Bacterial contamination of fracturing fluids leads to a number of serious
problems in the oil field. If the fracturing fluids are poorly treated or untreated,
sulfate-reducing bacteria (SRB) and acid-producing bacteria (APB) can become
established downhole, in production lines, gas / fluid separation, storage equipment,
and in the gas gathering and transportation systems. This may result in hydrogen
sulfide production, iron sulfide production and microbially influenced corrosion (MIC).
Many of these fracturing fluids contain polyacrylamide or sugar-based polymers and
other organic compounds which serve as food sources for bacteria. As a
consequence of the water volume required for the fracturing process, the water used
for preparation of these fluids is obtained from rivers, lakes, or oil field wastewater
and is heavily contaminated with bacteria. This paper presents a case history
discussing the background survey of various fracturing water sources, the biocide
selection process, bacterial mitigation program implementation, monitoring and
optimization of a Barnett Shale fracturing biocide program.