Characteristics of NMR Water Displacing Oil and Influencing Factors in Extra-Low Permeable Sandstones: Taking the Yanchang Group in Ordos Basin as an Example
详细信息
- 责任者：Gao Hui (College of Petroleum Engineering ; Xi’an Petroleum University ; Xi’an 710065 ; China) ; Wang Xiaopeng
- 刊名：Geological Journal of China Universities
- 出版年：2013
- 卷期：19(2)
- 关键词：低渗透储集层 ; low permeability reservoirs ; 鄂尔多斯盆地 ; Ordos Basin
- 页码：p.364-372
- 图表：illus., 1 table, 29 refs.
- 分类号：1003
- issnNo：ISSN1006-7493
- isbnNo：CN32-1440/P
摘要
Samples of Yanchang group in Ordos Basin were tested using the NMR technique before and after the water-looding experiments in order to analyze the characteristics of water displacing oil and to reveal the dominant factors for extra-low permeable sandstones.The results show that oil phase T 2 patterns present double peaks in an irreducible water condition with crossing points at about 16.68 ms and movable oil parameters are sensitive to permeability.The right peak decreases to different extents after water-flooding;while the drop of left peak is related to the imbibition of capillary.If the imbibition of capillary can be utilized effectively,recovery can be enhanced.Average value of movable oil percentage is 57.62 and displacement efficiency is 37.33.There is about 20.29% movable oil that has not been flooded out and the development potential is still great after water displacing oil for extra-low permeable sandstones.Physical property,matching relationship of pore throat,degrees of microcrack development,occurrence forms of clay mineral are the main factors affecting displacement efficiency.Correlation between displacement efficiency and movable oil percentage confirms that movable oil percentage of NMR is the upper limit of displacement efficiency.