Multidisciplinary Approach to Identify and Mitigate the Hazard from Induced Seismicity in Oklahoma

Abstract:

Oklahoma has experienced a very significant increase in seismicity rates over the last 5 years with the greatest increase occurring in 2014. The observed rate increase indicates that the seismic hazard for at least some parts of Oklahoma has increased significantly. Many seismologists consider the large number of salt-water disposal wells operating in Oklahoma as the largest contributing factor to this increase. However, unlike many cases of seismicity induced by injection, the greatest increase is occurring over a very large area, about 15% of the state. There are more than 3,000 disposal wells currently operating within Oklahoma along with injection volumes greater than 2010 rates. These factors add many significant challenges to identifying potential cases of induced seismicity and understanding the contributing factors well enough to mitigate such occurrences. In response to a clear need for a better geotechnical understanding of what is occurring in Oklahoma, a multi-year multidisciplinary study some of the most active areas has begun at the University of Oklahoma. This study includes additional seismic monitoring, better geological and geophysical characterization of the subsurface, hydrological and reservoir modeling, and geomechanical studies to better understand the rise in seismicity rates. The Oklahoma Corporation Commission has added new rules regarding reporting and monitoring of salt-water disposal wells, and continue to work with the Oklahoma Geological Survey and other researchers.