PRESERVATION OF CORE INTEGRITY: A COMPARATIVE STUDY OF CORE STABILIZATION PRODUCTS

摘要

In order to perform representative analyses on reservoir-core samples, the core needs to be protected from mechanical and chemical damage before it reaches the laboratory. Various stabilizing products and techniques are used to hold the core intact within the inner-core barrel. The most common stabilization products used in the industry include epoxy resin, polyester resin, expandable foam and Lithotarge. These products are injected into the annulus between the core and the inner wall of the core barrel. Once set, the core is then prevented from moving in relation to the liner during handling and transportation. However concerns have been raised regarding the wettability and permeability preservation when applying these stabilization products. This paper presents results obtained from laboratory testing of the effect on wettability and permeability resulting from “possible” invasion of these products into the porous rock space. Eight types of sandstones that differ in petrography, porosity (ranging from 18% to 27%), permeability (ranging from 103mD to 2337mD) and wettability have been used in this study. Structural and geochemical analyses have been performed using routine methods. These include petrographical thin sections, Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Environmental Scanning Electron Microscopy (ESEM) and contact angle measurements using a goniometer. Other aspects such as health, environment and safety are briefly discussed. Finally a recommendation for the best non invasive stabilization product that maintains the core integrity is provided.