Abstract: A seismic survey system is provided. The system can include a source array including a first sub-source array and a second sub-source array. The system can include a streamer coupled with the first sub-source array and a streamer coupled with the second sub-source array. The system can include a receiver array including a plurality of receivers. The system can include a lateral cable coupled with at least one of a first diverter or a second diverter and at least one of the first sub-source array or the second sub-source array. The system can include a positioning cable coupled with the first diverter and a positioning cable coupled with the second diverter. The system can include a power cable. The system can include a seismic data acquisition unit array including a plurality of seismic data acquisition units disposed on a seabed.

Abstract: A print head is disclosed for use with an additive manufacturing system. The print head may include a matrix reservoir configured to hold a supply of matrix, and a flop guide located within the matrix reservoir. The flop guide may be configured to at least partially surround a continuous reinforcement passing through the matrix reservoir. The print head may also include a nozzle connected to an end of the matrix reservoir downstream of the flop guide.

Abstract: Vented optical tube. At least some illustrative embodiments are conduits comprising a tube having a wall defining an interior volume of the tube. One or more optical fibers are disposed within the interior volume. The wall includes a plurality of vents passing from an outer surface of the wall to the interior volume, the plurality of vents disposed along a length of the tube, and wherein the vents are configured to convey a fluid in contact with the outer surface into the interior volume of the tube.

Abstract: A method for deploying a payload into a body of water using a deployment vessel, the deployment vessel including a hull defining a payload compartment, the method including positioning the payload in the payload compartment of the deployment vessel, the deployment vessel and the payload having a buoyancy, wherein the buoyancy is initially negative, deploying the deployment vessel into the water at a drop zone, wherein the deployment vessel moves horizontally through the water as it submerges vertically downward under a force of gravity, changing the buoyancy to positive after a minimum horizontal distance is established between the drop zone and the deployment vessel, thereby causing the deployment vessel to surface and, after the surfacing of the deployment vessel, opening the hull to release the payload therefrom.

Abstract: Control device (10, 20) for controlling the position of an instrumented cable towed in water, such as a marine seismic streamer, and/or an instrumented towed cable array (streamer array), which control device (10, 20) is provided with buoyancy means (30) for retrieving the control device (10, 20) and instrumented cable to the surface, at least sections of the instrumented cable, which means (30) are arranged for providing the control device (10, 20) with buoyancy.

Abstract: One embodiment of the invention concerns a probe that couples to a seismic vessel via a tow cable. When deploying probes from a seismic vessel that is towing source arrays and streamers, the probe and its tow cable can tangle with elements of the towed seismic spread. However, a cable guide may be used to lessen the risk for such entanglement by guiding the tow cable into the water at a distance removed from the seismic spread. Also, the probe may be steerable to steer the probe and tow cable away from the seismic spread. Other embodiments are described herein.

Abstract: Retriever systems for marine geophysical survey sensor streamers. At least some of the illustrative embodiments are methods including attaching a retriever system to a sensor streamer by: wrapping a lifting bag assembly at least partially around the sensor streamer, the lifting bag assembly comprising a deflated lifting bag, a gas cylinder, and a depth trigger mechanism; and covering the lifting bag assembly with an outer cover.

Abstract: A method for water monitoring about a deviated well is disclosed. The method includes positioning a series of electromagnetic (EM) receivers in a completed deviated wellbore, said receivers being spaced along substantially the length of the well located in a region of a reservoir to be monitored. The method also includes positioning an electromagnetic (EM) source at a first Earth surface location. Then the EM source is activated for a first survey measurement of the reservoir, and an EM field detected at each EM receiver is recorded. The EM source is moved to a second Earth surface location, and activated for a second survey measurement of the reservoir, and an EM field detected at each EM receiver is recorded. From the first and second survey measurements at each of the receivers, an inversion is performed to determine position of water about (and specifically below) the horizontal well.

Abstract: An activation module to be used in a seismic equipment recovery device. The activation module includes a processor; a pressure transducer configured to measure a pressure of the ambient and provide the measured pressure to the processor; a memory connected to the processor and configured to store information related to a pressure or depth threshold; and a communication unit connected to the memory and configured to exchange information with an external device. The processor is configured to send a deployment instruction to an inflation mechanism to inflate a flotation bag based on the measured pressure and the stored information.

Abstract: A source array generates seismic waves in water during a marine seismic survey. The source array includes a first sub-array including plural source elements; plural acoustic transceivers distributed along the first sub-array; a positioning system; a primary position control device configured to control a position of the first sub-array; and a secondary position control system configured to adjust a depth of the first sub-array.

