Simulation Of Injection With Fracture Propagation Pressure

Now, water flooding is the most economical method to enhance recovery ratio, it was widely used in the whole world. But low permeability reservoirs often appear a phenomenon that water cannot be injected through injection wells and at the same time, oil cannot be produced from oil wells, so the energy of reservoirs decline sharply. In order to tackle with this problem, an effective method is injection with fracture propagation pressure. In order to evaluate the effective of this method, this paper built fracture grow-up model, the fracture model and matrix model; finally connected two models together through crossflow volume. In accordance with mathematical model, finite difference method was used to discrete model. This paper used computer language FORTRAN to develop simulator. After obtaining simulator, this paper simulated how the method of injection with fracture propagation pressure influences oil recovery ratio of reservoir. Firstly, respectively simulate how fracture orientation, water quality, injection rate, reservoir permeability and reservoir thickness affect recovery factor. The conclusion is: when the fracture orientation is 45°, the recovery factor is highest, compared with 90°and 0°; the quality of water have small influence on recovery factor; the more injection rate is, the bigger the degree enhance recovery factor of this method is, compared with the ordinary water flooding of low permeability reservoir; Through simulating the influence of permeability on exploitation effect of injection with fracture propagation pressure, this method is more suitable for lower permeability reservoir; reservoir thickness have a bit influence on recovery factor, and experiments indicated that the thicker thickness is, the better the effect is. Based on analysis of the single parameters, orthogonal experimental design was used to analyze the importance of every influencing factor and show that the order from most important one to the least one is fracture orientation, reservoir thickness, injection rate, water quality, reservoir permeability.