GB2481848A

GB2481848A - Self sealing drill rods

Info

Publication number: GB2481848A
Application number: GB1011562.4A
Authority: GB
Inventors: Michael Roger Nunn
Original assignee: MINE INNOVATION Ltd
Current assignee: MINE INNOVATION Ltd
Priority date: 2010-07-09
Filing date: 2010-07-09
Publication date: 2012-01-11
Also published as: GB201011562D0

Abstract

Valve assembly 30 for a drill rod 16 having a through passage 35. The valve 30 is moved from a closed to an open condition when drill rods are connected to one another. A mechanical connection between adjacent drill pipes 16 causes the operation of the seal assembly 30. There may be connection assemblies 20/22 at either end of the drilling pipe 16 which include a valve assembly. The valve assembly 30 can have first and second valve portions 31a/31b. There may be a closure member (38, fig 3) which engages a sealing surface (50, fig 3). There can be a biasing means 56 for the closure member. There may be an actuator member 41 which can move the closure member when engaging the actuator of an adjacent drill rod.

Description

Drilling Equipment The present invention relates to drilling equipment, and particularly, but not exclusively, to apparatus and methods for connecting drill rods (also known as drill pipes or steels).

Drill rods are generally used in a drilling machine, which comprises a drill bit mounted on a drill rod. The drill rod is caused to rotate by a drive arrangement, so as to drill into a material adjacent the drilling machine.

It is often possible to connect multiple drill rods together to form a drill string comprising a plurality of drill rods. Thus it is possible to drill holes which are longer than the length of a single drill rod. Conventionally two adjacent drill rods are manually connected together, by screwing or otherwise connecting one rod directly to another, or both rods to a joint or sleeve. When a portion of the hole has been drilled, the drill string is disconnected from the drive arrangement to allow a further drill rod to be connected to lengthen the drill string.

Drill rods may include an open ended internal passage to convey a medium, for example a fluid such as a drill mud down through the drill string toward the drill bit. Such fluid may leak through the open ends when the drill rods are disconnected, resulting in loss of the fluid.

One example of a drilling machine is a drilling rig. Conventionally drilling rigs are used to drill into a material such as rock or earth adjacent, and generally below, the drilling rig. In general, drilling rigs are used to bore holes or shafts into the ground, often for the purpose of locating or extracting a substance, such as rock, oil, minerals or water, for installing a construction, such as foundations or a well, or in blasting operations, such as driving a tunnel.

Multiple types of drill rods are available, and which drill rod is used depends at least in part on the material to be drilled. Drill rods are generally substantially cylindrical, and may comprise auger flights which assist in removing drilled material from the hole.

According to a first aspect of the present invention there is provided a drill rod comprising a longitudinal through passage, and a valve assembly having a first condition in which the valve assembly is closed so as to seal the through passage and a second condition in which the valve assembly is open so as to open the through passage, the valve assembly being movable from the first condition to the second condition by connection of the drill rod to an adjacent drill rod.

The valve assembly may thus be operable to open due to a mechanical connection being made between two drill rods.

The drill rod may be for use in a drilling rig.

The valve assembly may be movable from the second condition to the first condition by disconnection of the drill rod from an adjacent drill rod. Thus the valve may be arranged to automatically close when two connected drill rods are disconnected.

The valve assembly may be located anywhere along the length of the drill rod, for example substantially at all adjacent an end of the drill rod.

The valve assembly may comprise first and second valve portions.

The first valve portion may be located at a first end of the drill rod, and a second, complementary valve portion may be located at a second end of the drill rod. Thus, where a plurality of similar or substantially identical drill rods are provided, the first and second valve portions of adjacent drill rods may be connected together, so as to form a drill string.

The drill rod may include a connection assembly including a first connection member and a second connection member. The first connection member may be located at a first end of a drill rod, and the second connection member may be located at a second end of the drill rod. The first and second connection members may be adapted to engage with respective second and first connection members located on adjacent drill rods and may be adapted to provide a substantially fluid tight connection between the adjacent drill rods when connected. The connection assembly may include a valve assembly.

