Abstract: Methods for characterizing a geological formation, the methods include retrieving measured data provided by a measuring tool along one or more logged borehole length for a borehole, another borehole or both in order to produce a borehole imaging log. Selecting depth-defined intervals of the borehole imaging log as training images for inputting in a multi-point geostatistical model. Determining pattern based simulations for each training image using a pixel-based template of the multi-point geostatistical model so as to obtain training image patterns. Using the pattern based simulation of each training image to assign to each of the training image a corresponding training image pattern. Constructing from the training image patterns one or more fullbore image log of a borehole wall of the borehole. Repeat the second to fourth steps through the one or more logged borehole length in order to construct fullbore images from successive, adjacent training images.

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: A system. At least some illustrative embodiments are a system including a first survey vessel and a first tow line coupled to the first survey vessel. A first sensor streamer is coupled to the first tow line. Also includes are a second survey vessel and a second tow line coupled to the second survey vessel. A second sensor streamer is coupled to the second tow line and a pulling line is connected between the first tow line and the second tow line.

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: In some aspects, a first boundary is computed based on microseismic event locations associated with a first stage of a multi-stage injection treatment of a subterranean region. A second boundary is computed based on microseismic event locations associated with a second stage of the multi-stage injection treatment. Based on the first and second boundaries, an overlap between stimulated reservoir volumes (SRVs) associated with the first and second stages is determined.

Abstract: In some aspects, a boundary is computed based on locations of microseismic events associated with a stimulation treatment of a subterranean region. A major axis of a stimulated reservoir volume (SRV) for the stimulation treatment is identified based on the boundary. In some examples, the boundary is an ellipsoid, and the major axis of the ellipsoid is identified.

Abstract: An exploration paradigm for detecting and/or characterizing gas hydrate deposits using either electromagnetic or seismic surveys, that accounts for the possibility that gas hydrate may accumulate in vertical or subvertical dikes. Geologic factors, such as the presence of the gas hydrate stability zone, indications that a prolific source of gas exists (or existed) below the gas hydrate stability zone and indications that a high flux of gas could be transported into the gas hydrate stability zone, may be considered as part of an exploration strategy. Data may be collected using seismic techniques, such as a walk-away vertical seismic profile techniques, or electromagnetic surveys that are adapted to detecting the presence of vertical or subvertical dikes. In one example, data processing and acquisition techniques may be adapted to detect hydrate dikes, and do not assume a horizontally isotropic earth model.

Abstract: A buoy for recording seismic signals while underwater. The buoy includes a body; a buoyancy system configured to control a buoyancy of the body to descend to a predetermined depth (H1); a propulsion system configured to actively adjust a position of the body at a given position (X, Y); a seismic sensor located on the body and configured to record the seismic signals; and a control device configured to control the buoyancy system to maintain the body substantially at the predetermined depth (H1) and to control the propulsion system to maintain the body substantially at the given position (X, Y) while the buoy records seismic data, and also to instruct the seismic sensor when to record seismic signals.

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.

Abstract: To acquire near-zero offset survey data, a survey source and a first streamer attached to the survey source are provided, where the first streamer has at least one survey receiver. A second streamer separate from the survey source and the first streamer includes survey receivers. Near-zero offset data is measured using the at least one survey receiver of the first streamer.

Abstract: Maximum and minimum horizontal stresses are estimated using radial profiles of shear moduli for a deviated borehole. Inversion enables estimation of maximum and minimum horizontal stresses using radial profiles of three shear moduli associated with an orthogonal set of axis defined by the deviated borehole azimuth from the North and the deviation of the longitudinal axis of the borehole from the vertical.

Abstract: A system and method are provided for determining shallow water multiples when seismically exploring a geographical area of interest under a body of water. The system and method estimate a multi-channel prediction operator F using a model of water layer related multiples with respect to received and stored seismic data, estimate a travel time of the transmitted seismic wavelets from the one or more sources to each of the plurality of receivers, and then generate water layer primary reflections models using the estimated travel time and Green's function. The system and method then merge the generated water layer primary reflections models with the multi-channel prediction operator F to create a hybrid multi-channel prediction operator FH, and convolute the hybrid multi-channel prediction operator FH with the stored received data to determine a final multiples model.

Abstract: Methods and related systems are described for measuring acoustic signals in a borehole during a fracturing operation. The system includes a downhole toolstring designed and adapted for deployment in a borehole formed within a subterranean rock formation. A downhole rock fracturing tool opens and propagates a fracture in the subterranean rock formation. Dipole and/or quadrupole acoustic sources transmit acoustic energy into the subterranean rock formation. A receiver array measures acoustic energy traveling through the subterranean rock formation before, during and after the fracture induction. Geophones mounted on extendable arms can be used to measure shear wave acoustic energy travelling in the rock formation. The toolstring can be constructed such that the sources and receivers straddle the fracture zone during the fracturing.

Abstract: A seismic survey system for surveying a subsurface. The system includes a volumetric land source buried underground for generating P-waves; a non-volumetric land source buried underground for generating P- and S-waves; plural receivers distributed about the volumetric and non-volumetric land sources and configured to record seismic signals corresponding to the P- and S-waves; and a controller connected to the volumetric land source and the non-volumetric land source and configured to shot them in a given pattern.

Abstract: A seismic survey system for recording seismic data underwater. The system includes first plural buoys configured to descend to a first predetermined depth (H1) in water, at least one buoy having a seismic receiver for recording the seismic data; a first vessel configured to launch the first plural buoys; and a first acoustic system attached to the first vessel and configured to detect a position of the at least one buoy while underwater. The at least one buoy is instructed to maintain the first predetermined depth (H1) underwater while recording the seismic data.

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: A seismic survey system for recording seismic data underwater in the presence of underwater currents. The system includes first plural buoys configured to descend in water at a predetermined depth (H1) and each having a seismic receiver for recording the seismic data; a first vessel configured to launch the first plural buoys along a first line; and a second vessel configured to recover the first plural buoys at a second line, wherein there is a predetermined distance between the first and second lines. The first plural buoys are configured to travel underwater, at substantially the first predetermined depth (H1), from the first line to the second line, due exclusively to the underwater currents.

Abstract: Dual-sensor seismic data are separated into aliased and unaliased parts in a frequency-wavenumber domain. The seismic data in the unaliased part are processed using a conventional vertical wavenumber. The seismic data in the aliased part are processed using an alternative vertical wavenumber additionally based on a Nyquist wavenumber for the seismic data. The processed unaliased seismic data and the processed aliased seismic data are combined.

Abstract: Location of underwater moving target device carrying a receiver configured to detect acoustic waves emitted at a known location is estimated such that to be consistent with detected velocity and orientation of the target device, and with a current phase of a signal corresponding to the acoustic waves detected at the target device. A stack including one or more boxes obtained by applying contractors to location boxes is output as the estimate of the location of the moving target device.

Abstract: Method for building a subsalt velocity model. In one implementation, the method may include determining a velocity of a sedimentary area surrounding a salt body, determining an initial velocity of a subsalt sedimentary area disposed below the salt body by interpolating the velocity of the surrounding sedimentary area with one or more boundaries defining the salt body, and updating the initial velocity of the subsalt sedimentary area.