Wear-resistant support assembly for under-reaming tool

Abstract

A wear resistant support assembly is provided comprising a wear pad arranged on top of a support plate, wherein the support plate has a lower surface for connection to a backreaming tool and both the wear pad and the support plate have at least one hole for receiving a bolt to connect the wear pad to the support plate. A backreaming tool for backreaming operations is also provided comprising: a reamer head having a body; a plurality of rollers connected to the body using a holder; a nose or drive rod connected to the body; and at least one wear resistant support assembly, wherein each support plate is directly connected to the backreaming tool and each wear pad is bolted radially or perpendicularly to each support plate.

Description

Technical Field

[0001] This invention relates to wear-resistant support components for reverse well boring tools, and more particularly to wear-resistant support components for reamer heads and drive rods. Background Technology

[0002] Raising borehole tools include a reamer head, which is used to drill a raising borehole by reaming the pilot hole to the desired final diameter. The reamer head typically consists of multiple cutters arranged in a circular pattern on a body and rotating as the reamer head feeds upwards, thus fracturing the rock around the pilot hole. During drilling, a drive rod or bull nose is positioned in the pilot hole. The pilot hole can be drilled simultaneously with the raising borehole drilling (in the case of blind boreholes) or pre-drilled.

[0003] Traditionally, reamer heads have wear pads integrated or welded to one or more parts of the reamer head body to help stabilize the reamer head during drilling and protect it from excessive wear in exposed areas. These wear pads are typically made of mild steel with a surface-hardened coating on the exposed outer surface. The problem is that when the wear pads need replacing, the only way to do so is to send the entire reamer head to the workshop to remove the used wear pads and re-weld them on or weld on new ones. This is time-consuming, often taking several days, and not very convenient.

[0004] Therefore, the problem to be solved is how to provide wear-resistant pads that can be easily replaced near the drilling rig, thereby reducing downtime during drilling operations, while still providing effective wear protection and improved stability for the reverse borehole tool, and these wear-resistant pads are firmly held in place so that they do not easily shift when subjected to drilling forces. Summary of the Invention

[0005] The objective of this invention is to provide a novel and improved wear pad design for reverse borehole tools. Specifically, the objective is to provide a wear pad design that can be easily replaced directly by the drilling rig. Another objective is to provide wear pads that improve the stability of drilling operations and are securely held in place so that they are not easily removed when forces are applied from the drill bit.

[0006] This objective is achieved by providing a wear-resistant support assembly comprising a wear-resistant pad disposed on top of a support plate, wherein the support plate has a lower surface for connection to a reverse borehole tool and at least one hole for receiving bolts to connect the wear-resistant pad to the support plate. Preferably, the lower surface of the support plate is curved, but it can also be flat. The at least one hole should exist in both the wear-resistant pad and the support plate, and these holes should be aligned so that the bolts can connect the two parts radially or vertically relative to the lower surface of the wear-resistant pad. Advantageously, this design means that the wear-resistant pad can be easily replaced near the drilling rig. The inclusion of the support plate and the radial or vertical (or vertical) bolt connection relative to the lower surface of the wear-resistant pad mean that the wear-resistant pad is securely held in place so that it is not easily removed when drilling forces are applied. This design also improves the stability of the reamer head, especially when a larger wear-resistant pad is fitted, thereby reducing wear on the reverse borehole tool and increasing its service life.

[0007] Preferably, there are more than two holes, and more preferably four holes. Advantageously, this means that more bolts can be used to connect the wear pad to the support plate, and therefore, because the force from the drill is distributed among more contact points, the wear pad is more firmly held to the support plate.

[0008] Alternatively, the holes can have two diameters, with the larger diameter hole closer to the upper surface of the support plate and the smaller diameter hole closer to the lower surface of the support plate. Advantageously, this means that the bolts can be countersunk into the wear pads and are therefore more protected from wear.

[0009] Preferably, the wear-resistant support assembly further includes at least one bolt, more preferably more than two bolts. More preferably, each wear-resistant pad is bolted to each support plate using more than two bolts, such as four bolts, for example, one bolt at each corner of the wear-resistant pad. The bolts project radially or vertically into the wear-resistant support assembly relative to the lower surface of the wear-resistant pad. Advantageously, this means that the wear-resistant pad is more firmly held to the support plate because the drilling force is distributed among more contact points.

