气体滑脱因子快速实验测定的理论及方法

为了研究气体在多孔介质中渗流时的滑脱行为机理及其渗流规律，需要快速实验测定气体滑脱因子和低渗、特低渗岩心的绝对渗透率，常规方法须经多次测量方可获得一个滑脱因子和绝对渗透率值。为此，依据达西定理和波-马定律研究了一个压力容器内的理想气体经岩心自由渗流的过程，导出了描述岩心气测渗透率与容器内两不同时刻气体压力及其时间隔的关系式，从而提出了一种新的测试岩心气测渗透率的方法。由此可在气体经岩心自由渗流、容器内压力下降的过程中，用计算机计录下多个压力、时间点，并利用这些数据计算出多个气测渗透率值，再由克氏方程经最小二乘法拟合得出绝对渗透率和滑脱因子。该测试方法可在一次压力下降过程中完成对绝对渗透率和滑脱因子的测量，而且测量速度较快。

MECHANISM AND METHOD OF QUICK LABORATORY MEASUREMENT OF GAS SLIPPAGE FACTOR

To figure out the slippage mechanism and flow behavior of gas through porous media, it is necessary to quickly measure the gas slippage factor and absolute permeability of core samples with low and extra low permeability. Generally, conventional method takes times of tests to measure those parameters, therefore, based on Darcy's Law and Boyle Mariotte law, this study simulated a free flow process of gas through the core in a pressure container. From it, this study derived the relational expression between the measured permeability and gas pressures in the container at different time, and then put forward a new perm plug method. By this method, multiple pressures and time points need to be firstly recorded by a computer during the process of gas flowing through the sample while the pressure is decreasing inside the container, correspondent perm values can be secondly calculated using these recorded data, and the wanted absolute permeability and slippage factor can be finally acquired from Klinkenberg equation by least square regression. Thus, this measurement can be quickly completed during one pressure decline process.