Schlumberger Technology Corporation

Services Petroliers Schlumberger

Schlumberger Holdings Limited

Nicholas J Heaton

Chanh Cao Minh

Krishnamurthy Ganesan

Anatoly Dementyev

Yi-Qiao Song

Martin D Hurlimann

Abdurrahman Sezginer

Robert Freedman

Shin Utsuzawa

Henry N Bachman

Gabriela Leu

Cole Mann

Lalitha Venkataramanan

Charles Flaum

Soumyajit Mandal

Luis Eduardo DePavia

Boqin Q Sun

Denis Heliot

Kais Gzara

Vikas Jain

Nicholas N Bennett

Yiqiao Tang

Vassilis Varveropoulos

Ralf Heidler

Albina Mutina

David T Oliver

M Reza Taherian

Payam Tabrizi

Jack LaVigne

Eugene Janssen

Tim Hopper

Van D M Koroleva

Dylan H Davies

Scott DiPasquale

Diogenes Molina

Diogenes David Molina

Jack A La Vigne

A method can include accessing a measurement model in memory of a downhole tool; determining an optimal parameter set using a processor of the downhole tool and the measurement model; and performing at least one measurement using at least one sensor of the downhole tool operated according to the optimal parameter set.

Adaptive downhole acquisition system

A method can include controlling radio frequency emission circuitry of a nuclear magnetic resonance unit to emit radio frequency energy according to a first set of parameters that comprises a first wait time for an even number of sequence repeats with positive and negative phases and to emit radio frequency energy according to a second set of parameters that includes a second wait time for a single sequence with a single phase, where the second wait time is greater than the first wait time; and acquiring, via antenna circuitry and analog-to-digital conversion circuitry, nuclear magnetic resonance.

Nuclear magnetic resonance data acquisition system

A method can include triggering an assessment of pulse width of an X degree pulse of a downhole NMR tool; responsive to the assessment, determining an optimal pulse width of the X degree pulse; acquiring NMR measurements using the downhole NMR tool and the optimal pulse width; and characterizing a formation using at least a portion of the NMR measurements.

Downhole NMR system

A method for fabricating a magnet on a nuclear magnetic resonance logging tool includes identifying a desired magnetic field strength at a predetermined depth of investigation, receiving a set of magnet segments configured for deployment on the logging tool in a magnet arrangement which make up a magnet array on the logging tool, processing a magnetic strength and an angular offset of selected magnet segments and their unique location in the magnet array to compute corresponding magnetic field strength solutions at the predetermined depth of investigation, selecting one magnet arrangement solution that minimizes a difference between the magnetic field strength solution and the desired magnetic field strength at the predetermined depth of investigation, and deploying the magnet segments on the logging tool according to the selected magnet arrangement solution to fabricate the magnet.

Optimization of magnet arrangement for nuclear magnetic resonance well logging tools

A method for measuring one or more properties of a formation includes applying a magnetic field to a subterranean formation using a downhole tool. A radiofrequency signal is transmitted into the subterranean formation that is exposed to the magnetic field. The radiofrequency signal induces a transverse magnetization in the subterranean formation, and the transverse magnetization induces an initial voltage signal in the downhole tool. The initial voltage signal is amplified using a first amplifier in the downhole tool such that the first amplifier outputs a first amplified voltage signal. The first amplified voltage signal is introduced to an input of the first amplifier, such that the first amplifier amplifies the first amplified voltage signal and outputs a second amplified voltage signal.

Active damping for NMR logging tools

A method for determining at least one characteristic of a geological formation having a borehole therein may include collecting nuclear magnetic resonance (NMR) data of the geological formation adjacent the borehole, and collecting non-NMR data for the geological formation adjacent the wellbore. The method may further include performing a Monte Carlo analysis based upon a combination of the collected NMR and non-NMR data to determine the at least one characteristic of the geological formation having a bounded uncertainty associated therewith.

Statistical analysis of combined log data

A method to produce a magnet arrangement, the method having steps of selecting a depth of investigation to be achieved by a downhole tool, identifying a desired magnetic field strength at the depth of investigation, producing a set of magnets to be incorporated into the downhole tool, sorting the set of magnets based on a quality of each of the magnets and optimizing the set of magnets such that the quality of each of the magnets results, when arranged, in the desired magnetic field strength at the depth of investigation and wherein the optimizing minimizes a cost function of the set of magnets produced.

An arrangement for shielding an NMR tool from electromagnetic noise, having a nuclear magnetic resonance tool configured to send and receive signals, a first shield configured around a nuclear magnetic resonance antenna of the nuclear magnetic resonance tool and a second shield configured to reduce the effects of eddy currents in the first shield.

Composite noise shield for magnetic resonance tools

A method to process information from a wellbore tool is disclosed having steps of placing a wellbore nuclear magnetic resonance tool in a wellbore to a scan a geological formation, activating the nuclear magnetic resonance tool to send signals to and receive signals from the geological formation, acquiring the received signals from the geological formation wherein the received signals have an echo shape, storing the echo shape according to at least one of a quadrature phase and a nominal signal phase, computing an echo shape from all of the received signals, determining a presence of a noise from the received signals, defining a noise filter based upon the received signals from the nuclear magnetic resonance tool and using the filter to remove noise from the received signals.

Use of echo shapes in nuclear magnetic resonance log data acquisition and quality control

A method to calibrate a nuclear magnetic resonance tool is disclosed having steps of starting a nuclear magnetic resonance sequence from the nuclear magnetic resonance tool, disabling an active damping circuit in the nuclear magnetic resonance tool, collecting auxiliary calibration data for the nuclear magnetic resonance tool, estimating a natural Q value for the nuclear magnetic resonance tool, determining an optimal active damping setting for the tool, deploying the optimal active damping setting for the tool, collecting nuclear magnetic resonance response data generated from the nuclear magnetic resonance sequence and calibrating the nuclear magnetic resonance data.

Variable damping control for nuclear magnetic resonance data acquisition system to enhance oilfield logging performance

A method of obtaining nuclear magnetic resonance (NMR) data from a subterranean formation may include operating a tool in a subterranean formation for generating both NMR data and NMR scaled data based upon NMR measurements of the subterranean formation. The method also includes operating the tool for encoding and transmitting both the NMR data and NMR scaled data, and receiving and decoding, above the subterranean formation, both the NMR data and NMR scaled data from the tool. The method also includes performing error-correction of the received and decoded NMR data based upon the received and decoded NMR scaled data.

Method of performing error-correction of nuclear magnetic resonance data

A method of interpreting petrophysical measurement data include arranging measurements of at least one physical property of formations into a matrix representing the measurements and selecting a range of number of unobserved factors or latent variables for factor analysis. Factor analysis is performed on the measurement matrix and comprises performing factorization of measurements matrix into a number of factorsand performing rotation of the factorization results. Whether the factor loadings for each factor have achieved a 'simple structure' is determined and either each of the selected number of factors is associated with a physical parameter of the formations, or one is added to the number of factors and factor analysis and rotation are repeated until factor loadings of all factors have achieved 'simple structure' such that the each of the number of factors is associated with a physical property of the formations.

Identifying formation, matrix and fluid related characteristics from subsurface data using factor analysis

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.

System and method for measuring borehole geometry while drilling

A method to determine formation properties using two or more data sets in which the solutions corresponding to the data sets represent shared and distinct formation properties. The method analyzes the data sets and computes distributions for the shared and distinct formation properties from which the formation properties are determined.

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Houston, TX, United States of America

Nicholas J Heaton