摘要
四川盆地中侏罗统沙溪庙组是盆地致密气勘探的重要领域,具有埋藏浅、投资少、效益高等特点,目前核心建产区主要位于川西地区,急需从盆地尺度对沙溪庙组致密气成藏条件进行系统梳理,拓展勘探领域。基于沙溪庙组烃源岩、天然气来源、断裂发育研究,系统分析盆地内不同地区源储匹配关系,建立成藏模式,指出有利勘探方向。研究认为,四川盆地中侏罗统沙溪庙组天然气由上三叠统须家河组、下侏罗统自流井组及中侏罗统凉高山组共同供烃,天然气类型自西向东依次以煤型气、油型气、油型气—煤型气混合气为主;不同区域间成藏模式由于地质条件差异有显著的区别,川西地区以三叠系供烃、逆断层沟通的下生上储为主,川中地区以侏罗系内部供烃、正断层沟通的自生自储为主,川东地区以逆断层沟通的侏罗系自生自储为主、三叠系下生上储为辅。川西地区、川中北部地区及川东北部地区的沙溪庙组天然气成藏地质条件相对优越,勘探潜力相对较大,川中北部地区目前勘探程度较低,为下一步重点勘探突破地区。
The Middle Jurassic Shaximiao Formation is a major exploration field for tight gas in Sichuan Basin,which has the characteristics of shallow burial depth,low investment and high benefits.At present,the core production area is focused in the Western Sichuan Basin.Therefore,it is urgent to systematically summarize the tight gas accumulation conditions of Shaximiao Formation at basin scale,so as to expand the exploration field.Based on the study of source rock,natural gas source and fault development of Shaximiao Formation,configurations of source rock and reservoir assemblage are analyzed in detail and gas accumulation patterns established of different regions in the basin,and favorable exploration targets are put forward.The results show that natural gas of the Middle Jurassic Shaximiao Formation in Sichuan Basin is jointly supplied by source rocks of the Upper Triassic Xujiahe Formation,Lower Jurassic Ziliujing Formation and Middle Jurassic Lianggaoshan Formation.From west to east,the natural gas is mainly coal type gas,oil type gas and mixed oil type gas-coal type gas.The gas accumulation patterns vary significantly among different regions due to the different geological conditions.For example,gas reservoir in Western Sichuan Basin is mainly a lower generation and upper storage type supplied by the Triassic source rock and communicated by reverse faults.In the Central Sichuan Basin,it is dominated by a self-generation and self-storage gas reservoir supplied by the internal Jurassic source rock and connected by normal faults.While in Eastern Sichuan Basin,it is mainly a self-generation and self-storage gas reservoir supplied by the Jurassic source rock and supplemented by a lower generation and upper storage type gas reservoir supplied by the Triassic source rock and communicated by normal faults.Among them,Shaximiao Formation in Western Sichuan Basin,northern part of Central Sichuan Basin and northern part of Eastern Sichuan Basin has relatively superior geological conditions for gas accumulation and relatively large exploration potential.At present,exploration degree is low in the northern part of Central Sichuan Basin,which is the key exploration area in the near future.
作者
杨春龙
苏楠
芮宇润
郑越
王晓波
张欲清
金惠
Yang Chunlong;Su Nan;Rui Yurun;Zheng Yue;Wang Xiaobo;Zhang Yuqing;Jin Hui(PetroChina Research Institute of Petroleum Exploration&Development;CNPC Key Laboratory of Gas Reservoir Formation and Development;College of Geoscience and Surveying Engineering,China University of Mining and Technology(Beijing);University of Chinese Academy of Sciences)
出处
《中国石油勘探》
CAS
CSCD
北大核心
2021年第6期98-109,共12页
China Petroleum Exploration
基金
国家科技重大专项“大型气田成藏机制、富集规律与勘探新领域”(2016ZX05007-003)
中国石油天然气股份有限公司科技项目“复杂气藏成藏演化过程与定量表征”(2019B-0605)。
关键词
致密砂岩气
成藏模式
勘探潜力
沙溪庙组
侏罗系
四川盆地
tight sandstone gas
gas accumulation pattern
exploration potential
Shaximiao Formation
Jurassic
Sichuan Basin