Time reversal based detection of subsurface scatterers

Conventional seismic migration and inversion are inherently limited in their ability to detect and delineate small scale elements such as faults, pinchouts, karsts, fractures, fluid contact etc. However, those elements, smaller than the seismic wavelength, act as scattering points which can be effectively positioned using the time reversal (TR) principle. In this study, TR is used to spatially localize subsurface sources in passive seismic scenarios and scatterers in active seismic surveys, both having physical properties of a diffractor. The method uses back propagation of the time-reversed registered wavefield followed by analysis of the obtained focusing, based on a supervised learning approach. It doesn't include application of any imaging condition nor requires knowledge of the source wavelet and accounts for multiple scattering. The usefulness of the method is demonstrated on both synthetic and field examples.