东营凹陷古近系湖相细粒混积岩沉积成岩特征

东营凹陷古近系湖相细粒混合沉积岩相类型、沉积环境和成岩演化等方面有待深入研究，利用岩心观察、薄片、X衍射和碳氧同位素等分析手段，明确了细粒混积岩相类型和沉积成岩特征.研究认为:岩石矿物组分和古生物含量的纵向变化较好地反映了沉积环境的变化和混合沉积成因过程，可作为细粒沉积层序四级界面识别标志.泥晶和亮晶方解石经历过显著的碳氧同位素分馏，证实了混积岩中泥晶方解石主要隶属于与甲烷细菌活动生成生物气有关的碳酸盐，透镜状和纹层状亮晶方解石纹层源自脉体方解石充填微裂缝，微裂缝和方解石脉集中形成于早期次干气-生油阶段.阐述了从生烃增压、微裂缝形成、有机质热演化排出有机酸、溶蚀泥晶方解石、方解石重结晶和脉体形成，直至影响临近砂体胶结作用的整个同生演化过程，对中深层页岩油气成藏研究具有重要指导意义. 

Sedimentary and Diagenetic Characteristics of Lacustrine Fine-Grained Hybrid Rock in Paleogene Formation in Dongying Sag

It needs further study on Paleogene lacustrine fine-grained hybrid sedimentary lithofacies type, carbonate isotopic fractionation mechanism and diagenetic evolution in Dongying sag. By core observation, thin section, X-ray diffraction, carbon and oxygen isotopes and other analytical methods, it is considered to be a fine-grained in-situ mixed sedimentary rock, which can be divided into four types of lithofacies:felsic fine-grained hybrid rock and clayey fine-grained hybrid rock, carbonate fine-grained and clayey felsic fine-grained hybrid rock. The analysis of "genetic control layer" shows that the vertical changes of rock mineral composition and paleontological content reflect the supply of source, paleoclimate fluctuation and sedimentary process, which can be used as the identification mark of sequence boundary. Carbon and oxygen isotopic analysis shows that micrite calcite mainly belongs to carbonate related to biogenic gas generated by methane bacteria activity, lenticular and lamellar sparry calcite layers belong to the phenomenon of microcracks being filled by calcite veins, the general buried depth of microcracks and calcite vein formation are the early secondary dry gas generation stage, and sandstone calcite cement is closely related to the generation of mixed vein body. It is further revealed the isotopic fractionation mechanism of micrite and sparry calcite in migmatite, and the whole coevolution process from hydrocarbon generation pressurization, microfracture formation, organic matter thermal evolution to organic acid expulsion, dissolution micrite calcite and calcite recrystallization to calcite vein, which has important guiding significance for the study of shale oil and gas accumulation in middle and deep oil reservoir.