Core Analysis Techniques and Applications

Abstract

ABSTRACT Considerations are presented for planning a coring program early in the field development stage. Objectives, currently used coring devices, coring fluids and their suitability are briefly discussed. Precautions in core handling, preservation and selection are reviewed. Types of core analysis are presented, and pertinent observations concerning measurement of porosity, permeability and residual fluid saturations are made. Applications of conventional and special core analysis are briefly discussed. INTRODUCTION Data, its interpretation and its use, forms the basis of any engineering study made to determine in-place hydrocarbon reserves and their most efficient recovery. Conventional core analysis makes an important contribution to the most basic data required - What hydrocarbons, if any, are present, and how much storage capacity (porosity) is available. Lithology of the rock is defined, and deliverability of the formation may be estimated from measured permeability. Examination of residual fluid contents in the core samples allows interpretation of probable production. Study of these basic parameters, coupled with supplementary test data developed on core samples, yields insight into reservoir performance, unusual response to well treatment, and down-hole log interpretation and understanding. Data typically reported and its use are presented in Table 1. Extension of conventional core analysis that furnishes porosity, permeability and saturations to yield more sophisticated data has been accomplished through tests christened 'Special Core Analysis'. These measurements utilize specialized equipment. In most instances, tests of this nature are performed in a central laboratory where special equipment is permanently established, and trained operators familiar with each test are available. Table 2 lists commonly performed special tests.