Abstract: Systems and methods are provided for acquiring seismic data using a wireless network and a number of individual data acquisition modules that are configured to collect seismic data and forward data to a central recording and control system. In one implementation, a number of remote modules (301) are arranged in lines. Base station modules (302) receive information from the lines and relay the information to a central control and recording system (303). Radio links operating on multiple frequencies (F1-F12) are used by the modules (301). For improved data transfer rate, radio links from a remote module (301) leap past the nearest remote module to the next module closer to the base station.

Abstract: A wireless seismic data acquisition unit with a wireless receiver providing access to a common remote time reference shared by a plurality of wireless seismic data acquisition units in a seismic system. The receiver is capable of replicating local version of remote time epoch to which a seismic sensor analog-to-digital converter is synchronized. The receiver is capable of replicating local version of remote common time reference for the purpose of time stamping local node events. The receiver is capable of being placed in a low power, non-operational state over periods of time during which the seismic data acquisition unit continues to record seismic data, thus conserving unit battery power. The system implements a method to correct the local time clock based on intermittent access to the common remote time reference. The method corrects the local time clock via a voltage controlled oscillator to account for environmentally induced timing errors.

Abstract: Systems and methods create velocity models for a single well or for a set of wells. In one implementation, a system optimizes a time-depth relationship applied to data points from a single well to estimate coefficients for a linear-velocity-in-time function that models the data points. The system optimizes by reducing the influence of outlier data points, for example, by weighting each data point to decrease the influence of those far from the velocity function. The system also reduces the influence of top and bottom horizons of geological layers by applying data driven techniques that estimate the velocity function in a way that reduces dependence on the boundary conditions. The systems and methods can also create velocity models based on data from a set of wells, applying a well weights method to reduce the influence of outlier wells and thereby prevent wells with aberrant data from degrading a correct velocity model.

Abstract: The invention relates to a method for acquiring seismic data at a plurality of positions spread out over a zone on the seabed which includes transmitting acoustic waves in the water layer above the zone by a plurality of sources, for each of the acquisition positions, dropping from the surface a seismic acquisition equipment, the equipment comprising a seismic acquisition unit and autonomous guiding equipment adapted to receive while descending acoustic signals from the sources and to control its trajectory according to the received acoustic signals so as to direct said equipment towards said position, performing the seismic acquisition, causing the acquisition equipments to move up to the surface, and retrieving the acquisition equipments on the surface.

Abstract: An ultrasonic imaging method is provided. A wideband acoustic pulse is fired at a wall. A wideband response signal is received. The wideband response signal is processed to select an impedance measurement frequency. A wavelet having a characteristic frequency approximately equal to the impedance measurement frequency is fired. A wavelet response signal is received. A reflection coefficient is determined from the wavelet response signal. An impedance measurement is calculated from the reflection coefficient. Related tools and systems are also disclosed.

Abstract: Systems and methods for automatic steering of marine seismic sources are described. One system comprises a marine seismic spread comprising a towing vessel and a seismic source, the seismic source comprising one or more source arrays each having a center of source array, each source array having one or more source strings; a seismic source deployment sub-system on the towing vessel, the sub-system controlled by a controller including a software module, the software module and the deployment sub-system adapted to control an inline distance between one of the centers of source array and a target coordinate. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, allowing a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: Control mechanisms, computer software and methods for driving vibrational source arrays underwater. An incoherent acquisition scheme drives individual source elements simultaneously and incoherently while a coherent acquisition scheme drives high-frequency individual source elements simultaneously and incoherently and low-frequency individual source elements simultaneously and coherently. Thus, denser coverage and an increased energy input is achieved for the source arrays.

Abstract: An apparatus for imaging an earth formation, the apparatus including: a logging instrument configured to be conveyed through a borehole penetrating the earth formation; a source of acoustic waves disposed at the logging instrument, wherein the source is configured to emit first acoustic waves having at least a first frequency and to enable intermodulation of the first acoustic waves in a medium having a nonlinear acoustic property resulting in generating new acoustic waves that are transmitted to the earth formation, the new acoustic waves having a new frequency different from the at least first frequency; and a receiver of acoustic waves configured to receive the new acoustic waves reflected from the earth formation, wherein the received new acoustic waves provide an image of the earth formation.

Abstract: This is a method of separating simultaneous sources that uses an inversion-type approach. Each source will preferably activated at a random time with respect to the others. These random delays tend to make the interference between sources incoherent while the reflections create coherent events within a series of shots. The shot separation is performed via a numerical inversion process that utilizes the sweeps for each shot, the start times of each shot, and the coherence of reflection events between nearby shots. Implementation of this method will allow seismic surveys to be acquired faster and cheaper.

Abstract: In some aspects of the invention, a method of generating a beam of acoustic energy in a borehole is disclosed. The method includes generating a first acoustic wave at a first frequency; generating a second acoustic wave at a second frequency different than the first frequency, wherein the first acoustic wave and second acoustic wave are generated by at least one transducer carried by a tool located within the borehole; transmitting the first and the second acoustic waves into an acoustically non-linear medium, wherein the composition of the non-linear medium produces a collimated beam by a non-linear mixing of the first and second acoustic waves, wherein the collimated beam has a frequency based upon a difference between the first frequency range and the second frequency, and wherein the non-linear medium has a velocity of sound between 100 m/s and 800 m/s.

