随钻电磁波传播电阻率测量工具探测深度研究

在随钻电阻率测井中，基于相应的电阻率测量曲线和基于衰减的电阻率曲线在地层中经常出现彼此分离的现象，对电磁波电阻率测井的探测深度进行了详细的研究，研究表明这种分离与电阻率换算方法有关。同时指出基于IRPGF定义的探测深度有一定的局限性，只能用于定性分析，而且，IRPGF探测深度越大并不说明其测量结果越接近地层真电阻率，最后对导致电阻率曲线分离的因素进行了归纳，并指出利用随钻电阻率测量数据进行地层侵入评价是更为可靠的方法。

Investigation Depth of MWD Propagation Resistivity Logging

In LWD resistivity logging, the amplitude based log and the phase based log are often separated in formation. In this paper, the investigation depth of LWD propagation resistivity tool is studied in detail, the results of which show that the separation is related to the method used to convert phase and amplitude data into risistivity. The paper also indicates that the depth of investigation based on IRPGF (integrated radial pseudo geometrical factor) is at most a qualitative statement, and in such sense, that deeper IRPGF investigation depth does not mean its measurement is always closer to the uninvaded formation resistivity. At the end, the elements effecting the investigation depth are sumed up, and the more reliable method for evaluating the invaded formation with the LWD resistivity tool is put forward.