Downward continuation of marine seismic reflection data: an undervalued tool to improve velocity models

SUMMARY The purpose of marine seismic experiments is to provide information the structure and physical properties subsurface. P-wave velocity distribution most commonly modelled property, usually by inversion arrival times or waveform attributes. In wide-angle reflection/refraction (WAS) experiments, phases identified in data recorded ocean bottom seismometers (OBS) are used image relatively deep structures. Most WAS have low redundancy produce robust models limited resolution. shallow subsurface also studied with multichannel (MCS) towed streamers, a technique that highly complementary WAS. this case, recording refractions as first arrivals primarily streamer length features like water depth and, general, masked reflections noise. However, MCS variable quality available many regions where no other exist previous work has shown these can be retrieve through traveltime full provided properly extracted from record sections. widely tool extract recordings so-called downward continuation technique, which designed for redatuming field seafloor. new virtual configuration, early transform becoming visible nearly zero offset, facilitating their identification use tomography. there literature, let alone codes, sets. This presents user-friendly open source HPC software 2-D sea any seafloor relief. main ingredient acoustic wave equation backwards time, allowing receivers then sources. Assessment tools evaluate after specific acquisition configurations. Also, we present step-by-step analysis defines important influence virtual, redatumed recordings.