Two-year survey comparing earthquake activity and injection-well locations in the Barnett Shale, Texas

Abstract

, temporary seismographs deployed under the EarthScope USArray program were situated on a 70-km grid covering the Barnett Shale in Texas, recording data that allowed sensing and locating regional earthquakes with magnitudes 1.5 and larger. I analyzed these data and located 67 earthquakes, more than eight times as many as reported by the National Earthquake Information Center. All 24 of the most reliably located epicenters occurred in eight groups within 3.2 km of one or more injection wells. These included wells near Dallas-Fort Worth and Cleburne, Texas, where earthquakes near injection wells were reported by the media in 2008 and 2009, as well as wells in six other locations, including several where no earthquakes have been reported previously. This suggests injection-triggered earthquakes are more common than is generally recognized. All the wells nearest to the earthquake groups reported maximum monthly injection rates exceeding 150,000 barrels of water per month (24,000 m 3 ∕mo) since October 2006. However, while 9 of 27 such wells in Johnson County were near earthquakes, elsewhere no earthquakes occurred near wells with similar injection rates. A plausible hypothesis to explain these observations is that injection only triggers earthquakes if injected fluids reach and relieve friction on a suitably oriented, nearby fault that is experiencing regional tectonic stress. Testing this hypothesis would require identifying geographic regions where there is interpreted subsurface structure information available to determine whether there are faults near seismically active and seismically quiescent injection wells.induced earthquakes | triggered earthquakes | unconventional gas development | seismic hazards | domestic energy policy

Analysis of the Cleburne, Texas, Earthquake Sequence from June 2009 to June 2010

“…In the case of the nearby earthquakes at DFW airport, a plausible linkage was found between the disposal of the wastewater and the subsequent earthquakes in the region (Frohlich et al, 2011). A more comprehensive study of local seismicity throughout the Fort Worth basin (Frohlich, 2012) using USArray data to detect and locate events across the basin concludes that there may be a number of locations where small earthquakes are occurring near wastewater injectors. As a result of these previous calculated from source spectra and Lg magnitudes, as calibrated from USGS reports and the pseudomagnitude scale in Figure 6.…”

“…Previous investigations of recent seismicity in the Fort Worth basin have identified numerous small earthquakes occurring in close association with injection wells. The survey in Frohlich (2012) of 67 small earthquakes in the Fort Worth basin from 2009 to 2012 found that all the most reliably located events occurred in eight groups each situated within 3.2 km of active injection wells. During the study period, other seismic events ( Fig.…”

A review of physical supply and EROI of fossil fuels in China

“…The potential constraints from environmental issues are not included. Taking shale gas as an example, extracting shale gas may result in many environmental problems, including methane emissions, water use, water pollution, and induced earthquakes (Howarth and Ingraffea 2011;Entrekin et al 2011;Frohlich 2012). Among these, water issues may be the most significant constraining factor for China shale's gas development.…”

Modeling of the in situ state of stress in elastic layered rock subject to stress and strain-driven tectonic forces

“…It is also key for the civil engineering, mining, and energy industries, covering topics as diverse as hydraulic fracturing, rock stability, and fluid circulation (Simonson et al, 1978;Van Eekelen, 1982;Warpinski et al, 1985;Hopkins, 1997;King, 2010;Fisher and Warpinski, 2011;Davies et al, 2012). Furthermore, it is important for determining the likelihood of felt seismicity due to human activities, for instance, because of hydraulic fracturing or saltwater disposal (Frohlich, 2012;Ellsworth, 2013;Weingarten et al, 2015;Atkinson et al, 2016).…”