Calibration of Injection Reservoir Permeability and Pressure Modeling in a Case of Injection Induced Seismicity, Raton Basin, CO-NM

Abstract

The Raton Basin of Colorado and New Mexico had a sudden increase in seismicity beginning in 2001 that has been associated with the onset of large-scale wastewater injection operations in the region. A key parameter in understanding the relationship between injection and seismicity is injection reservoir permeability. Here, we analyze injection-recovery step rate tests of the main injection reservoirs, the Dakota Formation and the Entrada Formation, to establish calibrated permeability values for those formations. Both Theis injection and recovery analytical solutions are applied using AQTESOLV, an aquifer test analysis program. Our analysis produced a permeability range of 6.4 x 10^-14 m^2 to 6.8 x 10^-14 m^2 for the Dakota Formation and 5.8 x 10^-14 m^2 to 8.9 x 10^-14 m^2 for the Entrada Formation. Our results are consistent with the established permeability ranges for both formations detailed in the literature. We use these permeability values in our initial models of pore pressure change from injection wells to better understand subsurface pressure in the proximity of the active faults in the region. Subsurface pore pressure changes on the active faults are examined and reach levels great enough to induce seismicity. Future work will utilize a multiple-source transient management model and response matrix in order to optimize injection operations while mitigating injection-induced seismicity in Raton Basin.

AAPG Datapages/Search and Discovery Article #90372 © 2020 AAPG Pacific Section Convention, 2020 Vision: Producing the Future, Mandalay Beach, Oxnard, CA, April 4-8, 2020 (Cancelled)