用旅行时反演确定层速度的横向变化

本文用叠前共炮点或共中心点道集记录的反射波旅行时反演来确定目的层层速度的横向变化。采用正演模型的旅行时与实测旅行时最佳拟合的方法求取层速度参量,这种方法与地震反射波层析技术是一致的。但常规的地震反射波层析技术求解的参数多,使得计算结果不稳定,且具有多解性。本文采用了一些措施,如选用合理的地质模型及等效层的方法和平衡雅可比矩阵元素的方法等,力求减少反演的参数,稳定了求解过程和提高了求解的精度。在实际应用上取得了良好的效果。另外,文中还论述了旅行时反演原理和有关的技术问题,并给出了工作流程。最后介绍了该方法在大庆地区对地震资料进行反演的实际例子。

Determination of lateral intervalvelocity variation using travel time inversion.

Lateral interval-velocity variation in a target stratum can be determined by performing travel time inversion of prestack common-shot gathers (or common-midpoint gathers). Interval velocities are evaluated by minimizing the difference between observed travel time and travel time derived from forward modeling. Ideally, this method is identical with seismio reflection tomography, which, however, involves more parameters, so that inversion process is unstable,and solution multiple. Some measures, such as reasonable geological model, equivalent layer and equalization of Jacobi matrix elements,are taken to achieve less parameters, stable inversion j process and definite solution. Good results have been obtained in the practice. Travel time inversion principle and relevant technical problems. are discussed, and work steps given. The example is given of applying this method to Daqing seismic data inversion.