University of California

Schlumberger Technology Corporation

Westerngeco L.l.p.

Groundmetrics, Inc.

H Frank Morrison

David Lee Alumbaugh

Guozhong Gao

Richard A Rosthal

Edward Nichols

Andrew Dennis Hibbs

Hong Zhang

Nestor Cuevas

Cyrille Levesque

Andrea Zerilli

Tarek M Habashy

Leendert Combee

Luis Eduardo DePavia

Martin N Howlid

Michael Wilt

Kambiz A Safinya

James P Brady

Michael L Oristaglio

Garrett Kramer

Erika Gasperikova

Clifford J Schenkel

Paulo J Monteiro

Alessandro Ratti

A system for mapping a depth of an aquifer and determining the presence and salinity of water from the aquifer and methods for using the making/using the same includes a central processor. One or more horizontal loop transmitters can be coupled to the central processor, wherein said one or more horizontal loop transmitters produce a first half-sine pulse of magnetic field at a first pulse duration for measuring the resistivity of a ground surface. The one or more horizontal loop transmitters can produce a second sequence of half-sine pulses at a second frequency for creating an excitation field for magnetic resonance sounding. A multi-turn receiver loop antenna can also be coupled to the central processor, wherein said multi-turn receiver loop antenna receives an induced magnetic field from said one or more horizontal loop transmitters that is representative of the depth of an aquifer and the salinity of the water.

System and method for groundwater detection and evaluation

A method for efficiently calculating a subsurface distribution of electrical resistivity or conductivity generated by an electromagnetic (EM) source is provided wherein a significant fraction of the electric current produced by a source flows along a casing of a borehole. The method is comprised of two steps: calculating EM fields produced by the casing in the background lithology; and calculating EM fields caused by a resistivity anomaly in the presence of an EM field produced by the casing within a subsurface or survey model that does not include the casing.

Subsurface resistivity modeling with electromagnetic fields using a conductive casing

Methods and systems are provided to determine a property of an earth formation, comprising a mobile transmitter disposed at a predetermined elevated height above a surface of the earth formation, and one or more receivers moveably disposed in a wellbore penetrating the earth formation. Electromagnetic energy is transmitted from the mobile transmitter into the formation from a plurality of locations; and at the one or more receivers a signal is measured. Using the signal received by the one or more receivers, a property of the formation, such as resistivity, can be determined and mapped.

System and method for elevated source to borehole electromagnetic survey

A system enables a borehole casing to be used to connection with establishing electromagnetic fields within the earth at the depth of formations of interest over a significant surface area. A particular advantage is that a borehole casing can be used as an essential part of the system, without needing to open the borehole.

System and method to induce an electromagnetic field within the earth

A system and method are provided for delivering current to a lower exposed end of a well in which a source of current is connected to a middle section of a well casing or tubing inserted in the casing with the middle section being electrically isolated from a first or upper section by an insulative coupler and treated to be electrically resistive. A cable is attached to the middle section and used to deliver current along the wall of the middle section to the lower exposed end such that the lower exposed end is used to generate an electric field in nearby geological zones. Changes in the generated electric field resulting from the nature of materials in the geological zones can be detected by surface or below ground monitors or sensors.

System and method for mapping deep anomalous zones of electrical resistivity

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.

Providing a tow cable having plural electromagnetic receivers and one or more electromagnetic sources

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.

Attenuation of electromagnetic signals passing through conductive material

To perform a marine survey of a subterranean structure, a vertically oriented electromagnetic (EM) source is positioned in a body of water, where the EM source is coincident with an EM receiver. The EM source is activated to cause transmission of EM energy into the subterranean structure. After deactivation of the EM source, an EM field affected by the subterranean structure is measured by the EM receiver. In an alternative implementation, a survey system is provided that has a continuous wave EM source, a main EM receiver, and an auxiliary EM receiver.

Surveying a subterranean structure using a vertically oriented electromagnetic source

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.

Correction factors for electromagnetic measurements made through conductive material

A system to perform a marine subterranean survey includes at least one vertical electromagnetic (EM) source and at least one EM receiver to measure a response of a subterranean structure that is responsive to EM signals produced by the vertical EM source. At least one tow cable is used to tow the EM source and EM receiver through a body of water.

Surveying using vertical electromagnetic sources that are towed along with survey receivers

A method of determining the position and condition of reinforcing steel embedded in concrete is described. The method is non-invasive. Electrodes are use to carry out the method by contacting the outer surface of the concrete. The method measures the impedance of selected regions of the concrete by measuring the voltage generated across said selected regions by a current flowing through the concrete.

Non-destructive method of determining the position and condition of

A prospecting system uses a rotating superconducting electromagnetic source which is swept over a frequency range with a magnetometer type receiver sensing the induced field. The effective dipole is rotated in a horizontal plane parallel to the ground surface with the sensed induced magnetic field being in the vertical axis.

Growing community of inventors

Berkeley, CA, United States of America

H Frank Morrison