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Expired Canadian patentCanada

Controlling ferric ions while acidizing subterranean formations

CA 2136395 C · Owner: Plainsman Technology, Inc. · Inventors: Vinson, Edward F.

CIPO record

Overview

Drawings and full text

Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

A composition for and method of treating a subterranean hydrocarbon producing formation is provided. The treatment, when conducted in the presence of ferric ions, prevents the development of insoluble ferric iron-containing compounds and also prevents the development of sludge in heavy crude.

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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 November 22, 1994 and granted August 19, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 22, 2014.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 22, 2016.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledNovember 22, 1994
GrantedAugust 19, 1997
Term endedNovember 22, 2014
Patent numberCA 2136395 C
Classification (IPC)E21B43/25 +2 more

Timeline

Timeline From CIPO dates

1995199719992001200320052007200920112013Application filedNov 22, 1994Patent grantedAug 19, 1997Term endedNov 22, 2014

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.