CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Application No. 62/258,869 filed on November 23, 2015 the disclosure of which is incorporated herein by reference for all purposes.

FIELD OF THE INVENTION

The present invention relates to a roller reamer and, more particularly, a sealed, frictionless bearing roller reamer.

BACKGROUND OF THE INVENTION

in the drilling of boreholes, e.g., oil and gas wells, over time due to drill bit wear, there occurs a gradual reduction in the gauge diameter of the borehole. Also, certain formation materials through which the borehole extends can swell which results in reduction of the borehole diameter after the drill bit has passed. Accordingly, it is often necessary when drilling a borehole to maintain or enlarge the diameter of the borehole with second and subsequent passes of cutting components connected in the drill string.

Reamers are commonly used in association with a drill bit to ensure that a borehole is drilled to a constant diameter or gauge. A roller-type reamer has cutting components rotatably mounted on a body and is commonly used in the drilling industry, one purpose being to ream the hole just behind the drill bit to maintain hole size. Further, a roller reamer can act as a stabilizer above the drill bit to stabilize the drill bit and drill string against the deviating tendencies encountered during drilling.

In many cases, the working environment of roller reamers is extremely harsh. Consequently, the components of the roller reamer frequently need servicing, repair, or replacement. As downtime for repair is costly, it is desirable to extend the working life of the components of the roller reamer to minimize repair downtime. Furthermore, it is desirable to be able to quickly and easily remove and replace the roller assemblies earned in the pockets in the roller reamer body.

SUMMARY OF THE INVENTION

In one aspect, the roller reamer of the present invention employs sealed, fnctionless bearing assemblies.

In another aspect, the present invention provides a roller reamer wherein the bearing assemblies are constantly lubricated during the drilling operations.

In yet a further aspect, the roller reamer of the present invention includes spiral blade stabilization over 360".

In yet another aspect of the present invention, the roller assemblies are locked into their respective pockets by a wedging lock.

In a further aspect of the present invention, there is disclosed and claimed a locking assembly for immobilizing a first member with respect to a second member having a recess or the like by wedging the first member in the recess.

These and further features and advantages of the present invention will become apparent from the following detailed description, wherein reference is made to the figures in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 js an elevational view of one embodiment of the roller reamer of the present invention.

Fig. 2 is a cross-sectional view taken along the lines 2—2 of Fig. 1.

Fig. 3 is a cross-sectional view taken along the lines 3— 3 of Fig. 1.

Fig. 4 is a cross-sectional view taken along the lines 4—4 of Fig. 1.

Fig. 5 is an elevational view, partly in section showing one of the roller assemblies of the roller reamer of the present invention.

Fig. 6 is a cross-sectional view taken along the lines 6—6 of Fig. 5.

Fig. 7 is an elevational, perspective view of a locking block according to one embodiment of the present invention.

Fig. 8 is a top view of the locking block shown in Fig. 7.

Fig. 9 is a bottom view of the locking block shown in Fig. 7.

Fig. 10 is an elevational side view of the locking block shown in Fig. 7. Fig. 11 is a sectional view taken along the lines 11—11 of Fig. 7.

Fig. 12 is an elevational view, partly in section, showing a method of securing the locking block of Fig. 7 to one embodiment of the roller reamer of the present invention.

Fig. 13 is a view similar to Fig. 12 but showing a method for removal of the locking block.

Fig. 14 is a cross-sectional view taken along lines 14—14 of Fig. 5.

Fig. 15 is a cross-sectional view taken along the lines 15— 15 of Fig. 14.

Fig. 16 is a partial, elevational view of the carbide button shown in Fig. 15.

Fig. 17 is an enlarged elevational view, partly in section, showing an assembly for rotatably mounting the rollers of the present invention in one embodiement of the roller reamer of the present invention.

Fig. 18 is an elevational view of another embodiment of the roller reamer of the present invention.

Fig. 19 is a cross-sectional view taken along the lines 19—19 of Fig. 18. Fig. 20 is a cross-sectional view taken along the lines 20—20 of Fig. 18. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Figs. 1-20 depict various roller reamer embodiments of the present invention as well as subassemblies and parts thereof. Like reference numerals are used to describe like elements albeit that such elements may appear in several of the Figures.

