Abstract: The invention relates to a method for seismic survey by autonomous seismic nodes (1) at a sea floor (2), comprising: —attaching the seismic nodes (1) to a rope (3); —loading the rope (3) with the seismic nodes into a node deployer (4); —lowering the node deployer (4) into the sea (5); —towing the node deployer (4) above the sea floor (2); —deploying the rope (3) with the seismic nodes (1) at the sea floor (2); —collecting seismic data by the seismic nodes (1); —retrieving the rope (3) with the seismic nodes (1) from the sea floor (2), and —unloading seismic data from the seismic nodes (1). The invention also relates to a node deployer (4) for deploying a rope (3) with seismic nodes (1) at the sea floor (2), comprising a magazine (7) for the rope (3) with the seismic nodes (1).

Abstract: A method and apparatus for handling of sensor capsules and their inner components during deployment and retrieval of a seismic cable into the sea by a vessel where the seismic cable includes seismic node casings to contain the sensor capsules when the seismic cable is in the sea. The method includes the following steps: withdrawing a sensor capsule from a sensor capsule storage; withdrawing a battery unit from a battery unit storage; withdrawing a control unit from a docking station; combining the control unit and battery unit into a control/battery unit; inserting the control/battery unit into the sensor capsule and closing the sensor capsule; and loading the sensor capsule into a seismic node casing.

Abstract: An apparatus for storing control units comprises a cabinet (10) with a plurality of rails (41) arranged horizontally along inner sidewalls and is configured to receive a plurality of drawers (40) above each other. Each drawer (40) comprises a plurality of docking sockets (1), each docking socket (1) being configured to receive and retain one control unit. The apparatus comprises a robotic elevator device (20) adapted to move an elevator table (30) in a vertical direction to a vertical position corresponding to a pair of rails (41) into which a drawer (40) is to be inserted or from which the drawer (40) is to be withdrawn. The elevator table (30) comprises a linear motor (32, 34) capable of moving the drawer (40) along a pair of rails (41) in a longitudinal direction. A robotic gripper, which may be internal or external to the apparatus, is capable of putting control units into the docking sockets or withdrawing the control units from the docking sockets.

Abstract: A cleaning apparatus (100) for an ocean bottom cable (19) including a plurality of node casings (5), each containing at least one sensor capsule (9). During retrieval, an initial flushing device flushes the assembled cable with seawater before the capsules (9) are separated from the casings (5) in a loading/unloading apparatus (300). A washing tunnel (110) is configured to flush the sensor capsule (9) with water supplied from a freshwater tank (115) through a waterfeed pipe (117). Preferably, the cleaning apparatus also comprises a secondary flushing device for flushing the components with seawater after separation, and a drying tunnel (120). Separate conveyors convey the sensor capsules (9) and the node casings (5) to their respective destinations, such that each component may be flushed in seawater and/or freshwater and/or dried as required. The cleaning apparatus is optimized to use a minimum of freshwater and energy.

Abstract: An apparatus (100) for deploying and retrieving seismic nodes (200) comprises a towing connection (101) connecting the apparatus (100) to a towing cable (10) running from a towing vessel; vertical control means (125; 5; 120, 12) for adjusting a height over the seafloor by means of the towing cable (10); horizontal control means (125; 130-133) for adjusting a horizontal position according to the desired path and deployment and retrieval means (151; 160, 170, 180) for deploying and receiving nodes (200) connected to a wire (150) at predetermined intervals along the path. The deployment means are preferably configured to deploy the nodes (150) without substantial pull from the previously deployed wire (150).

Abstract: An apparatus and methods for loading and unloading of sensor capsules (9) into or out of seismic node casings (5) forming part of a seismic cable (19) to be deployed or retrieved by a vessel (18), the apparatus comprises: a trolley (3) with room for at least one sensor capsule (9), the trolley (3) is moveable back and forth in a direction essentially corresponding to the longitudinal direction (24, 25) of the seismic cable (19); a support structure (12) for the trolley (3); a latching mechanism (7) for latching the trolley (3) to a node casing (5), and at least one inserting/withdrawing mechanism (8, 11) for inserting and withdrawing the sensor capsules (9) into or out of the node casing (5).

Abstract: The invention relates to a seismic node (100), comprising at least one seismic sensor with associated electronics, a primary oscillator (106) for timing sensor signals, a reference oscillator (104), a memory, a power source, a switch (102) for turning the reference oscillator on and off, and a processor (112) for digitizing sensor signals and storing them in the memory, calibrating a frequency of the primary oscillator (106) based on the frequency of the reference oscillator (104), and turning the reference oscillator on and off.

Abstract: A method and apparatus for handling of sensor capsules and their inner components during deployment and retrieval of a seismic cable into the sea by a vessel where the seismic cable includes seismic node casings to contain the sensor capsules when the seismic cable is in the sea. The method includes the following steps: withdrawing a sensor capsule from a sensor capsule storage; withdrawing a battery unit from a battery unit storage; withdrawing a control unit from a docking station; combining the control unit and battery unit into a control/battery unit; inserting the control/battery unit into the sensor capsule and closing the sensor capsule; and loading the sensor capsule into a seismic node casing.

Abstract: The invention relates to a seismic node (100), comprising at least one seismic sensor with associated electronics, a primary oscillator (106) for timing sensor signals, a reference oscillator (104), a memory, a power source, a switch (102) for turning the reference oscillator on and off, and a processor (112) for digitizing sensor signals and storing them in the memory, calibrating a frequency of the primary oscillator (106) based on the frequency of the reference oscillator (104), and turning the reference oscillator on and off.

Abstract: An ocean bottom seismic cable recording apparatus comprising a plurality of seismic node casings (1), said node casings being separated from each other by separate stress member sections (2), each stress member section having acoustic decoupling arrangements (3) at each end connecting to said seismic node casings (1), and where each seismic node casing comprising an autonomous sensor capsule (5) for sensing and recording seismic data, and wherein the autonomous sensor capsule (5) is removable from said seismic node casing (1), and wherein each seismic node casing (1) further comprising an inner compartment (4) accommodating the autonomous sensor capsule (5).