首页|A hydromechanical-stochastic approach to modeling fluid-induced seismicity in arbitrarily fractured poroelastic media: Effects of fractures and coupling
A hydromechanical-stochastic approach to modeling fluid-induced seismicity in arbitrarily fractured poroelastic media: Effects of fractures and coupling
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NSTL
Elsevier
Decoupled hydro-shearing has been a classic mechanism of fluid-induced seismicity for decades. An alternative is coupled hydro-mechanical triggering, largely based on the theory of linear poroelasticity. Unfortunately, fractures and their alterations to a canonical poroelastic system are rarely accounted for, and seismicity is typically forecasted as event rate without producing catalogs. Here, I present a new approach to modeling fluid-induced seismicity in arbitrarily fractured poroelastic media. The hydro-mechanical triggering is modeled using a computational model that resolves fluid storage and nonlinear flow within fractures and full poroelastic coupling within the matrix. Seismological modeling is achieved stochastically by generating stress drops based on the full inter-seismic poroelastic stressing history. The two steps are sequentially coupled and advanced in time via a prediction-correction scheme, allowing for fracture stress updating and synthetic event catalog assembly. To demonstrate model capabilities and effects of fractures and full coupling on overpressure, stress, and seismicity, I perform three microseismic-scale numerical experiments by adding fractures and poroelastic coupling into a diffusion-only base model, and model previously unknown mechanisms. In contrast to existing models, this model produces both repeating and linear clustering of seismicity. Poroelastic coupling enhances the clustering, increasingly inhibits near-field seismicity and favors remote seismicity over time, and significantly reduces the overall event population. Meanwhile, statistical characteristics including the Gutenberg-Richter scaling relation persist, and the b-value elevation for microseismicity is attributable to a mechanical origin.
NSTL
Elsevier
