Sulfide Removal and Prevention in Gas Wells

Abstract

Summary Major problems in oil and gas operations result from the biogenic formation of H2S in the reservoir. The presence of H2S results in increased corrosion, iron sulfide formation, higher operating costs, reduced revenue, and constitutes a serious environmental and health hazard. A new technology that removes and prevents the formation of biogenic H2S has been developed. The technology is based on the addition of low concentrations of a water-soluble nutrient solution, which selectively stimulates the growth of an indigenous microbial population, thereby inhibiting the detrimental sulfate-reducing bacteria (SRB) population, which causes the generation of H2S. This deliberate and controlled modification of the microflora and reservoir ecology has been termed biocompetitive exclusion. This directed alteration of the microbial ecology is achieved by the introduction of a nutrient formulation that favorably influences the dynamics of the reservoir microflora. The treatment system does not require the addition of microbial cultures. Periodic well treatments have been shown to dramatically reduce or completely eliminate sulfide levels and establish control of the system in diverse field demonstrations supported by the U.S. Dept. of Energy. Field data in a variety of reservoirs will be presented that demonstrate the effectiveness of this new approach to treating and remediating wells with high levels of H2S. The versatility and low cost of this novel technology offers the petroleum industry a practical and cost effective methodology for the control of H2S in oil and gas wells.