Patents Assigned to Easfind Limited
  • Cementing apparatus and methods
    Patent number: 4664192
    Abstract: In drilling a well, sections of casing are run down a borehole, preferably with a float shoe at the lower end which is equipped with a double valve enabling the casing to fill with drilling mud both while the casing is moving down and also while it is stationary. Within the casing is a baffle collar which defines a socket for a latching dart carried by a plug. The plug and dart are driven down to the collar, when the pumping of cement into the casing has been completed, by a launching dart which also closes the passageway through the plug.
    Type: Grant
    Filed: October 9, 1984
    Date of Patent: May 12, 1987
    Assignee: Easfind Limited
    Inventor: Peter J. M. Hogarth