Abstract: In a method for synchronizing acoustic asynchronous serial signals while drilling, communication and high-voltage signal isolation between a transmitting terminal and a receiving master control board are realized in an asynchronous serial communication way. The receiving master control board serving as a master control terminal configures parameters for the transmitting terminal in the asynchronous serial communication way and controls the excitation of a sound source. The transmitting terminal is a synchronous sound source excitation signal initiator; signal synchronization is realized under an asynchronous communication condition due to the coordination of the transmitting terminal and the receiving master control board; the transmitting terminal includes a plurality of transmitting boards, and asynchronous serial communication between each of the transmitting boards and the receiving master control board is realized through two data lines R+ and R.

Abstract: Marine seismic surveys, including ocean bottom surveys, utilizing marine vibrator arrays that are capable of being driven in anti-phase to produce a directional source gradient. Marine seismic surveys may include activating the vibrator array to emit a plurality of radiation patterns with at least a first radiation pattern that has a first notch at a take-off angle that is not close to vertical. Some marine seismic surveys includes emitting directive wavefields from two or more simultaneous seismic source arrays, where the two or more seismic source arrays have a phase that changes from shot-to-shot to allow simultaneous source separation of the directive wavefields.

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: An acoustic tool, system, and method for performing down-hole measurements. An encoded pulse sequence is transmitted from an acoustic tool. First reflections are received from the encoded pulse sequences. The first reflections from the encoded pulse sequence are identified from a number of reflections of the encoded pulse sequence. Measurements are performed utilizing the first reflections of the encoded pulse sequence. Other systems and methods are presented.

Abstract: Provided is a method of first arrival picking of multi-channel seismic survey data considering sound source-receiver array that can increase the reliability of a first arrival selected from land seismic survey data or marine seismic survey data that includes background noise. Further, provided is a method of first arrival picking of multi-channel seismic survey data considering source-receiver array, which can improve the reliability of a first arrival or a micro earthquake occurrence location selected from measurement data of a micro earthquake seismic survey.

Abstract: Methods and systems are provided for determining cement quality in an outer annulus of a multi-string cased wellbore having an inner annulus of mud. Data from a sonic logging tool is processed to obtain a slowness dispersion. The slowness dispersion is compared to a plurality of model slowness dispersions generated for a plurality of different values for cement quality in the outer annulus. The cement quality in the outer annulus is determined based on the comparison.

Abstract: A system for detecting objects using ultrasonic waves and methods for making and using the same are provided. The object detection system uniquely encodes each of a plurality of ultrasonic waves and transmit each of the uniquely-encoded ultrasonic waves in a respective direction. The object detection system then receives any of the emitted uniquely-encoded ultrasonic waves that are reflected from an object. By decoding the reflected ultrasonic waves, the object detection system distinguishes among the uniquely-encoded ultrasonic waves and detect the existence and location of the object.

Abstract: Apparatus and methods for identifying drilling cuttings downhole by extracting an echo from a pulse-echo waveform acquired utilizing a downhole ultrasonic tool having an acoustic device. An energy before echo profile preceding the extracted echo is determined, and then the energy before echo profile is processed to remove effects associated with the acoustic device. A cutting is then identified from the processed energy before echo profile.

Abstract: A low frequency underwater sound source for use in an autonomous underwater vehicle includes a cylindrical body having a front portion, a rear portion, a cylindrical piezo-ceramic ring transducer disposed therebetween, and a resonant pipe surrounding the transducer. A gap is formed between an inner surface of the pipe and an outer surface of the transducer. Alternatively, the sound source includes a cylindrical body, a front fairing disposed forward of the cylindrical body, a plurality of metal rods connecting the front of the cylindrical body and the rear of the fairing, a spherical piezo-ceramic transducer disposed between the cylindrical body and the fairing, and a resonant pipe mounted at the front end of the cylindrical body. The spherical transducer is disposed within a cavity within the resonant pipe. A cylindrical orifice is formed between the front end of the resonant pipe and the rear of the fairing.

Abstract: A system that handles direction of arrival (DOA) estimation for acoustic signals using sub-array selection, identifies a plurality of microphone sub-arrays from the plurality of microphones in the microphone-array, selects a set of microphone sub-arrays from the plurality of microphone sub-arrays, and computes a relative time-delay for arrival of the acoustic signals between each pair of microphones of the selected set of microphone sub-arrays. The selection is based on a maximum distance between each pair of microphones of the identified plurality of microphone sub-arrays of the microphone-array. A first microphone sub-array is determined from the selected set of microphone sub-arrays and the DOA of the acoustic signals is estimated with reference to the determined first microphone sub-array. The estimation of the direction of arrival of the acoustic signals is based on the computed relative time-delay for the determined first microphone sub-array of the microphone-array.

Abstract: A housing can be wearable by a user. At least one microphone in or on the housing can sense ambient audio and produce at least one time-domain audio signal. The housing can be passive, such that the sensed ambient audio does not include any sound emitted from the housing. A transformation circuit can transform the at least one time-domain audio signal to form at least one frequency-domain audio signal. An identification circuit can identify a spectral feature in the at least one frequency-domain audio signal. A tracking circuit can track a time evolution of the spectral feature. A determination circuit can determine from the tracked time evolution of the spectral feature that the spectral feature corresponds to an object moving toward the housing. An alert circuit can alert the user, in response to the determination circuit determining that the object is moving toward the housing.

