Magnetic field enhancement for use in passive ranging
CA 2460788 C · Owner: Smith International, Inc. · Inventors: Mcelhinney, Graham A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method for surveying a borehole is provided. The method includes providing a casing string having a plurality of opposing magnetic poles in a target borehole. The method also includes providing a tool having a magnetic field measurement device disposed thereon and positioning the tool in another borehole. Magnetic interference vectors are determined in the other borehole by comparing the measured magnetic field at that position with a known magnetic field of the earth. The magnetic interference vector indicates a direction to a casing string. Various embodiments of the invention may be utilized to drill one borehole along a predetermined course relative to another borehole. The surveying …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed March 12, 2004 and granted September 24, 2013. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 12, 2024.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 12, 2026.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.