摘要
为了系统描述渝东北地区下志留统龙马溪组海相页岩的微观孔隙结构,应用氩离子抛光聚焦离子束扫描电镜（FIB-SEM）、低温N2吸附及高压压汞实验定性和定量测试WX-1井岩心样品的孔喉形态、连通性、比表面积及孔径分布。通过对比分析不同实验测试的孔径分布,实现对页岩样品从微孔到宏孔的精细描述,并探讨了影响孔隙发育的控制因素。研究结果表明,龙马溪组页岩储层主要发育有机质孔、黏土矿物层间孔、黄铁矿晶间孔、颗粒边缘溶蚀孔及微裂缝等5种孔隙类型。受到后期压实作用的影响,有机质孔隙发育具有微观非均质性。纳米孔隙类型复杂、形态多样,主要为开放透气性孔,但存在细颈状墨水瓶孔及少量一端封闭的不透气性孔等影响页岩气的渗流;孔径分布具有“双峰”特点,纳米孔主要孔径为2~10nm、30~90nm,即直径〈100nm的孔隙提供了大部分总孔体积,为页岩储层主要发育的孔隙类型。孔隙发育受多种因素的控制,直径≤50nm微孔、中孔的发育与有机质有关,有机碳含量与微孔、中孔的孔体积呈正相关性;直径〉50nm宏孔的发育与黏土矿物含量有关,随着黏土矿物含量的增加,宏孔的体积、比表面积也随之增大。
Abstract： Field-emission environmental scanning electron nitrogen adsorption and high-pressure mercury injection are characterize the micropore structures and their morphology, pore-size distribution from drilling Well WX-1 core samples microscope （FE-SEM）, low-pressure used to qualitatively and quantitatively connectivity, specific surface area and of Lower Silurian Longmaxi Formation shale in Northeast Chongqing. The pore-size distributions of different experiments are comprehensively analyzed to gain a fine characterization from microscopic scale to macroscopic scale. It shows that there are five kinds of pores types of the shale, including organic micropores,interparticle pores between clay minerals, intracrystalline pores between {ramboid pyrite, particle edge dissolved pores and micro-cracks. Distribution of the organic nanopores exhibits non-uniformity duo to the burial compaction. It also reveals that the pore structures of the shale gas reservoir of Longmaxi Formation are relatively complex and mostly in open shapes and there are some ink-bottle- like pores and blind pores which influence the flow of gas. The pore size distribution of Longmaxi shale is bimodal, with the dominant pore diameter in the range of 2~10 nm and 30~90 nm, and the nanopores with a diameter less than 100 nm make up most of the pore volume of shale pores. Many factors affect the development of the shale. Organic matter is an important factor controlling the formation of micro- and meso-pores, evidenced by positive correlations between the total organic carbon （TOC） content and the pore volume of micro- and meso-pores. Macropores are associated with clay minerals, the more the content of clay minerals, the greater the specific area and pore volume of macropores.
出处
《成都理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2016年第3期308-319,共12页
Journal of Chengdu University of Technology: Science & Technology Edition
基金
国家科技重大专项(2011ZX05018-002)
关键词
页岩储层
孔隙结构
低温氮气吸附
高压压汞
早志留世
龙马溪组
渝东北地区
shale gas reservoirs
pore structure
low pressure nitrogen adsorption
high pressure mercury injection
early Silurian
Longmaxi Formation
Northeast Chongqing
作者简介
[第一作者]武瑾（1988一），女，工程师，主要从事页岩气储层评价工作，E-mail：w@nouc@petrochina．com．cn。
