Sercel Inc.

Simon Leboeuf

Gaetan Mellier

Mike Maples

John S Hepp

Isabelle Sellin

Alexis Duboue

Gaëtan Mellier

Alexis Duboué

Noël Voisin

John Hepp

A method for rotating recorded seismic data. The method includes receiving raw seismic data recorded with a particle motion sensor located along a streamer; receiving vibrational data recorded by a gravity sensing sensor also located along the streamer; calculating an angle &#x3b2;(t), defined by a Z axis of the particle motion sensor and a Zaxis of a global orthogonal system of coordinates, based on (1) an angle &#x3b1;(t), defined by a Zaxis of the gravity sensing sensor and the Zaxis, and (2) an angle &#x3b8;(t) defined by the Zaxis and the Z axis, wherein the Z axis is part of a first local orthogonal system of coordinates attached to the particle motion sensor, the Zaxis is part of a global orthogonal system of coordinates attached to the earth, and the Zaxis is part of a second local orthogonal system of coordinates attached to the gravity sensing sensor; and correcting the raw seismic data by rotating the raw seismic data, recorded in the first local orthogonal system of coordinates, with the angle &#x3b2;(t), to obtain corrected seismic data in the global orthogonal system of coordinates. The first and second local system of coordinates share a same X axis but the other two axes of each of the first and second local systems are offset from each other by angle &#x3b8;(t) while the streamer moves in water and records the raw seismic data and the vibrational data. The global orthogonal system of coordinates share the same X axis with the first and second local systems, and the global orthogonal system is fixed to the earth while the first and second local systems rotate with the streamer.

Seismic data tilt angle correction method and system for multisensor streamer

A method for calculating a tension (T) in a towed antenna. The method includes towing the antenna in water, wherein the antenna includes plural particle motion sensors distributed along the antenna; measuring with the plural particle motion sensors vibrations that propagate along the antenna; calculating a value of a phase velocity (vp) of the vibrations that propagate along the antenna based on (1) an offset between two particle motion sensors and (2) a time delay of the vibrations that propagate from one of the two particle motion sensors to another one of the two particle motion sensors; selecting a relation that links the phase velocity (vp) to the tension (T); and using the value of the phase velocity and the relation to determine the tension (T) at various locations of the plural particle motion sensors along the antenna.

Tension monitoring method and system for towed antenna

A method for estimating a tilt angle &#x3b2;(t) of at least one given particle motion sensor nearly collocated, in a multi-sensor streamer for seismic prospection, with a pressure sensor. The given particle motion sensor has two orthogonal sensing axes Y and Z in a plane orthogonal to a longitudinal axis of the streamer. The tilt angle is formed by the Z sensing axis and a reference vertical axis Z. The method comprises, for the given particle motion sensor, a step of computing a first estimate &#x3b2;of the tilt angle, comprising, while the streamer is being towed: obtaining () first data measured by the pressure sensor nearly collocated with the given particle motion sensor; obtaining () second and third data measured by the given particle motion sensor along the sensing axes Y and Z respectively; for at least two values of a rotation angle &#x3b8;, rotating () the second and third data by the rotation angle &#x3b8;, to obtain rotated second and third data; and computing (-) a particular value &#x3b8;among the at least two values of the rotation angle, which maximizes, over at least one frequency, a coherence function between the first data and the rotated third data, or between the first data and velocity data resulting from an integration of the rotated third data, the particular value &#x3b8;being equal to said first estimate &#x3b2;. Step of computing a first estimate &#x3b2;of said tilt angle is processed independently of any seismic signal.

Method for tilt (roll) and pitch estimation in a multi-sensor streamer

A seismic detection line includes one or more identified element(s) arranged in a string, and a telemetry link connecting the element(s) along the string to convey seismic data from at least one of the element(s) to a data recorder and identification data to a topology controller. Each of the element(s) includes a respective first identification unit connected to the telemetry link to provide a respective first identifier to the topology controller. A seismic detection system also includes a processor that queries the identified element(s) for their respective identifiers, determines an arrangement of the seismic detection line using the received identifiers, and presents an indication of the determined arrangement. A method of operating a seismic detection line includes transmitting a query along the telemetry link, detecting whether the respective identifier of one of the element(s) was received or not, repeating until termination, and determining and indicating the arrangement.

Seismic detection line having identified element and method

A streamer for seismic prospection comprising directional sensors (), such as geophones or accelerometers, distributed along the streamer, characterized in that said streamer comprises at least two tilt sensors () located in remote positions and in locations distant from the directional sensors () and means which determined the effective orientation of each directional sensor () by interpolating along the streamer the tilt detected by the two tilt sensors ().

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Monnieres, France

Simon Leboeuf