Abstract: A system and method for use in environment with electrical equipment is provided. The system including a housing and at least one light source located on an exterior of the housing. The light source being activated when the system is in a switching mode of operation. At least one sensor is operably coupled to the housing and configured to measure at least one parameter associated with the electrical equipment. A computing device is disposed within the housing and coupled to communicate with the at least one light source and the at least one sensor.

Abstract: A power supply unit for an aerosol inhaler includes: a power supply configured to supply power to a load that atomizes an aerosol source; a temperature sensor configured to acquire a temperature of the power supply; a controller; and a circuit board on which a plurality of elements including the temperature sensor and the controller are mounted. The circuit board includes a first surface and a second surface which is a reverse surface from the first surface or is located on a side opposite from the first surface. The plurality of elements are mounted on each of the first surface and the second surface. The second surface faces the power supply, and/or the second surface is arranged closer to the power supply than the first surface. The temperature sensor is mounted on the second surface.

Abstract: A three-axis spacecraft including a spacecraft body including first and second opposing radiator/equipment panels, first and second opposing mounting panels, an earth deck and a zenith deck. The zenith deck faces the Earth when the spacecraft is on orbit and the first and second mounting panels face an east and west direction relative to the Earth when the spacecraft is on orbit. The spacecraft further includes a mounting cylinder extending through the spacecraft body and out of the first and second mounting panels.

Abstract: The disclosure pertains to the field of electromagnetic exploration, and in particular relates to a device and method for ground source transient electromagnetic near-field detection and related device, with the purpose of solving the problems that the method for loop source transient electromagnetic detection has a relatively small detection depth and weak signals. The device of the disclosure includes an excitation source emitting device and a receiving device for signal detection. The excitation source emitting device includes an emission source, the emission source is a grounded conductor wire; the grounded conductor wire is used to convert a bipolar pulsed current into an electromagnetic field to be emitted underground; and the receiving device is configured for detecting a magnetic field and/or electric field signal in a survey line segment of an observation range of the grounded conductor wire using the method of areal sideline scanning survey.

Abstract: In-situ calibration of a resistivity logging tool is accomplished using a variety of methods in which deep measurement signals are calibrated using acquired and simulated measurement signals.

Abstract: An electromagnetic geophysical survey is performed by transmitting current from a first source into earth, the first source being located in a borehole. An electromagnetic field generated by the current transmitted from the first source is measured to create subsurface data. In addition, a background model is constructed and a leakage current distribution is calculated. A resistivity distribution of the earth is calculated using the subsurface data, the background model and the leakage current distribution, with the leakage current distribution being used as a source current distribution.

Abstract: A stabilized course sand bunker and method of making the same is disclosed. The soil making up the bunker is contoured and stabilized so that it is in the form of a pit having a downward angularly extending keyway surrounding the opening at the top edge of the pit. A semi-solid precursor material is applied over the pit and keyway and allowed to cure to form a barrier liner having a flanged anchoring portion for location under some additional soil and turf grass. Bunker sand is disposed over the barrier liner. The barrier liner when cured enables water in the bunker to pass through it, is sufficient flexible to dampen and absorb the impact of a golf ball strike, all the while stabilizing and protecting the edge of the bunker where the turf grass meets the sand in the bunker.

Abstract: Techniques related to making resistivity measurements of an underground formation surrounding a borehole involve using a tool having a pad mounted on the body of the tool. The pad has a current injector electrode and a current return electrode mounted on the pad face and arranged such that the current injector and return electrodes are electrically isolated from each other when in use. Two impedance ratios are determined. The first is a ratio of the electrical impedance between the current injector electrode and the tool body, and the electrical impedance between the current return electrode and the tool body. The second is a ratio of the electrical impedance between the current injector electrode and the formation, and the electrical impedance between the current return electrode and the formation. The tool is arranged such that the two impedance ratios differ by 25% or less of the larger impedance ratio.

Abstract: A circuit for simulating an electrical load at a terminal of a test circuit having at least one first switch and at least one second switch includes a third switch connected to the first switch of the test circuit via a first external connection point. A fourth switch is connected to the second switch of the test circuit via a second external connection point. The first switch and the second switch are connected via a shared, first internal connection point to the terminal of the test circuit and the third switch and the fourth switch are connected via a shared, second internal connection point such that that the first switch, the second switch, the third switch and the fourth switch form an H-bridge circuit. A voltage source is configured to provide the first and second external connection points with a supply voltage. A controllable voltage source is connected in a transverse bridge branch between the terminal and the second internal connection point. An inductance is active in the transverse bridge branch.

