The present description relates, in general to systems and techniques for focusing wear in a vibrational dampener or shock absorber on replaceable components. More specifically, the present disclosure relates to systems and methods including a vibrational dampener or shock absorber for rotary drilling.
In various types of drilling operations, the drill bit is forced downward under pressure while being rotated in order to penetrate earthen formations. These drilling operations can require the application of relatively high downward force to the drill bit as well as relatively high torque to turn the drill bit. One example includes a large drilling rig to which is attached a rotary drive mechanism. Typically, the drill's rotary drive is capable of being raised and lowered along a substantially vertical axis directly above the formation to be drilled. Additionally, a length of drill pipe or drill string is connected to the rotary drive so as to extend downwardly therefrom in a substantially vertical direction. A drill bit is secured to the downward end of the drill pipe.
The drilling rig's rotary drive is activated to rotate both the drill pipe and the drill bit at the suitable speed. Then, the rotary drive, together with the drill pipe and drill bit, is lowered so that the drill bit contacts the surface of the formation to be drilled. Downward pressure is then continuously applied to the rotating drill pipe and bit to force the drill bit to cut downwardly into the formation. As the drilling operation occurs, air is forced through the interior of the rotary drive head, drill pipe, and through the drill bit, thereby forcing cuttings out of the hole and maintaining a clear surface upon which the drill bit may operate. When the drilled hole is deep enough to accommodate the first length of drill pipe, the drill's rotary drive is disconnected from the drill pipe and raised to its original position. A second length of drill pipe is then connected between the rotary drive and the first length of drill pipe. The rotary drive is then activated and the drilling operations are continued. This procedure is repeated until a suitable hole depth is achieved.
In order to reduce problems associated with vibration and shock to the drilling apparatus, various devices have been employed to dampen vibrations and absorb torsional forces during the operation of the rotary drill. These devices typically comprise a force absorbing apparatus which is connected between the drill machine's rotary drive head and the drill pipe. In some instances, the force absorbing device includes some type of resilient, or elastomeric, material which absorbs the vibrations and shocks, thereby dissipating the undesirable energy associated with the drilling operation.
Vibration dampeners or shock absorbers have been characterized by short operating lives. Some designs use an elastomeric cushion to absorb the vibrational effects of the drilling process, combined with positive stops that limit deflection of the elastomeric cushion. While effective, these products have a relatively short wear life. As the shock absorbing elastomeric cushion wears, the positive stops are subjected to increased forces. This may wear or damage the shock absorber in any of a number of locations. Damaged shock absorbers require removal from the drill string and replacement, creating work stoppages. In some instances, the shock absorber may be repaired instead of replaced. If the shock absorber is eligible for repair and continued use, it must be serviced. In some instances, this can require a complicated disassembly process.
It is therefore desirable to have predictable wear on the shock absorber, and to make the shock absorber or components of the shock absorber easy to replace. Use of a softer sacrificial material for the lugs will cause the lugs to wear while preserving the housing when the lugs come into contact with the positive stops of the housing. When the shock absorber is serviced, the lugs and elastomeric element should be easily replaceable while keeping the shock absorber attached to the drive motor and drill string. The ability to know what part of the product will wear and the ability to service the product without removing it from the rig will allow for faster and more efficient repairs.
Some exemplary aspects of the present disclosure are directed to a shock absorber system that includes a drive plate having a plurality of removable lugs. The drive plate may be connectable to a rotary drive shaft. The shock absorber may also include a driven plate connectable to a rotary driven shaft. A housing may be fixedly secured to either of the drive plate and the driven plate. The housing may have an outer wall forming a hollow center portion and a plurality of openings extending through the outer wall to the hollow center portion. Each opening of the plurality of openings may include first and second positive stops formed thereon. An elastomeric member may be disposed in the housing between the drive plate and the driven plate. The elastomeric member is configured to absorb vibration from one of the drive plate and the driven plate. Each removable lug of the plurality of removable lugs may have first and second striking faces at a radially distal edge and on circumferentially opposing sides.
In another exemplary aspect, the present disclosure may be directed to a shock absorber system that includes a drive plate including a plurality of removable lugs and a driven plate that is connectable to a rotary driven shaft. A housing may be fixedly secured to either the drive plate and the driven plate. The housing may have an outer wall forming a hollow center portion, and a plurality of openings extending through the outer wall to the hollow center portion. Each opening of the plurality of openings may have first and second positive stops, and the removable lugs extend at least partially through the openings. The lugs may be configured to selectively engage against opposing sides of the openings in a manner that limits an amount of rotation of the drive plate relative to the driven plate. The removable lugs may be removable and replaceable from the drive plate through the openings. The shock absorber may further include an elastomeric member disposed in the housing between the drive plate and the driven plate. The elastomeric member may be configured to absorb vibration from the drive or driven plates.
