Protocols for Investigating the Microbiology of Drilling Fluids, Hydraulic Fracturing Fluids, and Formations in Unconventional Natural Gas Reservoirs

Abstract

Microorganisms that are present in drilling fluids, hydraulic fracturing fluids, and natural gas reservoirs cause a number of problems (e.g., souring of natural gas, corrosion of field infrastructure) that lead to significant costs for the natural gas industry. In spite of their importance, relatively little is known about the abundance, diversity, and community structure of the microbial guilds in (1) fluids that are used to construct natural gas wells or (2) natural gas reservoirs prior to well construction. This chapter provides protocols that can be used to study the microbiology of drilling fluids, hydraulic fracturing fluids, and natural gas reservoirs. The chapter also includes procedures for (1) the timely collection, preservation, transport, and handling of samples from relevant locations; (2) the enumeration of microorganisms that have been implicated in deleterious processes that occur within natural gas wells; (3) the use of cultivation-independent, nucleic acids-based approaches for the characterization and quantification of microorganisms in samples from natural gas wells; and (4) handling and interpreting nucleic acid sequence data in samples from natural gas wells. Relevant information regarding suppliers of equipment, troubleshooting techniques that can be used to overcome problems that may be encountered while studying the microbiological properties of natural gas wells, and research questions that need to be addressed in future studies are also discussed.