water shut off, profile modification, polyacrylamide, HPAM, PPG
Excess water production due to conformance problems is a serious issue in oil extraction with severe environmental and economic implications. This is mainly due to the heterogeneity of the reservoir and existence of thief zones which uptake the injected water. Polymer gels have been successfully used to improve the sweep efficiency and to mitigate excess water production. However, due to the complexity of the reservoir, reservoir temperature, salinity, pH, lithology, and permeability, selection of proper gel system is still challenging. This paper aims to provide a literature review on six widely applied polymer gel systems used for conformance control applications. For this purpose, various databases, such as Google Scholar, One-petro and Scopus were extensively searched. Results of this study reveal that polymer gel systems can mainly be classified into two categories: conventional in situ-bulk gels and novel microgels. The first type is mainly for water shut off near the wellbore, where a polymer in-situ cross-linked with a metallic or organic agents. The second type of gels include preformed gel particles with various sizes and properties which provide permeability reduction deep in the reservoir. This study summarized the characteristics, developments and field application results of six widely applied systems. Comparison of these technologies based on their properties and performance under different reservoir conditions is also provided. Directions for further research and development of these gel systems especially for improving their application in higher temperature reservoirs, extreme fractures and deep permeability reduction are given.
Master of Applied Science
Civil and Environmental Engineering
Major Research Paper