[0010] Optionally, the support plate has a stop bolt, preferably positioned on the rear side of the support plate in the direction of rotation when connected to a reverse boring tool. Alternatively, the stop bolt may be located on the front side in the direction of rotation, or on both the rear and front sides in the direction of rotation. Advantageously, the stop bolt provides further support to the wear pad against rotational forces from drilling operations, thus ensuring that the wear pad is rigidly held in place.

[0011] Preferably, the support plate includes a rear end step for securing the wear pad to the support plate. Advantageously, including the step at the rear end of the support plate ensures that the wear pad is rigidly held to the support plate by providing support against forces applied from the forward drilling direction.

[0012] Optionally, the support plate includes side steps for securing the wear pad (22) to the support plate, preferably on the rear side of the support plate in the direction of rotation when connected to a reverse boring tool. Alternatively, the side steps may be positioned on the front side of the support plate in the direction of rotation or on both sides of the support plate. Advantageously, including side steps on the support plate ensures that the wear pad is securely held to the support plate by providing support against forces exerted from the rotation of the reamer head.

[0013] Alternatively, the rear end step and / or side steps are milled into the support plate. In other words, the support plate is made from a single piece. The advantage of this is that it maintains the strength of the support plate.

[0014] Alternatively, the rear step is bolted or welded to the support plate. In other words, the support plate is made of two parts joined together. The advantage of this design is that the step is easier to replace in the field.

[0015] Optionally, a key is present on the support plate. Advantageously, the key reduces the stress on the bolts and ensures that the support plate and the wear pad are firmly held together, thereby reducing the risk that the wear pad may be dislodged during drilling operations.

[0016] Alternatively, the bonds are press-fitted into the appropriate positions. Advantageously, this achieves a simple construction.

[0017] Alternatively, the key is bolted into place. Advantageously, this means the key is securely held in place.

[0018] Preferably, the one or more bolts are countersunk into the wear-resistant pad. Advantageously, this means that the bolts will experience less wear and therefore will last longer.

[0019] Alternatively, both the upper surface of the support plate and the lower surface of the wear pad are flat. Alternatively, both the upper surface of the support plate and the lower surface of the wear pad are convex. The choice between a flat or convex geometry will depend on manufacturing capabilities and the design of the reamer tip.

[0020] Preferably, the wear-resistant pad is surface-hardened, for example, with tungsten carbide. Advantageously, this will improve the wear resistance of the wear-resistant pad.

[0021] Another aspect of the invention relates to a reverse boring tool for reverse boring operations, comprising: a reamer head having a body; a plurality of cutters connected to the body using retainers; a nose or drive rod connected to the body; and at least one wear-resistant support assembly, wherein each support plate is directly connected to the reverse boring tool, and each wear pad is bolted to each support plate, preferably in a radial or vertical direction relative to the lower surface of the wear pad. Advantageously, this design means that the wear pad can be easily replaced near the drilling rig. The inclusion of support plates and the radial or vertical direction of the bolted connections mean that the wear pad is securely held in place so that it is not easily removed when drilling forces are applied. This design also improves the stability of the reamer head, especially when a larger wear pad is fitted, thereby reducing wear on the reverse boring tool and increasing its service life.

[0022] The body of the reamer head may have a nose, or be connected to a nose, or be connected to a drive rod. If the body of the reamer head has a nose or is connected to a nose, the nose may have a threaded connection for attachment to a stabilizing tube or a guide drill bit, or it may be a bottom plug forming the front end of the reamer head.

[0023] In one embodiment, at least one wear-resistant support component is positioned on the body of the reamer head. Advantageously, this provides wear protection for the body of the reamer head and stability for drilling operations.

[0024] In another embodiment, at least one wear-resistant support component is positioned on the nose of the reamer tip. Advantageously, this provides wear protection for the nose of the reamer tip.

[0025] In another embodiment, at least one wear-resistant support component is positioned on the drive rod. Advantageously, this provides wear protection for the drive rod.

