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Expired Canadian patentCanada

Process for cementing casing in a well

CA 1070236 A · Owner: Standard Oil Company · Inventors: Holman, George B.; Powers, Charles A.; Smith, Robert C.

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

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Abstract From the Canadian patent

A process for reducing the waiting-on-cement (WOC) time associated with the cementing of a casing string in an oil well involving the specific improvement of pumping into the well a highly retarded cement slurry containing a dispersed encapsulated accelerator such as calcium, chloride or anhydrous sodium metasilicate wherein the encapsulating, material is specifically selected such that it will melt at a temperature above the bottom-hole circulating temperature but below the bottomhole static temperature of the well to be cemented. Petroleum-derived waxes and petroleum-derived waxes in combination with vinyl resins such, as wax-compatible copolymers of ethylene and vinyl acetate are …

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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

  • Granted January 22, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 22, 1997.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Filed—
GrantedJanuary 22, 1980
Term endedJanuary 22, 1997
Patent numberCA 1070236 A
Classification (IPC)E21B33/14

Timeline

Timeline From CIPO dates

198119831985198719891991199319951997Patent grantedJan 22, 1980Term endedJan 22, 1997

Sources & verification

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