OKLAHOMA SURPASSES CALIFORNIA IN EARTHQUAKES

Posted on May 1, 2015 by Mark Walker

Oklahoma has quietly earned the dubious distinction of earthquake capital of the Lower 48, having surpassed California last year.  In 2014, Oklahoma had 585 earthquakes of magnitude 3.0 or higher compared to California’s 180.  The cause of this dramatic rise in seismic activity, and whether it is induced by human activity, particularly by oil and gas operations, has been the subject of much discussion and scientific study.

When I last blogged about this subject (June 2014) the U.S. Geological Survey (USGS) and the Oklahoma Geological Survey (OGS) had just issued a joint warning of the increased risk of a M5.5 or greater earthquake in central Oklahoma, stating that the science suggests that a “likely contributing factor” to the increase in earthquakes is injection of oilfield wastewater into deep geologic formations.  Despite several sensational articles implying that industry has exercised undue influence over the OGS and its scientific conclusions, on April 21, 2015, the OGS issued a statement in which it reiterated the view that “the primary suspected source of triggered seismicity is…from the injection/disposal of water associated with oil and gas production…the OGS considers it very likely that the majority of recent earthquakes…are triggered by the injection of produced water in disposal wells . . . .”

On April 23, 2015, the USGS released a new report which again noted the connection between earthquakes and certain deep disposal wells, but concluded that, “induced seismicity does not occur near every disposal well, so it is important that we continue to study and learn more about how these earthquakes are generated…These changes may be related to oil and gas exploration activity but they also may depend on physical processes, which are poorly understood…many questions remain”.

As the science develops, the Oklahoma Corporation Commission (OCC), which regulates oil and gas wastewater disposal wells in Oklahoma under the SDWA Underground Injection Control program, has taken an aggressive approach.  The OCC has identified “areas of interest”, which are areas within 10 kilometers of any earthquake swarm.  Eight areas of interest encompassing approximately 112 square miles have been identified.  On March 12, 2015, the OCC sent letters to operators who dispose of oilfield wastewater into the deep Arbuckle formation within these areas of interest directing that they provide information from which it can be determined whether such disposal is in communication with the underlying crystalline basement rock.  If it is, the OCC is requiring that disposal into the Arbuckle be discontinued.  Failure to produce the information results in immediate curtailment of disposal by 50%.

With the downturn in crude oil prices, most companies have dramatically cut back on drilling and completing new wells.  This downturn itself may provide a scientific opportunity to see if reduced oilfield activity produces fewer earthquakes in Oklahoma.

Texas Railroad Commission on track to address quakes

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.

Another Disturbance In The Force: New Study Concludes That Co2 Injection In Texas May Have Caused Minor Earthquakes

Posted on November 15, 2013 by Dean Calland

New rumblings are being heard regarding carbon sequestration.  Proponents of the injection of substances into deep formations as a desirable method of waste disposal were shaken to learn that a study published just this week has concluded that the underground injection of carbon dioxide in Texas may have induced earthquakes.  This follows on the heels of a much publicized study performed for the Ohio Department of Natural Resources (ODNR) last year that concluded that the injection of oil field brine into an underground injection well (known as the Northstar 1 Well) near Youngstown, Ohio, was at fault for inducing seismic activity.  

The potential for causing earthquakes from CO2 injection has sent tremors through the clean coal (or perhaps “green coal”) camps.  Injection bans or significant regulatory hurdles that reduce the availability of injection could create severe aftershocks for the fossil fuel industry.  Affordable capture and underground storage of CO2 is a significant potential opportunity in the clean coal industry’s plan to extend the useful lives of coal burning industrial facilities.

Fortunately, both the Texas and Ohio studies suggest that the circumstances in which injection induces seismic activity are uncommon, although a number of citizen groups may not agree with this assessment.  Ohio’s experience with the underground injection of oil and gas waste fluids may predict how this will play out at the national level.  Beginning in March 2011, an area near the Northstar 1 Well experienced twelve minor earthquakes.  The State of Ohio began an evaluation, ordered the well and four nearby injection wells to cease operations, and discontinued issuing permits for new UIC wells.  ODNR concluded that injection in the Northstar 1 Well had indeed induced the earthquakes, but they resulted from injections into the “basement” Precambrian formation that had a pre-existing fault that was likely in a near-failure state at the time of the injections.   
          
The Texas study on CO2 published this week by the Proceedings of the National Academy of Sciences examined small earthquakes that occurred in 2009 through 2011 in a large oil and gas field in northwest Texas.  Operators in the area had been injecting CO2 to enhance oil recovery since 1971, and significantly increased injections in one of the fields, the Cogdell field, in 2004.  A temporary network of seismometers detected 93 earthquakes in the Cogdell field from March 2009 to December 2010.  However, no seismic activity was detected in nearby injection areas, causing the authors of the study to conclude that seismic activity is likely to occur only in areas with geological faults that are unstable at the time of injection.  Thus, there is not much of a gap between the findings of the Texas and Ohio studies. 

This issue is likely to create an even wider fissure between clean coal supporters and environmental groups, although future studies will likely determine if this debate grows to seismic proportions.