深度域合成地震记录的制作方法研究

A method for synthesizing seismogram in depth domain.

在时间域 ,合成地震记录是地震子波与反射系数的褶积。深度域的合成地震记录也与时间域类似。只不过先要将时间域的子波转换成深度域的子波 ;然后利用声波时差曲线和密度曲线计算出深度域的反射系数 ,再二者褶积便可得到深度域的合成地震记录。本方法的关键在于提取子波和计算反射系数。要在深度偏移剖面上选取品质较好的井旁地震道计算子波的主频 ,要选用零相位子波。在计算反射系数之前 ,要对声波时差曲线和密度曲线进行校正。

In time domain, synthetic seismogram results from the convolution of seismic wavelet with reflection coefficients. Seismogram synthesizing in depth domain is similar to that in time domain. synthetic seismogram in depth domain is produced in three major steps: 1) transforming time-domain seismic wavelet into depth domain wavelet, 2) deriving depth-domain reflection coefficients from both acoustic and density logging curves, and 3) convolving seismic wavelet with the reflection coefficients. The key of this method lies in wavelet obtainment and reflection coefficient estimation. The dominant frequency of wavelet is estimated by using quality borehole-side seismic trace of migrated depth section, and zero phase wavelet is used here. Acoustic and density logging curves must be revised reasonably beforehand to produce reliable reflection coefficients.