[0026] The wear-resistant support assembly may be positioned only on the body of the reamer head; or only on the nose or drive rod of the reamer head; or on both the body of the reamer head and the nose or drive rod of the reamer head.

[0027] Alternatively, the nose of the reamer head is integrated with the body of the reamer head. Alternatively, depending on the design of the reamer head, the nose can be detached from the body. Attached Figure Description

[0028] Specific embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings, wherein:

[0029] Figure 1 This is a perspective view of a reverse well boring tool, which has a reamer head with two hobs and a wear-resistant support assembly positioned on the body of the reamer head.

[0030] Figure 2 This is a perspective view of a reverse well boring tool, which has a reamer head with three hobs and a wear-resistant support assembly positioned on the body of the reamer head.

[0031] Figure 3 This is a perspective view of a reverse borehole boring tool, which has a reamer head with two hobs and a wear-resistant support assembly positioned on the nose of the reamer head.

[0032] Figure 4 This is a perspective view of a reverse well boring tool, which has a reamer head connected to a drive rod and a wear-resistant support assembly positioned on the drive rod.

[0033] Figure 5 This is a perspective view of the wear-resistant pad.

[0034] Figure 6 It is a perspective view of the support plate with the rear step.

[0035] Figure 7 This is a perspective view of an embodiment of the present invention, wherein the support plate has a rear step and a stop bolt.

[0036] Figure 8 This is a perspective view of an embodiment of the present invention, wherein the support plate has a rear end step and a side step.

[0037] Figure 9 This is a perspective view of an embodiment of the present invention, wherein the support plate has a key.

[0038] Figure 10 This is a perspective view of an embodiment of the present invention, wherein the support plate has a flat upper surface. Detailed Implementation

[0039] Figure 1 A reverse borehole boring tool 6 is shown, comprising: a reamer head 8 including a body 16; a plurality of hobs 14 rotatably mounted on the body 16 by a holder 15 (also referred to as a fastener, tool holder, or saddle); and a nose 12 (optionally fitted with a bottom plug) having threaded connections for attachment to a stabilizing tube and a guide bit. The holder 15 is mounted or integrated into the body 16. The nose 12 may be integrated with the body 16 or may be a separate attachable part.

[0040] The nose 12 can be a bottom plug and form the front end of the reamer head 8, or it can have a threaded connection for attachment to a stabilizing tube and a guide drill bit. Alternatively, as Figure 4 As shown, the drive rod 10 can be attached to the body 16 of the reamer head 8, rather than the nose 12.

[0041] At least one support plate 20 is attached to the reverse bore tool 6 in the area requiring wear protection. The support plate 20 has a lower surface 46 for radial connection to the reverse bore tool 6, which is preferably curved but can also be flat. Radial means perpendicular to the centerline 56 of the reverse bore tool 6. Preferably, the support plate 20 is welded to the reverse bore tool 6. Alternatively, the support plate 20 can be bolted to or secured to the reverse bore tool 6 in any other suitable manner. The support plate 20 can be fitted to the body 16 and / or nose 12 of the reamer head 16, and / or can be fitted to the drive rod 10 or any other location requiring wear protection. Next, a wear pad 22 is bolted radially or vertically to the support plate 20 relative to the lower surface 40 of the wear pad 22 using a plurality of bolts 24. Preferably, more than two bolts 24 are used, such as four bolts 24. For example, a bolt 24 may be present in each of the corners of the wear-resistant pad 22. The support plate 20 and the wear-resistant pad 22 together form the wear-resistant support assembly 4. Figure 5 The wear pad 22 is shown in more detail. Typically, the support plate 20 and the wear pad 22 have a rectangular shape, but they can be any other suitable shape, and have holes 36 drilled therein to receive bolts 24. Bolts 24 can extend through the wear pad 22 into the support plate 20, or they can extend through the support plate 20 into the body 16 or nose 12 of the reamer head 8 or into the drive rod 10. The wear pad 22 has a lower surface 40 that contacts the upper surface 38 on the support plate, and an upper surface 42 exposed to the rock being drilled. The holes 36 protrude vertically or radially relative to the lower surface 40 of the wear pad 22. The wear pad 22 is made of a wear-resistant material; for example, the wear pad 22 can be made of mild steel or hard steel. Preferably, the upper surface 42 of the wear pad is surface-hardened, for example, with tungsten carbide or any other suitable wear-resistant material. Alternatively, carbide inserts can be added to the wear pads 22 to improve their wear resistance. Preferably, the bolts 24 are countersunk into the wear pads 22 to reduce their wear. This can be achieved by drilling holes 36 in the wear pads 22 to receive the bolts 24, the holes 36 having two diameters, with the larger diameter hole closer to the upper surface 42 and the smaller diameter hole closer to the lower surface 40. The area of ​​the wear pads 22 can be increased to any suitable size for the specific reverse borehole tool 6 to provide additional wear protection and stability.

