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Proceedings Paper

Analysis and optimization of NMR sensor for oilfield exploration applications
Author(s): Jaideva C. Goswami; Bruno Luong
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Paper Abstract

Nuclear magnetic resonance (NMR) measurements have become an important part of oilfield well-logging to identify and quantify oil and gas reservoirs. In this paper, some design aspects of NMR sensor for well-logging applications are discussed. The RF and static magnetic fields are computed using a 3D finite element method (FEM). A perturbation technique along with FEM is used to evaluate the power loss in conductors that avoids the need for small discretization steps along the conductor thickness. The magnet is built by stacking several magnet segments along the axial direction and the objective is to magnetize and shape these segments in such a way so as to produce a desired field profile in front of the magnet. An optimal control technique is used in conjunction with the FEM to speed up the design process with signal-to-noise ratio, frequency of operations, depth of investigation, and prepolarization time being the optimization constraints. Very good agreement between the measured and computed antenna efficiency and magnetic field is obtained thus validating the numerical model.

Paper Details

Date Published: 6 July 2000
PDF: 5 pages
Proc. SPIE 4129, Subsurface Sensing Technologies and Applications II, (6 July 2000); doi: 10.1117/12.390616
Show Author Affiliations
Jaideva C. Goswami, Schlumberger Oilfield Services (United States)
Bruno Luong, Schlumberger Oilfield Services (United States)

Published in SPIE Proceedings Vol. 4129:
Subsurface Sensing Technologies and Applications II
Cam Nguyen, Editor(s)

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