Abstract: Inversion of enhanced-sensitivity controlled source electromagnetic data can include combining measured controlled source electromagnetic (CSEM) data onto a common set of virtual receiver positions for each of a plurality of positions of a source along a survey path, determining a steering vector that enhances a sensitivity of the measured CSEM data to a subsurface resistivity variation, and performing an inversion using the measured CSEM data and modeled CSEM data, each having the steering vector applied thereto as a data weight, to better identify the subsurface resistivity variation.

Abstract: Disclosed are methods and systems for producing bipole source modeling with reduced computational loads. A method may comprise receiving first electromagnetic data and second electromagnetic data from a first shotpoint and a second of a marine electromagnetic survey, modelling a first electromagnetic field and second electromagnetic field for one or more dipole sources of a bipole source and combining a plurality of data points to provide an approximation of an electromagnetic field for the bipole source. A system may comprise electromagnetic sensors, a bipole source, wherein the bipole source comprise a pair of electrodes that are separated by a distance, wherein the bipole source is configured to generate an electromagnetic field, and a data processing system configured to receive electromagnetic data from a plurality of shotpoints of the bipole source and model electromagnetic fields for one or more dipole sources of the bipole source from the electromagnetic data.

Abstract: Methods of geophysical modeling and inversion are disclosed. A sparse domain is defined for a geophysical model, over which a sparse model result is computed. A full model result is then resolved by interpolation over the sparse domain. The full model result may be used as the forward modeling result in a geophysical inversion process. Reconstruction error, or model error, or both may be used to adjust the sparse domain, the model, or the geophysical basis of the model.

Abstract: A method for jointly inverting subsurface resistivities and noise parameters that may comprise the steps of identifying electromagnetic data acquired from one or more electromagnetic sensors, wherein the electromagnetic data includes a source-generated signal and noise, and jointly inverting at least subsurface resistivities and noise parameters based on the electromagnetic data. A marine electromagnetic survey system, that may comprise a data processing system configured to identify electromagnetic data acquired from one or more electromagnetic sensors, wherein the electromagnetic data includes a source-generated signal and noise and jointly invert subsurface resistivities and noise based on the electromagnetic data.

Abstract: Inducing vibrations onto a sensor streamer. At least some of the example embodiments are methods including: towing a sensor streamer through a body of water, the sensor streamer comprising a plurality of geophones spaced along the sensor streamer; inducing a vibration onto the sensor streamer at a predetermined location, the inducing as the sensor streamer is towed; measuring the vibration by a geophone at a distance from the predetermined location, the measuring creates a measured vibration; and creating, by a computer system, a model of noise propagation along the sensor streamer, the creating based on the measured vibration.

Abstract: Suppressing data corresponding to noise using a model of noise propagation along a sensor streamer. At least some of the example embodiments are methods including: reading a data set containing noise and seismic signals recorded by geophones disposed in a sensor streamer when the sensor streamer was within a body of water; determining locations of noise sources along the sensor streamer when the sensor streamer was within the body of water; and suppressing data of the data set corresponding to noise sources along the sensor streamer.

Abstract: Inversion of enhanced-sensitivity controlled source electromagnetic data can include combining measured controlled source electromagnetic (CSEM) data onto a common set of virtual receiver positions for each of a plurality of positions of a source along a survey path, determining a steering vector that enhances a sensitivity of the measured CSEM data to a subsurface resistivity variation, and performing an inversion using the measured CSEM data and modeled CSEM data, each having the steering vector applied thereto as a data weight, to better identify the subsurface resistivity variation.

Abstract: Aspects described herein provide for a sensor assembly having an electrically isolated cable segment that may be used for geophysical prospecting. The sensor assembly generally includes a first cable segment comprising at least one electromagnetic (EM) sensor, and a second cable segment connected to the first cable segment and electrically isolated from the first cable segment. The second cable segment may be free of electrically conductive components. Alternatively, the second cable segment may have electrically conductive components that are not electrically connected to the first cable segment. The electrically isolated cable segment may reduce or eliminate undesired signal cross-feed from the EM source to the first cable segment, which may aid in maintaining data quality.

