Patent Application
20140262216
None
1. Field of the Invention
The present invention pertains to downhole assemblies having friction reducing elements. More particularly, the present invention pertains to dowhole assemblies having at least one friction reducing element on at least one exterior surface to reduce frictional forces acting on said assemblies. More particularly still, the present invention pertains to downhole assemblies having at least one ball transfer unit on at least one exterior surface.
2. Brief Description of the Prior Art
During operations in the oil and gas industry, a pipe or substantially tubular tool having a certain outer diameter is frequently inserted or otherwise received within a wellbore or pipe having a larger inner diameter. Such operations are often performed during both drilling and production phases of a well's life cycle. By way of illustration, but not limitation, drill pipe, casing and other tubular goods are routinely run into cased and uncased wellbores. Similarly, tools and other downhole assemblies are often conveyed in and out of wells via jointed pipe, continuous (spooled) tubing and/or wireline.
In such cases, frictional forces—typically so-called “sliding friction—from surrounding surfaces acting on such inner pipe or tool(s) can impede such inner pipe or tool(s) from advancing further into a well. In order to reduce or lessen such frictional forces, friction reducing assemblies can be utilized. In most cases, such friction reducing assemblies are installed on at least one outer surface of a tubular or assembly that is being conveyed into a well.
Various types of friction-reducing devices including, without limitation, so-called “roller subs,” are currently used throughout the oil and gas industry in an effort to reduce or limit such sliding friction. Conventional roller subs typically comprise substantially cylindrical body members having radial slots at predetermined intervals. Rollers and/or wheels are rotatably disposed within said slots. In many cases, such roller subs are modular in construction; as such, the roller subs can be assembled in a manner to secure the rollers and/or roller wheels in place, avoiding the need for grub screws and facilitating relatively compact dimensions.
Although such devices can be used in many different applications, use of roller subs is especially prevalent during downhole wireline operations. Such wireline operations generally rely on gravity alone in order to advance a toolstring in a well. As such, roller subs can be especially useful in directional wellbores that deviate substantially from vertical. Roller subs help to reduce sliding friction, thereby allowing wireline tools to advance deeper within a well.
During drilling of a well, stabilizers may be coupled into a drill string to bear against a wall of a drilled hole and thus centralize a drill string in a wellbore. After a well has been drilled, devices known as centralizers may also be employed to centrally locate a liner or casing within a well and provide “stand off” from a surrounding wellbore or casing. Conventional roller subs are also used to reduce sliding friction associated with devices such as stabilizers and centralizers. However, such conventional roller subs are typically not adjustable to various conditions within a well such as, for example, wells having multiple internal diameters.
One type of conventional stabilizer rolling sub assembly comprises rollers mounted on multiple axes, which are each parallel to a longitudinal axis of a stabilizer body (and, hence, also parallel to the longitudinal axis of a drillstring and of a well drilled thereby). The functional effect associated with this form of stabilizer is to reduce rotational friction, while having a neutral or even adverse effect on longitudinal sliding frictional forces.
Conventional roller subs are also sometimes run in connection with bow spring centralizers to reduce sliding friction. However, such bow spring centralizers are typically not sturdy enough to support the full weight of tubing, casing or other pipe strings. Additionally, such conventional centralizer roller subs typically include axles, grub screws and/or other mechanical components that are especially vulnerable to failure during use.
Thus, there is a need for a friction reducing apparatus that significantly reduces frictional forces acting upon tubulars, tool strings, centralizers and/or other downhole assemblies. Such friction reducing apparatus must reduce or diminish frictional forces including, without limitation, sliding friction, generated between outer surface(s) of a pipe or tool, and inner surfaces of a surrounding wellbore or tubular. Among other benefits, the friction reducing apparatus should beneficially assist pipe or downhole tools to traverse obstructions or so-called “tight spots” within a wellbore, minimize or eliminate damage caused when said pipes or downhole tools scrape against surrounding wellbore walls, and reduce rotational friction forces and pipe torsional strain.
In a preferred embodiment, the present invention comprises a substantially cylindrical body member having an outer surface and a plurality of friction reducing elements disposed at least partially along said outer surface. Although many different friction reducing elements can be utilized, said elements can beneficially comprise ball transfer units or other omni-directional rolling-element bearing assemblies.
Although the present invention can take many different configurations, in a preferred embodiment the present invention can comprise a rolling sub assembly, a mule shoe assembly or a centralizer assembly. The friction reducing assembly of the present invention comprises a body section having an outer surface with at least one pocket or recess. At least one ball transfer unit or other omni-directional rolling-element bearing is singly mounted in said at least one pocket or recess, and extends at least partially beyond said outer surface of body section.
