New-Generation Microbial Testing Compares Favorably With Traditional Technologies in Identification of Bacterial Contamination of Oil and Gas Systems

摘要

Ever-increasing demands are being placed on oil and gas production operations to become more efficient, cost-effective, and environmentally compliant. Greater emphasis is now being placed on the use of monitoring tools to measure system performance. Consequently, monitoring and controlling microbiological contamination in upstream oil and gas processes and facilities are common practice. Uncontrolled microbiological growth and activity can create severe operational, environmental, and safety issues, resulting from microbially induced influenced corrosion (MIC), solids production, and hydrogen sulfide (H2S) generation. In addition, bacteria can degrade drilling and well stimulation fluids and enter the producing formation, and subsequently the surface production equipment and tanks, during the initial drilling, stimulation, and completion of a well. These problems can be managed by understanding where microorganisms exist in the systems, the quantity of microorganisms present, and the relative activity of the microbial populations. In short, the ability to more proactively and comprehensively monitor microorganisms gives an enhanced ability to control their proliferation and thus reduce their impact.There are several microbiological monitoring tools in common use today, ranging from direct microscopic examination to culture-based counting techniques. Other industries have benefited from the use of various cutting-edge molecular monitoring tools, such as the Adenosine Triphosphate (ATP) measurement technique. Traditionally, the measurement of ATP in oilfield operations has been problematic due to various assay interferences prevalent in oilfield samples, including oil, suspended solids, and dissolved solids. The continued interest in the ATP assay, due to the rapid acquisition of results, has led to a new generation of methodology suitable for use in oilfield samples.This paper summarizes results obtained from testing various surface, seawater, and produced water samples from oil and gas systems throughout North America. Microbiological characteristics of each sample were qualified and quantified using traditional techniques, microscopic examination, and culture testing, and then compared to the new-generation ATP analysis results. A high-level comparison of these methodologies is presented, and subsets of the data are presented for in-depth examination in a series of case studies. It was found that the 2Td Generation ATP test used in these studies compared favorably with findings from traditional microbial measurement tools, including epifluorescence microscopy and serial dilution-to-extinction culture tests, while providing the benefits of field readiness and immediate feedback.