Abstract: Systems and methods for acquiring and processing electromagnetic data in subsurface formations. In one example, a system includes an electromagnetic source, a plurality of electromagnetic receivers, and an electromagnetic data processor. The electromagnetic source is configured to generate an electromagnetic pulse that induces electromagnetic energy in subsurface formations. The electromagnetic receivers are configured to detect the electromagnetic energy reflected by the subsurface formations, and to output signals corresponding to detected electromagnetic energy reflected by the subsurface formations. The electromagnetic data processor configured to process, based on differences in travel times of the electromagnetic energy between the subsurface formations and the electromagnetic receivers, the signals output by the electromagnetic receivers.

Abstract: Systems and methods for acquiring and processing electromagnetic data in subsurface formations. In one example, a system includes an electromagnetic source, a plurality of electromagnetic receivers, and an electromagnetic data processor. The electromagnetic source is configured to generate an electromagnetic pulse that induces electromagnetic energy in subsurface formations. The electromagnetic receivers are configured to detect the electromagnetic energy reflected by the subsurface formations, and to output signals corresponding to detected electromagnetic energy reflected by the subsurface formations. The electromagnetic data processor configured to process, based on differences in travel times of the electromagnetic energy between the subsurface formations and the electromagnetic receivers, the signals output by the electromagnetic receivers.

Abstract: A system and method for estimating seismic anisotropy of subsurface formations with high resolution. A method for determining anisotropy parameters of subsurface formations includes generating a synthetic reflectivity gather from a vertical well log. Times of a surface seismic gather are adjusted to those of the synthetic gather. Low-cut filtering is applied to the surface seismic gather. Anisotropy parameters are generated as a difference of the filtered seismic gather and the synthetic gather. An anisotropy value is assigned to each of plurality of layers of a formation based on the generated anisotropy parameters.

Abstract: A system and method for estimating seismic anisotropy of subsurface formations with high resolution. A method for determining anisotropy parameters of subsurface formations includes generating a synthetic reflectivity gather from a vertical well log. Times of a surface seismic gather are adjusted to those of the synthetic gather. Low-cut filtering is applied to the surface seismic gather. Anisotropy parameters are generated as a difference of the filtered seismic gather and the synthetic gather. An anisotropy value is assigned to each of plurality of layers of a formation based on the generated anisotropy parameters.

Abstract: A method for determining orientation of an electromagnetic survey sensor includes deploying the sensor at a selected position on the bottom of a body of water. An electromagnetic field is generated at a selected position in the body of water. A portion of the electromagnetic field is detected along at least two orthogonal directions at the sensor. A portion of the detected electromagnetic field is selected as having traveled only in a vertical plane which includes both source position and sensor position. The polarization direction of the selected portion of the electromagnetic field is determined from the selected portion. The determined polarization direction is used to determine the sensor orientation.

Abstract: There is provided herein a system and method of acquiring, processing, and imaging transient Controlled Source ElectroMagnetic (t-CSEM) data in ways that are similar to those used for seismic data. In particular, the instant invention exploits the time-distance characteristics of t-CSEM data to permit the design and execution of t-CSEM surveys for optimal subsequent processing and imaging. The instant invention illustrates how to correct t-CSEM data traces for attenuation and dispersion, so that their characteristics are more like those of seismic data and can be processed using algorithms familiar to the seismic processor. The resulting t-CSEM images, particularly if combined with corresponding seismic images, may be used to infer the location of hydrocarbon reservoirs.

Abstract: A method for determining orientation of an electromagnetic survey sensor includes deploying the sensor at a selected position on the bottom of a body of water. An electromagnetic field is generated at a selected position in the body of water. A portion of the electromagnetic field is detected along at least two orthogonal directions at the sensor. A portion of the detected electromagnetic field is selected as having traveled only in a vertical plane which includes both source position and sensor position. The polarization direction of the selected portion of the electromagnetic field is determined from the selected portion. The determined polarization direction is used to determine the sensor orientation.

