Imaging steep-sloping geologic interfaces using prismatic reflections

摘要

A method of imaging, in an underground formation, one or more steep sloping geologic interfaces F which form with primary reflectors Rp faces of a dihedron which give rise to prismatic reflections (double reflections). The faces of the dihedron are not necessarily plane. The geometry of the steep sloping interface is determined by picking on seismic records the arrival times of events corresponding to prismatic reflections for various source receiver pairs. A reflection traveltime tomography technique is used which comprises constraints to guarantee the convergence of the algorithm. The velocity distribution in the geologic formation and/or the geometry of the interfaces between the sedimentary layers can be known or can be determined by the method. The method can apply to a formation comprising several different sloping interfaces.