Numerical simulation of crack propagation law and mechanism in conglomerate

Conglomerate reservoirs arereservoir is globally important, unconventional oil and gas reservoirs in the world. However, the gravel development formation leads to the strong heterogeneity of particles in the conglomerate reservoir. Hence, the research theory based on homogeneous rock is not applicable to these reservoirs, and the law of crack propagation and the mechanical mechanism areis in urgently needed to aid further researchneed of research. To study the effect of gravel content and cementation strength on the conglomerate deformation, the crack propagation process, and morphology, a numerical calculation model was established, based on the PFC2D discrete element software for discrete element modellingwas established, to simulate uniaxial compression experiments. The results indicate the followingthat: (1) The stress–-strain curve shows exhibits a multi-stage axial stress fluctuation during the loading process. The underlying reasons are the dislocation between the gravel and matrix and the interaction between the crack and gravel. (2) Weak cementation can easilyis easy to form a network of shear cracks at the edge of the gravel with ease edge. Under strong cementation, the crack propagateds through the gravel and hadexhibiteds a single shape. (3) The cementing interface between the gravel and the matrix wais prone to separation and fractures. In addition, the presenceexistence of gravel ledleads to the the transformation of the crack fracture path. ThereforeThese reasons, make the complexity of conglomerate cracks iswas controlled by the internal meso-structure. In tThis study, has grasped the influence law and mechanical mechanism of the strong heterogeneity of conglomerates on the crack - propagation process were investigated. The obtained resultsisIt can provide theoretical support for the design application of hydraulic fracturing technology in conglomerate reservoirs.