石油学报 ›› 2019, Vol. 40 ›› Issue (4): 423-433.DOI: 10.7623/syxb201904004

• 地质勘探 • 上一篇    下一篇

涪陵页岩气田平桥区块页岩气储层有机质孔发育特征

陈曼霏1, 何生1, 易积正2, 张柏桥2, 舒志国2, 何陈诚1, 杨锐1, 董田1   

  1. 1. 中国地质大学(武汉)构造与油气资源教育部重点实验室 湖北武汉 430074;
    2. 中国石油化工股份有限公司江汉油田分公司 湖北潜江 433124
  • 收稿日期:2018-07-27 修回日期:2018-12-20 出版日期:2019-04-25 发布日期:2019-05-07
  • 通讯作者: 何生,男,1956年1月生,1982年获武汉地质学院学士学位,2002年获Curtin University of Technology博士学位,现为中国地质大学(武汉)教授、博士生导师,主要从事油气地质教学和科研工作。Email:shenghe@cug.edu.cn
  • 作者简介:陈曼霏,女,1994年4月生,2016年获武汉工程科技学院学士学位,现为中国地质大学(武汉)资源学院矿产普查与勘探专业硕士研究生,主要从事页岩气地质研究。Email:chenmanfei@cug.edu.cn
  • 基金资助:

    国家自然科学基金项目(No.41690134,No.41672139)、国家科技重大专项(2016ZX05034-002-003)、中国地质调查局地质调查项目(DD20160185)、高等学校学科创新引智计划项目(B14031)和中国博士后科学基金项目(2018M640740)资助。

Development characteristics of organic pore in shale gas reservoir of Wufeng Formation-Member 1 of Longmaxi Formation in Pingqiao block, Fuling shale gas field

Chen Manfei1, He Sheng1, Yi Jizheng2, Zhang Baiqiao2, Shu Zhiguo2, He Chencheng1, Yang Rui1, Dong Tian1   

  1. 1. Key Laboratory of Tectonics and Petroleum Resources of the Ministry of Education, China University of Geosciences, Hubei Wuhan 430074, China;
    2. Sinopec Jianghan Oilfield Company, Hubei Qianjiang 433124, China
  • Received:2018-07-27 Revised:2018-12-20 Online:2019-04-25 Published:2019-05-07

摘要:

涪陵页岩气田二期产建区的平桥区块上奥陶统五峰组和下志留统龙马溪组一段(龙一段)海相富有机质页岩中纳米级有机质孔较发育,是页岩气储层的重要孔隙类型。利用氩离子抛光-场发射扫描电镜(FE-SEM)技术和Image-Pro Plus统计软件以及气体物理吸附实验,对平桥区块JY-B井五峰组和龙一段不同小层的14块页岩岩心样品进行了有机质孔形状、数量、孔径分布的观察和统计,并对有机质面孔率进行了计算。利用FE-SEM观察发现五峰组页岩样品有机质孔形状以边缘收缩的多角形为主,龙一段下部页岩样品有机质孔形状多呈不规则椭圆形和近圆形,龙一段上部页岩有机质孔多呈压扁状椭圆形、不规则近圆形和长条形;页岩样品中有机质孔的孔径主要为5~600 nm,有机质孔的主体孔径在5~30 nm,龙一段页岩样品孔径在100~600 nm的有机质孔数量相对较多;五峰组(1小层)和龙一段下部3小层页岩样品平均单颗粒有机质面孔率相对最大,其次是龙一段上部7和8小层;五峰组和龙一段下部与上部页岩样品有机质面孔率与TOC具有不同的正相关关系。采用气体吸附实验得到页岩样品中0.3~10 nm孔隙的累积孔容与TOC呈良好的线性正相关关系,表明这部分孔隙中的有机质孔占有重要地位。3套页岩层段有机质孔发育特征及差异性与页岩有机碳含量、矿物组成和构造挤压改造等因素有关。

关键词: 有机质孔, 有机质面孔率, 储层, 五峰组, 龙马溪组, 平桥区块, 页岩气田, 涪陵地区

Abstract:

As the important pore type of shale gas reservoirs, nano-organic pores are relatively developed in the marine-rich organic shale of the Upper Ordovician Wufeng Formation and Member 1 of the Lower Silurian Longmaxi Formation (Long 1 Member) in Pingqiao block of the second production phase of the Fuling shale gas field. Using the argon ion polishing-field emission scanning electron microscopy (FE-SEM), Image-Pro Plus statistical software and gas physic adsorption experiments, this study observes and statistically analyzes the shape, number and pore size distribution of organic matter pores in 14 shale core samples from different small layers of the Wufeng Formation and Long 1 Member of Well JY-B in Pingqiao block, and also calculates out the organic surface pore rate. The FE-SEM is used to observe the organic pores of shale samples in Wufeng Formation, of which the shape is mainly polygonal with edge shrinkage. The shale samples in the lower section of Long 1 Member are mostly irregularly elliptical and nearly circular, while those in the upper shale have a flattened elliptical shape, irregularly near-round and elongated. The organic pore size of shale samples is mainly between 5 and 600 nm, and the pore size of organic pores is between 5 and 30 nm. The number of organic pores with the pore size of 100-600 nm is relatively large in the shale of Long 1 Member. The average single-particle organic matter surface pore rate of Wufeng Formation (Layer 1) and the lower part of Long 1 Member (Layer 3) is relatively large, followed by Layer 7 and 8 of the upper Long 1 Member. The organic matter surface rate of Wufeng Formation, the upper Long 1 Member and the upper shale samples have different positive correlations with the total organic carbon. The gas-adsorption experiments show that the cumulative pore volume of the pores of 0.3-10 nm in shale samples has a good linear positive correlation with the total organic carbon, indicating that the organic pores in this part are dominant. The development characteristics and differences of organic pores in three sets of shale intervals are related to shale organic carbon content, mineral composition and structural extrusion.

Key words: organic pore, surface pore rate of organic matter, reservoir, Wufeng Formation, Longmaxi Formation, Pingqiao block, shale gas field, Fuling area

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