Prestack Time Migration using the Kirchhoff Sum Along a New Approximation of the Reflection Travel Time Curve

This paper describes a new method whereby a better image of prestack migration is obtained. The core of the method is: 1.a new relation that expresses the location of the tangent point between the diffraction and between the reflection time curves as a function of the dip of the reflector 2. a new reflection travel time approximation in the vicinity of the tangent point, as a function of the dip and the radius of the curvature of the reflector. Choosing only the traces that contribute constructively, which are located in the vicinity of the tangent point, and stacking those along the approximated travel time curve a better image is obtained. The results of the testing show that using the new approximation of the travel time and stacking only traces in the vicinity of tangent point significantly improve the S /N ratio and an image that is superior to the image obtained by using the conventional Kirchhoff prestack time migration is expected