Posted on August 28, 2014 by Jeff Civins
Over 30 earthquakes jolted the area in and around the City of Azle, Texas —20 miles north of Fort Worth—last November through January. In response to citizen concerns, the Texas House Committee on Energy Resources created a Subcommittee on Seismic Activity, to investigate whether there was a link between earthquakes and increased oil and gas production and disposal wells. In addition, the Railroad Commission of Texas—the agency with jurisdiction over oil and gas activities in Texas–hired a state seismologist and, on August 12, approved a draft of proposed rules that would require companies to do a seismic survey before obtaining permits for new oil and gas disposal wells—so-called Class II injection wells. Representatives of both the Texas oil and gas industry and environmental groups are supportive of this proposal.
Texas, in particular, has been part of the tremendous increase in oil and gas exploration and production activity nationwide through hydraulic fracturing and horizontal drilling. Although “fracking” per se does not appear to result in quakes, there is a concern that related disposal well injection might. The Railroad Commission proposal is intended to address this concern. Some have suggested the Texas proposal could be a model for other states.
The proposal would require applicants for oil and gas injection wells used for disposal to provide additional information, including logs, geologic cross-sections, and structure maps for injection well in an area where conditions exist that may increase the risk that fluids will not be confined to the injection interval. Those conditions include, among other things, complex geology, proximity of the base rock to the injection interval, transmissive faults, and a history of seismic events in the area as demonstrated by information available from the USGS. The proposal also would clarify that the Commission may modify, suspend, or terminate a permit if fluids are not confined to the injection interval, that is, if it poses a risk of seismic activity. Presumably, the effect of the proposal, if promulgated, will be not only to regulate oil and gas disposal activities to address potential seismic effects, but also to generate data that may be useful in determining whether and to what extent further regulation is needed.