18-25. Revitalization of hydraulically fractured shale oil and gas wells through enhanced microbial natural gas production

Large increases in oil and natural gas production in the U.S. have been driven by unconventional technologies (directional drilling and hydraulic fracturing) in shale. With this technology there is a finite reserve of oil or gas that is available and once it has been recovered (sometimes after several rounds of hydraulic fracturing and enhanced oil recovery stimulations) the well is capped. It may be possible to extend the life of existing wells and associated infrastructure by promoting microbial gas production in existing shale wells. Microbially-produced (biogenic) natural gas is of interest because there is potential for regenerating biogenic gas by stimulating biodegradation of carbon sources in-situ. Microbial methane production (microbial methanogenesis) is relatively slow under natural conditions and would not be commercially viable; however, it may be possible to develop a methodology that would stimulate microbial methanogenesis in situ to produce economic quantities of biogenic gas within a reasonable time frame (months to years). Development of a viable methodology for the stimulation of microbial methanogenesis in shale would provide additional natural gas resources using existing infrastructure. In theory, many cycles of stimulation and production are possible if biodegradable organic matter remains accessible in the shale to microbes. 

A current project within the USGS Energy Resources Program is examining the stimulation of microbial methanogenesis in coal. This project has had major success in understanding the biogeochemical pathway leading from coal geopolymers to methane gas, and the major microbial groups involved along the biodegradation pathway. The project has also developed a methodology for stimulating microbial methanogenesis in situ in coal beds. The methodology has been tested in laboratory bottles and upscaled experiments, and a partial field test of the methodology at a USGS test site in the Powder River Basin coal field in eastern Montana was successful in stimulating methane production. While shale differs in many respects from coal, it is anticipated that many of the major biogeochemical pathways and microorganisms involved in the process will be similar in both environments. Also, based on our work in coal we have developed a template for how to conduct studies of stimulation of microbial methanogenesis in fossil energy deposits.

We seek a Mendenhall Postdoctoral Scholar with a background in bioengineering and an understanding of microbiology, biogeochemistry, and related disciplines to conduct research on biogasification (microbial methanogenesis) of organic-rich shale. The postdoctoral researcher will conduct both laboratory and field investigations designed to provide insights on the detailed steps in the anaerobic biodegradation of coal from geopolymers to simple molecules utilized by methane-producing Archaea.   

We encourage innovative research proposals designed to address the following areas focused on understanding the potential of biogasification in shale. Integration and synthesis of datasets, along with novel approaches to enhance or better understand biogasification in shale are also encouraged.  

An evaluation of shale reservoirs producing biogenic methane.  An analysis of biogenic natural gas production literature will be conducted to determine what shale reservoirs produce biogenic natural gas, the characteristics of those reservoirs (shale and formation water chemistry, temperature, etc.), and the types of microorganisms that are present that have been identified in literature. The purpose is to determine the environmental conditions and microbial populations most favorable to methane production in shale. This work will complement an assessment of biogenic gas production (Shelton and others) being conducted by the USGS Energy Resources Program. 

Studies of microbial methanogenesis of shale. The purpose of the proposed field and laboratory studies is to establish the levels of biogenic methane production under background conditions of unstimulated shale gas production (both oil and gas producing). Laboratory experiments will examine approaches for stimulating microbial gas production, including nutrient and substrate addition, substrate for stimulating microbial biomass, and physical/chemical changes to shale (e.g. oxidation) that may enhance bioavailability. These experiments will result in a methodology for enhancing microbial methanogenesis in shale that is both practical and capable of producing economic quantities of natural gas in a reasonable time frame (months to years). Previous studies of enhanced biogenic methane production in coal beds provide a basic template of how to conduct studies of enhanced microbial methanogenesis. This includes field studies of environmental conditions where biogenic methane is produced, and lab studies involving bottle experiments that can be manipulated to maximize methane production. However, it is likely that enhancing biogenic gas production in shale will involve many different problems compared to previous coal methanogenesis studies. For example, there are big differences between organic matter type, hydrogeochemistry, and permeability in shale and coal that will need to be addressed for enhanced gas production in shale. 

Develop preliminary methodology. Based on the results of field and laboratory experiments, a preliminary methodology will be developed for stimulation of microbial methanogenesis in hydraulically fractured shales. 

Interested applicants are strongly encouraged to contact the Research Advisor(s) early in the application process to discuss project ideas.

Proposed Duty Station: Reston, VA or Helena, MT 

Areas of Ph.D.: Microbiology, bioengineering, biogeochemistry, or molecular biology with a focus on biodegradation processes; or related fields (candidates holding a Ph.D. in other disciplines, but with extensive knowledge and skills relevant to the Research Opportunity may be considered).

Qualifications: Applicants must meet the qualifications for: Research Biologist, Research Chemist 

(This type of research is performed by those who have backgrounds for the occupations stated above. However, other titles may be applicable depending on the applicant's background, education, and research proposal. The final classification of the position will be made by the Human Resources specialist.)

Human Resources Office Contact: Audrey Tsujita, 916-278-9395, atsujita@usgs.gov