石油与天然气地质 ›› 2024, Vol. 45 ›› Issue (3): 722-738.doi: 10.11743/ogg20240311

• 油气地质 • 上一篇    下一篇

渤海湾盆地临南洼陷古近系沙河街组源-储组合类型与致密(低渗)砂岩油差异富集模式

韩载华1(), 刘华1,2(), 赵兰全3, 刘景东1, 尹丽娟3, 李磊1   

  1. 1.深层油气全国重点实验室 中国石油大学(华东),山东 青岛 266580
    2.海洋国家实验室 海洋矿产资源评价与探测技术功能 实验室,山东 青岛 266071
    3.中国石化 胜利油田分公司 勘探开发研究院,山东 东营 257100
  • 收稿日期:2023-12-24 修回日期:2024-05-31 出版日期:2024-06-30 发布日期:2024-07-01
  • 通讯作者: 刘华 E-mail:1339514178@qq.com;liuhua77@upc.edu.cn
  • 第一作者简介:韩载华(1994—),男,博士研究生,非常规油气地质。E‑mail: 1339514178@qq.com
  • 基金项目:
    国家自然科学基金项目(42272151)

Source rock-reservoir assemblage types and differential oil enrichment model in tight (low-permeability) sandstone reservoirs in the Paleocene Shahejie Formation in the Linnan Sub-sag, Bohai Bay Basin

Zaihua HAN1(), Hua LIU1,2(), Lanquan ZHAO3, Jingdong LIU1, Lijuan YIN3, Lei LI1   

  1. 1.State Key Laboratory of Deep Oil and Gas,China University of Petroleum (East China),Qingdao,Shandong 266580,China
    2.Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology,Qingdao,Shandong 266071,China
    3.Exploration and Development Research Institute,Shengli Oilfield Branch Company,SINOPEC,Dongying,Shandong 257100,China
  • Received:2023-12-24 Revised:2024-05-31 Online:2024-06-30 Published:2024-07-01
  • Contact: Hua LIU E-mail:1339514178@qq.com;liuhua77@upc.edu.cn

摘要:

为了揭示渤海湾盆地临南洼陷古近系沙河街组致密(低渗)砂岩油的差异富集机理,在依据空间配置和岩性组合划分源-储组合类型的基础上,综合利用测井、录井、试油和岩心分析测试资料,对不同源-储组合类型含油性及其供烃条件、储集条件、输导条件和运聚动力进行了分析,建立了致密(低渗)砂岩油差异富集模式。结果显示:①研究区存在源-储共生型(夹层型、互层型)、源-储紧邻型(源上型、源间型和源下型)、源-储间隔型(源下型)3大类6亚类源-储组合,对应3种致密(低渗)砂岩油富集模式。②源-储共生型具有“强供烃-强动力-高效充注-储集控富”模式,供烃条件和运聚动力最优,油气通过孔缝高效充注,储层含油性最好;相较于互层型,砂体厚度制约了夹层型油气富集规模。③源-储紧邻型具有“较强供烃-差异动力-联合输导-多元控富”模式,供烃条件较好,运聚动力变化大,油气通过孔缝-断裂-砂体联合输导,优先充注物性和孔隙结构好的储层,储层含油性较好;亚类中,源间型供烃条件和运聚动力优于源上型和源下型,含油性最好。④源-储间隔型具有“弱供烃-弱动力-断砂输导-输储控富”模式,供烃和运聚动力较弱,断裂、砂体组成的有效输导通道和优质储层发育对于油气富集至关重要,含油性整体较差。

关键词: 富集条件, 富集模式, 源-储组合, 致密(低渗)砂岩油, 古近系, 临南洼陷, 渤海湾盆地

Abstract:

This study aims to reveal the differential oil enrichment mechanisms of tight (low-permeability) sandstone reservoirs in the Paleogene Shahejie Formation in the Linnan Sub-sag, Bohai Bay Basin. Initially, we categorize the source rock-reservoir assemblages in the Linnan Sub-sag based on their spatial distribution and lithologic combination. The analysis on oil-bearing properties, hydrocarbon supply, reservoir storage spaces, conduit system, and migration and accumulation dynamics of various source rock-reservoir assemblages is carried out using an integration of data of logging, well tests, production tests and core analysis and tests. Accordingly, the differential oil enrichment model is established for tight (low-permeability) sandstone reservoirs. The results indicate that the source rock-reservoir assemblages in the study area can be categorized into three types, which can be further divided into six subtypes: the source-reservoir coexistence type, including interbedded and intercalated sub-types; the source-reservoir adjoining type, comprising three distinct subtypes with reservoirs located above, between, or below source rocks; and the source-reservoir separation type, including a subtype with reservoirs located below source rocks. These types correspond to three oil enrichment model of the tight (low-permeability) sandstone reservoirs. The source-reservoir coexistence type exhibits an oil enrichment model featuring “a strong hydrocarbon supply, strong migration and accumulation dynamics, efficient charging, and reservoir-controlled oil enrichment.” Specifically, this type boasts the optimal hydrocarbon supply conditions, the strongest migration and accumulation dynamics, and efficient hydrocarbon charging via pores and fractures, all of which contribute to the most favorable oil-bearing properties. Compared to that of the intercalated subtype, the hydrocarbon enrichment scale of the interbedded subtype is restricted by sand-body thicknesses. The source-reservoir adjoining type manifests an oil enrichment model characterized by a comparatively strong hydrocarbon supply, differential migration and accumulation dynamics, combined conduit systems, and multiple factor-controlled oil enrichment. In detail, this type features a comparatively favorable hydrocarbon supply, significant changes in the migration and accumulation dynamics, and combined conduit systems consisting of pores, fractures, faults, and sand bodies, with hydrocarbon preferentially charging reservoirs with favorable physical properties and pore structures. This type of source rock-reservoir assemblage exhibits comparatively favorable oil-bearing properties. Among others, its subtype with reservoirs located between source rocks outperforms the other two subtypes in terms of both hydrocarbon supply and migration and accumulation dynamics, thus demonstrating the optimum oil-bearing properties. The source-reservoir separation type displays a pattern characterized by a weak hydrocarbon supply, weak migration and accumulation dynamics, conduit systems including faults and sand bodies, and oil enrichment under the control of conduits and reservoirs. Due to the weak hydrocarbon supply and migration and accumulation dynamics, effective transport pathways composed of faults and sand bodies, along with the presence of high-quality reservoirs, are crucial to hydrocarbon enrichment. This type of source rock-reservoir assemblage generally exhibits inferior oil-bearing properties.

Key words: enrichment condition, enrichment model, source rock-reservoir assemblage, oil in tight (low-permeability) sandstone reservoirs, Linnan Sub-sag, Bohai Bay Basin

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