基于MATLAB的小波变换在沉积旋回研究中的应用

以黑龙江双鸭山盆地828井为例,选择基于MATLAB的wavelet 1-D和continueswavelet 1-D对GR曲线进行变换分析。结果表明,在Daubechies二进制小波系的db5wavelet1-D分析下,828井60m～570m区间共识别出二个二级旋回、四个三级旋回、八个四级旋回,分别对应于第11、第10、第8尺度的小波变换系数。在continues wavelet 1-D分析下,在10层分解后10个尺度下小波变换高频成份小波系数识别出四个三级层序,与wavelet 1-D变换d10所代表的三级沉积旋回一致。该方法将测井信号与深度的关系转换为深度与尺度域的变化关系,建立与之有对应关系的各级层序界面,使地层内部的隐蔽旋回结构得以清晰展示,这对提高旋回层序的划分精度具有重要的意义。

APPLICATION OF WAVELET TRANSFORM IN SEDIMENTARY CYCLE RESEARCH BASED ON MATLAB

Taking the well 828 of shuangyashan basin in Heilongjiang province for example,the GR log was transformed and analyzed based on wavelet 1-D and continues wavelet 1-D of MATLAB.The result showed that 60m-570m section of well 828 can be divided into two second order cycles,four third order cycles and eight order cycles,which corresponded to wavelet transform coefficients of eleventh,tenth,eighth scale respectively by analyzed wavelet db5 of daubechies binary wavelet;Under the analyze of continues wavelet 1-D,four third order cycles were identified depended on ten level decomposition and ten scale high frequency components wavelet coefficient,which consistent well with the third cycles represented by d10 transformed by wavelet 1-D.This method converts the relationship of log signal and depth into depth and scale domain,builds certain corresponding relations of each sequence boundary and makes the hidden stratum cycling structure much clearer.This method has great significance on the improvement of the precision of cyclic sequence division.