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Methane emissions

Emissions of naturally produced methane gas may occur following hydraulic fracturing and well completion during the "flowback" of the well when some methane, hydraulic fracturing fluids (primarily water) and formation water return to the surface immediately prior to the well being put into production. Industry takes safeguards to minimize these emissions.

Economically viable and officially recognized technologies now exist, which can capture the methane that would otherwise escape into the atmosphere. The captured gas may be sold or combusted, resulting in significant environmental and potential economic benefits. The application of technologies to reduce air emissions has been made compulsory in the U.S. from 2015 onwards. Starting 15 October 2012, all gas emissions from flowback operations must be captured and combusted. From 2015 onwards, all gas capable of entering the transmission line must be routed to sales.

According to a study by the University of Texas, methane emissions from natural gas production are 0.42 per cent of produced natural gas, similar to the most recent estimates of the U.S. Environmental Protection Agency (EPA). The authors found that at the majority of hydraulically fractured well completions sampled, industry has proactively imposed green completion technology which effectively reduced methane emissions by 99 per cent. As a result, methane emissions from well completions are 97 per cent lower than 2011 national emission estimates published by EPA in April 2013.

New Technologies

Flowback water from the hydraulic fracturing process may contain high concentrations of methane, some of which is flared at the well-site. Reduced Emission Completion (REC) technologies, also known as "green completions", filter and capture this methane so that releases into the atmosphere are minimized. The process requires that gas emitted from flowback emissions must be sent to a pipeline as soon as it meets pipeline specifications. If a pipeline is not built to the well site, the well must be shut once it is capable of flowing into a sales line. During the time the well cannot flow into a pipeline, the gas must be combusted.

The use of REC technology in European shale gas wells would be made all the more commercially interesting because the value of the gas captured is higher. Moreover, proper planning, favored by the existing European licensing framework, allows for a timely coordination of drilling and pipeline installation. Industry is working with suppliers to ensure that the availability of REC equipment keeps up with demand.