Abstract: A method of land surveying that electronically registers together multi-layer underground and surface images of a surface volume with buried utilities and other infrastructures. Such method further comprises assembling and presenting the combination to a device in the field that visually guides crews in their safe digging of the ground nearby. The orienting, scaling, and registering of a first image layer is to a standardized orientation and scaling on a map of a photograph of a land surface from a zenith point in space above. Then the orienting, scaling, and registering of a second image layer is made to the standardized orientation and scaling on the map. This layer is a result of a ground penetrating radar investigation of buried objects point-by-point in an immediate search area of a corresponding ground surface. Underground buried objects and utilities are thereby located to make safe digging nearby.

Abstract: In order to increase result accuracy the noise effect during vessel motion is reduced, wherefore direct current pulses are excited the parameters of which are set basing on section conductivity and deposit depth, the electric field is measured simultaneously on pairs of receiving electrodes basing on the spatial averaging of potential of double electric layer that is generated on the boundary of electrode and water during the pulses and pauses between them, and geoelectrical parameters are determined.

Abstract: A method of estimating a property of an earth formation penetrated by a borehole includes: disposing into the borehole a sensor having a plurality of return electrodes and at least one transmitter electrode disposed in a concentric arrangement; injecting a first current of a first frequency into the formation by applying an alternating current voltage between first selected ones of the plurality of return electrodes and the at least one transmitter electrode; injecting a second current of a second frequency into the formation by applying an alternating current voltage between second selected ones of the plurality of return electrodes and the at least one transmitter electrode; measuring effective impedance for each of the currents; and estimating the property using the measurements of the effective impedance for each of the currents; wherein the estimating compensates for an influence of standoff distances of the sensor on the measurements.

Abstract: A method of estimating standoff in a borehole through an earth formation, includes: disposing a sensor including a plurality of return electrodes and at least one transmitter electrode disposed in a concentric arrangement into the borehole; injecting current, I, into the formation by applying at least two frequencies of alternating current (AC) voltage between at least two of the electrodes; measuring impedance, Z, for each of the frequencies; and using a predetermined relationship between impedance, Z, and standoff, estimating the standoff. A system and a computer program product are provided.

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: Two embodiments of marine geo-electric probe methods for hydrocarbon deposits survey comprise—excitation of electromagnetic field in a surveyed medium by transmitting two rectangular current pulses therethrough, the first—during forward traveling of a probe device along a profile and the second—during backward traveling thereof,—measuring instant values of the first and second electric potential differences during the time between the pulses, wherein, the equal-zero condition of the electric potential differences along the profile is ensured,—calculating three sets of normalized electrical parameters based on difference values,—solving an inverse problem via a differential equation for the dipole source voltage in an electrochemically polarizable medium using the parameters,—producing data according to said electrical parameters, and—determining conductivity of the medium, induced-polarization factor and decay time constant of the polarization potential difference.

Abstract: Good device PASS/FAIL determination is realized by measuring timings of both signals, i.e., a cross point of differential clock signals CLK and a data signal DATA output from a DUT, and obtaining a relative phase difference between both signals.

Abstract: A current sensing system including a carrier strip, the carrier strip disposed so as to be associated with a current carrying conductor, wherein when an electrical current flows through the conductor, the electrical current flowing through the conductor creates a magnetic field having a magnetic flux, wherein the magnetic flux is responsive to the electrical current flow, a Hall effect sensor disposed relative to the carrier strip such that the Hall effect sensor is communicated with the magnetic field, wherein the Hall effect sensor generates an electrical signal responsive to the magnetic flux and a metering device in communication with the Hall effect sensor, wherein the metering device processes the electrical signal so as to create a processed signal responsive to the electrical current flow.

Abstract: A method and apparatus for collecting measurements on the surface of the earth in a form which can be processed to obtain enhanced resolution of subsurface resistivity anomalies in the earth's geologic structure. The system of the preferred embodiment utilizes many separately acquired voltage and current measurements on the earth's surface in a superposition analysis to "synthesize" the condition whereby the many separate measurements are acquired simultaneously to give useful advantages in improved depth of investigation commonly known as focused resistivity measurements.

Abstract: A geophysical exploration system uses a single conductor cable connected to a current source, the cable having a number of earth probes coupled to it at spaced points with addressable switching units. The switching units are activated in sequence so that the probes inject current into the earth. At locations spaced from the probes the resistivity is measured and recorded for each injection. Resistivity measurements are compared with anomaly models to find a match of patterns, indicating the presence, size and location of an anomaly.

Abstract: A method and apparatus for electromagnetic hydrocarbon exploration which is accomplished by implanting at least two pairs of electrodes into the ground. One pair transmits a signal into the earth, and the other pair receives the signal. With proper processing the polarization and resistivity of the ground can be calculated. The components are arranged in a manner to insure that the electromagnetic coupling can be determined and can be removed from the measurements. Electrode spacing can be varied to focus on the anomalous stratum. If an anomalous stratum is discovered, it is cored to determine the nature of the material creating the anomaly.