The presently disclosed technology relates to an arrangement for seismic acquisition where the spacing between adjacent pairs of receiver and sources lines is not all the same. Some receiver and/or source lines and/or receiver and/or source spacings are larger and some are smaller to provide a higher quality wavefield reconstruction when covering a larger total area or for a similar total area of seismic data acquisition, while providing a wavefield that is optimally sampled by the receivers and sources so that the wavefield reconstruction is suitable for subsurface imaging needs.

Method and streamer connecting module for connecting streamer sections to each other. The streamer connecting module includes a housing extending along a longitudinal axis (L) so that first and second ends are opposite to each other; a first streamer connecting part fixedly attached at the first end of the housing; a second streamer connecting part fixedly attached at the second end of the housing; first plural balls located between the first streamer connecting part and the first end of the housing; and a first conduit formed at an interface between the first streamer connecting part and the first end of the housing for accommodating the first plural balls.

A marine array having various embodiments of a modular foil system is disclosed. The modular foil system may be configured to generate lift when towed in a marine environment, and thus used to move, position, and/or depress instrument of the array. The modular foil system may include multiple groups of foil sections, each having an angle of attack that is adjustable relative to other groups of foil sections. For example, each group may be supported by a pair of through cables, and an actuator may adjust a tension in one or both of through cables, thereby alerting the angle of attack. The pair of through cables may converge toward one another at connection points adjacent opposing ends of a given group of foil sections of the modular system. The connection points thus establishing a modular framework to couple the given group to other groups of foils of the system.

A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source (e.g., air gun array) of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and the source. A floatation device supports the source and tows below the water's surface to avoid ice floes or other issues encountered at the water's surface. Seismic streamers have head floats supporting the streamers. Each of the floats has adjustable buoyancy preconfigured to counterbalance the weight in water of the towed component that the float supports. Acoustic signals from a transceiver at the vessel find locations of the towed components. A towed fish at a lower level than the towed components also uses acoustic signals with a transceiver to further refine the locations of the towed components.

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.

A retriever system for retrieving a marine equipment. The retriever system comprises a hollow body having a first opening, a cap adapted to close the first opening of the hollow body and adapted to be removed. A buoyancy assembly housed in the hollow body and adapted to exit the hollow body when the cap is removed. A linkage system maintains the buoyancy assembly linked to the hollow body of the retriever system. The buoyancy assembly comprises first inflatable element and a second inflatable element, and an inflating system configured to, when activated, inflate the first inflatable element, so as to enable exiting of at least the second inflatable element of the buoyancy assembly out of the hollow body. Said inflating system is configured to start or to continue inflating the second inflatable element when said second inflatable element is out of the hollow body.

A foil for a towed cable includes a body defining at least two conduits. The body has a foil shape having a leading edge and a trailing edge. The foil shape defines a first surface extending between the leading edge and the trailing edge configured to provide lift. The foil shape defines a second surface opposed to the first surface extending between the leading edge and the trailing edge. The foil shape defines first and second lateral sides that extend between respective lateral edges of the first and second surfaces, the leading edge, and the trailing edge. A first conduit is defined within the forward half of the body adjacent to the leading edge, is open to each of the first and second lateral sides, and is configured to receive a cable therethrough. A second conduit may be defined within the body and filled with buoyant material.

A seismic data acquisition system includes a streamer spread including plural streamers that extend along an inline direction X; a set of front sources that are positioned ahead of the streamer spread along the inline direction X; and a set of top sources that are positioned on top of the streamer spread, along a horizontal direction that is perpendicular to the inline direction X. A characteristic of the set of front sources is different from a characteristic of the set of top sources, and bins corresponding to collected seismic data from each source set are interleaved.

A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and source. A floatation device supports the source and tows below the water's surface to avoid ice floes. The streamers can have vehicles deployed thereon for controlling a position on the streamer. To facilitate locating the streamers, these vehicles on the streamers can be brought to the surface when clear of ice floes so that GPS readings can be obtained and communicated to a control system. After obtaining readings, the vehicles can be floated back under the surface. Deploying, using, and retrieving the system accounts for ice at the surface in icy regions. In addition, handling the seismic record can account for noise generated by ice impact events.

An arrangement for remotely controlling the position of a trawl door (1) or deflector for seismic surveys comprises an attachment point provided on a movable part (10). The movable part (10) can be moved in relation to a body of the trawl door (1) by means of a remotely controlled actuator. The movable part (10) with the attachment point (15) for a towing line is provided at the body or at a centre rib of the body of the trawl door (1). The movable part (10) with the attachment point can be moved substantially in vertical direction and approximately at right angles in relation to the direction of movement of the trawl door (1) when operated at sea, thereby resulting in an upwards or downwards movement of the trawl door (1) and thereby providing continuous adjustment of depth at which the trawl door (1) operates in the water.