Rotary jet bit for jet drilling and cleaning

Abstract

A jet bit ensures precise drilling of holes through the earth's surface, such as drainholes around a well. The jet bit has front rotating orifices and jets to drill a hole in a medium larger than the diameter of the bit. The orifices directed to the rear provide thrust to propel the bit forward by enlarging the drainhole. A stationary shroud extends beyond the front orifices to maintain the front jets rotation. The jet bit may include turbine to control rotation rate and torque on front jets containing rotating shafts. A jet bit can be small enough to turn in a radius of four (4) inches from a vertical wellbore to create a horizontal drainhole. Various mechanical cutters can be mounted on the front of the jet bit to enable cutting with both jets and mechanical cutters.

Description

This application claims priority of provisional application No. 61/743,025 filed on Aug. 24, 2012.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention describes a jet bit for drilling drainholes in the earth and can be used for cleaning tubulars and other materials. One version contains a turbine for controlling rate of rotation of front jets and torque to rotate the shaft connected to the front orifices. One version can be turned in a short radius of four inches from vertical to horizontal for drilling drainholes in oil/gas reservoirs.

2. Description of Related Art

Jet bits (Jet bits) and background for drilling drainholes are described in U.S. Pat. No. 4,790,394 (Dickinson et. al.); U.S. Pat. No. 5,853,056 (Landers); U.S. Pat. No. 6,206,112(Dickinson); U.S. Pat. No. 6,263,984 (Buckman); and U.S. Pat. No. 6,668,948 (Buckman).

Currently no other jet bits exist that have rotating front jet bits that when connected to high pressure hose will turn in a radius of four inches or less from vertical to horizontal to drill horizontal drainholes. It is obvious that the Badger is too large and without a shield to keep the spinning jet bit away for the formation, the friction between the front of the jet bit and formation will cause the front to cease to rotate.

What is needed is a jet bit that can be turned in a radius of less than four inches when connected to a high pressure hose. It needs to have a standoff to enable it to drill a hole through an oil/gas formation without the front of the jet bit ceasing to turn because of friction between it and the formation. It needs to drill drainholes through the earth having diameters large enough for the jet bit to pass through and large enough to allow the cuttings to pass outside the jet bit and the tubular to which the jet bit is attached. It needs to cut hard and soft reservoirs more efficiently and economically than current jet bits in use. The bit should also have thrust force so that it has its own motive force from rear thrusters.

BRIEF SUMMARY OF THE INVENTION

A rotary jet bit is provided that contains a turbine that controls the toque and rate of rotation of front jets and can be turned in a radius of less than four inches from vertical to horizontal to drill drainholes in oil/gas reservoirs. It is designed such that the rotating front jets have a standoff so that the front of the rotating bit will continue to turn and will not come into contact with the formation so that the front jets will continue to turn to continue jet drilling to produce drainholes in the formation and/or removing solid material solid materials from tubulars and other enclosures. The rotary jet bit comprises a non-rotating outer body consisting of inlet housing and a bearing housing connected to a high pressure fluid source; a rotating inner shaft in the outer body that is connected to and rotates a drill head that has orifices. It has a turbine consisting of an inlet of one or more stationary stator blades connected to the outer body and one or more rotating rotor blades attached to the rotating shaft that rotates the shaft connected to a high pressure drill head; a dynamic seal between the outer housing and the rotating shaft to prevent leakage of high pressure fluid past the rotating shaft to the exterior of the jet bit; and a bearing assembly in the bearing housing to transfer hydraulic and mechanical axial loads on the rotating shaft to the non-rotating stationary outer body; thus providing rotating straight jets on front of the drill head to provide more capable and efficient jet drilling than jet bits currently in use that use stationary straight jets or swirling full cone fluid jets.

DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings in which the reference numbers indicate like features and wherein:

FIG. 1a illustrates a complete rotary jet turbine powered jet bit.

FIG. 1b Drawing of a rotary jet turbine powered jet bit with rear orifices.

FIG. 2 A rotating shaft and drill head with front orifices.

FIG. 3 Illustrates fluid flow through stationary turbine vanes thrusting onto rotating turbine vanes to produce torque to rotate shaft.

FIG. 4 Illustrates fluid seal and fluid flow from high pressure to outside.

FIG. 5a Jet bit containing bearings, high pressure fluid passage, and torque created by jets from angled front orifices to turn drill head.

FIG. 5b Jet bit with angled jets on front to produce torque to turn cutter head and containing rear jets for propulsion.

FIG. 6 Dissolvable cap to keep debris from entering nozzle and to enable jet bit to go by sharp transitions.

