An image focusing method and apparatus for wellbore resistivity imaging
CA 2397115 A1 · Owner: Evans, Martin T. · Inventors: Burt, Richard A.; Evans, Martin T.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An apparatus for obtaining resistivity images of a borehole includes an array of measure electrodes separated from a pad or the body of the instrument by a guard electrode. The guard electrode is maintained at a slightly lower potential than the pad and the measure electrode is at an intermediate potential thereto. With this arrangement the current from the guard electrode , defocuses the measure current from the measure electrode as it enters the formation, and at greater distances, the current from the measure electrode is refocused by the effect of the current from the pad. This defocusing and refocusing defines a region of investigation away from the borehole wall that is …
Read the whole patent
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 January 10, 2001. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended January 10, 2021.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 10, 2023.
- 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.