Biogenic versus Thermogenic H2S Source Determination in Bakken Wells: Considerations for Biocide Application

详细信息    查看全文

• 作者：Jason Gaspar ; Drew Davis ; Carlos Camacho ; Pedro J. J. Alvarez
• 刊名：Environmental Science & Technology Letters
• 出版年：2016
• 出版时间：April 12, 2016
• 年：2016
• 卷：3
• 期：4
• 页码：127-132
• 全文大小：363K
• 年卷期：0

文摘

Hydrocarbon souring represents a significant safety and corrosion challenge to the oil and gas industry. H₂S may originate from geochemical or biogenic sources, although its source is rarely discerned. Biocides are sometimes utilized during well operations to prevent or inhibit H₂S generation. Here we develop a regional temperature map showing that downhole temperatures in Bakken reservoir wells equal or exceed the upper known temperature limit for microbial life. Attempts to extract microbial DNA from produced water yielded little to no detectable quantities. Stable isotope analysis yielded ^34Sδ values from 4.4 to 9.8‰, suggesting souring had a geochemical origin. Under Bakken reservoir conditions, anhydrite can react with hydrocarbons to form H₂S. Anhydrite present near the sour areas studied could be the underlying geochemical source creating this H₂S. In cases of geochemical souring, reevaluation of the need for biocide addition may provide significant reductions in both operational costs and overall environmental footprint.