Abstract: In one aspect, an ultrasound transducer system comprises a two-dimensional array of transducer elements, the transducer elements having a first side comprising individual first electrodes in electrical communication with control circuitry of the ultrasound transducer system. A matching layer is coupled to a second side of the transducer elements via an electrically conductive face, wherein the electrically conductive face serves as a common electrical contact for the transducer elements. The matching layer also comprises kerfs extending to a depth less than the electrically conductive face.

Abstract: An assembly with a first coupling having a forward bulkhead device is provided. The forward bulkhead device contains a first connector insert having first end connections for wires and optical fibers of an acoustic array. The assembly also includes a second coupling having an aft bulkhead device therein. The aft bulkhead device contains a second connector insert having second end connections for the wires and optical fibers of the acoustic array. The forward bulkhead device further includes an alignment assembly. The alignment assembly is matable with the aft bulkhead device to align the first connector insert with the second connector insert. The forward bulkhead device further includes a locking ring connecting the forward bulkhead device with the aft bulkhead device.

Abstract: Various downhole logging tools and methods of using and making the same are disclosed. In one aspect a method evaluating cement bond quality in a well is provided. In a well with a particular casing/tubing configuration, waveforms of acoustic energy returning from the tubing and the casing with the tubing present are recorded. A frequency spectrum from the recorded waveforms is determined. Amplitudes of the returning acoustic energy at one or more preselected frequency(s) of interest of a range of frequencies at which the amplitudes are noticeably affected by cement bond quality for the particular casing/tubing configuration are determined. The determined amplitudes are compared with one or more baseline amplitudes to look for indications of cement bond quality. Other aspects involve time domain analysis.

Abstract: The present invention discloses a device for measuring dynamic evolution of a three-dimensional disturbed stress under mining disturbance, comprising an outer steel cylinder. Three three-direction sensing units are arranged on the outer steel cylinder. Any two of three stress measurement directions of each three-direction sensing unit are perpendicular to each other. Nine stress measurement directions of the three three-direction sensing units are different. The present invention also discloses a method for measuring dynamic evolution of a three-dimensional disturbed stress under mining disturbance. In the present invention, stresses are measured from three perpendicular directions which are inclined, so the difficulty in measuring a three-dimensional stress in a borehole is overcome; and a spatial stress value is measured by three three-direction sensing units, and thus the size and direction of a disturbed principal stress in the borehole are calculated.

Abstract: A system for estimating a property of a region of interest includes an acoustic measurement device including a transmitter configured to emit an acoustic signal having at least one selected frequency configured to penetrate a surface of a borehole in an earth formation and produce internal diffuse backscatter from earth formation material behind the surface and within the region of interest, and a receiver configured to detect return signals from the region of interest and generate return signal data. The system also includes a processing device configured to receive the return signal data, process the return signal data to identify internal diffuse backscatter data indicative of the internal diffuse backscatter, calculate one or more characteristics of the internal diffuse backscatter, and estimate a property of the region of interest based on the one or more characteristics of the internal diffuse backscatter.

Abstract: Disclosed herein is a sonobuoy cartridge percussion apparatus. A sonobuoy cartridge percussion apparatus according to an aspect of the present invention includes: a CO2 cartridge filled with CO2 gas; a percussion ram configured to hit one end of the CO2 cartridge; a spring configured to enable the percussion ram to hit the CO2 cartridge by applying force to the percussion ram; a CO2 cartridge fastening body configured such that a spring reception hole is formed therein to enable the spring to be compressed and inserted into the spring reception hole; and a thread-shaped fastening member configured such that one end thereof is wound around the percussion ram and the other end thereof is passed through the spring reception hole, wherein the fastening member compresses the spring, and is fastened to a stop protrusion formed on the CO2 cartridge fastening body.

