The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 09, 1996
Filed:
Jan. 10, 1995
Jerry L Brady, Anchorage, AK (US);
Stephen Gerlek, Anchorage, AK (US);
David L Lagerlef, Eagle River, AK (US);
Raymond Wydrinski, Lewisville, TX (US);
Atlantic Richfield Company, Los Angeles, CA (US);
Abstract
Corrosion in well tubing strings, pipe and similar conduits may be determined by a circuit which includes a current sensitive meter and a known voltage source which is placed at selected intervals in the tubing string to make current flow measurements and voltage drop measurements between spaced apart contactors engaged with the tubing string at the selected intervals. The current flow measurements from the known source are used to determine resistance of the measured interval and voltage drop from a second source imposed on the tubing string at the surface is measured at the selected intervals to determine current flow from the second source. The differences in current flow at the selected intervals at a first measurement are compared with the differences in current flow at the same intervals at a later time to indicate any changes in current flow which may be related to corrosion in the tubing string between the intervals of measurement. The circuits may be placed in gas lift valve assemblies at spaced apart gas lift mandrels in the tubing string and signals related to current flow and voltage transmitted to the surface by stress wave telemetry or electromagnetic waves transmitted through the earth, for example. The circuits may also be interposed in selected sections of tubing spaced apart in the tubing string or on an instrument carrier apparatus which may be selectively positioned in the tubing string by a coiled tubing conveyed or wire line conveyed running tool.