 5 6 7 8 9 10 11 12 13 14 15 16

Ucorr

/Ulog


Spectral Gamma Ray Borehole Correction for Uranium

Centered Tool


56/125


Spectral Gamma Ray

GR-7

0.5

1.0

1.5

2.0

2.5

3.0

3.5

3 4 5 6 7 8 9 10 11 12 13 14 15 16

Th

corr

/Thlog


Spectral Gamma Ray Borehole Correction for Thorium

Centered Tool


57/125


Compensated Neutron Log

CNL-1

Compensated Neutron Log (CNL)

Purpose

The Compensated Neutron Log (CNL) response is affected by environmental parameters. These parameters

are related to the tool string configuration, the borehole environment and the formation. The CNL tool

records the raw short space and long space detector counts from which the ratio of these detector counts is

used to calculate the apparent neutron porosity of the formation. Environmental correction factors are then

applied to this uncorrected porosity to produce accurate corrected neutron porosity.

In the Warrior logging software the curve NPHI is the uncorrected neutron porosity. The curve NPHC is

neutron porosity that is corrected for borehole size only.

The Warrior software also produces fully corrected curves for each of the three common formation matrices.

The logging parameters/variables that are input into the Warrior software are the inputs to the corrections

that are applied while logging. These corrected curves are:

NPHL Neutron Porosity Limestone matrix

NPHS Neutron Porosity Sandstone matrix

NPHD Neutron Porosity Dolomite matrix

Using the correction charts the environmental corrections can be applied manually to the uncorrected

porosity. The corrections can also be backed out of the corrected CNL porosity value using the same

correction charts.

The correction charts are specific to the logging environment and the type of neutron source used for logging.

Charts are available for both Americium-241/Beryllium and Californium-252 neutron sources as well as for

Open Hole and Cased Hole wells.

Procedure

The neutron corrections are referenced to the standard conditions indicated by the solid red line on each

chart. The standard conditions for Open Hole are:

Formation Formation Well Temperature Hole Tool

Fluid Fluid Diameter Position

Eccentralized

Limestone Pure Water Pure Water 20 C 8.0" Source

to Wall


58/125


59/125



CNL-3

e. Borehole Water Relative Density

f. Borehole Fluid Salinity

g. Formation Fluid Salinity

4. Correct the porosity from step 3 for lithology depending on eccentralized or centralized tool.

Example

Given

Open hole well

Californium-252 neutron source

Uncorrected neutron porosity = 31.5%

8.5 inch borehole

100,000 ppm borehole salinity

100,000 ppm formation salinity

100 C borehole temperature

standoff between tool and borehole wallMud density of 1.17 g/cm

3

Mud cake thickness of 0.25 inches

Find

Determine the corrected neutron porosity in both limestone matrix and sandstone matrix from the

parameters given.

Answer

Using chart CNL 1 enter the vertical axis on the Borehole Diameter Correction chart at 8.5 inches. Project the

line horizontally until it intersects the 31.5 % porosity line. Interpolate between the blue curves on either side

of the intersection and follow the general trend back to the red baseline at 31% porosity.

Using the porosity obtained in the step above (31%), enter each of the following charts and record the change

in porosity. Sum the individual porosity changes.

a) Temperature Correction Chart (CNL 2) +2.2 %

b) Stand Off Correction Chart Eccentralized (CNL 3) -0.4 %

c) Borehole Water Relative Density Correction (CNL 5) 0 %

d) Borehole Fluid Salinity Correction Eccentralized (CNL 9) -0.2 %

e) Mud Density Correction (CNL 13) Eccentralized (CNL 13) +0.3 %

f) Mud Cake Thickness Correction Eccentralized (CNL 17) +0.2 %

Sum of Corrections = +2.1 %

Add the sum of the porosities to the Borehole diameter corrected porosity to obtain a porosity to enter into

the next charts.

31 % + 2.1 % = 33.1 %


60/125



CNL-4

Using the corrected porosity of 33.1 % enter the Lithology Correction chart on CNL 19. For the Limestone

matrix, follow the blue line straight down to obtain a porosity of 33.1 %. For the Sandstone matrix, follow the

yellow line to obtain a matrix corrected porosity of 38 %.

Using the lithology matrix corrected porosities enter the Formation Fluid Salinity correction chart for theappropriate matrix on page CNL 20.

The corrected neutron porosity on a limestone matrix would be 29.2 % and on a sandstone matrix it would be

33.7 %.


