Core Analysis: An Introduction

Abstract

Cores are a fundamental source of information for exploration, evaluation, development, and production of any hydrocarbon field. Cores are a unique source of some datatypes such as rock textural parameters or permeability. They can be calculated or estimated based on other data sources and cannot be gained directly from those data. Some others, such as porosity, are calibrated against core analysis results. Cores are direct samples from the reservoir rocks that can be tested, analyzed, and viewed by the researcher. A core analysis project starts from the coring plan, coring, and core preservation, and continues with three main phases including routine, geological, and special core analysis. Some additional stages are also included such as geomechanics or geochemistry. Various experts are involved in a core planning task. They consider all variables including requirement, cost, and risk to decide the different aspects of coring and core analysis. After coring, cores are transferred to the laboratory. Core analysis starts with the core gamma logging and whole core CT-scanning. Basic petrophysical parameters using single-phase fluid are measured on the cores in the routine stage. This step also includes core handling and preparation for routine, special, and geological analysis. Geological analysis includes thin section preparation, microscopic and macroscopic studies, and rock typing. Final data are compared with the wire line logs and distributed to the interwell space. Dynamic data are provided using multiphase fluid tests in a special section. All data are integrated to reconstruct the rock and fluid distribution within the reservoir.