Introduction to Wireline Engineeringand its application to Formation Evaluation

Asfan Hasbiantoro

Personal Introduction

Asfan Hasbiantoro

Yogyakarta, Jan 25th , 1979

Gadjah Mada University, 1997-2002.

2002-2004 Sumatra, Wireline Engineer, Schlumberger

2005-2008 Mumbai, Wireline Engineer in Charge, Schlumberger

2008-2010 Sudan, Field Service Manager, Schlumberger

2010-2013 Jakarta, Account Manager, Schlumberger

2013-Now Jakarta, Director, PT Iliadi Cipta Energi

Introduction

Which one will you pick ??

Oil Well Life Cycles

Goal of Formation Evaluation

• To evaluate the presence or absence of

commercial quantities of hydrocarbons in

formations penetrated by, or lying near the

wellbore.

• To determine static and dynamic

characteristics of productive reservoir.

• To detect small quantities of hydrocarbon

which nevertheles may be very significant from

an exploration standpoint.

• To provide a comparison of an interval in one

well to the correlation interval in another well.

Evaluation Sequence

Reservoir or Non-Reservoir

Hydrocarbon or Water

Gas and or Oil EVALUATE

Locate the Reservoir

Detect the Hydrocarbon

Differentiate between Gas

Oil

Formation Evaluation is Critical

to understand the Reservoir

• Hydrocarbon Thickness

• Porosity

• Saturation

• Area

• Hydrocarbon type

What is the value of Hydrocarbon in Place

(Hydrocarbon Potential)

• Permeability

• Pressure

How easily can Hydrocarbon can flow

out the well

• Lithology

• Depth, Pressure, Temperature

How easy is it to drill to the reservoir (cost of drilling, completions,

etc ..)

Formation Evaluation Methods

• Mud Logging

• Coring

• Wireline Logging

• Testing and Sampling

Mud Logging

• A well logging process in which drilling

mud and drill bit cuttings from the

formation are evaluated during drilling and

their properties recorded on a strip chart

as a visual analytical tool and stratigraphic

cross sectional representation of the well.

Conventional Coring

• Coring - Conventional Taking a core requires that the regular drill bit be removed from the hole. It is replaced with a "core bit", which is capable of grinding out and retrieving the heavy cylinder of rock.

• The core bit is usually coated with small, sharp diamonds that can grind through the hardest rock. A core bit cuts very slowly.

• A core is a solid cylinder of rock about 4-5 inches in diameter, and a single core will usually be about 30 feet long.

Side Wall Coring

• This method is cheaper than

the conventional coring

• Cores can be taken in

hours, instead of days

• In sidewall coring, a slim

wireline coring tool is run

into the hole. The tool may

be of two general types;

either "rotary sidewall" or

"percussion“

• Typically, cores about 1" in

diameter and 1" to 2" long

can be retrieved with this

method.

Wireline Logging

• What :

• In situ (vs Depth) measurement of Rock and

Fluid Properties

• When :

• Open Hole (before casing set) :

– While drilling (LWD)

– After Drilling (Wireline)

• Cased Hole

– Analysis Behind Casing (CO Log, etc)

– Production Logging

• Interpretation for :

• Geological properties

• Geophysical properties

• Petrophysical properties

• Reservoir properties

Testing (Drill Stem Testing)

and Sampling

• Used to provide a more definitive idea of the production capacity of the well

• Drill Stem Tests identify the types of fluids within the well, as well as the flowrate of these fluids, formation permeability and reservoir pressure.

• Drill stem tests involve connecting a measurement device to the bottom of the drill stem, also in place of the drillbit, and lowering the system into the well, all the way to the formation.

• The instrument is activated at the bottom of the well, measuring the flow of oil or gas for a specified amount of time, usually on hourly basis.

Wireline Logging

Well Logging (WIRELINE)

Well Logging data is critical to

have for Formation Evaluation

Reservoir or Non-Reservoir

Hydrocarbon or Water

Gas and or Oil EVALUATE

Locate the Reservoir

Detect the Hydrocarbon

Differentiate between Gas Oil

• Hydrocarbon Thickness

• Porosity

• Saturation

• Area

• Hydrocarbon type

What is the value of Hydrocarbon in

Place (Hydrocarbon Potential)

•Permeability

•Pressure

How easily can Hydrocarbon can flow out the well

•Lithology

•Depth, Pressure, Temperature

How easy is it to drill to the reservoir

(cost of drilling, completions, etc ..)

