Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B10/00—Drill bits
  • E21B10/26—Drill bits with leading portion, i.e. drill bits with a pilot cutter; Drill bits for enlarging the borehole, e.g. reamers
  • E21B10/28—Drill bits with leading portion, i.e. drill bits with a pilot cutter; Drill bits for enlarging the borehole, e.g. reamers with non-expansible roller cutters
  • E21B10/30—Longitudinal axis roller reamers, e.g. reamer stabilisers

Definitions

• the present invention relates to a roller reamer.
• 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.
• 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.
• 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.
• roller reamers 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.
• 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.
• a locking taper Moorse taper
• these techniques have been found to cause excessive pressure on the reamer body.
• 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 character
• 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.
• said reamer body attachment recess includes a recess adapted to receive said bolt.
• said dimensions of a locating taper are a slope of greater than 7 degrees.
• said roller reamer includes said roller reamer roller adapted to roll longitudinally about a shaft.
• roller reamer is attached to said reamer body by retaining the shaft of the roller reamer in the attachment block.
• said reamer body includes a central conduit for drilling fluid to be provided to a drill bit.
• said reamer body includes a plurality of circumferentially arranged spaced apart drilling mud conduits.
• said roller reamer roller is adapted to receive a plurality of cutting elements mounted circumferentially on said roller.
• said cutting elements are made of a material harder than steel and may not be of uniform size.
• roller reamer roller includes a narrowed forward end adapted to engage a ledge jutting from said bore hole wall.
• said narrowed end of said roller is adapted to receive said different sized cutting elements.
• 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.
• roller reamer includes a plurality of bearings adapted to allow the rotation of the roller reamer roller longitudinally about said shaft.
• 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.
• 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.
• 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
• Figure 5 illustrates in perspective view the reamer body with the reamer attached
• 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.
• 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.
• the bearings 30 are generally protected from debris, formed by the action of the roller reamerl4 engaging the bore hole wall, by sealing rings.
• 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.
• roller reamer 14 attached to a reamer body 12 at one end.
• 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.
• 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.
• 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.
• 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.
• FIG. 3 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.
• the bolt and 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).
• 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.

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• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Mining & Mineral Resources (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Earth Drilling (AREA)

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Cited By (3)

Citations (4)

• 2007
  • 2007-07-12 WO PCT/AU2007/000943 patent/WO2008006146A1/en active Application Filing
  • 2007-07-12 EP EP07763760A patent/EP2038509A1/de not_active Withdrawn

Patent Citations (4)

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