基于叠前波场模拟的合成地震记录层位标定

Well-ties with log synthetic seismogram based on prestack wavefields simulation

常规合成地震记录层位标定方法没有考虑多次波和转换波以及处理过程对层位标定的影响。为减小合成地震记录与井旁地震道在波场特征上的差异,提高合成地震记录层位标定的精度,提出基于叠前波场模拟的合成地震记录层位标定方法:首先,利用常规方法进行测井曲线编辑和地震子波提取;第二,利用反射率法模拟井旁共反射点道集;第三,对模拟的共反射点道集进行正常时差校正和叠加;最后,以叠加道作为合成地震记录对地震反射进行层位标定。试验结果表明,此方法改善了合成地震记录与井旁地震道之间在地震反射上的一致性,提高了层位标定的可靠性。

The effects of multiples, converted-waves and the processing procedure on well-ties were not taken into account in conventional well-ties method. In order to decrease the differences of wavefield characteristic between log synthetic seismogram and nearby-well seismic trace, and improve the reliability of well-ties, a new well-ties method based on prestaek wavefield simulation was proposed. Firstly, the well log was edited and the wavelet was extracted by conventional method. Secondly, the common-reflection-point gather located at the well was simulated by the reflectivity method. Thirdly, normal time difference correction and stack were applied to the simulated common-reflection-point gather. Finally, the stack trace was used as synthetic seismogram to calibrate the seismic reflections for well-ties. The results show that the consistency of synthetic seismogram and well-nearby traces was improved, and the reliability of well-ties was enhanced by using the new method.