WO2008006146A1

WO2008006146A1 - A roller reamer

Info

Publication number: WO2008006146A1
Application number: PCT/AU2007/000943
Authority: WO
Inventors: Adel A. Bassal
Original assignee: Omni Oil Technologies
Priority date: 2006-07-12
Filing date: 2007-07-12
Publication date: 2008-01-17
Also published as: EP2038509A1

Abstract

An apparatus for the reaming of bore holes characterized in that it includes a reamer body including a plurality of recesses in said reamer body, each recess receiving a respective roller reamer therein said plurality of roller reamers being adapted to be attached to said reamer body circumferentially in spaced apart relation; and wherein each of said recesses on said reamer body includes reamer body attachment recess for a roller reamer roller to roll freely and a recess for a roller reamer to be attached to the reamer body at the forward and rearward ends of the roller reamer whereby said reamer body attachment recess for said roller reamer to be attached to the reamer body at the forward and rearward ends of the roller reamer includes an attachment block adapted to be received by the reamer body attachment recess and an attachment means adapted to be received by the reamer body attachment recess, and said method of receiving said attachment block and said attachment means in said reamer body attachment recess is characterised by a slight interference fit, in the form of a locating taper fit.

Description

A Roller Reamer

FIELD OF THE INVENTION

The present invention relates to a roller reamer. In particular, a sealed bearing rotary roller reamer, used, with respect to a drilling string, to enlarge the diameter of a bore hole, to compact and clean the walls of the bore hole and to stabilise the drilling string so that it remains in the centre of the bore hole.

BACKGROUND OF THE INVENTION

A roller reamer is used in conjunction with a drill bit and a drilling string, whereby the drilling string is adapted to rotate both the drill bit and a plurality of roller reamers attached to the drilling string. A roller reamer is used in the drilling process for the purpose of enlarging the diameter of the bore hole being drilled, compacting and cleaning the walls of the bore hole and stabilising the drilling string so that it is central to the bore hole and minimises the possibility of drilling at an incorrect angle.

Roller reamers are attached to a reamer body. Generally, roller reamers are equally spaced apart at 120 degree intervals on the reamer body, although other configurations are known. The reamer body is a long cylindrical structure adapted to closely fit the bore hole being drilled. Roller reamers are then attached onto the reamer body in specifically created longitudinal recesses and rotate about their longitudinal axis.

A roller reamer will typically possess; the ability to be attached to the reamer body recess, a roller, and a shaft for the roller to rotate about. Roller reamers also possess projections or cutters on the outer surface of the roller so as to engage the bore hole wall whilst rotating. The cutters generally comprise of a material harder than the steel bodied reamer, such as tungsten carbide, and are used to cut into to the bore hole wall to enlarge the diameter of the bore hole, compact the walls and produce a smooth bore hole wall.

Due to harsh operating conditions, roller reamers are subjected to stresses both as a result of vibrational shock and deterioration. Vibrational shock occurs due to the twisting and vibrating of the drilling string, to which the reamer body and plurality of roller reamers are attached. The roller reamer may typically fail at the point subjected to the most stress. This can occur at the outer edge of the shaft and at the point of attachment for the shaft, as these areas are subjected to the harsh operating conditions. The attachment means, or attachment block, is also subjected to high stresses. Other parts, such as the cutters used to engage the bore hole wall and bearings, suffer from wear and deterioration through use. This high probability of failure ensures that the design of a roller reamer must contain redundancy, especially with regard to the cutters and bearings and ensure that deteriorated parts can be replaced both easily and quickly.

As a result, a roller reamer requires a quick, efficient and reliable method of attachment to the reamer body. The roller reamer should also be designed to reduce the number of positions where excessive stresses can result in catastrophic failure. As some degree of failure is inevitable, due to the nature of the operating conditions and function of roller reamers, a quick method of attaching and detaching the reamer needs to be employed. This would increase efficiency and ensure that the drilling process is not halted.

The prior art has revealed means of retaining a roller reamer in a reamer body. These include having the roller reamer shaft tightly retained by a retaining block, which is generally welded in position and bolted to the reamer body. A bolt or pin is then used to tighten the end of the shaft against the block generally via the use of a locking taper (Morse taper) or wedge. However, these techniques have been found to cause excessive pressure on the reamer body. Also, the use of a locking taper can cause wear and damage to the reamer body. Techniques involving the use of multiple bolts or pins in order to attach the shaft to the retaining block will typically result in a longer length of time taken to remove these bolts and replace a worn roller reamer. Therefore it reduces the amount of time the roller reamer is being used effectively and reduces efficiency.

