A method for surveying, may include receiving, by a processor, first survey data from a first source, the first source comprising a first signal generated by a subsurface earth formation in response to a passive-source electromagnetic signal, wherein the electromagnetic signal is generated by an electroseismic or seismoelectric conversion of the passive-source electromagnetic signal. The method may also include receiving, by the processor, second survey data from a second source and processing the first survey data and the second survey data to determine one or more properties of a subsurface earth formation.

A surface wave prospecting method for jointly extracting Rayleigh wave frequency dispersion characteristics in a seismoelectric field. A surface wave prospecting method includes following steps of: acquiring jointly acquired data, where the jointly acquired data includes seismic wave data and electric field data; carrying out jointly imaging processing on jointly acquired data to obtain a superposed frequency dispersion spectrum; carrying out extraction processing on superposed frequency dispersion spectrum to obtain a frequency dispersion curve, outperforming inversion processing on frequency dispersion curve to obtain a stratum structure profile. As seismic wave data and electric field data are adopted to carry out combined imaging processing to obtain superposed frequency dispersion spectrum, multi-mode frequency dispersion curve is extracted, multiplicity of solutions of inversion is greatly reduced during inversion, precision and stability of surface wave prospecting are greatly improved.

The present invention relates to acoustic wavefields produced using sources appropriately delayed in time and focused at known positions and times in a heterogeneous medium. Seismoelectric conversion occurs if the acoustic focus point coincides with a discontinuity in electrical and hydrological medium properties, thus generating a current density. The current generates a potential difference, which can be observed at a distance by an array of monitoring electrodes. Since the acoustic wavefield is precisely located at a position and time, this electrical source behaves like a controlled virtual electrode whose properties depend on the strength of the acoustic wavefield and on the medium properties. This procedure can be used to increase the robustness and resolutions of electrical resistivity tomography and to identify hydrological parameters at various points in the medium by scanning the medium by changing the position of the acoustic focus.

Apparatus having a focused transducer and methods of operating a focused transducer downhole in a well can provide high resolution downhole imaging. In various embodiments, a focused transducer is used for imaging downhole in a well in which the imaging is based on a seismoelectric effect. In various embodiments, a focused transducer is used for imaging downhole in a well in which the imaging is based on an electroacoustic effect. Additional apparatus, systems, and methods are disclosed.

Systems and methods are provided for a magneto-seismic exploration of a subsurface region. An electromagnetic source may transmit time-varying electromagnetic field into the subsurface region, in the presence of a static or time-varying magnetic field, such that a component of the electric field associated with the time-varying electromagnetic field is substantially parallel to an interface between two subsurface formations in the subsurface region, wherein the electric field interacts with the static or time-varying magnetic field and creates a Lorentz force in each of the subsurface formations. One or more seismic receivers may detect a seismic signal generated by a Lorentz force change at the interface between the two subsurface formations. A computer system may be programmed to process and present the detected seismic signal.

A method for surveying, may include receiving, by a processor, first survey data from a first source, the first source comprising a first signal generated by a subsurface earth formation in response to a passive-source electromagnetic signal, wherein the electromagnetic signal is generated by an electroseismic or seismoelectric conversion of the passive-source electromagnetic signal. The method may also include receiving, by the processor, second survey data from a second source and processing the first survey data and the second survey data to determine one or more properties of a subsurface earth formation.

A method for fluid identification and saturation estimation in subsurface rock formations using the Controlled Source Electromagnetic (CSEM) data and Seismic Data by calculating the fluid saturation (S.sub.fl) in a reservoir given the resistivity obtained from CSEM data, and acoustic impedance obtained from the seismic data, comprising the following steps: a) obtaining wireline data within a zone of interest in a nearby well and determining the resistivity of water by calibrating the background resistivity trend with a reference S.sub.fl curve, b) obtaining inverted CSEM survey data from a subsurface zone of interest, c) obtaining inverted seismic data in the form of Acoustic Impedance (AI), d) bringing both the inverted CSEM and acoustic impedance data to a same domain; time or depth, f) calculating fluid saturation using a rock physics model inputting the resistivity of water along with inverted CSEM and acoustic impedance data, resulting in a S.sub.fl profile.

A surface wave prospecting method for jointly extracting Rayleigh wave frequency dispersion characteristics in a seismoelectric field. A surface wave prospecting method includes following steps of: acquiring jointly acquired data, where the jointly acquired data includes seismic wave data and electric field data; carrying out jointly imaging processing on jointly acquired data to obtain a superposed frequency dispersion spectrum; carrying out extraction processing on superposed frequency dispersion spectrum to obtain a frequency dispersion curve, outperforming inversion processing on frequency dispersion curve to obtain a stratum structure profile. As seismic wave data and electric field data are adopted to carry out combined imaging processing to obtain superposed frequency dispersion spectrum, multi-mode frequency dispersion curve is extracted, multiplicity of solutions of inversion is greatly reduced during inversion, precision and stability of surface wave prospecting are greatly improved.

A mobile platform for assessing and modifying pavement surfaces. An emitter generates electromagnetic waves towards a portion of a pavement surface. A condition sensor receives electromagnetic radiation from a first portion of the pavement surface and generates a first electronic signal representative of a current condition of the portion of the pavement surface. A location sensor generates a second electronic signal containing location data corresponding to the first portion of the pavement surface. A computing platform processes the electronic signals and creates a current pavement condition data point. The computing platform may compare the first electronic signal against a reference representative of a target condition, determine if there is a condition variance, and, if a condition variance exceeds a predetermined threshold, generate a condition control signal which is transmitted to and operates to modify operation of the pavement surface modification system in order to reduce the condition variance.

A disclosed downhole drilling system may include a drill bit electrically coupled to a pulse-generating circuit to generate electrical arcs between first and second electrodes during pulsed drilling operations, a sensor to record responses to electromagnetic or acoustic waves produced by the electrical arcs, and a sensor analysis system. The electrical arcs occur at different azimuthal locations between the electrodes. The sensor analysis system may obtain a plurality of measurements representing first responses recorded by the sensor during a pulsed drilling operation, generate a model of a source of the electrical arcs based on the measurements, obtain an additional measurement representing a second response recorded by the sensor during the operation, and determine a characteristic of a formation near the drill bit using an inversion based on the model and the additional measurement. The determined characteristic may be used to determine dip parameters or construct images of the formation.