川南长宁地区不同构造单元五峰组-龙马溪组流体包裹体特征及其地质意义  

Characteristics and geological significance of fluid inclusion of Wufeng-Longmaxi Formation in different tectonic units in Changning area,southern Sichuan

作　　者：梁志凯 姜振学[1,2] 吴伟 郭婕 王孟 刘冬冬[1,2] 聂舟[4] 薛子鑫 LIANG Zhikai;JIANG Zhenxue;WU Wei;GUO Jie;WANG Meng;LIU Dongdong;NIE Zhou;XUE Zixin(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing 102249,China;Unconventional Petroleum Science and Technology Research Institute,China University of Petroleum(Beijing),Beijing 102249,China;Shale Gas Research Institute,Petrochina Southwest Oil&Gas Field Company,Chengdu 610051,China;Exploration and Development Department of Sichuan Changning Natural Gas Development Co.Ltd,Chengdu 610051,China)

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)非常规油气科学技术研究院,北京102249 [3]中国石油西南油气田公司页岩气研究院,四川成都610051 [4]四川长宁天然气开发有限责任公司勘探开发部,四川成都610051

出　　处：《中南大学学报（自然科学版）》2022年第9期3652-3665,共14页Journal of Central South University:Science and Technology

基　　金：国家科技重大专项(2017ZX05035002);国家自然科学基金资助项目(41872135,41802153)。

摘　　要：川南长宁地区经历多期构造演化过程,页岩裂缝内部发育大量流体包裹体,利用流体包裹体进行气藏古温压恢复可为不同构造单元页岩气藏压力演化、保存条件研究提供重要依据。本文通过显微岩相学观察、流体包裹体测温、激光拉曼光谱分析、盆地数值模拟等方法,研究长宁地区双龙—罗场及天宫堂构造单元地质流体活动及古压力演化。研究结果表明:川南长宁地区脉体富含大量的气−液两相包裹体和气相包裹体以及少量沥青包裹体;不同构造单元流体充注期次存在差异,双龙—罗场向斜为2期流体充注,天宫堂背斜发生3期充注;长宁地区成藏过程划分为低压缓慢抬升、高压快速埋藏、高压缓慢调整、超压持续深埋和晚期抬升改造5个阶段;晚期抬升改造的强烈程度直接关系着页岩气能否形成气藏;双龙—罗场向斜超压原因是液态烃裂解生气造成超压,后期改造过程中超压未被完全破坏。天宫堂地区在抬升过程中受到NW和NE向叠加的挤压应力,形成NE向通天断裂,超压条件被破坏。The Changning area has experienced multi-stage tectonic evolution,and there are many fluid inclusions in shale fractures in southern Sichuan.Using fluid inclusions from the shale reservoirs to restore the paleo-temperature and paleo-pressure can provide vital information for studying pressure evolution and preservation conditions.Based on the microphotographic observation,fluid inclusion temperature measurement,laser Raman spectroscopy analysis and basin numerical simulation,the geological fluid activity and paleo-pressure evolution in Shuanglong—Luochang and Tiangongtang areas of Changning were studied.The results show that the veins are abundant in many gas-liquid two-phase inclusions,gas-phase inclusions and a small number of bitumen inclusions.The fluid charging periods of different tectonic units are different.Shanglong—Luochang syncline has two periods of fluid charging and Tiangongtang anticline has three periods of fluid charging.The accumulation process in the Changning area can be divided into five stages,i.e.,low-pressure with slow uplift,high-pressure with fast burial,high-pressure with slow adjustment,overpressure with continuous deep burial and late uplift transformation.The intensity of late uplift is directly related to the formation of shale gas reservoirs.The overpressure in Shanglong and Luochang syncline is caused by the pyrolysis of liquid hydrocarbon,and the overpressure is not destroyed in the later transformation process.In the uplift process,the Tiangongtang area is subjected to the superimposed compressive stress of NW and NE directions,forming the NE direction the considerable fault,and the overpressure condition is destroyed.

关 键 词：川南 五峰组—龙马溪组 天宫堂向斜 双龙—罗场向斜 流体包裹体 超压成因 盆地模拟 

分 类 号：P618.130.2[天文地球—矿床学]