It is therefore an object of the present invention to improve the uptime of the roller reamer and overcome the aforementioned problems in order to provide the public with a useful alternative. SUMMARY OF THE INVENTION

Therefore in one form of the invention there is proposed an apparatus for the reaming of bore holes including: a reamer body including a plurality of recesses adapted to receive a plurality of roller reamers about the circumference of said reamer body; said plurality of roller reamers being adapted to be attached to said reamer body circumferentially in spaced apart relation; and wherein said recesses on said reamer body includes a recess for a roller reamer roller to roll freely and a recess for a roller reamer to be attached to the reamer body at the forward and rearward ends of the roller reamer whereby; said recess for said roller reamer to be attached to the reamer body at the forward and rearward ends of the roller reamer includes an attachment block adapted to be received by the reamer body attachment recess and an attachment means adapted to be received by the reamer body attachment recess; and said method of receiving said attachment block and said attachment means in said reamer body attachment recess is characterised by a slight interference fit, in the form of a locating taper fit.

Preferably said means of attaching the roller reamer to the reamer body at both the forward and rearward ends includes a bolt for fastening said shaft of said roller reamer and said attachment block to said reamer body.

Preferably said reamer body attachment recess includes a recess adapted to receive said bolt.

Preferably said dimensions of a locating taper are a slope of greater than 7 degrees. To avoid wedging and excessive stress. Preferably said roller reamer includes said roller reamer roller adapted to roll longitudinally about a shaft.

Preferably said roller reamer is attached to said reamer body by retaining the shaft of the roller reamer in the attachment block.

Preferably said reamer body includes a central conduit for drilling fluid to be provided to a drill bit.

Preferably said reamer body includes a plurality of circumferentially arranged spaced apart drilling mud conduits. Preferably said roller reamer roller is adapted to receive a plurality of cutting elements mounted circumferentially on said roller.

Preferably said cutting elements are made of a material harder than steel and may not be of uniform size.

Preferable said roller reamer roller includes a narrowed forward end adapted to engage a ledge jutting from said bore hole wall.

Preferably said narrowed end of said roller is adapted to receive said different sized cutting elements.

Preferably said means of attaching the roller reamer to the reamer body at both the forward and rearward ends further includes welded lugs to further retain said bolt and said attachments block in said respective recesses.

Preferable said roller reamer includes a plurality of bearings adapted to allow the rotation of the roller reamer roller longitudinally about said shaft.

Preferably said roller reamer includes a plurality of seals adapted to prevent debris from the reaming process from entering an aperture between said roller and said shaft.

Preferably said roller reamer includes a lubricant chamber adapted to prevent contact between the roller and the shaft and prevent debris from the reaming process from entering an aperture between said roller and said shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several implementations of the invention and, together with the description, serve to explain the advantages and principles of the invention. In the drawings:

Figure 1 illustrates a side sectional view of a roller reamer in accordance with the present invention attached to a reamer body, showing the upper half of the reamer body; Figure 2 illustrates a top view of the attaching means of a roller reamer;

Figure 3 illustrates a cross sectional view of the attaching means for a roller reamer taken on cross section A-A of fig 2;

Figure 4 illustrates the attachment of the roller reamer to the reamer body; and

Figure 5 illustrates in perspective view the reamer body with the reamer attached

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description of the invention refers to the accompanying drawings. Although the description includes exemplary embodiments, other embodiments are possible, and changes may be made to the embodiments described without departing from the spirit and scope of the invention.

The present invention refers to a rotary roller reamer, which rotates longitudinally along the bore hole in order to enlarge the diameter of the bore hole, compact and clean the walls of the bore hole and to stabilise the drilling string in the centre of the bore hole.

Figure 1 shows a reaming apparatus 10, with a substantially cylindrical reamer body 12 and a roller reamer 14. In this embodiment, three roller reamers 12 are fixed longitudinally to a reamer body 14 and equally spaced apart at 120 degree intervals. Figure 1 displays one of the three roller reamers 14 in a side sectional view of the upper half of the reamer body 12.