Abstract: A sweep generator is employed to generate a sweep to be used by a seismic vibrator device for generating a desired target output spectrum, wherein the frequency sweep is designed so as to comply with one or more constraints imposed by the seismic vibrator device and/or imposed by the environment in which the device is to be used. In one embodiment, a sweep generator determines a sweep for achieving a desired target output spectrum by a given seismic vibrator device in compliance with at least a pump flow constraint imposed by the seismic vibrator device. In another embodiment, a sweep generator determines a sweep for achieving a desired target output spectrum by a given seismic vibrator device in compliance with all of multiple operational constraints of the seismic vibrator device, such as both mass displacement and pump flow constraints. Environmental constraints may also be accounted for in certain embodiments.

Abstract: A marine seismic streamer includes at least one particle motion sensor array. The array includes a plurality of particle motion sensors disposed at spaced apart locations along the streamer. Outputs of the particle motion sensors are functionally coupled to form an array. A number of the particle motion sensors and a spacing between adjacent particle motion sensors are selected to attenuate noise in a selected mode of propagation and within a selected wavenumber range. The streamer includes means for weighting a signal output of each particle motion sensor in the at least one array. A signal weight applied to each sensor by the means for weighting is selected to optimize attenuation of the noise.

Abstract: The invention is a method to predict surface-wave waveforms (306) and subtract them (307) from seismic data. Prediction is done by estimating a set of surface-consistent components (transfer functions in the frequency domain or impulse responses in time domain) that best represent changes in the waveforms for propagation along the surface from source to receiver (303). The prediction uses a mathematical expression, or model, of the earth's filtering effects, both amplitude and phase, as a function of frequency. The desired surface-consistent components are model parameters, and model optimization is used to solve for the surface-consistent components. The surface-consistent components may include filter transfer functions for each source location, each receiver location, and for propagation (302) through each region (301) of the surface that exhibits lateral variation.

Abstract: Seismic acquisition systems are disclosed that allow contemporaneous seismic sources to be separated from a composite signal comprising two or more constituent seismic sources. In some embodiments, a representation of the composite signal may be developed that includes a noise contribution of undesired signals present in the composite signal. Additionally, an operator, referred to herein as an “annihilator”, may be developed such that it may be conditioned and inverted to minimize undesired noise contributions in the composite signal. This inversion may assist in recovering the constituent seismic sources from the composite signal. Furthermore, in some embodiments, the accuracy with which the constituent source measurements are approximated may be increased by implementing them as random sweeps having a conventional length.

Abstract: A system for tracking underwater equipment is disclosed which includes a buoy and an underwater animal trap connected to the buoy. A position sensing unit is mounted to the buoy, wherein the position sensing unit includes a satellite signal receiver which computes location data in response to receiving signals from multiple satellites, and a transmitter which transmits the location data. A tracking device can be used to display the location data received from the position sensing unit, allowing the position of the buoy and associated underwater animal trap to be tracked. A method of tracking an underwater animal trap is disclosed which includes coupling a position sensing unit to a buoy, and tracking the location of the buoy with a tracking unit. The buoy is coupled to an underwater animal trap, and the position sensing unit computes buoy location data in response to receiving signals from multiple satellites.

Abstract: A seismic survey system for performing offset borehole seismic survey measurement operations. The system may include a first seismic survey subsystem having a first wireless digital communication device and a second seismic survey subsystem having a second wireless digital communication device and remotely located from the first seismic survey subsystem. The first and second digital communication devices may be configured to provide a digital communication link for transporting digital information between the first seismic survey subsystem and second seismic survey subsystem. The system may be configured to enable a user at the first seismic survey subsystem to remotely modify at least a portion of a first plurality of operating parameters associated with at least one source signal device located at the second seismic survey subsystem. The system may also be configured to utilize GPS information in order to improve accuracy of source signal firing timing synchronization.

Abstract: The invention relates to a process for marine seismic exploration at least two different depths by means of streamers, each including a set of hydrophones, the acquisition of data at the different depths being performed in a single exploration region, and in which the position of the streamers and the hydrophones when acquiring seismic data at a first depth is independent of the position of the streamers and hydrophones when acquiring seismic data at a second depth.

Abstract: A seismic survey is conducted by positioning an array of remote acquisition units (RAUs). Each of the RAUs records seismic data derived from one or more geophones in digital form in local memory. The data is collected by a harvester unit traversed across the survey territory as by an aircraft using point-multipoint communications, and subsequently transferred from the harvester unit to a central control unit.

Abstract: In some aspects of the invention, a method of generating a beam of acoustic energy in a borehole is disclosed.

Abstract: A technique includes distributing particle motion sensors along the length of a seismic streamer. Each particle motion sensor is eccentrically disposed at an associated angle about an axis of the seismic streamer with respect to a reference line that is common to the associated angles. The sensors are mounted to suppress torque noise in measurements that are acquired by the particle motion sensors. This mounting includes substantially varying the associated angles.