Kietta

Luc Haumonte

Michel G Manin

Laurent Velay

Divine Maalouf

Denis Greffet

A seismic marine vibrator () may comprises first plates () and second plates () arranged along a longitudinal axis (), longitudinal and peripheral first () and second () elements respectively secured to the first () and second () plates, and an actuator () operable to reciprocate the first elements () relative to the second elements () along the longitudinal axis () so as to reciprocate the first plates () relative to the second plates (). The seismic marine vibrator further comprises peripherally closed air-filled chambers () and peripherally open chambers (), the volume of said open chambers () being varied when the first plates () are reciprocated so as to take in and expel water radially to generate an acoustic wave. This forms an improved seismic marine vibrator.

Seismic marine vibrator

The invention notably relates to a method for controlling depth of a seismic cable having ballasts spaced apart along its length and providing a neutral buoyancy to the seismic cable, the seismic cable being adapted for midwater data acquisition, each end of the seismic cable being connected to a respective surface autonomous vessel exerting tension on the cable through a respective lead-in cable having a negative buoyancy, the method comprising, with respect to a target depth, varying the deployed length of each lead-in cable and/or the tension exerted on the cable by each respective surface autonomous vessel. This provides an improved solution for seismic prospecting in aquatic mediums.

Controlling the depth of a seismic cable

The invention in particular relates to a method for controlling the horizontal position of a seismic cable adapted for acquiring seismic data midwater. The method comprises, based on a deviation observed between the position of the seismic cable and a setpoint horizontal position, a correction of the position of the seismic cable through an adjustment of the forces respectively exerted by lead-in cables on the ends of the seismic cable, the exerted forces simultaneously and each having an axial component and a lateral component relative to the seismic cable at at least one moment of the correction. This allows an easy to implement and relatively precise control of the horizontal position of a seismic cable adapted for acquiring seismic data midwater and kept stationary or quasi-stationary during the data acquisition.

Control of the horizontal position of a seismic cable

The invention notably relates to a water surface autonomous vessel having a hull and configured to be connected, through a lead-in cable having a negative buoyancy, to an end of a seismic cable having a neutral buoyancy and adapted for midwater data acquisition, wherein the water surface autonomous vessel comprises a winch for varying the deployed length of the lead-in cable, and the hull of the autonomous vessel forms a conduct at the back of the autonomous vessel in the direction of deployment of the lead-in cable. This provides an improved solution for seismic prospecting in aquatic mediums.

Water surface autonomous vessel

A method is proposed for acquiring seismic data relative to an area of the subsoil, wherein at least one seismic source is moved and seismic waves are emitted in successive shooting positions of the source so as to illuminate said area of the subsoil, and the signals resulting from this emissions are picked up using a set of cables having a substantially zero buoyancy and provided with receivers. The cables have a substantially zero speed or a speed substantially slower than the source in the terrestrial reference frame. And said successive shot positions are determined as a function of the position of the receivers relative to the terrestrial reference frame to optimize at least one quality criterion relating to the set of seismic signals acquired by the receivers in respect of said area. Such a method enables improved seismic data acquisition.

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Marseilles, France

Luc Haumonte