摘要
为实现自然电位测井的高效正演计算,以定量研究各种因素影响,针对自然电位的激励源——偶电层的分布进行了研究。通过对自然电位产生原因及偶电层对自然电位贡献的分析,认为只有泥岩井壁、侵入带中砂泥岩界面和侵入带与原状地层分界面处的偶电层对自然电位测井值有贡献,而研究砂岩层处的自然电位异常,则仅考虑由侵入带与原状地层界面处的偶电层即可。通过直流电场与静电场的类比,推出了偶极源的面电流密度表达式,并通过计算研究了均匀介质中侵入深度的影响。结果显示,自然电位曲线形状随侵入深度增加而变得平缓,异常幅度减小。
In order to facilitate efficient modeling of SP-log, and investigate the influences factors quantitatively, investigation on the stimulating source for SP, the electrical double layer （EDL） was performed. Through analyzing of the physical origin of spontaneous potential and the contribution of EDL to SP, it is clear that only the EDL at the borehole wall of shale layer, sand-shale boundary with invaded zone and that between invaded zone and virgin formation would contribute to the value of SP- log. In case only the anomalies of sand layer are concerned, to calculate the contribution of the EDL between invaded zone and virgin formation is sufficient. By analog of direct current electric field and static electric field, expression for the surface current density of EDL is deduced. SP logs for different depth of invasion were calculated for media with uniform resistivity. The results show that the form of SP-log becomes flatter with the increasing depth of invasion, the amplitude of anomaly become smaller at the same time.
出处
《吉林大学学报（地球科学版）》
EI
CAS
CSCD
北大核心
2012年第4期895-899,共5页
Journal of Jilin University：Earth Science Edition
基金
国家自然科学基金项目(40874057)
国家'863'计划项目(2009AA09A202-01-01)
关键词
自然电位测井
偶电层
电化学电动势
侵入深度影响
spontaneous potential logging
electric double layer
electrochemical EMF
influence ofinvasion depth
