Schlumberger Technology Corporation

Schlumberger Technology Corporaton

Christian Stoller

Peter D Wraight

Tong Zhou

Bradley Albert Roscoe

Michael Lynn Evans

David Rose

Matthieu Simon

Sicco Beekman

Robert A Adolph

Joel Lee Groves

John J Simonetti

Luke T Perkins

Richard J Radtke

Olivier G Philip

Kenneth Edward Stephenson

Wolfgang P Ziegler

Markus Berheide

Avtandil Tkabladze

Arthur J Becker

James A Grau

Jeffrey Miles

Zilu Zhou

Donald C McKeon

James Leslie Thornton

Anthony Durkowski

Libai Xu

Marie-Laure Mauborgne

Fabien Haranger

Mauro Manclossi

Christopher Del Campo

John E Edwards

Jan Smits

Roger Griffiths

Patrick J Fisseler

Ronald E Plasek

Cornelis Huiszoon

Nicolas Renoux

Frederic Gicquel

Laurent Villegas

Irina Molodetsky

Nihal I Wijeyesekera

Urmi DasGupta

Brad Roscoe

Laurent Laval

Arlene O Siefker-Radtke

Francoise Allioli

Adil Busaidy

Ken Stephenson

Jim A Grau

Donna Simonetti

Andrew Bazarko

Albert Hort

Ahmed Amine Mahjoub

Reza Taherian

Gary Martin Oddie

Jani Petteri Reijonen

Charles Flaum

Dominic Joseph Brady

Felix K Chen

Jean-Pierre Poyet

Richard G Saenger

Kevin Scott McKinny

Bruno Jorion

Alice Chougnet-Sirapian

Arthur D Liberman

Jiaxin Wang

Libo Yang

Didier Fouillou

Onur Ozen

Sebastien Isambert

Raju M Eason

Françoise Allioli

Dennis J Pittman

Robert Little

Emmanuel Fayeulle

Scott H Fricke

Art Liberman

Laurent Labous

Verna L Lomax

Sunil N Gulrajani

Xavier Herve

Pascal Millot

Michael D Hackbart

Frederic Gicquiel

Avto Tkabladze

The current disclosure is related to a downhole tool that comprises an electronic photon generator and at least one detector. The electronic photon generator comprises a cathode configured to emit electrons, a first target configured to generate photons when struck by the electrons, a second target configured to generate photons when struck by the electrons, and a beam steering device that directs the electrons to a first or second target. The at least one detector is configured to detect at least some of the photons emitted by the first target and at least some of the photons emitted by the second target.

X-ray downhole tool with at least two targets and at least one measurement detector

Disclosed is a radiation logging tool, comprising a tool housing; a compact generator that produces radiation; a power supply coupled to the compact generator; and control circuitry. Embodiments of the compact generator comprise a generator vacuum tube comprising a source generating charged particles, and a target onto which the charged particles are directed; and a high voltage supply comprising a high voltage multiplier ladder located laterally adjacent to the generator vacuum tube. The high voltage supply applies a high voltage between the source and the target to accelerate the charged particles to a predetermined energy level. The compact generator also includes an electrical coupling between an output of the high voltage supply and the target of the generator vacuum tube to accommodate the collocated positions of the generator vacuum tube and the high voltage power supply.

High voltage supply for compact radiation generator

A method for making natural gamma ray measurements of a subterranean formation includes causing a natural gamma ray sensor on an LWD tool to acquire a spectral gamma ray measurement while a neutron source emits neutrons. The measurements are evaluated to compute first and second drilling fluid activation corrections using corresponding first and second correction methodologies. The first and second corrections are processed to compute a third drilling fluid activation correction which is applied to the gamma ray measurements to compute a corrected total natural gamma ray measurement.

Drilling fluid activation correction methodology

A presence of cement may be identified based on a downhole tool that may emit neutrons into a wellbore having at least one cement casing. The neutrons may interact with the particular material via inelastic scattering, inelastic neutron reactions, capture of neutrons and/or neutron activation through one of these reactions and cause a material to emit an energy spectrum of gamma rays, and wherein the downhole tool is configured to detect an energy spectrum of the gamma rays that is specific to at least one of a plurality of elements and associated a region within the wellbore. An amount of elements, such as calcium and silicon, may be determined from the gamma ray spectra that may indicate a present of cement within the wellbore.