FIG. 7 Jet bit containing mechanical cutters on the front.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1a contains the elements of a rotary jet bit whereas a rotating shaft 12 turns inside an outer housing 10 with rotating shaft attached to cutting head with orifices 24 to enable the rotating front orifices to effectively drill and clean solid material. The jet bit has an inlet high pressure fluid connection 8 with an inlet housing 10 a bearing housing 14 containing bearings 20 to enable the rotating shaft 12 to turn relative to bearing housing 14. At the front of inlet housing 10 is a turbine 30 with stationary angled vanes to conduct the high pressure fluid into vanes into the rotating turbine to produce rotation of the rotating shaft 12. This high pressure fluid passes through the turbine and through the hollow part of the cutting head and through cutting head orifices 24 that are rotating with the cutter head. The seal 22 serves to reduce the leakage of fluid from the rotating shaft 12 to the outside through bearing exhaust 26; bearing exhaust 26 also reduces pressure on the bearings. Seal 22 can be a labyrinth seal, O-rings, metal seal (example; beryllium copper) and other configurations to contain the high pressure in the conducting channels from the inlet 8, through the turbine vanes and to the orifices 24. This rotary jet bit can be made of very small dimensions with total diameter of less than ½ inch and a length of less than one inch and sizes up to three inches in diameter with lengths greater than eight inches. FIG. 1b has added to the elements of FIG. 1a the rear orifices 28 that create high pressure jets to propel the jet bit forward and also cuts the material the jet bit is drilling to produce larger effective bores and to also improve the removal of cuttings from the drainholes. FIG. 2 illustrates the geometrical relation of the rotating shall 12 to the Cutting Head 18 and illustrates that they are integrally connected and turn at the same rate.

FIG. 3 illustrates that fluid flowing through the stationary inlet vanes of the turbine 30 impinges onto the rotating vanes 32 to produce a rotation of the rotating shaft 18. By sizing these vanes and changing their angles and using different flow rates the rate of rotation of the rotating shaft 12 can be varied from very slow rotation, less than 10 revolutions per minute, to more than 10,000 revolutions per minute. The turbine vanes enable significant torque to power the jet bit turn even with significant frictional forces in the jet bit and/or debris in front of the jet bit. Seal 22 is a labyrinth rotating seal as illustrated in FIG. 4 that seals the high pressure fluid inside the jet bit from the low pressure fluid in the outside of the jet bit. This pressure differential is equal to the pressure drop across the orifices. The pressure drop across the labyrinth seal is created as a small amount of fluid leaks through a series of restrictions in the seal in turbulent flow. This fluid leakage flow passes through bearings 20 and cools and lubricates them. The bearing assembly 20 in the bearing housing 14 transfers the hydraulic and mechanical axial loads on the rotating shaft 12 to the non-rotating stationary outer body. A cylindrical shroud 16 attached to the bearing housing typically extends beyond the front of the cutting head 18 such that the material being cut does not negatively influence the rotation of the cutting head 18. Advantages of the turbine powered jet bit are that the turbine is highly reliable, it can provide considerable torque and power to the rotating shaft and cutter head, and the rotary speed and torque of the turbine can be varied by the design of the turbine vanes, and by varying the flow rate and the pressure differential across the turbine.

FIG. 4 illustrates the flow of liquid through the seals with a small amount flowing on the outside to of the bearings.

FIG. 5a consists of an embodiment that has the same elements as the jet rotary turbine powered jet bits in FIG. 1b with the turbine vanes removed. In this rotary jet bit the torque produced on the cutting head 18 and the rotating shaft 12 is by the reaction of the torque generated by the fluid through the orifices located on the cutter head 18. The rear jets due to orifices 28 will provide thrust to propel the jet bit forward and the high pressure jets will also cut the material to make a larger equivalent drainhole. FIG. 5a has the same elements as FIG. 5b without the rear orifices 26. In this case the jet bit is attached to a tubular and pushed forward by the tubular force at connection inlet 8.

FIG. 6 consist of a protector cap 34 that is placed on the jet bit to protect the head from debris and allow clearance through sharp transitions. The protector cap 34 is a water soluble material that dissolves away and does not to disrupt cutting operations.

FIG. 7 is similar to FIG. 5b with the addition of mechanical cutters 40 also on front of the jet bit to enable the bit to cut both with high pressure jets and also mechanical cutters such as polycrystalline diamond (PDC), tungsten carbide, silicon carbide, or silicon nitride.

DESCRIPTION OF PREFERRED EMBODIMENT

Let us now consider one preferred embodiment of the turbo jet drill used to jet drill drainholes in wells in the earth. The Parts 10, 12, 14, 16, 18, 30 and 32 are constructed using stainless steel. The total diameter of the jet bit is nominally ½ inch and the length is about 1.2 inches. The jet bit is designed to withstand pressures of 15,000 psi or more and the front bit and turbine are designed to turn at a rate of 200 rpm or greater with a thrust force from the rear jets of 10 lbs. to more than 50 pounds.

