Characters and Causes of Tight Sandstones of Yanchang Formation in Southern
详细信息
- 责任者：Zhang Shaonan (State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation ; Chengdu University of Technology ; Chengdu 610059 ; China) ; Ding Xiaoqi
- 刊名：Journal of Chengdu University of Technology
- 出版年：2010
- 卷期：37(4)
- 关键词：砂岩储集层 ; sandstone reservoirs ; 鄂尔多斯盆地 ; Ordos Basin
- 页码：p.386-394
- 图表：6 illus., 35 refs.
- 分类号：1003
- issnNo：ISSN1671-9727
- isbnNo：CN51-1634/N
摘要
The authors analyze the characters and formation mechanism of the tight sandstone reservoirs by thin section, petrophysics and SEM. The result shows that the tight sandstones have complex pore construction and high irreducible water saturation caused by many micropores. The fine reservoirs are rich in petroleum because the tight sandstones have high capillary pressures. The main causes of forming tight sandstones are the strong compaction and cementation. Solution of organic acid is late because of the low temperature. So, the solution is weak. Chlorite rims can retard the compaction. Similarly, little plastic particles can also decrease their shape change caused by compaction. The later solution is determined by the former petrophysics and cementation. If pores are well-developed, the solution will develop as well. Similarly, if the laumonite cementation is strong, the later solution will more strong. The weak compaction, strong solution and fractures are the keys for the developing of high quality reservoirs.