Abstract: A compound buoy. At least some of the illustrative embodiments are buoy systems that include: a surface buoy; a subsurface buoy comprising an elongated outer body; a connector disposed on the lower surface; and a winch having a line, the line coupled between the surface buoy and the subsurface buoy. The buoy system has first configuration in which the upper surface of the subsurface buoy abuts the surface buoy, the abutting relationship held by tension in the line, and the buoy system has a second configuration where a distance between the surface buoy and the subsurface is limited by a length of the line spooled off the winch. In operation, the subsurface buoy supports more of the subsurface load than the surface buoy.

Abstract: A seismic acquisition system. The seismic acquisition system may include at least one unmanned water vehicle. The seismic acquisition system may also include at least one seismic streamer coupled to the at least one unmanned water vehicle, where the at least one seismic streamer has one or more seismic sensors coupled thereto for recording seismic data in a survey area. The seismic acquisition system may further include a buoyancy compensation mechanism coupled to the at least one seismic streamer, where the buoyancy compensation mechanism is configured to orient the at least one seismic streamer between a generally vertical direction and a generally horizontal direction through a water column.

Abstract: A system includes a plurality of streamers (towed acoustic linear antennas), each cooperating with a set of at least one depth control element having a determined diving capability enabling to immerse the tail of the streamer. At least one given streamer has a tail connected to a tail device which is a towfish device including a flotation body and a satellite navigation system receiver including an antenna fixed on the flotation body. The buoyancy of the flotation body is selected such the set of at least one depth control element controls the depth of the tail device. The tail device includes at least one inline module, connectable via a fixed link to the tail of the streamer, and a frame element, to which is fastened the flotation body via a fixed link and which can freely rotate around the at least one inline module.

Abstract: A seismic survey system for recording seismic data underwater. The system includes first plural buoys configured to descend to a first predetermined depth (H1) in water, at least one buoy having a seismic receiver for recording the seismic data; a first vessel configured to launch the first plural buoys; and a first acoustic system attached to the first vessel and configured to detect a position of the at least one buoy while underwater. The at least one buoy is instructed to maintain the first predetermined depth (H1) underwater while recording the seismic data.

Abstract: A steerable seismic energy source includes at least one float. The floatation device includes a device for changing buoyancy thereof. A frame is coupled to the at least one float. At least one seismic energy source is suspended from the frame. At least one steering device is coupled to the floatation device or the frame. The at least one steering device includes at least one control surface and a control surface actuator coupled to the control surface. The actuator is configured to rotate the control surface to generate hydrodynamic lift at least in a vertical direction.

Abstract: A buoy for recording seismic signals while underwater. The buoy includes a body; a buoyancy system configured to control a buoyancy of the body to descend to a predetermined depth (H1); a propulsion system configured to actively adjust a position of the body at a given position (X, Y); a seismic sensor located on the body and configured to record the seismic signals; and a control device configured to control the buoyancy system to maintain the body substantially at the predetermined depth (H1) and to control the propulsion system to maintain the body substantially at the given position (X, Y) while the buoy records seismic data, and also to instruct the seismic sensor when to record seismic signals.

Abstract: Depth triggers for marine geophysical survey cable retriever systems. At least some of the illustrative embodiments include causing a submerged geophysical survey cable to surface. In some cases, the causing the cable to surface may include: fracturing a frangible link wherein the frangible link, before the fracturing, affixes position of a piston within a cylinder bore of a housing coupled to the geophysical survey cable, and the fracturing of the frangible link responsive to pressure exerted on a face of the piston as the geophysical survey cable reaches or exceeds a predetermined depth; moving the piston within the cylinder bore; and deploying a mechanism that makes the geophysical survey cable more positively buoyant.

Abstract: A paravane for a seismic acquisition system includes a float, a frame suspended from the float, deflectors affixed to the frame, and means for coupling a tow rope to a lead-in functionally extending between a forward end and an aft end of the frame. The paravane includes means for selectively changing an effective position along the lead-in of the means for coupling the tow cable.

Abstract: A seismic streamer incorporates apparatus for controlling its depth of immersion for modifying and maintaining its degree of immersion, wherein, the streamer being designed for stationary use and including a power supply network, the immersion control apparatus comprises a plurality of variable buoyancy ballasts connected to the power supply network of the streamer and installed at regular intervals along the seismic streamer and each associated with a microcontroller for at least controlling buoyancy of the corresponding ballast, a plurality of pressure sensors also installed at regular intervals along the streamer, at least one receiver for one or more desired value instructions, a bus for distributing the one or more desired value instructions to the ballasts, the microcontroller associated with a given ballasts being adapted to receive at least signals originating from at least one pressure sensor located in the proximity of the ballast and instruction signals originating from the receiver for instruction

Abstract: A paravane for a seismic acquisition system includes a float, a frame suspended from the float, deflectors affixed to the frame, and means for coupling a tow rope to a lead-in functionally extending between a forward end and an aft end of the frame. The paravane includes means for selectively changing an effective position along the lead-in of the means for coupling the tow cable.

