Lake Sequence Stratigraphy of the Shahejie Formation in the Zhanhua Hollow, Shandong Province

Two sequences can be identified in the sedimentary strata of the lower Tertiary ShahejieFormation in the Zhanhua hollow. The lowstand, lake-transgressive and highstand systemstracts were formed under the control of ancient structure, palaeotopography, palaeoclimate, sed-iment supply, marine-transgression, and so on. In the paper the authors present a composite se-quence stratigraphical section of the Shahejie Formation in this area, and expound the bounda-ries of parasequences, parasequences set and systems tracts and evolutions of lake sequencestratigraphy and sedimentology and discuss various factors controlling the lake level fluctuation.The differences between lake and marine sequence stratigraphy are also indicated in the paper.The lake sequence stratigraphical study should be based on a synthetic analysis of structural evo-lution, palaeomagnetism, palaeoclimatic changes, geological Well logs, seismic and logging data,palaeontological data, global sea level changes, and so on. The sequence stratigraphical evolutionis closely related to the formation, development and elimination of the whole basin and thesedimentary process.     

山东沾化凹陷沙河街组湖泊层序地层研究

沾化凹陷下第三系沙河街组沉积地层可分成两个层序。在古构造、古地形、古气候、古物源供给及古海侵等因素控制下,层序内部发育了低水位体系域、湖侵体系域及高水位体系域。笔者建立了该地区沙河街组综合层序地层剖面,并针对体系域、准层序组及准层序界面的识别、湖泊层序地层及沉积演化等方面进行了详细阐述,讨论了控制湖平面升降的各种因素。文中表明了湖泊层序地层研究与海相层序地层研究之间的差异之处。湖泊层序地层研究必须基于构造演化、古地磁、古气候变迁、地质录井、地震及测井资料、古生物资料及全球海平面升降等资料的综合分析。层序地层演化与整个盆地的发育和消亡以及沉积演化之间有着密切的联系。     

山东东营凹陷东部深层浊积扇储层的微观特征及影响因素

东营凹陷东部深层浊积砂体以三角洲前缘的滑塌浊积砂体为主,储层岩性以长石细砂岩、岩屑细砂岩及粉砂岩为主,结构成熟度及成分成熟度均较低。储层微观特征研究表明,浊积砂体中主要发育剩余原生粒间孔、粘土矿物杂基内的微孔隙、粒间溶孔、粒内溶孔及微裂缝等储集空间类型;孔隙结构以低渗细喉型为主,为物性较差的中低孔、低渗型储层。通过对储层物性影响因素的研究得出,岩石组构、沉积微相、成岩作用和异常超压的形成与分布是影响本区浊积砂体储层物性的主要因素。其中成岩作用对浊积砂体物性的改造明显,压实和胶结作用是导致储层物性变差的主要原因;而溶蚀作用和成岩收缩作用则有利于储层孔渗性的改善。异常超压系统的存在、高的地温场及烃类的早期注入对该区浊积砂体储层物性起到了良好的保存和改善作用。     

苏北盆地溱潼凹陷断阶带油气运移路径综合分析

溱潼凹陷断阶带断裂系统发育,控制油气聚集的断层主要有F1、Ⅲ、F2、F3及其相应的分支断层,将断阶带分为北部的草舍扭动断裂带与南部的祝庄扭动断裂带。在断层封闭性定量评价与封闭史研究的基础上,结合研究区生排烃史、油源分布特征、油气成藏期以及含氮化合物示踪分析研究表明,断阶带Ⅲ、F2、F3断层在不同的研究区封闭性存在明显的差异,祝庄断阶带Ⅲ号断层垂向封闭性较好,不能成为油气运移的通道,使得角墩子地区的原油主要来源于阜四段源岩,没有阜二段与泰州组源岩的贡献;而F3断层活动期短,侧向封闭性差,也不为油气的运移通道;相比之下,F2断层活动期长,断层垂向封闭性差,而侧向封闭性好,为祝庄地区主要的运移通道,与油气成藏期具有较好的匹配关系,流体包裹体分布与含氮化合物示踪分析也证明了这一点。研究还表明草舍断阶带F2断层活动期短,垂向封闭性好,侧向封闭性弱,不是油气运移的通道;相比之下,F3断层活动期长,垂向封闭性较弱,可以作为油气运移的主要通道,后期主要通过砂体和不整合面运移聚集成藏,与生排烃史、油气成藏期和含氮化合物示踪也具有较好的匹配关系。     

