Estimation of Permeability, Porosity and Rock Compressibility Properties Using Digital Rock Analysis Technique for Heavy Oil Unconsolidated Sandstone Offshore Brazil Post-Salt

Abstract

Mechanical and transport rock properties have fundamental importance to characterize oil and gas reservoirs. Traditionally, these properties are obtained by conventional well logging techniques, seismic inversion and laboratory tests from cores, sidewall cores, plugs and rock cuttings. However, for unconsolidated rocks, conventional recovery techniques of rock samples and performing laboratory tests are subject to failure at all stages of the process. Due to the unconsolidated nature of the rock, the recovery material, are usually changed by fractures created by gas expansion in the oil inside the rock. In addition there are challenges with plugging these rocks, cleaning and conditioning for traditional physical laboratory testing.

In scenario like this, Digital Rock Analysis (DRA) is one of the techniques that have been used to overcome these difficulties. From imaging the rock samples using CT (Computed Tomography - CT), a three-dimensional image of the grain and pore system is created and with new equipment and workflows the rock compressibility properties can be measured.

The aim of this study was develop a rock compressibility methodology using digital image in order to quantify the important reservoir property for improved field development and forecasting reserves.

This paper outlines the equipment designed to allow for scanning the rock samples under hydrostatic pressure using the latest Micro-CT equipment and then taking the different scans and calculating the change in porosity, permeability and other properties. The results of this new work are compared to other available sources including openhole logs with in situ porosity as wells Newman work for rock compressibility assuming uncemented sandstone.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018