石油学报 ›› 2020, Vol. 41 ›› Issue (6): 671-690.DOI: 10.7623/syxb202006003

• 地质勘探 • 上一篇    下一篇

莱州湾凹陷北洼沙河街组三段砂岩储层孔隙定量演化模式

王彤1,2, 朱筱敏1,2, 张自力1,2, 刘宇1,2, 郭诚3, 李卓3   

  1. 1. 中国石油大学(北京)地球科学学院 北京 102249;
    2. 油气资源与探测国家重点实验室 北京 102249;
    3. 中海石油(中国)有限公司天津分公司 天津塘沽 300459
  • 收稿日期:2019-09-23 修回日期:2020-02-03 出版日期:2020-06-25 发布日期:2020-07-11
  • 通讯作者: 朱筱敏,男,1960年6月生,1982年获华东石油学院勘探系石油地质专业学士学位,1990年获石油大学矿产普查与勘探专业博士学位,现为中国石油大学(北京)教授、博士生导师,主要从事层序地层学和储层沉积学方面的教学和科研工作。Email:xmzhu@cup.edu.cn
  • 作者简介:王彤,女,1995年8月生,2017年获中国石油大学(北京)学士学位,现为中国石油大学(北京)地质学专业硕士研究生,主要从事层序地层学和测井地质学研究工作。Email:tovawang0821@outlook.com
  • 基金资助:

    国家科技重大专项"陆相湖盆层序地层与岩性圈闭形成机制"(2017ZX05001-002-002)资助。

Q uantitative pore evolution model of sandstone reservoirs for Member 3 of Shahejie Formation in the northern subsag of Laizhouwan sag

Wang Tong1,2, Zhu Xiaomin1,2, Zhang Zili1,2, Liu Yu1,2, Guo Cheng3, Li Zhuo3   

  1. 1. College of Geosciences, China University of Petroleum, Beijing 102249, China;
    2. State Key Laboratory of Petroleum Resources and Prospecting, Beijing 102249, China;
    3. Tianjin Branch, CNOOC China Limited, Tianjin 300459, China
  • Received:2019-09-23 Revised:2020-02-03 Online:2020-06-25 Published:2020-07-11

摘要:

莱州湾凹陷位于渤海湾盆地南部,是一个"小而肥"的富烃凹陷,其储层成岩作用的研究程度较低。铸体薄片、扫描电镜、X射线衍射和阴极发光等多种技术手段的分析结果显示,莱州湾凹陷沙河街组三段中—深层储层的岩性主要为中粒—细粒岩屑长石砂岩,其成分成熟度和结构成熟度为中等偏好,属于中孔、中—低渗储层类型,储集性能良好,成岩作用处于中成岩阶段A1期。地层埋藏史、热演化史、烃源岩生烃史和成岩演化史的综合分析指示,储层孔隙空间的演化主要经历了机械压实减孔、早期胶结减孔、酸性溶蚀增孔和晚期胶结减孔4个阶段,其孔隙度的变化量分别为7.73%、4.61%、5.99%和2.54%,由此可建立储层孔隙定量演化的综合模式。受长期浅埋环境和成岩演化阶段影响,莱州湾凹陷沙河街组三段在古成藏期的储层孔隙度约为25%,油气充注情况良好。现今的孔隙类型仍以原生粒间孔为主,油气保存情况较好,勘探潜力较大。这一认识可为研究区的进一步勘探开发提供理论支持。

关键词: 孔隙定量演化, 成岩作用, 沙河街组三段, 莱州湾凹陷, 渤海湾盆地

Abstract:

The Laizhouwan sag, located in the southern part of the Bohai Bay Basin, is small but rich in hydrocarbons, and there is little research on reservoir diagenesis. The analysis results obtained by various technical means such as thin sections, SEM, X-ray diffraction, and cathodoluminescence show that the lithology of the middle-deep reservoirs in Member 3 of Shahejie Formation is mainly medium-fine grained lithic feldspar sandstone in the Laizhouwan sag, with medium-high compositional and textural maturity, good reservoir performance characterized by medium porosity and medium-low permeability, and at the stage A1 of mesodiagenesis. The comprehensive analysis of stratigraphic burial history, thermal evolution history, hydrocarbon generation history of source rocks and diagenetic evolution history indicates that the evolution of the reservoir pore spaces has mainly experienced four stages including mechanical compaction for porosity reduction, early cementation for porosity reduction, acidic dissolution for porosity increase and late cementation for porosity reduction, and the corresponding changes in porosity are 7.73%, 4.61%, 5.99% and 2.54%, respectively. On this basis, a comprehensive model of quantitative evolution of reservoir pores can be established. Affected by the long-term shallow burial environment and the diagenetic evolution stage, the porosity of ancient reservoir of Member 3 of Shahejie Formation in the Laizhouwan sag was ca. 25% in the accumulation period under good hydrocarbon charging conditions. At present, the pore type is still dominated by primary intergranular pores, showing good oil and gas preservation conditions and great exploration potentials. This understanding can provide theoretical support for further exploration and development in the study area.

Key words: quantitative pore evolution, diagenesis, Member 3 of Shahejie Formation, Laizhouwan sag, Bohai Bay Basin

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