摘要
四川盆地油气资源丰富,已被公认为超级油气盆地,近年来深层天然气展现出巨大的勘探开发潜力,走滑断层的识别及其控藏作用对于开拓断控型气藏勘探新领域具有十分重要的意义。为了进一步明确四川盆地中部地区(以下简称川中地区)走滑断层的分布及其与天然气勘探的关系,针对该盆地走滑断层规模小、断层复杂、地震资料质量差且受三叠系盐膏层褶皱变形影响大的特点,在川中地区连片三维地震资料解释的基础上,对走滑断层进行了识别并厘定了其特征、分布及成因,通过老井复查与油气成藏地质条件评价,建立了走滑断层断控气藏模式,进而探讨了断控气藏的勘探潜力与勘探方向。研究结果表明:①通过走滑断层剖面标志结合平面标志可以判识板内弱走滑断层;②在川中地区发现并落实了8条总长达1280 km的大型走滑断裂带;③走滑断层主要分布在震旦系—二叠系,以小位移的斜列、雁列断层为主,具有分层、分级、分类与分段的差异性;④受控于原特提斯洋斜向俯冲作用与基底差异结构,川中走滑断层形成于震旦纪,并存在加里东期—海西期的多期继承性活动;⑤川中地区走滑断层具有沟通源储、改善储层、聚气高产的作用,通过烃源岩—断层—储层构成“三元控藏、复式聚集”的断控天然气成藏系统。结论认为,四川盆地发育大型板内走滑断层系统,具有形成走滑断层断控大气田的成藏地质条件,大型通源走滑断裂带是断控碳酸盐岩天然气勘探突破的主攻方向。
The Sichuan Basin has abundant oil and gas resources and it has been generally acknowledged as a super petroliferous basin.In recent years,immense exploration and development potential of deep natural gas emerges in the Sichuan Basin.The identification of strike–slip faults and their reservoir controlling effects are of great significance to develop a new exploration domain of fault-controlled gas reservoirs.In order to clarify the distribution of strike–slip faults in the Sichuan Basin and their relationships with natural gas exploration,in view that the strike–slip faults in this basin are small and complex with poor seismic data and influenced more by the fold deformation of Tertiary gypsum salt beds,this paper identifies strike–slip faults and analyzes their characteristics,distribution and genesis based on the interpretation of continuous 3D seismic data of the central Sichuan Basin.Then,the fault-controlled gas reservoir model of strike-slip fault is established by reviewing old wells and evaluating geological conditions of hydrocarbon accumulation.Finally,the exploration potential and exploration direction of fault-controlled gas reservoirs are discussed.And the following research results are obtained.First,intraplate weak strike–slip faults can be identified by combining the seismic profile marker of strike–slip fault with the plane marker.Second,eight large strike–slip fault zones with a total length of 1280 km are identified and confirmed in the central Sichuan Basin.Third,strike–slip faults are mainly distributed in the Sinian–Permian System,mainly composed of small-displacement oblique faults and echelon faults,and different in stratification,grading,classification and segmentation.Fourth,under the control of the oblique subduction of the Proto-Tethys Ocean and the different structures of the basement,the strike–slip faults in the central Sichuan Basin were formed in the Sinian and there are multiple stages of inherited Caledonian–Hercynian activities.Fifth,the strike–slip faults in the central Sichuan Basin play a role in source–reservoir connection,reservoir reconstruction,and gas accumulation and high yield,and constitute the fault-controlled natural gas accumulation system of"three-element controlling reservoir and composite hydrocarbon accumulation"based on source rock,fault and reservoir.In conclusion,a large intraplate strike–slip fault system is developed in the Sichuan Basin,which has the geological conditions of hydrocarbon accumulation to form strike–slip fault-controlled large gasfield,and the large source connecting strike-slip fault zones are the main breakthrough directions of natural gas exploration in fault-controlled carbonate rocks.
作者
焦方正
杨雨
冉崎
邬光辉
梁瀚
JIAO Fangzheng;YANG Yu;RAN Qi;WU Guanghui;LIANG Han(China National Petroleum Corporation,Beijing 100007,China;PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610051,China;Southwest Petroleum University,Chengdu,Sichuan 610500,China)
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2021年第8期92-101,共10页
Natural Gas Industry
基金
中国石油天然气股份有限公司重大科技专项“四川盆地碳酸盐岩地球物理关键技术研究与应用”(编号:2016E-0604)
中国石油—西南石油大学创新联合体科技合作项目“深层/超深层碳酸盐岩天然气勘探开发基础理论与关键技术研究”(编号:2020CX010000)。
关键词
四川盆地
走滑断层
断层识别
断层分布
断控气藏
深层
油气成藏条件
天然气勘探方向
Sichuan Basin
Strike-slip fault
Fault identification
Fault distribution
Fault-controlled gas reservoir
Deep
Hydrocarbon accumulation condition
Natural gas exploration direction
