“组分混合”沉积的储层非均质性及形成机理——以渤海海域古近系沙河街组一、二段为例  

Characteristics and Formation Mechanism of Heterogeneity in“Compositional Mixing”Reservoirs:An example from the First-Second member of the Palaeogene Shahejie Formation,Bohai Sea

作　　者：叶茂松 解习农 杜学斌 赵珂 吴峰 YE MaoSong;XIE XiNong;DU XueBin;ZHAO Ke;WU Feng(Marine Engineering Department,Hainan Academy of Ocean and Fisheries Sciences,Haikou 571126,China;College of Marine Science and Technology,China University of Geosciences(Wuhan),Wuhan 430074,China;School of Earth Resources,China University of Geosciences(Wuhan),Wuhan 430074,China;College of Oceanography,Hohai University,Nanjing 210098,China)

机构地区：[1]海南省海洋与渔业科学院海洋工程所,海口571126 [2]中国地质大学(武汉)海洋学院,武汉430074 [3]中国地质大学(武汉)资源学院,武汉430074 [4]河海大学海洋学院,南京210098

出　　处：《沉积学报》2025年第2期635-652,共18页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(42106058);海南省近岸海洋生态环境过程与碳汇重点实验室开放基金项目(2022RHDKFKT07)。

摘　　要：【目的】混合沉积储层是具有重要勘探潜力的油气储层类型,但存在极强的非均质性。前人对“层系混合”型储层的非均质性问题开展了诸多探索,然而对“组分型混合”沉积储层却缺少系统认识。近年来,渤海海域中—深层古近纪地层发现典型的“组分混合”沉积并在其中获得了重大油气突破,这为探讨此类储层非均质性的成因机理提供了理想的研究材料。【方法】利用渤海海域丰富的钻井资料,系统开展了“组分混合”沉积非均质性特征与成因机制的研究。【结果】研究区“组分混合”沉积的储层类型包括原生生物混积滩和混积型碎屑流块体。不同储层类型组分特征和空间分布上具有显著差异,这受控于不同因素影响:受古气候与物源影响,原生生物混积滩易分布于碎屑沉积侧翼或构造高部位;湖平面变化控制不同成因相的叠置差异。混积型碎屑流块体受古地貌与水深的约束,主要分布于凸起斜坡近端;水动力差异导致成因相垂向样式的频繁变化。其次,两类储层均呈现复杂的储层物性与孔隙结构非均质性,主要受陆源碎屑组分、选择性溶蚀量、白云岩化、胶结物产状与数量等因素的综合影响。【结论】构建的“组分混合”沉积的储层非均质性形成模式对混合沉积的分布预测与有利储层评价具有重要的启示意义。[Objective]Mixed siliciclastic-carbonate reservoirs are a new target reservoir for hydrocarbon exploration;however,the heterogeneities can lead to unanswered questions.Previous studies have focused on“strata mixing”sediments,with little attention giben to the“compositional mixing”type.In recent years,typical“compositional mixing”sedimentation has been discovered in medium-deep Paleogene deposits in the Bohai Sea with breakthroughs in oil and gas exploration,providing an ideal case to explore the heterogeneity within“compositional mixing”deposits.[Methods]Abundant drilling data were used for detailed studies on the characteristics and main controlling factors of the heterogeneities associated with“compositional mixing”[.Results]Two principal reservoir types were recognized in this study:biological and debris-flows mixing shores.The two types have significant heterogeneities in petrofabric and spatial distribution owing to a complex interplay of controlling factors.The biological mixing shore reservoir is distributed in the flanks of detrital deposition and/or a higher position of structural units t\controlled by paleoclimate.Lake-level changes influence the vertical stacking of different genetic facies within this reservoir type..The debris-flows mixing shoal reservoir has later distribution on the proximal area of nearby uplift because this type can be controlled by the interplay of paleoclimate and paleo water-depth.Furthermore,the vertical patterns are heterolithic and are related to the variational hydrodynamic strength of gravity-driven depositional processes.The complex heterogeneity of the reservoir physical properties and pore structure is attributed to the mutual influence of clastic components supply,selective dissolution,dolomitization,cement type,and quantity.[Conclusions]Finally,a formation model of“compositional mixing”heterogeneity was developed,with significance for the further reservoir prediction and evaluation of worldwide mixed sediments reservoirs.

关 键 词：组分混合储层 非均质性 沉积分布 储集性能 沙河街组 渤海海域 

分 类 号：P618.13[天文地球—矿床学]