Microscale modeling of fluid flow‐geomechanics‐seismicity: Relationship between permeability and seismic source response in deformed rock joints

Abstract

Key Points:• Hydro-mechanical-seismic modeling is applied to model joints behavior • Nonshear displacement affects transport and seismic behavior of joints • Confining pressure affects transport and seismic behavior of joints Supporting Information:• Readme • Figure S1 • Figure S2 • Figure S3 • tkdensityCase6 Abstract Studying rock joint deformation including both slippage and opening mechanisms provides an opportunity to investigate the connection between the permeability and seismic source mechanisms. A microscale fluid flow-geomechanics-seismicity model was built to evaluate the transport response and failure mechanism of microcracks developed along a joint in Berea sandstone samples during deformation. The modeling method considers comprehensive grain-cement interactions. Fluid flow behavior is obtained through a realistic network model of the pore space in the compacted assembly. The geometric description of the complex pore structure is characterized to predict permeability of the rock sample as a function of rock deformation by using a dynamic pore network model. As a result of microcracks development, forces and displacements in grains involved in bond breakage are measured to determine seismic moment tensor. Shear and nonshear displacements are applied to the joint samples to investigate their effects on permeability evolution and failure mechanism of microcracks during joint deformation. In addition, the effect of joint roughness is analyzed by performing numerical compression tests. We also investigate how confining pressure affects volumetric deformation leading to opening or closure of developed microcracks and permeability changes of samples with joints.

Fully Dynamic Spontaneous Rupture Due to Quasi‐Static Pore Pressure and Poroelastic Effects: An Implicit Nonlinear Computational Model of Fluid‐Induced Seismic Events

“…This approach naturally accommodates arbitrary geometries of discontinuities at a microscale; the governing laws are typically discretized and solved using the popular Particle Flow Code (Itasca Consulting Group, 1999). This technique was initially employed to simulate microseismicity in dry brittle rocks (Hazzard & Young, 2004) and then extended to study fluid-induced microseismicity (Raziperchikolaee et al, 2014;Yoon et al, 2014;Zhao & Young, 2011). Compared to the previously mentioned modeling, this technique provides additional information on source mechanisms like seismic moment tensors.…”

Experimental Investigation of the Effects of the Gangue Particle Size on the Evolution Rules of Key Seepage Parameters

“…By combining laboratory test, theoretical analysis, and field application, Ma et al examined non-Darcy hydraulic characteristics and deformation behaviors of bulk gangues and concluded that both porosity and permeability of gangues increased with the increase of the original GSG and the decrease of the stress rate [20]. Raziperchikolaee et al focused on the relation between permeability of the deformed rock joints and seismic source response, established the fluid flow-geomechanics-seismicity model at microscale, and investigated the displace response and failure mechanisms of microfractures in the sandstone samples that were developed along the joint during the development [21]. Li et al investigated the effects of the particle size on compressive deformation and particle damage of the filling gangues in the goaf and analyzed the compressive deformation, particle clustering distribution, and gauge bulk shape change rules of the filling gangues [22].…”

Statistical based hydromechanical models to estimate poroelastic effects of CO2 injection into a closed reservoir

“…Coupled hydromechanical modeling is typically used for evaluation of the poroelastic effect of injection as well as the resulting geomechanical outcomes such as the potential for fracturing in reservoirs, analysis of slippage along faults, surface uplift, and associated seismicity . Different numerical approaches including finite element method, finite difference method, discrete element method, and boundary element method have been used to address in situ stress changes and rock deformation . Combinations of different methods have also been developed to address the poroelastic response of injection.…”

“…8,[16][17][18][19][20][21][22] Different numerical approaches including finite element method, finite difference method, discrete element method, and boundary element method have been used to address in situ stress changes and rock deformation. [23][24][25][26][27][28] Combinations of different methods have also been developed to address the poroelastic response of injection. One commonly used tool is TOUGH-FLAC modeling, which is based on linking the finite-volume code for the simulation of multiphase fluid flow (TOUGH2) with the finite-difference code for the simulation of geomechanics (FLAC), and has been extensively used to predict stress changes that might activate the faults and induce seismicity.…”