An integrated field scale computational model for hydraulic conductivity of high energy explosive driven fracturing

A novel integrated computational model is proposed for the efficient and accurate simulation of the combined effects of underground explosions in geomaterials and the resultant hydraulic conductivity. For accurate characterization of field scale fracture geometries dual-support smoothed particle hydrodynamics (DS-SPH) approximations are established to extract aperture field dispersions. Then, voxel-based modellings with 3D octree decomposition techniques are adopted to represent the complex geometrical and topological properties of explosive driven fracture networks for turbulence modelling. As such, the construction of nonlinear mathematical formulations for fluid flow simulations through explosively driven fractures is derived based on a set of kinematic and topological assumptions. The accuracy and sensitivity of the proposed nonlinear fluid flow simulations are investigated for the spherical and cylindrical explosive charges by comparison with RLE, RANS simulations, theoretical solutions, and field experimental observations. Nonlinear fluid flow simulations in current research study reveal the effect of explosive-driven fracturing anisotropy and heterogeneity on non-Darcy fluid flow behavior. Findings depict that the computational solutions are mainly affected by turbulent flow in hydrodynamic zone near the explosive source, while transition to the laminar regime at larger radial distances and near to the fracture tip. For the spherical explosive charges, turbulence flow dominates due to the shorter fracture length and the larger variations in local fracture aperture fields around the blast borehole. The newly proposed computational model precisely estimates turbulent permeabilities and characterizes the nonlinear fluid flow simulations in explosive-driven fractures with rough surfaces and variable apertures and correlates well with multiple sets of experimental data from various field sites.