Abstract: Methods and apparatus for estimating borehole mud slownesses are disclosed. An example method includes estimating a borehole drilling fluid slowness value based on a tube wave modulus value, a tube-wave slowness value, and a drilling fluid density value. The borehole is associated with an anisotropic elastic medium.

Abstract: The quality of ping-based ultrasound imaging is dependent on the accuracy of information describing the precise acoustic position of transmitting and receiving transducer elements. Improving the quality of transducer element position data can substantially improve the quality of ping-based ultrasound images, particularly those obtained using a multiple aperture ultrasound imaging probe, i.e., a probe with a total aperture greater than any anticipated maximum coherent aperture width. Various systems and methods for calibrating element position data for a probe are described.

Abstract: A beamforming method includes: generating a main beam signal by performing, with a focus on a first region, a delay and sum operation on receiving echo signals; generating a sub beam signal which has a low sensitivity to ultrasound signals reflected off the first region; and generating a narrow beam signal by (i) calculating a coefficient for narrowing an angle of the main beam signal, and (ii) multiplying the main beam signal by the coefficient, wherein in the generating of a sub beam signal, the sub beam signal is generated using a differential signal that is a difference between two beam signals each of which is generated by performing a delay and sum operation on the receiving echo signals, with a focus on a corresponding one of two regions of a subject which are different from the first region and are different from each other.

Abstract: A method for generating acoustic waves under water includes actuating first and second pistons with an actuator system provided inside an enclosure of a source element, to generate a wave having a first frequency, and actuating the first and second pistons with a pressure mechanism attached to the enclosure, to control a pressure of a fluid inside the enclosure such that a pressure of the fluid is substantially equal to an ambient pressure of the enclosure. The enclosure has first and second openings and the first and second pistons are configured to close the first and second openings.

Abstract: Disclosed herein are various embodiments of methods and systems for providing a graphical skeletonization representation of fractures and faults in a subsurface of the earth. According to some embodiments, as fracturing fluid is pumped into a target geologic formation through a well bore, and as the formation fractures or faults in response to the fracturing fluid being pumped under high pressure therein, seismic wavefronts are generated at points of fracture related to movement of a fluid pressure wave induced by fracturing or other fluids moving through the formation, or the extraction of fluids such as gas and/or oil from the formation, which are detected by surface and/or downhole sensors. Data corresponding to signals generated by the surface and/or downhole sensors are recorded and subsequently analyzed to determine in near real-time the locations of the fractures or faults using skeletonization data processing techniques and methods.

Abstract: CMUT devices are used in many applications e.g. for ultrasound imaging and pressure measurement. These devices operate by sensing a change in capacitance caused by deflection of a membrane (32) comprising one of a pair of electrodes in the device by ultrasound exposure of or pressure applied on, the membrane. The CMUT device may be susceptible to the effects of changing temperature.

Abstract: A method and towed sonic array system for defocusing the beampattern of the towed sonic array. The method includes determining an amplitude adjustment and a phase adjustment for each of the sonic projectors; and driving each of the sonic projectors with a drive signal modified by the amplitude adjustment and the phase adjustment for that sonic projector. The amplitude adjustment and phase adjustment for each of the sonic projectors are, at least in part, based upon the distance from that sonic projector to a virtual source. The location of the virtual source may be selected so as to achieve different beampatterns, including wide-sector beams and, in at least one case, a near-omni-directional beampattern. The drive signal may include multiple frequency components, in which case the method may be used to find a set of beamformer coefficients for each of the frequency components and an inverse transform may be used to realize a defocused driving signal.

Abstract: A downscan imaging sonar utilizes a linear transducer element to provide improved images of the sea floor and other objects in the water column beneath a vessel. A transducer array may include a plurality of transducer elements and each one of the plurality of transducer elements may include a substantially rectangular shape configured to produce a sonar beam having a beamwidth in a direction parallel to longitudinal length of the transducer elements that is significantly less than a beamwidth of the sonar beam in a direction perpendicular to the longitudinal length of the transducer elements. The plurality of transducer elements may be positioned such that longitudinal lengths of at least two of the plurality of transducer elements are parallel to each other. The plurality of transducer elements may also include at least a first linear transducer element, a second linear transducer element and a third linear transducer element.

Abstract: A bender bar is presented. The bender bar includes at least two pairs of piezoelectric elements arranged on an inert element to adjust the response frequency of the bender bar. In some embodiments, the piezoelectric elements can be stacked on the inert element. In some embodiments, the piezoelectric elements are symmetrically arranged with respect to the bender bar such that a gap is formed between piezoelectric elements arranged on the inert element.

Abstract: A data transmission device includes a coder configured to code the data into a multifrequency signal. A first array of ultrasonic transducers with a vibrating membrane is disposed on a first surface of a wafer. The first array configured to convert the signal into a multifrequency acoustic signal propagating in the wafer. A second array of ultrasonic transducers is disposed on a second surface of the wafer. The second array includes at least two assemblies of vibrating membrane ultrasonic transducers having resonance frequencies equal to two different frequencies of the multifrequency signal.

