Schlumberger Technology Corporation

Services Petroliers Schlumberger

Schlumberger Holdings Limited

Prad Research and Development Limited

Robert A Adolph

Christian Stoller

Michael Lynn Evans

Bradley Albert Roscoe

Richard J Radtke

Patrick J Fisseler

Peter D Wraight

Luke T Perkins

Jan Smits

W Robert Sloan

Kevin Lee Hiles

Lo&iuml;c Vild&eacute;

Jacques A Jundt

Patrice Ligneul

Joel Lee Groves

Sicco Beekman

Wolfgang P Ziegler

Paul Wanjau

Ronald E Plasek

Luca Ortenzi

Vincent Ernst

Mike Evans

Jack L Purcell

Tadashi Tajima

Scott H Fricke

Loïc Vildé

Nihal Ian Wijeyesekera

Tim Quinlan

H&eacute;l&egrave;ne C Climent

Nancy S Borkowski

Julien Tavernier

John E Edwards

A system includes a downhole tool having a first load of a plurality of loads that receive power from a system power supply. The downhole tool includes a second load of the plurality of loads configured to receive power from the system power supply. The downhole tool includes control electronics that control a temporal distribution of power delivered from the system power supply to at least the first and second load such that timing of power drawn by the first load is based on timing of power drawn by the second load.

Downhole tool power balancing

Disclosed herein is a system for fast gain regulation in a gamma-ray spectroscopy instrument. The system includes a detector configured to generate a signal indicative of energy arriving at the detector, and a processor configured to determine one or more system performance indicators. The system also includes a controller configured to compute a first gain correction term based on one of more system performance indicators and change the device gain based on the computed first gain correction term.

System and method for gain regulation

The present disclosure describes a neutron generator including an ion source that generates ions; a target that outputs neutrons when the ions impact the target; one or more power supplies that supply electrical power to the ion source and the target; and a control system. The control system determines one or more rules that describe relationships between operational parameters, useful life, reliability, neutron output, environment, and constraints of the neutron generators; determines one or more operational parameter setpoints based at least in part on the one or more rules; and instructs the one or more power supplies to adjust electrical power supplied to the ion source, the target, or both based at least in part on the one or more operational parameter setpoints.

Electrically operated radiation source operating power, reliability and life management systems and methods

Systems, methods, and devices for thermally protecting a scintillator crystal of a scintillation detector are provided. In one example, a thermally-protected scintillator may include a scintillator crystal and a thermal protection element, which may partially surround the scintillator crystal. The thermal protection element may be configured to prevent the scintillator crystal from experiencing a rate of change in temperature sufficient to cause cracking or non-uniform light output, or a combination thereof.

Thermally-protected scintillation detector

Systems, methods, and devices involving segmented radiation detectors are provided. For example, a segmented radiation detector may include a segmented scintillator and an optical-to-electrical converter. The segmented scintillator may have several segments that convert radiation to light, at least one of which may detect radiation arriving from an azimuthal angle around an axis of the segmented scintillator. The optical-to-electrical converter may be coupled to the segmented scintillator. The optical-to-electrical converter may receive the light from the segments of the segmented scintillator and output respective electrical signals corresponding to the amount of radiation detected by each segment.

Segmented radiation detector and apparatus and method for using same

Disclosed herein is a system for fast gain regulation in a gamma-ray spectroscopy instrument. The system includes a detector configured to generate a signal indicative of energy arriving at the detector, and a processor configured to determine one or more system performance indicators. The system also includes a controller configured to compute a first gain correction term based on one of more system performance indicators and change the device gain based on the computed first gain correction tem.

A method for regulating output of a high voltage generator includes monitoring a voltage output of the generator and comparing it to a voltage setpoint to generate an error signal. A load on the generator is monitored to generate a load signal. The load signal is conducted to a feedforward signal generator. The feedforward signal generator is configured to produce a feedforward signal corresponding to the load and to at least one parameter related to an output impedance of the high voltage generator. The error signal is conducted to a high voltage regulation loop. The control loop output and the feedforward signal generator output are coupled to a driver for the high voltage generator.