The valve assembly may include a closure member which is operable to move between a closed position when the valve assembly is in the first condition and an open position when the valve assembly is in the second condition. The closure member may be movable, e.g. slidable, such that, in the closed condition, the closure member engages against a sealing surface of the valve assembly to substantially close the through passage of the drill rod, while in the open condition the closure member may be spaced from the sealing surface to allow a medium, in particular a fluidised medium such as a fluid (which may be liquid or gas, for example drilling mud, or air) or suspension, to flow through the through passage. The valve assembly may comprise a guide for guiding the movement of the closure member.

The valve assembly may include biasing means such as a spring for biasing the closure member toward the closed condition.

The valve assembly may include an actuator which may move the closure member from the open condition to the closed condition, and/or between the open and closed conditions. The actuator may be mechanical, i.e. operable to move under the influence of a mechanical force.

The actuator may comprise a rod member which may extend from the closure member. The rod member may extend along a longitudinal axis of the drill rod, away from the closure member and towards an end of the drill rod.

Where the valve assembly comprises first and second valve portions, each of the first and second valve portions may comprise a respective closure member and actuator. The valve portions may be arranged so that, in use, when the ends of adjacent drill rods are connected, a surface of the actuator (e.g. a rod member) of the first valve portion of one drill rod may engage against a surface of the actuator (e.g. rod member) of the second valve portion of another drill rod. In this way, connecting two adjacent drill rods may actuate the closure members of each drill rod so as to open each valve portion, and connect the through passages of the drill rods.

According to a second aspect of the present invention there is provided a valve assembly for connecting adjacent drill rods, the valve assembly having a first condition in which the valve assembly is closed and a second condition in which the valve assembly is open, the valve assembly being moveable from the first condition to the second condition by connection of the adjacent drill rods.

It will be appreciated that the valve assembly might comprise any of the features discussed above with respect to a valve assembly of a drill rod of the first aspect of the invention.

According to a third aspect of the present invention there is provided a drilling machine comprising a drill rod in accordance with the first aspect of the invention. The drilling machine may be a drilling rig.

The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 115 a diagrammatic side view of a drilling rig; Figure 2 is a cross sectional side view of a drill rod; Figure 3 is a cross sectional view a first valve portion in a closed condition; Figure 4 is a cross sectional view of a second valve portion in a closed condition; Figure 5 is a partial cross sectional view showing the valve portions of Figures 3 and 4 connected in an open condition; and Figures 6A, B and C show various examples of guides for use a valve.

Figure 1 shows a diagrammatic side view of a drilling rig 10. The drilling rig 10 includes a drill head 110 including a drive arrangement 112 for driving a drill string 114 comprising a plurality of interconnected elongate drill rods 16. In this example, two drill rods 16 are provided, although it will be appreciated that in many instances a larger number of drill rods might comprise the drill string 114. Each drill rod 16 shown includes a plurality of augers 116 for drilling into the ground 118, although it will be appreciated that these are optional, and drill rods without augers might be used. The drill string terminates in a drill bit 120 at a drilling end of the drill string that is remote from the drive means 112.

Referring to Figure 2, each drill rod includes a through passage 34, and may be substantially hollow. The through passage 34 provides a channel which in use permits a medium, and in this case a fluid, to flow from the drill head 110 toward the drill bit 1 20 at the drilling end of the drill string (for example for lubrication of the drill bit, or to damp any sparks that may occur as a result of the drilling).

The drill rod 16 includes a first end 12 and a second end 14. The first and second ends are arranged so that the first end of a first drill rod can be connected to a second end of a second similar or substantially identical drill rod to form the drill string 114. In particular, the drill rod includes a connection arrangement 20, which in use assists in connecting adjacent drill rods 16 to form the drill string. The connection arrangement 20 comprises a first connection member 22 and a second connection member 24 located respectively at the first and second ends 12, 14 of the drill rod 16.

