沁水盆地山西组煤储层含气性及控制因素分析

GasBearing Characteristics and Geological Factors of the Coal Seam No.3 in the Northern Qinshui Basin, Shanxi

依据实测资料，在统计分析研究区３号煤层含气性特征的基础之上，对控气地质机理进行了探讨．总体上来看，研究区甲烷含量较高及甲烷浓度较大，而含气饱和度偏低．在埋深１０００ｍ以浅，向盆地内部方向以及随煤层埋深加大，甲烷含量、甲烷浓度和含气饱和度具有增大趋势，显示出埋深控气以及次级向斜相对富气的特点，这种特征可能起源于地质历史时期中煤层抬升卸压过程所导致的煤层气解吸扩散作用．因此，进一步查明次级构造的发育展布特征，精细分析其与煤层含气性特征之间的相互关系。

Based upon the measured data, the gasbearing characteristics of the coal seam No.3 in the studied area are statistically analyzed. In general, the seam is relatively high in coalbed methane (CBM) content and concentration but is rather low in methane saturation. The CBM content, concentration and saturation in the seam with less than 1 000 m of burial depth tend to increase with the decrease of distance to the center of the basin and the increase of burial depth, showing the characteristics of the CBM occurrence controlled by burial depth and the CBM accumulation in secondary syncline. These could be resulted from the CBM desorption and diffusion derived from the elevation and load reduction of coal seam in the geological history. Thus, to ascertain the distribution of secondary structures and the their correlation to gasbearing characteristics is of vital importance for predicting the gasbearing characteristics of coal reservoirs and arranging the CBM wells.