Experimental study on fracture propagation pattern of tight sandstone reservoirs in Daqing oilfield

The volume fracturing of tight oil in Daqing oilfield has achieved good effect, while the mechanism of fracture formation is not clear, which restricts the further improvement of technology. In order to clarify the fracture morphological characteristics of tight sandstone reservoirs in Songbei area of Daqing oilfield, a hydraulic fracturing simulation device was used to carry out a hydraulic fracturing physical simulation test on the natural tight sandstone cores under the true triaxial condition. The curve characteristics of the injection pressure and the fracture morphological change regularity of the cores were analyzed. The results show that the fracture morphology is mainly controlled by the horizontal principal stress difference, the influence of bedding characteristics on the fracture morphology is obvious, while the effect of brittleness index and Young's modulus on fracture morphology is not obvious. When the horizontal principal stress difference is less than 3 MPa, the reservoir stratigraphic characteristics are more obvious, it will be easier for hydraulic fractures to communicate with the weak surface of bedding and begin to turn after fracturing, and then the fracture morphology will become more complex.