SP Log Response Mechanism in Undercompaction and Overpressure Formation

详细信息   

• 责任者：Zhang Chong (Key Laboratory of Exploration Technologies for Oil and Gas Resources of Ministry of Education at Yangtze University Hubei Jingzhou 434023 ; China) ; Mao Zhiqiang
• 刊名：Chinese Journal of Geophysics
• 出版年：2011
• 卷期：54(8)
• 关键词：超压 ; overpressure ; 自然电位测井 ; self-potential logging
• 页码：p.2177-2183
• 图表：4 illus., 1 table, 20 refs.
• 分类号：1600
• issnNo：ISSN0001-5733
• isbnNo：CN11-2074/P

摘要

This study is focused on undercompaction and overpressure formation, the equations of the membrane potential for overpressure shale and shaly sandstone are developed by dual water model and thermodynamics theory. The effect of compaction to membrane potential and the response characteristic of SP log are analyzed. It is showed that the compaction has significant effect on membrane potential of shale. Under invasion of filtrate with high salinity, the membrane potential of shale increases as compaction coefficient increases. In drilling condition of fresh water mud filtrate, the membrane potential of shale decreases when compaction coefficient increases. The effect of compaction on the membrane potential of shaly sandstone with low Q, is not significant. The membrane potential of shaly sandstone is affected more by Qv than by compaction. The base-line of SP in shale interval is shifted by undercompaction and the SP anomaly magnitude in shaly sandstone with undercompaction and overpressure is lower than that of the normal compacted formation. The research has very important reference value understanding SP log response mechanism and identifying oil lay in undercompaction overpressure formation. on andoverpressure formation.