Schlumberger Technology Corporation

Westerngeco L.l.p.

Saudi Arabian Oil Company

Jiuping Chen

David Lee Alumbaugh

Luis Eduardo DePavia

Edward Nichols

Gaelle Jannin

Liang Sun

Ping Zhang

Michael Wilt

Kevin Eyl

Richard Hunter

Robert W Tennent

Stephen Allan Horne

Nestor H Cuevas

Stephen A Horne

Huntly F Morrison

Dean M Homan

Andrew G Brooks

Daniele Colombo

David Conn

Frank Morrison

Nestor Cuevas

Pavel Annenkov

Gary Wayne Mcneice

Melisa Lourdes Ramirez Tovar

Sam Soundar

Wei Zhou

Michael W Schwartz

Communication between the surface and a downhole location, such as a bottomhole assembly and/or an RSS is performed by electromagnetic downlink. Electromagnetic signals are transmitted from the surface through the formation at a frequency of 8 Hz or greater. Electromagnetic signals are transmitted and received while drilling or during drilling activities. In this manner, information and instructions may be transmitted to the BHA while drilling.

Electromagnetic downlink while drilling

A method for steering a downhole tool includes receiving an electromagnetic (EM) signal from the downhole tool. The downhole tool is in a wellbore in a formation. The EM signal comprises a gap voltage and a gap current that are measured across a gap sub in the downhole tool. The method also includes determining a gap impedance based at least partially upon the gap voltage and the gap current. The method also includes determining a first formation resistivity at a first location in the wellbore based at least partially upon the gap impedance. The method also includes steering the downhole tool based at least partially upon the first formation resistivity.

Geo-steering using electromagnetic gap impedance data

An electromagnetic (EM) data acquisition method for a geological formation may include operating EM measurement devices to determine phase and amplitude data from the geological formation. The EM measurement devices may include at least one first EM measurement device within a borehole in the geological formation, and at least one second EM measurement device at a surface of the geological formation. The method may further include processing the phase data independent from the amplitude data to generate a geological constituent map of the geological formation, and identifying different geological constituents in the geological constituent map based upon the measured amplitude data.

Phase-based electromagnetic surveys for geological formations

A surface system for an electromagnetic telemetry remote sensing wireless system includes a surface acquisition system configured to receive wireless signals and a plurality of nodes deployed at Earth's surface in a drilling area. Each of the nodes includes a distinct pair of first and second spaced apart electrodes and is configured to digitize voltage differences between the corresponding first and second electrodes and to wirelessly transmit the digitized voltage differences to the surface acquisition system. The voltage differences include an electromagnetic signal transmitted by a downhole tool deployed in a wellbore in the drilling area.

EM-telemetry remote sensing wireless network and methods of using the same

A method for modeling an electromagnetic (EM) telemetry signal includes straightening a well in a model and dividing the well into a plurality of segments. The method also includes determining an electrical current in one or more of the segments when the well is straightened. The method also includes replacing the well with equivalent electrical sources based at least partially upon the electrical current in one or more of the segments. The method also includes bending the well back into its original shape in the model and determining the electrical current in one or more of the segments by projection when the well is back in its original shape. The method also includes summing EM fields for each of the one or more segments to estimate the EM telemetry signal.

Modelling electromagnetic telemetry signals in deviated wells

A method for placement of electrodes includes determining spatial distribution of a signal caused by generating an electromagnetic field in an instrument disposed in drill string used to drill a wellbore. The electromagnetic field comprises encoded measurements from at least one sensor associated with the instrument. Voltages induced by noise are measured across at least one pair of spaced apart electrodes placed at a plurality of positions spaced apart from a surface location of the wellbore. A spatial distribution of noise is estimated using the measured voltages. Positions for placement of at least two electrodes are selected using the spatial distribution of signal and the spatial distribution of noise.

Method for placement of surface electrodes for electromagnetic telemetry

In one embodiment, a method includes receiving one or more datasets including measured vertical electric and magnetic fields excited by one or more radial and azimuthal electric field antennas from a downtool into one or more processors, wherein each of the one or more datasets corresponds to a different position of the one or more radial azimuthal electric field antennas, simultaneously inverting the one or more datasets using the one or more processors, and as a result of the simultaneous inversion, generating by the one or more processors a three-dimensional (3D) image of a portion of the geological formation.

Hybrid electric and magnetic surface to borehole and borehole to surface method

EM-telemetry remote sensing wireless systems include a plurality of downhole tools in a drilling area, an array of electrodes at the earth's surface, a noise reduction manager, and an acquisition system. Each downhole tool transmits a modulated current into the formation to generate an electromagnetic signal at the earth's surface. The array of electrodes comprises a plurality of nodes. Each node has a plurality of electrodes that receives the signal. The signal received by the node has a signal component from the tool and a noise component from the area. The noise reduction manager has a de-mixing vector that filters the noise component of the signal and increases a signal to noise ratio. The acquisition system located on earth's surface wirelessly receives signal from each node.

A method for recovering data from a downhole tool in a wellbore includes measuring an electromagnetic signal using first and second sensors. At least a portion of the electromagnetic signal is transmitted by a downhole tool positioned in a first wellbore. The first and second sensors are each positioned at a different location along a length of a second wellbore. The electromagnetic signal measured by the first and second sensors is decoded to recover a property measured by the downhole tool.

Downhole sensing for electromagnetic telemetry

A method for signal communication between a well drilling instrument and the Earth's surface includes generating an electromagnetic field in an instrument disposed in drill string used to drill a wellbore. The electromagnetic field comprises encoded measurements from at least one sensor associated with the instrument. A signal is measured corresponding to an amplitude, phase or frequency of the electromagnetic field. The measurements are decoded from the measured signal. The measured signal comprises at least one of a voltage imparted across a capacitive electrode proximate ground surface and a galvanic electrode in contact with the ground surface, and a voltage imparted across two capacitive electrodes each proximate a ground surface and separated from each other by a known distance.

Electromagnetic telemetry using capacitive surface electrodes

Systems, methods, and apparatuses to generate a crosswell data set are described. In certain aspects, a method includes producing a first electromagnetic field at the earth's surface with a transmitter at a first location, detecting in a first borehole a first field signal induced by the first electromagnetic field, detecting in a second borehole a second field signal induced by the first electromagnetic field, and generating a crosswell data set from the first field signal and the second field signal. A formation model may be created from the crosswell data set.

Method and apparatus to generate a crosswell data set

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

To process measurement data representing a subterranean structure, a derivative of the measurement data collected by at least one survey receiver is computed, with respect to frequency. A response representing the subterranean structure is then computed based on the derivative of the measurement data, where the response contains an air-wave component that has been suppressed due to computing the derivative of the measurement data relative to at least another component that is sensitive to the subterranean structure.

Processing measurement data that involves computing a derivative of the measurement data that represents a subterranean structure

To process subterranean survey data, measurement data is collected by a receiver positioned in deep water, where the collected measurement data is responsive to signals emitted by at least one signal source located at or near an air-water interface of the body of water. The measurement data is processed to reduce a predetermined signal component.

Processing measurement data in a deep water application

A survey technique for use in a marine environment to survey a subterranean structure includes providing an arrangement of plural signal sources in a body of water to produce corresponding signals. The signals of the signal sources in the arrangement are set to cause reduction of at least one predetermined signal component in data received by a receiver in response to the signals.

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San Pablo, CA, United States of America

Jiuping Chen