Abstract: A current detecting device includes a second fixed part to which the harness is fixed and electrically connected, a bus bar as a resistor inserted between a first fixed part and the second fixed part, a circuit board in which a current detection circuit is mounted, the current detection circuit detecting current flowing through the bus bar based on a potential difference between two points along an energizing direction of the bus bar, and a case accommodating the bus bar and the circuit board. The second fixed part to which the harness is fixed and electrically connected is disposed within a battery upper surface area.

Abstract: A method of monitoring an extent of a hydrocarbon reservoir (2) below the earth's surface (4), includes the steps of applying a current between a bottom current electrode (6) and a top current electrode (8) that is part of a plurality of electrodes that are spaced apart from one another along a part of the earth's surface located above and optionally over the hydrocarbon reservoir. The bottom current electrode is positioned below the hydrocarbon reservoir. The method includes the step of measuring an electrical potential, which is caused by the current, by means of a measurement electrode (10A) that is also part of the plurality of electrodes. The method includes the step of inferring from the measured electrical potential the extent of the hydrocarbon reservoir, in a direction that is oriented substantially parallel with the earth's surface.

Abstract: A marine electromagnetic receiver cable includes a plurality of signal processing modules disposed at spaced apart locations along the receiver cable. A power supply line is connected to each of the signal processing modules and to an electric current source. A current regulation device is connected in the power supply line proximate each signal processing module. The current regulation devices are connected such that an amount of current flowing through the power supply line is substantially constant. At least one electromagnetic receiver is functionally coupled to an input of each signal processing module.

Abstract: A method and apparatus of constructing a signal for a controlled source electromagnetic survey is described. In one embodiment, a method is described that includes determining a first waveform and a second waveform, the first waveform and second waveform related to a combined frequency spectrum and bandwidth associated with a geophysical survey line. Then, a signal is constructed by sequencing the first waveform with the second waveform. This signal may be utilized in a transmitter, which may be pulled by a vessel along the geophysical survey line.

Abstract: A testing device which may be used to conduct ground resistance and soil resistivity measurements. The testing device comprises both a main unit and a remote unit adapted to communicate with one another via a communication link. After setting the testing device up according to the desired measurement technique, the procedure may be carried out, and the resulting measurement values are subsequently displayed on the remote unit. This allows a single operator to perform measurements while standing directly adjacent to an electrode, which is, for example, placed at a large distance from the main unit and/or other electrodes. This relieves the operator from constantly having to walk back and forth placing electrodes in different positions, and also obviates the need to return to the main unit of the testing device to consult a display and/or change parameters or settings.

Abstract: A system for measuring a resistivity parameter of an earth formation includes: at least one measurement electrode electrically connected to a first electrical source; at least one guard electrode; a shielding electrode interposed between the at least one guard electrode and the at least one measurement electrode, the shielding electrode being electrically connected to a second electrical source independent from the first electrical source, and the guard electrode being electrically connected to a third electrical source independent of the first and second electrical sources; at least one return electrode; insulators positioned between (i) the measurement electrode and the shielding electrode, (ii) the shielding electrode and the guard electrode and (iii) the measurement electrode, the guard electrode and the return electrode; and a processor configured to adjust at least one of the first electrical source and the second electrical source to minimize a current flow through the shielding electrode.

Abstract: A method used in electrical investigation of geological formations surrounding a borehole comprising: determining S1 a grid of iso-parameter lines GR in a two-dimensional plane, the parameter being an electrical parameter characterizing the geological formation, injecting in a localized manner a survey current IS into a selected zone SZ of the geological formations GF surrounding the borehole BH, and measuring S2 a measured value of a quantity characterizing the electrical parameter of the selected zone based on the survey current, and interpolating S3 an interpolated electrical parameter value of the selected zone SZ based on the measured value and the grid of iso-parameter lines GR.

Abstract: A method for measuring resistivity variations in the earth comprising passing a transient current between two source electrodes; measuring the transient current at the source electrodes; measuring the resultant transient voltage between at least one pair of receiver electrodes; estimating one or more processing functions for applying to the measured input current to provide a step current profile, and applying the same one or more processing functions to the measured voltage to provide an estimate of the step response voltage between the receivers, using both the step current and the estimated step response voltage to determine the resulting apparent earth resistance, and using the apparent earth resistance to determine the resistivity of the earth.