Abstract: There is provided herein a system and method of acquiring, processing, and imaging transient Controlled Source ElectroMagnetic (t-CSEM) data in ways that are similar to those used for seismic data. In particular, the instant invention exploits the time-distance characteristics of t-CSEM data to permit the design and execution of t-CSEM surveys for optimal subsequent processing and imaging. The instant invention illustrates how to correct t-CSEM data traces for attenuation and dispersion, so that their characteristics are more like those of seismic data and can be processed using algorithms familiar to the seismic processor. The resulting t-CSEM images, particularly if combined with corresponding seismic images, may be used to infer the location of hydrocarbon reservoirs.

Abstract: There is provided herein a system and method of acquiring, processing, and imaging transient Controlled Source ElectroMagnetic (t-CSEM) data in ways that are similar to those used for seismic data. In particular, the instant invention exploits the time-distance characteristics of t-CSEM data to permit the design and execution of t-CSEM surveys for optimal subsequent processing and imaging. The instant invention illustrates how to correct t-CSEM data traces for attenuation and dispersion, so that their characteristics are more like those of seismic data and can be processed using algorithms familiar to the seismic processor. The resulting t-CSEM images, particularly if combined with corresponding seismic images, may be used to infer the location of hydrocarbon reservoirs.

Abstract: There is provided herein a system and method of collecting, EM data in the context(s) of hydrocarbon exploration, appraisal, development, and surveillance, which provides improved ground coupling between the electrodes and the earth or surface ice and, as a consequence, a higher quality transmitted and received signal is obtained thereby. Where the surface of the ground is saturated and frozen (e.g., in the case of a survey conducted on sea ice or frozen tundra), the survey instruments (sources and receivers) may be coupled more faithfully to the surface by drilling or melting holes into the ice (or frozen tundra) and inserting electrodes into the resulting holes. Each hole may (or may not) be lined with material to retard the loss of water therefrom. Preferably, each of the holes (source and receiver) will be filled with water (fresh or salt) before data collection begins.

Abstract: A method for determining spatial distribution of properties of the Earth's subsurface includes obtaining seismic data over a survey area of the Earth's subsurface. Controlled source electromagnetic survey data are obtained over substantially the same survey area. An initial model of the Earth's subsurface for each of the seismic data and the electromagnetic data is generated. Further data may include gravity, magnetics, seismics any type and borehole data. Each model is optimized on at least one model parameter. Consistency is determined between the models; and the at least one model parameter is adjusted and the optimizing and determining consistency are repeated until the models are consistent. Constraints are successively derived from the data sets and also cross checked against reservoir data where available.

Abstract: There is provided herein a system and method of collecting, EM data in the context(s) of hydrocarbon exploration, appraisal, development, and surveillance, which provides improved ground coupling between the electrodes and the earth or surface ice and, as a consequence, a higher quality transmitted and received signal is obtained thereby. Where the surface of the ground is saturated and frozen (e.g., in the case of a survey conducted on sea ice or frozen tundra), the survey instruments (sources and receivers) may be coupled more faithfully to the surface by drilling or melting holes into the ice (or frozen tundra) and inserting electrodes into the resulting holes. Each hole may (or may not) be lined with material to retard the loss of water therefrom. Preferably, each of the holes (source and receiver) will be filled with water (fresh or salt) before data collection begins.

Abstract: A method for determining spatial distribution of properties of the Earth's subsurface includes obtaining seismic data over a survey area of the Earth's subsurface. Controlled source electromagnetic survey data are obtained over substantially the same survey area. An initial model of the Earth's subsurface for each of the seismic data and the electromagnetic data is generated. Further data may include gravity, magnetics, seismics any type and borehole data. Each model is optimized on at least one model parameter. Consistency is determined between the models; and the at least one model parameter is adjusted and the optimizing and determining consistency are repeated until the models are consistent. Constraints are successively derived from the data sets and also cross checked against reservoir data where available.

