四川叠合盆地西部中北段深层-超深层海相大型气田形成条件分析

发布时间：2018-05-04 14:59

本文选题：四川盆地 + 深层-超深层　；参考：《岩石学报》2017年04期

【摘要】：绵阳-长宁拉张槽的发现,大大地提升了四川叠合盆地西部深层-超深层海相层系的油气勘探前景。本文利用钻井、地震和野外露头资料和前人研究成果系统分析川西深层-超深层油气地质条件和目前发现的雷口坡组气藏的成藏过程。结果表明,四川叠合盆地西部深层-超深层海相层系有以下寒武统为主的多源供烃系统,多时代(震旦系灯影组白云岩,二叠系白云岩和礁滩体,三叠系雷口坡组微生物岩和颗粒白云岩等)储集层叠合,致密碳酸盐岩、巨厚陆相泥质岩和中下三叠统膏盐岩多级封盖,以断裂(及不整合面)和优质储层构成的立体输导网络等,使得深层-超深层海相层系具备形成大气田的基本条件,是原生气藏和次生气藏共存的天然气富集区。近年来,川西发现的中三叠统雷口坡组四段气藏,其可能成藏过程为生烃中心(下寒武统烃源岩等)→生气中心(灯影组和二叠系古油藏等)→储气中心(灯影组和二叠系古气藏等)→保气中心(雷口坡组次生气藏)。这揭示其深层-超深层既可能还存在着符合四中心耦合成藏的原生气藏,也可能发育着次生气藏,极有可能发现新的大气田。
[Abstract]:The discovery of the Mianyang-Changning extensional trough has greatly enhanced the prospects of oil and gas exploration in the deep-to ultra-deep marine strata in the western Sichuan superimposed basin. Based on drilling, seismic and outcrop data and previous research results, this paper systematically analyzes the geological conditions of deep and ultra-deep oil and gas in western Sichuan and the reservoir formation process of Leikoupo formation discovered at present. The results show that the deep-ultra-deep marine strata in the western Sichuan superimposed basin have the following Cambrian multi-source hydrocarbon supply systems, multi-epoch (Sinian Dengying formation dolomite, Permian dolomite and reef body). Triassic Lekoupo formation microbe rock and granulated dolomite, etc.) the reservoir is stratified, tight carbonate rock, superthick continental argillaceous rock and middle and lower Triassic gypsum salt rock multistage seal cap. The three-dimensional transport network composed of faults (and unconformities) and high quality reservoirs makes the deep-ultra-deep marine facies series have the basic conditions for forming large gas fields and is a natural gas accumulation area where primary gas reservoirs and secondary gas reservoirs coexist. In recent years, the fourth member of the Leikoupo formation of the Middle Triassic has been discovered in western Sichuan. The gas storage center (Dengying formation and Permian paleo-reservoir, etc.) and the secondary gas storage center (Leikoupo formation, etc.) during the process of reservoir formation may generate hydrocarbon (Lower Cambrian source rock, etc.). This indicates that the deep to ultra deep layer may also have primary gas reservoirs which are in accordance with the coupling of four centers, or may develop secondary gas reservoirs, so it is very possible to find new atmospheric fields.
【作者单位】：油气藏地质及开发工程国家重点实验室成都理工大学;
【基金】：国家自然科学重点基金项目(41230313) 中国地质调查局项目(121201021000150009)联合资助
【分类号】：P618.13

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