The first connection member 22 includes socket in the form of an open ended recess 26 into which a complementary shaped projection 28 of the second connection member 24 can be located. One or more resiliently deformable sealing members are provided around the projection 28 to ensure a fluid tight seal in use.

Each dri'l rod 16 further includes a valve assembly 30 in communication with the through passage 34 of the drill rod. The valve assembly has a first condition (shown more clearly in Figures 3 and 4) in which the valve assembly is closed so as to seal the through passage, and a second condition (shown in Figure 5) in which the valve assembly is open so as to open the through passage. The valve assembly is movable from the first condition to the second condition by connecting a drill rod to an adjacent drill rod, as will be discussed in more detail below.

The valve assembly 30 includes a substantially hollow interior portion in the form of a chamber 32 which is in fluid communication with the through passage 34 of the drill rod 16. The valve assembly further includes a closure member 38 which is operable to move between a closed position when the valve assembly is in the first condition and an open position when the valve assembly is in the second condition, so as to open the valve and permit fluid flow into the drill rod through passage.

In the example shown in the Figures, the valve assembly comprises first and second valve portions 31a, 31b. The valve portions are arranged (e.g. suitably shaped) so that the first valve portion cooperates with the second valve portion, so that the first valve portion of a first drill rod can be connected with the second valve portion of a second, similar drill rod, to connect the drill rods, and in particular to connect the through passages of the drill rods to form a substantially continuous passage along which in use a fluid can flow. When the drill rods are disconnected the valve portions automatically close, sealing the through passages of the drill rods and preventing fluid from escaping and being lost.

The first and second valve portions 31a and 31b are in this example located in the connection arrangement 20.

Referring now to Figure 3, a first valve portion 31a is shown. The first valve portion 31a includes a closure member in the form of a stopper or plug 38.

The closure member 38 is located within a chamber portion 32 of the valve portion 31 a. A mechanical actuator in the form of a first rod member 41 is operatively connected to the closure member, such that the closure member moves under the influence of the actuator. In this case, the plug is mounted on the rod member 41. The rod member extends longitudinally away from the plug 38 towards the external end of the valve member, and towards the end of the drill rod. In the example shown, the rod member 41 extends substantially axially, in line with a longitudinal axis 60 of the drill rod 16.

Guides 42 are provided in the chamber 32, and the rod member 41 is mounted within the valve portion 31a by those guides 42. In use, the guides allow the rod member 41 to move (e.g. slide) in a lateral direction, indicated in Figure 3 by the arrow X. The guides 42 include flow passages to allow the fluid to pass through the valve when in the open condition, which may comprise a relief, holes or cut-outs to allow the flow of the fluid. The guides 42 are held in place by fasteners, such as stoppers in the form of circlips 44, which act to prevent lateral movement of the guides 42.

Three guides 42, 42a and 42b are shown in Figures 6A, 6B and 6C respectively. Each guide 42 includes a central bore 43 which in use slidably supports a rod member 41. Each guide also includes one or more flow passages 45 through which, in use the fluid or medium may pass.

The number, size and location of the flow passages is dependent to some extent on the flow rate which is desired or expected through the valve.

For instance, Figure 6B shows a guide member 42a having three part-circular flow passages. The guide member 42a is suitable for use with a high flow, because the flow passages permit flow through a substantial part of the cross sectional area of the chamber. Figure 6C shows a guide member 42b having a plurality of small circular passages, which is suitable for use with a lower flow, as a smaller portion of the cross sectional is available for fluid flow.

Figure 6A shows a guide member having four substantially quarter-circular flow passages, which is suitable for an intermediate level of flow. It will be appreciated that other numbers, sizes and locations of flow passages are possible to those depicted in Figures 6A to 6C.

The plug 38 is located within an increased diameter part 47 of the chamber 32. The plug 38 has a smaller diameter than the increased diameter part 47, but a larger diameter than an entry region 35 of the chamber 32. A sealing region 49, having a sealing surface 50, which in this example is sloping, connects the entry region 35 of the chamber 32 to the larger diameter part 47.

