Schlumberger Technology Corporation

Westerngeco L.l.p.

Chevron U.s.a. Inc.

Westerngreco L.l.c.

David Lee Alumbaugh

Edward Nichols

Tarek M Habashy

Jiuping Chen

Guozhong Gao

Ping Zhang

Aria Abubakar

H Frank Morrison

Andrea Zerilli

Kevin Eyl

James P Brady

Frank Morrison

Nestor Cuevas

Cyrille Levesque

Jacques R Tabanou

Richard A Rosthal

Jean P Seydoux

Jian Yang

Hong Zhang

Andrew Hawthorn

John Paul Horkowitz

Jianguo Liu

Leendert Combee

Martin N Howlid

Ugo Conti

Michael L Oristaglio

Kambiz A Safinya

Gary Michael Hoversten

Stephen Allan Horne

Stephen A Horne

Huntly F Morrison

Michael Wilt

Cengiz Esmersoy

Michael John Tompkins

Vladimir L'vovich Druskin

Steve Horne

Vanessa Claire Brown

A method analyzes a subterranean formation. At least one property of a well casing in the subterranean formation is determined and a plurality of current source vectors at respective positions along a trajectory of the well casing are determined. The effect of the well casing is determined based upon the plurality of current source vectors and the at least one property of the well casing.

Analyzing subterranean formation with current source vectors

A surface electromagnetic survey system and method for detecting a fracture or fracture zone in a rock formation are provided. The system includes an electromagnetic source configured to generate an electromagnetic field in the vicinity of or at a surface of the rock formation. The electromagnetic source includes one or more electric dipole sources that are arranged so as to generate a substantially vertical electric field. The system also includes an electromagnetic receiver associated with the electromagnetic source, the electromagnetic receiver being configured to measure a component of the electromagnetic field at the surface of the rock formation; and a processor configured to convert the measured component of the electromagnetic field measured at the electromagnetic receiver into an electromagnetic field response per unit moment of the electromagnetic source. The electromagnetic field response provides information about characteristics parameters of the fracture or fracture zone.

System and method for detecting a fracture in a rock formation using an electromagnetic source

A drill string is disposed in the borehole having a BHA and a drill bit advancing the borehole. Among other BHA components, including a telemetry unit and a data acquisition unit, in a surface-to-borehole configuration a receiver (or receiver array) is positioned immediately proximate the drill bit in the borehole, while a source (or source array) is positioned at the Earth's surface. Alternatively, in a borehole-to-surface configuration the source may be positioned immediately proximate the drill bit in the borehole while a receiver (or receiver array) is positioned at the surface. The surface-to-borehole, or borehole-to-surface, system enables an electromagnetic look about while drilling operations are underway.

Systems and methods for electromagnetic detection of a formation anomaly from a near bit location while drilling

A technique provides a methodology for improving surveys of subterranean regions. The methodology comprises estimating macro anisotropy and an intrinsic or micro anisotropy of an overburden. A surface electromagnetic survey is conducted, and the data from the survey is inverted based on or including information gained from estimating the macro anisotropy and/or intrinsic anisotropy. A processor system can be used to conduct the inversion with the adjustments for anisotropy to improve the information provided by the survey.

System and method for improving surface electromagnetic surveys

A system and a method for time lapse monitoring of a target feature within a rock formation are provided. The system includes a data weighted electromagnetic source configured to generate an electromagnetic field in vicinity or at a surface of the rock formation; and an electromagnetic receiver configured to measure a component of the electromagnetic field generated by the source. The data weighted electromagnetic source includes a plurality of electromagnetic sources and an electromagnetic field contribution from each electromagnetic source is weighted so as to enhance the component of the electromagnetic field measured by the electromagnetic receiver.

Method and system of using a data weighted electromagnetic source for time-lapse monitoring of a reservoir production or hydraulic fracturing

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

Methods and related systems are described for measuring naturally occurring electromagnetic fields both at the earth's surface as well as downhole. These fields originate from currents in the ionosphere above the earth, and are the same fields as employed by known magnetotelluric geophysical methods based on surface measurements. Some embodiments are especially useful in horizontal wells that are uncased at depth, although some embodiments are also useful in normal vertical wells that are both uncased or cased with a conductive liner. The method includes receiving downhole electromagnetic survey data of the naturally occurring electromagnetic fields obtained using a downhole receiver deployed at a first location in a borehole. A second set of electromagnetic survey data of the naturally occurring electromagnetic fields is also received that has been obtained using a receiver deployed at a second location. A transfer function is estimated between the first and second locations for portions of the electromagnetic fields based on the two sets of electromagnetic survey data.

Electromagnetic survey using naturally occurring electromagnetic fields as a source

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.

Characterizing an earth subterranean structure by iteratively performing inversion based on a function

A technique that is usable with a well includes providing a model so predict measurements that are received by receivers due to transmissions by sources based on estimated positions of the receivers relative to the sources. The estimated positions each have at least two dimensions. At least some of the receivers and the sources are located in the well. On a computer, the estimated positions are automatically refined based on a comparison of the predicted measurements and actual measurements that are obtained by the receivers.

Method and apparatus to automatically recover well geometry from low frequency electromagnetic signal measurements

Methods and related systems are described for making an electromagnetic induction survey of a formation surrounding a cased section of a borehole. An electromagnetic transmitter and/or receiver are deployed into the cased section of the borehole. One or more additional devices are used to measure the properties of a conductive casing relating to conductivity, thickness and magnetic permeability. A casing coefficient is then calculated that can then be used for the processing of the deep-sensing induction measurements.

Measuring casing attenuation coefficient for electro-magnetics measurements

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 update a subterranean model, an initial subterranean model is provided, and based on the initial subterranean model, changes to subterranean parameters are predicted using a reservoir simulator. Electromagnetic data representing characteristics of a subterranean structure is computed according to the predicted changes to the subterranean parameters, and the initial subterranean model is modified based on comparing the computed electromagnetic data with observed electromagnetic data.

Updating a subterranean model using at least electromagnetic data

To analyze content of a subterranean structure, electric field measurements at plural source-receiver azimuths in a predefined range are received. Total magnetic field measurements are also received at plural source-receiver azimuths in the predefined range. The electric field measurements and the total magnetic field measurements are provided to an analysis module to enable determination of electrical resistivity anisotropy of the subterranean structure.

Providing measurements to enable determination of electrical resistivity anisotropy of a subterranean structure

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Berkeley, CA, United States of America

David Lee Alumbaugh