61/125



CNL-5

U-FLT CNL009 Californium 252Open Hole Borehole Diameter Correction

6

8

10

12

14

16

-5 0 5 10 15 20 25 30 35 40 45 50 55

BoreholeDiameter[inch]

Porosity [p.u.]

Borehole Diameter Correction


62/125



CNL-6

U-FLT CNL009 Californium 252Open Hole Temperature Correction

0

50

100

150

200

-5 0 5 10 15 20 25 30 35 40 45 50 55

ToolTemperature[C]

Porosity [p.u.]

Tool Temperature Correction


63/125



CNL-7

U-FLT CNL009 Californium 252Open Hole Standoff Corrections

0

0.5

1

1.5

-5 0 5 10 15 20 25 30 35 40 45 50 55

ToolStandoff[inch]

Porosity [p.u.]

6.0" Borehole Tool Standoff Correction

0

0.5

1

1.5

2

2.5

-5 0 5 10 15 20 25 30 35 40 45 50 55

To

olStandoff[inch]

Porosity [p.u.]


0

1

2

3

4

-5 0 5 10 15 20 25 30 35 40 45 50 55

ToolStandof

f[inch]

Porosity [p.u.]



64/125



CNL-8

U-FLT CNL009 Californium 252Open Hole Standoff Corrections

0

1

2

3

4

5

-5 0 5 10 15 20 25 30 35 40 45 50 55

ToolStandoff[inch]

Porosity [p.u.]


0

1

2

3

4

5

6

-5 0 5 10 15 20 25 30 35 40 45 50 55

ToolStandoff[inch]

Porosity [p.u.]


0

1

2

3

4

5

6

7

-5 0 5 10 15 20 25 30 35 40 45 50 55

ToolStandoff[inch]

Porosity [p.u.]



65/125



CNL-9

U-FLT CNL009 Californium 252Open Hole Borehole Water Relative Density Corrections Eccentralized Tool

0.92

0.94

0.96

0.98

1.00

1.02

-5 0 5 10 15 20 25 30 35 40 45 50 55BoreholeWaterRelativeDensity[g/cm]

Porosity [p.u.]

6.0" Borehole Water Relative Density Correction

0.92

0.94

0.96

0.98

1.00

1.02

-5 0 5 10 15 20 25 30 35 40 45 50 55BoreholeW

aterRelativeDensity[g/cm]

Porosity [p.u.]


0.92

0.94

0.96

0.98

1.00

1.02


Porosity [p.u.]



66/125



CNL-10

U-FLT CNL009 Californium 252Open Hole Borehole Water Relative Density Corrections Eccentralized Tool

0.92

0.94

0.96

0.98

1.00

1.02


Porosity [p.u.]


0.92

0.94

0.96

0.98

1.00

1.02

-5 0 5 10 15 20 25 30 35 40 45 50 55Borehole

WaterRelativeDensity[g/cm]

Porosity [p.u.]


0.92

0.94

0.96

0.98

1.00

1.02


Porosity [p.u.]



67/125



CNL-11

U-FLT CNL009 Californium 252Open Hole Borehole Water Relative Density Corrections Centralized Tool

0.92

0.94

0.96

0.98

1.00

1.02


Porosity [p.u.]


0.92

0.94

0.96

0.98

1.00

1.02

-5 0 5 10 15 20 25 30 35 40 45 50 55BoreholeW


Porosity [p.u.]


0.92

0.94

0.96

0.98

1.00

1.02

-5 0 5 10 15 20 25 30 35 40 45 50 55BoreholeWaterRelative

Density[g/cm]

Porosity [p.u.]



68/125



CNL-12

U-FLT CNL009 Californium 252Open Hole Borehole Water Relative Density Corrections Centralized Tool

0.92

0.94

0.96

0.98

1.00

1.02


Porosity [p.u.]


0.92

0.94

0.96

0.98

1.00

1.02


Porosity [p.u.]


0.92

0.94

0.96

0.98

1.00

1.02

-5 0 5 10 15 20 25 30 35 40 45 50 55BoreholeWaterRelativeD

ensity[g/cm]

Porosity [p.u.]



69/125



CNL-13

U-FLT CNL009 Californium 252Open Hole Borehole Fluid Salinity Corrections Eccentralized Tool

0

50

100

150

200

250

-5 0 5 10 15 20 25 30 35 40 45 50 55BoreholeFluidSalinity[kppm]

Porosity [p.u.]

