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

MICP curves - then

MICP curves - now Same reservoir formation – different vintages and equipment and different sample size

Irreducible water saturation, Swirr

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”

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

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 D&C, reservoir engineers and petrophysicists all have different and often conflicting demands for core data. Job of the focal point is to liaise with the stakeholders and the lab and that there is a single point of contact, and to promote a much more pro-active and integrated approach.

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

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

Back Up Slides

Porous plate Pc Semi-permeable membrane Loss of capillary contact 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

Porous plate Pc Semi-permeable membrane Loss of capillary contact 500 Underestimate OIP in Sw-height models 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 400 Air-water capillary pressure (psi) 200 100 Water Saturation (v/v) 0.2 0.8 1.0

Formation factor (F) and ‘m’

Resistivity index (I) and ‘n’

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

SPE August 2010

Example plug history sheet Emphasise details not so important, it can be easily adapted but it presents all data you need to evaluate data and to ensure full audit trail is available for each SCAL plug