Patents by Inventor Virgil H. Barfield

Virgil H. Barfield 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 and apparatus for controlling borehole pressure in perforating wells
    Patent number: 4605074
    Abstract: A method and apparatus for controlling pressure in a borehole during perforation to provide means for maintaining a fluid column above the perforating zone to control a blowout while isolating the perforating zone from such fluid column to prevent incursion of the fluid column into the perforated zone immediately upon perforation. Provision is also made for a low pressure zone for inducing flow from the formation into the wellbore immediately upon perforation.
    Type: Grant
    Filed: October 15, 1984
    Date of Patent: August 12, 1986
    Inventor: Virgil H. Barfield