6.0" Borehole Fluid Salinity Correction

0

50

100

150

200

250

-5 0 5 10 15 20 25 30 35 40 45 50 55Boreho

leFluidSalinity[kppm]

Porosity [p.u.]


0

50

100

150

200

250

-5 0 5 10 15 20 25 30 35 40 45 50 55BoreholeFluidSa

linity[kppm]

Porosity [p.u.]



70/125


71/125



CNL-15

U-FLT CNL009 Californium 252Open Hole Borehole Fluid Salinity Corrections Centralized Tool

0

50

100

150

200

250


Porosity [p.u.]


0

50

100

150

200

250


Porosity [p.u.]


0

50

100

150

200

250

-5 0 5 10 15 20 25 30 35 40 45 50 55BoreholeFluidSal

inity[kppm]

Porosity [p.u.]



72/125



CNL-16

U-FLT CNL009 Californium 252Open Hole Borehole Fluid Salinity Corrections Centralized Tool

0

50

100

150

200

250


Porosity [p.u.]


0

50

100

150

200

250

-5 0 5 10 15 20 25 30 35 40 45 50 55Boreho

leFluidSalinity[kppm]

Porosity [p.u.]


0

50

100

150

200

250


Porosity [p.u.]



73/125



CNL-17

U-FLT CNL009 Californium 252Open Hole Borehole Mud Density Corrections Eccentralized Tool

1

1.1

1.2

1.3

1.4

1.5

-5 0 5 10 15 20 25 30 35 40 45 50 55

BoreholeMudDensity[g/cc]

Porosity [p.u.]

6.0" Borehole Mud Density Correction

1

1.1

1.2

1.3

1.4

1.5

-5 0 5 10 15 20 25 30 35 40 45 50 55


Porosity [p.u.]


1

1.1

1.2

1.3

1.4

1.5

-5 0 5 10 15 20 25 30 35 40 45 50 55

BoreholeMudDe

nsity[g/cc]

Porosity [p.u.]



74/125



CNL-18

U-FLT CNL009 Californium 252Open Hole Borehole Mud Density Corrections Eccentralized Tool

1

1.1

1.2

1.3

1.4

1.5

-5 0 5 10 15 20 25 30 35 40 45 50 55


Porosity [p.u.]


1

1.1

1.2

1.3

1.4

1.5

-5 0 5 10 15 20 25 30 35 40 45 50 55


Porosity [p.u.]


1

1.1

1.2

1.3

1.4

1.5

-5 0 5 10 15 20 25 30 35 40 45 50 55

BoreholeMudDe

nsity[g/cc]

Porosity [p.u.]



75/125



CNL-19

U-FLT CNL009 Californium 252Open Hole Borehole Barite Mud Density Corrections Eccentralized Tool

1

1.2

1.4

1.6

1.8

2

-5 0 5 10 15 20 25 30 35 40 45 50 55


Porosity [p.u.]

6.0" Borehole Barite Mud Density Correction

1

1.2

1.4

1.6

1.8

2

-5 0 5 10 15 20 25 30 35 40 45 50 55


Porosity [p.u.]


1

1.2

1.4

1.6

1.8

2

-5 0 5 10 15 20 25 30 35 40 45 50 55

BoreholeMudDe

nsity[g/cc]

Porosity [p.u.]



76/125



CNL-20

U-FLT CNL009 Californium 252Open Hole Borehole Barite Mud Density Corrections Eccentralized Tool

1

1.2

1.4

1.6

1.8

2

-5 0 5 10 15 20 25 30 35 40 45 50 55


Porosity [p.u.]


1.0

1.2

1.4

1.6

1.8

2.0

-5 0 5 10 15 20 25 30 35 40 45 50 55


Porosity [p.u.]


1

1.2

1.4

1.6

1.8

2

-5 0 5 10 15 20 25 30 35 40 45 50 55

BoreholeMudDe

nsity[g/cc]

Porosity [p.u.]



77/125



CNL-21

U-FLT CNL009 Californium 252Open Hole Borehole Mud Cake Thickness Corrections Eccentralized Tool

0

5

10

15

20

25

-5 0 5 10 15 20 25 30 35 40 45 50 55

MudcakeThickness[mm]

Porosity [p.u.]

6.0" Borehole Mudcake Thickness Correction

0

5

10

15

20

25

-5 0 5 10 15 20 25 30 35 40 45 50 55

Mudc

akeThickness[mm]

Porosity [p.u.]


