Abstract: According to seepage law and material balance principle of single phase fluid in porous media, a one-dimensional theoretical model of heavy oil seepage is established based on micro-compressible property and non-linear flow of heavy oil in porous media. Two experimental methods of unsteady state seepage are designed to measure the threshold pressure gradient of heavy oil in porous media. Experimental pressure with time at the inlet of porous media was matched by adjusting the threshold pressure gradient during the two processes of constant flow injection and shutting the inlet, so the threshold pressure gradient of heavy oil in porous media was calculated at different temperatures. The threshold pressure gradient of heavy oil was more precise by calculating from shutting the inlet than constant flow injection. The reason was that the experimental method of shutting the inlet of porous media only measures pressure without considering oil phase flow at the inlet of porous media. The method has advantages of easily operation, rapid stabilization and high accuracy.

Key words: Heavy oil, Threshold pressure gradient, Experimental method, Experimental study

摘要： 根据多孔介质中单一流体的渗流规律及物质平衡原理，在考虑稠油微可压缩特性与非线性渗流特征基础上，建立一维稠油非线性渗流理论模型，以此为理论基础设计了两种非稳态渗流测压方式测定稠油拟启动压力梯度的实验方法。通过拟合恒流量注入过程与停止注入过程的多孔介质注入端测定的压力变化，从而计算出不同温度时稠油的拟启动压力梯度值。对比理论计算与稳定实验测定拟启动压力梯度的误差可知，关闭注入端测定注入端压力变化而求得的稠油拟启动压力梯度更精确，其原因是由于停止注入实验方法只需进行压力测量而无需考虑流量测量的问题，因此该方法实验简单易操作、实验时间短、计算精度高。

关键词: 稠油 , 拟启动压力梯度 , 实验方法 , 实验研究