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Expired Canadian patentCanada

Apparatus and method for combined acoustic and seismoelectric logging measurements

CA 2235263 C · Owner: Strack, Kurt-Martin · Inventors: Tang, Xiaoming; Cheng, Arthur Chuen Hon; Yu, Gang

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Abstract From the Canadian patent

A method for estimating porosity of an earth formation from measurements of acoustic energy traversing the earth formation and from measurements of seismoelectric voltages generated in the formation in response to the acoustic energy. The method includes the steps of measuring the acoustic energy traversing the earth formation and measuring said seismoelectric voltages generated in response to the acoustic energy traversing the formation. A seismoelectric signal is synthesized from the measurements of the acoustic energy using an initial value of the porosity. A difference is determined between the synthesized seismoelectric voltages and the measured seismoelectric voltages. The initial …

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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 April 21, 1998 and granted April 8, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 21, 2018.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 21, 2020.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledApril 21, 1998
GrantedApril 8, 2003
Term endedApril 21, 2018
Patent numberCA 2235263 C
Classification (IPC)G01V11/00 +1 more

Timeline

Timeline From CIPO dates

1999200120032005200720092011201320152017Application filedApril 21, 1998Patent grantedApril 8, 2003Term endedApril 21, 2018

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