[0042] The wear-resistant support component 4 can be attached to any part of the reverse well boring tool 6 that requires wear protection. Figure 1An example is shown where the raise boring tool 6 is a slot raiser, and where a wear-resistant support assembly 4 is attached to the body 16 of the reamer head 8, which has two cutters 14 and a nose 12 with a threaded connection. When only two cutters 14 are present, the wear-resistant support assembly 4 is particularly important for improving the stability of the drilling operation. Figure 2 An example of a slotted riser rig is shown, in which a wear-resistant support assembly 4 is attached to the body 16 of a cutter head 8, which has three rollers 14 and a nose 12 with a threaded connection. Figure 3 An example of a slotted riser rig is shown, which has two cutter heads 14, a nose 12 which is a bottom plug, and wherein a wear pad 22 and a support plate 20 are attached to the nose 12 of the cutter head 8. Figure 4 An example of a reverse borehole boring tool 6 is shown, wherein a reamer head 8 is attached to a drive rod 10, and wherein a wear-resistant pad 22 and a support plate 20 are attached to the drive rod 10. In this configuration, the drive rod 10 connects the reamer head 8 to a drilling rig (not shown) and assists in stabilizing the drilling operation. It should be understood that the invention can be applied to any other type of reverse borehole boring tool 6 or device, and the wear-resistant support assembly 4 can be positioned on any part of the reamer head 8 or drive rod 10 that requires wear protection and / or stability.

[0043] Figure 6 The support plate 20 is shown to have a rear end step 28 positioned to absorb forces from the forward drilling direction and to hold the wear pad 22 rigidly in place. The rear end step 28 is positioned on the opposite side of the support plate 20 axially compared to the hob 14. The rear end step 28 can be milled into the support plate 20 so that the support plate 20 is a single-piece body. Alternatively, the rear end step 28 can be bolted or welded to the support plate 20 so that the support plate 20 is a two-piece or multi-piece body. The step is a section of the support plate 20 with increased thickness, having a first side 50 perpendicular to the upper surface 42 for abutting the wear pad 22, and a second side 52 parallel to the upper surface 42 and protruding relative to it.

[0044] Figure 7 The stop bolt 32 is shown, which can also be fixed to the rear side of the support plate 20 in the direction of rotation so that the wear pad 22 can be pressed against it. The rear side in the direction of rotation is the side opposite to the side that first contacts the rock when the reamer head 8 rotates. The stop bolt 32 acts as a support for the wear pad 22 to absorb some of the rotational force applied from the drilling operation and helps to keep the wear pad 22 rigidly held in place. The rear step 28 and the stop bolt 32 can be used alone or in combination.

[0045] Figure 8An alternative embodiment of the support plate 20 is shown, in which the stop bolt 32 is replaced by a side step 30. The side step 30 can be used in combination with the rear step 28 or alone. The side step 30 is positioned on the rear side of the support plate 20 in the direction of rotation, in other words, on the side of the support plate 20 that first contacts the rock when the reamer head 8 rotates. Alternatively, the side step 30 can be positioned on the front side of the support plate 20 in the direction of rotation. Two side steps 30 may also be present on the support plate 20, one on each side of the wear pad 22, in other words, one on the rear side and one on the front side in the direction of rotation, so that the wear pad 22 is supported in both rotational directions. The side steps 30 can be welded, milled, or bolted into place. The side steps 30 can be used alone or in combination with the rear step 28.

