Method of imaging in an underground formations steep-sloping geologic interfaces, giving rise to prismatic reflections

摘要

Method of imaging in an underground formation one or more steep-sloping geologic interfaces, not necessarily plane, forming with primary reflectors, not necessarily plane, dihedra giving rise to prismatic seismic reflections (double reflections). The geometry of the steep-sloping interface is determined from a pick on seismic records of one or more events corresponding to prismatic reflections for different source-pickup pairs of an acquisition device. A new reflection tomography technique is used, wherein introduction of specific constraints allows to guarantee the convergence of the algorithm. The velocity distribution in the geologic formation and/or the geometry of the interface(s) between the sedimentary layers can be known otherwise or determined by means of the method. The method can apply to a formation comprising several different sloping interfaces.