0

5

10

15

20

25

-5 0 5 10 15 20 25 30 35 40 45 50 55

MudcakeThick

ness[mm]

Porosity [p.u.]



78/125



CNL-22

U-FLT CNL009 Californium 252Open Hole Borehole Mud Cake Thickness Corrections Eccentralized Tool

0

5

10

15

20

25

-5 0 5 10 15 20 25 30 35 40 45 50 55


Porosity [p.u.]


0

5

10

15

20

25

-5 0 5 10 15 20 25 30 35 40 45 50 55


Porosity [p.u.]


0

5

10

15

20

25

-5 0 5 10 15 20 25 30 35 40 45 50 55

MudcakeThick

ness[mm]

Porosity [p.u.]



79/125



CNL-23

U-FLT CNL009 Californium 252Open Hole Lithology Correction

0

50

100

-5 0 5 10 15 20 25 30 35 40 45 50 55

FormationComposition[%]

Porosity [p.u.]

Lithology Correction

Limestone

SandstoneDolomite


80/125



CNL-24

U-FLT CNL009 Californium 252Open Hole Formation Fluid Salinity Corrections

0

50

100

150

200

250

300

-5 0 5 10 15 20 25 30 35 40 45 50 55

FormationFluidSalinity[kppm]

Porosity [p.u.]

Limestone Formation Fluid Salinity Correction

0

50

100

150

200

250

300

-5 0 5 10 15 20 25 30 35 40 45 50 55

Format

ionFluidSalinity[kppm]

Porosity [p.u.]

Sandstone Formation Fluid Salinity Correction

0

50

100

150

200

250

300

-5 0 5 10 15 20 25 30 35 40 45 50 55

FormationFluidSa

linity[kppm]

Porosity [p.u.]

Dolomite Formation Fluid Salinity Correction


81/125



CNL-25

U-FLT CNL009 Californium 252

Cased Hole Corrections - General

0

1

-5 0 5 10 15 20 25 30 35 40 45 50 55

OH

=0;CH

=1

Porosity [p.u.]

Open Hole to Cased Hole Correction

4

6

8

10

12

14

-5 0 5 10 15 20 25 30 35 40 45 50 55

C

asingOD

[inch]

Porosity [p.u.]

Eccentralized Tool Casing OD Correction

4

6

8

10

12

14

-5 0 5 10 15 20 25 30 35 40 45 50 55

CasingOD

[inch]

Porosity [p.u.]

Centralized Tool Casing OD Correction


82/125



CNL-26


Cased Hole Corrections General

0

50

100

150

200

-5 0 5 10 15 20 25 30 35 40 45 50

ToolTemperature[C]

Porosity [p.u.]

Tool Temperature Correction

0

50

100

-5 0 5 10 15 20 25 30 35 40 45 50 55ToolP

osition[Eccentr.=0]

Porosity [p.u.]

Tool Position Correction (Tool Eccentralized/Centralized in Borehole)


83/125



CNL-27

U-FLT CNL009 Californium 252Cased Hole Corrections Casing Thickness Eccentralized

0.2

0.25

0.3

0.35

0.4

0.45

0.5

-5 0 5 10 15 20 25 30 35 40 45 50 55

Casing

Thickness[inch]

Porosity [p.u.]

4.5" Casing OD - Casing Thickness Correction

0.2

0.25

0.3

0.35

0.4

0.45

0.5

-5 0 5 10 15 20 25 30 35 40 45 50 55

Casi

ngThickness[inch]

Porosity [p.u.]


0.2

0.25

0.3

0.35

0.4

0.45

0.5

-5 0 5 10 15 20 25 30 35 40 45 50 55

Casing

Thickness[inch]

Porosity [p.u.]



84/125



CNL-28

U-FLT CNL009 Californium 252Cased Hole Corrections Casing Thickness - Eccentralized

0.2

0.25

0.3

0.35

0.4

0.45

0.5

-5 0 5 10 15 20 25 30 35 40 45 50 55

CasingThickness[inch]

Porosity [p.u.]


0.2

0.25

0.3

0.35

0.4

0.45

0.5

-5 0 5 10 15 20 25 30 35 40 45 50 55

Cas

ing

Thickness[inch]

Porosity [p.u.]



