Genesis and Hydrocarbon Significance of Vesicular Ignimbrite: A Case Study from Fengcheng Formation, Wu-Xia Area, Junggar Basin , NW China
详细信息
- 责任者：Zhu Shifa (State Key Laboratory of Petroleum Resource and Prospecting ; China University of Petroleum ; Beijing 102249 ; China) ; Zhu Xiaomin
- 刊名：Petroleum Exploration and Development
- 出版年：2012
- 卷期：39(2)
- 关键词：火山碎屑流 ; pyroclastic flows ; 熔结凝灰岩 ; ignimbrite ; 准噶尔盆地 ; Junggar Basin
- 页码：p.162-171
- 图表：8 illus., 1 table, 18 refs.
- 分类号：1003
- issnNo：ISSN1000-0747
- isbnNo：CN11-2360/TE
摘要
On the basis of a large number of cores and thin-sections observations, the petrologic and pore evolution characteristics of ignimbrite in the Fengcheng Formation in the Wu-Xia area, Junggar Basin, are studied, and the genesis of vesicular ignimbrite and formation mechanism of vesicles are analyzed. Volcanic action in the Fengcheng Formation is characterized by welded pyroclastic rocks. There are predominant plastic shards with rounded edges and obvious devitrification in the rocks. Plastic debris is deformed and wrinkled, and crystal fragments are usually corroded. A lot of lithophysae occur in the ignimbrite, and welded texture is obscured. Vesicles are the cavities of lithophysae, which are formed by solidification contraction. They have little or no late filling cement because the volatile constituent and water vapour in the bubbles have escaped with the help of devitrification. Lithophysae distribution within a cooling unit obviously has the characteristic of zonation in vertical: increasing upwards and then decreasing gradually. The cavities of lithophysae greatly improve the reservoir capability of ignimbrite. Influenced by intensive welded process, lithophysae are not subject to collapse or damage. In the study area, deeply buried vesicular ignimbrite is an important hydrocarbon reservoir rock, and the vesicular ignimbrite has good petroliferous property.
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |