Study On Fracture Network Influencing Factors Of Volume Fracturing In Tight Reservoir

As a more commonly stimulated reservoir technology,volume fracturing is widely used in the petroleum industry to increase the production of hydrocarbons.It is difficult to accurately predict and describe the fracture propagation morphology and stimulated reservoir effect of volume fracturing.Therefore numerical simulation technology has gradually become an efficient,convenient and accurate method for volume fracturing technology research.In this paper,a coupled numerical model by extended finite element method for hydraulic fracture initiation and propagation in porous media.The model contains the governing equations for fluid-solid coupling effects and the fluid flow equations within the fractures that satisfy Darcy's law.The fracture propagation law and fracture network area of the reservoir without natural fracture with different geological and engineering factors are simulated by using this numerical model.The results show that the Poisson's ratio and in-situ stress contrast have less influence on the fracture geometry;the high Young's modulus,Low Poisson's ratio and low in-situ stress contrast can effectively increase the area of ??the fracture network area;increasing the injection rate can effectively increase the fracture half length,the fracture width of injection point and the fracture network area;the fracturing fluid of high viscosity is easy to produce short and wide fractures,and produce a large fracture network area;the fracture spacing of 20-40 m can produce large fracture network area with simultaneously injection method.the optimal fracture spacing of the sequential fracturing is50 m.Two fractures fracturing with simultaneously injection method will produce a stress reversal zone,which is conducive to produce complex fracture network;the temporary plugging and diverting fracturing technology can effectively increase the area of the fracture network with the condition of high stress contrast,and the optimal temporary plugging fracture spacing is 50m;the closer the plugging location is to the wellbore,the larger the area of the fracture network formed and increasing the net pressure in the fracture can significantly increase the area of the complex fracture network.The research results in this paper provide a reference for the selection of construction parameters for reservoirs without natural fracture.