Abstract:
A coaxial transducer that uses lead zirconate titanate ceramic or other suitable material as an isolator between the conductors in a coaxial cable to transmit acoustic power at useful levels. The lead zirconate titanate ceramic is diced into thin disks and placed in between spacers made of much stronger insulating material. The coaxial cable is then integrated into a conventional double-armored steel tow cable with a typical diameter of 1″. This provides substantial longitudinal strength and provides crushing resistance to the lead zirconate titanate ceramic when the cable is being deployed or retrieved over a sheave under tension.
Abstract:
System and method for providing an anti-fouling function to a streamer to be towed under water for seismic survey data collection. The method includes mixing a thermoplastic material with a biocide material to form an external sheath material; and forming an external sheath over a main sheath of the streamer to provide the anti-fouling function. The external sheath is formed from the external sheath material such that the biocide material is distributed throughout the external sheath.
Abstract:
Sensors used in mapping strata beneath a marine body are described, such as in a towed array. A first acoustic sensor uses a piezoelectric sensor mounted with a thin film separation layer of flexible microspheres on a rigid substrate. Additional non-acoustic sensors are optionally mounted on the rigid substrate for generation of output used to reduce noise observed by the acoustic sensors. A second sensor is a motion sensor including a conductive liquid in a chamber between a rigid tube and a piezoelectric motion film circumferentially wrapped about the tube. Combinations of acoustic, non-acoustic, and motion sensors co-located in rigid streamer housing sections are provided, which reduce noise associated with different sensor locations.
Abstract:
An apparatus includes a streamer cable section and a unit. The streamer cable section includes an associated group of seismic sensors. The unit connects to an end of the streamer cable section and includes a steering device, a controller, a network repeater and a router. The steering device is controllable to position the streamer section; the controller gathers seismic data provided by the associated group of seismic sensors and introduces the seismic data to a telemetry network of a streamer; the network repeater repeats a signal communicated along the telemetry network; and the router is disposed between the controller and the telemetry network.
Abstract:
A system includes a subterranean survey data acquisition network and a processor. The network has first nodes that are distributed along a length of the network between a first end of the network and a second end of the network. Each of the first nodes is capable of being either in a state in which the first node is transparent to the network or in a state in which the first node is visible to the network. The processor is adapted to communicate with the closest visible first node relative to the first end, and the processor is adapted to, based on the communication, determine whether the closest visible first node is the closest first node of all of the first nodes relative to the first end.
Abstract:
Methods and apparatus for cable termination and sensor integration at a sensor station within an ocean bottom seismic (OBS) cable array are disclosed. The sensor stations include a housing for various sensor components. Additionally, the sensor stations can accommodate an excess length of any data transmission members which may not be cut at the sensor station while enabling connection of one or more cut data transmission members with the sensor components. The sensor stations further manage any strength elements of the cable array.
Abstract:
An apparatus includes a streamer cable having one or more seismic devices disposed within a polymer body and about a core. The polymer body includes a channel defined therein for receiving one or more wires connecting the seismic devices. The wires include slack for withstanding the tensional forces experienced by the streamer cable during deployment and operation. Associated methods are also described.
Abstract:
An ocean bottom cable system includes a sensor cable configured to be extended from a vessel to the bottom of the body of water. The sensor cable includes a plurality of seismic sensor units at spaced apart locations. A lead in cable is coupled at a to at least one of the vessel and a buoy, and to an aft lead in cable segment. The segment includes a cable loop to compensate water-caused motion of the lead in cable substantially without moving the sensor units. A first swivel is disposed between a forward end of the sensor cable and an aft end of the aft lead in cable segment. The first swivel enables relative rotation between the sensor cable and the segment. At least a second swivel is disposed between the second end of the lead in cable and a forward end of the aft lead in segment.
Abstract:
A connection system for connecting external devices to specified locations on a marine seismic streamer. Inner collars having raised bosses are clamped to the cable at specified locations along its length. Each inner collar forms a circular race encircling the cable. An external device is attached to a pair of cuffs in the form of C-shaped cylindrical rings each with a circular inner surface. A gap in the ring interrupts the inner surface. The width of the gap is greater than the diameter of the bosses so that the cuffs may be slid onto the collars when the gaps are aligned with the bosses. The bosses are circumferentially offset when the cable is in its normal operating state to lock the cuff and the external device to the collars. The cuffs and the external device can be installed on or removed from the cable by twisting the cable to align the bosses and sliding the cuffs onto or off of the collars. When installed, the cuffs ride on the races to allow the cable to rotate inside the cuffs.
Abstract:
A marine seismic system having a tow vessel; a first tow member connected to the tow vessel; a second tow member connected to the tow vessel; a first distance member having a first end connected to the first tow member and a second end connected to the second tow member; and a first attachment device connecting the first end to the first tow member, the first attachment member operational between an engaged position securing the first end of the distance member in a fixed position relative to the first tow member and a disengaged position permitting the first attachment device to move along a portion of the first tow member.