Numerical Simulation and Sensitivity Evaluation of Fracture Flooding in a Class III Reservoir

In this paper, based on studies of the fracture-flooding technology in a third-class reservoir, a mathematical model is established, conforming to the law of fracture initiation and propagation and the seepage mechanism of the surfactant-containing fracturing fluid. Third-class reservoir mathematical models are used to study the influence of fracture-flooding injection volume, displacement, reservoir permeability, effective thickness, remaining oil saturation, and other factors on the enhanced oil recovery effect in the fracture-flooding technology. The Sobol method is used to analyze the influence of various factors on the overall sensitivity of the enhanced oil recovery effect. The study shows that the cumulative oil increase is the major response variable for third-class reservoir fracture-flooding, the remaining oil saturation is the most sensitive factor, and the injection volume and effective thickness parameters are also sensitive. Thus, the oil-increasing effect of third-class reservoir fracture-flooding is mainly based on the remaining oil potential of the reservoir, expressed by the remaining oil saturation and effective thickness parameters, and the fracture range, defined by the fracturing fluid injection volume.