Acid Gas Injection into Geological Formations with the Aim of Enhanced Oil Recovery and Environmental Protection: A Review of Formation Damage Mechanisms, Areas and Principles of Experimental Research

With the discovery of sizeable sour gas fields in recent years and the reduction of sulfur prices, the economic unattractiveness has been added to the operational and environmental problems of sulfur recovery methods. The alternative solution to deal with the troublous acid gas flow resulting from sour gas sweetening is the acid gas injection into geological formations. It protects the environment from toxic and greenhouse gases and creates new opportunities for enhanced oil and gas recovery. This method’s economic attractiveness and the ever-increasing strictness of environmental laws have increased research interest in acid gas sequestration and EOR studies in recent years. There was no thorough literature review to be used as a comprehensive and rapid guide by researchers interested in acid gas studies. This review article tries to clarify the challenges and requirements that researchers may face in selecting the appropriate study technique and experimental apparatus design in acid gas studies. After reviewing reservoir rock and fluid interactions with acid gas and possible formation damage mechanisms, the importance of core-flood experiments for simulating the multi-phase flow inside geological formations in acid gas injection projects shall be explained. We will present the research areas explorable with such experiments and evaluate, compare, and analyze the several experimental techniques and prominent experimental apparatuses available in the literature used to understand the multi-phase flow and monitor the internal rock and fluid system during acid gas injection. Finally, specific safety considerations for acid gas study laboratories will be provided.