The Delaware Basin in West Texas and Southeast New Mexico has experienced a proliferation in seismic activity since 2016. The seismic activity is primarily due to subsurface injection of wastewater into both shallow and deep reservoirs. However, the precise mechanisms connecting pore-fluids to seismic activity is not well understood. To shed light on these processes, we measure rate-state friction and poromechanical properties of rocks sampled from the Delaware Mountain Group (DMG) at pressures and stresses representative of in-situ conditions. Experiments were conducted inside a pressure vessel and loaded in a true-triaxial stress state. The samples exhibit velocity-strengthening behavior and transition to a velocity-neutral behavior with increasing slip. We also measure frictional healing and demonstrate that the healing rates are consistent with those measured from quartz-feldspathic-rich rocks. Fault acceleration produces a transient increase in layer thickness (i.e, dilatancy), which in turn, reduces the local pore-pressure and causes dilatancy strengthening. Broadly speaking, the frictional and poromechanical data indicate that shallow faults within the DMG should favor aseismic creep as opposed to unstable slip. Hence, alternative mechanisms to an increase in pore-pressure being the direct causative agent to seismicity in the DMG need to be considered. We propose that seismicity in the DMG could be caused by a slip-weakening mechanism via a transition to velocity weakening behavior associated with shear localization at higher shear strains. Alternatively, seismic activity in the DMG could be a byproduct of aseismic creep as opposed to being triggered directly by the advancement of a pore-pressure front.