Abstract: Sensors used in mapping strata beneath a marine body are described, such as used in a flexible towed array. A first 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. A second sensor is a traditional acoustic sensor or a novel acoustic sensor using 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. Combinations of acoustic, non-acoustic, and motion sensors co-located in rigid streamer housing sections are provided.

Abstract: Streamers used in mapping strata beneath a marine body are described, such as in a flexible neutrally buoyant towed array. A connector is used to longitudinally join a first and second streamer section and/or to connect a streamer section to a streamer stabilizer. The connector contains at least one of: (1) means for distributing axial stress over a larger volume or along a longer x-axis length of the streamer relative to the absence of the means for distributing; (2) forming an increasing radius of curvature along the length of the connector as a function of distance from the first leading streamer cable section; and (3) co-moving an inner stress bearing element and an outer wall of the connector preventing intermediate streamer elements, such as a wire bundle from picking up noise related to the movement stress.

Abstract: Sensors used in mapping strata beneath a marine body are described, such as used in a flexible towed array. A first 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. A second sensor is a traditional acoustic sensor or a novel acoustic sensor using 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. Combinations of acoustic, non-acoustic, and motion sensors co-located in rigid streamer housing sections are provided.

Abstract: Sensors used in mapping strata beneath a marine body are described, such as in a flexible neutrally buoyant towed array. A first 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. The liquid transfer signal from a gravitational bottom of the sensor while rejecting water body surface reflected noise. A second sensor is a traditional acoustic sensor or a novel acoustic sensor using a piezoelectric sensor mounted with a thin film separation layer of flexible microspheres on a rigid substrate. Combinations of motion sensors and acoustic sensors co-located in a rigid streamer housing sections are provided.

Abstract: Sensors used in mapping strata beneath a marine body are described, such as used in a flexible towed array. A first 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. A second sensor is a traditional acoustic sensor or a novel acoustic sensor using 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. Combinations of acoustic, non-acoustic, and motion sensors co-located in rigid streamer housing sections are provided.

Abstract: Streamers used in mapping strata beneath a marine body are described, such as in a flexible neutrally buoyant towed array. A streamer cable is described using polyurea, within a sleeve, where the polyurea demonstrates durability in the presence of extreme hydrodynamic forces at depths in the marine body. The sleeve optionally uses longitudinal directed, inward pointing ribs to distribute forces and to minimize expansion of micro-cracks. The polyurea is optionally made neutrally buoyant through the controlled dosage of hollow, flexible, and/or glass microspheres into the polyurea at time of polymerization. A stress relieving connector is optionally used to longitudinally join a first and second streamer section and/or to connect a streamer section to a streamer stabilizer.

Abstract: A surface structure is provided for reducing drag and/or for reducing turbulence on or proximate any element of a streamer cable or towed sensor array. The surface structure comprises a non-uniform surface having ridges, channels, expanding channels, dimples, bumps, backward facing diamonds, a saw tooth pattern, or the like integrated into, adhered to, wrapped, and/or coated onto a surface of the streamer cable. The sharkskin like material, coating, or surface is optionally an array of denticles or a sheet that is also useful for fuel reduction and/or ease of guidance due to lower resistance and noise reduction in towed sensors due to reduction/breakup of localized zones of turbulence.

Abstract: Streamers used in mapping strata beneath a marine body are described, such as in a flexible neutrally buoyant towed array. A connector is used to longitudinally join a first and second streamer section and/or to connect a streamer section to a streamer stabilizer. The connector contains at least one of: (1) means for distributing axial stress over a larger volume or along a longer x-axis length of the streamer relative to the absence of the means for distributing; (2) forming an increasing radius of curvature along the length of the connector as a function of distance from the first leading streamer cable section; and (3) co-moving an inner stress bearing element and an outer wall of the connector preventing intermediate streamer elements, such as a wire bundle from picking up noise related to the movement stress.

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: Sensors used in mapping strata beneath a marine body and/or structures on a marine body floor are described, such as in a flexible buoyancy adjustable towed array. A first sensor is a traditional acoustic sensor or a novel acoustic sensor using 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. 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 and/or localized turbulence.

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: Sensors used in mapping strata beneath a marine body are described, such as used in a flexible towed array. A first 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. A second sensor is a traditional acoustic sensor or a novel acoustic sensor using 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. Combinations of acoustic, non-acoustic, and motion sensors co-located in rigid streamer housing sections are provided.

Abstract: Sensors used in mapping strata beneath a marine body are described, such as in a flexible neutrally buoyant towed array. A first 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. The liquid transfer signal from a gravitational bottom of the sensor while rejecting water body surface reflected noise. A second sensor is a traditional acoustic sensor or a novel acoustic sensor using a piezoelectric sensor mounted with a thin film separation layer of flexible microspheres on a rigid substrate. Combinations of motion sensors and acoustic sensors co-located in a rigid streamer housing sections are provided.