Value and Limitation Wireline Log

DataValue Limitation

Provide remotely sensed value of

reservoir properties and fluids

Indirect measurement

Among the most abundant reservoir

data

Vertical resolution

Presentation result fairly standardized Depth of investigation

Allow evaluation of lateral (map) and

vertical (cross section) changes in

reservoir data

Wireline Logging Data User

Wireline logging output can be used in a

number of ways by a number of people to

provide solutions to questions they have about a

particular well. Some of the ways different

people in an office will use these logs are:

Geophysics look to logs for:

– Where are my tops (as predicted?)

– Does seismic interpretation agree with log

data?

– How is my synthetic doing with this new

information?

Geologists look to logs for:

– Where are my tops ?

– Do I have any reservoir ?

– Is there any Hydrocarbon in the well ?

– What type of Hydrocarbon(s) is there ?

– How good is my reservoir ?

– What kind of reserves do I have ?

– How does this tie in to my offsets ?

Drilling Engineers are looking for:

What is my hole volume (cement) ?

What is my dog leg severity ?

Where can I get a good packer seat for testing ?

Where can I set up my whipstock ?

Production Engineers are looking for:

Where should complete this well ?

What will be my expected production rates ?

Will I have to deal with water ?

How should I complete this well ?

Do I need to stimulate this well ?

How should I stimulate it ?

Wireline Log Type

Typically Wireline Logging data classified into 3 board categories depending on well condition logged :

• Open Hole : Log which done right away after drilling process completed prior to case the well.

• Cased Hole : Log done after well been cased

• Production Log : Log done after well been produced or fluid flowing

Open Hole Logging Measurement

• Caliper

• Resistivity Logs (Microresistivity, Laterolog, Induction)

• Radioactive Logs (Gamma Ray, Neutron Porosity,

Density Porosity)

• Sonic / Accoustic Logs (Monopole and Dipole Sonic)

• Magnetic Resonance

• Dipmeter Logging

• Pressure Testing and Sampling

Cased Hole Logging Measurement

• Radioactive Log

– Gamma Ray

– Neutron Porosity

– Carbon-Oxygen Log

• Sonic / Accoustic Log

– Cement Bond Log / Ultrasonic log

Production Logging Measurement

• Nuclear (Gamma Ray)

• Flow meter

• Hold up meter

• Pressure

• Temperature

Open Hole Wireline Logging

Resistivity

• Resistivity-Saturation Relation

Water

Wat er

Hydrocarbons

Water

Matrix

Water

Hydrocarbons

Matrix

Rt Rw

Rt 1/ Sw

Rt 1/F

Rt Sw F

Rw

Rt =Rw

Fn

Sw

ma

Mud Invasion Profile

COMMON TERMINOLOGY

• Borehole

• Rm : Borehole mud resistivity

• Rmc : Mudcake resistivity

• Invaded zone

• Rmf : Mud filtrate resistivity

• Rxo : Invaded zone resistivity

• Sxo : Invaded zone water saturation

• Uninvaded zone

• Rw : Interstitial water resistivity

• Rt : Uninvaded zone resistivity

• Sw : Uninvaded zone water saturation

Laterolog Resistivity

• Current lines parallel and radial outwards

• Represents tool in a borehole

• Io = Total Current DV = V0 - VV0

• Resistivity = K V0/I0

• K = Geometrical Factor --- Cylinder

I0

V= V0V= 0

L

r

Induction Resistivity

• Laterolog used in

conductive mud

environment, Induction

tool used in non-

conductive mud

environment.

Radioactive (Gamma Ray)

• The Gamma Ray log is a measurement of the formation's natural radioactivity.

• Gamma ray emission is produced by three radioactive series found in the Earth's crust.

– Potassium (K40) series.

– Uranium series.

– Thorium series.

• Gamma rays passing through rocks are slowed and absorbed at a rate which depends on the formation density.

• Less dense formations exhibit more radioactivity than dense formations even though there may be the same quantities of radioactive material per unit volume.

Natural Gamma Ray

• The tool reacts if the shale is

radioactive (usually the case), hence

show the sands and shales, the

permeable zones and the non-

permeable zones.

• Computation of the amount of shale:

The minimum value gives the clean

(100%) shale free zone, the maximum

100% shale zone. All other points can

then be calibrated in the amount of

shale.

Radioactive (Neutron)

• Why Radioactive Neutron Measurement ?

• How Neutron measurement related to Porosity?

Rt =RwF

nSw

ma

NeutronSource

Short SpacedDetector

Long SpacedDetector

Borehole

Formation

ThermalPhase

NEUTRON

SOURCE

TIME ( µ s)

CAPTUREAVERAGE

THERMAL

ENERGY.

