Turbine for power generation in a drill string

• US 20090104021A1
• Filed: 09/09/2008
• Published: 04/23/2009
• Est. Priority Date: 10/17/2007
• Status: Active Grant

• Current Assignee: Weatherford Energy Services GmbH (Becfield Drilling Services (BVI) Ltd.)
• Original Assignee: Weatherford Energy Services GmbH (Becfield Drilling Services (BVI) Ltd.)
• Inventors: Winnacker, Helmut, Draeger, Uwe
• Granted Patent: US 8,092,147 B2
• Time in Patent Office: Days
• US Class Current: 415/145
• CPC Class Codes: E21B 21/103 Down-hole by-pass valve arrangements, i.e. between the inside of the drill string and the annulus valves specifically for maintaining circulation of drilling fluid while connecting or disconnecting tubular joints E21B21/019
• CPC Class Codes: E21B 41/0085 Adaptations of electric power generating means for use in boreholes
• CPC Class Codes: F03B 13/02 Adaptations for drilling wells
• CPC Class Codes: Y10S 415/903 Well bit drive turbine
• CPC Class Codes: Y10S 415/904 Tool drive turbine, e.g. dental drill

Abstract

The invention is directed to a turbine (3) for generating power in a drill string (2), including a turbine rotor (10) drivable by a fluid and a bypass device having a first bypass channel bypassing the turbine rotor (10). For varying the volumetric flow through the bypass channel, provision is made for a valve (28) and a control device driven by the fluid and having a drive element (24) by means of which the valve (28) is movable anywhere between a first and a second position. The drive element (24) produces a flow resistance in the fluid flow path downstream from the turbine rotor (10) and downstream from the valve (28) and in the flow direction takes support upon a spring (26).

Claims

1. A turbine for generating power in a drill string, with a turbine rotor drivable by a fluid, and a bypass device having a first bypass channel bypassing the turbine rotor, a valve for varying the volumetric flow through the bypass channel, and a control device which is driven by the fluid and has a drive element by means of which the valve is movable anywhere between a first and a second position, wherein said drive element produces a flow resistance in the fluid flow path downstream from the turbine rotor and downstream from the valve and in the flow direction takes support upon a spring.

2. The turbine according to claim 1, wherein the first bypass channel opens into a turbine compartment on the outlet side of the turbine rotor.

3. The turbine according to claim 1, further comprising a cylindrical housing having a first housing section of larger diameter and a second housing section of smaller diameter, said housing sections being separated from each other by a housing shoulder.

4. The turbine according to claim 3, wherein the housing section of larger diameter has on its outer side guide ribs which are arranged at a circumferential distance from each other and form a guide for the housing in the drill string.

5. The turbine according to claim 3, wherein the housing section carries a guide ring with sector-shaped openings for passage of the fluid, said openings being separated from each other by radial bars.

6. The turbine according to claim 4, wherein the turbine rotor is arranged in a turbine compartment of the housing section of larger diameter, said turbine compartment being connected upstream from the guide ribs by radial inlet openings and downstream from the guide ribs by outlet openings to an annular chamber formed between the housing and the drill string.

7. The turbine according to claim 6, wherein the outlet openings are provided in the housing shoulder.

8. The turbine according to claim 1, wherein the turbine rotor is arranged in a turbine compartment of a housing and the valve has several valve openings which are evenly distributed over the circumference of a housing section, and wherein a sleeve-shaped closure element which is associated with said valve openings, surrounds the housing section and is guided thereon in a sliding relationship.

9. The turbine according to claim 8, wherein in the open position the valve openings connect an annular chamber formed between the housing and the drill string to a section of the turbine compartment lying on the outlet side of the turbine rotor.

10. The turbine according to claim 8, wherein the valve openings have a cross-section which extends in the axial direction and has a maximum width in the circumferential direction at the forward end of the valve openings as seen looking in the direction of flow, and decreases continuously with increasing distance from said end.

11. The turbine according to claim 8, wherein the closure element is connected via axially extending bars spaced at a uniform circumferential distance from each other to a sleeve-shaped drive element which is guided on a housing section of smaller diameter in a sliding relationship.

12. The turbine according to claim 8, wherein the drive element has on its side close to the closure element a radially extending end face to which the volumetric flow escaping from the closure element is applied.

13. The turbine according to claim 3, wherein the spring is a compression spring which is seated on the housing section of smaller diameter of the housing between the drive element and a stop formed fast with the housing.

14. The turbine according to claim 1, wherein the bypass device includes a second bypass channel bypassing the turbine rotor and the valve, wherein the volumetric flow through the second bypass channel is variable by means of an adjustable throttling device.

15. The turbine according to claim 14, wherein the adjustable throttling device includes a throttling element which is movable by the drive element of the control device.

16. The turbine according to claim 15, wherein at least one throttling element has the shape of a pointed arrow whose tip is directed against the flow.

17. The turbine according to claim 8, wherein a bypass sleeve surrounding with radial clearance the closure element is fastened to the housing, and between the bypass sleeve and the closure element provision is made for a free annular chamber which forms a second bypass channel.

18. The turbine according to claim 17, wherein the bypass sleeve has an inner wall whose inner diameter is smallest at the afflux end and increases toward the other end, such that the flow cross-section of the annular chamber grows larger in the flow direction.

19. The turbine according to claim 17, wherein on the outer circumferential surface of the closure element provision is made for several throttling elements which constrict the flow cross-section between the bypass sleeve and the closure element wherein the volumetric flow through the second bypass channel is variable by axial movement of the bypass sleeve.

20. The turbine according to claim 19, wherein at least one throttling element has the shape of a pointed arrow whose tip is directed against the flow.

21. The turbine according to claim 19, wherein the throttling elements are arranged in spaced relationship in the circumferential direction and form between them channel-like passageways for the passage of the fluid.