侵入带对视电阻率的影响

EFFECT OF THE INVADED ZONE ON APPARENT RESISTIVITY

利用混合法研究了侵入带的三种模式——台阶型、斜坡型、具有低阻环带的侵入带对电位电极系视电阻率的影响。其目的， 一是确定常用的台阶型侵入带引入的误差， 二是研究细致地探测侵入带的方法。研究结果一方面表明了考虑过渡带和低阻环带可以提高测井解释的准确度，另一方面也为用多电极系电阻率测井探测侵入带提供了理论依据。

The three invasion types——the step, the slop, the invaded zone with an annulus, have been presented in order to define under what conditions a significant error is introduced by the step profile assumption and to examine how the invasion types may be detected. The effects of the three invasion types on the normal apparent resistivity were studied. The results indicate the effect of the transition zone and the annulus on the resistivity log interpretation is significant. This study provides a theoretical basis for detecting the invasion types with the multipleelectrode logging tool.