泥质岩盖层对扩散相天然气的封闭作用及研究方法

在深入分析天然气通过盖层扩散作用及其影响因素的基础上,对泥质岩盖层封闭扩散相天然气作用及影响因素进行了分析,提出泥质岩盖层对扩散相天然气的3种封闭作用,即依靠浓度的封闭作用、依靠浓度和自身品质的封闭作用和依靠自身品质的封闭作用。并根据气藏与盖层之间含气浓度差、天然气通过盖层扩散系数和厚度,通过对气藏与泥质岩盖层之间含气浓度差、泥质岩盖层扩散速度和单位浓度差下的天然气通过盖层扩散速度的计算,探讨了泥质岩盖层对扩散相天然气3种封闭能力的研究方法。实例应用结果表明这些研究方法是可行的,可以客观地反映泥质岩盖层的实际封闭能力。 

THE CONFINING OF ARGILLACEOUS CAP ROCKS ON NATURAL GAS OF DIFFUSION PHASE AND ITS APPROACH

Based on a thorough study of the diffusion of natural gas through the cap rocks and its influential factors, the sealing of argilliaceous caprocks on natural gas in diffusive phase is analysed, suggesting that the sealing argillaceous cap rock on natural gas in a diffusion phase includes three forms, i. e a sealing (1) dependent of concentration, (2) of concentration and the quality of itself and (3) of the quality of itself.Considering the concentration difference of gas between a gas pool and its cap rock, the calculations of the diffusion rate of argillaceous cap rock and the diffusion rate of natural gas under unit concentration difference through the cap rock, etc. the authors inquire into the methods to study the three types of sealing capabiIity of argillaceous cap rock on natural gas in diffusion phase. The results of case study show that these methods are available, and can objectively reflect the actual sealing capability of argillaceous cap rocks.