Reservoir Conditions of Shale Gas in the Lower Cambrian Niutitang Formation, Northwestern Hunan Province
详细信息
- 责任者：Xiao Zhenghui (Hunan Provincial Key Laboratory of Shale Gas Resource Utilization ; Hunan University of Science and Technology ; Xiangtan 411201 ; China) ; Wang Zhaohui
- 刊名：Acta Geologica Sinica
- 出版年：2013
- 卷期：87(10)
- 关键词：页岩气 ; shale gas ; 湖南 ; Hunan Province
- 页码：p.1612-1623
- 图表：8 illus., 3 tables, 30 refs.
- 分类号：1003
- issnNo：ISSN0001-5717
- isbnNo：CN11-1951/P
摘要
To objectively evaluate shale gas exploration potential in the Lower Cambrian Niutitang Formation,northwestern Hunan,reservoir conditions of shale gas were investigated by means of X-ray diffraction(XRD),scanning electron microscopy(SEM)and scanning probe microscopy(SPM)and so on.XRD analysis results suggest that brittle mineral contents range from 53.8percent to 98.1percent,with an average content of 77.9percent.High value zones of brittleness mineral contents are mainly distributed in the Zhangjiajie Ganziping,Sancha and the surrounding areas.High magnification SEM analysis results indicate that there exist five kinds of pores and fractures,including residual primary pores,organic micropores,dissolution pores in unstable minerals,interlayer microfracture in minerals,as well as tectonic fractures.Of which structural fractures,organic micropores,dissolution pores in unstable minerals are the main constituents.SPM analysis results suggest that honeycomb organic matters distributed mostly in strip-shaped and disperse states are rich in the mud-shale of Lower Cambrian Niutitang Formation,northwestern Hunan,with nanoscopic porosities well developed in organic matters.Test results of Ultrapore-200helium porosimeter show that porosity of mud-shale is low,with a range from 0.6percent to 11.7percent(an average content of 4.6percent)and the dominant factor of porosity is structural fractures,followed by TOC contents and feldspar contents.Test results of ULTRA-PERMTM200permeameter show that permeability of mud-shale is relatively low,ranging from 0.002mD to 0.06mD(an average content of 0.014mD)and the dominant factor of permeability is structural fractures,followed by interlayer microfracture in minerals.Isothermal adsorption experimental results show that mud-shale of Lower Cambrian Niutitang Formation had good adsorbability and TOC content may be the dominant factor to affect the mud-shale.