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:
An apparatus includes a streamer having one or more sensor holders for retaining seismic sensors therein. The sensor holders have a reduced cross-sectional area to increase gel continuity and coupling through the streamer.
Abstract:
A method and apparatus for a seismic cable is disclosed. In one embodiment, the seismic cable includes a first cable segment and a second cable segment coupled together by a connector that prevents transmission of power and data signals between the first cable segment and the second cable segment. Each cable segment includes an inner jacket defining a hollow core, a braided strength fiber surrounding the inner jacket, and an outer jacket circumferentially surrounding the braided strength fiber, wherein the connector isolates the first and second cable segments.
Abstract:
A seismic streamer system for acquiring seismic data includes a plurality of first cable sections each employing a first sensor configuration therein, and at least one second cable section operatively connected to one or more of the first cable sections and employing a second sensor configuration therein. In various embodiments of the streamer system, one or more of the second cable sections are sparsely integrated into a streamer, a streamer array, and/or a seismic spread. The first sensor configuration may, e.g., include a conventional hydrophone distribution, and the second sensor configuration may, e.g., include multicomponent sensors such as at least one of a particle velocity sensor, a pressure gradient sensor, an accelerometer, and a combination thereof. The present invention is useful for attenuating noise in the measured seismic data as well as deghosting the data. A particular deghosting process includes decomposing the up- and down-going parts of the vertical component of particle velocity associated with the acoustic wave reflections from the strata.
Abstract:
A marine electromagnetic sensor cable system includes a first sensor cable subsystem including at least a first sensor cable segment. The first sensor cable segment includes a plurality of spaced apart electrodes which electrically contact a body of water when the first sensor cable segment is immersed therein, and an electrical conductor coupled to each electrode, each electrical conductor extending from one longitudinal end of the sensor cable segment to the other. The system includes a first signal processing module electrically coupled to a longitudinal end of the first sensor cable segment, and including a voltage measuring circuit electrically connected between two or more electrodes from the first plurality of electrodes. Marine electromagnetic surveys are conducted using the marine electromagnetic sensor cable system.
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).
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 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:
A marine sensor streamer includes a jacket covering an exterior of the streamer. At least one strength member extends the length of the jacket. At least one stiffener element extends inside the length of the jacket. The at least one stiffener element includes a gas filling the interior of a flexible, compressible tube and filler elements disposed in the gas. The filler elements have exterior shape and surface roughness such that upon compression of the gas, the filler elements are urged into contact with each other, causing the streamer to become substantially rigid.
Abstract:
In one example, a detachable cable assembly includes: a flexible cable including a weather resistant jacket and a conductor inside the jacket; a first electrical connector connected to the cable conductor at a first end of the cable and configured to make a detachable electrical connection to a seismic sensing unit; a weather resistant first cover protecting the first end of the cable and the first connector, the first connector exposed through the first cover for connecting to the sensing unit; a second electrical connector connected to the cable conductor at a second end of the cable and configured to make a detachable electrical connection to the control unit; and a weather resistant second cover protecting the second end of the cable and the second connector, the second connector exposed through the second cover for connecting to the control unit.