DOWNHOLE CUTTING TOOL
An apparatus and method of cutting an object in a wellbore including a downhole cutting tool having a source of abrasive material; a source of high pressure fluid mixable with the abrasive material; a rotatable nozzle section, the nozzle section rotatable due to a source of low pressure fluid acting on a piston surface formed on a sleeve, the sleeve rotationally and axially movable in a body of the tool; whereby the sources of high and low pressure fluid and the abrasive material are housed in the tool.
1. Field of the Invention
Embodiments of the present invention generally relate to a downhole cutting tool. More particularly, the embodiments relate to a downhole water/abrasive cutter for use with a safety valve.
2. Description of the Related Art
A downhole safety valve refers to a component in an oil and gas well which acts as a failsafe to prevent the uncontrolled release of reservoir fluids in the event of a worst case scenario surface event. It is almost always installed as a vital component on the production tubing string. The valves typically have a “flapper” that closes against upward pressure in the event of an emergency. In normal use, the flapper is retained in an open position due to a sleeve that extends through the bore of the valve and prevents the flapper from closing. The sleeve is held in place with positive hydraulic control pressure from a control line. In the event of a loss in control pressure, the tube retracts and the flapper closes against a seat.
In the event of a malfunction of a tubing mounted safety valve, replacement would typically mean pulling the production string. Rather than suffer this type loss in time and revenue, the tubing valve is permanently locked in the open position and a replacement valve is run into the well, typically on wireline. The new valve has a smaller diameter than the first one but requires the same source of pressurized fluid to keep it open in normal operations. This means accessing the control line pressure from the existing valve body, typically by penetrating a metallic wall of the body. Current solutions include downhole cutters utilizing batteries and printed circuit boards to power a rotating cutting head and a downhole machining operation run on wireline. Batteries and circuit boards are delicate, and downhole machining requires high and surging torque that can be problematic. Other solutions permit an aperture to be formed through the wall of the valve body with a punching operation but also require that the punching device be rotationally positioned to form the aperture at the right location. There is a need therefore for a better way to cut material downhole. There is a more particular need for an apparatus and method to access a source of control fluid to be utilized by a replacement downhole safety valve.
SUMMARY OF THE INVENTIONIn one aspect, the invention includes a downhole cutting tool having a source of abrasive material; a source of high pressure fluid mixable with the abrasive material; a rotatable nozzle section, the nozzle section rotatable due to a source of low pressure fluid acting on a piston surface formed on a sleeve, the sleeve rotationally and axially movable in a body of the tool; whereby the sources of high and low pressure fluid and the abrasive material are housed in the tool. In another aspect the invention includes a method of operating a tool having the forgoing characteristics.
So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
In one embodiment, a downhole tool is run into a wellbore on wireline in order to access a source of hydraulic control fluid to be utilized by a wireline safety valve that will be installed later. The tool cuts through a “web” of metal that separates the source of fluid from an interior of the body of a tubing-run safety valve that has been permanently locked out due to a malfunction. Wireline deployed safety valves and well know in the art and described in one instance in a catalogue viewable on the web site of Weatherford International at [http://www.weatherford.com/ECMWEBgroups/web/documents/weatherfordcorp/WFT003619.pdf] and that publication is incorporated by reference herein.
The tool of the present invention includes a rotating nozzle section along with a source of high pressure and low pressure fluid, like water and a source of abrasive material, like Garnett abrasive. In this disclosure, high and low fluids mean that the high pressure fluid is of a higher pressure than the low pressure fluid. The tool is designed to be run into the well and then, at a predetermined time and location, actuated wherein the cutter nozzle rotates as a high pressure stream of water and abrasive is applied to an internal surface of the safety valve body. High pressure water cutters using abrasive material are well known in the art. In this disclosure, the term “cutting” refers to any removal of material made by the tool, including but not limited to apertures, cuts, slots, and grooves.
The abrasive section 23 is also shown in the Figure and includes a source of abrasive material in a chamber 24 and a line 25 that extends to the nozzle where it is mixed with the high pressure water during cutting. As stated herein, the abrasive material, typically Garnett is not pressurized but enters the stream of water due to suction-like property created in an expanded area of the nozzle section 12. In one embodiment, a pocket of air is provided behind the abrasive material in the chamber to prevent a vacuum being formed.
The tool 10 is typically loaded with water and nitrogen at the surface of the well. In one example, 500 psi nitrogen is loaded into the high pressure section 21 at a surface temperature of 100 degrees Fahrenheit. The lower pressure water section 22 is loaded to a pressure of 100 psi at the same temperature. After run-in to a depth where it will be operated, the downhole temperature might be 300 degrees Fahrenheit, resulting in an effective pressure of 1,500 psi and 300 psi respectively. Furthermore, due to the multiplying effect of the pistons areas 51, 52 in the high pressure section 21, the actual pressure of the cutting fluid will be about 30,000 psi. In a typical application, the distance between the end of the nozzle 14 and the web portion 115 to be penetrated is about 0.200″ and the web portion itself is about 0.106″. Also, a typical tubing run valve body has an eccentric bore in the area of the web that causes the nozzle 14 to be slightly closer to the wall of the body in the area of the web.
