Set retarded cement compositions, additives and methods
CA 2127346 C · Owner: Halliburton Company · Inventors: Rodrigues, Klein A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention provides set retarding additives sit retarded hydraulic cement compositions including such additives and methods of using the cement compositions for cementing zones in wells. The set retarding additives are copolymers or terpolymers containing monomer units formed from one of maleic acid, itaconic acid, fumaric acid citraconic, acid and mesaconic acid along with other monomer units.
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 July 4, 1994 and granted May 13, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 4, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 4, 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.
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.