济阳坳陷古近系孔店组旋回沉积机理及成岩系统研究

It is a hot issue of oil and gas exploration to the reservoir research of kongdian formation of Paleogene in Jiyang depression,The cyclic sedimentation and diagenetic system of kongdian formation is one of the key issues to address oil and gas exploration,The existing information is mainly limited to the qualitative description of sedimentary facies and sequence stratigraphy of the lack of knowledge on the relationship between the Kongdian cyclic deposition mechanism and the diagenetic system, the lack of a comprehensive study of the deposition - diagenetic system.Take the deep-kongdian formation in jiyang drpression for the object of study,the subject focus on analysis of the material coupling relationship between the Kongdian stratigraphic cycles sedimentary and diagenetic systems.This study will take a sequence stratigraphy, sedimentology, diagenesis, and other multi-disciplinary, combining macro and micro, the main use of drill logging data, thin section, scanning electron microscopy, fluid inclusions, trace elements, REE, stable isotopesmethod,which will research the cyclic sedimentation style to investigate material distribution methods and deposition mechanism of the cyclic sedimentation;which will research the diagenesis and evolution to investigate the diagenetic systems and their influencing factors;which will resrtore the original deposition material gathered and modes of distribution of the today's rock which transformed by multi-stage diagenetic fluid,explore the material coupling between cycles of sedimentary and diagenetic systems.The above study will provide a theoretical reference for knowing Kongdian stratum-cyclic sedimentation mechanism and the diagenetic evolution system, will also provide a new theoretical basis for the relationship between sequence and diagenesis of clastic rock.

济阳坳陷古近系孔店组深层储层研究成为油气勘探的热点问题，孔店组旋回沉积和成岩系统研究是解决油气勘探的关键问题之一，现有的资料主要限于对沉积相及层序地层进行定性描述，对孔店组旋回沉积机理以及与成岩系统的关系认识不足，缺少沉积-成岩系统综合研究。本课题以济阳坳陷深层孔店组为研究对象，重点分析孔店组地层旋回沉积与成岩系统的物质耦合关系。本研究将采取层序地层学、沉积学、成岩学等多学科综合，宏观与微观相结合，主要利用钻测井资料、岩石薄片、扫描电镜、流体包裹体、微量元素、稀土元素、稳定同位素等方法，研究旋回沉积样式，探讨旋回沉积的物质配分方式和发生机理；研究成岩作用及演化，探讨成岩系统及其影响因素；恢复多期次成岩流体改造下当今岩石的原始沉积物质聚集和配分方式，探讨旋回沉积与成岩系统的物质耦合关系。上述研究将为认识孔店组旋回沉积-成岩演化系统提供理论借鉴，也将为碎屑岩层序-成岩关系研究提供新的理论依据。

本项目按照研究计划，主要利用了钻测井资料、岩石薄片、扫描电镜、流体包裹体、微量元素、稀土元素、稳定同位素等方法，系统研究了济阳断陷湖盆环境演化规律和物质分异作用；查明了孔店组岩性地层旋回和颜色旋回的叠加方式、物质响应及聚集规律、旋回沉积作用的控制因素和动力机制；系统总结了孔店组成岩作用类型、典型矿物特征、成岩演化阶段和演化过程；探讨了旋回沉积记录下的成岩响应特征、物质耦合关系及成岩系统相关问题。. 研究结果表明，济阳断陷湖盆早期经历了多旋回的演化过程，湖盆中碎屑物质和化学物质的分异作用同时发生，空间上分为粗碎屑沉积、化学沉积、混合沉积和机械沉积等4个沉积区，该时期湖水为逐渐咸化的盐湖环境，具有空间的分带性和时间的阶段演化性；旋回沉积记录包括颜色米级旋回、粒序米级旋回和非粒序米级旋回，该差值与古近纪超短期旋回、短期旋回和中期旋回的时间差基本一致，证实了孔店组湖泊相旋回沉积受控于米兰科维奇旋回。除此之外，旋回发育时期的古气候、沉积水介质的共轭震荡、物质供应等沉积动力因素也影响了旋回的发育过程。典型成岩现象有强烈压实作用、硬石膏胶结、多期次碳酸盐胶结、多期次粘土矿物胶结、硅质强烈胶结、矿物强烈穿插交代、碎屑颗粒和胶结物的溶解作用，成岩演化经历了准同生期-中成岩B期，部分达到晚成岩期的演化过程，讨论了原始干旱-半干旱沉积环境、基准面变化、深埋藏环境、构造-岩浆活动是控制成岩及孔隙演化的主要因素；砂-泥互层沉积体系组成封闭性的成岩系统，泥岩成岩过程的早期压实排水和差异压实作用、中晚期粘土矿物转化、结构水和有机酸的排放制约砂岩层的成岩作用，而砂-泥混合岩封闭成岩系统主要跟碎屑岩的结构成熟度有关。旋回变化与元素的耦合关系主要跟岩性和成岩系统封闭性有关，砂岩耦合性较差、泥岩耦合性较好，开放系统耦合性较差，封闭系统耦合性较好。