Abstract：According to the distribution characteristics of point source diffraction wave field, a source and geophone array design method for prestack migration is proposed in the paper. The expressions of the time change rate at the source array center along its direction as well as that at the geophone array center along its direction are derived. Meanwhile the amplitude suppression characteristics of diffraction wave is obtained when the shot-to-geophone-distance vector direction, offset vector direction, source array direction and geophone array direction are the same, and when maximum time difference occurs within source array and geophone array. The relationship between array length and high cut frequency of reflection and diffraction is also discussed in the paper. Finally a quantitative calculation method of array length for pre-stack migration is put forward.
