Downhole flexible drive system
Dual-rotating eccentric drilling apparatus and method Patent #: 4267893
ApplicationNo. 06/518270 filed on 07/28/1983
US Classes:175/61, Boring curved or redirected bores175/107, Fluid rotary type175/320WITH TOOL SHAFT DETAIL
ExaminersPrimary: Novosad, Stephen J.
Assistant: Starinsky, Michael
International ClassesE21B 4/02 (20060101)
E21B 4/20 (20060101)
E21B 7/04 (20060101)
E21B 7/06 (20060101)
E21B 4/00 (20060101)
Foreign Application Priority Data1982-08-25 GB
AbstractThe invention relates to a downhole motor having a housing of which the resistance against bending in a predetermined longitudinal plane is smaller than in any other longitudinal plane. Directional drilling of boreholes is carried out by rotating the drill string simultaneously with the rotation of the drill bit driven by the downhole motor over periods preceded and followed by selected periods during which the drill string is not rotated simultaneously with the rotation of the drill bit driven by the downhole motor.