摘要
分布在四川盆地东北部的各个飞仙关组鲕滩圈闭在成藏过程中具有极为相似的地质条件,但不同区块流体性质复杂多变,油气成藏过程差异明显,深化勘探面临瓶颈。为揭示油气成藏机制,基于海槽东侧岩心、薄片观察,结合生物标志化合物、流体包裹体微区测试、构造平衡剖面恢复等手段,认为飞仙关组局限台内相区储层由(膏质)粉晶云岩构成,油气充注不充分;台地边缘相储层由鲕粒云岩组成,经历三期成藏事件:(1)J2到J3早期的古油藏形成阶段,(2)J3到K1的龙潭组生气阶段,(3)K2的古油藏裂解生气阶段。总结提出沉积亚相、储层物性、圈闭形成时期、古今构造搭配关系等5种因素控制了鲕滩气藏成藏过程,形成了4种成藏模式。台地边缘相区作为后续勘探的重点领域,对应其中3种模式:(1)圈闭形成早,古今构造有效搭配,断层未至地表;(2)圈闭被当直达地表的断层破坏,致使油气逃逸;(3)圈闭形成晚于关键成藏事件,古油藏向更高部位发生横向运移。
Traps of Feixianguan Formation distributed in northeastern Sichuan Basin have very similar basic geological conditions during hydrocarbon accumulation,but the fluid properties of different areas are complex and changeable,and the oil and gas accumulation process are obviously different,so the deepening exploration is difficult.In order to reveal the mechanism of hydrocarbon accumulation,based on the observation of cores and thin sections of eastern K-L Trough,combined with biomarkers,fluid inclusion microzone test and structural equilibrium profile restoration,it is suggested that the reservoir in the restricted platform interior subfacies of Feixianguan Formation is composed of(gypsum-bearing)very finely crystalline dolostone,and corresponding oil and gas charging is insufficient.The platform margin subfacies reservoir is composed of oolitic dolostone,which has experienced three episodes of accumulation events:①the early formation stage of J2 to J3,②the gas generation stage of Longtan Formation of J3 to K1,③the gas generation stage of the gas cracking stage of K2.It is proposed that five factors,including sedimentary subfacies,physical properties,trap formation period,and paleo-present structural collocation,control the accumulation process of oolitic shoal gas reservoirs,and form four accumulation models.As the key area of subsequent exploration,the platform-margin area develops three models:①The trap was formed early,the ancient and modern structures were effectively combined,and the faults did not reach the surface;②The trap is destroyed by the fault directly to the surface,resulting in oil and gas escape;③The trap formation was later than the key accumulation event,and the paleoreservoir migrated laterally to higher positions.
作者
钟芬
陆廷清
杨长城
何冰
邓惠
徐昌海
张洁伟
谷一凡
ZHONG Fen;LU Ting-qing;Yang Chang-cheng;He Bing;Deng Hui;XU Chang-hai;ZHANG Jie-wei;GU Yi-fan(School of Geoscience and Technology,Southwest Petroleum,Chengdu 610500;Gas Field Development Management Department of PetroChina Southwest Oil and Gas Field Company,Chengdu 610000;Research Institute of Petroleum Exploration and Development PetroChina Southwest Oil and Gas Field Company,Chengdu 610041;Northeastern Sichuan Oil and Gas District,PetroChina Southwest Oil and Gas Field Company,Dazhou,Sichuan 635000)
出处
《四川地质学报》
2023年第1期100-106,共7页
Acta Geologica Sichuan
基金
中国石油天然气股份有限公司重大科技专项“西南油气田天然气上产300亿立方米关键技术研究与应用”(2016E-06)。
关键词
飞仙关组
鲕滩
成藏模式
流体包裹体
储层沥青
开江-梁平海槽
Feixianguan Formation
oolitic shoal
hydrocarbon accumulation model
fluid inclusion
reservoir bitumen
K-L Trough
