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Expired Canadian patentCanada

Identifying earth stresses in acoustic well logging

CA 2034263 C · Owner: Medlin, William Louis · Inventors: Medlin, William Louis

CIPO record

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

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Abstract From the Canadian patent

An acoustic logging tool traverses a fluid-filled cased well with a monopole acoustic energy source. Pressure waves in the well fluid by the source generate symmetric tube waves in the well casing immediately adjacent the source. At least one spaced-apart receiver detects these tube waves after they have traveled directly to the receiver through the well casing. Asymmetry imparted to said tube waves as they travel along the well casing by the maximum and minimum earth stresses behind the well casing are identified and used to predict the azimuthal direction of subsequent hydraulic fractures.

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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

  • Filed January 16, 1991 and granted August 18, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 16, 2011.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 16, 2013.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJanuary 16, 1991
GrantedAugust 18, 1998
Term endedJanuary 16, 2011
Patent numberCA 2034263 C
Classification (IPC)G01V1/44 +1 more

Timeline

Timeline From CIPO dates

1992199419961998200020022004200620082010Application filedJan 16, 1991Patent grantedAug 18, 1998Term endedJan 16, 2011

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