Method of maintaining subterranean formation permeability and inhibiting clay swelling
CA 2106778 C · Owner: Thomas, Todd R. · Inventors: Thomas, Todd R.; Smith, Kevin W.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Swelling and migration of subterranean clay is inhibited during stimulation of the production of hydrocarbon fluids and, preparation therefor, by treating said formations with a compound of the formula (CH2=CH-CH2)nN+(CH3)4nX- where X may be any anion which does not adversely react with the formation or treatment fluid and n is an integer from 1 to 4.
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 February 9, 1993 and granted March 18, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 9, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 9, 2015.
- 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.