More than 2,000 earthquakes of ML 2.0 and above have occurred in the Permian Basin region since 2017, including more than 10 above ML 4.5, making it the most seismically active basin in the midcontinent of the U.S. Research using this earthquake data has shown that seismicity occurs in three distinct geological systems in the region. Two of these systems are injection-inducted ruptures of basement-rooted faults in the northern Delaware Basin and the central Midland Basin associated with pore pressure increase from deep injection into strata above basement. The third system is within Permian-age shales and shallower strata in the southcentral Delaware Basin and is caused by rupture of strata-bound faults associated with a combination of shallow injection and hydraulic fracturing.

This talk will provide an overview of our current understanding of injection-induced seismicity in each of these systems, including detailed geologic characterization of injection strata and implications for injection capacity, modeling of pore pressure changes, and analysis of how the patterns and magnitudes of pore pressure change relate to fault rupture and induced seismicity. Regulatory and operator-led changes in injection practices and the impact on rates of seismicity will also be discussed. Finally, an assessment of the outlook for injection into each system given known dynamic injection capacity constraints will be provided.