After physical property change of radial pore medium saturated by single phase fluid was analyzed under low-frequency vibration,influence of low-frequency vibration oil recovery on the actual reservoir flow with various pressure gradients near the wellbore may be known. The control equations for elastic wave propagating were established,which shows the influence of the low-frequency vibration on the initial flow of the radial reservoir. Considering the consistency of directions of elastic wave and initial Darcy flow around the wellbore,physical model meshing was made according to the mapped meshing and boundary mesh refinement to weaken the boundary spurious reflection. By comparing coupled vibration flow with Biot flow and initial radial flow based on finite element simulation of COMSOL system,it is demonstrated that the numerical simulation can reveal the effectiveness of periodic changes of reservoir physical property under the influence of the low-frequency vibration according to the difference in semi-analytical solution. The research results present that the coupled vibration flow is not simply equal to the sum of Biot flow and initial radial flow. The low-frequency vibration has obvious function of increasing the seepage velocity and permeability and decreasing the injection pressure in the radial flow field when the vibration source is in the injection well;the effect is more obvious near the injection well. The local maximum pressure decrease ratio reaches 40%,and the action range with significant velocity increase is 10 m to the center of wellbore. The effect is more obvious at lower permeability and higher porosity.
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ZHENG Liming, PU Chunsheng, LIU Jing. Influence of low-frequency vibration oil recovery on the initial flow of radial reservoir[J]. Petroleum Geology and Recovery Efficiency,2018,25(1):68~76