Patents by Inventor Fred G. Helfferich

Fred G. Helfferich 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).

  • Ion exchange controlled chemically aided waterflood process
    Patent number: 4074755
    Abstract: A process for recovering oil by successively injecting at least a chemical slug containing an active aqueous surfactant system or thickened aqueous liquid and an aqueous drive liquid into a reservoir having a significant amount of ion exchange capacity, is improved. The ionic composition of each injected fluid is arranged to provide a ratio, between the concentration of its effectively predominate monovalent cation and the square root of the concentration of its effectively predominate divalent cation, which ratio at least substantially equals such a ratio within the aqueous fluid immediately ahead of the injected fluid.
    Type: Grant
    Filed: March 21, 1977
    Date of Patent: February 21, 1978
    Assignee: Shell Oil Company
    Inventors: Harold J. Hill, Joseph Reisberg, Fred G. Helfferich, Larry W. Lake, Gary A. Pope