在深入分析影响天然气扩散作用因素的基础上,认为浓度是天然气发生扩散的根本原因。指出:不同浓度适用于不同的地质条件,游离相含气浓度适用于天然气在不含水岩石中的扩散;水中溶气浓度适用于天然气在饱和水岩石中扩散,认为孔隙水中总溶气浓度较孔隙水间填充溶气浓度更符合天然气在地下岩石中扩散的实际情况;采用不同的浓度计算得到的天然气扩散量大小是不同的,采用游离相含气浓度计算得到天然气扩散量较实际值偏大,而采用孔隙水间隙填充溶气浓度计算得到的天然气扩散量又较实际值偏小,只有采用孔隙水中总溶气浓度计算得到的天然气扩散量才符合实际情况,孔隙水中的总溶气浓度是引起天然气在地下岩石中发生扩散的真正浓度。

Based on analyzing the influencing factor of gas diffusion,this paper considered the concentration was the basic factor for gas to diffuse. Different concentrations are fit in with different geological conditions. Concentration in free phase is fit in with diffusion of gas in no water-filled rocks. Concentration dissolved in water is fit in with diffusion of gas in water-saturated rock. Total contraction dissolved in wa ter is more fit in with actual situation of gas diffusion in underground rocks than the concentration of gas interstitially dissolved in water molecules is.Diffusion amounts of gas calculated by the concentration in free phase is larger than the actual value.The diffusion amount of gas calculated by the concentration of gas interstitially in water molecules is smaller than the actual value.The diffusion amount of gas calculated by total concentration of gas dissolved in water is fit in with the actual geological situation.Therefore,the total concentration of gas dissolved in water is the concentration causing gas to diffuse in undergroung rocks.