85/125



CNL-29


Cased Hole Corrections Cement Thickness - Eccentralized

0.1875

0.6875

1.1875

1.6875

2.1875

-5 0 5 10 15 20 25 30 35 40 45 50 55

CementThickness[inch]

Porosity [p.u.]

4.5" Casing OD - Cement Thickness Correction

0.1875

0.6875

1.1875

1.6875

2.1875

-5 0 5 10 15 20 25 30 35 40 45 50 55


Porosity [p.u.]


0.1875

0.6875

1.1875

1.6875

2.1875

-5 0 5 10 15 20 25 30 35 40 45 50 55

CementThickn

ess[inch]

Porosity [p.u.]



86/125



CNL-30


Cased Hole Corrections Cement Thickness - Eccentralized

0.1875

0.6875

1.1875

1.6875

2.1875

-5 0 5 10 15 20 25 30 35 40 45 50 55


Porosity [p.u.]


0.1875

0.6875

1.1875

1.6875

2.1875

-5 0 5 10 15 20 25 30 35 40 45 50 55


Porosity [p.u.]



87/125



CNL-31

U-FLT CNL009 Californium 252Cased Hole Corrections Borehole Water Relative Density - Eccentralized

0.92

0.94

0.96

0.98

1.00

1.02


Porosity [p.u.]

4.5" Casing OD - Borehole Water Relative Density Correction

0.92

0.94

0.96

0.98

1.00

1.02

-5 0 5 10 15 20 25 30 35 40 45 50 55BoreholeW


Porosity [p.u.]


0.92

0.94

0.96

0.98

1.00

1.02


Density[g/cm]

Porosity [p.u.]



88/125


89/125



CNL-33

U-FLT CNL009 Californium 252Cased Hole Corrections Borehole Fluid Salinity Eccentralized

0

50

100

150

200

250


Porosity [p.u.]

4.5" Casing OD - Borehole Fluid Salinity Correction

0

50

100

150

200

250

-5 0 5 10 15 20 25 30 35 40 45 50 55Borehole

FluidSalinity[kppm]

Porosity [p.u.]


0

50

100

150

200

250


Porosity [p.u.]



90/125



CNL-34

U-FLT CNL009 Californium 252Cased Hole Corrections Borehole Fluid Salinity Eccentralized

0

50

100

150

200

250


Porosity [p.u.]


0

50

100

150

200

250

-5 0 5 10 15 20 25 30 35 40 45 50 55Borehol

eFluidSalinity[kppm]

Porosity [p.u.]



91/125


92/125



CNL-36

U-FLT CNL009 Californium 252Cased Hole Corrections Formation Fluid Salinity Eccentralized

0

50

100

150

200

250

-5 0 5 10 15 20 25 30 35 40 45 50 55FormationFluidSalinity[kppm]

Porosity [p.u.]

9.625" Casing OD - Formation Fluid Salinity Correction

0

50

100

150

200

250

-5 0 5 10 15 20 25 30 35 40 45 50 55Formatio

nFluidSalinity[kppm]

Porosity [p.u.]

10.75" Casing OD - Formation Fluid Salinity Correction


93/125



CNL-37

U-FLT CNL009 Californium 252Cased Hole Corrections Casing Thickness - Centralized

0.2

0.25

0.3

0.35

0.4

0.45

0.5

-5 0 5 10 15 20 25 30 35 40 45 50 55


Porosity [p.u.]


0.2

0.25

0.3

0.35

0.4

0.45

0.5

-5 0 5 10 15 20 25 30 35 40 45 50 55

Casing

Thickness[inch]

Porosity [p.u.]


0.2

0.25

0.3

0.35

0.4

0.45

0.5

-5 0 5 10 15 20 25 30 35 40 45 50 55

Casing

Thickn

ess[inch]

Porosity [p.u.]



94/125



CNL-38

U-FLT CNL009 Californium 252Cased Hole Corrections Casing Thickness - Centralized

0.2

0.25

0.3

0.35

0.4

0.45

0.5

-5 0 5 10 15 20 25 30 35 40 45 50 55


Porosity [p.u.]


0.2

0.25

0.3

0.35

0.4

0.45

0.5

-5 0 5 10 15 20 25 30 35 40 45 50 55

Casing

Thickness[inch]

Porosity [p.u.]



95/125


96/125



CNL-40


Cased Hole Corrections Cement Thickness Centralized

0.1875

0.6875

1.1875

1.6875

2.1875

-5 0 5 10 15 20 25 30 35 40 45 50 55


Porosity [p.u.]