Turning first to Fig. 1 one embodiment of the roller reamer of the present invention is shown generally as 10. Roller reamer 10 comprises an elongate tubular body shown generally as 12 having a through bore 13, a first end 14, and a second end 16. As seen, first end 14 comprises a threaded box or female connection white second end 16 comprises a threaded pin or male connection, it will be understood that both ends 14 and 16 could comprise male connections or box connections and that other connecting structures could be employed, the goal being to connect roller reamer 10 into a drill string. There are first and second, axially spaced annular bands 16 and 20, respectively, formed on body 12. Bands 18 and 20 are provided with a plurality of spiral or helical wear strips 22 and 24, respectively, of a hard facing or banding substance such as tungsten carbide carried in a suitable matrix.

As can best be seen from Figs. 1 and 3, there are three roller assemblies shown generally as 26 which are rotatably journaled in a manner described hereafter in circumferentially spaced pockets formed in the outer wall of body 12 of roller reamer 10. Although, as shown, the three roller assemblies 26 are circumferentially spaced at 120°, it will be understood that the spacing could be varied if desired. Further, four or more roller assemblies 26 could be employed, albeit with diminishing returns.

With reference to Fig. 3 and as described more fully hereafter, each roller assembly 26 carries a plurality of circumferentially spaced tungsten carbide buttons 28. As seen with reference to Figs. 1-4, there are three circumferentially spaced, generally longitudinally extending channels shown generally as 30 having a first helical run 30A, a second, generally longitudinal run 30B, and a third helical run 30C. As seen in the embodiment shown in Figs. 1-4, helical runs 30A and 30C are in open communication with axial run 308, axial run 30B being generally parallel to the long axis of body 12. An axial run 30B is positioned between each set of adjacent roller assemblies 26 while helical runs 30A and 30C are formed in bands 18 and 20, respectively. Since the helical runs 30A and 30C are in open communication with the axial run 30B, there is formed a generally longitudinally extending flow channel along the length of body 12 whereby cuttings and other debris carried by the returning drill mud can flow upwardly in a well known manner.

Referring now to Fig. 5, there is shown a roller assembly 26 mounted in a pocket 40, pocket 40 having a center portion 40A, a first end portion 40B, and a second end portion 40C. Roller assembly 26 comprises a roller body shown generally as 42 having a center, largest diameter portion 42A, first and second intermediate diameter portions 426 extending from each axial end of portion 42A, and first and second smallest diameter portions 42C extending axially from portions 42B. As can be seen, each of portions 42A-42C are provided with tungsten carbide buttons 28. Buttons 28 are arrayed on central portion 42A of roller body 42 in a generally helical or spiral path, thereby ensuring 360° degree coverage in the borehole. It will be appreciated that the outermost surfaces of the buttons 28 on the central portions of 42A of the roller bodies 42 can be circumscribed by an imaginary cylinder which is theoretically the gauge diameter of the borehole.

Roller body 42 is rotatably journaled in first and second pillow blocks 50 and 52 received in portions 40B and 40C, respectively, of pocket 40. Each of pillow blocks 50 and 52 is provided with hard banding 50A and 52A, respectively, which is in a spiral pattern.

Referring now to Fig. 17, there is shown the details of how a roller assembly 26 is rotatably journaled in a pocket 40. While in the description which follows, reference will be made only to the assembly in connection with pillow block 50, it is to be understood that the pillow blocks in the other roller assemblies are of like construction. Pillow block 50 as seen with reference to Figs. 6 and 17 is a generally rectangular body having a top surface 53, a bottom surface 54, a first end surface 56, a second end surface 58, a first side surface 60, and a second side surface 62.

As best seen with reference to Fig. 12, first side surface 60 is at an obiique angle to bottom surface 54. As can also be seen in Fig. 12, top surface 53 has a slight radius of curvature so as to generally conform to the outer surface of the outer wall of body 12.

