Patents Assigned to Drilex UK Limited and Eastman Christensen Company
  • Patent number: 4807708
    Abstract: A method of controlling the direction of a drill bit (3) at the downhole end of a drill string (2) drilling from a surface comprises providing two steerable stabilizers (4, 5) at the downhole end of the drill string (2) at locations spaced apart in the drilling direction and adjusting the orientation of the stabilizers to create reactive forces from the bore hole (6) to deflect the course of the bit (3) in a desired direction. The stabilizers (4, 5) are suitably arranged eccentrically and circumferentially offset by 180.degree..+-.60.degree.. In normal drilling the drill string (2) is rotated such that stabilizers (4, 5) engage the bore hole (6) to support a downhole motor (1) against tilting. When off course drilling is sensed the stabilizers are rotated to a position and stopped from rotation such that drilling forces generate reaction forces to cause a desired change of direction.
    Type: Grant
    Filed: October 1, 1986
    Date of Patent: February 28, 1989
    Assignee: Drilex UK Limited and Eastman Christensen Company
    Inventors: John Forrest, Roger Catherall, William Stewart, Randall J. Pounds