The reamer body 12 contains a central conduit 16 for the passage of drilling fluid and three recesses 18, equally spaced at 120 degree intervals on the circumference of the reamer body 12, adapted to receive the roller reamers 14. The recesses 18, of which one is shown in Figure 1, are shaped so as to allow the free rotation of the roller reamer 14 and the ability for it to be retained by providing an attachment recess 20 on each end of the recess 18. Attachment blocks 21 are adapted to be retained in the forward and rear attachment recesses 20 provided. The roller reamer 14 comprises a longitudinal shaft 22, which the roller 24 rotates about. The shaft 22 is secured to the attachment blocks 21, at both its forward and rearward ends, by the use of a bolt 26. The bolt 26 is secured in the bolt recess 28 and tightened. A plurality of bearings 30, mounted about the longitudinal shaft 22, allow for the roller 24 to longitudinally rotate smoothly and with less wear about the shaft 22. The bearings 30 are generally protected from debris, formed by the action of the roller reamerl4 engaging the bore hole wall, by sealing rings. To further promote the smooth longitudinal rotation of the roller 24 about the shaft 22, a lubricant chamber 31 encases the shaft 22 and provides an additional source of lubrication preventing the shaft from contacting the roller and preventing any further debris from entering this area.

The roller 14 also contains, on its outer surface, a plurality of recesses adapted to receive and mount a plurality of cutting elements 32. These cutting elements 32 are adapted to cut into the walls of the bore hole and enlarge its diameter, also the cutters 32 compact and clean the walls of the bore hole ensuring a smooth, consistently shaped bore hole. These functions require the cutting elements to be of a hard wearing substance, typically tungsten carbide or another substance harder than the steel roller 14. The roller 24 also contains the added feature of having a plurality of different sized cutting elements 34, mounted on an angled portion 36 of the roller so as to first engage a ledge or other obstruction that may exist on the bore hole wall being reamed. This feature reduces the severity of impact when the roller reamer strikes a ledge in the bore hole wall, reducing the instance of undue wear. Thus, further increasing the longevity of the roller reamer and the length of time it can be used without the need to replace any parts.

Shown in Figure 2, is a roller reamer 14 attached to a reamer body 12 at one end. It can be seen that the means of attachment comprises an attachment block 21, adapted to be contained in the attachment recess 20 and secured in position by a bolt 26. The bolt 26 is adapted to be retained in position by the bolt recess 28. Due to the extreme operating conditions, roller reamers are typically subject to high levels of wear and deterioration. Therefore, in order to ensure a high rate of reaming, it is important to keep the roller reamer in use in an effective working condition for as long as possible. Also, as the roller reamers provide a stabilising function to the drilling of a bore hole, it is important to maintain a high level of uptime so as to ensure a higher rate of penetration for the drilling process. To ensure the maximum amount of time the roller reamers are in use, the roller reamers need to be more resistant to deterioration and shock loading and possess the ability to be replaced quickly. The use of one large diameter bolt 26 to attach one end of the roller reamer 14 to the reamer body 12, allows for the quicker release and assembly than is possible with multiple bolt or pin systems. This is especially the case due to the forces and conditions the bolts or pins are subjected to throughout their lifespan. Also, the large diameter bolt 26, when used in relation to the bolt recess 28, is able to withstand the rotational forces and the shock loadings applied to the attachment position. Shock loadings are transmitted through the drilling string and can occur due to differences in the rock formation being drilled, whether any ledges are jutting out from the bore hole wall, or due to the rough handling of the drilling string during maintenance or use.

Shown in Figure 3 are the three equally spaced roller reamers 14 attached to a reamer body 12, with a central conduit 16 for the transport of drilling fluid to the drill bit, and three equally spaced mud conduits 29 adapted to assist with the removal of drilling mud and reaming debris. The attachment block 21 is shown in Figure 3 to be wedge shaped and the attachment recess 20 is adapted to receive the wedge shaped attachment block 21. It can also be seen that the bolt 26, used to secure the attachment block 21 into the recess 20 and the shaft 22 of the roller reamer 14, is adapted to be received by the bolt recess 28.

