Downhole tubular connector

1. A hydraulic connector to provide a fluidic connection between a fluid supply and a downhole tubular, the connector comprising:

a body;

an engagement assembly comprising an extendable portion selectively extendable from the body, the engagement assembly being configured to extend and retract a seal assembly disposed at a distal end of the extendable portion into and from a proximal end of the downhole tubular; and

a valve assembly operable between an open position and a closed position, the valve assembly being configured to: allow a fluid to communicate between the fluid supply and the downhole tubular through the seal assembly when in the open position; and prevent fluid communication between the fluid supply and the downhole tubular when in the closed position,

wherein the extendable portion comprises a first abutment surface disposed to limit the extension of the engagement assembly by contact of the first abutment surface with a corresponding abutment surface of the body,

wherein the engagement assembly comprises a piston disposed about the extendable portion and divides a cylinder defined by the body portion into a first chamber and a second chamber, and

wherein the piston comprises a third chamber and one or more passages, the one or more passages fluidicly connecting the third chamber to the first chamber.

2. The hydraulic connector of claim 1 , wherein the first chamber contains pressurised fluid to retract the extendable portion.

3. The hydraulic connector of claim 1 , wherein the first chamber is sealed to define a substantially closed system.

4. The hydraulic connector of claim 1 , wherein the first chamber comprises a valve connectable to a source of pressurised fluid, the valve permitting the first chamber to be charged and/or recharged with pressurised fluid.

5. The hydraulic connector of claim 1 , wherein the second chamber is in communication with drilling mud to extend the seal assembly.

6. The hydraulic connector of claim 1 , wherein the extendable portion comprises a cap, the piston being configured to be displaced away from the cap when the valve assembly is in the open position.

7. The hydraulic connector of claim 1 , wherein the extendable portion comprises a through bore extending between the piston and the seal assembly to allow the fluid to communicate between the fluid supply and the downhole tubular.

8. The hydraulic connector of claim 1 , wherein the piston is slidably disposed between a cap and the second abutment surface provided on the extendable portion.

9. The hydraulic connector of claim 8 , wherein the extendable portion comprises an annulet, the annulet forming the first and second abutment surfaces.

10. The hydraulic connector of claim 1 , wherein the engagement assembly is configured to extend the seal assembly when a pressure of fluids in the fluid supply exceed a threshold value.

11. The hydraulic connector of claim 1 , wherein the extendable portion comprises a second abutment surface disposed to limit the travel of a piston.

12. The hydraulic connector of claim 1 , wherein the body comprises a threaded portion disposed at a distal end of the body, the threaded portion being configured to threadably engage a threaded section in the proximal end of the downhole tubular.

13. The hydraulic connector of claim 12 , wherein the threaded portion threadably engages the downhole tubular inside a box threaded end of the downhole tubular.

14. The hydraulic connector of claim 1 , wherein the seal assembly is configured to seal against a bore of the downhole tubular beyond a threaded section in the proximal end of the downhole tubular.

15. The hydraulic connector of claim 1 , wherein the fluid supply comprises a top-drive assembly.

16. A hydraulic connector to provide a fluidic connection between a fluid supply and a downhole tubular, the connector comprising:

a body;

an engagement assembly comprising an extendable portion selectively extendable from the body, the engagement assembly being configured to extend and retract a seal assembly disposed at a distal end of the extendable portion into and from a proximal end of the downhole tubular; and

a valve assembly operable between an open position and a closed position, the valve assembly being configured to: allow a fluid to communicate between the fluid supply and the downhole tubular through the seal assembly when in the open position; and prevent fluid communication between the fluid supply and the downhole tubular when in the closed position,

wherein the extendable portion comprises a first abutment surface disposed to limit the extension of the engagement assembly by contact of the first abutment surface with a corresponding abutment surface of the body, and

wherein the seal assembly is retractable within the distal end of the body.

17. A method of providing a fluidic connection between a fluid supply and a downhole tubular using a hydraulic connector, the method comprising:

providing the hydraulic connector with a body, a valve assembly, a seal assembly and an engagement assembly, the engagement assembly comprising an extendable portion with the seal assembly disposed upon a distal end of the extendable portion;

extending the extendable portion until a first abutment surface disposed on the extendable portion abuts a corresponding abutment surface of the body;

engaging the seal assembly within a proximal end of the downhole tubular;

opening the valve assembly;

hydraulically communicating fluid between the fluid supply and the downhole tubular; and

retracting the seal assembly within the distal end of the body.

18. The method of claim 17 , further comprising:

providing the engagement assembly with a piston disposed about the extendable portion and configured to divide a cylinder defined by the body portion into a first chamber and a second chamber;

sealing the first chamber such that it defines a substantially closed system; and

providing the first chamber with pressurised fluid to resist extension of the extendable portion.

19. The method of claim 18 , further comprising:

allowing the pressurised fluid in the first chamber to expand against the piston to retract the extendable portion.

20. The method of claim 18 , further comprising:

charging and/or recharging the first chamber with pressurised fluid.

21. The method of claim 17 , further comprising:

reducing the pressure of fluids in the fluid supply;

closing the valve assembly; and

retracting the seal assembly from the proximal end of the downhole tubular.

22. The method of claim 17 , further comprising:

providing the extendable portion with a second abutment surface; and

limiting the travel of the piston about the extendable portion by contact with the second abutment surface.

23. A method of providing a fluidic connection between a fluid supply and a downhole tubular using a hydraulic connector, the method comprising:

providing the hydraulic connector with a body, a valve assembly, a seal assembly; and an engagement assembly, the engagement assembly comprising an extendable portion with the seal assembly disposed upon a distal end of the extendable portion;

providing the engagement assembly with a piston disposed about the extendable portion and configured to divide a cylinder defined by the body portion into a first chamber and a second chamber;

sealing the first chamber such that it defines a substantially closed system;

providing the first chamber with pressurised fluid to resist extension of the extendable portion;

increasing a pressure of fluids in the fluid supply;

extending the extendable portion;

resisting movement of the piston tending to reduce the volume of the first chamber;

engaging the seal assembly within a proximal end of the downhole tubular;

opening the valve assembly;

hydraulically communicating fluids between the fluid supply and the downhole tubular; and

retracting the seal assembly within the distal end of the body.

24. The method of claim 23 , further comprising:

extending the extendable portion until a first abutment surface disposed on the extendable portion abuts a corresponding abutment surface of the body.