Combining InSAR and Comprehensive Subsurface Data to Understand Regional Anthropogenic Uplift, Subsidence, Faulting and Earthquakes in the Delaware Basin, West Texas

Thirteen years of horizontal drilling into shale strata has turned the Delaware Basin of west Texas and southeast New Mexico into one of Earth's most prolific oil fields, producing 5.7 million barrels of oil per day in 2022. Oilfield wastewater is also produced necessitating disposal by injection. Total injection from 2010-2021 is 133 billion barrels into strata both above (82%) and below (18%) the shale layers targeted for drilling. The maximum injection rate has been ~8.5 million barrels/day.

We document the impact of withdrawal and injection into the basin from 2015 through 2021 on elevation change using Sentinel 1 InSAR data. We interpret these changes as reflecting significant geomechanical sensitivity including compaction of shale layers, reservoir pressurization and inflation, faulting of injection reservoirs, faults deflecting the ground surface, and induced earthquakes of multiple causes.

We observe an uplifted region of ~18,000 km2 with a maximum of 7 cm up and a total volume up of 155 million m3. Within the uplifted region is a domain of subsidence of ~16,000 km2 with a maximum of 18 cm down and a total volume down of 332 million m3. Subsidence correlates linearly with fluid volume produced, and the subsided region is closely coincident with production wells, spatially. A clean signal of production-caused subsidence comes from areas in New Mexico where shallow injection has been disallowed in recent years. The pattern of injection-caused uplift from reservoir inflation is far more complex because injection is everywhere conducted within the spatial footprint of production. There is a linear relationship between pore pressure increase from shallow injection and uplift but the footprint of uplift spreads laterally and significantly away from areas of injection. Shallow injection is causing seismic and aseismic fault rupture in the injection strata which is now manifest as linear features on the ground surface. The broad region of faulting is densifying and broadening. It appears likely that faults activated by injection are serving as pore pressure conduits controlling how the regions of uplift spread laterally away from areas of injection.

We believe this and related research can assist in managing the vitally important injection resource as a sustainable asset and assist in mitigating negative consequences.