水下碎屑流沉积特征、模式及石油地质意义——以渤海湾盆地东营凹陷为例

More and more debrites have been identified from deep-water deposition previously interpretated as turbidites after the first great upsurge in gravity flow research from 1960s to 1970s, which provides a chance to studying the sedimentary mechanism of subaqueous debris flow and relationships with others, and unfold a vigorous mass campaign for gravity flow deposits research. In this study, Dongying depression with a long history of hydrocarbon exploration and rich geological data for turbidite reservoirs was choosen as an example for studying for three types of depositional setting, i.e. steep-slope aprons, gentle-slope subwater fan and fluxoturbidite in the large delta front in a typical rift basin. Sedimentary mechanism, facies sequence model and facies architecture of subaqueous debris flow will be studied based on core observation, densed sampling and laboratory tests and experimental modelling restrained by geological conditions and standard vertical sedimentary profiles of three types. Firstly, classifications and sedimentary characteristics of subaqueous debris flow could be studied on the basis of cores and a great deal of eperimental data. Then, facies sequence models and dynamic analysis for every facies units would be discussed. Finally, depositional model dominated by subaqueous debris flow and its significance for hydrocarbon would be studied with 3D geological modelling for densed wells area. Some innovative progresses on classification scheme, identification marks, facies model and significance for hydrocarbon of subaqueous debrite and 3-4 SCI papers and 4-6 other papers must be achieved through this study.

继上世纪60-70年代重力流研究热潮之后，近年来在早期浊流理论解释的诸多深水沉积中识别出越来越多的碎屑流沉积，这为重新认识水下碎屑流识别标志、沉积机制及与其他沉积的组合关系提供了契机，掀起了重力流沉积研究新的热潮。选择"浊积岩"油气勘探历史悠久、资料丰富的东营凹陷为例，针对陡坡近源型、缓坡湖底扇型和长轴大型三角洲前缘滑塌型三类重力流沉积背景，以岩心观测及加密样品分析测试为基础，结合区域沉积、代表区标准沉积剖面解析和沉积物理模拟，开展水下碎屑流沉积机制、相序模式及空间分布规律研究。首先开展水下碎屑流成因类型细分并基于分类结果进行识别标志总结，然后结合物模结果建立水下碎屑流相序模式并进行动力机制解析，最后基于三维地质建模探索水下碎屑流主控的深水沉积发育模式及石油地质意义。预期在水下碎屑流分类方案与识别标志、相序模式与沉积机制、储层物性与含油性方面将取得创新性成果，发表SCI论文3-4篇，其他4-6篇。

继上世纪60-70年代重力流研究热潮之后，近年来在早期浊流理论解释的诸多深水沉积中越来越多地识别出碎屑流沉积，这为重新认识水下碎屑流沉积机制及与其他沉积的组合关系提供了契机。本次选择“浊积岩”油气勘探历史悠久、地质与地球物理资料丰富的渤海湾盆地济阳坳陷东营凹陷为例，以岩心观测及分析测试为基础，结合构造演化、物源供给、气候变化、湖平面升降等区域背景资料，开展湖泊沉积环境下水下碎屑流沉积沉积特征、沉积过程、相序模式及空间分布规律的研究工作。通过研究，取得如下研究结果：. （1）基于物质组成和沉积物支撑机制，新建了水下碎屑流细分方案。将水下碎屑流分为砂质碎屑流、泥质碎屑流和泥流。. （2）建立了水下碎屑流相序模式，并给出了动力机制解释。水下碎屑流沉积厚度普遍较大，自下而上一般由三个沉积单元组成：似平行层理段(pseudo-parallel division)（Da）、塞流块状层理段（plug flow massive division）（Db）和反递变层理段(inverse graded division)（Dc）。. （3）基于东营凹陷营11扇体的精细解剖，建立了水下碎屑流主控型湖底扇沉积模式。提出其基本沉积单元为砂质或泥质舌状体，基本构型样式为顺向前积、横向摆动，这与浊流主控型湖底扇中朵叶体为基本沉积单元，横向摆动的基础上侧向或垂向叠加的构型样式相区别。. （4）系统解剖了东营凹陷渐新世沙三中亚段滑塌型重力流沉积过程及沉积模式，建立了该区深水砂岩储层预测地质模型，开发了以相位调整和地层切片为核心的地质-地球物理相结合的薄层砂岩储层预测技术，油气勘探效益显著。. 4年以来，在水下碎屑流分类方案、识别标志、相序模式及其储层物性、含油性方面取得创新性成果，共发表科技论文12篇，其中SCI论文4篇。另有3篇稿件已被SCI期刊接受待刊。