Well Log Interpretation and Petrophysical Analisis in [Autosaved]

Dery Marsan and Ridho Nanda Pratama

Geophysical Engineering – Institut Teknologi Bandung

On Job Training Program – PT.HALLIBURTON LOGGING SERVICE

2015

PT. Halliburton Logging Service is branch of American multinational corporation and one of largest oil field service companies.

Located in Duri, Riau, Indonesia and assist Oil Company in Sumatran Region to perform Completion and Production service, Drilling and Reservoir evaluation.

On Job Training Timeline : August 10th – September 10th 2015

Background

Objective

Basic Theory

Well Data Analysis

Conclusion

• Demand and supply of energy for human daily needs

• Well optimization for stable production

• Requires formation evaluation and petrophysical analysis to interpret well

condition and also reservoir beneath the surface

• Challenge for determining petrophysical parameters

▌ Determining water zone

▌ There are 2 formations will be evaluated

▌ Determining the most suitable Rw and Sw parameters of interest zone from each formation

▌ Analyzing data log by correlating each response curve

▌ Determine Rw and Sw Value in each Interest Zone

OBJECTIVES

CHALLENGES

• Environmental Correction for OH data

• Determine Volume of Shale from GR

• Determine Total Porosity

• Determine Effective Porosity

• Determine a (turtuosity factor), m (cementation factor), and n (saturation

exponent) for Archie’s Formula

• Determine Rw

• Determine Sw

Archie equation developed an experiment based

on clean sand model non-shale content

Only formation water is the only conductive

material inside.

Most of the clastic reservoir rocks have shale

content.

Shale has clay bound water, Archie equation

doesn’t differentiate any kind of water, it treats all

water as the same.

Shale contribute formation conductivity

Archie equation was proposed for clean

sandstone reservoir and need modified equation

to calculate water saturation for shaly sand

formation.

Shaly Sand Reservoir is a

siliciclastic reservoir in which shale

affects reservoir evaluation and/or

reservoir behavior which consist of

mixture of both sand and shale.

E.C Thomas and Sneider Classification

• Caliper log

• Spontaneous potential log

• Radioactive log

gamma ray log

density log

neutron log

• Resistivity Log

induction log

dual laterolog

microresistivity log

• Acoustic log (Sonic log)

• Caliper log measures variations in borehole diameter

with depth, inches as it units.

• Work by recording electrical signal that moved by

arm movements (spring) inside this tools

Application :

• used for formation evaluations to know the

permeability indicator by comparing to bit sizes data

(ex: porous and permeable sandstone, washout

indicator (most in shales) )

• quantify the irregularities for correction

• calculate BHV (Borehole volume)

measuring the difference between voltage in

surface and in downhole with extremely small

amount of voltage (mV). The concept comes

from the difference of concentration ion in

openhole between drilling mud and formation

water.

Application

by using this method we can retrieve

information about:

• identify bed boundaries

• permeability indicator

• shale / non-shale zone (lithology indicator)

• volume of shale indicator

• depth correlation

• Rw calculation

Source of SP signal :

• Electrochemical (produce

>95% signal). Consist of liquid

junction potential and

membrane potential

• Electrokinetic (rare signal)

The magnitude of deflection will

depends on contrast of the

salinity of two liquids

Total deflection measured from

shale base line

Record natural radioactivity in formations,

when the value will increase if

concentration of radioactive material is

high where the common particle is

Thorium, Kalium and Uranium that the

presence is high in shale and low in

sandstone)

Application

by using this method we can retrieve

information about:

• Correlation of depth

• Bed boundaries

• Determining volume of shale

• Indicator of lithology

• Depth control

The concept is bombard the rocks with

radiation and record the amount of

radiation that is not absorbed by

rock,the unit is p.u (porosity unit)

Neutron will be slow if collision with

the particle that have same mass

(example : Hydrogen and Chlorine).

By retrieving information from

hydrogen ions, we can estimate

porosity in formation (direct

measurement).The more particle collision with

matter, the response will become

more low.

Density log is tool that record of formation’s

bulk density by radiating gamma ray into

formation. The unit is g/cc.

The function of this log is to calculate the

porosity, and determining formation density.

Application :

• lithology indicators

• identify certain minerals

• identify overpressure, fracture porosity,

and evaporates minerals.

• detect gas-bearing zone.

Concept: AC current pass through transmitter coil

and create AC magnetic field and give rise induced

eddy voltage loops in formation. And then AC current

flow the induced formations and voltage in receiver

coils.

