渤海湾盆地东营凹陷古近系富碳酸盐矿物页岩储集特征及其控制因素

Reservoir characteristics and controlling factors of Paleogene carbonate-rich shale in Dongying Sag, Bohai Bay Basin

徐效平

XU Xiaoping

中国石化 胜利油田 东胜精攻石油开发集团股份有限公司, 山东 东营 257000

Dongsheng Jinggong Petroleum Development Stock Co., Ltd., Shengli Oilfield, SINOPEC, Dongying, Shandong 257000, China

综合运用岩心观察、薄片观察、氮气吸附和X衍射等分析方法，对渤海湾盆地济阳坳陷东营凹陷牛页1井、樊页平1井古近系沙河街组四段上亚段的湖相页岩的矿物组成、沉积构造、纹层类型、孔径分布、孔体积、比表面积、纹层数量及溶蚀孔形态等特征进行了精细刻画。在此基础上总结了该地区主要岩相类型及纹层特征，不同岩相的孔径、孔体积及比表面积，富碳酸盐矿物页岩的孔隙及纹层特征。东营凹陷主要发育富有机质纹层状泥质灰岩、富有机质纹层状砂质灰岩、含有机质纹层状砂质灰岩、含有机质块状灰岩4种岩相类型。纹层镜下特征主要有平直状、透镜状、夹层状、波状等特征。实测氮气吸附数据显示东营凹陷富碳酸盐矿物页岩具有更大的孔体积及比表面积。同时，溶蚀孔和纹层的发育使得富碳酸盐矿物页岩具有更高的储集能力和水平渗透率。因此，富碳酸盐矿物页岩是东营凹陷优质储集单位。

In this paper, the mineralogical composition, sedimentary structure, laminar type, pore size distribution, pore volume, specific surface area, number of laminae and morphological characteristics of dissolution pores of the lacustrine shale from the upper sub-member of the fourth member of the Paleogene Shahejie Formation of the wells NY1 and FYP1 in the Dongying Sag of Bohai Bay Basin were finely characterized by a combination of core observation, thin section observation, nitrogen adsorption and X-ray diffraction. On this basis, the main lithofacies types and laminar characteristics, the pore size, pore volume and specific surface area of different lithofacies, and the pore and laminar characteristics of carbonate-rich shale in this area were summarized. The results show that there are four lithofacies types in the Dongying Sag: organic-rich laminated argillaceous limestone, organic-rich laminated sandy limestone, organic-bearing laminated sandy limestone and organic-bearing massive limestone. The microscopic features of the laminae are mainly flat, lenticular, interbedded and undulating. The measured nitrogen adsorption data show that the carbonate-rich shale in the Dongying Sag has a larger pore volume and specific surface area. At the same time, the development of dissolution pores and laminae allows the carbonate-rich shale to have higher storage capacity and horizontal permeability. Therefore, the carbonate-rich shale is a high quality reservoir in the Dongying Sag.

https://doi.org/10.11781/sysydz202303413