川南古叙矿区煤层气资源有利区优选

Assessment of the favourable areas of the coalbed gas resources in the Gulin Xuyong mining district in southern Sichuan

川南煤田二叠系龙潭组是重要的含煤层系,也是煤层气的主要赋存层段。古叙矿区是川南地区煤矿主要产区,煤层气资源丰富,在大村矿段已实现工业开采,其他矿段尚处勘探阶段。依托区域矿产地质调查,在分析区域煤层展布特征基础上,优选区域分布稳定的煤层C25、C23、C19、C17、C11为古叙矿区煤层气勘探目的层段。目的层段普遍具有有机质组分含量高、灰分含量中-高、内生裂隙发育、含气性高的特征,煤层累计厚度呈东厚西薄展布。以煤层厚度、构造条件、埋藏深度为主要评价指标,优选出大村矿段、石宝矿段为煤层气富集有利区,观沙矿段观文井田、古蔺矿段石屏-象顶井田及河坝矿段白头沟地区为煤层气富集较有利区。

The Permian Longtan Formation in southern Sichuan resides the important coal measures and coalbed gas resources. The Gulin Xuyong coal mining district as a major coal production area in southern Sichuan is very rich in the coalbed gas resources. In this study,the target strata are evaluated and delineated in the light of regional geological and mineral resource survey,and the distribution of the coal measures,including C25,C23,C19,C17 and C11 as the target coal measures for the coal exploration in the Gulin Xuyong coal mining district. The selected coal measures cited above are characterized by high contents of organic matter,high degrees of thermal evolution,medium to high ash contents,well developed endogenetic fractures and high contents of coalbed gas. According to coal thickness,regional structures and burial depth,the favourable areas for the enrichment of the coalbed gas resources may be delineated,including the Dacun and Shibao blocks,and relatively favourable areas consist of the Guanwen well area in the Guansha block,Shipin Xiangding well area in the Gulin block,and Baitougou well area in the Heba block.