In practice, the tool 10 is run into the wellbore on wire line and seated against the no-go area 110 formed on an interior of the existing valve body 120. Initially, an interior portion of the tool and an exterior portion are separated and retained in that separated position by shear pins 135. In the initial condition shown in
Various features of the tool 10 facilitate its downhole use. For example, the lines carrying water and abrasive are provided with additional coils of length to permit assembly and rotation of the nozzle section 12. Additionally, a spring loaded button member 125 serves to retain the rotating sleeve 65 in its initial position prior to being urged downwards by the low pressure water. An indicator 95 is useful to ensure the tool is seated in the valve body 120 rather than being inadvertently seated at some location thereabove. In the initial pinned position, the indicator 120 extends partially into a recess 97 formed in the valve body 120. As the pins 135 are sheared and the inner portion moves down, a sloped shoulder 96 moves the indicator out and into the recess 97.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
Claims
1. A method of cutting an object in a wellbore, comprising:
- providing a tool including a rotatable nozzle section and nozzle, a source of high pressure fluid, a source of low pressure fluid, and a source of abrasive material;
- running the tool into the wellbore to a predetermined location where the nozzle is adjacent the object;
- actuating the tool whereby the nozzle section rotates between 180 and 360 degrees while the high pressure fluid and abrasive are released from the nozzle.
2. The method of claim 1, wherein actuation takes place when an inner portion of the tool is moved relative to an outer portion thereof.
3. The method of claim 2, wherein rotation of the nozzle section takes place as a result of the low pressure fluid acting on a piston surface formed on a rotatable and axially movable sleeve, the sleeve housed in a body of the tool.
4. The method of claim 3, wherein actuation results in an aperture formed in a wall of material adjacent the nozzle.
5. The method of claim 4, wherein the wall of material separates the nozzle from a source of hydraulic control fluid.
6. A downhole cutting tool, comprising:
- a source of abrasive material;
- a source of higher pressure fluid mixable with the abrasive material;
- a rotatable nozzle section, the nozzle section rotatable due to a source of lower pressure fluid acting on a piston surface formed on a sleeve, the sleeve rotationally and axially movable in a body of the tool; whereby
- the sources of higher and lower pressure fluid and the abrasive material are housed in the tool.
7. The tool of claim 6, wherein the higher pressure fluid is selectively exposed to the nozzle section and the lower pressure fluid is selectively exposed to the piston surface of the sleeve by remotely opening valves in the body of the tool.
8. The tool of claim 7, wherein the valves are opened due to movement of the valves in relation to a housing around each valve.
9. The tool of claim 8, wherein the movement is initially prevented with at least one shear pin.
10. The tool of claim 9, wherein the higher pressure fluid is provided in a high pressure section that includes a higher pressure fluid chamber and a source of pressurized gas, the fluid and gas separated by a piston, the piston having a relatively large piston area adjacent the gas and a relatively small piston area adjacent the fluid.
11. The tool of claim 10, wherein the lower pressure fluid is provided in a low pressure section that includes a lower pressure fluid chamber and a source of pressurized gas separated by a piston.
12. The tool of claim 11, wherein the sleeve includes an upper spiral-shaped groove formed in its outer surface, the groove constructed and arranged to cause the sleeve to rotate as it moves downwards in the tool body, rotation caused by an inwardly facing pin extending into the groove from an inner surface of the body.
13. The tool of claim 12, wherein the sleeve further includes a lower spiral-shaped groove formed in its outer surface, the groove constructed and arranged to cause the nozzle section to rotate as the sleeve moves downwards in the nozzle section, rotation of the nozzle section caused by a lower inwardly facing pin extending into the groove from an inner surface of the nozzle section.
14. The tool of claim 13, wherein the higher pressure fluid, at the time of a cutting operation is at a pressure of about 30,000 psi and the lower pressure fluid is at a pressure of about 300 psi.
15. The tool of claim 14, wherein the tool is constructed and arranged to seat itself in a body of a downhole valve.
16. The tool of claim 15, further including an indicator, the indicator mounted on the tool an constructed and arranged to extend into a recess formed on an inside surface of the body of the downhole valve when the valves of the tool are opened.
17. The tool of claim 16, wherein the object is a wall of material separating the tool from a source of control fluid to operate a replacement safety valve.
18. The tool of claim 17, wherein the cutting operation takes place in an interior of a valve housing, the interior having an eccentric shape whereby the cutting operation results in a cut that does not extend completely around an interior of the valve housing.
19. An apparatus for rotating a nozzle of a downhole cutter, comprising:
- a body having a rotatable nozzle section at a lower end thereof;
- a sleeve housed in the body, the sleeve rotatable and axially movable within the body and including a piston surface formed on an outer surface thereof, the outer diameter of the sleeve enlarged in the area of the piston surface;
- a source of pressurized fluid, the fluid selectively usable to act upon the piston surface;
- a first spiraling groove formed in an outer surface of the sleeve, the groove housing a first pin, the pin formed on an inner surface of the body;
- a second spiraling groove in the outer surface of the sleeve, the second spiraling groove housing a second pin, the pin formed on an inner surface of the rotatable nozzle section; whereby
- when the fluid acts on the piston surface, rotational and axial movement of the sleeve within the body and rotation of the nozzle section is determined by the pins and grooves.
Type: Application
Filed: Apr 3, 2015
Publication Date: Oct 8, 2015
Inventors: Winfield M. SIDES, III (Bellaire, TX), Luis BARRIENTOS (Katy, TX)
Application Number: 14/678,116