Abstract: Disclosed are methods and systems for producing bipole source modeling with reduced computational loads. A method may comprise receiving first electromagnetic data and second electromagnetic data from a first shotpoint and a second of a marine electromagnetic survey, modelling a first electromagnetic field and second electromagnetic field for one or more dipole sources of a bipole source and combining a plurality of data points to provide an approximation of an electromagnetic field for the bipole source. A system may comprise electromagnetic sensors, a bipole source, wherein the bipole source comprise a pair of electrodes that are separated by a distance, wherein the bipole source is configured to generate an electromagnetic field, and a data processing system configured to receive electromagnetic data from a plurality of shotpoints of the bipole source and model electromagnetic fields for one or more dipole sources of the bipole source from the electromagnetic data.

Abstract: Methods of geophysical modeling and inversion are disclosed. A sparse domain is defined for a geophysical model, over which a sparse model result is computed. A full model result is then resolved by interpolation over the sparse domain. The full model result may be used as the forward modeling result in a geophysical inversion process. Reconstruction error, or model error, or both may be used to adjust the sparse domain, the model, or the geophysical basis of the model.

Abstract: Methods of geophysical modeling and inversion are disclosed. A sparse domain is defined for a geophysical model, over which a sparse model result is computed. A full model result is then resolved by interpolation over the sparse domain. The full model result may be used as the forward modeling result in a geophysical inversion process. Reconstruction error, or model error, or both may be used to adjust the sparse domain, the model, or the geophysical basis of the model.

Abstract: Suppressing data corresponding to noise using a model of noise propagation along a sensor streamer. At least some of the example embodiments are methods including: reading a data set containing noise and seismic signals recorded by geophones disposed in a sensor streamer when the sensor streamer was within a body of water; determining locations of noise sources along the sensor streamer when the sensor streamer was within the body of water; and suppressing data of the data set corresponding to noise sources along the sensor streamer.

Abstract: Inducing vibrations onto a sensor streamer. At least some of the example embodiments are methods including: towing a sensor streamer through a body of water, the sensor streamer comprising a plurality of geophones spaced along the sensor streamer; inducing a vibration onto the sensor streamer at a predetermined location, the inducing as the sensor streamer is towed; measuring the vibration by a geophone at a distance from the predetermined location, the measuring creates a measured vibration; and creating, by a computer system, a model of noise propagation along the sensor streamer, the creating based on the measured vibration.

Abstract: A method for jointly inverting subsurface resistivities and noise parameters that may comprise the steps of identifying electromagnetic data acquired from one or more electromagnetic sensors, wherein the electromagnetic data includes a source-generated signal and noise, and jointly inverting at least subsurface resistivities and noise parameters based on the electromagnetic data. A marine electromagnetic survey system, that may comprise a data processing system configured to identify electromagnetic data acquired from one or more electromagnetic sensors, wherein the electromagnetic data includes a source-generated signal and noise and jointly invert subsurface resistivities and noise based on the electromagnetic data.

Abstract: Aspects described herein provide for a sensor assembly having an electrically isolated cable segment that may be used for geophysical prospecting. The sensor assembly generally includes a first cable segment comprising at least one electromagnetic (EM) sensor, and a second cable segment connected to the first cable segment and electrically isolated from the first cable segment. The second cable segment may be free of electrically conductive components. Alternatively, the second cable segment may have electrically conductive components that are not electrically connected to the first cable segment. The electrically isolated cable segment may reduce or eliminate undesired signal cross-feed from the EM source to the first cable segment, which may aid in maintaining data quality.

Abstract: Disclosed are methods and systems for suppression of noise in electromagnetic surveying that includes stacking two or more frames of electromagnetic data. An example embodiment discloses a method for suppressing swell-induced noise in an electromagnetic survey, comprising: measuring an electromagnetic field parameter at one or more positions to provide an electromagnetic signal, the electromagnetic signal comprising a swell-induced portion; and stacking two or more frames of the electromagnetic signal to provide a stacked signal in which the swell-induced portion is suppressed, wherein the swell-induced portion is out of phase between the two or more frames.