OBN OD technology records seismic waves propagated and reflected in oil reservoirs throughout seismic campaigns which, processed by supercomputers, improve prediction in new exploratory frontiers. Petrobras is beginning, for the first time in Brazil, the manufacture of on-demand ocean bottom nodes (OD OBN), used for seismic monitoring of offshore fields, especially in the pre-salt layer. What is OD OBN seismic? OD OBN technology records seismic waves propagated and reflected from oil reservoirs during seismic campaigns. Ideal for deep waters, 4D seismic, unlike traditional methods, reduces interference and improves image quality.