【摘要】 为解决苏北盆地高邮凹陷古近系阜宁组二段(阜二段)页岩油富集主控因素不清、优势“甜点”预测难度大等问题，采用岩心观察、薄片鉴定、X线衍射矿物分析、有机地球化学测试、扫描电镜观察、低温气体吸附、高压压汞及核磁共振等实验方法，开展岩相类型划分、孔隙结构表征、含油性及可动性评价，分析不同岩相组合的储集性能、生烃潜力、含油饱和度及可压性，进行典型岩相组合样品的全息扫描荧光与热解参数测试，研究不同岩相组合对页岩油富集与可动性的控油作用，明确差异含油性特征和富集模式。结果表明，研究区发育混积页岩、灰云质页岩、长英质页岩及黏土质页岩四类岩相，构成纯混积页岩、混积页岩夹灰云质页岩及混积页岩夹长英质页岩三种优势组合。混积页岩夹灰云质页岩组合的灰云质页岩夹层发育溶蚀孔，具有三峰式孔隙结构，孔喉连通性好，脆性指数高，表现最强的游离烃富集能力与可动性，是页岩油富集的“甜点”层段；混积页岩基质生烃潜力优越但可动性中等，主要作为烃源供给与原位储集体；长英质页岩微孔发育、排驱压力高而形成有效封隔屏障。陆相页岩油富集模式以“甜点夹层(灰云质页岩)主导富集、烃源基质(混积页岩)支持成藏、致密夹层(长英质页岩)封隔保存”为核心。该结果为苏北盆地及类似地质条件下的页岩油勘探提供指导。更多还原

【Abstract】 This study was undertaken to address the limited understanding of the primary controls on shale oil enrichment and the challenges in predicting high-quality "sweet spot" intervals within the second member of the Paleogene Funing Formation（E₁f₂） in the Gaoyou Sag,Subei Basin.The aims of this paper are to reveal the controlling mechanisms of different lithofacies assemblages on shale oil enrichment and mobility,clarify the characteristics of differential oil-bearing properties in the area,and ultimately establish an enrichment model to guide exploration deployment.Focusing on the E₁f₂ shale in the Gaoyou Sag,we comprehensively employed an integrated experimental methodology including core observation,thin-section identification,X-ray diffraction（XRD） mineral analysis,organic geochemical testing,scanning electron microscopy（SEM）,low-temperature gas E₁f₂ adsorption,high-pressure mercury intrusion porosimetry（MIP）,and nuclear magnetic resonance（NMR）.This integrated approach enabled systematic lithofacies classification,pore structure characterization,and evaluation of oil-bearing potential and hydrocarbon mobility.Building on this,we focused on analyzing the reservoir properties,hydrocarbon generation potential,oil saturation,and fracturability of different lithofacies assemblages.The oil-controlling effect of lithofacies assemblages was empirically verified through coupled Total Scanning Fluorescence（TSF） and pyrolysis parameter analysis on samples from typical assemblages.The research identifies four main lithofacies in the study area:mixed shale,calcareous-dolomitic shale,felsic shale,and argillaceous shale,which form three dominant assemblages,namely Pure Mixed Shale,Mixed Shale Intercalated with Calcareous-Dolomitic Shale,and Mixed Shale Intercalated with Felsic Shale.Among these,the Mixed Shale Intercalated with Calcareous-Dolomitic Shale assemblage,due to its calcareous-dolomitic interlayers featuring dissolved pores,a trimodal pore structure,excellent porethroat connectivity,and high brittleness index,exhibits the strongest free hydrocarbon enrichment capacity and mobility,representing the "sweet spot" interval for shale oil enrichment.The mixed shale matrix possesses superior hydrocarbon generation potential but moderate mobility,primarily acting as the hydrocarbon source and in-situ storage unit.The felsic shale,characterized by well-developed micropores and high displacement pressure,acts as an effective sealing barrier.This study establishes a continental shale oil enrichment result centered on the concept of "Enrichment dominated by sweet spot interlayers（Calcareous-Dolomitic Shale）,accumulation supported by hydrocarbon-prone matrix（Mixed Shale）,and preservation sealed by tight interlayers（Felsic Shale） ".This result provides significant theoretical guidance for shale oil exploration in the Subei Basin and analogous geological settings.更多还原