Microbial H2S generation in hydrocarbon reservoirs: Analysis of mechanisms and recent remediation technologies

Abstract

Sulphate reducing prokaryotes (SRP) cause hydrogen sulphide (H₂S) generation in some waterflooded hydrocarbon reservoirs that is known as microbial reservoir souring or biosouring. The H₂S generated in-situ by SRP is toxic and corrosive that adversely affects the quality, production, and economy of oil fields together with negative environmental impacts. Various chemical, biological, and microbial methods have been implemented to control such in-situ microbial reactions in the past few decades but still they are not fully controllable. This work aims to give deeper insight into microbial reservoir souring and its mitigations techniques. First, this review elaborates on the complex physics of souring and subsequently explores the latest modelling tools being used to capture the biochemistry of souring and the physics of H₂S generation. Later, a critical discussion on the impact of governing parameters such as fluid composition, temperature, pressure, pH, and salinity on H₂S biogeneration is added. Next, H₂S-fluid-rock interactions leading to partitioning, adsorption, and scavenging phenomena are scientifically explained and their effects on H₂S transport are elucidated. Various mitigation and control techniques are presented and critically compared in view of their suitability and applicability in different scenarios. Finally, some field cases are reported, and the key challenges and the forthcoming research requirements are highlighted. This insightful review provides necessary information on microbial activities in hydrocarbon fields that are important for chemical and petroleum engineers to tackle souring issue.