Method and apparatus for regulating high voltage

A method is described for obtaining an accurate and precise value for radiation output of a radiation generator. Radiation is generated in the radiation generator, and the radiation output of the radiation generator is measured using a radiation monitoring device. An instantaneous inferred radiation output is determined from operating parameters of the radiation generator, and over a period of time a calibration factor between the measured and the instantaneous inferred radiation output is determined. The accurate and precise value for radiation output is determined from the instantaneous inferred radiation output and the determined calibration factor.

Monitoring the output of a radiation generator

A method for operating a pulsed neutron generator includes adjusting a target current of the neutron generator to a preselected value. A parameter related to a neutron output of the neutron generator is measured. A target voltage of the neutron generator is adjusted to maintain the measured parameter within a predetermined range.

Methods for controlling ion beam and target voltage in a neutron generator for improved performance

A method for determining at least one formation property calculated from neutron measurements acquired with a downhole tool includes emitting neutrons from a source in the tool into the formation, detecting neutrons with at least one detector in the downhole tool, calculating a first slowing-down length (L) based on the detected neutrons, and deriving a second slowing-down length (L) based on the first slowing-down length (L). Further steps include deriving a correlation function for relating slowing-down lengths from a first tool to slowing-down lengths associated with a different source, wherein the correlation function depends on formation properties such as bulk density; and applying the correlation function to the slowing-down length of the first tool to derive the slowing-down length of the second tool. A method for determining a thermal neutron formation porosity based on a slowing-down length from epithermal neutron measurements from an electronic neutron source includes converting the slowing-down length into a computed neutron slowing-down length from thermal neutron measurements from a chemical neutron source, wherein the converting uses a correlation function that depends on formation bulk density; deriving a thermal neutron countrate ratio based on the computed neutron slowing-down length, wherein the deriving uses a function that depends on the formation bulk density and formation sigma; and computing the thermal neutron formation porosity from the thermal neutron countrate ratio.

Thermal neutron porosity from neutron slowing-down length, formation thermal neutron capture cross section, and bulk density

A tool for formation logging includes a support configured for movement in a borehole; a neutron source disposed on the support; a neutron monitor disposed on the support and configured to monitor an output of the neutron source; a gamma-ray detector disposed on the support and spaced apart from the neutron source; and a shielding material disposed between the gamma-ray detector and the neutron source.

Sigma/porosity tools with neutron monitors

An apparatus for measuring characteristics of earth formations surrounding a borehole, comprises a resistivity measurement device having a multiplicity of antennae spaced between each other in a longitudinal direction of the apparatus. A neutron measurement device of the apparatus comprises at least a neutron source and at least a neutron detector, each of the neutron detectors being at a distance from the neutron source in the longitudinal direction of the apparatus. The multiplicity of antennae are interleaved with the neutron measurement device in order to reduce a total length of the apparatus and in order to allow a determined area of the earth formation to be measured simultaneously using the neutron measurement device and the resistivity measurement device.

Integrated logging tool for borehole

A method for formation logging includes acquiring measurements of neutron-induced signals having azimuthal information using a neutron tool; processing the measurements into a plurality of azimuthal sector data for each acquisition interval; and deriving a selected parameter from the plurality of azimuthal sector data. A logging tool includes a housing adapted to move in a borehole; a circuitry having memories for storing neutron-induced measurements; a neutron source disposed in the housing; and at least one detector bank disposed in the housing spaced apart from the neutron source, wherein each of the at least one detector bank comprises at least one detector disposed around a periphery of the housing such that the at least one detector is more sensitive to signals from an azimuthal direction, and wherein count rates detected by each of the at least one detector are separately stored in the memories.

Growing community of inventors

Houston, TX, United States of America

Robert A Adolph