Injection drill bit

1. A device for drilling a hole in a well tubular and for subsequent injection of a fluid or fluid mixture into an annular space or formation surrounding said well tubular comprising:

(a) a housing;

(b) a drill bit assembly arranged inside said housing, said drill bit assembly comprising:

a drill bit having one or more cutting edges and grooves, said one or more cutting edges and said grooves extending along the outside surface of said drill bit;

(c) rotation means connected to said drill bit assembly, said rotation means being capable of rotating said drill bit assembly;

(d) a fluid supply for supplying a fluid or fluid mixture to said grooves of said rotating drill bit;

(e) a drill seal surrounding said drill bit, for forming a seal against said well tubular;

(f) drive means for advancing said drill bit assembly together with said drill seal from said housing towards said well tubular in order to press the drill seal against the well tubular.

2. The device according to claim 1 , wherein said grooves extending along the outside surface of said drill bit are helical grooves.

3. The device according to claim 1 , wherein said fluid supply for supplying a fluid or fluid mixture to said grooves is fluidly connected to at least one container inside said housing, said container being suitable for containing a fluid or fluid mixture.

4. The device according to claim 1 , wherein said fluid supply for supplying a fluid or fluid mixture to said grooves is connected to the end of said drill bit opposite said cutting edge, such that fluid can be transported from the device and into an annular space via said grooves, when said drill bit extends through the well tubular and the drill seal is pressed against the well tubular.

5. The device according to claim 1 , wherein said drive means is configured to retract said drill bit assembly.

6. The device according claim 1 , wherein the pressure of the injected fluid will amplify the sealing effect of said drill seal on injection of said fluid or fluid mixture.

7. The device according to claim 6 , wherein a portion of said drill seal remains within said housing when said drill bit and said drill seal are advanced.

8. The device according to claim 1 , wherein said drill seal has converging inner faces.

9. The device according to claim 1 , comprising a sensor for determining the position of the drill bit in a radial direction.

10. The device according to claim 9 , wherein said sensor is a magnetic sensor that detects the position of a magnet rigidly mounted to a drill sleeve.

11. The device according to claim 1 , wherein said drill bit assembly comprises a rotatable drill sleeve connected to said drill bit and to said drive means.

12. The device according to claim 11 , wherein said drill sleeve is connected to said rotation means.

13. The device according to claim 12 , wherein said drill seal is mounted on said drill sleeve.

14. The device according to claim 1 , comprising means for pressing said device against the inner surface of said well tubular.

15. A method for performing an operation in a well tubular comprising:

lowering a device according to claim 1 into the well tubular;

drilling a hole in the well tubular using the device; and

injecting a fluid into an annular space or formation surrounding the well tubular.

16. A method for performing an operation in a well tubular comprising:

lowering a device according to claim 14 into the well tubular;

drilling a hole in the well tubular using the device; and

injecting a fluid or fluid mixture through the drilled hole in the well tubular.

17. A method of injecting a fluid into a formation, using the device according to claim 1 , wherein a hole is drilled in a well tubular using said drill bit and wherein said fluid is injected while said drill bit extends through said well tubular and the drill seal is pressed against the well tubular.

18. A device for drilling a hole in a well tubular and for subsequent injection of a fluid or fluid mixture into an annular space or formation surrounding said well tubular comprising:

(a) a housing;

(b) a drill bit assembly arranged inside said housing, said drill bit assembly comprising:

a drill bit having one or more cutting edges and grooves, said one or more cutting edges and said grooves extending along the outside surface of said drill bit;

(c) rotation means connected to said drill bit assembly, said rotation means being capable of rotating said drill bit assembly;

(d) a fluid supply for supplying a fluid or fluid mixture to said grooves of said rotating drill bit;

(e) a drill seal surrounding said drill bit, for sealing said device against said well tubular;

(f) drive means for advancing said drill bit assembly together with said drill seal towards said well tubular in order to press the drill seal against the well tubular, wherein the pressure of the injected fluid will amplify the sealing effect of said drill seal on injection of said fluid or fluid mixture.

19. A device for drilling a hole in a well tubular and for subsequent injection of a fluid or fluid mixture into an annular space or formation surrounding said well tubular, comprising:

(a) a housing;

(b) a drill bit assembly arranged inside said housing, said drill bit assembly comprising:

a drill bit having one or more cutting edges and grooves, said one or more cutting edges and said grooves extending along the outside surface of said drill bit;

(c) rotation means connected to said drill bit assembly, said rotation means being capable of rotating said drill bit assembly;

(d) a fluid supply for supplying a fluid or fluid mixture to said grooves of said rotating drill bit;

(e) a drill seal surrounding said drill bit, for sealing said device against said well tubular;

(f) drive means for advancing said drill bit assembly together with said drill seal towards said well tubular in order to press the drill seal against the well tubular, wherein said drill bit assembly comprises a rotatable drill sleeve connected to said drill bit and to said drive means.