[0046] The step is a section of the support plate 20 with increased thickness, which has a first side 50 perpendicular to the upper surface 42 for adjacent to the wear pad 22, and a raised side 52 parallel to the upper surface 42.

[0047] Figure 9 An alternative embodiment is shown, in which key 34 is positioned on support plate 20. Key 34 is fitted into a groove between wear pad 22 and support plate 20 to relieve stress on bolt 24. Key 34 can be any suitable shape, such as pin-shaped, rectangular, or crescent-shaped. Key 34 can be pressed into place or bolted into place with small screws. Key 34 can be countersunk into a recess on the lower surface 40 of wear pad 22. Key 34 can be used alone or in combination with any of the embodiments disclosed above.

[0048] like Figures 6 to 9 As shown, the upper surface 38 of the support plate 20 and the lower surface 40 of the wear-resistant pad 22 that are pressed against each other can both be convex or curved.

[0049] Figure 10 An alternative embodiment is shown in which the upper surface 38 of the support plate 20 and the lower surface 40 of the wear pad 22 are both flat and are assembled such that they are parallel to each other.

Claims

1. A wear-resistant support assembly (4) associated with a hob of a reverse bore tool (6), the wear-resistant support assembly including a wear-resistant pad (22) disposed on the top of a support plate (20), wherein the support plate (20) has a lower surface (46) for connection to the reverse bore tool (6), wherein the support plate (20) includes a rear end step (28) for securing the wear-resistant pad (22) to the support plate (20), and the wear-resistant pad is rigidly held to the support plate and arranged to provide support against forces exerted from the forward drilling direction by the hob, the rear end step being positioned on the axially opposite side of the support plate compared to the hob, wherein, The wear-resistant support assembly is arranged between the roller cutters on the body of the reverse well boring tool.

2. The wear-resistant support assembly (4) according to claim 1, wherein both the wear-resistant pad (22) and the support plate (20) have at least one hole (36) for receiving a bolt to connect the wear-resistant pad (22) to the support plate (20).

3. The wear-resistant support assembly (4) according to claim 1, wherein the support plate (20) has a stop bolt (32) for fixing the wear-resistant pad (22) to the support plate (20).

4. The wear-resistant support assembly (4) according to claim 1, wherein the support plate (20) includes a side step (30) for fixing the wear-resistant pad (22) to the support plate (20).

5. The wear-resistant support assembly (4) according to claim 1 further includes a key (34) located on the support plate (20).

6. The wear-resistant support assembly (4) according to claim 2, wherein the at least one hole (36) comprises a plurality of two holes, each hole for receiving a bolt.

7. The wear-resistant support assembly (4) according to claim 2, wherein the at least one hole (36) has two diameters, wherein the hole with a larger diameter is closer to the upper surface (42) of the support plate (20) and the hole with a smaller diameter is closer to the lower surface (40) of the wear-resistant pad (22).

8. The wear-resistant support assembly (4) according to claim 1, wherein both the upper surface (38) of the support plate (20) and the lower surface (40) of the wear-resistant pad (22) are flat.

9. The wear-resistant support assembly (4) according to claim 1, wherein both the upper surface (38) of the support plate (20) and the lower surface (40) of the wear-resistant pad (22) are convex.

10. The wear-resistant support assembly (4) according to claim 1, wherein the wear-resistant pad (22) is surface-hardened with tungsten carbide.

11. A reverse well boring tool (6) for reverse well boring operations, comprising: Reamer head (8), the reamer head (8) has a body (16); Multiple hobs (14) are connected to the body (16) using retainers (15). The nose (12) or drive rod (10) connected to the body (16); and At least one wear-resistant support component (4) according to claim 1; Each support plate (20) is directly connected to the reverse well boring tool (6), and each wear pad (22) is bolted to each support plate (20).

12. The reverse well boring tool (6) according to claim 11, wherein at least one wear-resistant support component (4) is positioned on the nose (12) of the reamer head (8).

13. The reverse well boring tool (6) according to claim 11, wherein at least one wear-resistant support assembly (4) is positioned on the drive rod (10).

14. The reverse borehole tool (6) according to claim 11, wherein the nose (12) is integrated with the body (16).

15. The reverse well boring tool (6) according to claim 11, wherein the nose (12) is detachable from the body (16).

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