Abstract: A system for measuring geological data is disclosed. The system includes several transceivers distributed over a geographical area. Each of the transceivers has at least one transmitter and at least one receiver. The transceivers are in communication with each other. The receivers are adapted to measure at least one electrical signal. The transmitters are adapted to inject an electrical current into a subsurface area.

Abstract: A device and method for measuring electromagnetic signals that can be used to take measurements at or near the sea floor. The device comprises a central housing, a data management system located within the housing and at least two arms extending outwards from the housing. Each arm comprises a flexible elongate sheath attached to the housing, a sensor head, a flexible electrical cable attached to the sheath and connecting the sensor head to the data management system and a rod which is removeably locatable within the sheath. The rod is connectable relative to the housing at one end and connectable relative to the sensor head at the end remote from the housing.

Abstract: To perform surveying of a subterranean structure, an electromagnetic (EM) source array has a plurality of electrodes. Different subsets of the electrodes are dynamically activated to provide corresponding EM radiation patterns to survey the subterranean structure.

Abstract: A device, method and system for measuring characteristics of a geologic formation using a floating reference signal having a mud chamber, an electrode disposed within the mud chamber, and an electrically conductive plate disposed within the mud chamber, the plate separated from the electrode. An alternating current source is provided on the electrode, whereby an electric field is be maintained between the electrode and the conductive plate. An opening in the mud chamber allows drilling fluids to pass there through.

Abstract: To perform marine electromagnetic (EM) surveying of a subterranean structure, a marine cable system is provided including a tow cable, a plurality of electromagnetic (EM) sources coupled to the tow cable, and a plurality of EM receivers coupled to the tow cable. The system is configured for deployment in a body of water to perform marine EM surveying of a subterranean structure.

Abstract: Methods and apparatus for determining a presence of a non-conductive coating on electrodes in fluid resistivity measurement devices are described. An example method of determining a presence of a non-conductive coating on electrodes of a fluid resistivity measurement device involves obtaining a first electrical potential value associated with a substantially uncoated condition of first and second electrodes of a fluid resistivity measurement device. The example method also involves measuring a second electrical potential value at a location between the first and second electrodes, comparing the first and second electrical potential values, and determining the presence of a non-conductive coating on at least one of the first and second electrodes based on the comparison.

Abstract: A method and apparatus of constructing a signal for a controlled source electromagnetic survey is described. In one embodiment, a method is described that includes determining a first waveform and a second waveform, the first waveform and second waveform related to a combined frequency spectrum and bandwidth associated with a geophysical survey line. Then, a signal is constructed by sequencing the first waveform with the second waveform. This signal may be utilized in a transmitter, which may be pulled by a vessel along the geophysical survey line.

Abstract: A method and apparatus for measuring the resistivity anisotropy of cylindrical rock samples is disclosed. The measurement setup includes two pairs of electrodes that contact the sample surface. The ring electrodes of the first pair are disposed on the cylindrical surface of the sample. The cap electrodes of the second pair are mounted at the sample ends. Two differences in potentials are measured. One of the cap electrodes and the nearest ring electrode are used to measure the first difference that results from current injected through the remaining cap and ring electrodes. The second difference is measured between the two ring electrodes, while current is injected through the first and second end cap electrodes. These two differences are inverted for the anisotropy coefficient, horizontal and vertical resistivity.

Abstract: A method for measuring resistivity variations in the earth comprising passing a transient current between two source electrodes; measuring the transient current at the source electrodes; measuring the resultant transient voltage between at least one pair of receiver electrodes; estimating one or more processing functions for applying to the measured input current to provide a step current profile, and applying the same one or more processing functions to the measured voltage to provide an estimate of the step response voltage between the receivers, using both the step current and the estimated step response voltage between voltage to determine the resulting apparent earth resistance, and using the apparent earth resistance to determine the resistivity of the earth.

Abstract: Method for removing air wave noise from shallow water controlled source electromagnetic survey data, using only the measured data and conductivity values for sea water (140) and air. The method is a calculation performed numerically on CSEM data and resulting in an estimate of those data that would have been acquired had the water layer extended infinitely upward from the seafloor. No properties of the sub-sea sediments are used. Synthetic electromagnetic field data are generated for (a) an all water model (141) and (b) an air-water model (146-147) of the survey region. These simulated results are then used to calculate (148-150) electromagnetic field values corresponding to a water-sediment model with water replacing the air half space, which represent measured data adjusted to remove air wave noise.