Abstract: A seabed resource exploration system includes: a vibrator 1 for transmitting a sound wave into the sea and receiving a scattered wave in which the sound wave is reflected on a boundary surface between seawater and a mixture of methane gas and methane hydrate, which exists in the seawater; and an analyzer 17 for determining that the methane hydrate exists in a seabed immediately under the mixture when backscattering strength, calculated by the transmitted sound wave and the received scattered wave, is in a predetermined relationship. The predetermined relationship satisfies a relationship that a maximum value of the backscattering strength is ?60 to ?30 dB and an average value of the backscattering strength is ?70 to ?50 dB. The backscattering strength is on a grid obtained by cutting the mixture into round slices in the depth direction by a predetermined width, in a range from the seabed to a predetermined height.

Abstract: Method for predicting lithology and porosity of subsurface rocks from seismic reflection data. The seismic data is inverted to yield elastic properties of the rocks such as the compressional and shear impedances. A rock physics model is built to relate porosity, the shale volume fraction, the fluid content of the rock and the elastic properties of the rock. The model is run backward in a second inversion process to solve for porosity and lithologic properties such as the shale volume fraction.

Abstract: A marine seismic streamer steering device comprises at least two hinged sections pivotally coupled to each other and connected between two adjacent sections of the seismic streamer, and a bend control unit that controls bending of the hinged sections relative to the longitudinal axis of the seismic streamer. The steering device further comprises a roll sensor which determines rotational orientation of the body and transmits the orientation to the bend control unit, a lateral position sensor which determines lateral position of the body and transmits the lateral position to the bend control unit, and a depth sensor which determines depth of the body and transmits the depth to the bend control unit. The bend control unit then controls the bending of the hinged sections based on the transmitted rotational orientation, lateral position, and depth of the body.

Abstract: An inner race for a streamer cable connector. The inner race includes first and second curved sections with a screwless fastener for clamping the two sections together about the streamer cable. The two curved sections may be hinged at first ends so that the inner race can be opened like a clam shell for placement about the cable. Cooperating teeth on the second ends of the inner race provide a screwless fastener for the two halves, with the teeth cooperatively arranged to ratchet by each other as the curved sections are closed around the cable.

Abstract: A system for underwater seismic prospecting or exploration on seafloors, especially deep seafloors, including streamers designed to contain the measurement devices and to lie on the seafloor, in the form of an inner tube that is non-stretching and non-compressible and an outer tube that is extensible to a certain extent. Through the injection of liquid between these two tubes, the buoyancy of each streamers is made positive. This enables it to be detached from the seafloor and towed to the next measuring position.

Abstract: A method and device for generating a high amplitude sound wave is provided. The device includes a housing having an open end. A piston is slidably disposed in the open end of the housing and forms a chamber for holding a pressurized liquid. The pressurized liquid acts on the piston to move the piston relative to the housing. A latch is operable to fix the piston relative to the housing and to release the piston. Upon release of the latch, the piston moves relative to the housing to generate the sound wave. In the method of the present invention, a piston is fixed relative to a housing to form a chamber between the housing and the piston. The chamber is filled with a pressurized fluid and the piston is released to allow the pressurized fluid move the piston relative to the housing and generate the sound wave.

Abstract: The present invention discloses a marine seismic system with a control system and at least one powered (manned or unmanned) tow vehicle with at least one seismic apparatus or system attached thereto, the at least one powered tow vehicle for selectively towing under its own power the at least one seismic apparatus or system. In one aspect such towing is done in controlled conjunction with movement of one or more host vessels. In another aspect such a marine seismic system includes at least one service boat for servicing the at least one powered tow vehicle.

Abstract: Device for the adjustment of buoyancy of a seismic cable comprising a main part (1) adapted to firm, integrated mounting into a chosen point in the length of the cable, the main part (1) comprising fastening means (3,4) for one or more weight or buoyancy elements (2) and one or more exchangeable weight or buoyancy elements (2) adapted to being mounted into the main part (1).

