石油与天然气地质 ›› 2023, Vol. 44 ›› Issue (2): 429-440.doi: 10.11743/ogg20230214

• 油气地质 • 上一篇    

莺歌海盆地东方1-1气田中新统黄流组浅海多级海底扇形成机理及储层分布

李华1(), 杨朝强2, 周伟2, 何幼斌1(), 王玉2, 彭旋2, 李亚茹1, 吕欣博1   

  1. 1.长江大学 地球科学学院,湖北 武汉 430100
    2.中海石油(中国)有限公司 海南分公司,海南 海口 570312
  • 收稿日期:2022-07-10 修回日期:2022-12-08 出版日期:2023-04-01 发布日期:2023-03-17
  • 通讯作者: 何幼斌 E-mail:501026@yangtzeu.edu.cn;100709@yangtzeu.edu.cn
  • 第一作者简介:李华(1984—),男,副教授、硕士生导师,深水沉积及储层沉积学。E-mail: 501026@yangtzeu.edu.cn
  • 基金项目:
    国家自然科学基金项目(42272113);湖北省自然科学基金项目(2020CFB745)

Genetic mechanism and reservoir distribution of shallow-marine multi-stepped submarine fans in the Miocene Huangliu Formation of Dongfang 1-1 gas field, Yinggehai Basin

Hua LI1(), Zhaoqiang YANG2, Wei ZHOU2, Youbin HE1(), Yu WANG2, Xuan PENG2, Yaru LI1, Xinbo LYU1   

  1. 1.School of Geosciences,Yangtze University,Wuhan,Hubei 430100,China
    2.Hainan Branch,CNOOC,Haikou,Hainan 570312,China
  • Received:2022-07-10 Revised:2022-12-08 Online:2023-04-01 Published:2023-03-17
  • Contact: Youbin HE E-mail:501026@yangtzeu.edu.cn;100709@yangtzeu.edu.cn

摘要:

深海海底扇是沉积学领域及油气勘探的重要研究对象之一,而浅水海底扇研究相对较少。利用岩心、钻测井、地震及分析测试等资料,对莺歌海盆地东方1-1气田新近系中新统黄流组浅海多级海底扇的形成机理及储层分布规律进行了研究。研究表明:① 多级海底扇发育水道、席状砂及扇缘砂。其中,水道岩性为中-细砂岩,呈透镜状强反射地震特征,波阻抗较低。席状砂岩性以细砂岩及粉砂岩为主,平行层理发育,多为强反射地震特征,波阻抗低。扇缘砂以粉砂岩及泥岩最为常见,弱反射地震特征,波阻抗高。② 水道在研究区西北、中部及东南部发育,整体呈NW-SE向展布,可进一步分为3级,构成了多级海底扇的主体。席状砂发育在水道两翼及末端。扇缘砂多发育在海底扇边缘。③ 水道及席状砂沉积为有利储层微相,且席状砂储集性能略高于水道沉积。水道与席状砂沉积常断开不连通,席状砂与席状砂之间多不连通或弱连通,易形成岩性及地层圈闭。④ 多级海底扇的形成经历了早期的超临界流-临界流转换及晚期的充填-漫溢两个阶段。黄流组沉积早期,重力流能量高,超临界流-临界流转换可形成多级水道;随着重力流能量降低,流体转换作用减弱,重力流以充填-漫溢为主。

关键词: 重力流, 超临界流, 沉积微相, 有利储层, 海底扇, 黄流组, 新近系, 莺歌海盆地

Abstract:

Deep sea submarine fan is one of the key sedimentological subjects for oil and gas exploration, while shallow sea submarine fan is comparatively less documented. To fill up the gap, the shallow sea multi-stepped submarine fans in the Miocene Huangliu Formation of the Dongfang 1-1 gas field in the Yinggehai Basin are thoroughly investigated to determine their genetic mechanisms and distribution pattern of reservoirs by using core, drilling, seismic, lab test data, etc. The following results are obtained. ① The multi-stepped submarine fans host channels, sheet sands and distal silts, of which the channels are medium- to fine-grained sandstone with lenticular-shaped high-amplitude seismic reflections and low seismic impedance values, the sheet sands are dominantly fine-grained sandstone and siltstone with parallel beddings, showing high-amplitude seismic reflections and lower seismic impedance values (compared to channel deposits), and the distal silts are commonly mudstone and siltstone, showing low-amplitude seismic reflections and high impedance. ② The channels, forming the main parts of the fans in the northwest, middle, and southeast of the study area, are NW-SE oriented and can be divided into three steps. The sheet sands are developed at flanks and terminals of the channels. The distal silts are generally formed at the margin of the fan. ③ Both the channels and sheet sands are considered potential reservoirs with the latter being slightly higher in reservoir quality than the former. They are usually disconnected, quite ideal for the formation of lithological and stratigraphic traps. ④ The fans are suggested to have experienced an early supercritical to subcritical flow transform stage and a late filling-overbanking stage. During the early deposition of the Huangliu Formation, high-energy gravity flow led to the formation of multi-stepped channels via transformation from supercritical to subcritical flow; and during the late deposition of the Huangliu Formation, flow transformation was replaced by filling-overbanking as the gravity flow got weakened.

Key words: gravity flow, supercritical flow, sedimentary microfacies, potential resesrvoir, submarine fan, Huangliu Formation, Neogene, Yinggehai Basin

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