Capillary force and boundary layer effect are the main causes of non-Darcy flow in tight oil reservoir. This paper proposes a non-Darcy flow dynamics characterization method for low-speed water flooding in tight oil reservoirs. It applies constant-speed mercury injection and casting thin section experiments to quantitatively characterize the micro-pore throat structure parameters, and uses the visual experimental device to measure the boundary layer thickness and fit the expression of the relationship between boundary layer thickness and displacement pressure gradient and fluid viscosity. The results show that the ratio of boundary layer thickness to microtubule radius changes exponentially with the pressure gradient and fluid viscosity and that the boundary layer thickness decreases gradually with the increase of pressure gradient. Given the capillary force and boundary layer thickness, the flow rate of single capillary is calculated. On this basis, the equation of nonlinear seepage dynamic characteristics per unit area of core is derived by taking into account the throat distribution frequency and throat size characteristics. The new seepage flow model can reflect the nonlinear seepage flow law of tight oil reservoir and provide reference for parameter formulation during water flooding development of tight oil reservoir.

中文翻译：

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致密油藏非达西流动渗透率计算方法

毛细管力和边界层效应是致密油藏非达西流动的主要原因。提出了一种致密油藏低速水驱非达西流动动力学表征方法。应用恒速压汞和铸造薄片实验定量表征微孔喉结构参数，利用可视化实验装置测量边界层厚度，拟合边界层厚度与位移压力梯度关系的表达式和流体粘度。结果表明，边界层厚度与微管半径的比值随压力梯度和流体粘度呈指数变化，边界层厚度随着压力梯度的增加而逐渐减小。给定毛细管力和边界层厚度，计算单个毛细管的流速。在此基础上，考虑喉道分布频率和喉道尺寸特征，推导出岩心单位面积非线性渗流动力学特性方程。新的渗流模型能够反映致密油藏非线性渗流规律，为致密油油藏注水开发参数制定提供参考。