Effect of Porosity and Permeability Evolution on Injection‐Induced Aseismic Slip

Abstract

Fluid injection has been associated with the triggering of seismic events in geologically stable regions that previously had minimal detected seismicity (McGarr et al., 2015). Injection is done in the context of wastewater disposal and hydraulic fracturing in oil and gas operations, carbon sequestration, and geothermal energy production (

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

“…We calibrated the model by adjusting q 0 to approximately match the 25 cm maximum slip after 3 years; Figure 2b also shows results for q 0 that is a factor of two greater or lesser than the optimal value, illustrating the sensitivity of pressure change and slip to q 0 . Slip begins after a quiescent period of approximately 170 days, consistent with other studies (Dublanchet, 2019;Larochelle et al, 2021;Yang & Dunham, 2021). During this quiescent period, pressure at the injector increases and diffuses to other parts of the fault, decreasing the effective normal stress.…”

“…We adopt the quasi-dynamic approximation with radiation damping parameter η rad = 0.5µ/c s (µ, is elastic shear modulus and c s is shear wave speed) (Rice, 1993). We integrate the governing equations with an adaptive time-stepping method (Allison & Dunham, 2018;Erickson & Dunham, 2014;Yang & Dunham, 2021;Zhu et al, 2020). Equations 1 and 2 are used to compute the friction coefficient, which is used in the elasticity problem through the fault boundary condition.…”

“…For both models, we consider only a single fault, representative of the central fault in Figure 1b, as our goal is to understand the processes controlling aseismic slip on height-bounded faults, seeking some consistency with observations to ensure relevance of the modeling results, but not matching all specific details of this problem. We begin with the 2D model of Zhu et al (2020) and Yang and Dunham (2021), in which a planar fault is embedded in a linear elastic medium, and the 1D fluid transport and pore pressure diffusion equation is solved simultaneously with the friction and elasticity problem. Our model approximately solves the 2D problem on a vertical cross-section orthogonal to the strike of the fault, resolving pressure diffusion and slip in the down-dip direction while assuming invariance along strike (Text S2 in Supporting Information S1).…”

A spectral boundary-integral method for faults and fractures in a poroelastic solid: Simulations of a rate-and-state fault with dilatancy, compaction, and fluid injection

“…Second, how altering the bulk diffusivity and undrained Poisson's ratio influences the fault response from injection. Dilatancy is already understood to be a stabilizing mechanism (Rudnicki & Chen, 1988;Segall & Rice, 1995;Segall et al, 2010), although limited study of coupled injection and dilatancy has been carried out (except Ciardo & Lecampion, 2019;Yang & Dunham, 2021).…”

“…Multiple mechanisms may act at a time. Recently, numerical simulations have started exploring the simultaneous injection and inelastic dilatancy in a diffusive shear zone (Ciardo & Lecampion, 2019;Yang & Dunham, 2021). However, these efforts have been limited to a non-diffusive and elastic bulk.…”