025 EV

.4 eV

10 eV

100

ENERGY LEAVING SOURCE

1 10

01

1

102

104

106

APPROX.

EPITHERMAL

ENERGY

REGION

NE

UT

RO

N E

NE

RG

Y (

e V

)

Diffusion & Capture

Slowing down

Neutron Porosity

• HYDROGEN very effective in slowing down

Neutrons

• commonly found in formation fluids

• CHLORINE is a good absorber (Capture)

• dissolved salts in formation water

• CADMIUM - excellent as a shield

Element

Atomic No.

Element

Symbol

Capture

Cross Section

(Barns)

Scattering

Cross Section

(Barns)

Average No. of

Collisions to reduce

Neutron energy from

2MeV to 0.025eV

1 H 0.3 20 18

6 C 0.0032 4.8 115

8 O 0.0002 4.1 150

14 Si 0.13 1.7 261

17 Cl 31.6 10 329

48 Cd 2500 5.3 1028

Neutron Porosity

Summary

HGNS detects “ Thermal “ neutrons .

>“ Hydrogen Index “ .

>Porosity and Gas content.

Why ?

Pore Space is filled with fluids (commonly water, oil and gas)

Formation fluids contain hydrogen

Hydrogen has a high scattering X-section

Gas has a low concentration of hydrogen

Chlorine (common in water) has a high capture X-section

How?

A two detector system reduces environmental effects

The ratio of Near (cps) over Far (cps) is related to H.I.

Radioctive Density

• Density measurement is as important as Porosity Measurement

(Formation Density 1/Formation Porosity)

• Density Tool measure Formation Density through Measuring

Electron Density in the formation

• GR Interaction : Compton Scattering

2650 Kg/m3 2485 Kg/m3 2320 Kg/m3 2145 Kg/m3>>>

Formation Density gm/ cc PEF

Sandstone 2.65 1.8

Limestone 2.71 5.1

Dolomite 2.81 3.1

Anhydrite 2.98 5.1

Salt 2.03 4.6

Shale 2.1 – 2.8 1.8 – 6.3

Sonic Logging

• Mechanical property analysis

– sanding analysis

– fracture height

– wellbore stability

• Formation evaluation

– gas detection

– fractures

– permeability

• Geophysical interpretation

– synthetic seismograms

– VSP

– AVO

Compressional

body wave

Compressional

head waves

Shear head wave

Shear body wave

Sonic Logging –

Dynamic Elastis Property

v Poisson’s Ratio

G Shear Modulus

E Young’s Modulus

Kb Bulk Modulus

Cb Bulk Compressibility

(with porosity)

Lateral strain 1/2 (DTS / DTC) 2 – 1

Longitudinal strain (DTS / DTC) 2 – 1

Applied stress pb

Shear strain DTS 2

Applied uniaxial stress

Normal strain 2G (1 + v)

Hydrostatic pressure

Volumetric strain

1 4

DTC2 3DTS2[ ]x a

Volumetric deformation

Hydrostatic pressure

1

Kb

pb

Magnetic

Resonance

• Nuclear Magnetic

Resonance logging utilizing

magnetic to manipulate

hydrogen atom in fluid

which resulting T2

amplitude indicate

permeability measured fluid.

0

5

10

15

20

25

30

0.0 0.2 0.4 0.6 0.8 1.0

sig

nal a

mp

litu

de

time (sec) 0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0.3 0.5 0.7 0.9 2.0 4.0 6.0 8.0 10.0 30.0 50.0 70.0 90.0 200.0 400.0 600.0 800.0 1000.0 3000.0

no

rma

lize

d s

ign

al a

mp

litu

de

T2 (ms)

Magnetic Resonance Logging

Porosity = 20%

Permeability= 7.5 md

Porosity = 19.5%

Permeability= 279 md

T2 timek = 279 md

Signaldistribution

Increasing relaxation time

T2 timek = 7.5 md

Signaldistribution

Increasing relaxation time

Dipmeter Logging and Borehole Imaging

• High resolution electrical image

• Structural analysis (structural dip, faults,

fractures, complex structures)

• Rock Sedimentary Features (sedimentary dips, anisotropy & permeability barriers, thin beds analysis)

• Evaluate Rock Textures

• Depth matching, orientation and substitution of cores

Dipmeter Logging

0 10 20 30 60 90

Dip magnitude

Dip azimuth

Pressure Test and Sampling

• Pressure Test logging on wireline done thru Logging tools which designed to have packer and probe as formation fluid inlet, for pressure measurement or sampling

• Latest advancement on Fluid Analyzer module has made possibility to do ‘lab work’ downholewithout sampling the formation fluid.

