Physical simulation of hydraulic fracture propagation innaturally fractured formations

Large-scale physical simulations are carried out to investigate the influence of natural fracture networks on propagation of hydraulic fracture. Based on practical geological and treatment parameters, experimental samples are prepared to generate random fractures inside, by heating at for 3 hours then cooling in the air. The results indicate that natural fractures exert great effect on hydraulic fracture propagation, at random to some degrees. The hydraulic fracture is a fracture system consisting of several main fractures of big size, and many fractures of small size. There is pressure fluctuation in pressure records, with the magnitude of several MPa to 8 MPa, corresponding to large fluid loss in treatment. So, high viscosity is preferred in treatment, to prevent from premature screenout.