Abstract: An over power supply voltage cut-off circuit includes: a power supply voltage supplying path switching part for switching a supplying path of the power supply voltage provided to the power consumption type of load from the power supply voltage generating part in accordance with a driving control signal; a voltage sensing part for sensing an abnormal voltage, in case where a level of the power supply voltage generated from the power supply voltage generating part is over a predetermined set voltage level; and a control signal converting part for converting the driving control signal supplied to the power supply voltage supplying path switching part from the voltage sensing part into a transmission cut-off control signal in accordance with a sensing signal outputted from the voltage sensing part.

Abstract: A seismic cable segment is provided having a longitudinal seam for access into the seismic cable, a cable skin lock, a flotation tube for varying the buoyancy of the seismic cable, external stress members isolated from the inside of the seismic cable, and an environmentally safe gel filling the seismic cable.

Abstract: A marine seismic streamer cable retriever is activated promptly when the cable and its attached retriever exceed a pre-selected safe depth. In an alternative scenario, an electronics module in the cable retriever monitors the presence of through-cable communications traffic between a mother ship and the various sensors in the cable. If an interruption in communications traffic is detected, a clock starts a count-down and sends a warning to the operator aboard ship. At the end of a count-down period, absent prior operator intervention, the cable retriever is activated.

Abstract: A buoyancy control system is disclosed for maintaining a buoyant vehicle at a controlled depth by jettisoning either a heavy liquid or a light liquid. The control system monitors the depth of the buoyant vehicle and determines the direction and magnitude of vertical velocity. If it exceeds the threshold velocity the system calculates how much fluid to jettison in order to decelerate the vehicle to a target velocity. The positive and negative threshold velocities are programmed for control of the average vertical velocity and for depth maintenance. First and second bladders contain heavy and light liquids, respectively. The bladders are subjected to ambient water pressure and are spring loaded and each is provided with an discharge valve. A pressure sensor monitors the vehicle depth and generates a depth signal. A computer derives a velocity signal from the depth signal and calculates the quantity of liquid which should be jettisoned.

Abstract: For the balancing of seismic streamer cables (1) circular ring or sleeve-shaped weighted bodies are adjustably attached at desired intervals on the cable. The weighted bodies can be resilient for temporarily enlarging an opening (3) to receive the cable therethrough and for closing onto the cable in use, or can be circular cross-sectional bodies formed by two parts (4, 5, 4', 5') partially connected together by a single pin (6, 6') and fastened together by a spring pin (7) or hook-shaped pivoted lever (8) engageable with a retainer pin (10).

Abstract: The invention provides a floatation apparatus for maintaining a longitudinal object at a constant depth below the water surface in a body of water. Several airtight chambers are connected in a serial connection to form a string of air tight chambers. A one-way check valve is installed in the chamber at one end of the string while the other end chamber is connected to a nose piece. Air is continuously supplied to the check valve connected to the end chamber. A separate one-way check valve is installed between each pair of adjacent chambers in the string in a manner that air can pass between only in the direction from the air source to the nose member. The floatation apparatus is pivotaly connected to the longitudinal object at more than one place by means of parallel links.

Abstract: A method for reducing signal degradation in a foam covered hydrophone used in seismic marine streamers. Said method comprises purging the foam streamer body with a fluid which is at least partially miscible with an oil used to fill said foam body. Thereafter, said foam body is filled with oil by gravity-assistance. Said method substantially removes air trapped in said foam body thereby reducing said signal degradation. Fluids, which can be utilized include butane, carbon dioxide, and fluorocarbons.

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 marine cable system including one or more elongated cable sections whose buoyancy may be independently controlled. Each section is associated with a pump and a variable volume, elongated bladder. In one embodiment, one reservoir containing buoyant fluid is included, and fluid from the reservoir is pumped between adjacent sections to inflate or deflate the associated bladders. In another embodiment, a rigid reservoir containing compressed gas is included in each section. The associated pump releases gas from the reservoir to inflate the bladder, or pumps gas from the bladder into the reservoir when desired. The pumps are operated in response to control signals from a remote control unit, such as one aboard a vessel towing the cable. One or more depth sensors may be attached in or near each section. Depth information from the sensors may be supplied to the control unit for use in generating the pump control signals. The buoyant fluid is entirely contained within the cable.

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 apparatus to remotely control the depth in the water of a marine cable, such as a streamer of seismic geophones or hydrophones towed behind an exploration boat during seismic surveys of submerged formations, and maintain the cable at a desired depth. The depth at which the cable is maintained may be remotely adjusted for a range of selected depths. A new and improved attaching mechanism for attaching the depth control apparatus to the cable is provided.