东营凹陷泥页岩中碳酸盐成因及地质意义

Carbonate genesis and geological significance of shale in Dongying Sag

华彬 曾建强

成都理工大学沉积地质研究院，四川 成都 610059 成都理工大学油气藏地质及开发工程国家重点实验室，四川 成都 610059

Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu 610059, China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu 610059, China

利用岩心、薄片、扫描电镜、全岩矿物分析、元素分析、低温氮气吸附和工程力学性质等测试手段和分析资料，对东营凹陷沙河街组沙三下—沙四上湖相泥页岩中的碳酸盐成因及地质意义进行研究，将碳酸盐分为透镜状粗晶、透镜状微晶、纹层状微细晶、纹层状隐晶和块状隐晶等5种类型。透镜状粗晶碳酸盐为重结晶作用的产物，透镜状微晶碳酸盐为浊流搬运再沉积的产物，纹层状微细晶碳酸盐为藻类诱发碳酸盐沉淀的产物，纹层状隐晶碳酸盐为藻类诱发碳酸盐和钙质藻类残体共同形成的，滨浅湖的碳酸盐经重力流搬运至深湖形成块状隐晶碳酸盐。碳酸盐类型可以反映沉积环境变化和成岩演化阶段的不同，并能够改善泥页岩的储集性能。

Based on the data involving cores, thin sections, SEM, whole rock mineral components, elements, low temperature nitrogen adsorption and engineering mechanical properties, the genetic mechanism and geological significance of carbonate in the deep lacustrine shale of the lower submember of Member 3 and upper submember of Member 4 of Shahejie Formation were analyzed. It is considered that there are five kinds of carbonate developed in shale, including lenticular coarse crystalline, lenticular microcrystalline, lamellar micro-fine crystalline, lamellar cryptocrystalline and massive cryptocrystalline. The lenticular coarse crystalline carbonate was the product of diagenetic recrystallization. The lenticular cryptocrystalline carbonate was the product of turbidity transport and redeposition. The lamellar micro-fine crystalline carbonate was generated by algae induced carbonate precipitation. The lamellar cryptocrystalline carbonate was formed by algae inducing and calcareous algae residues. The carbonate from the shore-shallow lake was transported to the deep lake by gravity flow and formed the massive cryptocrystalline carbonate. Carbonate can reflect sedimentary environment and diagenetic evolution stage, and improve the reservoir performance.

10.6056/dkyqt201904010