Claims

1. A jet bit for jet drilling, comprising:

a non-rotating outer body consisting of inlet housing and a bearing housing connected to a high pressure fluid source;

a rotating inner shaft in the outer body that is connected to and rotates a drill head;

a drill head has orifices that under high pressure fluid are angled to produce torque to turn the drill head and to produce high pressure fluid jets to drill solid materials;

a turbine consisting of one or more stationary stator blades attached to the outer body and one or more rotating rotor blades attached to the rotating shaft to rotate the shaft and the high pressure drill head;

a dynamic seal on the rotating shaft to prevent leakage of high pressure fluid past the rotating shaft to the exterior of the jet bit and reducing flow through the drill head;

a bearing assembly in the bearing housing to transfer hydraulic and mechanical axial loads on the rotating shaft to the non-rotating stationary outer body. The jet bit of claim 1 where the fluid pressure drop across the orifices is between 500 and 40,000 pounds per square inch.

1. The jet bit of claim 1 including a turbine consisting of one or more stationary stator blades attached to the outer body and one or more rotating rotor blades attached to the rotating shaft to rotate the shaft and the high pressure drill head.

2. The jet bit of claim 1 where the inlet housing and bearing housing are combined into one housing.

3. The jet bit of claim 1 where rear directed orifices in the non-rotating outer body produce jets that produce a forward force on the drill head as it drills.

4. The jet bit of claim 4 where rear directed jets cut slots in the in the rock surrounding the jet drilled holes to increase flow of oil and gas from oil and gas bearing formations.

5. The jet bit of claim 1 where one or more side directed jets in the drill head are used to increase the diameter of the jet drilled hole.

6. The jet bit of claim 1 where angled jet bits are used in the drill head to provide torque to rotate the shaft and drill head instead of turbine blades.

7. The jet bit of claim 1 where a Moineau motor is used to rotate the shaft and high pressure drill head.

8. The jet bit of claim 1 where the bearing assembly is a ball or roller bearing.

9. The jet bit of claim 1 where the bearing assembly is a hard-metal sliding bearing that utilizes polycrystalline diamond, ceramic or other hard-metal sliding surfaces.

10. The jet bit of claim 1 where the bearing assembly is a journal bearing.

11. The jet bit of claim 1 where the dynamic seal is a labyrinth seal.

12. The jet bit of claim 1 where the dynamic seal is an o-ring seal.

13. The jet bit of claim 1 where the dynamic seal is a metal to metal seal.

14. The jet bit of claim 1 where the dynamic seal is a deformable material seal.

15. The jet bit of claim 1 where the dynamic seal is a face seal.

16. The jet bit of claim 1 where the dynamic seal is a lip seal.

17. The jet bit of claim 1 where the dynamic seal is a packing seal.

18. The jet bit of claim 1 where the dynamic seal is a nested V or a nested conical seal.

19. The jet bit of claim 1 where the dynamic seal is a mechanical seal.

20. The jet bit of claim 1 where the dynamic seal is a balanced or unbalanced seals.

21. The jet bit of claim 1 where a screen is placed in the jet bit to prevent small particles from plugging the high pressure orifices.

22. The jet bit of claim 1 where hard-metal mechanical cutters such a polycrystalline diamond (PDC), tungsten carbide, silicon carbide and silicon nitride cutters are applied to the drill head to assist the high pressure jets in drilling hard materials.

23. The jet bit of claim 1 where the drill head is contained in a shroud to protect it from mechanical damage or plugging by debris from the material being drilled.

24. The jet bit of claim 1 where the assembly is pushed forward mechanically by a tube or other means instead of by rear jets.

25. The jet bit of claim 1 where a diverter is used in an existing well to turn the jet rotating head so that it will drill inclined or horizontal lateral wells from existing wellbores.

26. The jet bit of claim 1 where a flexible tube or hose is used behind the rotating drill head to allow passage through the curved passageway in the diverter.

27. The jet bit of claim 1 where the outer body of the jet drilling assembly is flexible so that that the assembly can pass around shorter radii turns in diverters.

28. The jet bit of claim 1 where a hydraulic or electric motor is used in an existing well to rotate a flexible shaft that passes through a diverter and rotate the jet drilling assembly to drill inclined or horizontal lateral wells from existing wellbores.

29. The jet bit of claim 1 where the jet bit is used to remove cement, scale, paraffin and other materials from inside oilfield drillpipe, oil and gas production tubing, oilfield casing and from tubulars in geothermal, water, and disposal wells.

30. The jet bit of claim 1 where the jet bit is used clean the inside of industrial tubing such as heat exchanger tubes.

31. The jet bit of claim 1 where the jet bit is used to clean products in non-drilling applications.

32. The jet bit of claim 4 where the jet bit rear jets and front jets are both used for cleaning.

33. The jet bit of 1 where it uses a water soluble protector cap to allow clearance through sharp transitions and protects from debris.