Patent EA-000788-B1 (EA)
Title: Downhole clutch with flow ports
Inventor: BEST BRUNO
IPC: E21B17/06
Filed: 1998-02-24
Abstract: 1. A method of operating the drill string tool (1) in a wellbore in an earth formation comprising a first element (1a) being connected to an upper drill string part (3), a second element (5) being connected to a lower drill string part (7), bearing means (11) allowing rotation of the first element relative to the second element about the longitudinal axis of the drill string, rotation transfer means (15) for transferring rotation of the first element about the longitudinal axis to the second element, and control means for selectively disengaging said rotation wherein the method comprising the steps of: a) rotating the upper drill string part (3) while the rotation transfer means transfers the rotation of the first element (1a) to the second element (5) so as to rotate the lower drill string part (7) in order to drill a section of said wellbore; b) inducing the control means (26, 28)to disengage the rotation transfer means (15) so as to allow the first element (1a) to rotate relative to the second element by virtue of the bearing means (11); and c) rotating the upper drill string part (3) about its longitudinal axis while the lower drill string part (7) remains substantially stationary and d) during step c) a longitudinal force is applied to the upper drill string part so as to release the lower drill string part from the well bore. 2. The method of operating the drill string tool(1) in a wellbore in an earth formation comprising a first element (1a) being connected to an upper drill string part (3), a second element (5) being connected to a lower drill string part (7), bearing means (11) allowing rotation of the first element relative to the second element about the longitudinal axis of the drill string, rotation transfer means (15) for transferring rotation of the first element about the longitudinal axis to the second element, and control means for selectively disengaging said rotation wherein the method comprising the steps of:a) rotating the upper drill string part (3) while the rotation transfer means transfers the rotation of the first element (1a) to the second element (5) so as to rotate the lower drill string part (7) in order to drill a section of said wellbore; b) inducing the control means (26, 28)to disengage the rotation transfer means (15) so as to allow the first element (1a) to rotate relative to the second element by virtue of the bearing means (11); and c) rotating the upper drill string part (3) about its longitudinal axis while the lower drill string part (7) remains substantially stationary and d) during or after step c) wellbore fluid flows through the wellbore so as to clean the wellbore from drill cuttings. 3. The method of claim 2, wherein the rotational speed of the upper drill string part (3) during step c) is selected so as to induce a lateral vibration of the upper drill string part in the wellbore. 4. The method claims 2 or 3, wherein the upper drill string part (3) during step c) is induced to take a helical shape in the wellbore 5. The method of any one of claims 1-4, wherein said rotation transfer means comprises a clutch. (15). 6. The method of any one of claims 1-5, wherein said control means comprises an object which is movable through the drill string to the tool. 7. The method of any one of claims 1-5, wherein the drill string includes a jarring apparatus. 8. The method of claim 7, wherein the tool and the jarring apparatus are integrally formed. 9. The method of claim 6 or 7, wherein the jarring apparatus is located in the lower drill string part.