Abstract: An apparatus for automatic control of current electrodes in a measuring system for an electrical resistivity survey includes: a circuit where one pair of metal oxide semiconductor field effect transistors (MOSFETs) are connected to upper and lower terminals of n current electrodes and the one pair of MOSFETs are connected in parallel with each other; and a controller which controls ON/OFF of each MOSFET.

Abstract: A process and device for measurement of spectral induced polarization response of subsurface over a wide band of frequencies (0.03 Hz to 100 Hz) using pseudo noise current source, is provided. (Pseudo Random Binary Sequence current source). The measurement setup employs a current source (500 VA) and a computer controlled real time correlator for excitation of the subsurface. The current from the source is reversed through the grounded electrodes in a Pseudo Random Binary Sequence (PRBS) and the computer based receiver essentially computes Auto (input-input) and Cross (input-output) correlation estimates in the field. The collected data (time series) is transformed into frequency domain (DFT) in order to obtain the phase spectrum. The receiver has a provision to stack data for an improved S/N ratio. Measurements taken in laboratory using simple RC network, which simulates the subsurface, are accurate. Accuracy of measurement is better than 2% in Band-I (0.031-2 Hz) and 1% in Band-II (2-100 Hz) respectively.

Abstract: Multiple sources are provided for a transmitter cable for use in electromagnetic surveying. The transmitter cable includes a dipole antenna comprising a pair of spaced apart electrodes mounted on their respective cables. Two antennas may be powered from each source. Alternatively, the outputs of each source are connected to a common antenna pair. A single large power supply may be mounted on a vessel to supply power through the tow cable. Alternatively, a number of power supplies may be provided aboard the vessel, with each power supply having dedicated conductors through the tow cable to power the plurality of current sources.

Abstract: A method and system for measuring formation resisitivity is achieved by introducing an electrical signal into the formation. The current of the introduced electrical signal is then sensed, producing an analog voltage signal as a measurement of the formation. The introduced electrical signal is compared with the measured signal of the formation. The comparison is made in a quadrature demodulation device, producing an in-phase demodulated signal. A quasi-direct-current signal is extracted from the in-phase demodulated signal, producing an analog measurement related to the resistivity of the formation.

Abstract: The invention a method and device for carrying out geoelectric mappings. The device includes electrodes, a power supply and a voltage measuring device, for carrying out the method. The electrodes are disposed apart from one another on ground to be investigated and electric current is supplied by certain electrodes to the ground and electric potential is measured by remaining electrodes using the voltage measuring device. The device and method carry out a continuous, geoelectric mapping, with which accurate measurements are achieved. The device is embodied such that the electrodes are disposed at a outside of an endless loop and that this endless loop revolves continuously at the same rate at which the device is moving over the ground to be investigated during the mapping, so that at least two supplying and two potential electrodes rest on the ground investigated during each individual measurement.

Abstract: Logging-while-drilling apparatus and methodologies for measuring streaming potential in an earth formation are provided. The apparatus and methodologies can be utilized to find information relevant to the drilling operations. In particular, since the streaming potential measurement relates directly to fluid flow, the streaming potential measurements can be used to track flow of fluids in the formation. In turn, this information may be used to find information relevant to the drilling operations, such as under-balanced drilling conditions, abnormal formation pressures, open fractures, the permeability of the formation, and formation pressure.

Abstract: Methods and apparatus are provided for receiving, detecting and transmitting geophysical data from a plurality of electrodes placed in the soil utilizing a dynamically reconfigurable wireless control unit that is located on each electrode. Data from the control units is transmitted by a wireless signal to a centralized data processor for analysis. Control data is provided from a central control processor to the control unit by wireless transmission. The control unit, which is positioned, includes a multi-channel radio frequency transmitter/receiver and a processor to actuate relays and record data returns from the measured substrate soil for transmission to the central data processor. The control unit incorporates a changeable code or address to unambiguously identify itself, and its spatial relationship to other electrodes, to the central data processor and the central control processor.

Abstract: Multiple sources are provided for a transmitter cable for use in electromagnetic surveying. The transmitter cable includes a dipole antenna comprising a pair of spaced apart electrodes mounted on their respective cables. Two antennas may be powered from each source. Alternatively, the outputs of each source are connected to a common antenna pair. A single large power supply may be mounted on a vessel to supply power through the tow cable. Alternatively, a number of power supplies may be provided aboard the vessel, with each power supply having dedicated conductors through the tow cable to power the plurality of current sources.