In yet another exemplary aspect, the present disclosure is directed to a method of repairing a shock absorber disposed between a drill string and a top drive. The method may include removing a drive plate, which has a removable lug, from an elastomeric element that is disposed in a hollow housing. The hollow housing may have a plurality of openings formed therein, and the removable lug may extend at least partially through one opening of the plurality of openings. The method may also include radially removing the removable lug from the drive plate through the one opening of the plurality of openings. The method may also include radially inserting a replacement lug through the one opening of the plurality of openings. The replacement lug may extend at least partially through the one opening. The method may further include attaching the drive plate to the elastomeric element in the housing.
The detailed description set forth below, in connection with the appended drawings, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details.
The present disclosure describes shock absorbing systems and methods for absorbing shock or dampening vibrations in a drill string. Some implementations include removable lugs designed to absorb wear on the shock absorbing system. Because of their design, the lugs may wear faster than other components of the shock absorbing system. In some implementations, these lugs may be removed and replaced, without a need to remove or replace the entire shock absorbing system. In some implementations, the shock absorbing system is used to manage torque on a drive shaft, which may be a rotary drive shaft, of a rotary drilling rig used in well drilling or mining.
Depending on the implementation, the lugs may be accessible through access windows formed in an outer housing that permit a user to replace the lugs in a minimal amount of time. In some implementations, the lugs are sized, shaped, and formed of materials that promote long life, but directed wear. Because of the directed wear, and the accessibility to the replaceable lugs, the shock absorbing system can have a long useful life with minimal rig downtime. This in turn leads to greater drilling efficiencies and increased profitability.
The shock absorbing system can be an important part of a drilling rig because it affords some protection to the expensive driving elements of the rig, such as a top drive. The shock absorbing system may be disposed between and may separate a drive shaft from a driven shaft, which may be a rotary driven shaft. During use, when the drill bit jams or snags, rotation of the driven shaft may slow or stop. The drive shaft may still turn, however, and the slowing of the driven shaft may result in high torque on the drive shaft. Some of this force or torque is absorbed by the shock absorbing system. For example, the shock absorbing system may include an annular body of resilient material that twists or deforms under load, thereby reducing the shock which is communicated to the drive shaft by the driven shaft. When the torque exerted on the annular body of resilient material reaches a predetermined amount, the resilient annular body rotates enough so that the side surfaces, or strike faces, of the lugs contact or engage against a housing that may prevent additional relative rotation of the driven shaft and the drive shaft, thereby avoiding additional torque from being placed on the elastomeric annular body. This prevents the elastomeric member from being exposed to an excessive torque which could potentially damage or weaken it.
In order to prevent the additional relative rotation, the housing may include windows. These windows provide a predetermined limit to the rotational movement as described above, and also provide a predetermined limit to the upward extension of the elastomeric member when the drill string is lifted from a hole. The drill string is lifted by applying lifting force to the drive shaft, which applies lifting force to the drive plate and causes the elastomeric member to stretch. The drive side of the window on the annular housing is above the lug inserts. When the elastomeric member stretches a predetermined amount, the lug inserts on the drive plate contact the drive side of the window, limiting the upward travel of the drive plate and preventing further stretching of the elastomeric member, thereby extending the life of the elastomeric member.
The drill string 104 is connected to a top drive 106 via a shock absorber 108. The drill string 104 terminates at a drill bit 110. The top drive 106 provides rotary power to the drill bit 110 through the drill string 104. The shock absorber 108 insulates the top drive 106 from at least some of the vibration and shock transmitted through the drill string 104 while the drilling rig 100 is in operation, thereby reducing wear on the top drive 106.
The drilling rig 100 in the example shown is or includes a land-based drilling rig. However, one or more aspects of the present disclosure are applicable or readily adaptable to any type of drilling rig, such as jack-up rigs, semisubmersibles, drill ships, coil tubing rigs, well service rigs adapted for drilling and/or re-entry operations, and casing drilling rigs, among others within the scope of the present disclosure.
The driven plate 204, visible in phantom in
The elastomeric element 206 may be a cylindrical component configured to absorb and dampen vibration and shock in order to protect components of the drilling rig 100. In this implementation, the elastomeric element 206 includes a main body portion 220 and elastomeric element plates 404 disposed at each end of the main body portion 220.
