We have investigated seismicity potentially associated with hydraulic fracturing (HF) in several areas of the Central and Eastern United States to improve our understanding of the phenomena. In our study we utilized multi-station template matching to lower the detection threshold and improve the completeness of seismicity catalogs. We also collected all publicly available information on timing and location of HF-related well stimulations to evaluate relationships with recorded seismicity. While rare, we find that HF induces seismicity with magnitudes greater than 2.0 more often than generally assumed and is the dominant source of seismicity in some areas. In over a dozen regions, >90% of the seismicity was correlated with reported HF wells, and in a few cases >30% of the HF wells were correlated with seismicity. Across the states of Ohio, Oklahoma, and Texas, we have identified ~600 earthquakes with M 2.0-3.8 that are best explained by being induced by HF. These findings imply regulations that require operators to modify completion strategies if a M > 2.0 earthquake occurs are likely to have an impact on future operations. Detailed investigations of seismicity induced by HF indicate that the maturity of nearby faults plays a key role in the types of seismicity that are produced. In addition, we find several lines of evidence that poroelastic stress changes from HF contribute to the production of observed seismicity.
AAPG Datapages/Search and Discovery Article #90350 © 2019 AAPG Annual Convention and Exhibition, San Antonio, Texas, May 19-22, 2019