MICP typical data on small samples Clay destructiontexture

MICP – typical data on small samples • Clay destruction/texture alteration – pore volume increases during the test – distorted Pc curves 1

MICP curves - then 2

MICP curves - now 3

Irreducible water saturation, Swirr 4

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” 5

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 6

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 7

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 8

Core Analysis: A Guide to Maximising Added Value Questions & discussion Colin Mc. Phee Senergy (GB) Limited Society of Petroleum Engineers Distinguished Lecturer Program www. spe. org/dl 9

Back Up Slides 10

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 11

Porous plate Pc 500 Air-water capillary pressure (psi) Underestimate OIP in Sw-height models • Semi-permeable membrane – capillary contact medium 400 • Loss of capillary contact – air/oil enters porous plate or contact 200 medium before sample fully desaturates • 100 Non-equilibrium saturation – plate permeability is low – brine relative permeability low is slow 0– drainage 0. 2 through Waterplate Saturation (v/v) 0. 8 1. 0 12

Formation factor (F) and ‘m’ 13

Resistivity index (I) and ‘n’ 14

MICP – sample damage • Clay destruction/texture alteration – pore volume increases during the test – distorted Pc curves 15

SPE August 2010 16

Example plug history sheet 17