0.1875

0.6875

1.1875

1.6875

2.1875

-5 0 5 10 15 20 25 30 35 40 45 50 55


Porosity [p.u.]



97/125



CNL-41

U-FLT CNL009 Californium 252Cased Hole Corrections Borehole Water Relative Density - Centralized

0.92

0.94

0.96

0.98

1.00

1.02


Porosity [p.u.]


0.92

0.94

0.96

0.98

1.00

1.02

-5 0 5 10 15 20 25 30 35 40 45 50 55BoreholeW


Porosity [p.u.]


0.92

0.94

0.96

0.98

1.00

1.02


Density[g/cm]

Porosity [p.u.]



98/125



CNL-42

U-FLT CNL009 Californium 252Cased Hole Corrections Borehole Water Relative Density - Centralized

0.92

0.94

0.96

0.98

1.00

1.02


Porosity [p.u.]


0.92

0.94

0.96

0.98

1.00

1.02

-5 0 5 10 15 20 25 30 35 40 45 50 55BoreholeW


Porosity [p.u.]



99/125



CNL-43

U-FLT CNL009 Californium 252Cased Hole Corrections Borehole Fluid Salinity Centralized

0

50

100

150

200

250


Porosity [p.u.]


0

50

100

150

200

250


Porosity [p.u.]


0

50

100

150

200

250


Porosity [p.u.]



100/125



CNL-44

U-FLT CNL009 Californium 252Cased Hole Corrections Borehole Fluid Salinity Centralized

0

50

100

150

200

250


Porosity [p.u.]


0

50

100

150

200

250

-5 0 5 10 15 20 25 30 35 40 45 50 55Borehole

FluidSalinity[kppm]

Porosity [p.u.]



101/125


102/125


103/125



CNL-47

U-FLT CNL009 Californium 252Cased Hole Lithology Corrections

0

50

100

-5 0 5 10 15 20 25 30 35 40 45 50 55FormationComposition[%]

Porosity [p.u.]

Eccentralized Tool Lithology Correction

Limestone

SandstoneDolomite

0

50

100

-5 0 5 10 15 20 25 30 35 40 45 50 55Forma

tionComposition[%]

Porosity [p.u.]

Centralized Tool Lithology CorrectionLimestone

Sandstone

Dolomite


104/125


Porosity

POR-1

Determination of Density Porosity from Bulk Density

Purpose

This chart may be used to estimate the density porosity given the bulk log density, formation fluid density and

the formation matrix.

Procedure

To estimate the density porosity (D) enter the chart on the horizontal axis at the appropriate bulk density

(B) value as read from the log. Project this line vertically until it intersects the desired matrix curve. Project

the intersection point horizontally to determine the density porosity from the vertical axis.

Example

Given

B= 6.2 g/cm3

f= 1.0 g/cm3

Find

Estimate the density porosity on a limestone matrix.

Answer

From the 6.2 g/cm3 point on the horizontal axis project vertically into the chart until the line intersects the

limestone matrix curve (2.710 g/cm3). At the intersection point project horizontally to read the density

porosity on a limestone matrix of 5 p.u.

Equations

B= log bulk density

f= fluid density in formation

ma= matrix density

D = density porosity

The density porosity can be calculated using the following equation. The result will be in porosity units.

= 100


105/125


Porosity

POR-2

-10

-5

0

5

10

15

20

25

30

35

40

45

50

1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9

DensityPorosity,

D

(p.u.)

Log Density, B (g/cm3)

Density Porosity from Bulk Density

f = 1.0 g/cm3


106/125


Porosity

POR-3

Determination of Density Porosity and Lithology from LDT Log

Purpose

This chart may be used to estimate the density porosity and the lithology of a formation from the Litho-

Density Tool (LDT). There are separate charts for both fresh water (f=1.0) and salt water (f=1.1)

Procedure

Choose the appropriate chart for either fresh (POR 2) or salt water (POR 3) formations. To estimate the

density porosity (D) and lithology enter the chart on the vertical axis at the appropriate bulk density (B)

value as read from the log. Enter the chart on the horizontal axis at the Pe value as read from the log and

project vertically. At the intersection of the two projections read the porosity and lithology.

Example

Given

B= 2.72 g/cm3

Pe = 3.05

f= 1.0 g/cm3

Find

Estimate the density porosity and lithology.

