Abstract: Presented are methods and systems for deghosting seismic trace data. A cost function and one or more applicable constraints are selected and used to generate a time-variant deghosting filter. The time-variant deghosting filter can be recalculated for predetermined time intervals over the span of the associated seismic data. The time-variant deghosting filter is then applied to the seismic trace data to attenuate ghosts within the predetermined time interval. A plurality of seismic trace data can be stacked before generating and applying the time-variant deghosting filter.

Abstract: Presented are methods and systems for deghosting seismic trace data. A cost function and one or more applicable constraints are selected and used to generate a time-variant deghosting filter. The time-variant deghosting filter can be recalculated for predetermined time intervals over the span of the associated seismic data. The time-variant deghosting filter is then applied to the seismic trace data to attenuate ghosts within the predetermined time interval. A plurality of seismic trace data can be stacked before generating and applying the time-variant deghosting filter.

Abstract: The invention relates to a method for determining ocean current using geophysical data acquisition means which are on board a ship, said ship towing at least one streamer which is equipped with at least one traction sensor and position measuring means. The invention is characterized in that it comprises the following steps, consisting in: collecting the measurements from said traction sensor, collecting the measurements from said position measuring means, repeatedly calculating a current vector that is representative of the real current by repeating the following operations using a given sampling time step: calculating simulated traction and streamer positioning data for numerous simulation input current vectors, comparing the simulated data to real measurements taken by said traction and position measuring means for each simulation input current vector. The invention also relates to a device used to carry out one such method.

Abstract: The invention concerns a cleaning process for an immersed and towed seismic streamer (1), characterised in that a cleaning appliance (11), including a tool for cleaning the seismic streamer, is engaged around the seismic streamer, together with a hydrodynamic drag structure which results in the free movement of the cleaning appliance along the length of the seismic streamer (1).

Abstract: The invention relates to a method of simulating the positioning of a streamer towed by a ship (10) during an operation of acquiring geophysical data at sea, said acquisition operation making use of shots from at least one sound source (Sa), the method implementing a hydrodynamic model of the interaction between marine current, the path of the ship, and the streamer, the method being characterized in that it includes determining variations in the current over time and in space. The invention also relates to a method of assisting navigation for a seismic survey ship, and to a method of predicting coverage fraction by implementing such a simulation method.