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在地表一致性模型的基础上提出一种可适用于宽线剖面、弯曲测线、传统的二维和目前广泛使用的三维地震观测 .在地形及近地表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 .本研究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 ,在三维空间重建近地表低降速带速度模型 ,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 .分析了复杂的近地表低降速带模型初至波的性质 ,在观测值的自动拾取以及理论值的计算中充分考虑了可能成为初至波的直达波、折射波和反射波的利用 ,提高了低降速带速度模型反演的精度 .在初至走时观测数据的拾取中 ,本研究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 .在射线路径与初至波理论走时的计算中 ,本研究采用一种计算量与模型复杂程度无关的三维射线追踪方法 ,该方法以最小走时射线路径保证了与观测数据有同等意义的初至波的射线追踪及理论走时的计算 .野外实际资料的处理结果表明了方法的有效性 .
Based on the model of surface consistency, a three-dimensional seismic observation that can be applied to wide-line profile, curved profile, traditional two-dimensional and widely used currently is proposed. , And the accuracy of low-velocity zone thickness and velocity estimation is the key to static correction.In this study, based on the first-arrival time-of-flight data of 3D seismic observation and the combination of least squares and QR decomposition, Band speed model, the synchronous calculation of long-wavelength components and short-wavelength components of static correction is realized based on the reconstruction velocity model.The properties of the first arrivals of the complex near-surface low-velocity model are analyzed, and when the observed values are picked up automatically and the theoretical values The calculation fully considers the use of direct wave, refracted wave and reflected wave that may become the first arrival wave, and improves the accuracy of inversion of velocity model with low down-speed.In the picking up of the first-arrival time observation data, the fractal algorithm Overcomes the difference between the waveform of the first arrival waveform and the pickup error caused by the phase reversal of the refracted wave, and realizes the large-scale full-automatic operation of the three-dimensional first arrival pick-up In the calculation of travel time and first arrival wave theory, this study uses a three-dimensional ray tracing method which has nothing to do with the computational complexity and model complexity. This method ensures the first-arrival wave with the same meaning as the observed data by the minimum travel time ray path Ray tracing and calculation of theoretical travel time.The results of field actual data show the effectiveness of the method.