Answer

From the Pe = 3.05 point on the horizontal axis project vertically into the chart until the line intersects the

horizontal projection of the bulk density B = 2.72. At the intersection point read the density porosity and

lithology in this instance to be a Dolomite with a porosity of 8.3 %.

Equations

B= log bulk density


ma= matrix density

D = density porosity

Pe = photoelectric factor

Uf= fluid volumetric photoelectric factor

The bulk density can be calculated using the following equation.

= + (1 )

The Pe is calculated using the following equation.

Where:

Uf= 0.398 barns/cm3for fresh water

Uf= 1.36 barns/cm3for salt water

Pe = ( U) + (1 )(Pe )


107/125


Porosity

POR-4

1.9

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

0 1 2 3 4 5 6

LogDensity,B

(g/cm3)

Photoelectric Factor, Pe (barns/electron)

Porosity and Lithology from LDT Log

f = 1.0 g/cm3

45

45

45

35

40

40

40

30

35

3525

30

30

20

25

25

0

5

15

20

20

10

15

15

5

10

10

10

5

50

0

0

0

5


108/125


109/125


Porosity

POR-6

Mineral Identification Plot (maavs Umaa)

Purpose

This chart may be used to identify formation mineralogy from the apparent matrix density and the apparent

matrix volumetric photoelectric factor.

Procedure

To estimate the mineral type, enter the chart on the vertical axis at the apparent matrix density ( maa) value.

Enter the chart on the horizontal axis at the apparent matrix volumetric photoelectric factor (Umaa) and project

vertically. At the intersection of the two projections determine the percentage of the component minerals.

Note

The effect of gas and barite is to shift the intersection point in the direction shown by the arrows.

A proportionality triangle may be constructed from any three minerals.

Example

Given

maa= 2.73 g/cm3

Umaa= 7.4

Find

Estimate the mineral composition of the formation.

Answer

From the Umaa= 7.4 point on the horizontal axis project vertically into the chart until the line intersects the

horizontal projection of the maa= 2.73. From the intersection point within the triangular area we can see that

the formation is mainly a mixture of sandstone and dolomite.

To obtain more accurate values of the three mineral compositions we can project the intersection point

parallel to the individual mineral component lines to intersect the outer boundaries of the mineral triangle.

The percentage of the individual components is read from the scale on the outer lines. The formation is this

example is approximately 53% sandstone, 33% dolomite and 14% limestone.


110/125


Porosity

POR-7

Equations

log= log bulk density


f= 1.0 g/cm3for fresh water

f= 1.1 g/cm3for salt water

maa= apparent matrix density

= apparent formation porosity

Pe = photoelectric factor

Uf= fluid volumetric photoelectric factor

Uf= 0.398 barns/cm3for fresh water

Uf= 1.36 barns/cm3for salt water

The apparent matrix density can be calculated using the equation:

= ( ( )(1 )

The apparent volumetric photoelectric factor can be calculated using the equation:

U = (Pe ) ( U)(1 )


111/125


Porosity

POR-8

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

4 5 6 7 8 9 10 11 12 13 14 15 16 17

ApparentMatrixDensity,maa

(g/cm3)

Apparent Matrix Volumetric Photoelectric Factor, Umaa

Mineral Identification Plot (maavs Umaa

)

Dolomite

Limestone

Sandstone

Gypsum

Anhydrite

2.0

2.1

9 10 11 12

Orthoclase

Illite

Glauconite

Muscovite Barite

Gas


112/125


113/125


Porosity

POR-10

140 150 160 170 180 190 200 210 220

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

40 45 50 55 60 65 70

ApparentMatrixDensity,maa

(g/cm3)

Apparent Matrix Interval Transit Time, tmaa (sec/ft)

Mineral Identification Plot (maavs tmaa

)

Dolomite

Limestone

Sandstone

Gypsum

Anhydrite

Orthoclase

Muscovite

65 70

2.1

2.0

65 70

2.1

2.0

Apparent Matrix Interval Transit Time, tmaa (sec/m)

65 70

2.1

2.0

65 70

2.1

2.0

65 70

2.1

2.0

65 70

2.1

2.0

65 70

2.1

2.0

65 70

2.1

2.0


114/125


Acoustic

CBL-1


115/125


Crossplot

XPL-1

Porosity and Lithology Determination

Compensated Neutron and Litho-Density Tool

PurposeThese charts may be used to determine the crossplot porosity and lithology mixture of a formation using the

compensated neutron and litho-density logs. Separate charts are presented for both the bulk density and the

density porosity verses the neutron porosity.