Abstract: A method for measuring a resistivity of a subsurface formation that includes transmitting continuously a signal at a first fundamental frequency at full power for a first period of time within a single window of time causing electromagnetic energy to propagate in the subsurface formations, transmitting continuously the signal at a second fundamental frequency at full power for a second period of time within the single window of time causing electromagnetic energy to propagate in the subsurface formations, measuring variations in the electromagnetic energy propagated through the subsurface formations at receivers at the first and the second fundamental frequencies, and determining the resistivity of the subsurface formations using the measurements of the variations in electromagnetic energy at the receivers.

Abstract: A pair of pads is formed on an insulating layer formed on a top surface of a substrate, and a plurality of through-holes is laid out at equal intervals between the pads. Adjoining through holes are connected alternately by upper-layer wire interconnect lines exposed on the insulating layer or lower-layer wire interconnect lines buried in the insulating layer, thus constituting a check pattern. A DC power supply is connected between the pair of pads, and a constant current is supplied to a chain pattern of the through holes. Two probes move on a chip surface along the chain pattern of the through holes while keeping a given interval spacing. The probes sequentially scan the upper-layer wire interconnect lines exposed through the chip surface of the chain pattern of the through-holes.

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: An overcurrent detecting device for detecting an overcurrent in a load circuit, includes a DC power supply, a load, a semiconductor switch that controls ON/OFF of the load, a driver circuit that outputs a driving signal to the semiconductor switch, a reference voltage generating circuit that generates a reference voltage from the DC power supply, a voltage drop generating circuit that includes a resistor for generating a voltage drop and generates a voltage drop in the resistor for generating a voltage drop, a decision voltage generating circuit that generates, as a decision voltage, a voltage corresponding to a voltage obtained by adding a voltage drop generated when the semiconductor switch is turned ON and a voltage drop generated in the resistor for generating a voltage drop, and a comparing circuit that compares the decision voltage with the reference voltage and outputs a disconnecting command signal of the semiconductor switch to the driver circuit when the decision voltage is greater than the referenc

Abstract: A method and apparatus for minimizing direct coupling between transmitters and receivers on a downhole logging tool are disclosed. One embodiment includes a transmitter, a bucking device, and a plurality of receivers, where signals may be directly coupled from the transmitter into the receivers and signals may be indirectly coupled from the transmitter into the receivers through the formation and borehole environment. The bucking device minimizes the magnitude of the signals that are directly coupled from the transmitter into multiple receivers within the plurality. By varying the current in the bucking device, the bucking device minimizes the magnitude of the directly coupled signal of each receiver in the plurality, and each receiver may utilize a common bucking device.

Abstract: The invention relates to a device for assisting in the measurement of the earth resistance comprising a ground rod with a wire coiled up on a reel or the like, and electrical connecting means for connecting the wire to the ground rod. To provide such a device which is practical to handle, simple, small, and capable of being produced at low costs, it is provided for the reel or the like to be rotatably mounted on the ground rod. A further improvement results in that the ground rod comprises an offset portion in whose region the reel or the like is rotatably mounted. Preferably, the electrical connecting means between ground rod and wire comprise sliding rings on the rotation axis, the reel or the like. For an rapid exchangeability of the reel, the latter may be mounted on the ground rod by a snap connection.

Abstract: A method for seismic exploration using nonlinear conversions between electromagnetic and seismic energy, with particular attention to the electromagnetic source waveform used. According to the invention, seismic returns from a source waveform are correlated with a reference waveform, with both waveforms custom designed to minimize both correlation side lobes and interference from linear electroseismic effects. A waveform element is selected which may be sequenced by a binary or similar digital code embodying the desired custom design to generate an input sweep with the needed depth penetration and noise suppression. Correlation of the seismic response with the reference waveform in a data processing step mathematically aggregates the seismic response from the input sweep into a single wavelet. Preferred binary digital codes include prescribed variations of maximal length shift-register sequences. Also, an apparatus for generating the desired waveforms.

Abstract: A method for surface estimation of reservoir properties, wherein location of and average earth resistivities above, below, and horizontally adjacent to the subsurface geologic formation are first determined using geological and geophysical data in the vicinity of the subsurface geologic formation. Then dimensions and probing frequency for an electromagnetic source are determined to substantially maximize transmitted vertical and horizontal electric currents at the subsurface geologic formation, using the location and the average earth resistivities. Next, the electromagnetic source is activated at or near surface, approximately centered above the subsurface geologic formation and a plurality of components of electromagnetic response is measured with a receiver array. Geometrical and electrical parameter constraints are determined, using the geological and geophysical data.