Pillow block 50 has a through bore extending from surface 56 to surface 58, the through bore comprising a threaded bore 70 opening through first end surface 56, a first passageway 72 of a first diameter, a second connecting passageway 74 of a second, larger diameter, a first radial bearing chamber 76, a thrust bearing chamber 78 and a second radial bearing chamber 80. There is a coupling 82 disposed between second end surface 58 of pillow block 50 and the first end 84 of roller body 42. In like manner, second pillow block 52 is interfaced to the second end 86 of roller body 42 by means of a second coupling 86.

Returning then to Fig. 17, first end 84 of roller body 42 has an annular groove 90 generally concentric with the through bore formed in pillow block 50. Coupling 82 has an axiaily extending projection 92 which is complementary to and received in groove 90. A series of cap bolts 94, only one of which is shown, are received through bores in coupling 82 and received in threaded bores 96 in second end face 58 of pillow block 52. Coupling 82 is also provided with a radially inwardly extending, annular groove 100, in which is received annular seal 102. In effect, coupling 82 in conjunction with first end 84 of roller body 42 form a labyrinth seal Positioned in radial bearing chamber 80 is a radial needle bearing cartridge 106 to keep out particulates in the drilling nozzle, the seal ring 102 preventing the ingress or egress of fluids into or out of the through bore. A needle roller thrust bearing assembly 108 is received in chamber 78. A second radial needle bearing cartridge 110 is received in chamber 76.

In effect, as seen from Fig. 17, roller body 42 has a first shaft shown generally as 110 which has a first axiaily extending portion 112, a second axiaily extending portion 114, portion 114 having a smaller O.D. than portion 112, and a third axiaily extending portion 116, portion 116 having a smaller I.D. than portion 114. There is thus formed a shoulder 112A on shaft 110 between portion 112 and portion 114 and a shoulder 114A between portion 114 and portion 116. it will be understood that there is a like second roller shaft extending from the second end 86 of roller body 42 and supported in pillow block 52 in the manner described above for pillow block 50.

Threadedly received in threaded bore 70 of pillow block 50 is a threaded fitting 120. Fitting 120 has an axially extending chamber 122 in which is reciprocally mounted a piston assembly 124. As can be seen in Fig. 17, there is a gap 130 between end surface 56 of pillow block and a first end wall 132 of portion 40B of pocket 40. There is a hexagonal hole 134 formed in the end of plug 120, hole 134 providing open communication between the exterior of roller reamer 10 via gap 130 and the interior of chamber 122. Thus, when the roller reamer is in use, fluid pressure in the borehole acts through gap 136 and hexagonal hole 134 against piston assembly 124.

Hexagonal hole 134 also serves as a wrench socket for the purpose of providing wrench flats for a wrench to thread plug 120 into the threaded portion of bore 70. A fluid reservoir for a lubricant 140 is formed by chamber 122 and passageways 74, 72 of the through bore. There is an injection port 142 extending through pillow block 50 for the injection of lubricant 140 into the reservoir and hence into contact with the various bearing assemblies disposed in pillow block 50. A threaded plug 144 is threadedly received in a threaded bore communicating with port 142.

It can thus be seen that the bearing assemblies 76, 78, and 80 are subject to positive pressure lubrication by lubricant 40 when roller reamer 10 is in a borehole and drilling is underway since external mud pressure acts on piston assembly 124 forcing lubricant into the bearing assemblies. As well, the labyrinth seal formed in part by coupling 82, as well as annular seal 102 serves to prevent the ingress of large particles into the through bore of pillow block 50, as well as preventing the loss of lubricant 140.

Referring now to Figs. 5-13, there is shown the details of a locking assembly for holding the pillow blocks in the pockets. As best seen with reference to Figs. 6, 12, and 13, portions 40B and 40C of pocket 40 have an axiaily extending bottom wail 170, an axially extending first side wall 172. and an axialiy extending second side wall 174.

As best seen with reference to Figs. 7-13, there is a lock block shown generally as 200, lock block 200 is generally wedge shaped and has a first side face 202, a second side face 204, a top face 206, and a bottom face 208. Lock block 200 has a plurality of laterally spaced pockets shown generally as 210 formed in second side face 204. Each of pockets 210 has an enlarged head portion 214 and a smaller diameter shank portion 216, which opens through bottom face 208. Head portin 214 is in open communication with a bore 218 which opens through top face 206. In general, pockets 210, when viewed in elevation, have the shape of a cap bolt. As can be seen from Fig. 6, cap bolts 230 can be positioned in the pockets 210 formed in side face 204.

