Abstract:
An apparatus includes a cable; and seismic sensors that are disposed in the cable. The apparatus also includes spacers that are distributed in the cable such that each seismic sensor is disposed in an interval of the cable separating a different adjacent pair of the spacers. The spacers of each pair are separated by at least twenty-five centimeters.
Abstract:
The invention is a marine geophysical sensor cable (1) with one or more sensor cable sections (2), - each of said sensor cable sections (2) provided with seimic and electromagnetic sensors (10, 20) arranged along said cable (1), - the seismic sensors (10) comprising a hydrophone (11) and a seismic component receiver (12) for seimic vector measurments while said sensor cable (1) being at the seafloor, - the electromagnetic sensors (20) comprising both E-field sensors (22) and H-field sensors (24) - said E-field sensors (22) comprising pairs of first and second electrodes (22a, 22b) arranged with different positions along the cable (1) and connected to a voltage amplifier (23), - The H-field sensors (24) comprising three mutually orthogonally arranged H-field component sensors (24x, 24y, 24z).
Abstract:
A production method for a headline sonar cable (20, 120) that exhibits a high breaking-strength and lighter weight than a conventional steel headline sonar cable. Producing the headline sonar cable (20, 120) is characterized by the steps of: a. providing an elongatable internally-located conductive structure (34, 134) that is adapted for data signal transmission; and b. braiding a strength-member jacket layer (52) of polymeric material around the structure (34, 134) while ensuring that the structure (34, 134) is slack when surrounded by the jacket layer (52).
Abstract:
A method includes recording a first set of data using a first type of sensor; recording a second set of data using a second type of sensor, the first and second sets of data being contemporaneously acquired by co-located sensors; and removing noise from the first data set using the second data set. An apparatus includes a survey vessel towing an array of towed streamers including a plurality of paired, co-located sensors densely distributed along the streamers. A first one of each sensor pair is of a first type and a second one of each sensor pair is of a second type. A computing apparatus records a first set of data acquire by the first type of sensor and a second data set acquire by the second type of sensor. The computing apparatus then removes noise from the first data set using the second data set.
Abstract:
A streamer or cable for use in subterranean surveying includes a communications link, a plurality of network nodes interconnected by the communications link, where each of the plurality of network nodes is configured to perform a self test to detect a fault condition of the corresponding network node, and bypass switches to bypass faulty one or more network nodes.
Abstract:
There is described an optical seismic cable (2) comprising a number of sensor units (5) spaced along the length of the cable and a number of connection units (4) spaced along the length of the cable, the cable further comprising a number of first optical fibres extending substantially continuously along the cable from one connection unit to the next, and a number of second optical fibres which each extend part-way along the cable between adjacent connection units, and wherein at each connection unit at least one first optical fibre is joined to a second optical fibre, and wherein at the sensor units sensors are joined to said second optical fibres. A second aspect of the invention provides an optical seismic cable module (3) comprising a number of first optical fibres extending substantially continuously from one end of the cable module to the other, and a number of second optical fibres which each extend part-way along the cable module, the seismic cable module further comprising at one end a connection unit at which at least one first optical fibre is joined to a second optical fibre, and a number of sensor units at which sensors are joined to second optical fibres.
Abstract:
An antenna system for capturing underwater sound waves comprising an optical fibre (3) making on one end a sensor member (5); and a controlled unwinding device (22) of the optical fibre carried by a dragging platform (10) and adapted to allow the entrance of the optical fibre in the water at an unwinding speed opposite to the advancement speed of the platform in order to minimise the hydrodynamic noise acting on the sensor member.
Abstract:
Bei einem Verfahren zur Herstellung einer Hydrofone (12) aufweisenden Antennensektion für eine aus mehreren Antennensektionen zusammensetzbare Unterwasserantenne werden die Hydrofone hintereinandergereiht in einen langgestreckten Hohlraum (20) im Abstand voneinander und zur Innenwand des Hohlraums eingebracht und wird der Hohlraum zur Fixierung der Hydrofone mit einem flüssigen Gel (19) gefüllt, das nach Einfüllen geliert. Zur fertigungstechnischen Vereinfachung des Einbringens und Positionierens der Hydrofone wird jedes Hydrofon mittels eines Saughebers (16) in dem mit seiner Längsachse im wesentlichen vertikal ausgerichteten Hohlraum im vorgegebenen Abstand von den zuvor eingesetzten Hydrofonen eingesetzt und gehalten. Anschliessend wird flüssiges Gel in dem Hohlraum in einer solchen Menge eingefüllt, dass das flüssige Gel das vom Saugheber gehaltene Hydrofon teilweise umschliesst. Nach Gelieren des eingefüllten Gels wird der Saugheber zum Einsetzen eines weiteren Hydrofons aus dem Hohlraum herausgezogen, wonach sich die Verfahrensschritte solange wiederholen, bis die vorgegebene Anzahl von Hydrofonen in dem Hohlraum platziert ist.
Abstract:
An anti-biofouling seismic streamer casing (100,100') is provided that is formed by a flexible tubing (110) coated with a layer of a two-part heat cured silicone elastomer (120). The seismic streamer casing (100, 100') is formed by a method that includes steps of providing a flexi+e tubing (200) and pre-treating the outer surface of the tubing (210). Two parts of a two-part silicone elastomer are then mixed together (220). The method also includes coating the mixed two-part silicone elastomer on the flexible tubing (230), and heating the flexi+e tubing to cure the coating (240).
Abstract:
The invention comprises a geophysical sensor apparatus for use under water in the sea, comprising a plurality of seismic sensors (1) for sensing seismic waves associated with underground formations, and a plurality of EM-sensors constituted preferably by electrodes (4) for sensing electromagnetic waves associated with said underground formations. In a preferred receiver cable configuration embodiment of the invention, the geophysical sensor apparatus comprises a seismic receiver cable with a linear array of a plurality of seismic sensors (1) and EM-sensors arranged inside a flexible outer skin (25), with said EM-sensors having electrodes on the outside of said outer skin. The cable is operated on the seafloor by a surface vessel, said vessel towing an electromagnetic transmitter antenna in addition to the seismic source.