浅论宁夏煤层气蕴藏条件及开发前景

Holding Environment and Exploitation Prospect of CBM in Ningxia

宁夏各含煤地层中有机质含高,具备煤层气形成的物质基础。通过对区内地层及构造与煤层气关系的研究,认为各含煤区顶底板为泥岩类,尤其是可塑性好的泥岩、炭质泥岩类,闭气性好;同一含煤地层中,泥岩分布区煤层气含量高于砂岩分布区;浅层高变质煤层也可具超级含气量,气体含量随埋深的增大呈线性状态增加;该区控煤构造以逆冲断层为主,易于煤层气蕴藏。预测2000m以浅各含煤地层中,煤层气储量在1000亿m3以上;深部煤层气含量必将远大于勘探期间所测值,具有很高的拓展空间。

Organic matter content is generally high in the coal-bearing strata in Ningxia, thus the material base to form CBM deposit. Through study of relations between the area＇s stratigraphy, structure and CBM, considered that coal roof and floor in each coal- bearing zone are argillaceous rocks, especially mudstone, carbonaceous mudstone with good plasticity, thereby have good airtight property. In same coal-bearing strata, CBM content in mudstone area is higher than in sandstone area. Shallow part high metamorphosed coal seams can also be super CBM contained, gas content increases along with coal seam deepening linearly. The coal controlling structures in the area are mainly reverse thrusts and in favor of CBM hosting. Predicted CBM resources above coal-bearing strata depth 2000m are more than 100 billion m^3; deep part CBM content will be far higher than estimated during exploration, thus a large expanding space.