Elements and gas enrichment laws of sweet spots in shale gas reservoir: A case study of the Longmaxi Fm in Changning Block, Sichuan Basin

被引：1
|
作者：
Pan R. [1 ]
Gong Q. [1 ]
Yan J. [1 ]
Jin J. [1 ]
机构：
[1] Hubei Cooperative Innovation Center of Unconventional Oil and Gas, Yangtze University, Wuhan, 430100, Hubei
来源：
Natural Gas Industry | 2016年 / 36卷 / 03期
基金：
中国国家自然科学基金;
关键词：
Changning Block; Early Silurian; Elements; Gas enrichment laws; Shale gas; Sichuan Basin; Sweet spot; Weiyuan Block;
D O I：
10.3787/j.issn.1000-0976.2016.03.002
中图分类号：
学科分类号：
摘要：
Identification of sweet spot is of great significance in confirming shale gas prospects to realize large-scale economic shale gas development. In this paper, geological characteristics of shale gas reservoirs were compared and analyzed on the basis of abundant data of domestic and foreign shale gas reservoirs. Key elements of sweet spots were illustrated, including net thickness of gas shale, total organic carbon (TOC) content, types and maturity (Ro) of organic matters, rock matrix and its physical properties (porosity and permeability), and development characteristics of natural fractures. After the data in Changning and Weiyuan blocks, Sichuan Basin, were analyzed, the geologic laws of shale gas enrichment were summarized on the basis of the economic exploitation characteristics of shale gas and the correlation between the elements. The elements of favorable "sweet spots" of marine shale gas reservoirs in Changning block and their distribution characteristics were confirmed. Firstly, the quality of gas source rocks is ensured with the continuous thickness of effective gas shale larger than 30 m, TOC>2.0% and Ro=2.4-3.5%. Secondly, the quality of reservoir is ensured with the brittle minerals content being 3069%, the clay mineral content lower than 30% and a single lamination thickness being 0.1-1.0 m. And thirdly, the porosity is higher than 2.0%, the permeability is larger than 50 nD, gas content is higher than 1.45 m3/t, and formation is under normal pressure-overpressure system, which ensures the production modes and capacities. Finally, the primary and secondary elements that control the "sweet spots" of shale gas reservoirs were further analyzed and their restrictive relationships with each other were also discussed. © 2016, Natural Gas Industry Journal Agency. All right reserved.
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页码：7 / 13
页数：6
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