Following a 5.4 magnitude earthquake on November 16 in Reeves County, the Railroad Commission of Texas is implementing several revisions to the seismicity reduction response plan in the Northern Culberson-Reeves Seismic Response Area (SRA).
The SRA was created to address the intensity and frequency of earthquakes in the area and reduce the occurrence of high-magnitude seismicity such that recurrence of 3.5 magnitude events is decreasing by December 31st, 2023.
The response plan sets curtailments on the injection volumes of produced water (which is water produced during oil and gas production) into disposal wells. The scope of the plan is being revised following reviews of seismicity data and injection volumes.
The SRA boundary is being expanded northward to the New Mexico border, which will increase the size of the SRA from 2,366 square miles to 2,601 square miles. There are 78 active disposal wells in the revised SRA.
The target for reducing daily injection volumes in deep disposal wells is being reduced even further. Operators of deep disposal wells in the Revised Response Plan have agreed to reduce the collective volume of disposal from the original target of 298,000 barrels per day by June 30, 2023 to 162,000 barrels per day by that date. This would be about a 68% drop in disposal volume compared to January 2022 before the plan went into effect.
More changes are on the way. RRC staff continue to study revisions to the shallow disposal well injection volume schedules in the SRA and will be looking at changes along with possible new data collection efforts.
The potential lag time between changes in injection rates and changes in seismicity varies; historical activity indicates a potential lag time of 12-18 months.
As part of the recent revisions, the RRC will also promote expanded data collection to support seismicity research to inform policymakers on future data needs for effective regulation to protect residents and the environment. The data collection will include a voluntary survey of available historical and current reservoir pressure, encouraging the use and reporting of continuous down-hole pressure monitoring data and assessing the origins of disposal volumes — whether from in-state or out-of-state sources.
The Revised Response Plan and other documents can be found by scrolling to the Northern-Culberson Reeves section of the RRC Seismicity Response webpage.