| Entries |
| Document | Title | Date |
|---|
| 20090322337 | Analog Front-End Coherent In-Phase Demodulation Data Acquisition System for Resistivity Image Tools - 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. | 12-31-2009 |
| 20100102822 | PROCESS AND DEVICE FOR MEASUREMENT OF SPECTRAL INDUCED POLARIZATION RESPONSE USING PSEUDO RANDOM BINARY SEQUENCE (PRBS) CURRENT SOURCE - 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. | 04-29-2010 |
| 20100315088 | Multi-Transient DC Resistivity Measurements - 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. | 12-16-2010 |
| 20110037474 | METHOD AND SYSTEM FOR MEASURING RESISTIVITY ANISOTROPY OF LAYERED ROCK SAMPLES - 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. | 02-17-2011 |
| 20120146650 | Providing an Electromagnetic Source Array Having a Plurality of Electrodes - 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. | 06-14-2012 |
| 20120223717 | METHOD AND APPARATUS FOR MEASURING THE ELECTRICAL IMPEDANCE PROPERTIES OF GEOLOGICAL FORMATIONS USING MULTIPLE SIMULTANEOUS CURRENT SOURCES - 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. The transmitters operate simultaneously to inject the electrical current into the subsurface area simultaneously from a number of locations | 09-06-2012 |
| 20130154651 | EARTH GROUND TESTER WITH REMOTE CONTROL - 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. | 06-20-2013 |
| 20160025885 | METHOD AND APPARATUS FOR MEASURING THE ELECTRICAL IMPEDANCE PROPERTIES OF GEOLOGICAL FORMATIONS USING MULTIPLE SIMULTANEOUS CURRENT SOURCES - 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. The transmitters operate simultaneously to inject the electrical current into the subsurface area simultaneously from a number of locations. | 01-28-2016 |
