湖相泥页岩中碳酸盐成因及页岩油气地质意义——以东营凹陷沙河街组四段上亚段—沙河街组三段下亚段烃源岩为例

发布时间：2018-05-15 00:06

本文选题：碳酸盐 + 成因机理　；参考：《石油学报》2017年12期

【摘要】：利用岩心、薄片、全岩矿物组分、元素、同位素等资料,对东营凹陷沙河街组四段上亚段—沙河街组三段下亚段深湖相烃源岩中碳酸盐成因机理进行了研究,认为深湖主要发育透镜状粗晶、纹层状微细晶、纹层状隐晶和块状隐晶4种类型碳酸盐。其中,透镜状粗晶碳酸盐为成岩重结晶的产物;纹层状微细晶碳酸盐和纹层状隐晶碳酸盐为藻类光合作用不断从水中萃取CO_2,导致水体CO_3~(2-)浓度升高,与湖水表层携带的Ca~(2+)相互作用的产物,咸水环境有利于碳酸盐晶粒保存,碳酸盐多呈微细晶纹层状分布,微咸水环境水体较深,碳酸盐晶粒在碳酸盐补偿深度面以下通常会发生溶蚀,大多呈隐晶纹层状保存下来;块状隐晶碳酸盐是浅水地带沉积碳酸盐由重力流搬运至深水地带的产物。碳酸盐一定程度上控制了东营凹陷沙河街组四段上亚段—沙河街组三段下亚段泥页岩的储集性和可压性,也将为古湖泊沉积环境恢复提供重要信息。
[Abstract]:Based on the data of core, thin slice, mineral components, elements and isotopes of whole rock, the mechanism of carbonate genesis in deep lacustrine source rocks of the fourth member of Shahejie formation in Dongying Sag and the lower part of the third member of Shahejie formation is studied. It is considered that four types of carbonate are mainly developed in the deep lake, which are lenticular coarse crystal, lamellar fine grain, lamellar cryptic grain and block cryptic crystal. Among them, lenticular coarse crystalline carbonate is the product of diagenetic recrystallization, and lamellar microcrystalline carbonate and lamellar cryptosectic carbonate are algae photosynthesis, which continuously extract CO _ 2 from water, resulting in the increase of water CO _ 3O _ 3 ~ (2) concentration. The product of interaction with Ca~(2) in the surface layer of lake water, salt water environment is favorable for the preservation of carbonate grain, carbonate is mostly distributed in fine grained layer, and the water body is deep in brackish water environment. Carbonate grains usually dissolve below the depth of carbonate compensation, most of them are preserved in cryptmorphic layers, and massive cryptocrystalline carbonate is the product of sedimentary carbonate transported from gravity current to deep water zone in shallow water zone. To some extent, carbonate controls the reservoir and compressibility of shale from the upper submember of the fourth member of Shahejie formation to the third member of Shahejie formation in Dongying Sag, which will also provide important information for the restoration of sedimentary environment of palaeolake.
【作者单位】：中国石油化工股份有限公司胜利油田分公司勘探开发研究院;中国石油化工股份有限公司胜利油田分公司;
【基金】：国家重点基础研究发展计划(973)项目(2014CB239100)资助
【分类号】：P618.13

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