Abstract: The application relates to bi-static or multi-static holographic navigation systems, including methods of localizing an emitter or receiver with high precision relative to the sea floor. The system and methods can be used with a fully active sonar or radar system using well synchronized transmitters and receivers. The system and methods can be used with a passive sonar or radar system localizing a transmitter or a receiver based on poorly timed received signals.

Abstract: A method for determining positions and origin times of seismic events occurring in the Earth's subsurface includes accepting as input to the method signals recorded from a plurality of seismic sensors deployed above a subsurface volume of interest. The recorded signals are a representation of seismic amplitude with respect to time. Origin time and location of each of a plurality of subsurface seismic events are determined from the recorded signals. The origin times and locations of each event are inverted to obtain Thomsen's parameters in formations in the volume of interest. Depths of each of the events are determined by individually searching the depth of each event, the inversion with each incorporated new depth including updating the Thomsen parameters and setting as a limit a minimum value of RMS error.

Abstract: An ultrasonic transducer with housing contains a transducer assembly, an outer housing surface being fixed against a barrier surface for transferring ultrasonic waves to and from a barrier. The housing has an inner surface with plateau. A cap closes the housing and the transducer assembly has a piezoelectric transducer with a pressure surface around its outer perimeter and an opposite vibration surface engaging the plateau. A ring engages the pressure surface for biasing the vibration surface against the plateau. A holder engages the cap, transducer and ring for positioning and a plurality of springs are spaced around the transducer perimeter and between the cap and ring for biasing the vibration surface toward or against the raised plateau. A viscous couplant is between the vibration surface and plateau for enhancing transmission of the ultrasonic waves.

Abstract: A technique facilitates obtaining seismic data in a marine environment. An array of acoustic sources is deployed in a marine environment. The array can be utilized for creating acoustic pulses that facilitate the collection of data on subsea structures. The methodology enables optimization of acoustic source array performance to improve the collection of useful data during a seismic survey.

Abstract: A sensor streamer drag body system. At least some of the example embodiments include a system having a sensor streamer towable behind a vessel in a body of water, the sensor streamer defining a defining a distal end and a proximal end, the proximal end nearest the vessel. The system further includes a drag body coupled to the distal end of the sensor streamer, wherein the drag body remains submerged while the sensor streamer is deployed. The drag body includes an inertial navigation system. The inertial navigation system is configured to determine a position of the drag body, the drag body lacking an internal GPS.

Abstract: A measuring method of touch sensitive area size of a SAW sensor module is provided. The SAW sensor module comprises a substrate configured for propagating SAW, a first transmitter and a first receiver corresponding to a first axis, a second transmitter and a second receiver corresponding to a second axis. The SAWs emitted by the first transmitter at least pass through a first initial distance xi, propagate through a second axis length y after reflected by a first SAW reflecting bar, and enter the first receiver after reflected by a second SAW reflecting bar. The SAWs emitted by the second transmitter at least pass through a second initial distance yi, propagate through a first axis length x after reflected by a third SAW reflecting bar, and enter the second receiver after reflected by a fourth SAW reflecting bar.

Abstract: An object detection method using ultrasonic waves includes: emitting a plurality of ultrasonic signals sequentially according to a time interval; sensing a sound wave formed by each of the ultrasonic signals to generate a reflected signal; and analyzing the reflected signal to detect at least one reflection object. It can be clearly known whether a reflection object is appearing, moving and the moving direction by the method.

Abstract: Techniques are disclosed relating to testing of seismic air guns, for example via bubble tests. According to some embodiments of these techniques, a firing sequence for testing the air guns may be determined that reduces the amount of interaction between firings. Further, firing time delays may also be determined in order to further reduce the interactions. Accordingly, a test of an array of air guns may be completed relatively quickly.

Abstract: Aspects of the technology described herein relate to ultrasound device circuitry as may form part of a single substrate ultrasound device having integrated ultrasonic transducers. The ultrasound device circuitry may facilitate the generation of ultrasound waveforms in a manner that is power- and data-efficient.

Abstract: A method for localizing signals of interest includes initializing characteristics of the signals. Signals are acquired from a sensor array having at least three acoustic sensors. After digitization and conditioning, the signals associated with each sensor are validated by comparison with initialized characteristics. The signals are correlated across sensor groups to obtain time differences of arrival (TDOA). These TDOA are validated and associated with other TDOA from different times. TDOA from different sensor pairs are associated when they share a common sensor. A hyperbola of possible locations is created for each validated TDOA. Summation of the hyperbolas gives an intensity function. The location is identified as the most intense point in the intensity function. The source can be tracked across time as a computer output.