The rolling sub, mule shoe and centralizer assemblies of the present invention can be used in many different applications and industries. By way of illustration, but not limitation, the assemblies of the present invention can be used in subterranean well drilling and related operations (water, oil and/or gas wells), mining, deviated holes for construction purposes, quarry drilling, and pipe cleaning. Further, the friction reducing assemblies of the present invention, having much smaller dimensions, can also be used in various medical applications.
When utilized in oil and/or gas wells, the friction reducing assemblies of the present invention provide a number of significant operational benefits. Specifically, the friction reducing assemblies of the present invention allow pipe deployment in highly-deviated and/or horizontal wellbores. Said friction reducing assemblies substantially reduce rotational friction and torque in horizontal and diagonal planes, while reducing sliding friction and drag in vertical and diagonal planes. Further, although conventional roller subs typically only permit rotation about a longitudinal axis, the friction reducing assemblies of the present invention permit full 360-degree rotational contact between friction reducing elements and surrounding well or other surfaces.
Additionally, the friction reducing assemblies of the present invention reduce pipe wear and fatigue during deployment (and retrieval, if necessary), while also reducing or eliminating damage to liner tops and liners. Said assemblies permit deployment of tools conveyed via wireline and/or continuous tubing in highly deviated and horizontal wells, while reducing the risk of damage to exposed packer slips and seals.
The foregoing summary, as well as any detailed description of the preferred embodiments, is better understood when read in conjunction with the drawings and figures contained herein. For the purpose of illustrating the invention, the drawings and figures show certain preferred embodiments. It is understood, however, that the invention is not limited to the specific methods and devices disclosed in such drawings or figures.
The present invention comprises an adjustable tension centralizer assembly 100 having a plurality of omni-directional rolling-element bearings that assist the delivery of a centralized tool, pipe section, tubular good, tool, or other device. More particularly, adjustable tension centralizer assembly 100 comprises an adjustable device having friction reducing rolling elements disposed in radially extendable arms. Said friction reducing elements contact and reduce frictional forces against the inner surface of a surrounding casing, hole, pipe or other surrounding enclosure. The adjustable centralizer assembly 100 of the present invention can be included within a larger pipe assembly using threaded connections, set screws, or other connection means well known to those having skill in the art.
Referring to the drawings,
Substantially cylindrical body member 20 is disposed between said first end connection member 10 and second end connection member 12. Said substantially cylindrical body member 20 has outer surface 21 and central through bore 23. A plurality of elongate grooves 22 are disposed at desired spacing around the circumference of said outer surface 21; said elongate grooves 22 are oriented substantially parallel to the longitudinal axis of said body member 20. In a preferred embodiment, substantially cylindrical body member 20 is freely rotatable within said aligned bores 11 and 13 of end connection members 10 and 12, respectively.
First centralizer end collar 30 and second centralizer end collar 31 are disposed around said cylindrical body member 20 and spaced a desired distance apart from each other. A plurality of generally u-shaped centralizer arm members 32 are disposed between said first and second centralizer end collars and pivotally mounted to said first and second end collars. Said centralizer arm members 32 are pivotal about a pivot axis that is oriented substantially parallel to the longitudinal axis of said body member 20. As such, said centralizer arm members 32 are capable of pivoting radially outward from outer surface 21 of body member 20.
Still referring to
Adjustable collar member 50 is slidably disposed on outer surface 21 of central body member 20 and, thus, is capable of moving axially along said central body member 20. Although not depicted in
Wedge assembly 60 comprises base ring 63 as well as a plurality of track arms 61. Base ring 63 is slidably disposed over outer surface 21 of central body member 20, while track arms 61 are slidably received within longitudinal grooves 22 along said outer surface 21 of body member 20. Spring 71 can be disposed between base ring 63 and collar member 50. Wedge latch member 70 having collet fingers 73 can extend under collar member 50 and connect to wedge assembly 60.
Tapered wedge members 62 are disposed on the outer surfaces of track arms 61; in a preferred embodiment, said wedge members 62 have a smaller thickness in the direction of first end connector 10, and a larger thickness in the direction of second end connector 12. Further, said tapered wedge members 62 are at least partially disposed under pivotally mounted centralizer arm members 32 (that is, between outer surface 21 of central body member 20 and said centralizer arm members 32).
