歧口凹陷埕北断坡不整合与油气藏关系
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摘要
在油气运聚体系中,不整合起着至关重要的作用,在歧口凹陷埕北断坡,从古近纪初期至新近纪,发生多次湖侵和湖退,地层遭受多期抬升剥蚀,发育多期不整合接触,主要有古近系底界不整合、古近系与新近系之间的不整合等。为了剖析埕北断坡不整合在油气运聚过程中的作用,本文利用对地震、测井、取心等资料,对区内不整合的类型、纵向分层特征以及纵向结构模式进行综合研究。研究表明:不整合具有上、中、下3层结构,根据3层结构中的岩性配置差异,该区不整合存在3种纵向结构模式:其中ACE型与ADE型是构成该区油气运移的重要通道,BCE型输导能力相对前两型较差。不整合面作为主控因素形成多种类型的油气藏,埕北断坡区主要存在超覆不整合油气藏和削截不整合油气藏两类地层油气藏。超覆不整合油气藏主要发育于古近系沙河街组内部,以及新近系的馆陶组底界不整合,而削截不整合油气藏主要发育于中生界顶界不整合。
In the oil-gas transport and accumulation system, unconformity plays a vital role. On the Chengbei fault-slope of Qikou sag, from Paleogene to Neogene, the events of lake transgression and lake regression have happened frequently to cause strata being uplifted and corroded. Unconformity is developed at the bottom of Paleogene and Neogene Systems. In order to study the role of the unconformity in the oil-gas transport and accumulation system, the seismic data and well data are used to make comprehensive research for type, layer and structure mode of unconformity. Studying results show that the unconformity is constituted by the rock above unconformity, weathered layer and half-weathering layer. According to the configuration differences of the lithology, three-layer structure modes of unconformity are defined, i.e., ACE, ADE, and BCE, of them the ACE and ADE constitute the migration channel of oil-gas, and the conducting ability of BCE is poorer. The unconformity can form various types of oil and gas reservoirs. There are two types of stratigraphic reservoirs in Chengbei fault-slope: overlying unconformity reservoir and abrupt changeable unconformity reservoir. The former exists in the Shahejie Formation and Guantao Formation; the latter exists in the top of Mesozoic.
In the oil-gas transport and accumulation system, unconformity plays a vital role. On the Chengbei fault-slope of Qikou sag, from Paleogene to Neogene, the events of lake transgression and lake regression have happened frequently to cause strata being uplifted and corroded. Unconformity is developed at the bottom of Paleogene and Neogene Systems. In order to study the role of the unconformity in the oil-gas transport and accumulation system, the seismic data and well data are used to make comprehensive research for type, layer and structure mode of unconformity. Studying results show that the unconformity is constituted by the rock above unconformity, weathered layer and half-weathering layer. According to the configuration differences of the lithology, three-layer structure modes of unconformity are defined, i.e., ACE, ADE, and BCE, of them the ACE and ADE constitute the migration channel of oil-gas, and the conducting ability of BCE is poorer. The unconformity can form various types of oil and gas reservoirs. There are two types of stratigraphic reservoirs in Chengbei fault-slope: overlying unconformity reservoir and abrupt changeable unconformity reservoir. The former exists in the Shahejie Formation and Guantao Formation; the latter exists in the top of Mesozoic.
引文
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高长海,查明,陈力,等,2016.渤海湾盆地冀中坳陷大柳泉构造不整合输导油气能力的定量表征[J].天然气地球科学,27(4):619-627.
何登发,2018.“下削上超”地层不整合的基本类型与地质意义[J].石油勘探与开发,45(6):995-1006.
麻伟娇,王峰,宋明星,等,2017.不整合面上底砾岩控制油气运聚的流体证据[J].特种油气藏,24(1):81-86.
苏磊,2017.TN凹陷不整合结构及其油气地质意义[J].大庆石油地质与开发,36(4):33-39.
陶士振,袁选俊,侯连华,等,2017.大型岩性地层油气田(区)形成与分布规律[J].天然气地球科学,28(11):1613-1624.
王文楷,许国明,淡永,等,2018.川西地区雷口坡组顶部不整合面特征及其对储层的影响[J].中国岩溶,37(4):592-601.
杨少春,鲁鹏善,赵永福,2018.高青地区中生界顶部不整合结构特征及输导作用[J].大庆石油地质与开发,37(4):32-37.
张娟,2018.不整合在凸起区油气成藏中的作用-以太平油田为例[J].石油地质与工程,32(3):17-20.