Characteristics and controlling factors of reservoir space of mudstone and shale in Es3x in the Zhanhua Sag

Zhanhua Sag is a widely accepted target zone with huge exploration and development potential for shale oil and shale gas resources. Many detailed studies have been undertaken around the geochemistry of the lower section of the third member of the Shahejie Formation (Es3x), while few studies have focused on the reservoir. In this study, based on the mineralogical features and geochemical characteristics, and by using statistical methods, the characteristics and controlling factors of reservoir space of mudstone and shale in Es3x in the Zhanhua Sag are explored through field-emission scanning electron microscopy (FE-SEM), high pressure mercury injection capillary pressure (MICP), and nuclear magnetic resonance (NMR) techniques. Three major findings were obtained. ① There are micropores and microfractures in the reservoir space, which include intergranular pores, clay intercrystal pores, pyrite intercrystal pores, dissolved pores, structural microfractures, and bedding microfractures. ② According to the features of pore size distribution (PSD), the pore distribution can be divided into the following three categories: 0–50 nm, 50 nm–2 μm, and >2 μm; the average volumes of these components are 0.01079 mL g⁻¹, 0.00361 mL g⁻¹, and 0.00355 mL g⁻¹, respectively, thus showing that the pores whose radii are distributed at 0–50 nm form the most important reservoir space (though those with the 50 nm–2 μm and >2 μm radii are also important and cannot be ignored). ③ There are different controlling factors when it comes to different scale pores. Based on statistics and FE-SEM results, the dissolved pores in calcite were determined to be the controlling factor for the 0–50 nm portion, the intercrystalline pores in clay and pyrite, and intergranular pores between authigenic minerals (calcite, dolomite, and pyrite) and clastic minerals (calcite and dolomite) were determined to be the controlling factors for the 50 nm–2 μm portion, and the structural microfractures and bedding microfractures were determined to be the main factors for the >2 μm portion. Furthermore, it is the brittle minerals content and bedded structure that control the microfractures. This study thus clarifies the types and characteristics of reservoir space and identifies pore structure controlling factors of mudstone and shale in Es3x in the Zhanhua Sag; this information has important significance for future reservoir evaluations.     

山东沾化滨海地区浅层地下卤水矿层特征及形成条件

山东沾化滨海地区地下卤水为古浓缩海水封存而成。浅层地下卤水主要赋存在40 m深度以上的粉砂和粉土层中,垂向上分为2个矿层,总厚度9.9-33.7 m,矿化度50.0-99.7 g/L,水位埋深1.2-4.3 m,单位出水量10.42-58.94 m3/（d.m）,富水性中等,动态较为稳定。卤水开发利用应合理规划,避免资源浪费,注重综合利用和环境保护。     

沾化凹陷复式生烃系统及其对油气成藏的控制作用

陆相断陷盆地油气勘探实践证明,丰富的油气资源与富含有机质的生烃洼陷具有十分密切的关系。陆相断陷湖盆多沉降中心、多物源和充填演化的多旋回性,形成了多套生油层系和多种油气储集相带组合,并在空间上形成了多个含油气系统。油源对比表明沾化油区存在5种不同地球化学特征的原油,常形成“一源多藏”和“多源一藏”的单源或混源组合特点,它们分别来自沙四上段烃源岩、沙三段烃源岩、沙一段烃源岩,以及来自沙四上段与沙三段混源和来自沙三段与沙一段混合。由不同地球化学特征的烃源岩层组成的复式生烃系统所形成的油气藏在空间分布上具有一定的规律性。复式生烃系统的特点控制了复合含油气系统的形成和分布。     

