Abstract:
The hydraulic fracturing simulation system under triaxial confining pressure was used to construct the fracture propagation model under different geological factors and construction factors. The fracture propagation characteristics of staged fracturing were analyzed by fracturing data and model cutting methods, and the influencing factors of fracture propagation were discussed. The results show that: ①The horizontal stress difference and overburden structure mainly affect the fracture propagation pattern of staged fracturing, and have little effect on the fracture propagation scale.②The cementing strength of structural plane is one of the most sensitive factors of fracture. When the cementing strength is less than 0.50 MPa, the fracture propagation extends along the bedding plane and cannot develop through the layer. When the cementing strength is greater than 0.75 MPa, the fracture can develop through the structural plane.③The construction factors such as construction displacement and fracturing section spacing are highly sensitive to the influence of fracturing cracks. With the increase of liquid injection displacement, the crack propagation and extension are more straight. When the fracturing section spacing is small, it is obviously affected by the "stress shadow effect". Appropriately increasing the fracturing section spacing is conducive to the development of fracturing cracks. The research results can provide technical support for the staged fracturing weakening transformation of hard roof.