Streamer for seismic prospection comprising tilt compensation of directional sensors

A streamer for seismic prospection comprising directional sensors (20), such as geophones or accelerometers, distributed along the streamer, said streamer comprising:

• at least two tilt sensors (30, 40) located regularly along the streamer in remote positions and in locations distant from the directional sensors, the distance between two successive sensors (30,40) being such that the torsion produced by normal operation of the streamer does not induce more than 360° rotation between two successive sensors, compared to the normal relative position of the at least two successive tilt sensors (30,40) when not subject to any torque;
• and
• a processor configured to determine a tilt detected by each of the at least two tilt sensors (30,40), interpolating the tilt detected by the at least two tilt sensors along the streamer so as to define by interpolation a tilt of the streamer at the location of each directional sensor and determining that the effective orientation of each directional sensor (20) is equal to the tilt of the streamer defined at the location of each directional sensor by interpolating along the streamer the tilt detected by the at least two tilt sensors (30, 40), characterized in that said streamer further comprises an auxiliary processor configured to determine the orientation of a first wavefield received on one of said directional sensors (20) and which determines the effective orientation of each directional sensor (20) from the orientation of this first wavefield, wherein the orientation of the directional sensor (20) resulting from the interpolation along the streamer of the tilt detected by the at least two tilt sensors (30, 40) is corrected using a difference between the theoretical value obtained with interpolation of the relative orientation between the at least two tilt sensors (30, 40) and the value estimated by the orientation of the first wavefield,
• wherein the auxiliary processor is configured to:
• detect the occurrence of a first arrival in a seismic signal issued by a hydrophone or a particle motion sensor;
• extract from the signals issued by a directional sensor, such as a particle motion sensor (20), a signal window around the timing of the first arrival detected;
• measure the root mean square of the projection of the signals issued by the directional sensor on each direction of the plane or space;
• determine the orientation of the maximum computed root mean square value and considering this orientation as the direction of the first arrival wave.