Schlumberger Technology Corporation

Other

Luis Eduardo DePavia

Jiuping Chen

Liang Sun

David Conn

Gaelle Jannin

Julius Kusuma

Robert W Tennent

Edward Nichols

Arnaud Jarrot

Hong Zhang

Adeel Mukhtar

Abdurrahman Sezginer

Yi-Qiao Song

Guozhong Gao

David T Oliver

Richard Hunter

Tim Hopper

Dean M Homan

Robert Freedman

Richard A Rosthal

Andrew G Brooks

Martin D Hurlimann

Nicholas J Heaton

Michael Wilt

Andriy Gelman

Arnaud Croux

H Frank Morrison

Frank Morrison

Bruno Jorion

Yuji Hosoda

Ali K Toufaily

Garrett Kramer

Vamsi Vytla

Michael W Schwartz

Thor Johnsen

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

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 configuring transmission signals is disclosed. The method includes receiving a signal from a downhole tool in a wellbore. The signal may include a telemetry portion and a noise portion. The method also includes reproducing the telemetry portion based at least partially on the signal. Further, the method includes subtracting the telemetry portion from the signal. The method includes estimating, based at least partially on the subtraction, the noise portion of the signal. The method also includes altering a transmission configuration of the downhole tool based at least partially on the noise portion of the signal.

Methods and systems for spectrum estimation for measure while drilling telemetry in a well system

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

A saver sub includes a hollow, tubular body having an upper portion and a lower portion. The upper portion is coupled to a kelly or a top drive, and the lower portion is coupled to a drill string. An insulation layer is positioned between the upper portion and the lower portion.

System and method for reducing rig noise transmitted downhole

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 improving a quality of data received from a downhole tool in a wellbore includes receiving a first block of data from a downhole tool in a wellbore. The first block of data represents a first measurement captured by the downhole tool during a first period of time. At least a portion of a bit budget for a second block of data is allocated to the first block of data to produce an updated first block of data. The method also includes receiving the second block of data from the downhole tool in the wellbore. The second block of data represents a second measurement captured by the downhole tool during a second period of time.

Real-time electromagnetic telemetry system

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

A method for signal communication between a well drilling instrument and the Earths surface includes generating an electromagnetic field in an instrument disposed in drill string used to drill a wellbore. The electromagnetic field includes encoded measurements from at least one sensor associated with the instrument. A signal corresponding to an amplitude and/or phase of the electromagnetic field is measured between the drill string and a surface electrode when the drill string is substantially electrically isolated from a well casing. A signal corresponding to the amplitude and/or phase is measured between the casing and a surface electrode when the casing and the drill string are in electrical contact with each other.

Methods and systems to boost surface detected electromagnetic telemetry signal strength

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 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 includes encoded measurements from at least one sensor associated with the instrument. A signal corresponding to an amplitude of the electromagnetic field is measured and the measurements from the measured signal are decoded. The signal comprises a voltage measured across electrodes or a voltage induced in an electromagnetic receiver disposed at a selected depth below the Earth's surface. The selected depth is at least the depth of a formation below the water table having a highest resistivity within 500 meters of the surface.

Electromagnetic telemetry for measurement and logging while drilling and magnetic ranging between wellbores

A method and system for determining a geometry of a borehole includes forming an nuclear magnetic resonance (NMR) caliper with a plurality of coils and coupling the NMR caliper to a borehole assembly. The NMR caliper may be calibrated for porosity and the T2 of the drilling mud, prior to drilling, at the surface. After drilling commences, scans of the borehole may be conducted with each coil of the NMR caliper. Each scan may include propagating RF energy across a range of frequencies with each coil in order to excite a NMR signal at varying depths. Borehole wall distances from the NMR caliper may be determined by reviewing a plurality of T2 distributions from CPMG measurements derived from the scans. In some embodiments, borehole wall distances from the NMR caliper may be determined by reviewing porosity values derived from the scans.

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Sugar Land, TX, United States of America

Luis Eduardo DePavia