| 渝东南盆缘转换带五峰组-龙马溪组常压页岩气保存条件评价 |
| |
| 引用本文： | 刘义生,金吉能,潘仁芳,李笑天,朱正平.渝东南盆缘转换带五峰组-龙马溪组常压页岩气保存条件评价[J].地质科技通报,2023,42(1):253-263. |
| |
| 作者姓名： | 刘义生 金吉能 潘仁芳 李笑天 朱正平 |
| |
| 作者单位： | 1.长江大学地球科学学院, 武汉 430100 |
| |
| 基金项目： | “十三五”国家科技重大专项2016ZX05061-001国家自然科学基金青年基金项目41804120 |
| |
| 摘 要： | 四川盆地及其周缘上奥陶统五峰组-下志留统龙马溪组页岩广泛发育，页岩气资源丰富，盆地内五峰组-龙马溪组页岩气已获得大规模商业突破。渝东南盆缘转换带处于构造变形强烈区域，相对于盆内五峰组-龙马溪组页岩气富集过程，需要对保存条件的评价提出更高的要求。为此，针对渝东南盆缘转换带复杂的构造格局，通过对构造演化、抬升剥蚀、断裂发育、构造样式、顶底板条件、地层压力等多因素叠合分析，开展了保存条件的研究。结果表明，盆缘转换带抬升剥蚀严重，断裂发育，形成了一系列残留构造样式；距离剥蚀边界、大断层近的区域内，五峰组-龙马溪组均有天然气逸散的情况，地层压力系数普遍小于1.2；桑拓坪向斜、武隆向斜大断裂发育较少，五峰组-龙马溪组在远离剥蚀区具有良好的页岩气保存条件。因此后期抬升剥蚀和断裂发育是天然气散失后常压形成的主要原因；尽管由盆内向盆外地层压力系数由超压转变为常压，但构造形成了窄陡残留背斜、宽缓残留向斜和残留斜坡的页岩气保存形式。最后建立了渝东南盆缘转换带常压页岩气保存条件的评价标准，划分了3类有利目标区。
|
| 关 键 词： | 渝东南 盆缘转换带 常压页岩气 保存条件 五峰组-龙马溪组 |
| 收稿时间： | 2021-12-06 |
Preservation condition evaluation of normal pressure shale gas in the Wufeng and Longmaxi Formations of basin margin transition zone,Southeast Chongqing |
| |
| Affiliation: | 1.School of Geosciences, Yangtze University, Wuhan 430100, China2.Exploration and Development Research Institute of PetroChina, Changqing Oilfield Company, Xi′an 710000, China |
| |
| Abstract: | Despite the huge gas resources in the shale of the Upper Ordovician Wufeng Formation and Lower Silurian Longmaxi Formation in the Sichuan Basin and its periphery, commercial breakthroughs are mainly located inside the basin.The Southeast Chongqing, located in the basin margin transition zone, was intensively deformed by tectonic activities. As compared to the gas enrichment model of the Wufeng-Longmaxi Shale inside the basin, the basin margin transition zone requires better preservation conditions.According to the complicated structure patterns of the Wufeng and Longmaxi Formations in Southeast Chongqing, the preservation conditions are analyzed by the super position of structure evolution, uplift and exhumation, fault development, structural style, roof and floor conditions, and formation pressure. The results show that the basin margin is seriously uplifted and exhumated, with well-developed faults, forming a series of residual structural styles; natural gas leakage in the area close to the exhumation boundary and major faults contributed to the low formation pressure coefficient (less than 1.2). Sangtuoping syncline and Wulong syncline show good preservation conditions of shale gas because of the relatively less large faults and the far away from the exhumation area. Therefore, the late uplift, exhumation, and fault development are the main reasons for the gas leakage and the change of formation pressure from overpressure to normal pressure across the basin margin. Tectonic deformation is the fundament of current shale gas preservation in the structures of narrow and steep residual anticlines, broad and gentle residual synclines, and residual slopes. Finally, an evaluation standard was established for the preservation conditions of normal-pressure shale gas. According to this standard, favorable target areas are divided for normal shale gas in the study area. |
| |
| Keywords: | |
|
| 点击此处可从《地质科技通报》浏览原始摘要信息 |
|
点击此处可从《地质科技通报》下载全文 |
|
