Advancements in H2S Scavenger Technology

Abstract

Presence of H2S in oilfield systems adds to many operational difficulties such as safety, compliance, environmental, and corrosion. Treatment and handling of sour production greatly increases overall well operational costs. Triazine based chemistries are often applied to eliminate H2S from the system. Three major applications where H2S scavengers are applied are produced gas, mixed production, and separated oil. Use of triazine to treat H2S has many drawbacks such as the formation of insoluble solids, which has resulted in the shutdown of gas contact towers. Triazine often exhibit low efficiency and kinetics in mixed production applications and have caused scaling by considerably raising the brine pH. Triazines are normally successful in removing H2S from oil, however large concentrations of these aqueous-based scavengers can have a considerable impact on BS&W, potentially resulting in out-of-spec oil. Triazines that partition into desalted oil can also cause downstream corrosion problems in refineries by producing corrosive hydrochloride salts in crude towers. As a result, several refineries have downgraded or banned crude containing triazines. This paper describes recent development to create new scavenger technologies that helps enable efficient scavenging while eliminating or greatly decreasing issues associated with present scavenger technology. Rather than a universal H2S scavenger with potential performance sacrifices, the strategy followed was to build scavengers that were a best fit for each application. Understanding the application environment and selecting the best scavenger chemistry for the job can result in considerable CAPEX and OPEX savings, increased productivity, improved dependability, and safer H2S management.