Study on the Evolution Law of Shale Hydraulic Fracture Interacting with Bedding Layer under Pulsation Loading

Abstract

Abstract The bedding layers in shale reservoirs are highly developed with numerous bedding joints. In the hydraulic fracturing process, the propagation of hydraulic fractures during shale formation significantly affects the efficient development of reservoirs. In this study, we employed the pulsating cyclic loading technique to develop a model of the interaction between shale hydraulic fractures and bedding layer; in addition, we used a numerical model optimization method for the zero-thickness cohesive element to compare the hydraulic fracture and bedding layer propagation behavior under static and pulsating loading. We studied the propagation behavior of pulsating fracturing bedding layers at different frequencies, amplitudes, and bedding angles. The results revealed that static load fracturing is more conducive to the propagation of primary fracture under the same conditions, and that pulsation fracturing is better for the propagation of bedding layer. The higher frequency and amplitude of the seismic source in the pulsation fracturing process are more favorable to crossing the bedding layers. When the bedding angle is approximately 10°, turning the main fracture along the bedding direction is challenging. The hydraulic fracture along bedding layer propagation was achieved when the bedding angle was approximately 30° and 45°. When the bedding angle was approximately 60° or more, the fracture extended only along one side of the bedding layer. The study results provide guidance for the formation of fracture networks in the field of fracturing construction of shale reservoirs, thus improving the production of shale reservoirs.