Abstract: A method for controlled source electromagnetic Earth surveying includes deploying a plurality of electromagnetic sensors in a selected pattern at the top of an area of the Earth's subsurface to be surveyed. At least one of a transient electric field and a transient magnetic field is applied to the Earth in the vicinity of the sensors at a plurality of different positions. At least one of electric field amplitude and magnetic field amplitude at each of the sensors is recorded each time the transient electric field and/or magnetic field is applied. Each recording is adjusted for acquisition geometry. An image is generated corresponding to at least one sensor position using at least two stacked, adjusted recordings.

Abstract: There is provided herein a system and method of acquiring, processing, and imaging transient Controlled Source ElectroMagnetic (t-CSEM) data in ways that are similar to those used for seismic data. In particular, the instant invention exploits the time-distance characteristics of t-CSEM data to permit the design and execution of t-CSEM surveys for optimal subsequent processing and imaging. The instant invention illustrates how to correct t-CSEM data traces for attenuation and dispersion, so that their characteristics are more like those of seismic data and can be processed using algorithms familiar to the seismic processor. The resulting t-CSEM images, particularly if combined with corresponding seismic images, may be used to infer the location of hydrocarbon reservoirs.

Abstract: A method for identifying features in the Earth's subsurface below a body of water using transient controlled source electromagnetic measurements includes acquiring a plurality of transient controlled source electromagnetic measurements. Each measurement represents a different value of an acquisition parameter. Each measurement is indexed with respect to a time at which an electric measuring current source is switched. The plurality of measurements is processed in a seismic trace display format, in which each trace corresponds to the measurement acquired for a value of the acquisition parameter. A subsurface feature is identified from the processed measurements.

Abstract: A method and apparatus for high-resolution measurement of seismic anisotropy, comprising: a recording system, a borehole having an axis that is deviated from the vertical by a known acute angle; a housing that is adapted to travel within the borehole and that is in electronic communication to the recording system, the housing carrying at least one source of acoustic energy and at least two receivers for receiving acoustic energy from geological formation elements and/or lithologic horizons and from the source; and processing means for operating the source and the receivers, for recording the position of the housing in the borehole and for processing data from said recording system in terms of both the direct raypaths from the source to the receivers and the indirect raypaths from the source through geological formation elements and/or lithologic horizons to the receivers to obtain measures of at least the seismic polar anisotropy parameters V0, ?, and ?.

Abstract: The instant invention pertains generally to a method of seismic processing of multi-component converted wave 2-D and 3-D seismic data, wherein the seismic traces in each CCP gather may have been acquired at a variety of different source-receiver azimuths. According to one aspect of the instant invention there is provided a method of using recorded multi-component seismic data to determine an estimate of the orientation of the two principle coordinate axes of a subsurface medium, with this determination potentially being made in each seismic survey bin, and for each depth. Given this estimate, the seismic data may then be transformed via rotation into the coordinate system so defined, and thereafter processed using conventional algorithms (e.g., to produce velocity functions and images).

Abstract: The instant invention is generally directed toward methods of using an AVO-type analysis on unstacked seismic data to identify subsurface exploration prospects. More particularly, a new method of identiflying and displaying converted mode seismic reflections is provided that has significant advantages over that in the prior art. Additionally, the instant invention can be used to attenuate or eliminate seismic reflections such as multiples that are not flattened by conventional velocity analysis. Further, a method is disclosed that provides for identification and display of only those seismic reflections deemed consistent with the usual or expected AVO behavior. Finally, another aspect of the instant invention involves the use of statistical goodness of fit measures, such as the Coefficient of Determination, to create a seismic display that is indicative of the degree to which each time slice in a gather conforms to a proposed AVO model.

Abstract: The instant invention provides a method for processing converted-wave data into interpretable images using a compact two-parameter model. The method broadly comprises the steps of: collecting both P-wave and converted-wave seismic data; identifying the arrival times of the P-wave and the converted-wave data; computing the vertical velocity ratio from the arrival time data; computing the moveout velocity ratio from the corresponding moveout velocities; computing the effective velocity ratio from the vertical velocity ratio and the moveout velocity ratio; and computing the conversion point from the short-spread P-wave moveout velocity for each reflector, from the effective velocity ratio, the C-wave moveout velocity ratio, and from the arrival time data.