规格化总梯度法模型试验与分析

MODEL EXPERIMENT AND ITS ANALYSIS FOR THE NORMALIZED TOTAL GRADIENT METHOD

近年来,通过对规格化总梯度方法的研究和大量的模型试验以及部分实际资料试算,进一步肯定了方法的找矿效果。 规格化总梯度法是一种既经济又简便的解释手段,它适用于剖面测量。该方法的实质就是将重力剖面数据向下半空间延拓若干高度,求出各高度水平上的垂向与水平一次导数,在合成总梯度后再进行规格化运算,可以得到剖面上的断面等值图。它展示了下半空间的总梯度场分布,直观地反映出地质体特征,从而避免了人为因素的干扰。同时还可根据不同频段的异常特征来区分不同层次的地质体。有关这方面的文章已有论述。 本文仅就所做的模型试验结果进行对比分析,使我们对各种较常见的地质体所产生的规格化总梯度异常特征有所了解。这些规律将有助于对实际资料的推断解释。

In recent years, through the research for the normalized total gradient method, a large number of model experiments and the test for some real data have been made, the validity of the method in oil/gas exploration is confirmed and approved once again. The normalized total gradient method is a method for interpretation. It is both economic and easygoing and is suitable for the profiling. The essence of it is to make a downward continuation for the data of gravity profiling downwards to different levels in the lower half-space and to extract the corresponding vertical and horizontal derivatives of the first order. The normalization operation is conducted after the total gradient is composed. Through such a procedure, the isoplethic map of the section, which reveals the distribution of the total gradient field in the lower half-space and shows the features of the geological body intuitively, could be plotted and the artifitial influency could thus be avoided. Additionally, different geological bodies could be distinguished from each other according to the characteristics of the anomaly with different frequencies. The related problems have already been discussed in many of the published articles. In this paper, we only make a comparison and analysis for model experiments of ourselves. The purpose of doing so is to have an understanding about the characteristics of the normalized total gradient anomalies resulted from some common geological bodies. Hopefully, this might be serviceable for real, data interpretation.