地学前缘 ›› 2016, Vol. 23 ›› Issue (2): 167-175.DOI: 10.13745/j.esf.2016.02.017

• 页岩储层特征与评价 • 上一篇    下一篇

沁水盆地煤系地层页岩气储层特征及评价

付娟娟,郭少斌,高全芳   

  1. 中国地质大学(北京) 能源学院, 北京 100083
  • 收稿日期:2015-09-12 修回日期:2015-11-01 出版日期:2016-03-15 发布日期:2016-03-15
  • 通讯作者: 郭少斌(1962—)，男，教授，博士生导师，从事层序地层学、储层评价和油气资源评价方面的教学和科研工作。E-mail:guosb58@126.com
  • 作者简介:付娟娟(1981—)，女，博士研究生，工程师，矿产普查与勘探专业。E-mail:juanjuanfu_2012@hotmail.com
  • 基金资助:

    中国地质调查局项目“沁水盆地及周缘页岩气资源调查评价”(2014 - 258)

Reservoir characteristics and enrichment conditions of shale gas in the CarboniferousPermian coalbearing formations of Qinshui Basin.

  • Received:2015-09-12 Revised:2015-11-01 Online:2016-03-15 Published:2016-03-15

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摘要：

沁水盆地是我国重要的含煤盆地，不仅其煤炭及煤层气资源丰富，在上古生界石炭纪—二叠纪地层中还有大量页岩发育。而目前，针对该地区页岩地层的相关研究极少，该地区页岩气资源是否具有勘探开发潜力有待深入而细致的研究。本文以沁水盆地上古生界石炭系—二叠系海陆交互相页岩储层为研究对象，通过薄片鉴定、X线衍射分析、氩离子抛光扫描电镜分析、核磁共振、氦气吸附等实验方法，研究了富有机质页岩储层有机质含量、类型、成熟度等有机地化特征以及储集空间类型、物性、矿物组成、孔隙结构等储层特征。在此基础上，对研究区页岩储层的勘探开发潜力进行了评价。结果表明：沁水盆地石炭纪—二叠纪富有机质页岩储层中发育形态各异的不同类型孔隙及微裂缝。其中，矿物基质孔十分发育，主要包括有呈片状、三角形及不规则形态的粒间孔和晶间孔等；而有机质孔不发育，呈点状，偶见椭圆型。从孔隙结构上看，孔隙具有较大的比表面积，主要分布在2.84~6.44 m2/g，平均值为4.26 m2/g。平均孔径分布在3.64~10.34 nm，以中孔隙发育为主。从矿物组成来看，各矿物含量比例适中，黏土矿物含量较高，达到57.5%，有利于微孔隙发育和页岩气的吸附；以石英及长石为代表的脆性矿物含量较高，达到41.3%，易于后期压裂造缝。从有机地化特征来看，有机碳含量高，有机质类型以腐泥腐殖型为主，且受中生代异常地温场控制，有机质热成熟度高，有利于页岩气的生成和吸附存储。总体来说，虽然研究区石炭纪—二叠纪页岩储层埋深浅，但有机地化参数、矿物组成、孔隙发育及结构特征都有利于页岩生烃和页岩气储存，具有较大的勘探与开发潜力。

关键词: 沁水盆地, 石炭纪—二叠纪, 页岩, 储层特征

Abstract:

Qinshui Basin, as one of the most important coalbearing basins in China, not only has plenty of coal and coalbed methane resources, but also has a lot of shale reservoirs. However, there is little research on the characteristics and potential evaluation of shale gas reservoirs in this basin. In this paper, we studied the characteristics of shale gas reservoirs in the Upper Paleozoic of Qinshui Basin, China. Comprehensive experimental methods, including Xray diffraction, NMR, FIBSEM, microscopic identification of thin sections and nitrogen adsorption etc. were applied to analyze the characteristics of organic geochemistry, rock and mineral composition and pores evolution of organicrich shale gas reservoirs. On this basis, the exploration and development potential of shale reservoirs in the study area is evaluated. The results show that different types of pores and micro fractures developed here, which provide enough spaces for the storage of shale gas. Mineral pores, mainly including intergranular pores and intercrystalline pores in shapes of plate, triangle or irregular are well developed, whereas only a small amount of organic pores in shapes of dot or occasional ellipse developed. Porosity has a large specific surface area, which has a range from 2.84 m2/g to 6.44 m2/g with an average of 4.26 m2/g. The average value of pore size distribution is between 3.64 nm and 10.34 nm, which means mainly mesopores developed. The appropriate ratio of mineral composition, which is composed of 57.5% of clay minerals and 41.3% of brittle minerals, is pretty good for the development of mircopores, gas absorption and fracturing. High value of TOC and Ro, caused by abnormal thermal gradient in Mesozoic, provided favorable conditions for shale gas formation and storage. On the whole, though the burial depth is shallow, there is great exploration and development potential for shale gas in the CP period in the Qinshui Basin because the organic chemical conditions, mineral composition and reservoir characteristics are quite suitable for the formation and storage of shale gas.

Key words: Qinshui Basin, CP period, shale gas, reservoir characteristics

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