Best Practices in Conventional Core Analysis - A Laboratory Investigation

Abstract

Abstract Conventional core analysis procedures were investigated to validate data quality and accuracy. In this paper, 23 core samples from wells Q (14 carbonate samples) and N (9 sandstone samples) were tested in the laboratory. The tests include grain density, porosity, and air and brine permeabilities. Factors investigated in this study are:○Effect of equipment calibration on grain density and porosity measurements,○Effect of drying time on grain density and porosity measurements,○Effect of sleeve confining pressure on gas permeability measurement, and○Comparison between gas and liquid permeabilities. Understanding data acquisition procedures and limitations is very important in core analysis. Therefore, data accuracy in laboratory measurements must be considered. Based on this study, best practices of performing conventional core analysis are recommended. Introduction Laboratory measurement procedures and conditions affect core analysis data quality and accuracy 1. The objective of this paper is to establish best practices based on the analysis of the factors that may affect conventional core analysis measurements, e.g., grain density, porosity and permeability. Accuracy of these rock properties is very important since they are the foundations for geological modeling, reservoir description, reservoir simulation and management. In this study, 23 plug samples were studied, 14 samples from Well Q (carbonate reservoir) and 9 samples from Well N (sandstone reservoir). Basic rock properties were measured (Tables 1 and 2). Data in Tables 1 and 2 indicate that four samples have very low permeability of less than one md and six have very high permeability of more than one Darcy. Such rock samples with extreme permeabilities require extra care in laboratory measurements.