Abstract: System and method for generating discrete dithering sequences DSi for marine seismic sources Si in a marine acquisition system. The method includes determining a number N of the seismic sources Si to be fired; calculating a dithering sequence DSi for each source Si such that when any two consecutive source activation Sk and Sl, where l=k+1, are selected, a combination DSkl of their dithering sequences DSk and DSl is a uniform random low-discrepancy sequence; and driving each source Si with the corresponding dithering sequence DSi to generate blended seismic data.

Abstract: A reaction mass seismic survey source that is located in an underground casing. The seismic source includes a non-planar base plate; a reaction mass located on the non-planar base plate; and a flextensional element housed in a recess of the reaction mass and configured to vibrate the non-planar base plate when actuated, to generate seismic waves underground.

Abstract: An electromagnetic (EM) receiver system for measuring EM signals. The EM receiver system includes a platform; a coil for measuring EM signals; and first to third suspension mechanisms located between the platform and the coil so that the coil oscillates relative to the platform, and the first to third suspension mechanisms attenuate motion induced noise introduced by towing the receiver system above ground.

Abstract: Device and method for calculating a set of surface wave dispersion curves. The method includes receiving seismic data recorded with seismic sensors over an area to be surveyed; selecting region units that cover the area to be surveyed; gathering traces for the region units; processing in a computing device the traces to obtain a set of candidate measurements for each region unit; teaching a decision algorithm based on a first subset of the set of candidate measurements; and calculating the set of surface wave dispersion curves by running the decision algorithm on a second subset of the set of candidate measurements.

Abstract: The present disclosure includes a method for suppressing 4D noise. The method includes calculating a first similarity map based on the similarity of one of one or more first 3D images and a second 3D image. The first and second 3D images are derived from first and second surveys, respectively. The method also includes calculating a second similarity map based on the similarity of one of the one or more first 3D images and a third 3D image, which is derived from the second survey. The method also includes calculating a third similarity map based on the similarity of first and second 4D images, which are based on differences between the 3D images. The method also includes generating a composite 4D image based at least on the first, second, and third similarity maps. The present disclosure may also include associated systems and apparatus.

Abstract: Multi-vintage energy mapping selects a first seismic survey data and a second seismic survey dataset from a plurality of seismic survey datasets. The first seismic survey dataset includes a set of first energies associated with a first seismic survey geometry, and the second seismic survey dataset includes a set of second energies associated with a second seismic survey geometry. The first set of energies are mapped from the first seismic survey geometry to the second seismic survey geometry, and the second set of energies are mapped from the second seismic survey geometry to the first seismic survey geometry. An updated first seismic dataset and an updated second seismic dataset are generated such that only energies from the first and second seismic datasets associated with changes in a subsurface are preserved in the updated first and second seismic datasets.

Abstract: A method for estimating a time variant signal representing a seismic source obtains seismic data recorded by at least one receiver and generated by the seismic source, the recorded seismic data comprising direct arrivals and derives the time variant signal using an operator that relates the time variant signal to the acquired seismic data, the operator constrained such that the time variant signal is sparse in time.

Abstract: Method and seismic source for generating seismic waves in a borehole. The seismic source includes a housing; an actuator mechanism located inside the housing and configured to generate a fluctuating pressure; a flexible membrane attached to the housing and configured to hold a fluid; and a coupling device covered by the flexible membrane and configured to generate a static pressure on the flexible membrane.

Abstract: System and method for estimating a spatial distribution of a characteristic associated with Earth resources. The method includes receiving at an interface palaeogeography data including (1) palaeotopography data, (2) palaeobathymetry data, (3) and a palaeo-earth systems model; calculating with a processor, a retrodictive model of the characteristic based on the (1) palaeotopography data, (2) the palaeobathymetry data, and (3) the palaeo-earth systems model; and imaging the spatial distribution of the characteristic over a part of the Earth.

Abstract: An autonomous underwater vehicle (AUV) for guiding other AUVs during a marine seismic survey. The guiding AUV includes a housing; a propulsion system located inside the housing; and an acoustic positioning system attached to an outside the housing. The acoustic positioning system emits at least three chirps from three different locations.

