Baker Hughes Corporation

Ico, Inc.

National Oilwell Varco, L.p.

Clive C Lam

Kevin D Logan

Yanming Guo

Qingshan Yuan

Roy C Grubbs

William W Curtis, Jr

Andres C Rodriguez

Claudio Aguirre

A plurality of magnetic field members are provided, each for selectively generating a time-varying magnetic field for combination into a o time-varying composite longitudinal magnetic field with magnetic flux lines which are substantially aligned with the central longitudinal axis of the cylindrical ferromagnetic member. Additionally, a traverse magnetic field member is provided which selectively generates a time-varying traverse magnetic field with magnetic flux lines which are substantially traversed to the central longitudinal axis of the cylindrical ferromagnetic member. The plurality of magnetic field members and the traverse magnetic field member are maintained out of contact with the cylindrical ferromagnetic member. Magnetic particles are placed on selected portions of the cylindrical ferromagnetic member. A time-varying composite longitudinal magnetic field and a time-varying traverse magnetic field are applied to the cylindrical magnetic member, while it is being rotated. An operator inspects the outer and/or inner peripheral surfaces of the cylindrical member to detect defects therein from accumulations in magnetic particles at leakage fields corresponding to magnetic discontinuities of defects in the cylindrical ferromagnetic member.

Method and apparatus for noncontact magnetic particle stray magnetic

A method and apparatus for determining the extent of defects in tubular elements for use in an oil or gas well is disclosed. The apparatus includes an electromagnetic or other suitable inspection device, cooperating with longitudinal and circumferential position detectors for determining the position and configuration of all defects within a tubular member. Signal generating means are provided for producing signals corresponding to the configuration, longitudinal position, and circumferential position of the defects located within the wall of the tubular member. The signals are processed, preferably by a computer, so that the presence, nature, and precise location of each defect is determined and visually displayed at a suitable display means. Display means are provided for generating a two-dimensional visual display wherein the circumferential and longitudinal positions of the defects are selectably displayed.

Method and apparatus for detecting angular defects in a tubular member

Method and apparatus for displaying defects in tubular members on a

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Tomball, TX, United States of America

Clive C Lam