r_p/r_s在深度域为常数时,爆炸反射模型满足于零偏P—SV(转换波)数据。在垂向非均匀介质中,P—SV的绕射波近似于双曲线。在这种条件下可以推导出绕射点的偏移速度表达式。P—SV偏移速度比相应的rms(均方根)速度低6％～11％。对DMO校正后的合成P—SV叠加资料用一种传统的相移算法和导出的偏移速度做P—SV偏移,绕射波收敛,而使rms速度函数做偏移,则出现明显的过偏现象。 When r_p / r_s is a constant in the depth domain, the explosion reflection model is satisfied with the zero-bias P-SV (converted wave) data. In vertical inhomogeneous media, the diffracted wave of P-SV approximates a hyperbola. Under this condition, the expression of the deflection speed of the diffraction point can be deduced. The P-SV offset speed is 6% to 11% lower than the corresponding rms (root mean square) speed. The P-SV offset of DMO corrected P-SV superimposed data with a traditional phase-shift algorithm and the derived offset velocities converges and the rms velocity function shifts, then the obvious Over-bias phenomenon.