In some implementations, the main body portion 220 and the elastomeric element plates 404 may be formed of any elastomeric material, including rubber or other polymeric materials. In other implementations, the main body portion 220 is formed of an elastomeric material, and the elastomeric element plates 404 may be formed of a non-elastomeric material. In some implementations, the elastomeric element plates 404 may be formed of a rigid material, such as a metal material, that may be embedded within the elastomeric element 206. It is worth noting that the elastomeric element plates 404 may be rigidly adhered to the main body portion 220 such that torsional loads applied to the elastomeric element plates 404 may be dampened by the main body portion 220.
The elastomeric element plates 404 may include bosses 406 that may facilitate attachment of the main body portion 220 to the drive plate 202 and to the driven plate 204. For example, the bosses 406 may extend from the elastomeric element plates 404 at opposing ends of the main body portion 220. In some embodiments, the bosses 406 may be arranged to receive bolts or other fasteners that connect the elastomeric element 206 to the drive plate 202 and the driven plate 204. As can be seen in the cross-sectional view in
As best seen in
In this implementation, the drive plate 202, the driven plate 204, and the elastomeric element 206 may be connected together to form a subassembly. In implementations where the drive plate 202 and driven plate 204 are disc shaped, the housing 210 may be cylindrical and hollow so that it is adapted to receive and enclose the drive plate 202, the driven plate 204 and the elastomeric element 206. In some embodiments, the housing 210 may be fixedly secured at one end to driven plate 204, for example via welds. In other embodiments, the housing 210 and the driven plate 204 may be formed of a monolithic material. Housing 210 may extend away from driven plate 204 to enclose elastomeric element 206 and drive plate 202 in its hollow center portion 211. Housing 210 may have spaced windows or openings 212 through its outer walls that expose at least some portions of drive plate 202. At least a portion of the sides of windows 212 may serve as positive stops 214 (
In the exemplary embodiment shown, the drive plate 202, the driven plate 204, and the elastomeric element 206, all include a centrally disposed passage 218 that enables fluid such as compressed air to pass from the top drive through the shock absorber 108, and into the drill string.
The removable lugs 216 may be generally triangular or sector shaped and may be formed to fit generally within the pockets 302. However, the removable lugs 216 may have a radial length greater than a radial length of the pockets 302, such that when seated into pockets 302, the removable lugs 216 may extend radially beyond the edge of drive plate 202. Each of the removable lugs 216 may include striking faces 304 that interface with edges of the windows of the housing 210 in a manner described further below. The exposed strike faces 304 form the sides of the radially distal edge of the removable lugs 216. In the implementation shown, the removable lugs 216 also include a radial lip 230 formed at its most-radial end. As can be best seen in
The circular plate body 222 includes a series of openings 226 that, in the exemplary implementation shown, enable the drive plate 202 to connect with and be rotationally secured to the elastomeric element 206. Referring to
The circular plate body 222 further includes a second series of openings 228 that, in the exemplary implementation shown, enable the drive plate 202 to be fastened to the elastomeric element 206 via fasteners 208. As described above, bosses 406 may be arranged to receive bolts or other appropriate fasteners 208. Openings 228 are sized to allow fasteners 208 to pass through the drive plate 202 into openings 226, which receive bosses 406, such that the fasteners 208 can be fastened into bosses 406, securing the drive plate 202 to the elastomeric element 206, as further described below. In the exemplary embodiment, openings 228 are smaller in diameter than openings 226 so that a portion of drive plate 202 is sandwiched between fasteners 208 and bosses 406 when fasteners 208.
Referring again to
Additionally, when an axial lifting force is applied to the coupling interface 203, elastomeric element 206 may stretch in an axial direction and removable lugs 216 may come into contact with the drive side edge of windows 212, thus transferring the lifting force to the housing 210 and limiting the maximum stretching distance of elastomeric element 206. In the implementation shown, there may be an equal number of removable lugs 216 and windows 212 so that one lug fits into each window 212.
In implementations where the housing 210 and the driven plate 204 are fixed together, assembling the shock absorber 108 may be done by inserting the elastomeric element 206 into the housing 210 so that bosses 406 on the bottom elastomeric element plate 404 fit into recesses on driven plate 204. Fasteners 209 may be used to secure the driven plate 204 to the elastomeric element 206. Removable lugs 216 may each be inserted through a window 212 and fit over a boss 406 on the top elastomeric element plate 404. The drive plate 202 may then be inserted into the housing 210 and fit over the removable lugs 216 and the elastomeric element 206. Fasteners 208 may then be used to secure the drive plate 202 to the elastomeric element 206, sandwiching the removable lugs 216 into place within pockets 302 of drive plate 202, and between the drive plate 202 and the elastomeric element 206.
