天然气扩散损失量估算方法探讨

经与实测扩散系数进行比较，认为用StokesˉEinstein方程式来进行扩散系数的预测计算是可行的。以物质平衡原理为基础，比较可排气量（可排气量=生气量-残留气量）与最大扩散气量，取二者中的小者为实际扩散气量。实际扩散气量随有机质丰度、生烃潜力、源岩厚度和顶面埋深的增大而增大。在一般地质情况下，计算所得最大扩散气量是实际扩散气量的几倍甚至几十倍，这使得在天然气资源量计算过程中，扩散气量被严重夸大了。

A discussion on m ethods for estim ating diffusion loss of natural gas

A study on the actual measured gas diffusion coefficient shows that calculating diffusion coefficient with the StokesˉEinstein equation is feasible.According to the mass balance principle，a comparison is carried out between the dischargeable gas（i.e.，the generated gasm inus residual gas）and themaximum diffused gas，amongwhich the smaller one is selected as the actual gas diffusion loss.The actual gas diffusion loss rises with an increase of organic matter abundance，hydrocarbonˉgeneration potential，source rock thickness and top burial depth.In a general geological condition，the calculated gas diffusion loss is several or even tens of times larger than the actual amount，causing an exaggeration of diffusion loss in the calculation of gas reserves.