Substantially cylindrical body member 20 having outer surface 21 and central through bore 23 is rotatably disposed between said first end connection member 10 and second end connection member 12. A plurality of elongate grooves 22, oriented substantially parallel to the longitudinal axis of said body member 20, are disposed at desired radial spacing around the circumference of said outer surface 21. Opposing first centralizer end collar 30 and second centralizer end collar 31 are disposed around said cylindrical body member 20 and spaced a desired distance apart from each other.
A plurality of generally u-shaped centralizer arm members 32 are disposed between said first and second centralizer end collars 30 and 31, and are pivotally mounted at both ends to said first and second end collars. At least one friction reducing omni-directional rolling element 40 is disposed on an outer surface of each such centralizer arm member 32. Bias springs 33 bias said centralizer arm members 32 in a closed or radially inward direction.
Adjustable collar member 50 is slidably disposed on outer surface 21 of central body member 20. Wedge assembly 60 comprises base ring 63 as well as a plurality of track arms 61. Base ring 63 is slidably disposed over outer surface 21 of central body member 20, while track arms 61 are slidably received within longitudinal grooves 22 along said outer surface 21 of body member 20. Tapered wedge members 62 are disposed on the outer surfaces of track arms 61 and are at least partially disposed between outer surface 21 of central body member 20 and said centralizer arm members 32.
A plurality of elongate grooves 22 are disposed at desired spacing around the circumference of said outer surface 21; said elongate grooves 22 are oriented substantially parallel to the longitudinal axis of said body member 20. In a preferred embodiment, substantially cylindrical body member 20 is freely rotatable within said aligned bores 11 and 13 of end connection members 10 and 12, respectively. First centralizer end collar 30 and second centralizer end collar 31 are disposed around said cylindrical body member 20. A plurality of generally u-shaped centralizer arm members 32 are disposed between said first and second centralizer end collars and pivotally mounted to said first and second end collars.
At least one friction reducing omni-directional rolling element 40 is disposed on an outer surface of each such centralizer arm member 32. In a preferred embodiment, said friction reducing omni-directional rolling elements 40 comprise ball transfer units. Adjustable collar member 50 is slidably disposed on outer surface 21 of central body member 20 and, thus, is capable of moving axially along said central body member 20.
Wedge assembly 60 comprises base ring 63 as well as a plurality of track arms 61. Base ring 63 is slidably disposed over outer surface 21 of central body member 20, while track arms 61 are slidably received within longitudinal grooves 22 along said outer surface 21 of body member 20. Spring 71 is disposed between base ring 63 and collar member 50. Wedge latch member 70 having collet fingers 73 can connect to wedge assembly 60.
Tapered wedge members 62 are disposed on the outer surfaces of track arms 61; in a preferred embodiment, said wedge members 62 have a smaller thickness in the direction of first end connector 10, and a larger thickness in the direction of second end connector 12. Further, said tapered wedge members 62 are at least partially disposed under pivotally mounted centralizer arm members 32 (that is, between outer surface 21 of central body member 20 and said centralizer arm members 32).
Track arms 61 are slidably received within longitudinal grooves disposed along the outer surface 21 body member 20. Tapered wedge members 62 are disposed on the outer surfaces of track arms 61 and are at least partially disposed under pivotally mounted centralizer arm members 32 (that is, between outer surface 21 of central body member 20 and said centralizer arm members 32). At least one friction reducing omni-directional rolling element 40 is disposed on an outer surface of each such centralizer arm member 32. When centralizer arm members 32 are extended radially outward, said rolling elements 40 contact inner wall 201 of pipe section 200.
In operation, adjustable tension centralizer assembly 100 of the present invention can be installed at various locations along toolstrings, workstrings or other downhole assemblies. By significantly reducing sliding and rotational frictional forces, said adjustable tension centralizer assembly 100 allows such toolstrings, workstrings and/or other downhole assemblies to maneuver in and out of wells. By way of illustration, but not limitation, adjustable tension centralizer assembly 100 can be used to deploy packers, bridge plugs and other tools in horizontal or highly deviated wells, eliminating the need for pumping such equipment down such wells. Said adjustable tension centralizer assembly 100 greatly reduces the need to convey equipment in and out of wells using more expensive work strings and continuous tubing, thereby reducing rig down-time and operating costs.
Although adjustable tension centralizer assembly 100 can be included as part of a threaded string of tools or pipe, it is to be observed that said adjustable tension centralizer assembly will typically be received over the outer surface of a tool, tubular, pipe or similar device. When so configured, first end connection member 10 and second end connection member 12 are both secured to the outer surface of said tool, tubular or pipe section using set screws 15 or other fastening means; in this configuration, said tool, tubular or pipe section extends through central through bore 23 of body member 20, which is freely rotatable within said aligned bores 11 and 13 of end connection members 10 and 12.
