地质构造对煤层气井产能的控制机理与规律

Control Mechanism and Law of Geological Structure Affected to Production Capacity of Coal Bed Methane Well

探讨了构造演化与构造形态对煤层气井产能的控制机理,并结合沁南地区樊庄矿区实践,分析了构造对不同产能煤层气井分布的控制规律。研究表明:构造演化控制煤层气的整个成藏过程;后期构造形态对煤层气的运移和保存至关重要,褶曲两翼及向斜核部含气量高,背斜核部及开放性断层附近含气量低。同时对樊庄矿区研究表明:煤层气井产能与所处构造部位密切相关,高产井主要分布于褶曲构造翼部、复向斜的次级背斜核部及复背斜的次级向斜核部,日均产气量可达1 000～5 000 m3;低产井及产水井主要分布于复背斜的次级背斜核部及正断层断裂带附近,日均产气量小于500 m3。

The paper discussed the control mechanism of the structure evolution and structural shape affected to the production capacity of the coal bed methane well. In combination with the practices in Fenzhuang Mining Area of Qinnan Area, the paper analyzed the control law of the geological structure to the distribution of the coal bed methane wells with different production capacity. The study showed that the structure evolution would control the full accumulation process of coal bed methane. The later structure shape would be critical impor- tant to the migration and storage of the coal bed methane. The two wings of the fold and the syncline core would have high methane content and the anticline core and the open fault nearby would have low methane content. The study on the Fanzhuang Mining Area showed that the production capacity of coal bed methane well would have a close relationship to the structure location. The high production wells main- ly distributed at the wings of the fold structure, the subordinate anticline core of synclinorium and the subordinate syncline core of anticli-norium and the average daily gas production could reach to 1 000-5 000 m^3. The low production coal bed methane well and the water production well mainly distributed at the subordinate anticline core of anticlinorium and around the normal faults and the average daily gas production would reach to less than 500 m^3.