Models of Injection‐Induced Aseismic Slip on Height‐Bounded Faults in the Delaware Basin Constrain Fault‐Zone Pore Pressure Changes and Permeability

Abstract

Abstract Inversions of InSAR ground deformation in the Delaware Basin have revealed an aseismic slip on semi‐optimally oriented normal faults located close to disposal wells. The slip, occurring over 3–5 years, extends approximately 1 km down‐dip, over 10 km along strike, and reaches 25 cm. We develop and calibrate 2D and pseudo‐3D coupled pore pressure diffusion and rate‐state models with velocity‐strengthening friction tailored to this unique height‐bounded fault geometry. Pressure diffusion is limited to a high‐permeability fault damage zone, and the net influx of fluid is adjusted to match the observed slip. A 1–2 MPa pressure increase initiates slip, with ∼5 MPa additional pressure increase required to produce ∼20 cm slip. Most slip occurs at approximately constant friction. Fault zone permeability must exceed ∼10 −13 m 2 to match the along‐strike extent of slip. Models of the type developed here can be used to operationally manage injection‐induced aseismic slip.