Abstract: A method for conducting seismic operations includes the steps of deploying a seismic streamer carrying an electrically powered device from a vessel into water having waves, providing an in-sea generator in electrical connection with the device, producing electricity from the in-sea generator by harvesting mechanical energy from the waves, and providing the produced electricity to the device.

Abstract: A method of controlling a streamer positioning device (18) configured to be attached to a marine seismic streamer (12) and towed by seismic survey vessel (10) and having a wing and a wing motor for changing the orientation of the wing. The method includes the steps of: obtaining an estimated velocity of the streamer positioning device, calculating a desired change in the orientation of the wing using the estimated velocity of the streamer positioning device, and actuating the wing motor to produce the desired change in the orientation of the wing. The invention also involves an apparatus for controlling a streamer positioning device including means for obtaining an estimated velocity of the streamer positioning device, means for calculating a desired change in the orientation of the wing using the estimated velocity of the streamer positioning device, and means for actuating the wing motor to produce the desired change in the orientation of the wing.

Abstract: The invention relates to a method of seismic data processing, wherein the data includes a set of seismic traces, with each trace including a signal that has been recorded by a sensor after having been propagated in a subsurface area, with the signal being defined by an amplitude as a function of time, including the steps of: migration of data according to an initial time-velocity model, picking in the time-migrated data one or more event(s) corresponding to one or more subsurface reflector(s) so as to obtain facets locally approximating the event, kinematic demigration of the facets plotted so as to obtain simplified seismic data in the form of a set of facets and a set of attributes associated with the facets.

Abstract: Method for separating signals recorded by a seismic receiver and generated with at least two vibratory seismic sources driven with no listening time. The method includes receiving seismic data that includes data d recorded by the seismic receiver and data related to the first and second vibratory seismic sources; computing a source separation matrix based on the data related to the first and second vibratory seismic sources; calculating first and second earth impulse responses HA and HB corresponding to the two vibratory seismic sources, respectively, based on the data d recorded by the seismic receiver, the data related to the two vibratory seismic sources and the source separation matrix; and separating the signals recorded by the seismic receiver based on the first and second earth impulse responses HA and HB such that signals the two vibratory seismic sources are disentangled.

Abstract: Techniques are disclosed for performing time-lapse monitor surveys with sparsely sampled monitor data sets. An accurate 3D representation (e.g., image) of a target area (e.g., a hydrocarbon bearing subsurface reservoir) is constructed (12) using the sparsely sampled monitor data set (11). The sparsely sampled monitor data set may be so limited that it alone is insufficient to generate an accurate 3D representation of the target area, but accuracy is enabled through use of certain external information (14). The external information may be one or more alternative predicted models (25) that are representative of different predictions regarding how the target area may change over a lapse of time. The alternative models may, for example, reflect differences in permeability of at least a portion of the target area. The sparsely sampled monitor data set may then be processed to determine (23) which of the alternative models is representative of the target area.

Abstract: Techniques are disclosed for performing time-lapse seismic monitor surveys with sparsely sampled monitor data sets. A more accurate 3D representation (e.g., image) of a target area (e.g., a hydrocarbon bearing subsurface reservoir) is constructed using the sparsely sampled monitor data set (11). The sparsely sampled monitor data set may be so limited that it alone is insufficient to generate an accurate 3D representation of the target area, but accuracy is achieved through use of certain external information (14). The external information may include information accurately identifying a shape of the seismic reflector(s) present in the target area. The shape may be predetermined from a fully sampled base survey, and used to enable an accurate 3D representation (12) of the target area to be later generated for a monitor survey using a sparsely sampled monitor data set.

Abstract: Systems and methods create a velocity model for well time-depth conversion. In one implementation, a system optimizes a time-depth relationship applied to data points from a single well to estimate coefficients for a velocity 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 without undue dependence on the boundary conditions. The system can optimize estimation of a rate of increase in velocity to enable the velocity function to go through a data point on each top horizon. The system may also estimate each base horizon from trends in the data points and adjust the velocity function to go through a data point on each base horizon.

Abstract: A computer-implemented method includes providing a first velocity model obtained from a vertical seismic profile survey representative of an upper region of a subterranean formation. Wavefields from the first velocity model are datumed using wave equations to a datum line between the upper region and a target area beneath the upper region to obtain datumed wavefields. The method further includes obtaining interferometric common shot data and interferometric common midpoint data from the datumed wavefield using wave equations at the datum line. The first velocity model, the datumed wavefield, wavefield equations, and the interferometric common midpoint data are then used to generate a second velocity model representative of velocities in the target area.

Abstract: System and method for providing an anti-fouling function to a streamer to be towed under water for seismic survey data collection. The method includes mixing a thermoplastic material with a biocide material to form an external sheath material; and forming an external sheath over a main sheath of the streamer to provide the anti-fouling function. The external sheath is formed from the external sheath material such that the biocide material is distributed throughout the external sheath.

Abstract: Methods and systems for variable wavelet correction are described. A variable depth dataset is deghosted before presentation to a multiples prediction step of multiples elimination model. In another aspect, the multiples prediction is reghosted before presentation to an adaptive subtraction step of the multiples elimination model. A source-side zero-phasing signature can be applied before deghosting and a predefined gain can be applied in the low and high frequency sides as part of deghosting and reghosting to compensate for the squaring effect produced by convolving wavelets.