Reference is now made particularly to Figs. 12 and 13 for a description of how lock block 200 can be used in conjunction with portion 40A of pocket 40 to secure a pillow block 50 in portion 40A of pocket 40. As seen, when pillow block 50 is positioned in portion 40A of pocket 40, side surface 62 is in engagement with wall 174, bottom surface 54 is in engagement with bottom wall 170 and side surface 60 is spaced from side wall 172. Received in that space is lock block 200. As seen in Fig. 12, with pillow block 50 and lock block 200 positioned in portion 40A of pocket 40, a cap bolt 230 is threaded into threaded bore 231 formed in the bottom wall 170 by clockwise rotation of wrench W extending through bore 218. As cap bolt 230 is threaded into bore 231, lock block 200 is forced in the direction of arrow A causing wedging engagement between angled side surface 60 of pillow block 50 and angled side face 202 of lock block 200. Since the angle of angled surface 60 and the angle of angled face 202 are supplemental to one another, movement of lock blocks 200 in the direction of arrow A applies a first force vector urging side surface 62 of pillow block 50 against side wall 174, a second force vector urging bottom face 204 of lock block 200 into engagement with bottom wall 54, and a third force vector urging side face 204 of lock block 200 into engagement with side wall 172. This unique lateral locking mechanism ensures that mere is no axial movement of the roller assembly including the pillow block 50. This has a great advantage in that close tolerances can be used particularly with respect to the joumaling of the roller shafts in the bearing cartridges. For example, this allows the use of a needle roller thrust bearing with no axial play as opposed to using a thrust washier which inherently needs and permits axial play. Accordingly, the time between change outs and replacing of the thrust bearings due to wear is greatly increased.

Referring now to Figs. 18-20 there is shown another embodiment of the roller reamer of the present invention. The roller reamer of Figs. 18-20, shown generally as 300. comprises an elongate tubular body 302 having a first end 304 forming a threaded box connection and a second end 306 forming a threaded pin connection. Carried on body 302 intermediate ends 304 and 306 is an annular band 308 having a plurality of helical or spiral strips of hard banding 310. As best seen in Fig. 19, there is a first array of three circumferentialiy disposed pockets 312 formed in the outer wall of body 302, a roller assembly shown generally as 314 being rotatably mounted in each of the pockets 312. Roller assemblies 314 are for all intents and purposes identical to the roller assemblies discussed above with respect to the embodiments shown in Figs, 1-17 and are mounted in the pockets 312 in the manner described above with respect to those embodiments. Thus, all features described above with respect to the roller assemblies of Figs. 1-17 can be found in roller assemblies 314.

As seen in Fig. 18, the first array of pockets 312 in roller assemblies 314 is positioned between the first end 304 of tubular member 302 and band 308. As can also be seen there is a first array of axiaily extending channels 316 formed in the outer wail of body 302, respective ones of channels 316 being disposed between adjacent pockets 312.

There is a second array of three circumferentialiy spaced pockets 320 disposed between second end 306 and band 308, there being a second array of roller assemblies 322, respective ones of roller assemblies 322 being received in respective ones of said pockets 320. As is the case with roller assemblies 314, roller assemblies 322 as to construction, mounting, lubrication, etc. are the same as described above with respect to the embodiments of Figs. 1-17.

There is also a second array of three axiaily extending, circumferentially spaced channels 324 formed in the outer wall of body 302. Channels 324, like channels 316 being generally parallel to the long axis of tubular body 302. As seen, the first array of pockets 312, roller assemblies 314, and channels 316 are circumferentially rotated or clocked relative to the second array of pockets 320, roller assemblies 322, and channels 324. This enhances stabilization in the borehole, virtually precluding any lateral movement during the drilling operation. In effect, there is substantially 360° borehole contact between the buttons of the roller assemblies and the wall of the borehole.

