Preliminary analysis of seismicity near Eagleton 1-29, Carter County, July 2014

Abstract

On July 8th, we, The Oklahoma Geologic Survey (OGS) were notified by the Oklahoma Corporation Commission (OCC) that they had received an email indicating possible seismic activity associated with the hydraulic fracturing of the Eagleton 1-29 well located in Section 29 5S 2W in southern Carter County, Oklahoma. While this area of Oklahoma has a low level of background of seismicity, about 10 located events per year, there have been 43 earthquakes located in the area for 2014 (Figure 1). We were aware of an increase in earthquakes occurring in this area however, we were not aware of the hydraulic fracturing of Eagleton 1-29. Of the recent events, 26 coincide, in time and space, with the hydraulic fracturing of Eagleton 1-29, July 7th through July 9th, 2014, UTC. The OCC provided us with the pumping curves for the stimulation of the Eagleton 1-29. In this study, we will address the seismicity coincident with the hydraulic fracturing of Eagleton 1-29 as the Wilson 2014 sequence, centered 6 miles southwest of Wilson, Oklahoma. The study area includes the area between latitudes 33.95N and 34.20N and longitudes 97.6W and 97.25W. Also, included in this report is the derivation of the local magnitude scale used by the OGS in Appendix A. This report will document the background seismicity and the recent swarm, Wilson 2014, coinciding with the hydraulic fracturing of Eagleton 1-29 well. This area has been and may continue to be seismically active this analysis should be considered preliminary and with ongoing seismicity and research our understanding of this seismicity could change.