Fluid Analyzer

Spectrometer

(Gas Analyzer)

Sample Flow

Fluorescence Detector

Lamp

Flowline

Production Logging

Production Logging

• Measurement of fluid

parameters zone by zone

basis to yields information

about the type and

movement of fluid within and

near wellbore.

Applications

• Evaluation of Completion Performance

– Perforation effectiveness

– Stimulation evaluation

– Formation damage identifications

• Monitor Reservoir Performance and variations

– New well performance vs prediction

– Time lapse profile monitoring

– Layered Reservoir Testing

• Diagnose Well Problems

– Source of high : Gas to Oil Ratio or High Water Cut

– Detection of leaks or crossflow

– Flow behind casing

• Others

– Guidance for workover planning

– Improved/Enhanced Oil Recovery Projects

– Identify boundary for field development

Production Logging Sensor

Casing Collar Locator

Gamma Ray Detector

Telemetry

Interfaces

Optional

Sensors

-Gradiomanometer

-Pressure

-Temperature

Flowmeter (fullbore)

Standard

Sensors

Quartz Pressure

Gauge

Caliper

In line flowmeter

Petal basket flowmeter

Nuclear Fluid

Densitometer

Hold-Up Meter

O- Probes (GHOST)

E- Probes (FloView)

Noise Tool

Tracer Ejector

Special

Applications

PVL/WFL

Special

Applications

Basic Interpretation

• Monophase Flow Rate

= Velocity x Area Q=VxA

• Multiphase Flow Rate

= Phase Velocity x Phase Area

= Phase Velocity x (Area x Phase Hold

Up)

VhyVw

PL Sensor Output

• Mixture Velocity

– Spinner

• Hold Up

– Fluid Density, Capacitance,

Local Probes

• Phase Velocity

– Correlations

Gradiomanometer Nuclear Capacitance Probe Tools

Hold Up Concept

- Hold up is a DOWNHOLE measurement:- Area fraction of the pipe occupied by the phase of interest.

• For oil-water flows: yw + yo = 1

• For oil-water-gas flows: yw + yo + yg = 1

Water holdup = volume of water

total volume

- Water cut is a SURFACE measurement:- Ratio of flowrates. For instance in an oil-water flow, water cut is

given by –

• WC (%) = qw/(qo + qw)

• and more generally by:

• WC (%) = qw/qt

Water-cut = Volume of water

Total liquid

Water Holdup Water Cut

Flowmeter

• Continuous

Spinner Not collapsible

Measurements in Tubing &

Casing

Not sensitive to small flow

variations

Low resolution

• Fullbore SpinnerMeasurements in Casing only

Maximum CSID coverage

Collapsible

Very sensitive

High resolution

E-Probe (Flowview)

Ground electrode

(For oil continuous phases)

Conductive Tip

Ground electrode(for oil continuousphase)

• Four probes sense local fluid impedance

• Oil and gas -- > high electrical impedance

• Water --> low electrical impedance = fn(salinity)

• Computations:

• Probe architecture

Water Holdup =Time in low impedance

Total time1.

2. Bubble count = Number of transitions

Total time

O-Probe (GHOST)

Gradiomanometer

Output : Fluid Density

Application :

• Fluid Type Determination

• Hold up calculation

• Hydrostatic Pressure

Measurement

• Pa = Pb + (pfluid x g x h) P1

P2

Diaphragm

h

PA

PB

Silicone

Oil

Wellbore

fluid

Typical PL Program• Shut-In conditions

- RIH and ….• Determine fluid levels

• Detect Cross-flows (if any)

• Get a BASE log (eg.Temp)

• Flowing conditions

- Wait for stable flow

pressure, spinner, density ?

- Wait for well stabilization

Required for WT jobs

- Log interval of interest

Flowing profile & cross-flow

Fluid entries

- Log stations if requested

Flow Profile (ex. 1)

• Well flowing at constant

choke:– Zone Contribution

– Downhole reservoir data

– Absorption profile for injector wells

– Identification of production

problems

• Different flowing Choke:

- Selective inflow performance

surveyGas

OIL

Water

spinner density

Temperature

Flow Profile (ex. 2)

• Well shut in – Flow between two

perforation (Reservoir

pressure difference)

Gas

OIL

Water

spinner density

Temperature

Sump

water

Conclusion

• Wireline Engineering application to Formation

Evaluation is critical factor for evaluating commercial

content Hydrocarbon in reservoir

• Formation Evaluation source of data can be

gathered from many sources : Mud Logging, Coring,

Wireline Logging, Pressure Test and Sampling

• More data can be collected more precise decision

can be made and minimize formation uncertainty