地球物理测井高分辨率处理技术

High-resolution processing technique for geophysical logging data

鉴于目前的高分辨率地球物理测井技术存在较严重的局限性，本文提出了一种基于分辨率信息熵的地球物理测井高分辨率处理技术。分辨率信息熵定义为测井曲线去均值后的过零数，它表示测井曲线分辨能力的大小，是测井曲线分辨率信息的量度。它具有确定性、非负性、可加性和相对性等性质。由于测并分辨率信息曲线的频率域结构特征是：随频率的增加，幅度呈下降趋势，在某一频率以后，幅度不再下降；低频端有效频带的宽度、低频端幅度下降的趋势随分辨率信息曲线的变化而异。因此可通过改变频率结构来改变测井曲线的分辨率信息熵，从而改变测井曲线的分辨率。具体作法是：首先选择一条高分辨率的测井曲线作为基本曲线，以该曲线为标准调整匹配曲线的频率结构或将该曲线上含有的高分辨率信息的颇丰补偿到匹配曲线上，从而提高匹配曲线的分辨率。它们都以基本曲线为依据，处理的又是分辨率信息，这就保证了处理后的测井曲线有可靠的分辨率和正确的测井值。

In view of the fact that existing high-resolution geophysical logging techniques have severe limitation, a new high-resolution processing technique for geophysical logging data has been developed which is based on resolution in formation entropyResolution in formation entropy is defined as the times for which a logging curve goes across zero line after average value is subtracted from the curveland it means resolution level of logging curve and is a measure of resolution information.Resolution information entropy is characterized as definiteness, nonnegativeity, additivity, relativity and so on. Characteristics of resolution information curve in frequency domain are as follows:amplitude decreases with the increase of frequency till a frequency value 3both effective frequency band width and amplitude of the low frequency part decrease with the variation of resloution in formation curve. Thus, the resolution in formation entropy of logging curve may be improved by changing frequency structure, so that the resolution of logging curve will be ameliorated desirably.In this technique, a high-resolution logging curve is taken as standard curve to adjust frequency structure of a matched logging curve, or to add the frequency involving high-resolution informations to the matched curve to thus improve resolution of the matched curve. All matched curves refer to standard logging curve and only resolution informations are processed, so that processed logging curves have reliable resolution and correct values.