孔隙压力振动法渗透率测试研究

Determination on permeability by Pore Pressure Oscillation Method

岩石渗透率测试主要采用稳态法和以脉冲衰减法为主的非稳态法。孔隙压力振动法测试渗透率是介于稳态和非稳态之间的一种方法,该方法具有测试范围广的优点.本文开展了不同孔隙压力下的渗透率测试,结果与样品已知的渗透率值进行对比,发现该方法的渗透率测试结果稳定性好,准确性也好。通过不同测试条件下的实验研究,发现对渗透率高的样品应该采用较大的孔隙压力振幅和频率,而对于渗透率较低的样品应该采用较低孔隙压力的频率,从而提高上游室压力和下游室压力之间的振幅比和相位差,提高测试结果的准确性。

The permeability of rock was always determined by steady state method and unsteady state method.The pulse decay permeability test method is one of the most important unsteady state methods.Pore pressure oscillation method is intervenient from steady state method and unsteady state method and measures the low permeability and high permeability rocks.This paper analyzed the impact of pore pressure on permeability and compared the permeability with the standard results.It was indicated that the permeability,determined by pore pressure oscillation method,was steady and consistency on different test conditions.From various tests conditions,the test conditions were optimized to increase the ratio of amplitude and phase difference between upstream pressure and downstream pressure,so that the permeability will be more accuracy.The optimized test condition was that high pore pressure amplitude and frequency should be adapted on high permeability sample and low pore pressure amplitude and frequency should be adapted on low permeability sample.