视电阻率法测井在划分多年冻土层的应用效果

Effect of Identifying Permafrost by Apparent Resistivity Logging

论述了在相同岩性的地层中,冻结层视电阻率高于非冻结层视电阻率,在冻结层上、下界面位置视电阻率产生跃变。利用电极距为0.5m的电位电极系的视电阻率测井曲线的高阻异常拐变特征点,可划分出冻结层的上、下界面及厚度。初步探讨了利用视电阻率电位测井曲线,划分多年冻结层的效果及精度与冻结层岩性、含冰量和井径等因素的关系。

The principle of apparent resistivity logging is introduced in this paper. If the soil type is the same the apparent resistivity of frozen stratum is much higher than that of unfrozen stratum. Therefore, there exist jump points of the apparent resistivity both at the top and the bottom interfaces of frozen stratum. By using the turning point on jthe curve of the apparent resistivity logging obtained from the system of potential and electrode with the distance between electrodes of 0.5 m, we can identify the locations of both the top and bottom interfaces and thickness of permafrost. The effect and accuracy of using the apparent resistivity logging curve to identify permafrost and its influencing factors, such as soil properties, ice content and drilling diameter are discussed.