Patents by Inventor Les Johnson

Les Johnson has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Shear-sensitive plugging fluid for plugging and a method for plugging a subterranean formation zone
    Patent number: 6815399
    Abstract: A plugging fluid for plugging a subterranean formation zone surrounding a drill hole consisting of an emulsion comprising an oil phase containing an oil, an emulsifier and 2.4 to 4 kg of cement per liter of oil and an aqueous phase containing water and 12-16 g of polysaccharide per liter of water, wherein the oil to water volume ratio ranges from 20:80 to 25:75. Upon shearing, the emulsion inverts so that the rupture of the emulsion droplets releases the cement into the water phase thus providing metallic divalent ion to crosslink with the polysaccharide and forming a gel structure.
    Type: Grant
    Filed: June 17, 2002
    Date of Patent: November 9, 2004
    Assignee: Schlumberger Technology Corporation
    Inventors: Les Johnson, Kamal Arsanious, David Quinn, Patrick Murphy, Allen R. Toney
  • Methods for high purity chromatographic separation of proteins having EGF-like binding domains
    Patent number: 5378816
    Abstract: Proteins having an epidermal growth factor-like binding region, such as thrombomodulin, may be recovered and purified on a anion exchange resin, such as a polyethyleneimine resin. Conditioned medium containing recombinantly produced protein is applied to the resin under conditions of pH and ionic strength selected to result in specific binding of the protein to the resin. The column is then washed to remove non-bound proteins and bound proteins other than the desired protein to be separated. The desired protein is then eluted from the column and collected in a medium. Further purification, concentration, and other treatment of the protein may be performed by conventional techniques.
    Type: Grant
    Filed: December 16, 1992
    Date of Patent: January 3, 1995
    Assignee: Berlex Laboratories, Inc.
    Inventors: Erno Pungor, Les Johnson, Monica R. Foermer
  • Method of cementing well casing to avoid gas channelling from shallow gas-bearing formations
    Patent number: 5199489
    Abstract: Gas channeling to the surface in the setting of surface casing can be avoided by employing a cementing process in which a right-angle setting cement is positioned within a wellbore annulus between the wellbore and the casing above a gas-bearing zone with a low fluid loss cement slurry being placed below the right-angle setting cement. Pumping of the cement slurry is stopped for a period of time to allow the setting of the right-angle setting cement at which point pressurized pumping is resumed to displace remaining portions of the low fluid loss cement slurry into the wellbore annulus against the plug created by the set right-angle setting cement to block off gas migration and squeeze the low fluid loss cement into the gas-bearing zone.
    Type: Grant
    Filed: November 30, 1990
    Date of Patent: April 6, 1993
    Assignee: Dowell Schlumberger Incorporated
    Inventors: Les Johnson, Brian Sissons, Kerry Crapo