Drilling a borehole
CA 1096154 A · Owner: Shell Canada Limited · Inventors: Van Laar, Hermanus G.; Lagrand, Johannes
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The cost of drilling a water sensitive shale is reduced by first enhancing drilling rate by circulating a clear drilling fluid, then avoiding borehole instability due to shale-water interaction by circulating an aqueous solution of 10-20% hydrolyzed polyacrylamide and alkali metal halide. Borehole instability due to mechanical incompetence of earth formations may be avoided by circulating a suspension of pre-hydrated bentonite in the said solution to enhance the borehole cleaning while continuing the shale stabilization.
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
- Granted February 24, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 24, 1998.
- 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.