初至波层析反演静校正方法研究

Study of first break Tomographic inversion method for static corrections.

作者在地表一致性模型的基础上研制出一种基于三维层析成像反演的三维层析静校正方法。适用于宽线、弯线、传统的二维和目前广泛使用的三维勘探。在地形及低降速带地质结构复杂的探区 ,低降速带厚度及速度估算的精度是静校正处理的关键。本文根据三维地震观测的初至走时数据 ,利用最小平方与 QR分解相结合的算法在三维空间重建低降速带速度模型 ,根据重建速度模型实现了静校正长波长分量与短波长分量的同步计算。在初至走时观测数据的拾取方面 ,采用分形算法克服了初至波波形差异以及折射波相位反转等问题导致的拾取误差 ,实现了三维初至拾取的大规模全自动化运算。野外实际资料的处理结果表明 。

The authors developed a software of 3 D tomographic statics based on 3 D tomographic inversion on the basis of surface consistent model. The software is suitable for wide line,crooked line,2 D conventional survey and currently widely used 3 D survey. In topographic and complex area,the resolution of evaluation of weathering depth and velocity is the key of static processing. The paper reconstructed weathering velocity model in 3 D space using the algorithm combining least square with QR decomposition based on first break travel times data observed in 3 D seismic survey and gained the synchronous calculation on long wavelength and short wavelength of statics. Adoption of fractal based algorithm overcame the detecting errors caused by waveform difference of first break and phase turnover of refraction,obtained large scaled,fully automatic operations of 3 D first break detection in detection of observed first break travel time data. The processing results of field data show that the 3 D tomographic method for static corrections presented in the article is very effective.