The plug 38 comprises an engaging surface 48 which is of a complementary shape to the sealing surface 50. In the example shown the engaging surface of the plug 38 is tapered, or frusto-conical. In the closed condition, as shown in Figure 3, the engaging surface of the plug tightly abuts the sealing surface of the valve portion, substantially preventing fluid from flowing therethrough.

The plug 38 is biased towards the closed condition by biasing means in the form of a resiUent member such as a spring 56, which engages against the guide 42 to push the plug towards the sealing surface. In use, when a sufficient force is applied axially to the rod member 41 the spring 56 is caused to compress. The rod member and closure member then move axially in the direction indicated by arrow Y under the influence of the force towards the open position, thus opening the valve. In the event that the force is discontinued, the spring acts to return the closure member to the closed position.

Referring now to Figure 4, a second valve portion 31 b is shown. It will be seen that the second valve portion 31 b is substantially similar to the first valve portion 31a, and like numerals have been used to designate like parts where appropriate.

In particular, the second valve portion 31b comprises a closure member 38 located within a chamber 32 in the valve portion. The closure member 38 comprises an engaging surface 48 operable to abut a sealing surface 50 provided in a sealing region 49 of the chamber 32 when the closure member is in a closed portion, so as to substantially prevent the flow of fluid through the valve portion.

An actuator in the form of a mechanical actuator, or rod member 41, is operable in use to move the closure member 38 from the closed position to an open position under the influence of a force. A biasing element 56, such as a spring, is operable to return the closure member to the closed position when the force is removed.

In the example shown, it will be seen that the first and second valve portions differ only in the shape of location members 57 which are provided on the valve portions, in order to allow the valve portions to be more easily aligned. In particular, the location member of the first valve member 31a comprises a female fitting, including an open ended recess 58, into which a complementary male fitting, including a projection 59 provided on the second valve member 31 b can be located.

Both the first and second valve portions 31a and 31 b are affixed to the ends 12, 14 of the drill rod 16 by a threaded hexagonal connector 36 (although other fittings could also be used, or the valves might be formed integrally with the connector/drill rod). Where the valve portions are formed separately from, and for example threadedly connected to, the drill rod, if required the valve portions 31a and 31b can be removed from the drill rod 16, for example for replacement, or refitting to another drill rod.

Figure 5 is a partial view showing two drill rods 16 in a connected condition. In use, two drill rods are connected by first aligning the longitudinal axes 60 of the valves (which in this example is substantially the same as aligning the longitudinal axes of the drill rods 16). When the axes 60 are aligned, the drill rods 16 are then pushed towards each other, so that the actuator of the first valve portion (and in particular, a remote end surface 54 of the rod member 41) contacts the actuator of the second valve portion (and in particular, a remote end surface 55 of the rod member 41).

As the adjacent drill rods 16 are pushed together, a force is exerted on the rod members 41 such each rod member 41 causes the respective closure 38 to move generally axially away from the sealing surface 50, thereby compressing the spring 56 and opening each valve portion 31a, 31b of the valve assembly 30 to allow fluid to flow through the valve assembly and between the through passages 34 of the adjacent drill rods 16.

In use the connection arrangement acts as a guide to assist in aligning the first valve portion of a first drill rod with the second valve portion of a second drill rod, to assist in connecting the valve portions (and in particular, aligning the rod members of the valve portions). When aligned, the location member of the second valve portion 31b or a drill rod is located within the location member of the first valve portion 31a of an adjacent drill rod, and the second connection member 24 of the second valve portion 31 b is received within the first connection member 22 of the first valve portion 31a, in order to connect the drill rods. The connection arrangement assists in maintaining the alignment of the drill rods when the drill rods are connected (by substantially resisting angular movement of one drill rod with respect to another drill rod to which it is connected).