Abstract: An acoustic sensor array may include sensor sections positioned along a length of a strain member. One or more sensors may be disposed within a sensor section. One or more sensors may be encapsulated in a molding material using a reaction injection molding (RIM) process to form a sensor section. Buoyant sections may be formed between sensor sections on the strain member. Buoyant sections may be formed by encapsulating a portion of the strain member in a buoyant molding material using a RIM process. Buoyant sections and/or sensor sections may include hollow microspheres. A concentration of hollow microspheres may be adjusted to control a buoyancy of the array. The strain member, the sensor sections, and the buoyant sections may be joined to form the array.

Abstract: An acoustic sensor may include a base, a diaphragm, and a piezoelectric film. A cup may be disposed around the sensor. A filling material may be injected inside the cup and around the sensor. An end cap may be placed at an end of the cup to enclose the filling material within the cup. The cup may include longitudinal fibers disposed in an adhesive matrix. The acoustic sensor and the cup may be encapsulated in a molding material using a reaction injection molding (RIM) process to form a sensor section. Buoyant sections may be formed between sensor sections on a strain member. Buoyant sections may be formed by encapsulating a portion of the strain member in a buoyant molding material using a RIM process. be The strain member, the sensor sections, and the buoyant sections may be joined to form an array.

Abstract: An acoustic sensor array may include sensor sections positioned along a length of a strain member. One or more sensors may be disposed within a sensor section. One or more sensors may be encapsulated in a molding material using a reaction injection molding (RIM) process to form a sensor section. Buoyant sections may be formed between sensor sections on the strain member. Buoyant sections may be formed by encapsulating a portion of the strain member in a buoyant molding material using a RIM process. Buoyant sections and/or sensor sections may include hollow microspheres. A concentration of hollow microspheres may be adjusted to control a buoyancy of the array. The strain member, the sensor sections, and the buoyant sections may be joined to form the array.

Abstract: A non-fluid-filled streamer cable or towed array for performing seismic surveys in water-covered areas includes a plurality of serially coupled active cable sections. Each active cable section includes an electromechanical cable that contains a single central strain member. A wire bundle is placed around the central strain member for transporting electrical power and data through the active section and an inner protective jacket is formed around the central strain member and wire bundle. A foam material is extruded around the inner protective jacket to provide a predetermined buoyancy to the fully assembled active cable section and an outer protective jacket is formed around the foam jacket. A potting compound is formed between, and bonds to, the inner protective jacket and outer protective jacket to provide a water block at each hydrophone location.

Abstract: An acoustic sensor having one or more segments are electrically coupled to provide a response corresponding to an acoustic pressure applied to the segments. Each segment contains at least one substrate of a desired shape and at least two active members made from a flexible, resilient piezoelectric material, preferably, a polyvinylidene fluoride material. Each substrate includes an enclosed chamber on an outer surface wherein a first active element is within the chamber and a second active element is sealingly placed on the enclosed chamber. The second active element is preferably bonded to a compliant diaphragm sealed to the substrate to provide the sealed chamber. An output response from the first active member is combined with an output response from the second active member to provide for a combined output response having reduced noise. The second active element is covered with a protective layer of a suitable material, preferably a polymer material.

Abstract: The present invention provides an acoustic sensor having one or more segments that are electrically coupled to provide a response corresponding to a hydrodynamic pressure applied to the segments. Each segment contains a substrate of a desired shape with a concavity on an outer surface that is sealingly enclosed by an active member made from a flexible, resilient piezoelectric material. PVDF material is preferably used as the piezoelectric active element. The active element may be bonded to a compliant diaphragm sealed to the substrate to provide the sealed chamber. The active member is covered with a protective layer of a suitable material, preferably a polyvinyl material. In one embodiment, the diaphragm includes a standoff ledge and is placed on the outer surface of the substrate to define the sealed chamber between the diaphragm and the outer surface of the substrate.

Abstract: The present invention provides a non-fluid-filled streamer cable or towed array for performing seismic surveys in water-covered areas. The streamer cable includes a plurality of serially coupled active cable sections. Each active cable section includes an electro-mechanical cable that contains a single central strain member. A wire bundle is placed around the central strain member for transporting electrical power and data through the active section. A nonconductive foam material is extruded around the central strain section to provide a predetermined buoyancy to the fully assembled active cable section. A number of hydrophones are formed around and outside the electro-mechanical cable. The hydrophone preferably includes a pair of active element connected in series opposition. The hydrophone is centrally located within an outer jacket formed over the hydrophone. Electronic components, such as pre-amplifiers, are placed within the hydrophones.