褐煤煤层气储集特征及气含量确定方法

CBM storage character of lignite and gas content estimate method

摘要: 褐煤基质中的孔隙以中孔、大孔为主。实验表明,褐煤对甲烷的吸附能力很低;褐煤基质中的游离气含量通常占总气含量的50%以上。因此,传统的煤层气含量确定方法不适用于褐煤。本文建立了褐煤煤层气含量的确定方法,将吸附气含量与相应储层压力及温度条件下的游离气含量相加,即得到褐煤总的气含量等温线。利用这条等温线,即可获得该温度下不同储层压力时的气含量值。

Abstract: In the lignite matrix,the porosities are mainly meso-and macroporosities.Experiments show that the adsorption capacity of lignite is low.The free gas in the lignite matrix is more than 50 percent of total gas.Therefore,the conventional gas content measurement is invalid to lignite.The gas content measurement for lignite has been established in this paper,joining the free gas content to the adsorption gas content at the same temperature,the total gas content isotherm can be obtained.The gas content value at same temperature but different pressure can be obtained with this isotherm.