In some embodiments, the removable lugs 216 may be formed of a sacrificial material that is softer than a material used to form positive stops 214 on housing 210. This is advantageous as it focuses wear on the removable lugs 216 while ensuring that housing 210 remains unworn or less worn by contact between positive stops 214 and removable lugs 216. Furthermore, knowledge of the properties of the sacrificial material of the removable lugs 216 and the material of the housing 210 may allow a user of the drilling rig 100 to know the useful life of the removable lugs 216.
Once removable lugs 216 have reached the end of their useful life due to repeated contact with positive stops 214, fasteners 208 may be removed, freeing drive plate 202 from elastomeric element 206. Drive plate 202 may be lifted away from elastomeric element 206, which frees removable lugs 216 to be lifted off of bosses 406 and removed through windows 212 of housing 210. If the elastomeric element 206 has reached the end of its useful life, fasteners 209 may be removed, freeing elastomeric element 206 from driven plate 204, and elastomeric element 206 may be lifted out of housing 210 and replaced with a new elastomeric element 206. The new elastomeric element 206 may be refastened to driven plate 204 with fasteners 209. A new set of removable lugs 216 may be inserted through windows 212 and placed over bosses 406, and drive plate 202 may be replaced in the housing and secured back to the elastomeric element 206. Accordingly, the removable lugs 216 may be replaced without requiring removal of the coupling interface 203 from the power elements of the drilling rig 100. This may greatly increase the efficiency of maintaining the shock absorber 108 over conventional systems.
If at decision block 508, the elastomeric element 206 needs to be replaced, the method may move from decision block 508 to block 516, and fasteners 209 may be loosened such that driven plate 204 is no longer secured to elastomeric element 206. At block 518, elastomeric element 206 may be lifted in an axial direction away from driven plate 204 and out of housing 210. At block 520, a new elastomeric element 206 may be axially inserted into housing 210 and seated against driven plate 204. At block 522, fasteners 209 may be tightened to secure elastomeric element 206 to driven plate 204. The method may then return to block 510. In the case that the removable lugs 216 have not reached the end of their useful life, old removable lugs 216 may be used in block 510 rather than new removable lugs 216.
Although the disclosure describes the replaceable lugs as being disposed on the drive plate and describes the housing on the driven plate, some implementations include the replaceable lugs on the driven plate and include the housing on the drive plate. In some implementations, the replaceable lugs are removed via an opening in the housing in an axial direction instead of a radial direction.
Various embodiments of the present disclosure may include advantages over prior solutions. In conventional rotational shock absorbers, when the lugs on a drive plate have reached the end of their useful life, the entire drive plate must be removed from the shock absorber, which requires removal of the entire housing from the drill string. Additionally, if the lugs are not made out of a sacrificial material, significant wear may occur on the housing itself, requiring replacement of the entire housing and driven plate, which also necessitates removal of the housing from the drill string. By contrast, various embodiments herein allow replacement of worn lugs without removal of the drive plate or the housing from the drill string. Furthermore, use of sacrificial materials for the removable lugs focuses wear on the easily replaceable removable lugs, increasing the life of the housing significantly and reducing uncertainty with respect to what in the shock absorber needs replacement.
As those of some skill in this art will by now appreciate and depending on the particular application at hand, many modifications, substitutions and variations can be made in and to the materials, apparatus, configurations and methods of use of the devices of the present disclosure without departing from the spirit and scope thereof. In light of this, the scope of the present disclosure should not be limited to that of the particular embodiments illustrated and described herein, as they are merely by way of some examples thereof, but rather, should be fully commensurate with that of the claims appended hereafter and their functional equivalents.
This application claims the benefit of the filing date of U.S. Provisional Application 62/301,251, filed Feb. 29, 2016, which is incorporated in its entirety herein by reference.
Number | Name | Date | Kind |
---|---|---|---|
3257827 | Hughes | Jun 1966 | A |
3306078 | Hughes | Feb 1967 | A |
3779040 | Garrett | Dec 1973 | A |
4109488 | Work | Aug 1978 | A |
4575359 | Bermingham | Mar 1986 | A |
5372548 | Wohlfeld | Dec 1994 | A |
5588916 | Moore | Dec 1996 | A |
6332841 | Secord | Dec 2001 | B1 |
Number | Date | Country | |
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20170247946 A1 | Aug 2017 | US |
Number | Date | Country | |
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62301251 | Feb 2016 | US |