Patents Assigned to Tecmark International
  • Multiple drain method for recovering oil from tar sand
    Patent number: 6263965
    Abstract: A thermal method is described for recovering normally immobile hydrocarbon oil from a subsurface tar sand deposit.
    Type: Grant
    Filed: April 13, 1999
    Date of Patent: July 24, 2001
    Assignee: Tecmark International
    Inventors: Brian H. Schmidt, Paul J. Jespersen, Brian J. Kristoff