Complex mountainous stepwise tomographic inversion modeling method Available to Purchase

Aiming at the problem of complex mountain modeling in western China, a stepwise tomographic inversion modeling method is studied for the requirements of pre-stack depth migration processing. The method consists of a series of measures to improve the surface accuracy, the near-surface model of shallow-middle layer and the model of deep layer step-by step. Surface: the terrain distortion caused by manual measured elevation interpolation is corrected by rebuilding the dramatic ravines terrain. Thus the ray path of tomographic inversion is completely propagated under the true-surface. Shallow-middle layer: the initial model of the tomographic inversion is established by the combination of up-hole and first breaks, and the segmented offset inversion is performed to match ray depth with the thickness of the LVL. The error caused by the shallow depth of up-hole survey and the mismatch of offset range are eliminated. And then the high-accuracy LVL velocity model is established. Deep layer: on the basis of embedding LVL velocity model, “logging velocity constraint + full offset” is used to obtain the deep velocity information under LVL. It can provide a high-accuracy velocity field for pre-stack depth migration processing. The effectiveness of the method is demonstrated by the application of the complex area of Yingxiong Mountain in Qaidam Basin, China.