Heavy oil reservoirs feature in high viscosity,non-Darcy flow,and the existence of start-up pressure. According to the percolation characteristics of heavy oil reservoir,a reasonable method for measuring the start-up pressure was designed. The start-up pressure gradient of oil phase and the relationships between velocity and pressure gradient under irreducible water saturation was studied through various percolation experiments at different viscosity, permeability and temperatures conditions with the natural cores from Xinjiang oilfield. The experimental formulas of start-up pressure gradient, velocity-differential pressure curve parameters, mud logging-derived permeability, and fluid viscosity were established through experimental data regression. These experiments indicate that the start-up pressure of heavy oil reservoir can be determined rapidly and accurately with the experimental method. The influences of oil viscosity on start-up pressure gradient are greater than that of reservoir physical properties. The start-up pressure gradient and velocity-pressure curve parameters are well correlated with the ratio of mud logging-derived permeability to fluid viscosity.%稠油油藏原油粘度高,流体渗流不符合达西定律,其流动时存在启动压力.根据稠油油藏渗流特点,设计了合理确定稠油启动压力的实验测试方法.通过对新疆油田稠油油藏不同原油粘度、不同渗透率、不同温度条件下天然岩心的渗流实验,研究了束缚水饱和度下油相启动压力梯度及流速-压差关系,并对实验数据进行回归,得到了启动压力梯度、流速-压差曲线参数与岩石气测渗透率、流体粘度关系的经验公式.实验结果表明,利用该测试方法能快速、准确地测定稠油油藏的启动压力.原油粘度对稠油启动压力梯度的影响大于储集层物性的影响.稠油启动压力梯度及描述流速-压差曲线的参数和岩石气测渗透率与流体粘度比值有很好的相关性.
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