Abstract: A method and apparatus for measuring in-place soil density and moisture content. A cylindrical cell is disclosed which may be used to measure the density and the dielectric constant of a soil sample placed within the cylindrical cell. Also disclosed is a multiple rod probe which is designed to contact spikes driven into the ground to measure the in-place dielectric constant of soil. The multiple rod probe includes adjustable studs which ensure complete contact with the spikes. Both measurements are performed using time domain reflectometry. The present invention develops equations for determining the density of the soil in-place from the measured dielectric constant of the soil in-place and the measured density and dielectric constant of the soil in the cylindrical cell.

Abstract: A method for monitoring an area of the surface of the earth uses measurement probes arranged in a grid for determining the self-potential with respect to a base probe. The measurement probes are interrogated repeatedly. The earth resistance between measurement probes and the base probe is also measured repeatedly between measurements of self-potential. Potentials on the surface of an area of the earth can be determined precisely, independently of earth-resistance changes.

Abstract: A method of geophysical analysis includes transmitting an electromagnetic signal into the earth and measuring the resulting transmission of that signal through the earth to a plurality of spaced recording units. The values of the transmitted signal are locally digitized and stored at each recording unit. The stored data from each recording unit is subsequently transmitted through a telemetric link to a central processing or analyzing unit, the stored data being transmitted from one recording unit at a time and in a preselected sequence. The data may be transmitted from each recording unit in a block and stored in the central processing unit. The digitizing and storing of the measured values at each unit is accomplished through a yield point amplifier. Automatic drift correction processing may also be applied to the measured values obtained from each recording unit.

Abstract: The method of measuring local rock inhomogeneities on the wall of a borehole is disclosed. The method of measurement includes the step of generating microelectric fields in a conductive way on an area of the wall of the borehole insulated from the drilling mud by an insulating pad which carries electrodes and excludes direct electrical contact between the electrodes and the conductive borehole liquid. The local current intentities are measured at, at least two, different places perpendicularly to the wall of the borehole and the measured current intensities are compared to each other. Alternatively, a local voltage difference created by current flowing first parallel to the wall of the borehole and then an absolute voltage created by the same current in another section of flow where the current is perpendicular to the wall of the borehole may be measured and the measured voltages compared to each other.

Abstract: A method for surface estimation of reservoir properties, wherein location of and average earth resistivities above, below, and horizontally adjacent to the subsurface geologic formation are first determined using geological and geophysical data in the vicinity of the subsurface geologic formation. Then dimensions and probing frequency for an electromagnetic source are determined to substantially maximize transmitted vertical and horizontal electric currents at the subsurface geologic formation, using the location and the average earth resistivities. Next, the electromagnetic source is activated at or near surface, approximately centered above the subsurface geologic formation and a plurality of components of electromagnetic response is measured with a receiver array. Geometrical and electrical parameter constraints are determined, using the geological and geophysical data.

Abstract: A method for surface estimation of reservoir properties, wherein location of and average earth resistivities above, below, and horizontally adjacent to the subsurface geologic formation are first determined using geological and geophysical data in the vicinity of the subsurface geologic formation. Then dimensions and probing frequency for an electromagnetic source are determined to substantially maximize transmitted vertical and horizontal electric currents at the subsurface geologic formation, using the location and the average earth resistivities. Next, the electromagnetic source is activated at or near surface, approximately centered above the subsurface geologic formation and a plurality of components of electromagnetic response is measured with a receiver array. Geometrical and electrical parameter constraints are determined, using the geological and geophysical data.

Abstract: A method for seismic exploration using nonlinear conversions between electromagnetic and seismic energy, with particular attention to the electromagnetic source waveform used. According to the invention, seismic returns from a source waveform are correlated with a reference waveform, with both waveforms custom designed to minimize both correlation side lobes and interference from linear electroseismic effects. A waveform element is selected which may be sequenced by a binary or similar digital code embodying the desired custom design to generate an input sweep with the needed depth penetration and noise suppression. Correlation of the seismic response with the reference waveform in a data processing step mathematically aggregates the seismic response from the input sweep into a single wavelet. Preferred binary digital codes include prescribed variations of maximal length shift-register sequences. Also, an apparatus for generating the desired waveforms.