A circuit having a first, second, and third capacitor. Capacitor plates of the capacitors are connected to a first circuit node. The circuit supplies a first time-dependent voltage to the first capacitor, a second time-dependent voltage to the second capacitor, and a third time-dependent voltage to the third capacitor. The first and second voltages are clocked in antiphase. The second and third voltages are clocked in phase. The circuit has an amplifier, a synchronous demodulator, and a comparator. Inputs of the amplifier are connected to the first circuit node and ground. The synchronous demodulator alternately applies an output signal of the amplifier to inputs of the comparator, synchronously with the clock frequency of the first voltage. The circuit generates a control value dependent on an output of the comparator. The circuit changes amplitudes of the first and third voltage and/or the second voltage dependent on the control value.

A method of imaging electrical conductivity distribution of a subsurface containing metallic structures with known locations and dimensions is disclosed. Current is injected into the subsurface to measure electrical potentials using multiple sets of electrodes, thus generating electrical resistivity tomography measurements. A numeric code is applied to simulate the measured potentials in the presence of the metallic structures. An inversion code is applied that utilizes the electrical resistivity tomography measurements and the simulated measured potentials to image the subsurface electrical conductivity distribution and remove effects of the subsurface metallic structures with known locations and dimensions.

A method of imaging electrical conductivity distribution of a subsurface containing metallic structures with known locations and dimensions is disclosed. Current is injected into the subsurface to measure electrical potentials using multiple sets of electrodes, thus generating electrical resistivity tomography measurements. A numeric code is applied to simulate the measured potentials in the presence of the metallic structures. An inversion code is applied that utilizes the electrical resistivity tomography measurements and the simulated measured potentials to image the subsurface electrical conductivity distribution and remove effects of the subsurface metallic structures with known locations and dimensions.

A system and method for geophysical data collection, for use with resistivity and induced polarization. The system and method include the use of a single voltage reference wire to which all voltage recorders or nodes are connected by means of a piercing wire connector, the voltage recorders providing a measurement of the potential voltage between the reference wire and the ground and allowing for calculation of relative voltage potentials between adjacent recorders.

A system and method for geophysical data collection, for use with resistivity and induced polarization. The system and method include the use of a single voltage reference wire to which all voltage recorders or nodes are connected by means of a piercing wire connector, the voltage recorders providing a measurement of the potential voltage between the reference wire and the ground and allowing for calculation of relative voltage potentials between adjacent recorders.

A method may include obtaining core image data regarding a geological region of interest. The method may further include obtaining well log data regarding the geological region of interest from one or more wells. The method may further include determining a sliding window that corresponds to a predetermined window size. The method may further include determining various quantitative image attributes using the core image data, the well log data, and the sliding window. The quantitative image attributes may be determined in a continuous manner by moving the sliding window along the core image data. The method may further include generating predicted rock data for the geological region of interest using the quantitative image attributes, a machine-learning algorithm, and a machine-learning model.

A method may include obtaining core image data regarding a geological region of interest. The method may further include obtaining well log data regarding the geological region of interest from one or more wells. The method may further include determining a sliding window that corresponds to a predetermined window size. The method may further include determining various quantitative image attributes using the core image data, the well log data, and the sliding window. The quantitative image attributes may be determined in a continuous manner by moving the sliding window along the core image data. The method may further include generating predicted rock data for the geological region of interest using the quantitative image attributes, a machine-learning algorithm, and a machine-learning model.

An electrical prospecting signal transmission device capable of suppressing electromagnetic coupling interference, including a rectangular wave signal source, an output circuit for supplying power to the ground and a plurality of transmission channels. Each of the plurality of transmission channels includes an isolated driving circuit, a low-pass filter circuit and a power amplification circuit connected sequentially in series. The rectangular wave signal source is configured to generate a rectangular wave or a composite rectangular wave. A signal output terminal of the rectangular wave signal source is connected to an input terminal of the isolated driving circuit, and an output terminal of the power amplification circuit is connected to the output circuit to supply power to the ground.

A wireless-power transmission system (WPTS) includes sensors, antennas, a power amplifier (PA), and integrated circuits (ICs). The antennas, upon receiving an amplified signal for the PA, are configured to radiate energy within a transmission field (TF) of the WPTS. The ICs are configured to receive sensor data indicating presence of an object within a keep-out zone (KOZ). The ICs are configured to classify using the sensor data the object as a sensitive object. While detecting presence of the sensitive object, the ICs are configured to forgo providing an instruction to the PA to amplify the signal. In accordance with a determination that the sensitive object is no longer detected the ICs are configured to determine whether an electronic device is within the TF and in accordance with a determination that the electronic device is within the TF the ICs are configured to instruct the PA to amplify the signal.

A wireless-power transmission system (WPTS) includes sensors, antennas, a power amplifier (PA), and integrated circuits (ICs). The antennas, upon receiving an amplified signal for the PA, are configured to radiate energy within a transmission field (TF) of the WPTS. The ICs are configured to receive sensor data indicating presence of an object within a keep-out zone (KOZ). The ICs are configured to classify using the sensor data the object as a sensitive object. While detecting presence of the sensitive object, the ICs are configured to forgo providing an instruction to the PA to amplify the signal. In accordance with a determination that the sensitive object is no longer detected the ICs are configured to determine whether an electronic device is within the TF and in accordance with a determination that the electronic device is within the TF the ICs are configured to instruct the PA to amplify the signal.