Systems and methods for determining the presence of cement behind at least one casing using spectroscopy measurement

A method for determining azimuthal formation information using neutron activation, wherein the formation is activated by a neutron source and the activation signal is measured by at least one detector trailing the neutron source during the logging operation. The number of detected gamma rays as a function of the detector azimuth may be used to provide azimuthal information for determining an image of the formation surrounding the borehole.

Formation imaging using neutron activation

The present disclosure describes a downhole tool including an electrically operated radiation generator that selectively output radiation to a surrounding environment based at least in part on supply of electrical power; and a control system that determines likelihood of exposing living beings in the surrounding environment to output radiation by determining whether one or more check conditions is met; determine that each of the one or more check conditions is met before instructing the electrically operated radiation generator to output radiation; and instruct the electrically operated radiation generator to cease output of radiation when at least one of the one or more check conditions is no longer met.

Control of electrically operated radiation generators

Systems, methods, and devices for inelastic gamma-ray logging are provided. In one embodiment, such a method includes emitting neutrons into a subterranean formation from a downhole tool to produce inelastic gamma-rays, detecting a portion of the inelastic gamma-rays that scatter back to the downhole tool to obtain an inelastic gamma-ray signal, and determining a property of the subterranean formation based at least in part on the inelastic gamma-ray signal. The inelastic gamma-ray signal may be substantially free of epithermal and thermal neutron capture background.

Optimization of neutron-gamma tools for inelastic gamma-ray logging

A method for determining a fractional volume of at least one component of a formation includes entering into a computer a number of detected radiation events resulting from imparting neutrons into the formation at an energy level of at least 1 million electron volts (MeV). The detected radiation events correspond to at least one of an energy level of the imparted neutrons and thermal or epithermal energy neutrons. A measurement of at least one additional petrophysical parameter of the formation is made. The at least one additional petrophysical parameter measurement and at least one of a fast neutron cross-section and a thermal neutron cross-section determined from the detected radiation events are used in the computer to determine the fractional volume of the at least one component of the formation. In another embodiment, the fast neutron cross-section and the thermal neutron cross-section may be used on combination to determine the fractional volume.

Method for using neutron interaction cross section to interpret neutron measurements

A method for evaluating cement in a cased wellbore in a geological formation includes placing a downhole tool into the cased wellbore, where the cased wellbore has been cased using a cement that contains a particular material. The method includes emitting neutrons using the downhole tool, wherein the neutrons interact with the particular material via inelastic scattering or capture of neutrons and cause the material to emit an energy spectrum of the gamma rays associated with the material or wherein the time-based measurement of gamma rays or neutrons is influenced by the presence of the material. The method includes using the downhole tool to detect radiation radiation, such as the energy spectrum of the gamma rays, or a die-away pattern of the gamma rays or neutrons that indicates a presence of the particular material and enable to estimate a parameter of the cement.

Cement evaluation using neutron tool

A downhole tool includes a radiation generator configured to output radiation using electrical power received from a power supply. A first portion of the radiation is emitted into a surrounding sub-surface formation. The downhole tool also includes a radiation detector coupled proximate the radiation generator. The radiation detector includes a micromesh gaseous detector, and the radiation detector is configured to output a measurement signal based at least in part on interaction between a second portion of the radiation output by the radiation generator and the radiation detector. Additionally, the downhole tool includes a control system communicatively coupled to the radiation generator and the radiation detector. The control system is configured to determine measured characteristics of the radiation output from the radiation generator based at least in part on the measurement signal and to control operation of the radiation generator based at least in part on the measured characteristics.

Systems and methods for monitoring radiation in well logging

A downhole tool operable for conveyance within a wellbore extending into a subterranean formation, and for obtaining one or more measurements of the subterranean formation, wherein the downhole tool comprises a sensor, a pressure housing containing the sensor and mounted on an external surface of the downhole tool, and a sliding stabilizer covering the pressure housing.

Sensor standoff

Growing community of inventors

Princeton Junction, NJ, United States of America

Christian Stoller