Abstract：The paper describes a new three-dimensional wave equation P-R splitting migration-three-dimensional P-R splitting migration using directional derivative. In this method, a special parallelogram grid and the corresponding difference scheme in Clearbout's floating time coordinate system are used to approximate the second order partial derivatives of the equation with respect to τ and t (directional derivatives), without any prior approximation of three-dimensional wave direction. Finally, we can obtain a three-dimensional difference equation that is formally similar to the equation for 15º P-R splitting migration. This method is more practical than others because it can achieve all-dip migration of full waves at all azimuths, only needs the calculation equivalent to that for 15º three-dimensional P-R splitting migration, and avoids the troubles that 15º three-dimensional P-R splitting migration is only applicable to small dip formations and that all dip three-dimensional P-R migration in 45º rotational coordinate system needs more calculation.
