Schlumberger Technology Corporation

Saudi Aramco

Saudi Arabian Oil Company

Services Petroliers Schlumberger

Schlumberger Holdings Limited

Prad Research and Development Limited

Henry N Bachman

Reza Taherian

Anatoly Dementyev

Robert Freedman

Chanh Cao Minh

Nicholas J Heaton

Philip M Singer

Andrea Valori

Yi-Qiao Song

Dean M Homan

Shouxiang Mark Ma

Edward Harrigan

Krishnamurthy Ganesan

Anthony Louis Collins

Srinand Sreedharan Karuppoor

Andrew John Carnegie

Douglas W Grant

Mark A Fredette

Pierre Henri Campanac

Andrei Davydychev

Ralf Heidler

Steve F Crary

Albina Mutina

William B Vandermeer

Yves Barriol

Tim Hopper

Gabor Hursan

Jack LaVigne

Benjamin Nicot

Farhan Ali

Steve Crary

Jack A La Vigne

Ahmed Al-Muthana

Andrei I Davydychev

Andrew J Carnegie

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

The present disclosure relates to a method that includes generating a first pulse at a first position along a geological formation with a plurality of antennae, wherein the first pulse comprises a Can-Purcell-Meiboom-Gill (CPMG) sequence, and wherein each antenna of the plurality of antennae is configured to generate NMR data via transmitting and receiving pulses into the geological formation.

Techniques for NMR logging with antenna arrays

The present disclosure relates to generating multiple depths of investigation (DOI) measurements with a saddle point design nuclear magnetic resonance sensor. In general, an NMR sensor in accordance with the present disclosure includes a first magnet at a first radial distance from a radial center, and a second magnet at a second radial distance from the radial center. The first magnet at least partially cancels out a magnetic field gradient produced by the second magnet. Further, the NMR sensor may include an antenna that generates a first set of NMR data from a first DOI by operating at a first frequency and, generates a second set of NMR data from a second DOI by operating a second frequency. Additional frequencies are possible and envisioned.

Saddle point nuclear magnetic resonance tool for measurements at multiple depths of investigation

A method for determining a wettability of a subterranean formation (or formation core) includes either deploying a nuclear magnetic resonance (NMR) logging tool in a subterranean wellbore or deploying a formation core sample in a laboratory based NMR tool. NMR measurements of the formation (or formation core) are obtained and used to compute the wettability. The NMR measurements are processed to generate a two dimensional diffusion relaxation map (a D/Tmap) which is in turn processed to compute the wettability.

NMR based reservoir wettability measurements

An apparatus for NMR properties of subsurface formations includes a magnet, a transmitter antenna and at least one of a receiver section of the transmit antenna or a separate receiver antenna having a length along the longitudinal dimension of the apparatus which is shorter than a length of the transmitter antenna along the longitudinal dimension. The apparatus includes circuitry for applying radio frequency current pulses to the entire transmitter antenna and for receiving signals by the at least one of the receiver section of the transmitter antenna and the separate receiver antenna.

Apparatus and methods for fast NMR well logging without instrument speed effects

Methods are described for wettability characterization based on NMR measurements, which are sensitive to the surface wetting conditions of oil and water at the pore scale. The described methods make use of surface relaxation effects on the NMR relaxation (T). Workflows are described to obtain wettability profiles of a porous media such as a rock either in the native state or prepared to a certain state in the laboratory. An underlying forward model is also described for the mixed wet and fractionally saturated pore spectrum. Outputs of the described inversion include continuous saturation and wettability profiles as a function of the pore sizes in the porous media, as well as an averaged value for saturation and wettability over the entire pore spectrum.

Methods for determining wettability from NMR

Subsurface formation evaluation comprising, for example, sealing a portion of a wall of a wellbore penetrating the formation, forming a hole through the sealed portion of the wellbore wall, injecting an injection fluid into the formation through the hole, and determining a saturation of the injection fluid in the formation by measuring a property of the formation proximate the hole while maintaining the sealed portion of the wellbore wall.

Formation evaluation instrument and method

In one embodiment, an apparatus includes an antenna having a conductive winding, with the antenna disposed about a channel. A characteristic improvement material is disposed between the antenna and the channel. In some embodiments, the characteristic improvement material includes at least one of a negative stiffness material or a negative Poisson's ratio material. Various systems and methods are also disclosed herein.

System and method for improving operational characteristics

A method and system for performing speed correction on nuclear magnetic resonance logging data is provided. The speed correction performed can be done on a representation of echo data received by a logging tool, and then additively applied to the echo data. Such a process can reduce or remove the amplification of noise in the echo data that is common in conventional methods of speed correction.

Methods and systems for applying speed correction fits to NMR well logging formation echo data with singular value decomposition

The present invention relates to making one or more measurements in a virgin formation using a downhole tool that includes a miniature logging tool. The downhole tool is disposed in a wellbore penetrating the formation, adjacent to the formation, and a sidetrack borehole is made into the formation. All or a portion of the miniature logging tool is deployed into the sidetrack borehole and measurements are made in the virgin formation using the miniature logging tool. The downhole tool may include a drilling/coring module, a pump module, and packers. The drilling/coring module is used to make the sidetrack borehole, and the packers and pump module can be used to create an underbalanced drilling condition in an isolated section of the wellbore.

Measurements in non-invaded formations

A technique improves the operational characteristics of a well device while the device is used in a wellbore environment. The well device benefits from a unique material, in the form of a negative stiffness material or a negative Poisson's ratio material, positioned to improve the operational characteristics of the well device. The material can be located to reduce vibration and/or other detrimental effects that can interfere with operation of the well device.

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.

Method for analyzing data having shared and distinct properties

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Missouri City, TX, United States of America

Henry N Bachman