Elimination of the influence of drill string magnetisation on borehole azimuth measurement

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Listed from its IP Australia record in Patent Yard's archive of Australian patents past their term. Its claims, description and drawings are in the AusPat record and on Google Patents, and the Claude kit works from them.

Why it's free to use

• Filed February 24, 1986 and granted August 8, 1988. An Australian standard patent lasts 20 years from its date of patent, which is at most a year after this filing, so its term ended by February 24, 2007.
• A pharmaceutical extension adds at most five years, so even that would have ended by February 24, 2012.
• We check Australian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.