Abstract: The invention notably relates to a method for controlling depth of a seismic cable having ballasts spaced apart along its length and providing a neutral buoyancy to the seismic cable, the seismic cable being adapted for midwater data acquisition, each end of the seismic cable being connected to a respective surface autonomous vessel exerting tension on the cable through a respective lead-in cable having a negative buoyancy, the method comprising, with respect to a target depth, varying the deployed length of each lead-in cable and/or the tension exerted on the cable by each respective surface autonomous vessel. This provides an improved solution for seismic prospecting in aquatic mediums.

Abstract: A downhole acoustic tool and method of use are provided. The acoustic tool includes an acoustic tool body. In addition, a transmitter section located along the acoustic tool body, including four or more transmitters to be driven so as to excite multi-mode waveforms. The acoustic tool further includes an array receiver section located along the acoustic tool body, containing a receiver sub-section comprising four or more receivers axially aligned with the four or more transmitters and spaced axially apart from the transmitter section. The acoustic tool also includes a processor configured to drive the transmitter section to excite multi-mode waveforms and to extract the multi-mode waveforms detected by the receiver section for interpretation of formation properties. A method for measuring a formation using the described acoustic tool is also provided.

Abstract: A method and device of identifying a fracture are provided in the embodiments of the present application. The method comprises: determining three components of structure quantification for each data point in a seismic data volume; constructing a structure quantification matrix of the data point according to the three components of structure quantification for each of the data points; determining feature value and feature vector of the structure quantification matrix of each of the data points; determining fracture attribute value of the data point according to the feature value and feature vector of the structure quantification matrix of each of the data points; constructing a data volume of the fracture attribute according to the fracture attribute values of respective data points; and performing a fracture extraction for the data volume of the fracture attribute according to the feature vectors of the structure quantification matrix of the respective data points.

Abstract: Received shot gathers are sorted to a common receiver gather. A target three-dimensional (3D) amplitude spectrum of seismic wavefield direct arrivals is computed from synthetic data. A 3D amplitude spectrum of seismic wavefield direct arrivals in field data is computed for each receiver. A matched filter is calculated from the 3D amplitude spectrum of field data to target response and applied to downgoing seismic wavefields separated from the common receiver gather to generate filtered downgoing seismic wavefields. Time-dependent smoothing of the filtered downgoing seismic wavefields is performed to generate smoothed downgoing seismic wavefields. A cross-correlation is calculated between upgoing seismic wavefields separated from the common receiver gather and the smoothed downgoing seismic wavefields.

Abstract: Signal measurement units each measure a signal output from a sound source, as a measured signal. Reference signal acquisition units each acquire a reference signal. A weighting processing unit creates weighted reference signals by weighting the reference signals. A time synchronization correction calculation unit calculates a time synchronization correction value based on the weighted reference signals. The time synchronization correction value is a correction value for synchronizing the two measured signals. An arrival time difference calculation unit calculates an arrival time difference based on the time synchronization correction value. The arrival time difference is a difference between elapsed times for the two measured signals acquired by respective ones of the pair of signal measurement units to arrive at the respective ones of the pair of signal measurement units. A sound source position calculation unit calculates a position of the sound source based on the arrival time difference.

Abstract: A method of detecting objects includes transmitting toward an object a first acoustic signal including a first set of pulses including a first number of pulses, and checking if a first echo signal resulting from reflection of the first acoustic signal is received with an intensity reaching an echo detection threshold. If the intensity of the first echo signal reaches the echo detection threshold, the distance to the object is calculated as a function of the time delay of the first echo signal. If the intensity of the first echo signal fails to reach the echo detection threshold, one or more further acoustic signals are transmitted including a set of pulses wherein the number of pulses is increased with respect to the number of pulses in said first acoustic signal.

Abstract: A measuring device that includes in various embodiments a self supporting object attacher and an electronic measuring system supported by the self supporting object attacher. The electronic measuring system is configured to determine or enable the determination of a distance of a space between a first object on which the object attacher is positioned and a second object spaced apart from the first object.

Abstract: Computer systems and methods are provided for time domain reconstructed seismic wavefield imaging. The original source signal or extended source can be forward propagated based on a model of a subsurface region, in order to generate a residual by comparison to field data. The residual can be back-propagated to generate a reconstructed source signal, which can be forward propagated to generate a reconstructed source wavefield. Seismic images can be generated by cross correlating the forward-propagated reconstructed source wavefield and the back-propagated receiver wavefield. The model can include seismic parameters such as velocity, density, anisotropy and attenuation characterizing the subsurface region, and can be iteratively refined to improve image quality, based on the reconstructed source wavefield in comparison to the field data.

Abstract: In accordance with some embodiments of the present disclosure, a method for vibration control for a wellbore logging tool is disclosed. The method may include measuring an initial output signal of the wellbore logging tool. Additionally, the method may include generating a first braking signal based on the initial output signal of the wellbore logging tool. The method may further include transmitting the first braking signal to the wellbore logging tool. The first braking signal may be designed to dampen the vibration of the wellbore logging tool.