To ensure the attachment block 21 and bolt 26 are retained firmly in their respective recesses, the bolt and the block are held in position by an interference fit. The bolt and block are adapted to be received as a locating taper, which has a slope of 1 in 12.5 or 8 degrees. The locating taper is an improvement on the prior art as it allows for the easier release of the bolt 26 and block 21 so that a roller reamer 14 can be replaced quickly while still allowing a sufficiently firm fit. The prior art locking taper requires more force to remove the bolt or pin from the recess and a hammer is generally used. This is as the interference fit of a locating taper provides less force on the bolt or block being retained than a locking (Morse) taper (less than or equal to 7 degrees). Therefore, allowing the use of only one bolt 26, used at each end, to retain the roller reamer 14. A lesser force exerted on the bolt 26 and the block 21 allows the easier removal of the roller reamer for replacement and a lesser probability of the bolt failing due to the harsh forces it is subjected to. Also, due to the large forces exerted on the attachment means, the use of a locking taper can cause damage to the reamer body.

In addition to the locating taper, welding lugs 27 are used to provide an additional ability to retain the bolt 26 in its optimum position throughout the operating life span of a roller reamer 14.

Further advantages and improvements may very well be made to the present invention without deviating from its scope. Although the invention has been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope and spirit of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

In any claims that follow and in the summary of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprising" is used in the sense of "including", i.e. the features specified may be associated with further features in various embodiments of the invention.

Claims

1. An apparatus for the reaming of bore holes characterized in that it includes: a reamer body including a plurality of recesses in said reamer body, each recess receiving a respective roller reamer therein said plurality of roller reamers being adapted to be attached to said reamer body circumferentially in spaced apart relation; and wherein each of said recesses on said reamer body includes reamer body attachment recess for a roller reamer roller to roll freely and a recess for a roller reamer to be attached to the reamer body at the forward and rearward ends of the roller reamer whereby; said reamer body attachment recess for said roller reamer to be attached to the reamer body at the forward and rearward ends of the roller reamer includes an attachment block adapted to be received by the reamer body attachment recess and an attachment means adapted to be received by the reamer body attachment recess; and said method of receiving said attachment block and said attachment means in said reamer body attachment recess is characterised by a slight interference fit, in the form of a locating taper fit.

2. An apparatus for the reaming of bore holes according to claim 1 characterized in that said means of attaching the roller reamer to the reamer body at both the forward and rearward ends includes a bolt for fastening said shaft of said roller reamer and said attachment block to said reamer body.

3. An apparatus for the reaming of bore holes according to claim 2 characterized in that it said reamer body attachment recess includes a recess adapted to receive said bolt.

4 An apparatus for the reaming of bore holes according to claim 3 wherein said means of attaching the roller reamer to the reamer body at both the forward and rearward ends further includes welded lugs to further retain a bolt and said attachments block in said respective recesses.

5. An apparatus for the reaming of bore holes according to claim 1 reamer body attachment recess includes a locating taper are of slope of greater than 7 degrees.

6. An apparatus for the reaming of bore holes according to claim 1 wherein said roller reamer includes said roller reamer roller adapted to roll longitudinally about a shaft.

7. An apparatus for the reaming of bore holes according to claim 6 in which said reamer body includes a central conduit for drilling fluid to be provided to a drill bit.

8. An apparatus for the reaming of bore holes according to claim 6 wherein said reamer body includes a plurality of circumferentially arranged spaced apart drilling mud conduits conduit for drilling fluid to be provided to a drill bit. .

9. An apparatus for the reaming of bore holes according to claim 6 in which said roller reamer roller is adapted to receive a plurality of cutting elements mounted circumferentially on said roller.

10. An apparatus for the reaming of bore holes according to claim 9, in which said cutting elements are made of a material harder than steel and may not be of uniform size.

11. An apparatus for the reaming of bore holes according to claim 10 wherein said roller reamer roller includes a narrowed forward end adapted to engage a ledge jutting from said bore hole wall.

12. An apparatus for the reaming of bore holes according to claim 11 in which said narrowed end of said roller is adapted to receive said different sized cutting elements.

13. An apparatus for the reaming of bore holes according to claim 12 in which said roller reamer includes a plurality of bearings adapted to allow the rotation of the roller reamer roller longitudinally about said shaft.

14. An apparatus for the reaming of bore holes according to claim 13in whcih said roller reamer includes a plurality of seals adapted to prevent debris from the reaming process from entering an aperture between said roller and said shaft.

15. An apparatus for the reaming of bore holes according to claim 14 in which said roller reamer further includes a lubricant chamber adapted to prevent contact between the roller and the shaft and prevent debris from the reaming process from entering an aperture between said roller and said shaft.