【摘要】 理论和实践证明，三维叠前深度偏移是目前最精确的地震波场成像方法。该文在二维叠前深度偏移及偏移速度模型建立方法研究的基础上，进一步研究了变范围三维叠前深度偏移叠加方法和软件。用三维相移加校正方法在炮集上实现三维叠前深度偏移，并根据三维速度模型构造形态，自动确定偏移后成像孔径进行变范围偏移叠加，提高三维构造形态清晰度。该方法属全波动方程偏移，具有成像精度高，对模型适应性强的特点更多还原

【Abstract】 The theory and practice prove that prestack depth migration is the most accurate imaging method of seismic wavefield at present. Based on 2 D prestack depth migration and the creation of migration velocity model , the authors have studied and realized the method and software of variable range 3 D prestack depth migration . The migration imaging range is determined according to the structural attitude of 3 D velocity model , and the variable range 3 D prestack depth migration is done on the CSP gathers by phase shift plus correction . The migrated structural feature is more distinct. The method is a kind of full wave equation migration and is characterized by the high wavefield imaging precision and good adaptation to the models.更多还原