Problem : requires non-conductive fluid in borehole,

but work in air hole and muds

Application :

• Determine Rt and Sw

• Invasion profiling (diameters, permeability indications)

• Hydrocarbon bearing zone

Environment :

• Fresh water based mud as long as Rmf/Rw > 2.5

• Oil based mud

• Air drilled boreholes

• In salt water-based mud & low contrast Rmf/Rw

Application :

• Determining true formation

resistivity (Rt) for calculating

uninvaded zone saturation

(Sw)

• Identification thin beds

• Determining flused zone

resistivity (Rxo) for calculating

flushed zone saturation ( Sxo)

• Indicate moveable hydrocarbon

(in combo)*

• Estimate diameter invasion (in

combo)*

• Correct deeper reading of

resisvity because effect of

invasion

detect resistivity of a formation in uninvaded

zone.

LLS : (high current frequency) 1050 Hz

Depth of Investigation : 2-3 feet

Vertical Resolution : 2 feet

detect resistivity of a formation in uninvaded

zone.

Frequency : low current frequency 131.25 Hz

Depth of Investigation : 5-7 feet

Vertical Resolution : 2 feet

detect resistivity of a formation which is

closer to borehole.

Application :

• to estimate the depth of fluid invasion

• determine value for flushed zone

resistivity (Rxo)

• to calculating flushed zone water

saturation (Sxo)

Effective porosity equation :

Ratio Method

SP Method

Archie Equation

Simandoux Equation

Indonesia Equation

(Sasha Reference Manual, 2013)

RMF 0.07 Ohm m

RMF @ Temp 80.5 F

Total Depth 1539 feet

Bottom Hole

Temp150 F

Surface Temp 82.5 F

Processing

Interval4 Feet

▌ Environmental Correction

▌ Quick Look Interpretation

▌ Determine Vsh

▌ Determine Effective porosity

▌ Calculating Rw

▌ Sw Calculation

Based on:

• GR Log, interval consist of shale zone

and non shale zone

• SP log, at non shale zone for all

formation has negative deflection,

Rw>Rmf, fresh water in formation

• Caliper log, at non shale part it shows

mudcake (less than 8.5’’) that means

permeable zone and shale part shows

washout (more than 8.5 ‘’)

• Separation between MSFL and DLL log

almost apear at all interval which

means good permeability.

• Pe, range between 2-4, some part

contain shale zone and sandstone zone

and shaly sandstone as well

• Density-Neutron, separation between

both log at shale zone, almost stack in

sand interval which means waterzone,

and probably HC. Separation that show

butterfly effect highly identified as gas

bearing zone.

Analysis Depth 556 feet

Interval Analysis 4 feet

Formation A 900-1166 (266 Ft)

Formation B 1166 - 1456 (290 Ft)

Formation A :

shale dominated, shaly

sand reservoir

Formation B:

clearly to determine

reservoir zone and shale

zone

WATER BEARING ZONE

FormationRatio

Method

Inverse

Archie

Method

SP

Method

A 0.289860964 1.575997521 0.039062

Water Bearing Zone (1086-1091 ft)

• Lower GR

• Permeable zone (separation, SP, mudcake)

• Deflection response in Resistivity

• Pe value is close to 2.1 (sandstone with shale

effect)

• Neutron-Density almost stack each other

RwArchie

Equation

Simandoux

Equation

Indonesia

Equation

Inverse 1 0.940377 0.679455

SP 0.157434 0.164983 0.154414

RATIO 0.428862 0.433977 0.368047

FormationRatio

Method

Inverse

Archie

Method

SP

Method

B 0.588504195 2.283667181 0.042503


• Lower GR

• Permeable zone (separation, SP, mudcake)

• Low curve response in Resistivity

• Pe value is close to 2.0 (clean sandstone)


RwArchie

Equation

Simandoux

Equation

Indonesia

Equation

Inverse 1 1.043928 0.516518

SP 0.136425 0.170943 0.146134

Ratio 0.507643 0.587798 0.372039

WATER BEARING ZONEDepth

Density

porosity

Neutron

Porosity

Total

Porosity

Effective

Porosity

1086-1091 0.24242424 0.372 0.307212 0.228615

RWWater Saturation

Archie Simandoux Indonesia

Archie 1.020766 0.742287662 0.580337134

SP 0.160703 0.199420508 0.17964779

Ratio 0.437767 0.431702805 0.364171124


• Lower GR

• Permeable zone (separation, deflection in

SP, has mudcake on caliper log)




OIL BEARING ZONE

WATER BEARING ZONE

Oil Bearing Zone (1166-1189 ft)

