Claims
- 1. Flow pulsing apparatus for a drill string, the apparatus comprising:a housing for location in a drill string above a drill bit, the housing defining a throughbore to permit passage of drilling fluid therethrough; a valve located in the bore and including first and second valve members each defining a respective axial flow opening and which openings are aligned to collectively define an open axial drilling fluid flow port through the valve, the first member being rotatable about a longitudinal axis of the housing to vary the alignment of the openings between a first alignment in which the openings collectively define an open axial flow port of a first open area and a second alignment in which the openings collectively define an open axial flow port of a second open area greater than said first open area to, in use, provide a varying flow therethrough and variation of the drilling fluid pressure; and drive means operatively associated with the valve for rotating the first member.
- 2. The apparatus of claim 1 wherein the axis of rotation of the first valve member is offset from the second member such that rotation of the first member moves the openings out of alignment.
- 3. The apparatus of claim 2 wherein the valve openings are in the form of transverse slots on a common axis.
- 4. The apparatus of claim 1 wherein the valve openings are non-circular.
- 5. Flow pulsing apparatus for drill string, the apparatus comprising:a housing for location in a drill string above a drill bit, the housing defining a throughbore to permit passage of drilling fluid therethrough; a valve located in the bore and including first and second valve members each defining a respective axial flow opening and which openings are aligned to collectively define an open axial drilling fluid flow port through the valve, the valve member openings being of similar shape such that when the openings are aligned the maximum flow area of the axial flow port corresponds to the area of each opening, the first member being rotatable about a longitudinal axis offset from a longitudinal axis of the second member such that rotation of the first member moves the openings between a first alignment in which the openings collectively define an open axial flow port of a first open area and a second alignment in which the openings collectively define an open axial flow port of a second open area greater than said first open area to, in use, provide a varying flow therethrough and variation of the drilling fluid pressure; and drive means operatively associated with the valve for rotating the first member.
- 6. Downhole apparatus comprising:a housing for location in a tubing string, the housing defining a throughbore to permit passage of fluid therethrough; a valve located in the throughbore and defining a flow passage and including a valve member, the valve member being transversely movable to vary the area of the flow passage to, in use, provide a varying fluid flow therethrough; and a fluid actuated positive displacement motor having a rotor coupled to the valve member for communicating transverse movement of the rotor to the valve member.
- 7. Downhole apparatus comprising:a housing for location in a tubing string, the housing defining a throughbore to permit passage of fluid therethrough; a device including a member which is transversely movable relative to an axis of the housing; and a fluid actuated positive displacement motor having a rotor coupled to the member for communicating transverse movement of the rotor to the member.
- 8. A flow pulsing drilling method comprising the steps:providing a valve in a drill string bore including first and second valve members each defining a respective axial flow opening and which openings collectively define an open axial flow port through the valve, the first member being rotatable about a longitudinal axis of the housing to vary the alignment of the openings, the openings being arranged such that in a complete rotation of the first member about said longitudinal axis the openings are always at least partially aligned and the axial flow port varies in area between a minimum first open area when the first member is positioned in a first alignment and a maximum second open area when the first member is positioned in a second alignment; and rotating the first member about said longitudinal axis to vary the alignment of the openings between said first alignment and said second alignment to provide variable flow therethrough and thus produce varying fluid pressure in the drilling fluid.
Priority Claims (2)
Number |
Date |
Country |
Kind |
9610451 |
May 1996 |
GB |
|
9625096 |
Dec 1996 |
GB |
|
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of U.S. application Ser. No. 09/194,003, filed Nov. 18, 1998, now U.S. Pat. No. 6,279,670, and PCT/GB97/01343 of May 16, 1997, priority of which is GB9610451.8 of May 18, 1996, which is hereby incorporated herein in its entirety by reference.
US Referenced Citations (9)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0 335 543 |
Oct 1989 |
EP |
2 059 481 |
Apr 1981 |
GB |
Continuations (1)
|
Number |
Date |
Country |
Parent |
PCT/GB97/01343 |
May 1997 |
US |
Child |
09/194003 |
|
US |