渤海湾盆地沾化凹陷沙河街组富有机质页岩孔隙分类及孔径定量表征  

Classification and quantitative characterization of microscopic pores in organic-rich shale of the Shahejie Formation in the Zhanhua Sag,Bohai Bay Basin

作　　者：张琴[1,2] 朱筱敏[1,2] 李晨溪[1] 乔李井宇 刘畅[3] 梅啸寒 杜会尧 禄佳景[4] 

机构地区：[1]中国石油大学(北京)地球科学学院,北京102249 [2]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [3]中联煤层气有限责任公司,北京100011 [4]中国石油大港油田第一采油厂,天津300280

出　　处：《石油与天然气地质》2016年第3期422-432,438,共12页Oil & Gas Geology

基　　金：国家自然科学基金项目(41302081);教育部留学回国启动基金项目(ZX20140267)

摘　　要：页岩微观孔隙特征分析和孔径定量表征是页岩油气储层评价和开发的关键。通过岩心观察、薄片鉴定、X-衍射、扫描电镜、氮气吸附等实验手段,分析了渤海湾盆地沾化凹陷富有机质页岩的矿物组成和微观孔隙类型,并对微观孔径进行了定量表征。结果表明:沙河街组页岩具有碳酸盐矿物含量高、粘土矿物含量较低的特征。根据发育位置、成因及产状,将储集空间分为孔隙与裂缝两大类,并制定了孔隙和裂缝的尺度评价标准。孔隙包括矿物基质孔隙和有机质孔隙;裂缝包括构造、层间、超压破裂、成岩和有机质收缩裂缝。氮气吸附等温曲线主要存在3种类型,分别反映了样品中微孔、中孔及宏孔的分布差异。通常氮气吸附实验能更好地表征中孔的发育特征,而扫描电镜所测孔隙更好地表征了宏孔的发育。需要进一步采用二氧化碳吸附、纳米CT及压汞实验定量表征页岩的微孔和宏孔的大小及分布。It is a key step for reservoir evaluation and development of shale gas to analyze characteristics of the micro- scopic pores in organic-rich shale and quantitatively characterize their pore size distribution. Based on core description, thin section inspection, X-diffraction, SEM and nitrogen adsorption test, this paper analyzed mineral components, classified microscopic pore types and also quantitatively characterized pore size in organic-rich shale samples of the Shahejie For- mation in the Zhanhua sag, Bohai Bay Basin. The results show that the samples are characterized by high carbonate con- tent and low clay content. According to their positions in the formation, genetic origin and occurrence, the reservoir spaces are divided into two types, namely pores and fractures, and their size classification criteria are determined. The pores con- sist of mineral matrix pores and organic pores. The fractures include structural, inter-bedded, over-pressure induced, alia- genetic and organic shrinkage fractures. Nitrogen adsorption test mainly displays three types of curves which represent the spatial distribution of mieropores, mesopores and macropores in the shale samples respectively. While nitrogen adsorption test mainly measures the mesopores and is relatively insensitive to other pore size types, SEM can reveal the characteris- tics of macropores much more clearly. It is suggested to further perform measurements of carbon dioxide adsorption, Nano- CT and mercury injection to quantitatively characterize the size and spatial distribution of the micropores and macropores in the shale.

关 键 词：氮气吸附实验 孔径定量表征 微观储集空间 矿物组成 富有机质页岩 沙河街组 沾化凹陷 渤海湾盆地 

分 类 号：TE132.2[石油与天然气工程—油气勘探]