Patents by Inventor Johan F. G. van Velzen

Johan F. G. van Velzen 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).

  • Method of recovering hydrocarbons from an underground formation
    Patent number: 4643257
    Abstract: To prevent dissolution of siliceous grains or siliceous bonds between grains in or around a well when aqueous fluid is passed through the well in an oil recovery process, the siliceous solids are at least once treated with a solution of Co ions in a solvent such as water.
    Type: Grant
    Filed: April 15, 1985
    Date of Patent: February 17, 1987
    Assignee: Shell Oil Company
    Inventors: David L. Roberts, Johan F. G. van Velzen