Abstract: Systems and methods for to two dimensional gravity modeling with variable densities are disclosed. The methods may include a method of modeling the density of a subsurface formation is disclosed. The methods may include generating a plurality of cells in a cross section of density values corresponding to a subsurface formation. The methods may further include assigning a density value to each cell. The methods may further include calculating a gravity effect for each cell based upon the density value. The methods may further include recording the gravity effect for each cell in a data structure.

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: A method for estimating surface waves generates incident, back-scattered, virtual back-scattered and super-virtual back-scattered traces. The stacked super-virtual back-scattered traces are an estimate of the surface waves.

Abstract: A method for steering a marine seismic acquisition system by determining a steering point associated with towed seismic equipment is described. Coverage boundaries for a current line in a seismic survey and for an already acquired adjacent line in the seismic survey are computed. Cross-line distances between the coverage boundary for the current line and the coverage boundary for the adjacent line are computed based on a set of specifications for the seismic survey. A steering point associated with towed seismic equipment is determined based on the computed cross-line distances. A least one steering command for a steering element in the marine seismic acquisition system is generated based on the determined steering point.

Abstract: Modeling an elastic stiffness tensor in a transverse isotropic subsurface medium acquires well log data for at least one well passing through the transverse isotropic subsurface medium. The transverse isotropic subsurface medium is divided into an effective anisotropic layer and an isotropic layer. The effective anisotropic layer elastic parameters are modeled, and the isotropic layer elastic parameters are modeled using the effective anisotropic layer elastic parameters and the acquired well log data. The modeled effective anisotropic layer elastic parameters and the modeled isotropic layer elastic parameters are used to upscale the effective anisotropic layer and the isotropic layer into the transverse isotropic subsurface medium comprising a single layer and to determine the five members of the elastic stiffness tensor for the transverse isotropic subsurface medium.

Abstract: Properties of underground formations are obtained by performing simultaneous geostatistical inversion of two or more seismic datasets acquired over the same area. These methods enable simultaneous estimating quantitative changes in a hydrocarbon-producing field.

Abstract: A device and method for calculating electrical properties of a surveyed underground formation. The method includes selecting a waveform having multiple current transition rates; placing a time-domain electromagnetic (TEM) system above the underground formation while generating with a transmitter a transient primary magnetic field during an on-time period and no magnetic field during a following off-time period, due to the waveform; and recording with a receiver magnetic related data generated by the earth as a result of the transient primary magnetic field. The receiver records the magnetic related data during the on-time period using plural on-time gates sampling.

Abstract: Computing device, software and method for calibrating pilot and drive signals of a marine seismic source array using measured data. The method includes receiving a source array geometry and a model of the source array; estimating an initial overall response of the source array based on numerical simulations, the model of the source array, and the source array geometry; generating the pilot and drive signals for the source array based on the initial overall response; determining individual responses of the source elements, which form the source array, based on the source array geometry, the model of the source array, and first measured data; calculating an actual overall response of the source array based on the pilot and drive signals, the model of the source array and second measured data; and adjusting the pilot and drive signals based on the actual overall response of the source array.

Abstract: Surface wave coda in seismic data recorded with a data acquisition system over an underground formation is estimated using time-reversal experiments. First time-reversal experiments use a first time-reversal mirror including a target source and one or more other sources to obtain estimates of surface waves traveling from other receivers to a target receiver. Second time-reversal experiments obtain a coda estimate for a surface wave traveling from the target source to the target receiver using a second time-reversal mirror including the target receiver and the other receivers.

Abstract: Methods and systems for deriving S-wave velocity information from the low-frequency content of ambient noise are described. The ambient noise can be collected on a dedicated record or on a production record associated with the receivers of a three-dimensional seismic survey. The methods and systems use one of a plurality of analysis models selected based on quality factors of the ambient noise data. The methods and systems analyze the data at a plurality of single frequencies then transform the velocity versus frequency data into velocity versus depth data.