Abstract: In order to accumulate data from which the signature of an array of n interacting seismic sources 21 to 27, for instance marine seismic sources in the form of air guns, can be determined, the array is actuated and the emitted pressure wave is measured at n independent points whose positions will respect to the array are known by hydrophones 31 to 37. Data from the measured pressure wave is stored for subsequent processing to produce n equivalent signatures of the n sources taking into account the interactions therebetween. The signature of the array is then determined merely by superposing the n equivalent signatures.

Abstract: Air guns to be fired in water for carrying out seismic prospecting of the sea bed are suspended from a single rigid buoyant-body pararane so that the position of the air guns in the water is not unfavorably influenced by wave movements on the water surface.

Abstract: A float for use in seismic surveys of the sea bed supports a plurality of seismic pulse transmitters (6) which are suspended on lines (7) beneath the float (1). At a distance from the front end of the float (1), on one sidewall thereof, a fastening device for a towing cable and a lead-in for control lines and lines for supplying operating medium to the pulse transmitters are provided. These lines and cables are gathered in a common line (3) which extends behind the tow ship. The line (3), at a distance away from the float (1), is connected to a line (4) which leads to a length-regulating device (12) inside the front section of the float. The float is also provided with at least one motor (10) with a drive shaft (9)leading to hoisting drums (8) for the lines (7) to the respective seismic pulse transmitters (6). Both the motors (10, 12) and the seismic pulse transmitters (6) are connected to the pneumatic supply line.

Abstract: A method for the reduction of data logging in seismic data processing, in which data are transmitted between a plurality of data acquisition devices with a plurality of channels and a central receiving and recording device by using a plurality of transmission modules each of which is essentially allocated to a date acquisition device and each channel is assigned corresponding seismic traces comprises, providing real physical seismic traces and synthetic seismic traces, inserting the synthetic traces between the real traces, locating the seismic traces with relative uniform, physical distance, assigning corresponding simulated channels to the synthetic traces, assigning to each simulated channel an estimate of the real value for a corresponding physical channel, and adapting each estimated value to the values of at least one adjacent physical channel assigned the corresponding real physical traces.

Abstract: A float for use in seismic surveys of the sea bed supports a plurality of seismic pulse transmitters (6) which are suspended on lines (7) beneath the float (1). At a distance from the front end of the float (1), on one sidewall thereof, a fastening device for a towing cable and a lead-in for control lines and lines for supplying operating medium to the pulse transmitters are provided. These lines and cables are gathered in a common line (3) which extends behind the tow ship. The line (3), at a distance away from the float (1), is connected to a line (4) which leads to a length-regulating device (12) inside the front section of the float. The float is also provided with at least one motor (10) with a drive shaft (9) leading to hoisting drums (8) for the lines (7) to the respective seismic pulse transmitters (6). Both the motors (10, 12) and the seismic pulse transmitters (6) are connected to the pneumatic supply line.

Abstract: An assembly for use in seismic surveys of the sea bed is towed behind a vessel and comprises groups of seismic signal transmitters which are towed through the water, being suspended from float buoys which are combined to form one body which may be formed as a sleeve having limited flexibility. The body is formed with a head member shaped for reducing resistance to the water, and connected to a coupling point for a tow wire to the vessel, which point lies forward of the head member and at the same depth as the transmitters.

Abstract: An arrangement in a piezoelectric hydrophone that is provided with a protective outer housing enveloping a waterproof closed casing (2). Said casing is provided with two mutually opposed and parallel diaphragm wafers (3) on the insides of which piezoelectric crystals (4) being metal coated on their outsides are respectively attached. A connecting wire is extended from said case through its hollow central portion (6). Said central portion (6) is formed by at least two ceramic elements (7) joined along a plane parallel with the diaphragm wafers and provided with a metalization (11) in the mutual contact areas (9, 10). In the cavities (12) respectively of the two elements (7) stiffening ceramic disks (8) are provided and attached to the elements (7) by the aid of a matching projection (13). The inward facing poles of the piezoelectric crystals are conductively connected with the metalization in the contact plane of the elements, and an additional wire (5) is provided from the metalization (11) on the outside.

Abstract: A cable for towing air or water guns behind a seismic vessel is constructed with a reinforced air hose in the center region. The air hose (1) is a Kevlar fiber reinforced high pressure air hose with low air diffusion. Outside the hose, signal conductors are placed which are individually insulated with watertight coating and arranged substantially in a single layer of cylindrical elements (2) that are wound around the air hose (1). The interstices between the elements are filled with a water-repelling lubricant. Outside the layer of cylindrical elements (2) is a protective intermediate jacket (3) not intended primarily to have a water-sealing effect, and this is followed by tension-relieving elements (4) preferably disposed in two layers twisted in opposite directions around the intermediate jacket. An outer protective jacket (5) for the entire cable can be provided on the exterior. A cable constructed in this way provides a solution of the water-sealing problem.

Abstract: A means for terminating of splicing a cable intended for towing air-water guns behind a seismic vessel. The end of the cable, or of each cable section, is guided into the housing of the termination member. The termination is formed with separately located connection sites for the cable components. The cable's tension-relieving wires (3) are guided into a first chamber (I) in the housing and fastened to the supporting structure of the chamber (I), i.e., the housing. The chamber (I) is filled with a water-repellant lubricant. The cable's conductors (9) are guided individually through the first chamber (I) and through a sealed passage (10) in a wall (14) defining a second, watertight chamber (II) which is filled with an electrically insulating, hydrophobic, water-emulsifying liquid. The chamber (II) is also provided with a pressure compensator (8).

Abstract: A system for sorting data from seismic surveys at sea. The data are acquired by signal transmission/receiving by streamer cables, which streamers are equipped with position-defining instruments. For the sorting, the area to be surveyed is subdivided into squares of defined size and position. The data provided through the measurements is sorted, and accepted data is processed further and transferred to the individual squares in the grid pattern. On the basis of the data, the configuration and position of the streamer is also computed, and information regarding this is displayed on a screen. On the basis of these results, the coverage of the measurement area may be determined, and an adjustment of the vessel's steering can be carried out to allow one to obtain the best coverage of the area. The acquired data is stored for later treatment.

Abstract: The present invention relates to a float which is provided with at least one hoist drum for a hoisting wire from a hoist. The float is provided with at least one suspension drum for a suspension wire to a suspension body. The hoisting drum and the suspension drum are rotationally coupled to each other and the wires are arranged in such a way on the drums that the suspension wires are reeled in when the hoisting wires are reeled off the hoisting drums and vice versa.

Abstract: A method and apparatus for use in marine seismic data gathering comprises a vessel (1) is equipped for deploying and retrieving trailer cables and tows a plurality of cables (3) which are provided with at least one array of transmitters (5), which array constitutes a point source for a transmitter, and an acoustic cable, over the region to be investigated. The transmitter cables (3) are caused to become distributed laterally in relation to the tow direction, the distance between them, the firing power and firing timing being controlled from the vessel in accordance with data collected previously regarding the nature of the sea bed. The point source-formed transmitter arrays can be distributed both laterally and longitudinally in relation to the tow direction. The transmitter cables (3) are distributed laterally with the aid of otterboards (8).