Stop members 52A and 52B are provided on the respective first and second connection members. The length of the rod members 41 in relation to the location of the stop members 52 is sufficient that in order for the adjacent drill rods to be fully connected both valve portions 31a, 31b must open to some extent.

The valve assembly includes a seal which in use substantially prevents fluid leaking from the open valve. In this example, the seal is located in the recess 46 provided on the second valve portion.

When the adjacent drill rods 16 are then disconnected, for instance to add a further drill rod 16 to the upper in use end of the drill string, the respective springs 56 will decompress to cause the closure members 38 to slide back toward the sealing surlaces and into the closed condition, as the ends 54, 55 of the rod members 41 disengage from each other.

Various advantages are provided by the described invention. The invention provides a means for automatically connecting the through passages of adjacent drill rods in a drill string without any intervention by a user. The invention further provides a means for automatically sealing the through passage of a drill rod when it is disconnected from a drill string without any intervention by a user. Only a relatively small quantity of fluid may escape from the drill rods when disconnected, which may result in reduced operating costs and pollution caused by drilling.

The apparatus does not depend on fluid pressure to open or close the valve assembly, such that the valve will automatically open when adjacent drill rods are connected, and close when adjacent drill rods are disconnected, even when there is little or no fluid pressure in the drill string.

The apparatus is of relatively robust and simple construction, and can be fitted to existing drill rods (by locating a valve member as discussed above in communication with the through passages of an existing drill rod).

Various modifications may be made without departing from the scope of the invention. For instance, alternative closure members and/or mechanical actuators might be used than those described above, such as spool or sleeve valve arrangments.

It will be appreciated that the invention has been described showing a valve portion on each end of a drill rod. It will be appreciated that this is not necessary, as a single valve assembly might be provided on a single end of a drill rod, (where a suitably shaped actuator is provided on the opposite end of the drill rod). Such an arrangement might be useful, for example, in preventing fluid from escaping from one end of a drill rod under the influence of gravity, where there is little or no risk of fluid escaping from the other end of the drill rod (for example in the case of vertical drilling). However, in such instances back pressure may nevertheless cause fluid to escape from the upper end of a drill rod, and so it is preferred to include valve portions on both ends of a drill rod, so as to seal both ends of the drill rod when it is disconnected from adjacent drill rods.

It will be appreciated that the valve arrangement, and/or one or both of the valve portions, might be provided on a sleeve or joint for connecting two drill rods, rather than on one or both of the drill rods themselves.

The valve arrangement, and/or one or both of the valve portions, might be formed separately from a drill rod, and connected to the drill rod in a suitable way, for example by welding, screwing, or gluing. It is preferred that the valve arrangement is removably connected to a drill rod, for example by screwing, so that it can be replaced if necessary.

It will be appreciated that the connection members and location members discussed above are not required. Whilst they are useful to assist in locating a valve portion of a first drill rod in relation to a valve portion of a second drill rod, other suitable location means (for example in the form of a mechanised assembly apparatus) might be provided, and other suitable connection arrangements might be provided (for example in the form of a sleeve).

Whilst the invention has mainly been described in relation to a drilling rig, it will be appreciated that the invention is also applicable for use in other types of drilling machine, for example a hand-held drill. As discussed above, drill rods come in many forms, and the invention described above can be used with any of those forms, and in particular straight drill rods, auger drill rods and casing rods.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

Claims 1. A drill rod comprising a longitudinal through passage, and a valve assembly having a first condition in which the valve assembly is closed so as to seal the through passage and a second condition in which the valve assembly is open so as to open the through passage, the valve assembly being movable from the first condition to the second condition by connection of the drill rod to an adjacent drill rod.
2. A drill rod according to claim 1 in which the valve assembly is operable to open due to a mechanical connection being made between two drill rods.
3. A drill rod according to claims 1 or 2, in which the drill rod is for use in a drilling rig.