Formed in band 308 are a plurality of helical or spiral channels 326, channels 326 having a first or upper end 328 and a second or lower end 330. Respective ends 328 of helical channels 326 are in open communication with respective ones of channels 316 while respective ones of lower ends 330 are in open communication with respective ones of channels 324. In effect, communicating channels 316, 326, and 324 form a longitudinal flow path along the exterior of tubular body 302 allowing returning drill mud or other fluid carrying debris from the formation to the surface for disposal.

The roller reamer of the present invention has many advantages as compared to the prior art roller reamers. With respect first to stabilization, it is well known in the art that side to side or lateral motion of a stabilizer or reamer in a drill string causes excessive wear of the bottom hole assembly including measuring-while-drilling sensors, mud motors, etc. To overcome this lateral or side to side motion, the spiral "wings" formed between the spiral flow passages create a fanning effect leading to turbulent flow around the roller assemblies, thereby improving hole cleaning and maintaining of gauge diameter.

The radial or side loading locking assemblies of the present invention also provide an unexpected benefit in that a precise pre-load can be applied to the thrust bearing and once that desired preload is achieved, engagement of the lock block maintains that preload, meaning longer bearing life. This ability to use a precisely pre-loaded roller type thrust bearing as opposed to a thrust washer inherently increases the life expectancy of the roller assemblies.

As noted above, the roller body and the axial shafts for journaling the roller body are monolithic. Further, this monolithic structure permits an annular thrust bearing shoulder 114A to be formed on the shaft.

As was noted above, the hard surfacing and bore wall engaging buttons are all arranged in spiral patterns meaning that as the drill string is rotated, the spiral patterns of the hard surfacing and the buttons effectively act somewhat like a screw thread driving the bottom hole assembly forward, transferring weight to the bit, particularly in a deviated borehole when the bit has a horizontal or similar trajectory. The spiral patterns also ensure that the rollers will rotate when the roller reamer is in a sliding mode, i.e., in a curve or horizontal trajectory.

As can also be seen from the above description and in particular the manner of locking or holding the pillow blocks in the pockets, the present invention provides a unique locking system. Thus, if it was desired to lock a first member into a second member such that the first member could not move laterally or axially relative to the second member, the locking mechanism described above could be employed. Thus, the second member would have a pocket, recess, or the like, which had first and second spaced side walls and a bottom wall. The first member would have a first side surface, a second side surface, and a bottom surface, the second side surface being at an oblique angle to the bottom surface. A wedge shaped locking block has a first face, a laterally spaced second face, and a bottom face, the first face being at an oblique angle supplemental to the angle of the second side surface, the second face being engageable by the second wall. There would be a compression assembly which would force the bottom face of the wedge shaped locking block toward the bottom wall of the recess. Since the locking block is effectively trapped between the second side wall and the second surface, as the locking block is urged toward the bottom wall, the first side surface of the first member is urged towards the first wall of the second member. In like fashion, the second face of the locking block would be forced against the second wail of the recess. It will also be appreciated that instead of this precise arrangement, the second side face of the locking block and the second side wall could have angles supplemental to one another which would also result in a similar wedging action.

Another feature of the locking assembly of the present invention resides in the fact that there are three pockets as described above which, in elevation have the shape of a typical cap bolt. By having three pockets it can be seen that if it is desired to remove the pillow block or similar such member from the pocket in which it is locked, the middle cap screw can be unthreaded until the head of the cap screw abuts the shoulder formed between the bore which receives the wrench and the enlarged head of the pocket. Following this, the bolts on either side of the center bolt can be unthreaded which aids in locking block removal In this regard, if one of the end bolts is released first, there is a chance that the locking block can get cocked making it difficult to unthread the remaining bolts. In this regard, it must be remembered that since the locking block is wedge shaped, as soon as the bolts which hold the wedge shaped block in place are backed off, forces in the assembly try to urge the lock block out of wedging engagement.

Although specific embodiments of the invention have been described herein in some detail, this has been done solely for the purposes of explaining the various aspects of the invention, and is not intended to limit the scope of the invention as defined in the claims which follow. Those skilled in the art will understand that the embodiment shown and described is exemplary, and various other substitutions, alterations and modifications, including but not limited to those design alternatives specifically discussed herein, may be made in the practice of the invention without departing from its scope.