Numerical Simulation Investigation of Fracture Propagation Behavior Patterns and Sensitivity Factors of Oil Shale Reservoirs in the Xunyi Region Considering the Influence of Natural Fracture

Abstract

Shale oil and gas resources are considered one of the most important strategic resources globally today. However, the matrix permeability of oil shale reservoirs is extremely low, it requires modification through hydraulic fracturing technology to realize their economic and effective development. Against this background, we focused on the oil shale in the Xunyi area of the Ordos Basin, employing the ABAQUS platform to simulate and investigate the characteristics of hydraulic fracturing fracture propagation in fracture-developed oil shale reservoirs and the principal influencing factors. The results of the study show that the larger the angle between the natural fracture and the hydraulic fracture, the easier it is for the hydraulic fracture to pass through the natural fracture; the larger the elastic modulus of the matrix, the stronger the ability of the fracture to penetrate through the stratum, and the fracture morphology tends to be more narrow and long. The direction of fracture propagation tends to be in the direction of the geostress difference, and with the increase of the geostress difference, the degree of convergence of the direction of fracture propagation and penetration is greater. The higher the viscosity of the fracturing fluid, the wider and shorter the fracture tends to be, but it has minimal impact on the direction of fracture propagation. Increasing the fracturing fluid displacement can increase the fracture width and length and enhance the effect of the hydraulic fracturing modification. The research results are significant for the optimized fracturing design in oil shale reservoirs.