胡平,殷杰,王振奇,等.苏北盆地高邮凹陷古近系戴南组一段成岩作用与成岩相[J].河南理工大学学报(自然科学版)，doi: 10.16186/j.cnki.1673-9787.2025120096.

HU P, YIN J, WANG Z Q, et al． Diagenetic and diagenetic facies in the first member of Dainan Formation of the Paleogene in Gaoyou Sag, Subei Basin[J]. Journal of Henan Polytechnic University( Natural Science) ， doi: 10.16186/j.cnki.1673-9787.2025120096.

苏北盆地高邮凹陷古近系戴南组一段成岩作用与成岩相

胡平，殷杰，王振奇，吴楠，叶琳，段明杨

长江大学 地球科学学院，湖北 武汉 430100

摘要: 目的 为阐明非均质性储层的成因机制和孔隙演化路径，探讨基于定量成岩参数与沉积微相的成岩相分布。 方法 以苏北盆地高邮凹陷古近系戴南组一段为研究对象，综合利用岩石薄片鉴定、Ｘ射线衍射、扫描电子显微镜、高压压汞、核磁共振等实验手段，系统分析储层特征和成岩作用。 结果 结果表明，戴一段储集空间以残余原生孔和粒内溶孔为主，次为粒间溶孔和裂缝，吼道连通性较差，为微米级孔隙和亚微米级喉道组合；主要经历了早成岩B期压实胶结、中成岩A1亚期溶蚀与A2亚期晚期胶结3个演化阶段,目前正处于中成岩阶段A-B期，机械压实和早期方解石胶结破坏大量原生孔隙，是储层变差的主要原因，长石和不稳定岩屑溶蚀形成次生溶蚀，对于改善储集层物性具有建设性意义；戴一段划分为4类成岩相，弱压实-弱溶蚀相和中压实-中溶蚀相物性较好，主要发育于三角洲前缘与扇三角洲前缘水下分流河道微相，为研究区有利储层，中压实-碳酸盐胶结相和强压实-黏土矿物胶结相基本无储集性能。 结论 戴一段储层是典型“先天欠缺、后期改造”储层。优质储层的发育经历了“有利沉积相带奠基、早期弱破坏保存、中期溶蚀改造”过程，未来勘探应聚焦于弱压实-弱溶蚀相与中压实-中溶蚀相成岩相的空间展布规律，为油气勘探和开发提供地质依据。

关键词:储层特征；成岩作用；成岩相；古近系；戴一段；高邮凹陷

doi: 10.16186/j.cnki.1673-9787.2025120096

基金项目:国家自然科学基金资助项目（41402111）

收稿日期：2025-12-29

修回日期：2026-04-21

网络首发日期：2026-07-06

Diagenetic and diagenetic facies in the first member of Dainan Formation of the Paleogene in Gaoyou Sag, Subei Basin (Online)

Hu Ping, Yin Jie, Wang Zhenqi, Wu Nan, Ye Lin, Duan Mingyang

School of Geosciences, Yangtze University, Wuhan 430100,Hubei,China

Abstract: Objectives This study aims to elucidate the genetic mechanisms and porosity evolution pathways of heterogeneous reservoirs, and to investigate the distribution of diagenetic facies based on quantitative diagenetic parameters and sedimentary microfacies. Methods Taking the first member of the Paleogene Dainan Formation (E₂d₁) in the Gaoyou Sag of the Subei Basin as the research object, this study comprehensively employs thin-section petrography, X-ray diffraction (XRD), scanning electron microscopy (SEM), high-pressure mercury intrusion porosimetry (HPMIP), and nuclear magnetic resonance (NMR) to systematically characterize reservoir properties and diagenetic processes. Results The reservoir space of the E₂d₁ is dominated by residual primary pores and intragranular dissolution pores, with secondary intergranular dissolution pores and fractures. The pore-throat connectivity is relatively poor, characterized by a combination of micrometer-scale pores and sub-micrometer throats. The reservoir primarily underwent three evolutionary stages: compaction and cementation in the early diagenetic stage B, dissolution in the middle diagenetic stage A1 sub-stage, and late cementation in the A2 sub-stage. It is currently in the transition from middle diagenetic stage A to B. Mechanical compaction and early calcite cementation destroyed a significant amount of primary porosity, which is the main reason for reservoir quality degradation. The dissolution of feldspar and unstable lithic fragments created secondary porosity, playing a constructive role in improving reservoir properties. The E₂d₁ can be classified into four diagenetic facies. The weakly compacted-weakly dissolved facies and moderately compactied-medium dissolved facies exhibit better physical properties and are mainly developed in underwater distributary channels within delta front and fan-delta front microfacies, representing favorable reservoirs in the study area. The moderately compacted-carbonate cemented facies and strongly compacted-clay mineral cemented facies essentially possess no reservoir potential. Conclusions The E₂d₁ reservoir is a typical "poor initial endowment, modified later" type. The development of high-quality reservoirs followed a process of "foundation by favorable sedimentary facies, preservation through early weak destruction, and modification by mid-term dissolution." Future exploration should focus on the spatial distribution patterns of the weak compaction-weak dissolution and medium compaction-medium dissolution diagenetic facies to provide a geological basis for oil and gas exploration and development.

Keywords: reservoir characteristics; diagenesis; diagenetic facies; Paleogene;E₂d₁; Gaoyou Sag