Abstract：In this paper,we present a new 2-D common-offset prestack time migration algorithm in frequency-wavenumber domain.The method generalized the formula of poststack phase-shift in zero-offset sections to that of prestack time migration in non-zero offset sections under the condition of constant velocity.The formulas are obtained by using numerical fitting method.This migration method can be suitable for vertically varying velocity by using an average velocity or stack velocity.Theoretically,these formulas are accurate only when velocity is constant.However,the synthetic and field data tests indicate that data with even reasonably rapid vertical velocity variation can be imaged effectively,and more important is also to significantly reduce the computational efforts.
