SULFIDE REMOVAL AND PREVENTION IN GAS-WELLS

Major problems in oil and gas operations result from the biogenic form ation of H2S in the reservoir. The presence of H2S results in increase d corrosion, iron sulfide formation, higher operating costs, reduced r evenue, and constitutes a serious environmental and health hazard. A n ew technology that removes and prevents the formation of biogenic H2S has been developed. The technology is based on the addition of low con centrations of a water-soluble nutrient solution, which selectively st imulates the growth of an indigenous microbial population, thereby inh ibiting the detrimental sulfate-reducing bacteria (SRB) population, wh ich causes the generation of H2S. This deliberate and controlled modif ication of the microflora and reservoir ecology has been termed biocom petitive exclusion. This directed alteration of the microbial ecology is achieved by the introduction of a nutrient formulation that favorab ly influences the dynamics of the reservoir microflora. The treatment system does not require the addition of microbial cultures. Periodic w ell treatments have been shown to dramatically reduce or completely el iminate 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 eff ectiveness of this new approach to treating and remediating wells with high levels of H2S. The versatility and low cost of this novel techno logy offers the petroleum industry a practical and cost effective meth odology for the control of H2S in oil and gas wells.