基于测井约束反演的基岩风化带含水层富水性分析

Water-rich analysis of aquifer in the weathering zone of bedrock based on logging constraint inversion

反演是瞬变电磁资料解释的重要手段,而由于缺乏足够的高低频信息,常用的反演方法存在横向连续性差、纵向分辨率低、对数据的控制力差等缺陷,对地层的空间刻画能力较低。为了提高反演精度,基于Occam算法和测井曲线建立了约束地质模型,充分利用测井信息细化反演细节,以陕北某煤矿为研究对象,将传统光滑模型与测井约束模型进行对比。研究结果表明,2种模型与实测数据均有较高的拟合度,但光滑模型易受曲线尾支跳变点影响从而失去真实的地质信息;测井约束模型能充分利用区内各地层电性特征从而减少突变,使得横向连续性增强,同时对于纵向分辨率也有一定提高,反演结果与实际情况吻合,可作为反演常用手段以提高资料解释精度。

Inversion is an important means for the interpretation of transient electromagnetic information.Due to the inadequate high-low frequency information,there exists the shortages of poor lateral continuity,low longitudinal resolution and poor control capability for data,thus having a poor scaling capability for the space of strata.In order to improve the inversion accuracy,a constrained geologic model is built based on the Occam algorithm and logging curve.With the detailed inversion of logging information and taking a certain coal mine in northern Shaanxi as the research object,the traditional smooth model is compared with the constrained geological model.The research results show that the two models have a high degree of fitting with the measured data,but the smooth model is easily affected by the transition point of the curve tail,thus loss of true geological information.The logging constraint model can make full use of the electrical characteristics of each stratum in the area to reduce sudden changes and strengthen horizontal continuity,the longitudinal resolution is also improved to a certain extent,and the inversion results are consistent with the actual conditions,which can be adopted as a commonly used inversion means for boosting the information interpreting accuracy.