网毯式油气成藏体系仓储层运移机理研究

研究网毯式油气成藏体系仓储层运移油的机理,揭示断层幕式排烃期仓储层运移油的机理,以油气二次运移理论为指导,开展了油沿断裂纵向运移及油在仓储层内横向运移的定量研究.首先根据地质模型,建立断层内油压力衰减梯度的数学模型,根据能量守恒原理,推导出油沿断层纵向运移的压力梯度公式,计算出油沿断裂进入仓储层的初始压力,再根据仓储层的地质模型,建立油在仓储层内横向运移的压力衰减模型及上网层开启时的泄压模型,推导出油沿仓储层横向运移的压力梯度公式及泄压公式,最终得出仓储层运移油的合力公式.并指出当运移动力大于运移阻力,即运移合力为正时,仓储层以运移油为主,当运移动力等于或小于运移阻力,即运移合力为负时,仓储层以临时仓储(成毯)、成藏为主.通过对运移合力的计算,可以判断油在仓储层内运移、成毯和成藏的状态,预测仓储层运移、成毯或成藏的范围,从而指导该体系隐蔽油气藏的勘探.     

济阳坳陷沾化凹陷古近系水化学场对湖盆演化的响应及其油气意义*

通过对沾化凹陷古近系1160条数据体的试油资料、原油物性资料的分析,对沾化凹陷古近系沙河街组四段到东营组的水化学场特征进行了研究,结果表明：沾化凹陷古近系水化学场分布特征与湖盆演化的旋回性有良好对应关系,从湖盆的断陷初期阶段到断陷鼎盛阶段（沙河街组四段到三段）,湖盆水体加深及淡化,矿化度及氯离子含量平均值逐渐下降;而在湖盆的总体萎缩阶段（从沙河街组二段到东营组沉积期）,水体总体变浅,矿化度及氯离子含量平均值总体增大。在各阶段,地层水类型均以NaHCO₃型占绝对优势（比例达到80％）,显示了典型的开放型湖盆的地层水场特征。NaHCO₃型地层水主要分布于地层水矿化度较低（<15 g/L）的地层中,指示了水交替活动强烈的开放水文环境,对油气保存不利;而相对较高矿化度（≥15 g/L）的NaHCO₃型地层水主要分布于生烃洼陷（渤南洼陷等）内部及义东断裂构造带附近,其成因主要与油气田形成和高含量的、以深部幔源为主的CO₂气及断裂沟通有关,其对应的原油密度基本小于0.9 g/mL,指示了相对有利的油气保存环境。     

南海西南次海盆构造特征及其沉积响应

本文对穿过南海西南次海盆的逾1000 km的多道地震测线CFT剖面进行了地震界面特征的识别和地震层序的划分,分段分析了拆离断层对其减薄陆壳的拆离作用。结合前人研究成果,对南海西南次海盆地壳结构特征开展了分析,并总结了其构造特征。西南次海盆在发生陆缘张裂—海盆扩张、洋壳出现—扩张后稳定沉积这一系列过程中,可划分为4个阶段的沉积响应：A阶段(古新世之前)——前裂谷阶段,表现为地壳在拉张应力下产生小的断层;B阶段（始新世—早渐新世）——陆缘的裂谷阶段,地壳在拉张应力下拉张减薄,A阶段产生的断层出现了旋转,出现了大型掀斜的拆离断层,沉积物为同裂谷沉积,该阶段以产生了破裂不整合结束;C阶段（晚渐新世—早中新世）——海盆扩张阶段,海盆开始扩张,张应力从陆缘转移到了洋盆;D阶段（中中新世以来）——海盆扩张结束以后,以一套稳定沉积为特征。