Recent inversions of InSAR ground surface deformation in the Delaware Basin have revealed aseismic slip on conjugate, semi-optimally oriented normal faults. Slip, occurring over 3-5 years, extends approximately 1 km down-dip, over 10 km along strike, and reaches 23 cm. Several disposal wells are located nearby, suggesting that pressure changes from injection might have induced slip. We develop and calibrate 2D and pseudo-3D coupled pore pressure diffusion and rate-state models with velocity-strengthening friction. Pore 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 pressure increase of 1-2 MPa is required to initiate slip. Most aseismic slip occurs at approximately constant friction and ~5 MPa additional pressure increase is needed to reach ~20 cm slip. Our work suggests that models of the type developed here can be used to operationally manage injection-induced aseismic slip.