Abstract：In view of difficulty of structural mapping in low-amplitude structural area of Tarim basin,the paper presented relevant velocity field-building and velocity-varying mapping method;Using horizon-oriented velocity analytic technique to improve the lateral resolution of stack velocity;using stack velocity or raw prestack gathers for input inverted interval velocity the former does not have restriction of such preconditions as horizontal layered medium and ray vertical incidence,having better adaptability to complex attitude of layer,the later overcomes the influence of precision of stack velocity,having higher precision;using stack velocity mis-tie correction and msr(mean-square-root) velocity mis-tie correction to get relatively precise velocity field,which is appropriate to be used for 3-D time-depth conversion;finding distributive rule of depth error after studying the correlation of depth error with time,velocity and buried depth,the second correction of structural map is further carried out.Comparing with traditional straight ray mapping technique,the method can greatly improve the precision of structural map in depth domain in low-amplitude structural area.
