Environmental challenges in fracturing of unconventional resources

Abstract

With support of the SEG Research Committee, the authors of this paper organized a special session at the 2011 SEG Annual Meeting focused on the environmental challenges of developing tight, unconventional hydrocarbon reservoirs with special emphasis on the controversial hydraulic fracturing technology. Goals of the session were to support a better understanding of the challenges from the environmental perspective and to discuss possible solutions to these challenges through improving existing methods and developing novel exploration and stimulation techniques. Recognized unconventional resource experts brought their perspectives to the special session to highlight these challenges and work toward bringing the community together for solutions. It is evident that advances in horizontal drilling and multistage fracturing technologies have had significant influence on the global spread of the exploration for and production from gas shale and shale oil reservoirs.

Groundwater Protection and Unconventional Gas Extraction: The Critical Need for Field‐Based Hydrogeological Research

“…The increasingly long horizontal wells (most laterals are more than 1 km or more than 3000 ft) with an increasing number of fracturing stages (Tutuncu et al 2012) used in unconventional gas production require substantially higher hydraulic fracturing-fluid injection volumes, however. For example, water-based hydraulic fracturing of the Horn River Basin (British Columbia, Canada) requires approximately 50,000 m 3 of fluid (10-20 million gallons) and approximately 2000 metric tons of proppant per horizontal well with 20 fracs per well (Johnson and Johnson 2012).…”

“…However, a Society of Exploration Geophysicists research committee has reported that "downhole microseismic monitoring has limited spatial coverage creating a bias at the event locations and an incomplete view of the stimulated reservoir volume" (Tutuncu et al 2012). Reducing this bias would require one or more shallow (30 to 60 m deep) boreholes drilled exclusively for seismic monitoring (which, notably, could be used for subsequent groundwater monitoring).…”

“…Over the past few years numerous editorials, reports, and issue papers have been written about environmental issues related to shale gas development, all of which address groundwater issues to varying extents (e.g., Kargbo et al 2010;Zoback et al 2010;Schnoor 2012;ALL Consulting 2012;Groat and Grimshaw 2012;Rozell and Reaven 2012;Tutuncu et al 2012; UK Royal Society/Royal Academy of Engineering 2012). Many of these contributions are "white papers," focusing mainly on delineating the potential environmental issues, probable causes, and possible solutions (largely associated with more rigorous regulation and improved industry practices).…”