Comparison of Water-Based Fluid Field Bacteria Detection Methods Used in Oil and Gas (C2026-00175)

Danniela Gutierrez, Anna Confer, Keith mcLeroy

In the oil and gas industry, the growth of bacteria plays a significant role in metal corrosion and reservoir souring, posing substantial risks to oil and gas assets. To mitigate these impacts, timely and accurate bacterial detection is critical for effective bacterial management. As bacteria populations can change over time after sample collection, samples should be analyzed within 24 hours to ensure accurate bacteria counts. This study evaluates three field-based methods traditionally used in the oilfield for bacteria quantification which include – 1) an enzyme-based assay which detects metabolic activity, 2) an adenosine triphosphate (ATP)-based assay which measures microbial ATP, and 3) a serum serial dilution test (SSDT) colorimetric culture method. The study conducted a side-by-side comparison of field samples collected from typical oilfield sources including produced water, injection/disposal waters, seawater, as well as surface “pond” water typically used for fracking operations. Water samples were selected to ensure diverse bacterial communities were fully evaluated using these testing techniques. This study reports on how the three different bacterial testing methods compare, including their responses to kill studies with typical oilfield biocides, highlighting the strengths and limitations of each, and providing some guidance on the suitability of each method for each application.