Patents by Inventor David A. Krol

David A. Krol 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 freeing stuck drill string using spotting fluid
    Patent number: 4491181
    Abstract: A spotting fluid comprising an oily material containing a solid spotting agent, said solid spotting agent comprising at least 20 weight percent of said oily material and at least 32 pounds per barrel of said solid spotting agent, said solid spotting agent comprising substantially spherical particles having a specific gravity of at least 2.0, an average particle diameter below 212 microns, and a compressive strength of at least 5000 psi is used to free a differentially stuck drill string.
    Type: Grant
    Filed: March 31, 1983
    Date of Patent: January 1, 1985
    Assignee: Gulf Research and Development Co.
    Inventor: David A. Krol