石油与天然气地质 ›› 2024, Vol. 45 ›› Issue (1): 113-129.doi: 10.11743/ogg20240108

• 油气地质 • 上一篇    

渤海湾盆地济阳坳陷东部深层砂砾岩多类型油气藏成藏机理及模式

雷文智1,2(), 陈冬霞1,2(), 王永诗3, 巩建强4, 邱贻博4, 王翘楚1,2, 成铭1,2, 蔡晨阳1,2   

  1. 1.中国石油大学(北京) 油气资源与探测国家重点实验室,北京 102249
    2.中国石油大学 地球科学学院,北京 102249
    3.中国石化 胜利油田分公司,山东 东营 257001
    4.中国石化 胜利油田分公司 勘探开发研究院,山东 东营 257015
  • 收稿日期:2023-07-16 修回日期:2023-10-12 出版日期:2024-02-01 发布日期:2024-02-29
  • 通讯作者: 陈冬霞 E-mail:18382244604@163.com;lindachen@cup.edu.cn
  • 第一作者简介:雷文智(1995—),男,博士研究生,油气成藏机理与分布规律。E‑mail: 18382244604@163.com
  • 基金项目:
    国家自然科学基金项目(41972124)

Accumulation mechanism and model of multi-type deep coarse-grained siliciclastic reservoirs in the eastern Jiyang Depression, Bohai Bay Basin

Wenzhi LEI1,2(), Dongxia CHEN1,2(), Yongshi WANG3, Jianqiang GONG4, Yibo QIU4, Qiaochu WANG1,2, Ming CHENG1,2, Chenyang CAI1,2   

  1. 1.State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum (Beijing),Beijing 102249,China
    2.College of Geosciences,China University of Petroleum (Beijing),Beijing 102249,China
    3.Shengli Oilfield Branch Company,SINOPEC,Dongying,Shandong 257001,China
    4.Exploration and Development Research Institute,Shengli Oilfield Branch Company,SINOPEC,Dongying,Shandong 257015,China
  • Received:2023-07-16 Revised:2023-10-12 Online:2024-02-01 Published:2024-02-29
  • Contact: Dongxia CHEN E-mail:18382244604@163.com;lindachen@cup.edu.cn

摘要:

渤海湾盆地济阳坳陷东部深层砂砾岩油气展现出良好的勘探前景,深层油气藏类型多样且成藏地质条件与中、浅层差异显著,其差异化地质特征的形成机理制约着深层油气勘探开发的进程。采用镜下薄片观察、储层流体包裹体分析和盆地模拟等方法,分析了深层储层孔隙类型及地层压力存在差异的原因,进而建立了济阳坳陷深层砂砾岩多类型油气成藏模式。结果表明:①储层成岩演化揭示了深层储层不同孔隙类型的形成机制,深层砂砾岩储层中原生粒间孔隙的保存为早期油气充注和超压流体共同作用的结果,烃源岩生烃充注酸性 流体引发的溶蚀反应是次生溶蚀孔隙形成的关键,储层中超压环境有助于微裂缝发育,形成孔-缝型储集空间。②深层流体超压演化受到生烃作用和沉积过程的控制,超压环境的形成取决于保存条件,构造-岩性油气藏中压力的分布受断-砂输导体系调配。在深层常压-弱超压储层中,源-储剩余压力差为稳定和充足的成藏动力;而在超压储层中,源-储剩余压力差随着时间推移逐渐减弱。在断层发育区和垂向连通性强的砂体中浮力是油气二次运移、调整的主要动力。③基于生烃-储层-压力对济阳坳陷东部深层砂砾岩油气成藏的耦合控制作用,建立了多期叠置近岸水下扇油气相态垂向分异型、近岸水下扇泥岩顶部及侧向联合封堵型、近岸水下扇-浊积扇近源成藏型3种油气成藏模式。济阳坳陷深层多类型砂砾岩油气藏成藏机理和模式的揭示为后续深入勘探奠定了坚实的基础。

关键词: 储层成岩演化, 压力演化, 深层砂砾岩体, 深层油气成藏, 济阳坳陷, 渤海湾盆地

Abstract:

Deep coarse-grained siliciclastic rocks in the eastern Jiyang Depression, Bohai Bay Basin hold great potential for oil and gas exploration. Given the presence of various types of deep coarse-grained siliciclastic reservoirs and the significant geological differences in hydrocarbon accumulation between the deep and the medium-to-shallow reservoirs in the depression, there is an urgent need to understand the formation mechanisms behind these differentiated geological features in order to advance the exploration and exploitation of deep oil and gas reserves. Employing techniques such as thin-section microscopy, reservoir fluid inclusion analysis, and basin simulation, we investigate pore types in the deep reservoirs and the origin of differentiated formation pressure in the Jiyang Depression. The accumulation models of various types of deep coarse-grained siliciclastic reservoirs in the depression are established thereby. The key findings are as follows: (1) The diagenetic evolution reveals the formation mechanisms of the various pore types of reservoirs. The preservation of primary intergranular pores in the deep coarse-grained siliciclastic reservoirs is attributed to the combined effects of early hydrocarbon charging and overpressured fluids. In contrast, the secondary dissolved pores in the reservoirs are developed largely due to dissolution reactions induced by acidic fluid charging during the hydrocarbon generation of source rocks. In addition, the overpressure in the reservoirs facilitates the development of microfractures. All these lead to the formation of pore-fracture reservoir spaces; (2) The evolution of fluid overpressure in the deep reservoirs is governed by hydrocarbon generation and depositional process. The formation of overpressure environment hinges on preservation conditions, and the pressure distribution in hydrocarbon reservoirs within structural-lithologic traps is regulated by the fault-sand body transport system. In deep normal pressured-weakly overpressured reservoirs, the residual pressure difference between source rocks and reservoirs serves as the primary driving force to hydrocarbon accumulation. While in overpressured reservoirs, this residual pressure difference gradually decreases over time. Furthermore, buoyancy provides the main driving force for the secondary migration and adjustment of hydrocarbons in areas with well-developed faults and in sand bodies with good vertical connectivity; (3) Based on the joint control of hydrocarbon generation-reservoir-pressure on hydrocarbon accumulation, we establish three hydrocarbon accumulation models for deep coarse-grained siliciclastic reservoirs in the eastern Jiyang Depression, including the model of vertically differentiated hydrocarbon accumulation in multi-phase superimposed nearshore subaqueous fans, the model of top-lateral joint hydrocarbon sealing by mudstone within nearshore subaqueous fans, and the model of near-source hydrocarbon accumulation within nearshore subaqueous fans-tubidite fans. The elucidation of these hydrocarbon accumulation mechanisms and models of multi-type deep coarse-grained siliciclastic reservoirs in the Jiyang Depression lays a solid foundation for subsequent in-depth exploration.

Key words: diagenetic evolution of reservoirs, pressure evolution, deep coarse-grained siliciclastic rock, hydrocarbon accumulation in deep reservoirs, Jiyang Depression, Bohai Bay Basin

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