JCR 7. Advanced Core Measurements. "Best Practices" for Low Reservoir Quality Chalk

Marginal secondary or tertiary chalk reservoirs with lower porosity and very low mobility are becoming
increasingly important for a growing number of mature chalk fields. Significant volumes of hydrocarbons
are often trapped in chalk with low reservoir quality representing an interesting economical potential, but
uncertainty relates to estimation of in-place volumes as well as prediction of reserves and production
profiles. Flow simulation rests on a number of advanced core measurements and many of those have
shown to be intrinsically difficult in low mobility rock giving rise to spurious and less credible data.
Laboratory techniques seem to struggle to acquire reliable data that are representative of in-situ reservoir
conditions in very low mobility/quality chalk.

Under the present Joint Chalk Research Programme, Phase 7 (JCR 7) one of the themes is called "Low
Reservoir Quality Chalk" (LRQC), and the objective is to identify challenges associated with the
development of marginal quality chalk with low porosity/permeability and make steps that may push the
boundary separating prolific chalk and sub-economic chalk. Under this theme, a project called "Advanced
Core Measurements - Best Practices for LRQC" has been approved. This project should define best practices
with respect to core measurements on low mobility rock and thus the project aims at increasing the quality
and consistency of laboratory derived core data. The ultimate goal is to reduce uncertainty associated with
assessment of in-place volumes, production profiles and reserves.

A document should be written to provide guidance to the E&P companies (i.e. to the staff ordering studies)
on what to request with respect to laboratory techniques, procedures, and documentation in order to
obtain data to the current highest standards. The document should further address available techniques
with the view to rank them in terms of data quality, their shortcomings and suggestions for improvement.

The outcome of this project is the present "Best Practices Manual".