Abstract：The essential factor of 3-D migration is extrapolation operator for 3-D wave field. Three-dimensional paraxial approximate equation with optimized coefficients can be obtained by using the equation,which has conjugate gradient method under least square a form of 45。 equation,can make wave migrate to natty stable and which have the correct position;and its difference equation 700 interface that is inexp premise.reflectionlict,etercentrally differential is constructed easily. 3-D migration equations standard form of 450 equation can be solved by adopting the difference equation.The algorithm has higher efficiency,better stability,and simpler programming than other algorithms for 3-D one pass migration.
