Methods of combating biogenic hydrogen sulfur at the Uzen and Karamandibas oilfield

In order to study and control microbiological contamination with sulfate-reducing bacteria of oilfield fluids we have monitored the performance of bactericidal reagents at the Uzen field. Water samples were taken at the equipped control points for the content of SRB cells before and after the injection of the bactericide. Due to the increase in the content of hydrogen sulfide in November December 2020 at the fields of Ozenmunaygas JSC, a technical inspection of the NSM-4 facility and the reagent injection unit was carried out by KazNIPImunaygas together with specialists from the structural divisions of the Department for Oil Treatment and Production Services of OMG and the Office on chemistry and OMG. Further, KazNIPI performed laboratory tests to determine the miscibility of the bactericide with seawater at different temperatures. Based on the results of the studies performed, following recommendations were developed: seawater tank biocide treatment recommendation, biocide injection system and injection point improvement in order to ensure proper mixing of the biocide with seawater. We also recommended to perform field trial of new biocides in order to avoid the development of bactericide resistance in the bacteria.