As noted above, a plurality of generally u-shaped centralizer arm members 32 are disposed between said first and second centralizer end collars and pivotally mounted to said first and second end collars. Said centralizer arm members 32 are each pivotal about a pivot axis that is oriented substantially parallel to the longitudinal axis of said body member 20. As such, said centralizer arm members 32 are capable of pivoting radially outward from outer surface 21 of body member 20.
At least one friction reducing omni-directional rolling element 40 is disposed on an outer surface of each such centralizer arm member 32. In a preferred embodiment, said friction reducing omni-directional rolling elements 40 comprise ball transfer units. Adjustable collar member 50 is capable of moving axially along said central body member 20. As said adjustable collar member 50 move axially toward the mid-point of central body member 20, track arms 61 of wedge assembly 60 move within longitudinal grooves 22 along said outer surface 21 of body member 20.
As said track arms 61 move axially relative to central body member 20, tapered wedge members 62 also move axially under pivotally mounted centralizer arm members 32 (that is, between outer surface 21 of central body member 20 and said centralizer arm members 32). Said wedge members 62 force centralizer arm members 32 radially outward. In this manner, the outer diameter of said radially extending centralizer arm members 32 can be adjusted to a predetermined outer diameter by moving adjustable collar member 50. Once said centralizer arm members 32 are set to a desired location, adjustable collar member 50 can be secured in place.
The outer diameter formed by said cooperating radially extending centralizer arm members 32 can be quickly and easily adjusted, such as when a tool string employing said adjustable tension centralizer assembly 100 is used in multiple wells or pipe sizes having different inner diameters. Further, bias springs 33 permit limited inward movement of said centralizer arm members 32, such as when centralizer assembly 100 must pass through a downhole restriction or so-called “tight spot.”
Sub assembly 300 of the present invention can be placed anywhere (typically by threaded connection) in a longer string of tubing/pipe/coiled tubing, and can be placed as frequently as needed along such length; rolling sub assembly 300 of the present invention can be included within a larger pipe assembly using threaded connections, set screws, or other connection means well known to those having skill in the art.
Roller sub assembly 300 ensures integrity of tubing and casing during their deployment. Mostly used in high deviated wells, the roller sub assembly reduces friction and torque. It incorporates a ball transfer system allowing full rotation and movement in all vertical, horizontal, and diagonal directions. Said roller sub assembly design allows full integrity without compromising pressure loss or the need to have external centralizers which can break or create fishing problems.
Uses for rolling sub assembly 300 of the present invention include, but are not limited to, reducing friction caused by a string scraping on the hole walls, assisting a string to traverse obstructions, minimizing internal scraping of walls, minimizing damage caused by a tool scraping on walls, and to allow a tool string freedom to rotate easier on the trip reducing pipe torsional strain. Rolling elements 304 can have varied configurations or placement on sub 300 including more concentration, varied concentrations, and configurations.
Muleshoe assembly 400 is typically placed on the distal end of a string of pipe, tubing, or other continuous conveyance means. The rolling mule shoe assembly of the present invention has a plurality of rolling 402 elements disposed along the outer surface of body member 401 of said mule shoe assembly 400 in order to reduce sliding friction and to allow the mule shoe assembly to maneuver obstructions, such as commonly found in cylindrical pipe, casing, or uncased wells.
Uses for the rolling mule shoe assembly 400 of the present invention include, but are not limited to, reducing friction caused by string scraping on the hole walls, assisting the string to traverse obstructions, minimizing internal scraping of walls, minimizing damaged caused by a tool scraping on walls, and to allow the tool string freedom to rotate easier on the trip reducing pipe torsional strain. Rolling elements 404 can have varied configurations on muleshoe body 401 including more concentrations, varied orientations, and configurations. Rolling mule shoe assembly 400 of the present invention can be included within a larger pipe assembly using threaded connections, set screws, or other connection means well known to those having skill in the art.
In a preferred embodiment depicted in
The above-described invention has a number of particular features that should preferably be employed in combination, although each is useful separately without departure from the scope of the invention. While the preferred embodiment of the present invention is shown and described herein, it will be understood that the invention may be embodied otherwise than herein specifically illustrated or described, and that certain changes in form and arrangement of parts and the specific manner of practicing the invention may be made within the underlying idea or principles of the invention.
Priority of U.S. Provisional Patent application Ser. No. 61/781,167, filed Mar. 14, 2013, incorporated herein by reference, is hereby claimed.
| Number | Date | Country | |
|---|---|---|---|
| 61781167 | Mar 2013 | US |
