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Expired Canadian patentCanada

Low-water-pressure controlled hydrologic test method

CA 1331840 C · Owner: Taisei Kiso Sekkei Co. Ltd. · Inventors: Hirata, Yoichi; Yanagisawa, Koichi

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Abstract From the Canadian patent

A low-water-pressure-controlled hydrologic test using a measurement pipe containing an inner packer which is equipped with a water pressure gage at its tip is disclosed. Some water is poured into the measurement pipe in advance so as to diminish the pressure head difference between the in-pipe pressure and the pore water pressure of the rock concerned. The permeability coefficient is obtained by measuring changes in the recovered water level in terms of pressure changes. In the case of an aquiclude, the inner pressure is raised by expanding the inner packer, the permeability coefficient being obtained by detecting the changes in inner pressure. Thus the method allows a permeability test to …

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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 September 6, 1994. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 6, 2011.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJune 5, 1989
GrantedSeptember 6, 1994
Term endedSeptember 6, 2011
Patent numberCA 1331840 C
Classification (IPC)E21B49/08 +2 more

Timeline

Timeline From CIPO dates

19901993199619992002200520082011Application filedJune 5, 1989Patent grantedSep 6, 1994Term endedSep 6, 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.