鄂尔多斯盆地韩城矿区中煤阶煤层气成藏模式

Accumulation Pattern of Medium Rank Coalbed Methane in Hancheng Mining Area,Ordos Basin

为揭示鄂尔多斯盆地韩城矿区中煤阶煤层气的成藏规律,综合应用钻井、测井、试井、煤岩测试和生产数据等资料,分析了韩城矿区的煤层气成藏条件和主控因素,并在此基础上研究了煤层气成藏模式。韩城矿区煤层气成藏条件有利,主力煤层全区发育且厚度可达12 m,煤层含气量为8~16 m^3/t,热演化程度较高,镜质体反射率为1.91%~3.06%,保存条件好;煤层气成藏主要受构造、水文地质和煤变质作用控制。依据构造形态、煤层围岩和地下水动力特征,把研究区的煤层气藏划分为低角度单斜式、鼻状构造式、边缘推覆式、缓坡背斜式和逆断层封闭式等5种成藏模式。

In order to reveal the accumulation of medium rank coalbed methane （CBM） in Hancheng mining area and using the data of drilling, logging, well testing, coal rock test and production, the conditions and main controlling factors of coalbed methane accumulation in Hancheng mining area are analyzed, based on which the CBM accumulation model is studied. The results show that the CBM accumulation conditions are favorable in Hancheng mining area-the key coal seams are widely distributed in the whole area with the thickness reaching 12 m, CBM content of 6-16 m^3/t, relatively high degree of thermal evolution, Ro of 1.91-2.56% and good preservation conditions. The CBM reservoir is mainly controlled by structures, hydrogeological conditions and coal metamorphism. Based on structural morphology, surround- ing rock conditions and groundwater dynamic characteristics, the reservoirs in the area can be divided into 5 patterns such as low-angle monocline, nose-like structure, marginal nappe, gentle slope anticline and sealed reverse fault,