渝东南彭水地区龙马溪组页岩孔隙结构特征及吸附性能控制因素

作    者:孙寅森1,2,3,郭少斌1,2
单    位:(1 中国地质大学(北京)能源学院; 2 国土资源部页岩气资源战略评价重点实验室) ;3 中国石油长城钻探工程有限公司解释研究中心)
基金项目:受国家科技重大专项“不同类型页岩气生成机理与富集规律研究”资助
摘    要:
以渝东南彭水地区志留系龙马溪组富有机质泥页岩为研究对象,通过扫描电镜以及场发射扫描电镜,同时对页岩微观孔隙结构进行定性观察;借助核磁共振与氮气吸附实验,联合定量表征页岩的孔隙结构特征;并通过甲烷等温吸附实验,探讨了页岩孔隙吸附性能的控制因素。研究表明:彭水地区龙马溪组页岩有机质孔和黏土矿物层间孔最为发育;氮气吸附实验和核磁共振共同表征页岩孔径分布曲线特征呈双峰或三峰形态,且左峰明显大于右峰,表明页岩介孔最为发育,约占孔隙的73.5%,同时还发育部分微孔和宏孔,分别占13.4%和13.1%,其中2~5 nm的介孔是页岩孔体积的主要贡献者;页岩孔隙结构不规整,多为平行壁的狭缝型孔;孔隙发育主要受有机质含量控制,其次,岩石矿物成分也对页岩孔隙发育有一定影响,其中脆性矿物更有利于微裂缝和宏孔的发育,黏土矿物含量与页岩比表面积和孔体积呈较弱的正相关性;页岩吸附性能受页岩比表面积和孔体积控制,有机质含量是页岩吸附性能的主要控制因素,随着有机质含量增加,页岩的吸附性能提高,其次,页岩吸附性能与黏土矿物含量呈弱正相关性,而与脆性矿物含量呈弱负相关性。
关键词:渝东南; 彭水地区;龙马溪组;页岩;孔隙结构;吸附性能

Pore Structure of Shale and Controlling Factors of Adsorption Performance of Longmaxi Formation in Pengshui Area, Southeast Chongqing

Author's Name: Sun Yinsen, Guo Shaobin
Institution: Institute of Energy Resources, China University of Geosciences
Abstract:
Based on the experiment of SEM, FESEM and NMR, and combined with the experiment of N2 gas adsorption and isothermal adsorption of methane, the control factors of adsorption capacity of Silurian Longmaxi Shale in Pengshui area, Southeast Chongqing, were discussed. It is shown that organic matter pores and clay mineral pores are mainly developed in shale. The meso-pores account for about 73.5% of shale pore, and the micro-pores and macro-pores account for 13.4% and 13.1% respectively. The meso-pores(2~5nm) make major contribution to the pore volume. The pore structure of shale is irregular, mostly made up of slit pores parallelling the palte of structure. It is concluded that organic matter content is a key factor to control the development of shale pore and the adsorption capacity. There is a weak correlation between shale pore and mineral composition. The adsorption capacity of shale has a positive correlation with specific surface area, pore volume and organic matter content. And it also has a weak positive correlation with clay mineral content and has a weak negative correlation with brittle mineral content.
Keywords: Shale; Pore structure; Adsorption capacity; Longmaxi Formation; Pengshui area; Southeast Chongqing
投稿时间: 2017-05-13  
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