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

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 m² to match the along-strike extent of slip. Models of the type developed here can be used to operationally manage injection-induced aseismic slip.