Low Permeability Reservoir Injection Fluid Channeling And Seepage Mechanics Mechanism Research

High pressure water injection is the major producing method for low permeability reservoir. But during the injection process, channeling flow usually makes the water cannot displace oil. In this paper, diversified causes of channeling flow have been studied. In order to finish the research, in-house experiment, theoretical analysis and numerical simulation are used, and the coupling relation of seepage-failure has been considered through the consideration of the mechanical model of seepage-failure of interlayer. Based on numerical simulation, sensitivity analysis has been applied to the major elements of channeling flow. The research results are significantly meaningful for the theories and practices of water flooding in low permeability oil reservoir.This thesis mainly consists of the following parts:1. Rock samples from interlayer and oil bearing layers have been tested for rock mechanics and permeation fluid mechanics. From the tested parameters, the differences between interlayer and oil bearing layer have been studied;2. The effects of effective stress to permeability and porosity have been taken into account and defined into the constitutive relation of rock material. Furthermore, with the help of finite element analysis software ABAQUS, different kinds of causes of channeling flow have been simulated, and the law of the parameters of permeation within interlayer as well as its effect on channeling flow have been analyzed;3. Considering the coupling relation of seepage-failure, the mechanism and process of the failure of interlayer has been studied and numerically simulated;4. By using the mathematical software MATLAB, a program for comprehensively evaluating the factors of channeling flow has been produced, and has been applied in the sensitive analysis of major elements;5. Based on the anisotropy characteristics of cracks, the effects of various of natural and artificial cracks to the seepage field within reservoir and to the flow status of injected water have been studied;Finally, a certain district of Daqin oilfield has been studied considering the seepage-failure coupling relation. History matching simulation has been conducted, and the patterns and mechanism of channeling flow through interlays has been analyzed.