1

MICP – typical data on small samples

• Clay destruction/texture alteration – pore volume increases during the test– distorted Pc curves

2

MICP curves - then

3

MICP curves - now

4

Irreducible water saturation, Swirr

KaRQI 0314.0

5

New core acquisition

• What core analysis tests do we need?– don’t pick tests from a menu– review legacy data for uncertainties & gaps

• Is the contractor interpretation correct?– “raw” data needed to check and verify

• Can operators improve on the lab interpretation?– “end users must not abdicate their responsibility

for the interpretation of core data”

6

Planning for core analysis

• Well operations– core bit, mud, tracers,

preservation– core handling and

stabilisation

• Stage analysis program– to suit business needs– flexibility in-built

7

Improved project management

• Project team– The lab is part of the team!

• Single operator focal point

• Real time quality control• Improved documentation

– test specifications & reporting

– invaluable in unitisation

• Key Personnel– Drillers/well operations– Wellsite geologists– Mud engineers– Company geologists– Company petrophysicists– Coring company– Core analysis vendor

Drilling &Completions

Petrophysics & Geology

Reservoir Engineering

Focal point

Laboratory

Drilling &Completions

Petrophysics & Geology

Reservoir Engineering

Focal point

Laboratory

8

Improved core analysis management

• Better core• Coherent and consistent core analysis • Added value

– data redundancy less than 10%• Labs more involved and aligned with

stakeholder objectives• Full data audit trail

– better equity and unitisation positions• Less uncertainty in reservoir models

Price is what you pay. Value is what you get - Warren Buffet

9

Core Analysis: A Guide to Maximising Added Value

Questions & discussionColin McPheeSenergy (GB) Limited

Society of Petroleum Engineers Distinguished Lecturer Programwww.spe.org/dl

10

Back Up Slides

11

Porous plate Pc

• Semi-permeable membrane– capillary contact medium

• Loss of capillary contact– air/oil enters porous plate or contact

medium before sample fully desaturates

• Non-equilibrium saturation– plate permeability is low– brine relative permeability low– drainage through plate is slow

12

Porous plate Pc

• Semi-permeable membrane– capillary contact medium

• Loss of capillary contact– air/oil enters porous plate or contact

medium before sample fully desaturates

• Non-equilibrium saturation– plate permeability is low– brine relative permeability low– drainage through plate is slow0

50

100

150

200

250

300

350

400

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Water Saturation (-)

Air-B

rine

Capi

llary

Pre

ssur

e

Underestimate OIP in Sw-height models

Water Saturation (v/v)0.20 0.8 1.0

Air-

wat

er c

apill

ary

pres

sure

(psi

)

100

200

400

500

13

Formation factor (F) and ‘m’

1

10

100

1000

0.01 0.1 1

Porosity (v/v)

Form

atio

n Fa

ctor

m = 2.10Well 1Well 2Well 3wR

RF 0 mF1

14

Resistivity index (I) and ‘n’

nSwI 1

0RRI t

15

MICP – sample damage

• Clay destruction/texture alteration – pore volume increases during the test– distorted Pc curves

0.1

1

10

100

1000

10000

100000

0 0.2 0.4 0.6 0.8 1 1.2

Volume Injected (ml)

Inje

ctio

n Pr

essu

re (p

sia)

Entry pressureShg = 0 : Swet = 1

Porosity = 0.286 Ka = 2400 mD

Sample damage?

Total pore volume = 0.97 ml

16

SPE August 2010

17

Example plug history sheetSample DetailsWell xx/xx-xxDepth 8820.25 ftMud Type OBMPlug No. PS1.2Core Diameter 4.0 inchesPreparationCut 11/03/2003Cutting Fluid KerosenePlug Diameter 3.81 cmPlug Length 5.74 cmCleaning Method Mild, miscibleSolvents Toluene/MethanolCleaning In 17/03/2003Cleaning Out 23/03/2003Drying HOD (40% RH 60C)Drying In 24/03/2003Drying Out 30/03/2003Initial PoropermDry Weight 144.14 g Cementation ExponentHelium Grain Volume 54.39 cc Stress Pore Volume Bulk Volume Porosity Ro F m Dean-Stark ExtractionHelium Pore Volume 10.67 cc (psi) (ml) (ml) (v/v) (ohm-m) (Ro/Rw) (-) Solvent TolueneMercury Bulk Volume 65.06 cc 0 10.54 64.98 0.162 5.54 28.41 1.84 Initial Weight 143.81 gGrain Density 2.65 g/cc 400 10.2 64.64 0.158 6.76 34.65 1.92 In 15/08/2003Helium Porosity 0.164 v/v 1000 10.1 64.54 0.156 7.39 37.91 1.96 Out 18/08/2003Air Permeability 4.83 mD 2000 9.9 64.34 0.154 7.79 39.93 1.97 Methanol In 18/08/2003Confining Stress 400 psi 3000 9.85 64.29 0.153 8.00 41.03 1.98 Methanol Out 20/08/2003Saturation 4000 9.81 64.25 0.153 8.21 42.10 1.99 Drying Temp. 105 Deg CBrine Type SFW 5000 9.79 64.23 0.152 8.39 43.04 2.00 Drying In 20/08/2003Brine TDS 35,000 ppm 6000 9.74 64.18 0.152 8.47 43.42 2.00 Drying Out 22/08/2003Brine Density at 25 C 1.04 g/cc Final Dry Weight 141.44 gBrine Resistivty at 25C 0.195 ohm-m Saturation Exponent (Air-Water Porous Plate) Water Saturation 0.217 v/vSaturation In 02/04/2003 Stress Pc Time Sw Rt RI Composite Final PoropermSaturation Out 10/04/2003 (psi) (psi) (days) (w/w) (ohm-m) (Rt/Ro) n Helium Grain Volume 53.37 ccSaturation Pressure 22/06/1905 psi 6000 0 2 1 8.47 1.00 1.92 Helium Pore Volume 10.43 ccFinal saturated weight 155.10 g 2 4 1 8.47 1.00 Mercury Bulk Volume 63.80 ccArchimedes Bulk Volume 64.98 cc 5 4 0.593 23.09 2.73 Grain Density 2.65 g/ccResaturation Pore Volume 10.54 cc 10 6 0.469 36.23 4.28 Helium Porosity 0.159 v/vResaturation Porosity 0.162 v/v 25 8 0.337 68.34 8.07 Air Permeability 6.52 mD

50 10 0.287 93.02 10.99 Confining Stress 400 psi100 20 0.244 127.04 15.00