A new kinematic method for mapping seismic reflectors

This paper presents a modern version of an old technique of common tangent reflection migration. Rather than using the graphical method of swinging arcs and looking for the envelope of touching tangents on widely separated geophones, we use a numerical scheme of searching along each isochron, constructed by a wave-equation-based modeling scheme for arbitrary velocity media, to find the common tangent points. The assumption is made that the receivers are close together so that the interface can be locally approximated by a straight line, although different pairs of receivers permit different tangents to be found, enabling a curved boundary to be migrated. The technique can be extended to several shot gathers to map multiple curved boundaries. Synthetic examples are used to illustrate the capabilities of the method and the effect of using an erroneous velocity distribution.