Petroleum Exploration and Development Research Institute, SINOPEC East China Company

基于延川南煤层气田构造研究,结合2号煤层水质分析、试井及分析化验资料,探讨了构造、水文地质条件对煤层气赋存的控制作用。研究表明:单斜构造和逆断层封堵决定了研究区发育2种不同的水文地质单元,具有不同的水力控气特征。谭坪构造带位于弱径流区,埋藏浅,压力梯度低,属于水力封堵控气,煤层水具有低矿化度,弱碱性,水型为Na+-HCO3-型的特征;万宝山构造带位于滞留区,埋藏深,承压水封堵,压力梯度高,煤层水具有高矿化度,弱酸性,水型为Ca2+-Cl-型的特征,属于水力封闭控气。万宝山构造带2号煤层平均含气量15.3 m3/t,谭坪构造带平均9.2 m3/t,万宝山构造带煤层气赋存条件优于谭坪构造带。

Based on a structure study of a coal bed methane gasfield in Yanchuannan Block, in combination with the water quality analysis of No. 2 seam, logging a s well as analysis and chemical test information, the paper discussed the structure and hydrogeological conditions affected to the control role of the coal bed methane d eposition. The study showed that a monoclinal structure and reverse fault sealed decided two different hydrogeological units developed in the study area with different h ydraulic gas contral features. Tanping structure zone was located in a weak runoff area and was shallow in a deposition depth and low in a pressure gradient. The struct ure zone was gas controlled with the hydraulic sealing. The seam water had a low mineralization and a weak alkalinity and the water type had Na+- HCO3type features. Wanbaoshan structure zone was located in a detention area with a deep deposition depth. The pressurized water was sealed and the pressure gradient was high. The s eam water had a high mineralization and a weak acidity. The water was in Ca (2 +) - Cltype features. The seam was air controlled with hydraulic sealing. No. seam in Wanbaoshan structure zone had a gas content of 15. 3 m3/ t in average. Tanping structure zone had a gas content of 9. 2 m3/ t in average. The coal bed methane depo sition condition in Wanbaoshan structure zone was better than Tanping structure zone.

国家科技重大专项资助项目(2011ZX05035-006)；