Tufa Character and Its Oil-Gas Significance of Ordovician Outcrops in the Northwest Margin of
详细信息
- 责任者：Niu Yongbin (College of Geo-Resources and Information ; China University of Petroleum ; Qingdao 266555 ; China) ; Zhong Jianhua
- 刊名：Journal of China University of Petroleum
- 出版年：2010
- 卷期：34(4)
- 关键词：碳酸盐岩储集层 ; carbonate reservoirs ; 石灰华 ; tufa ; 塔里木盆地 ; Tarim Basin
- 页码：p.25-32
- 图表：7 illus., 3 tables, 18 refs.
- 分类号：1003
- issnNo：ISSN1673-5005
- isbnNo：CN37-1441/TE
摘要
By using methods of rock slice, thin-section analysis and porosity and permeability testing, the tufa sedimentary characteristics were studied, and the origin of tufa was analyzed through the analysis of geomorphology and karst dynamics. The samples were collected from Ordovician outcrops in the fifth track of Bachu County and Keping sulfur gulch based on field observation. The results show that the tufa deposition is a good kind of reservoir with high porosity and permeability. The origin of tufa of Ordovician in the fifth track of Bachu County is that the fresh water which was rich in CO2 corroded limestone, then the underground river produced. When the karst water flowed out of the underground river, CO2 escaped and CaCO3 deposited largely in the marsh of epicontinental margin with the pressure declining and the temperature rising. The origin of tufa sedimentation of Ordovician in Keping sulfur gulch is that fracture corroded to enlarge into karat cave, then tufa formed as CaCO3 deposited by stage.