• Lower GR

• Permeable zone (separation, deflection in

SP, has mudcake on caliper log)

• High curve response in Resistivity




• Lower GR

• Permeable zone (separation, deflection in SP,

has mudcake on caliper log)




OIL BEARING ZONE

WATER BEARING ZONE

DepthDensity

porosity

Neutron

Porosity

Total

Porosity

Effective

Porosity

1166-1189 0.32323232 0.365 0.344116 0.272849

1189-1217 0.33333333 0.3705 0.351917 0.263166

RWWater Saturation


Archie 1.478501 0.755435071 0.650912958

SP 0.232766 0.440332997 0.372657851

Ratio 0.634072 0.640019975 0.540872593

RWWater Saturation


Archie 0.888042 0.90969247 0.464719272

SP 0.12115 0.150415762 0.129376124

Ratio 0.450808 0.514985349 0.33234166

OIL BEARING ZONE

DepthDensity

porosity

Neutron

Porosity

Total

Porosity

Effective

Porosity

1250-1265 0.24418605 0.284090909 0.341 0.31267

RWWater Saturation


Archie 0.841112 0.753672841 0.411575334

SP 0.114748 0.171353274 0.13220247

Ratio 0.426985 0.485346662 0.300712135

Oil Bearing Zone (1250-1265 ft)

• Lower GR






GAS BEARING ZONEDepth

Density

porosity

Neutron

Porosity

Total

Porosity

Effective

Porosity

1310-1334 0.35858586 0.175 0.287403 0.2412

RWWater Saturation


Archie 0.410042 0.297849671 0.198358619

SP 0.05594 0.068036849 0.058469459

Ratio 0.208155 0.197823305 0.142845177

Gas Bearing Zone (1310-1334 ft)

• Lower GR





• Neutron-Density stack each other, and show

butterfly effect area

GAS BEARING ZONE

DepthDensity

porosity

Neutron

Porosity

Total

Porosity

Effective

Porosity

1385-1424 0.34435262 0.2030.28602

20.23434

RWWater Saturation


Archie 0.479837 0.367534936 0.231584102

SP 0.065461 0.084017427 0.070268843

Ratio 0.243586 0.242422956 0.167927319

Gas Bearing Zone (1385-1424 ft)

• Lower GR





• Neutron-Density stack each other and show

butterfly effect

Inverse Archie method is more suitable to determine Rw value forboth of this formation

Sw method that compatible for this well is Archie Equation andIndonesia Equation (for A formation).For B formation, the suitableones is Simandoux and Archie Equation

There are identified potential HC zone which contain gas or oil:

Oil : 1166-1189 ft, 1250-1265 ft

Gas : 1310-1334 ft, 1385-1424ft

Another data and method improvement is needed for crosscheckdata and get better result

API No. N/A Other Services:

GR/SFTT

Location N : X GR/SWC

E :Y

LAT : A

LOT : B

Permanent Datum G.L. Elev. 106.6 ft Elev.: K.B. 127.1 ft

Log measured from O.R.T. 19.5 ft above perm. Datum D.F. 126.1 ft

Drilling measured from O.R.T. G.L. 106.6 ft

9.625 in @ 983.0 ft

12.250 IN 983.00 ft

0.197 ohmm 75.30 degF

0.13 ohmm 75.80 degF

0.216 ohmm 78.80 degF


8-Aug-13 10:04

223 degF @ 5638.0 ft

H A LLIB U R T O N

COMPANY

WELL

ALFA CENTAURY

Saturnus #123

TRIPLE COMBO

1:200 (MD)

PT

. C

HE

VR

ON

PA

CIF

IC

IND

ON

ES

IA

PT. CHEVRON PACIFIC INDONESIA

Saturnus #123

ALFA CENTAURY

RIAU COUNTRY INDONESIA

Source of Sample

WE

LL

FIE

LD

PR

OV

INC

E

FIELD

PROVINCE

CO

UN

TR

Y

CO

MP

AN

Y

Date

Run No.

Sa

turn

us #

12

3

ALF

A C

EN

TA

UR

Y

RIA

U

IND

ON

ES

IA

Bit Size

Type Fluid in Hole

Depth - Driller

Depth - Logger

Casing - Driller

Witnessed by

8-Aug-13

ONE

5678.00 ft

5638.0 ft

5632.0 ft

983.0 ft

983.0 ft

8.500 in

Bottom - Logged Interval

Top - Logged Interval

Casing - Logger

DIONYSIUS ANGGA

@

Density

PH

Viscosity

KCL - POLYMER

FLOWLINE

Time Since Circulation

Time on Botom

Max. Rec. Temperature

Recorded by

Equipment Location

Rm @ Meas. Temperature

Rmf @ Meas. Temperature

MR. CHANDRA WINATA

T-1475 CAS

16.1 hr

MEASURED MEASURED

@

Rmc @ Meas. Temperature

Rm @ BHT

Source Rmf Rmc

Fluid Loss

9.4 ppg

9.00 pH

59.00 s/qt

4.9 cptm

@

@

@

@

@

@

@

@

@

@@

@

@

@

@ @

0.197 ohmm 75.30 degF


0.216 ohmm 78.80 degF


8-Aug-13 10:04

223 degF @ 5638.0 ft

Source of Sample

Bit Size

Type Fluid in Hole

8.500 in

@

Density

PH

Viscosity

KCL - POLYMER

FLOWLINE

Time Since Circulation

Time on Botom

Max. Rec. Temperature

Rm @ Meas. Temperature

Rmf @ Meas. Temperature

16.1 hr

MEASURED MEASURED

@

Rmc @ Meas. Temperature

Rm @ BHT

Source Rmf Rmc

Fluid Loss

9.4 ppg

9.00 pH

59.00 s/qt

4.9 cptm

@

@

▌ GR was corrected to borehole diameter, mud density & tool

position.

▌ Resistivity was corrected to borehole temperature, borehole

diameter and bed thickness

▌ Micro Resistivity was corrected to mudcake resistivity at formation

temperature and mudcake thickness

▌ Neutron Porosity was corrected to mudcake thickness, borehole

salinity, natural or barite mud density, formation temperature and

pressure

▌ Density was corrected real time during logging

Based on:

• GR Log, interval consist of shale zone and non

shale zone

• SP log, at non shale zone for all formation has

negative deflection, Rw>Rmf, fresh water in

formation

• Caliper log, at non shale part it shows mudcake

(less than 8.5’’) that means permeable zone and

shale part shows washout (more than 8.5 ‘’)

• Separation between MSFL and DLL log almost

apear at all interval which means good

permeability.

• Pe, range between 2-4, some part contain shale

zone and sandstone zone with probably contain

shale and calcareous.

• Density-Neutron, separation between both log at

shale zone, almost stack in sand interval which

means waterzone, and probably HC

Water Bearing Zone (5480 – 5516 ft and 5544 –

5560 ft)

• Lower GR

• Resistivity slighlty lower than other sand body

• Pe value is close to 1.8 (sandstone)


(Neutron slightly to right of density)

Shale Zone (4900 – 5450 ft)

• Higher GR

• Resistivity and MSFL curve quite stack

• Lower Resistivity

• Pe value between 2.5-4

Oil Bearing Zone (5456 - 5480 ft)

• Lower GR

• Higher Rsesistivity

• Pe value is close to 2 (sandstone)


(Neutron slightly to right of density)

Water Bearing Zone

Shale Zone

Oil Bearing Zone

Water Bearing Zone

DepthDensity

porosity

Neutron

Porosity

Total

Porosit

y

Effectiv

e

Porosit

y

5456 –

54800.245 0.258 0.252 0.205

Oil Bearing Zone

Rw

calculation

method

Sw ArchieSw

Simandoux

Sw

Indonesia

Rwa

(=2.299)0.4248 0.09559 0.1942

Rw SP

(=0.152)0.4248 0.0714 0.0584

Rw Ratio

(=0.765)0.4248 0.0921 0.1396

Water Bearing Zone

Water Bearing Zone

DepthDensity

porosity

Neutron

Porosity

Total

Porosi

ty

Effective

Porosity

5480 – 5516 0.247 0.254 0.251 0.2065544 – 5560 0.226 0.262 0.244 0.214

Rw

calculation

method

Sw ArchieSw

Simandoux

Sw

Indonesia

Rwa (=2.299) 1.0105 0.330024 0.41753

Rw SP

(=0.152)1.0987 0.2706 0.1504

Rw Ratio

(=0.765)1.0987 0.4887 0.3611

Conclusion

1. Sw method that compatible for this well is Archie Equation (clean sand part) and

Simandoux Equation (for shale part)

2. In “A” Formation there are:

Oil bearing zone at 5456 – 5480 ft

Water bearing zone at 5480 – 5516 ft and 5544 – 5560 ft

Suggestion

1. Shaly sand analysis study would be better if compared to core data

and thin section to know clay distribution that more reliable

Well Log Interpretation and Petrophysical Analisis in [Autosaved]

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