扩散系数实验技术研究

STUDIES ON THE EXPERIMENTAL TECHNIQUE OF DIFFUSION COEFFICIENT

在应用以费克（FICK）第二定律为理论依据的扩散系数计算方法及自行设计的岩石扩散系数检测设备技术的基础上，进行了重复性及不同条件下对扩散系数的影响实验，探讨了温度、压力等因素影响扩散作用的机理。认为在扩散系数检测过程中，应采取恒定的温度、围压与初始测试气体压力才能避免由于不同条件变化给扩散系数测试带来的影响。通过试验区含气丰度不同的气藏盖层样品扩散系数与渗透率实验研究，盖层扩散系数小于lO～crn2／s的区域在该地区能够形成有效封盖，大于10～cm2／s的区域难形成有效盖层，而且随扩散系数减小对油气封闭保存更有利。

On the bases of the calculating method of diffusion coefficient theoretically established by FICK No. 2 Law and the instrument detecting technique of rock diffusion coefficient, the influencing experiments of the repeatility and different conditions on the diffusion coefficient are conducted, the mechanisms of the influencing actions by constant temperature, surrounding pressure and so forth are explored. The studies show that in the course of the coefficient detection, only by means of the above temperature, surrounding pressure and initially tested gas pres- sure, can the influences on the detection of the diffusion coefficient under the changes of different conditions be avoided. Through the experimental researches on the relation between the diffusion coefficient and permeability of the rock samples for the gas cap rock with different gas-bearing abundances in the test area, the region with the coefficient less than 10-4cm2/s in the area can establishes effective sealing; for the region larger than 10-4cm2/s, it is difficult to form the same sealing, and moreover with the reduction of the diffusion coefficient, the sealing and conservation for the hydrocarbon are much more favorable.