Responding to numerous citizen complaints about increased seismic activity thought to be linked to oil and gas drilling wastewater injection wells, Railroad Commission of Texas (RRC) staff has proposed rule changes to strengthen commission enforcement of disposal wells.
"While few earthquakes have been documented over the past several decades relative to the large number of disposal wells in operation, seismic events have infrequently occurred in areas where there is coincident oil and gas activity," RRC staff said in its memorandum to commissioners.
In January about two-dozen residents in and around the Barnett Shale region town of Azle, TX, appealed to the RRC to do something about the tremors, which they said were destroying property values and their quality of life (see Shale Daily, Jan. 21).
Among the recommendations is for the RRC to require "additional permit application information such as logs, geologic cross-sections and/or structure maps for an injection well in an area where conditions exist that may increase the risk that fluids will not be confined to an injection interval."
The proposed amendments to existing rules also seek to clarify that the RRC has the authority to shut down an injection well if fluids are not confined to the intended injection interval.
Further, applicants for new disposal well permits would be required to include a review of U.S. Geological Survey (USGS) data "regarding the location of any historical seismic data" in the vicinity of the planned well.
"The USGS has the ability to detect and locate all seismic events larger than magnitude 2.0 throughout the continental United States," RRC staff said. "This ability makes the USGS the de facto source of seismic event location in the United States."
The RRC recently released some company data on injection wells to the public so that researchers studying the increased seismic activity can consider whether there is a relationship to injection well activity (see Shale Daily, June 18). The Texas House of Representatives also has formed a special committee to hear citizen and industry concerns (see Shale Daily, May 13).
The proposed rule changes are to be published in the Texas Register on Aug. 29 with a 30-day comment period to follow.