页岩层序划分的界面沉积标志及地球化学指示

发布时间：2018-09-03 12:41

【摘要】：页岩油气勘探需解决的一个基础核心问题是建立富有机质页岩高精度岩相层序,准确预测页岩甜点段。受页岩沉积相对连续与特征变化难识别等因素控制,页岩地层层序关键界面识别难度较大。文章通过国内外文献调研,结合北美和国内部分页岩沉积储层实例特征,指出在页岩沉积中的相对较浅区域,小型冲刷面、低角度的页岩层断面、软质沉积物变形、壳质纹层和冲断构造碎屑等沉积特征的出现是层序边界的重要沉积学指示。对应等时地层中未出现以上明显剥蚀面的连续页岩层沉积,岩相组合转换面、不同类型滞留沉积物、黄铁矿鲕粒层或磷酸盐结核面,加之配合指示氧化-还原条件(有机地化参数、无机微量/主量元素等)及有机物/矿物富集变化规律(有机质丰度、沉积物密度、矿物成分含量等)的地球化学指标可综合判断层序边界或最大海泛面。文章结合国内外实例,详细总结梳理了在测井资料辅助下,使用沉积学特征和地球化学参数分析判断层序界面的关键问题和理论解释,提倡在页岩层序地层划分中,利用钻测井曲线和岩相组合划分三级层序,并结合使用沉积特征和地球化学参数准确搭建四级及以上高频层序格架。
[Abstract]:One of the core problems to be solved in shale oil and gas exploration is to establish high-precision lithofacies sequence of oil-rich shale and accurately predict shale desserts. It is difficult to identify the key interface of shale stratigraphic sequence controlled by the relative continuity of shale deposition and the difficulty of identifying the characteristics of shale stratigraphic sequence. Based on the domestic and foreign literature, combined with the characteristics of some shale sedimentary reservoirs in North America and China, the paper points out that relatively shallow area, small scour surface, low angle shale section and soft sediment deformation in shale deposition. The appearance of sedimentary features such as crustaceous grain and thrust tectonic clastic is an important sedimentological indication of sequence boundary. Corresponding to isochronous strata, there are no continuous shale deposits with obvious denudation surfaces above, lithofacies assemblage transfer surfaces, different types of retained sediments, pyrite oolitic beds or phosphate nodule surfaces, In addition, the combination indicates the oxidation-reduction conditions (organic geochemistry parameters, inorganic trace / principal elements, etc.) and the enrichment and variation of organic matter / minerals (organic matter abundance, sediment density, etc.), The geochemical index of mineral composition can be used to judge the sequence boundary or the maximum sea surface. Combined with examples at home and abroad, this paper summarizes and combs the key problems and theoretical explanations of sequence interface analysis by means of sedimentological characteristics and geochemical parameters under the aid of logging data, and advocates the division of the sequence stratigraphy in the page rock. The third order sequence is divided by drilling log curve and lithofacies combination, combined with sedimentary characteristics and geochemical parameters, the high frequency sequence framework of four grades and above is built accurately.
【作者单位】：中国石油大学(北京)油气资源与探测国家重点实验室;中国石油大学(北京)非常规天然气研究院;中国石化胜利油田分公司西部新区研究院;中国石油尼罗河公司;中海油研究院;
【基金】：中国石油大学(北京)科研基金项目(2462017YJRC009) 国家科技重大专项(2007ZX05035) 国家自然科学基金重大项目(41690133)
【分类号】：P618.13

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