*....
4. A drill rod according to any of the preceding claims, in which the drill rod includes a connection assembly including a first connection member S.. and a second connection member.
5. A drill rod according to claim 4, in which the first connection member is located at a first end of a drill rod, and the second connection member is located at a second end of the drill rod.
6. A drill rod according to claim 5, in which the first and second connection members are adapted to engage with respective second and first connection members located on adjacent drill rods.
7. A drill rod according to claim 6, in which the first and second connection members are adapted to provide a substantially fluid tight connection between the adjacent drill rods when connected.
8. A drill rod according to any of claims 4 to 7, in which the connection assembly includes a valve assembly.
9. A drill rod according to any of the preceding claims, in which the valve assembly is movable from the second condition to the first condition by disconnection of the drill rod from an adjacent drill rod, and thus the valve is arranged to automatically close when two connected drill rods are disconnected.
10. A drill rod according to any of the preceding claims, in which the valve assembly is located at or adjacent an end of the drill rod.
11. A drill rod according to any of the preceding claims, in which the valve assembly comprises first and second valve portions.

* : .
12. A drill rod according to claim 11, in which the first valve portion is located at a first end of the drill rod, and a second complementary valve portion is located atasecond end of the drill rod.
13. A drill rod according to claim 12, in which where a plurality of similar or substantially identical drill rods are provided, the first and second valve portions of adjacent drill rods may be connected together, so as to form a drill string.
14. A drill rod according to any of the preceding claims, in which the valve assembly includes a closure member which is operable to move between a closed position when the valve assembly is in the first condition and an open position when the valve assembly is in the second condition.
15. A drill rod according to claim 14, in which the closure member is moveable such that in the closed condition, the closure member engages against a sealing surface of the valve assembly to substantially close the through passage of the drill rod, while in the open condition the closure member may be spaced from the sealing surface to allow a medium, in particular a fluidised medium such as a fluid (which may be liquid or gas, for example drilling mud, or air) or suspension, to flow through the through passage.
16. A drill rod according to claim 15, in which the valve assembly comprises a guide for guiding the movement of the closure member.
17. A drill rod according to claims 15 or 16, in which the closure member is slideably moveable.
18. A drill rod according to any of claims 14 to 17, in which the valve assembly includes biasing means spring biasing the closure member toward the closed condition.*.* S.I
19. A drill rod according to claim 18, in which the biasing means comprises a spring.
20. A drill rod according to any of claims 14 to 19, in which the valve assembly includes an actuator which may move the closure member from the open condition to the closed condition, and/or between the open and closed conditions.
21. A drill rod according to claim 20, in which the actuator is mechanical, i.e. operable to move under the influence of mechanical force.
22. A drill rod according to claim 21, in which the actuator comprises a rod member which extends from the closure member.
23. A drill rod according to claim 22, in which the rod member extends along a longitudinal axis of the drill rod, away from the closure member and towards an end of the drill rod.
24. A drill rod according to any of claims 20 to 23 when dependent on claim 11, in which each of the first and second valve portions comprises a respective closure member and actuator.
25. A drill rod according to claim 24, in which the valve portions are arranged so that in use, when the ends of adjacent drill rods are connected, a surface of the actuator (e.g. a rod member) of the first valve portion of one drill rod may engage against a surface of the actuator (e.g. rod member) of the second valve portion of another drill rod.
26. According to a second aspect of the present invention there is provided a valve assembly for connecting adjacent drill rods, the valve assembly having a first condition in which the valve assembly is closed and a second condition in which the valve assembly is open, the valve assembly being moveable from the first condition to the second condition by connection of the adjacent drill rods.
27. A valve assembly according to claim 26 and any of claims 2 to 25. * * * S..
28. A drilling machine comprising a drill rod according to any of claims 1 to
29. A drilling machine according to claim 28, in which the drilling machine is a drilling rig.
30. A drilling rod. substantially as hereinbefore described and with reference to the. accompanying drawings.
31. A valve assembly essentially as hereinbefore described and with reference to the accompanying drawings.
32. A drilling machine substantially as hereinbefore described with reference to the accompanying drawings.
33. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims. * *S.....S S. * * * **. * S S..