Abstract: A method of correcting clock drift in at least one slave clock in a seismic node. The method comprises obtaining a number of clock drift measurements of the at least one slave clock in the at least one seismic node. A clock drift correction function as a function of time is calculated by curve fitting the number of clock drift measurements to a 2nd order polynomial. A time of reference of the recorded seismic sensor data is corrected by the 2nd order polynomial clock drift correction function.

Abstract: A downhole tool having an acoustic transducer for downhole measurements. A backing is in contact with an inner surface of the transducer. A first structure is coupled to a first housing. A second structure is coupled to a second housing. A member includes first, second, and third portions. The first portion is coupled to the first structure. The second portion is coupled to the second structure. At least one of the first and second structures is coupled to the member and has a degree of freedom relative to the member. The third portion extends longitudinally through the backing between the first and second portions such that compressional forces on the first and second housings are transferred through the first and second structures and the backing. A canister contacts an outer surface of the transducer and exerts radial forces on the transducer when exposed to pressures higher than atmospheric pressure.

Abstract: The object of this invention is to provide an ultrasonic transducer for a measuring device capable of widening a frequency band suitable for transmitting and receiving ultrasonic waves while reducing the manufacturing cost. The ultrasonic transducer for a measuring device includes a substantially disc-shaped base material that serves too as an acoustic-matching layer and substantially disc-shaped piezoelectric element that is joined to the base material. The piezoelectric element is formed with grooves extending in the planar direction so that they do not cross one another, and the plurality of strip-shaped vibration units are arranged through the grooves. The length of the vibration unit becomes shorter as the distance from the center of the piezoelectric element increases. Then, the piezoelectric element vibrates in the thickness direction in the first-frequency band and vibrates in the radial direction in the second-frequency band, which is lower than the first-frequency band.

Abstract: A seabed object detection system is provided. The system can include a receiver array including streamers. The system can include a plurality of receivers coupled with the streamers. The system can include a receiver array cross-cable to couple with the first streamer and to couple with the second streamer. The receiver array cross-cable can be disposed at a first depth of a body of water. The system can include a first diverter and a second diverter coupled with the receiver array cross-cable. The system can include a source array including a first source and a second source. The source array can be coplanar to the receiver array. The system can include a source array cross-cable to couple with the first source and to couple with the second source, the source array cross-cable disposed at a second depth of the body of water.

Abstract: Seismic data are obtained by recording simultaneously in seismic streamer, acquired by activating approximately simultaneously two or more seismic sources towed at two positions in the vicinity of seismic streamers. A residual is updated iteratively for an inversion solution for the activations of the two or more seismic sources. The iterative updating of the residuals utilizes a sequence of overlapping temporal windows containing reflection events and utilizes normal moveout corrections based on largest reflection events in each temporal window. A final updated residual is added to a final updated model result.

Abstract: The disclosure discloses a trajectory optimization method and device for accurately deploying marine sensors under water. The method includes the following steps. 1. Randomly select N sets of initial control variables within a range. 2. Input all of N sets of xi to the sensor's underwater glide kinematics and dynamics models, and calculate the smallest distance between N actual deployment positions and target deployment positions. 3. Determine whether the number of iterative operations is less than the preset value, if yes, perform global random walk and local random walk on N sets of xi, obtain N sets of xi again, and return to step 2; otherwise, go to step 4. 4. Output the control variable xi corresponding to ?s(x)nminmin and the corresponding trajectory as the optimal control variable and optimal trajectory. The disclosure can improve the accuracy of prediction on the underwater three-dimensional trajectory of the marine sensor.

Abstract: A packing module includes a volumetrically efficient structure for separately retaining sensors and a cable of a sensor array. The packing module includes a tray that supports the sensors and a retaining leaf arrangement that extends outwardly from the tray to retain the cable on the tray. The retaining leaf arrangement includes a plurality of nested leaves that are spaced relative to each other. Packing the module includes placing the sensors separately and in succession on the tray and inserting a portion of the cable in the retaining leaf arrangement in between each placing of a sensor. The placement of a sensor and insertion of a portion of the cable occurs alternately until the entire sensor array is accommodated. Deployment of the sensor array may occur by alternately removing a sensor and a portion of the cable until the sensor array is displaced from the module.