Charts for fresh water (f=0, Cf= 0 ppm) and saline fluids (f=1.19, Cf=250 kppm) are available.

Procedure

Enter the chart on the horizontal axis at the apparent limestone neutron porosity and project vertically to

intersect the projection of the bulk density from the vertical axis. The intersection of the two projections

determines the crossplot porosity and lithology mix.

The crossplot porosity is read by drawing a line between matching porosity scales on each of the two lithology

curves.

If the intersection point is between two of the lithology curves then the formation is a mixture of those two

lithologies. The position of the point between the two mineral curves relates the composition percentage of

each mineral by proportioning the composition based on how close the plotted point is to each line. If the line

is closer to one mineral line then there is a greater percentage of that mineral in the composition.

This chart works for formations with up to two mineral compositions. Possible mineral compositions may be:

quartz calcite

quartz dolomite

dolomite calcite

Example

Given

f= 1.0 g/cm3

Cf= 0 ppm

N= 16 % on a limestone matrix

B= 2.36 g/cm3

Find

Determine the crossplot porosity and the lithology mix.

Answer

On the XPL 1 chart project vertically from 16 % porosity on the horizontal axis to intersect the 2.38 g/cm3

projection from the vertical bulk density axis.


116/125


Crossplot

XPL-2

The intersection point lies between the sandstone and limestone curves on the chart as well as between the

sandstone and dolostone curves. The lithology could then be either sandstone and limestone or sandstone

and dolomite.

To determine the crossplot porosity and lithology mix requires that a line be drawn between the sameporosity on the sandstone and limestone curves if the minerals are quartz and calcite (shown by a dashed line)

or between the sandstone and dolostone curves if the minerals are quartz and dolomite (shown by a dotted

line).

If the mineral composition is sandstone and limestone then the crossplot porosity for this example would be

18.5 % with a lithology mix of approximately 63 percent quartz and 37 percent calcite.

If the mineral composition is sandstone and dolostone then the crossplot porosity would be 19 % with a

lithology mix of approximately 84 percent quartz and 16 percent dolomite.

Note

Formation salinity is the total salinity not only the chlorides (typically entered on a mud report).

For NaCl: Total salinity = Chlorides x 1.657


117/125


Crossplot

XPL-3

Anhydrite

Salt

1.8

1.9

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

-5 0 5 10 15 20 25 30 35 40 45 50

Logdensity,

rB

(g/cm3)

CNL Apparent Limestone Porosity,FN (p.u.)

Bulk Density Log and Compensated Neutron Porosity

50

50

45

45

40

40

40

35

35

35

25

30

30

30

25

25

20

10

20

20

15

15

15

10

10

5

0 5

5

0

50

50

45

45

40

40

40

35

35

35

25

30

30

30

25

25

20

10

20

20

15

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15

10

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5

0 5

5

0

50

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45

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40

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35

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25

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10

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15

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10

10

5

0 5

5

0

50

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45

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40

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25

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30

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25

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5

0 5

5

0

50

50

45

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40

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40

35

35

35

25

30

30

30

25

25

20

10

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20

15

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15

10

10

5

0 5

5

0

50

50

45

45

40

40

40

35

35

35

25

30

30

30

25

25

20

10

20

20

15

15

15

10

10

5

0 5

5

0

50

50

45

45

40

40

40

35

35

35

25

30

30

30

25

25

20

10

20

20

15

15

15

10

10

5

0 5

5

0

50

50

45

45

45

40

40

40

35

35

35

25

30

30

30

25

25

20

10

20

20

15

15

15

10

10

5

0 5

0

5

0

rf = 1.0 g/cm3

Cf = 0 kppm


118/125


Crossplot

XPL-4

Anhydrite

Salt

-20

-15

-10

-5

0

5

10

15

20

25

30

35

40

45

50

-5 0 5 10 15 20 25 30 35 40 45 50

Den

sityPorosityinLimestoneUnits,FD(

p.u.)

CNL Apparent Limestone Porosity,FN (p.u.)

Litho-Density Porosity and Compensated Neutron Porosity

rf = 1.0 g/cm3

Cf = 0 kppm

0

20

5

5

5

0

0

50

45

40

35

30

25

20

15

10

10

15

20

25

30

35

40

45

45

40

35

30

25

15

10


119/125

...when expe

AW Log Interpretation Charts

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Transcript of AW Log Interpretation Charts