THE EVOLVING SPATIO-TEMPORAL ASSOCIATION BETWEEN EARTHQUAKES AND WASTEWATER INJECTION WELLS IN OKLAHOMA

The Oklahoma Geological Survey (OGS) monitors seismicity throughout the state utilizing permanent and temporary seismometers installed by OGS and other agencies, while maintaining an earthquake catalog. The catalog is complete down to M2.4 since mid-2014, despite the significant workload for a solely state-funded regional network including 624 M3.0+ earthquakes in 2016 and 285 M3.0+ in 2017 (at the time of this submission). We test the spatial limits of earthquake association to individual wells and investigate whether those limits have evolved over the last decade. We also evaluate these relationships in light of the Oklahoma Corporation Commission announcing broader restrictions on wastewater injection wells completed into the Arbuckle in the area of Oklahoma experiencing seismicity, with limits of 10,000 bbl/day in the north-central portion of the state and 15,000 bbl/day in western Oklahoma. The potential findings and future actions guided by these types of studies highlight the continued need for an expansion and densification of seismic monitoring throughout Oklahoma.