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Expired Canadian patentCanada

Stimulation of earth formations surrounding a deviated wellbore by sequential hydraulic fracturing

CA 1267361 C · Owner: Uhri, Duane Christian · Inventors: Uhri, Duane Christian

CIPO record

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Abstract From the Canadian patent

A subsurface formation surrounding a deviated borehole and having original in-situ stresses that favor the propagation of a vertical fracture is penetrated by a cased borehole. The casing is perforated at a pair of spaced-apart intervals to form a pair of sets of perforations. Fracturing fluid is initially pumped down said cased borehole and out one of said sets of perforations to form a first fracture that is oriented in a direction perpendicular to the direction of the least principal in-situ horizontal stress. The propagation of this first vertical fracture changes the in-situ stresses so as to favor the propagation of a second vertical fracture. This is oriented in a direction parallel …

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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 April 3, 1990. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 3, 2007.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledAugust 14, 1987
GrantedApril 3, 1990
Term endedApril 3, 2007
Patent numberCA 1267361 C
Classification (IPC)E21B43/26 +1 more

Timeline

Timeline From CIPO dates

1988199019921994199619982000200220042006Application filedAug 14, 1987Patent grantedApril 3, 1990Term endedApril 3, 2007

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