Microbiological assessment of reservoir souring in oil fields of Siri Island, Persian Gulf, during water injection

Abstract

This study investigates the source of hydrogen sulfide gas in the oil fields of Siri Island, Persian Gulf Basin, through microbiological and geochemical analyses of output, seawater input, and injection water samples. The findings suggest that reservoir souring is primarily caused by bacterial sulfate reduction, likely triggered by enhanced recovery methods such as water injection. Microbiological tests identified sulfate-reducing bacteria, with Desulfovibrio species being the dominant type, accounting for 81% of the bacteria identified. These bacteria were responsible for hydrogen consumption in the oil reservoir, leading to hydrogen sulfide production. The research concludes that Desulfovibrio bacteria play a critical role in souring processes in Siri Island oil fields. This study provides key insights into microbial mechanisms of reservoir souring, offering valuable information for improving oil recovery strategies and mitigating souring in future operations.