A Review on Acid Gas Injection into Geological Formations with the Aim of Enhanced Oil Recovery and Environmental Protection: Theoretical Foundations

Nowadays, sulfur recovery processes tend to be no longer economic, as well as having various operational problems. They also discharge large amounts of CO2 into the atmosphere. The alternative is to compress and inject acid gas into geological formations with the purpose of enhanced oil recovery and acid gas sequestration for environmental protection. In this review article, after providing the initial definitions in acid gas studies, sour gas sweetening methods and their most prominent operational difficulties have been introduced and compared with each other by us. By completing the sour gas sweetening process, a problematic flow of acid gas is produced. Next, we address the theoretical foundations, the application scope, cost, and operational-economic challenges of different sulfur recovery methods in a try to explain the importance of exhausting the issue of acid gas injection in geological formations from a technical and economic point of view. We also present and discuss the principles of acid gas injection into geological formations, the criteria for selecting a suitable formation for injection, and the trapping mechanisms of acid gas.