山西沁水煤层气田煤层气成藏条件分析

沁水煤层气田单层煤层厚，分布在1～12m之间，一般大于6m，热演化程度高，R0分布在2．6％～3．7％之间，含气量大于14m^3／t，煤层气资源丰富。煤层气组分和碳同位素组成特征表明：沁水煤层气田热成因的煤层气在煤层中经历了解析-扩散-运移等作用，在构造高部位富集成藏，成藏期后的煤层气藏保存条件好，在上述3个因素的作用下．使得沁水煤层气田煤层气成藏条件较好，富含煤层气资源。

Analysis of conditions for the formation of a coal methane accumulation in the Qinshui coal methane field

Coal beds in the Qinshui coal methane field vary in thickness between 1 and 2 m, being generally 6 m thick. The degree of thermal maturity Ro ranges from 2.6% to 3.7% and the coal methane resources are abundant with a gas content of > 14 m3/t. The components and carbon isotopic composition of coal methane suggest that the coal methane of thermal origin in the Qinshui coal methane underwent deadsorption, diffusion and migration, it was concentrated and accumulated in the structural high, and the coal methane accumulation has been well preserved after its formation. Owing to the above-mentioned three factors, coal methane in the Qinshui coal methane field has good conditions of accumulation formation.