Abstract: An ultra-wide bandwidth acoustic transducer may include multiple layers, including an inner piezoelectric layer, a polymer coupling layer and an outer piezoelectric layer. The polymer layer may be located between, and may be bonded to, the inner and outer piezoelectric layers. The transducer may have multiple eigenfrequencies of vibration. These eigenfrequencies may include primary resonant frequencies of the inner and outer piezoelectric layers respectively and may also include resonant frequencies that arise due to coupling between the layers. An acoustic backscatter system may employ such a transducer in backscatter nodes as well as in a transmitter. The multiple eigenfrequencies may enable the system to perform spread-spectrum communication at a high throughput. These multiple eigenfrequencies may also enable each backscatter node to shift frequency of an uplink signal, which in turn may enable the system to mitigate self-interference and to decode concurrent signals from multiple backscatter nodes.

Abstract: A sonar survey system including a multibeam echo sounder using plural transmit projectors and plural receive hydrophones, wherein beams with associated magnitudes are received such that the largest magnitude beam(s) are identified as characterizing beam(s) and data associated with these characterizing beam(s) is used as a compressed characterization of the ensonified space.

Abstract: Disclosed are apparatuses, systems, and methods for urging matching rotational orientations of geophysical sensors in a marine geophysical streamer. An embodiment discloses a marine geophysical streamer comprising a jacket; spacers disposed longitudinally within the jacket, the spacers containing geophysical sensors; and an alignment preserver disposed within the jacket, the alignment preserver encompassing at least a portion of each of the spacers and configured to urge matching rotational orientations for the geophysical sensors.

Abstract: The present disclosure is directed to a system to locate seismic data acquisition units in a marine environment. The system can include a first seismic data acquisition unit. The first seismic data acquisition unit can include a case having a wall defining an internal compartment, a power source, a clock, a seismic data recorder, and at least one geophone disposed within the case. The system can include a flexible connector and a telltale component, wherein the flexible connector and the telltale component can be stored adjacent to the first seismic data acquisition unit, wherein a second seismic data acquisition unit is coupled with the first seismic data acquisition unit.

Abstract: An acoustic logging tool may comprise a center load carrying pipe, a receiver module connected to the center load carrying pipe, one or more transmitter modules connected to the center load carrying pipe, and one or more mass modules connected to the center load carrying pipe.

Abstract: A system to perform marine surveying may include a pair of identical design autonomous marine survey vehicles configured for coordinated operations. The vehicles may navigate and transit from a launch location to a geographically distant designated survey location, continuously survey and transit to a designated recovery location. A pair of vehicles may operate interchangeably at the sea surface, semi-submerged and underwater. Each may generate energy when operating at the surface and store energy in a rechargeable battery to power vehicle operation. The payload may include a sensor system to acquire seabed sensor data. A data storage system may store the sensor data. An on-board payload quality control system may analyze data validity. Positioning when the vehicle is collecting seabed sensor data may be determined with high precision, to provide survey data of high precision.

Abstract: Aspects of the present disclosure include methods for communication using a MIMO channel, such as an acoustic channel for underwater communication. An acoustic receiver may receive a signal comprising information encoded in at least one transmitted symbol. Using a two-layer iterative process, the at least one transmitted symbol is estimated. The first layer of the two-layer process uses iterative exchanges of soft-decisions between an adaptive turbo equalizer and a MAP decoder. The second layer of the two-layer process uses a data-reuse procedure that adapts an equalizer vector of both a feedforward filter and a serial interference cancellation filter of the adaptive turbo equalizer using a posteriori soft decisions of the at least one transmitted symbol. After a plurality of iterations, a hard decision of the bits encoded on the at least one transmitted symbol is output from the MAP decoder.