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Guozhong Gao
Guozhong Gao, Watertown, MA US
| Patent application number | Description | Published |
|---|---|---|
| 20100277177 | ANALYSIS OF SUBSURFACE ELECTROMAGNETIC DATA THROUGH INVERSION WITH CONSTRAINED CASING CORRECTION COEFFICIENTS - Methods and related systems are described for analyzing electromagnetic survey data. Electromagnetic survey data of a subterranean formation is obtained using at least a downhole transceiver deployed in a borehole and a transceiver positioned on the surface, or in the same or another borehole. Limits are defined for casing correction coefficients that account for effects of the borehole casing. A constrained inversion process is performed solving for the casing correction coefficients within the defined limits, and for one or more parameters of a model representing attributes, such as resistivity, of the subterranean formation. | 11-04-2010 |
| 20100321023 | ATTENUATION OF ELECTROMAGNETIC SIGNALS PASSING THROUGH CONDUCTIVE MATERIAL - The present disclosure relates to determining the attenuation of an electromagnetic signal passing through a conductive material. An antenna is provided and placed in relatively close proximity to the conductive material. An alternating current is passed through the antenna and the impedance of the antenna is measured. The attenuation is determined using the measured impedance. A single frequency measurement may be made, or multiple measurements using different frequencies may be made. Grouped parameters based on properties of the material and the frequency of the current are used to relate the coil impedance to the attenuation. A current frequency for which the ratio of the antenna's resistive part of the impedance to the angular frequency of the current is substantially insensitive to at least one of the parameters is preferred. | 12-23-2010 |
| 20110012620 | CORRECTION FACTORS FOR ELECTROMAGNETIC MEASUREMENTS MADE THROUGH CONDUCTIVE MATERIAL - The present disclosure relates to determining attenuation factors relating to an electromagnetic signal passing through, a conductive material seen by a real sensor. A sensor is provided and disposed proximate to the material. An alternating current is passed through the sensor and the impedance of the sensor is measured. The impedance of an ideal coil is obtained from the measured impedance using electromagnetic modeling combined with a circuit analysis of the coil impedance, and the attenuation factors for the real coil in straight or feedback mode are determined by electromagnetic modeling of casing attenuation factors and impedance of an ideal coil combined with equivalent circuit modeling of the sensor transfer functions. The attenuation factors seen by the real sensor may be determined in real-time or post-survey. The material may be magnetic or non-magnetic. | 01-20-2011 |
Guozhong Gao, Albany, CA US
| Patent application number | Description | Published |
|---|---|---|
| 20090005993 | Characterizing an Earth Subterranean Structure by Iteratively Performing Inversion Based on a Function - To characterize an earth subterranean structure using a measurement assembly including electromagnetic (EM) receivers and one or more EM sources, measured voltage data collected by EM receivers in response to transmission by one or more EM sources is received. Based on a model, predicted EM data is computed. Inversion is iteratively performed according to a function that computes a difference between the measured voltage data and a product of a term containing the predicted EM data and a term containing distortion data that accounts at least for distortion effect by an environment of the measurement assembly. The inversion is iteratively performed to solve for parameters of the model and the distortion data. | 01-01-2009 |
| 20090157320 | CHARACTERIZING AN EARTH SUBTERRANEAN STRUCTURE BY ITERATIVELY PERFORMING INVERSION BASED ON A FUNCTION - To characterize an earth subterranean structure using a measurement assembly including electromagnetic (EM) receivers and one or more EM sources, measured voltage data collected by EM receivers in response to transmission by one or more EM sources is received. Based on a model, predicted EM data is computed. Inversion is iteratively performed according to a function that computes a difference between the measured voltage data and a product of a term containing the predicted EM data and a term containing distortion data that accounts at least for distortion effect by an environment of the measurement assembly. The inversion is iteratively performed to solve for parameters of the model and the distortion data. | 06-18-2009 |
| 20100305863 | Characterizing an Earth Subterranean Structure by Iteratively Performing Inversion Based on a Function - To characterize an earth subterranean structure using a measurement assembly including electromagnetic (EM) receivers and one or more EM sources, measured voltage data collected by EM receivers in response to transmission by one or more EM sources is received. Based on a model, predicted EM data is computed. Inversion is iteratively performed according to a function that computes a difference between the measured voltage data and a product of a term containing the predicted EM data and a term containing distortion data that accounts at least for distortion effect by an environment of the measurement assembly. The inversion is iteratively performed to solve for parameters of the model and the distortion data. | 12-02-2010 |
Guozhong Gao, Berkeley, CA US
| Patent application number | Description | Published |
|---|---|---|
| 20100171501 | PROVIDING A TOW CABLE HAVING PLURAL ELECTROMAGNETIC RECEIVERS AND ONE OR MORE ELECTROMAGNETIC SOURCES - 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. | 07-08-2010 |
Guozhong Gao, El Cerrito, CA US
| Patent application number | Description | Published |
|---|---|---|
| 20100097066 | Casing Correction in Non-magnetic Casing by the Measurement of the Impedance of a Transmitter or Receiver - Methods and related systems are described for determining the casing attenuation factor for various frequencies from measurements of the impedance of the transmitting or receiving coil of wire of. The compensation is based on two relationships. The first relationship is between one or more measured impedance parameters and the product of casing conductivity, casing thickness and electromagnetic frequency. The second relationship is between the casing correction factor and the product of casing conductivity, casing thickness and electromagnetic frequency. | 04-22-2010 |
Guozhong Gao, Arlington, MA US
| Patent application number | Description | Published |
|---|---|---|
| 20120116679 | PROVIDING A TOW CABLE HAVING PLURAL ELECTROMAGNETIC RECEIVERS AND ONE OR MORE ELECTROMAGNETIC SOURCES - 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. | 05-10-2012 |