The Experiment And Numerical Simulation Research On Low Permeability Reservoir

The stress sensitivity phenomenon is notable in low permeability reservoir. The experiment research on the stress sensitivity is performed referring to the trade standard in present, but this experiment procedure is not consistent with the true course of stress changing. This paper improves the experiment method and equipment to research the stress sensitivity on the changing fluid pressure condition. It will induce errors to use the Terzaghi effective stress principle in the low permeability reservoir, so the double effective stress principle is introduced to research the stress sensitivity and fluid-solid coupling.This paper discusses the deformation mechanism of porous media, and reviews the development history of effective stress theory, and introduces the double effective stress theory. A new simple pore mechanics model is established based the pore structure of low permeability reservoir rock, from which the quadratic equation of effective stress and permeability can be educed.This paper carries sufficient experimental researches to learn the stress sensitivity of low permeability rock, and some experiments do referring to the trade standard and other do on the changing fluid pressure condition. The changing fluid pressure experiment method can reflects the actual changing path of reservoir stress, and eliminates the difference of the calculational results with different effective coefficient, and it provides the basic data of dynamic parameter model of fluid-solid coupled model. The stress sensitivity estimate is performed based the experimental results, and the new method is bring forward to estimate the actual reservoir rock. It also shows that the quadratic equation of effective stress and permeability is appropriate to the experimental data. The hysteresis effect of stress sensitivity is the appearance of the plastic deformation of rock, which is the reason of irreversible damage to the rock. This paper introduces the concept of permanent damage of reservoir physical properties such as permeability and porosity, and presents the calculational formula.The fluid-solid coupled phenomenon is evident in low permeability reservoir. On the bases of a great number of theoretical studies of former researchers and the effective stress theory, this paper set up the mathematical model of reservoir rock and the seepage flow equation. The effective stress coefficient distinguishes the different effective stress equation. The reservoir rock deformation equation is resolved with the...