Schlumberger Technology Corporation

Mark Flaum

Lalitha Venkataramanan

Martin D Hurlimann

Charles Flaum

Brian Oliver Clark

Terizhandur S Ramakrishnan

Yi-Qiao Song

Robert L Kleinberg

Jaideva C Goswami

Shin Utsuzawa

Jan Stefan Morley

Yiqiao Tang

William E Kenyon

David Furse Allen

Tancredi Botto

Miguel F Pabon

Irfan Bulu

Edmund J Fordham

Bo Hu

Jane Troutner

Magnet design is provided. A method customizes a magnetic field uniformity of a magnet by introducing one or more gaps between pieces of the magnet assembly.

Magnet design

A method and system for detecting an anomaly in measurement data captured by a downhole tool is disclosed provided. In the method and system, measurement data comprising a plurality of measurement channels is obtained and reference data including healthy reference data and faulty reference data is also obtained. The measurement data is preprocessed by modeling at least one measurement channel of the plurality of measurement channels using modeling parameters to produce pre-processed measurement data. Further, a first distance between the pre-processed measurement data and the healthy reference data is obtained and determined to exceed a first threshold for the first distance. A report is generated in response to determining that the first distance exceeds the first threshold. The report indicates detection of the anomaly in the measurement data.

Downhole tool analysis using anomaly detection of measurement data

A method for drilling a well includes applying a current across a drill collar that surrounds an internal magnetometer. The current travels across the drill collar and along one or more other current paths to return to the drill collar. The method also includes using the magnetometer to measure magnetic fields due to the current being applied across the drill collar and the current across one or more other current paths while the drill collar is disposed at a first angle of rotation and rotating the drill collar to a second angle of rotation. The method further includes measuring the magnetic fields using the internal magnetometer while the drill collar is disposed at the second angle of rotation and determining a relationship between the current across the drill collar and a portion of the magnetic fields due to the current across the drill collar measurable by the internal magnetometer.

Method for calibrating current and magnetic fields across a drill collar

The present invention discloses a diffusion edited pulse technique that allows information about a fluid to be extracted, comprising: a) obtaining a fluid sample; b) generating a sequence of magnetic field pulses in the fluid, the sequence comprising an initial magnetic field pulse, a first portion that follows the initial magnetic field pulse, and a second portion that follows the first portion; c) detecting magnetic resonance signals using the second portion of the sequence; d) modifying the first portion of the sequence, and repeating steps (b) and (c); and e) extracting information about the fluid by determining relaxation and diffusion characteristics and their correlation based on the signals detected in steps (c) and (d). Also disclosed is a logging tool equipped with a processor to implement the diffusion edited pulse technique.

Nuclear magnetic resonance method and logging apparatus for fluid analysis

NMR methods for extracting information about a fluid in rock and logging apparatuses for implementing such methods in a borehole environment are provided. The methods involve generating at least two different magnetic field pulse sequences. The magnetic field pulse sequences include a first portion and a second portion. A magnetic field pulse sequence is generated, and magnetic resonance signals are detected using the second portion of the sequence. The first portion of the sequence is modified, and again the sequence generated and magnetic resonance signals detected using the second portion. The magnetic resonance signals are analyzed, and information about, for example, diffusion coefficient, viscosity, composition, saturation in a rock, pore size, pore geometry and the like, extracted from the analyzed signals.

Nuclear magnetic resonance method and logging apparatus

Carbonate formations yield unreliable, down hole NMR results. Inter alia, these results must be corrected for temperature. The invention features several methods for obtaining more reliable NMR results for rock petrophysical parameters in carbonate rock formations based upon adjusting T.sub.2 data with respect to temperature.

Method for estimating rock petrophysical parameters using temperature

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Houston, TX, United States of America

Mark Flaum