Abstract: A low frequency sound source has a radiating piston (3) of the order of a few meters across backed by a gas spring (13, 15) containing a fixed mass of gas. The gas pressure in the spring is kept at levels for which the natural frequency of the piston (3) loaded by the fluid (41) lies in the seismic band and may be as low as 0.5 Hz. The piston (3) is given an initial displacement and begins to oscillate. Its oscillations are sustained by an actuator (27, 29) whose drive signal is derived from the velocity of the piston (5) via a velocity or displacement sensor. The sound source is caused to perform a frequency sweep by gradually compressing the gas in the gas spring (13, 15) so that the spring becomes stiffer both because of the rising pressure and because of the reducing length of the gas spring spaces (13, 15). This double effect allows large changes in stiffness to be produced and hence allows the source to operate over at least three octaves of frequency.

Abstract: A method for selecting a signal arrival for determining an accurate position of seismic equipment includes the steps of transmitting a signal from a pinger; predicting a direct arrival and a reflected arrival of the signal at a receiver, wherein each arrival is the time between the transmission of the signal to reception of the signal; measuring arrivals of the signal at the receiver; selecting the measured signal arrival that is similar to the predicted direct arrival as a preliminary signal arrival; defining a confidence interval for the actual direct arrival of the signal based on the predicted direct arrival and the predicted reflected arrival; and finalizing the signal arrival, wherein the selected preliminary signal arrival is the finalized signal arrival if it is within the confidence interval.

Abstract: Marine seismic survey using an array (6) of streamers (8) towed behind a vessel (2) and carrying acoustic sources (4) and sensors (10), spreading means (12, 14, 22, 23, 24) for keeping the streamers (8) at a given distance by lateral tensioning, and bridles (16) for connecting the spreading means and towing ropes and cables. The bridles (16) are comprising at least one solid link or connection device (26) for releasable connection to lines under tension and extending in different directions.

Abstract: Systems and methods for modeling a three-dimensional (3D) geological structure to improve maximum continuity interpolation. An integration method describes local anisotropic effects and introduces interpolation techniques to perform the interpolation between two points of interest along a direction of maximum continuity and across fault surfaces.

Abstract: One or more embodiments and methods of analyzing a formation sample with in a coring tool are disclosed herein. The methods and embodiments may include extracting a first core from a sidewall of a wellbore with a coring tool at a first depth, ultrasonically measuring a sound speed of the first core, transmitting the ultrasonically measured sound speed of the first core to a surface display unit, analyzing the ultrasonically measured sound speed in real time, determining the quality of the first core, extracting a second core at the first depth if the first core is determined to be low quality, and extracting the second core at a second depth if the core first is determined to be high quality.

Abstract: Method for generating an excitation signal for a first vibratory seismic source so that the first vibratory seismic source is driven with no listening time. The method includes a step of determining a first target spectrum for the first vibratory seismic source; a step of setting a first group of constraints for the first vibratory seismic source; and a step of generating a first excitation signal for the first vibratory seismic source based on the first group of constraints and the first target spectrum. The first seismic traces recorded with plural receivers can be identified when the first vibratory seismic source is driven with no listening time, based on the first excitation signal.

Abstract: A method and apparatus for a method for generating an estimated value of absorption parameter Q(t). In one embodiment, the method includes receiving an input seismic trace, applying a time variant Fourier transform to the input seismic trace to generate a time variant amplitude spectrum of the input seismic trace, dividing the natural logarithm of the time variant amplitude spectrum by ??f, and performing a power series approximation to the result with an index starting from one to generate an estimated value of R(t). R(t) is a ratio between traveltime t and the absorption parameter Q(t). The method further includes dividing t by R(t) to generate the estimated value of the absorption parameter Q(t).

Abstract: A method and apparatus for predicting a plurality of surface multiples for a plurality of traces in a record of seismic data. In one embodiment, the method includes providing a plurality of target traces at a nominal offset and a nominal azimuth; selecting a plurality of pairs of input traces, wherein the midpoints of the input traces in each pair are separated by half the nominal offset and the azimuth of a line connecting the midpoints of the input traces in each pair is equal to the nominal azimuth; convolving the selected pairs of input traces to generate a plurality of convolutions; and applying a three dimensional operator to the convolutions.

Abstract: The method presented accounts for three-dimensional effects when deghosting marine seismic data. The method relies on having second-order spatial derivatives in the cross-line direction available. The second-order cross-line derivative can be estimated directly or through indirect measurements of other wavefield quantities and by using wave-equation techniques to compute the desired term. The method preferably employs either a multicomponent streamer towed in the vicinity of the sea surface, a twin-streamer configuration near the sea-surface, or a configuration of three streamers that are separated either vertically or horizontally to estimate the second-order vertical derivative of pressure.

Abstract: A system and methods for acquiring seismic data is provided. In one aspect, the system and methods utilize a plurality of field service units placed over a region of interest, a repeater unit that wirelessly communicates with the field service units and a remote unit for controlling and processing the seismic data acquired by the field service units. In one aspect, the system and methods determine a condition associated with each of a plurality of attributes relating to acquisition of the seismic data at each field service unit, generate messages at each field service unit when the condition of a particular attribute meets a selected criterion, transmit the generated messages, receive the messages transmitted by at least a group of field service units at a repeater unit placed in the region of interest, analyze the messages received from the group of field service units at the repeater unit and then transmit information relating to the received messages to the remote unit for further processing.