Numerical investigation of fluid-driven crack propagation and coalescence in granite specimen with two pre-existing flaws

摘要: Abstract Natural oil-gas-bearing rock formation generally contains a large number of discontinuities, which have influence on the cracking process inside under high water pressure condition. Hence, good understanding propagation and coalescence fluid-driven cracks is important to improve oil gas exploitation efficiency. This study numerically investigates crack in specimen possessing two pre-existing flaws using fluid coupled discrete element method. The micro-parameters are first calibrated against mechanical properties Lac du Bonnet granite. numerical models generated by installing with different ligament angles, length, flaw angles. injection test constant rate then conducted patterns these pre-cracked models. results show that relatively angle better accelerate paralleled flaws. Numerical model small length inclined traverse area. Overall, this reveal significant effect much attention should be paid behavior when many discontinuities associated formation.