Research on optimization of conductivity of multilevel fractures in tight sandstone based on similar circuit principle

Volume fracturing technology is commonly used to develop tight sandstone reservoirs. During the fracturing process, it is important to not only focus on achieving a larger stimulation volume but also on creating a fracture network conductivity that is suitable for the tight reservoir. However, while there have been numerous studies on optimizing the conductivity of individual fractures, the optimization of fracture network conductivity is still incomplete. To address this issue, a reservoir numerical model is established to optimize the equivalent conductivity of the post-fracturing fracture network, considering it as a high permeability zone, optimizing the equivalent conductivity to 9.7 mu m2 cm. Utilizing the discrete element theory, a "pipe domain" discrete element model is developed to analyze fracture expansion. The findings indicate that the ratios of first-level, second-level, and third-level fractures differ based on the number of clusters, such as 1:4:8 and 1:5:9 for three-cluster and four-cluster perforations. By applying the hydropower similarity principle, the fracture network is treated as a three-level circuit to determine the conductivity of each fracture level. Finally, the model is fitted based on conductivity to determine the optimal fracture conductivity for different fracture number ratios, thereby enhancing the flow capability. The post-pressure fracture network is equivalent to a high-permeability zone, and the reservoir numerical model is established to optimize the equivalent hydraulic conductivity of the fracture network. Based on the discrete element theory, the fracture expansion and its geometric parameters after volume fracturing of dense sandstone are simulated, and the equivalent hydraulic conductivity of the fracture network is optimized by combining with the theory of high-permeability zones. Drawing on the principle of hydropower similarity, the multistage fracture is equivalent to a circuit, and a three-stage circuit model is established. Combined with the numerical simulation results, the flow-conducting capacity of the cracks at all levels of the fracture network is optimized. image