Patent Application
20190106958
NONE
The present invention pertains to a mill or cutting assembly for the downhole cutting of tubular goods in wellbores. More particularly, the present invention pertains to a downhole mill or cutting assembly having radially or outwardly extending cutter bases. More particularly still, the present invention pertains to a locking assembly for securing cutting bases of a downhole mill or cutting assembly in a radially or outwardly extended position during use.
It is often desirable, and sometimes necessary, to conduct downhole operations within a wellbore for any number of different reasons. One common downhole operation involves the plugging and abandonment of depleted wells. After hydrocarbon reserves accessible from a well have been fully recovered, the wellbore must eventually be plugged and abandoned and the well site restored to its original condition.
Typically, as much production tubing and casing as possible is retrieved from a well as part of the plugging and abandonment process. In many cases, such recovered tubular goods can be reused in other wells or sold for salvage. However, because the pipe—and especially the casing—can be cemented or otherwise secured in place within a wellbore, downhole blades or other cutting devices are frequently required to cut the pipe at desired depths in the well prior to removal. In many cases, such cutting equipment is conveyed in and out of a well via tubular workstring. After desired down-hole cut(s) are made, the workstring and the severed pipe are typically pulled out of the well from the surface.
Various tools have been developed for downhole cutting or severing of casing strings in wellbores, and for cutting or milling window sections in casing strings. Generally, such tools have comprised a main body with multiple hinged arms or blades, which are rotated outwardly into contact with the casing (by hydraulic or other means) when the tool is in position downhole. Fluid is typically pumped down through the tubular drillstring and the tool in order to actuate the mechanism and rotate the blades outward. Once the blades are rotated outwardly toward the surrounding casing, rotation of the drillstring (and tool) causes the cutting surfaces on the blades to cut through the casing string. Fluids are pumped through the system to lift cuttings or shaving debris to the surface.
Conventional cutting tools cannot efficiently cut or sever multiple, cemented-together casing strings and, in particular, cannot efficiently cut “windows” in such strings; as used herein, the term “window” means the cutting or milling of a section (e.g., 20′ or more) of the casing string, as opposed to simply severing the casing string. In addition, conventional downhole tools tend to create long, connected metal shavings which must be lifted (or “circulated”) from a wellbore by fluid flow, or else said shavings can become nested together downhole and potentially cause the drillstring to become stuck within a wellbore.
In an effort to overcome such limitations, a downhole cutting assembly has been developed having a plurality of elongated cutter bases hingedly connected to a main body. Said elongated cutter bases are connected to said main body using a plurality of linkage arms, and are movable from a first position substantially recessed into said main body, to a second position extended radially outwardly from the main body. An operating mechanism within the main body, operable by fluid flow, moves the linkage arms and cutter bases between said positions. The linkage arms hold the cutter bases substantially parallel to the axis of the main body; a plurality of cutter blades or “knives” is mounted on the cutter bases, and engages the casing string when the cutter bases are in said (second) outwardly extended position.
Although such cutting devices are effective, problems can arise when the annular gap—that is, the distance between the outside of the body member and the inner surface of the casing to be milled—is relatively small. For example, when the angle of attack of a linkage arm with the casing is less than about 20 degrees, or when the casing is equipped with flush joint connections which prevent such linkage arms from fully extending or expanding radially outward from said body member, said linkage arms can tend to collapse inward after some period of use. Frequently, tapered cutting blades or knives, together with the weight of the assembly and/or an attached workstring, can result in unwanted collapsing of said linkage arms.
Thus, there is a need for means to lock said linkage arms of a downhole cutting assembly in a radially outward or extended position, particularly when tapered cutting blades are utilized, and/or when the annular gap or distance existing between the outside of the body member and the inner surface of the casing to be milled is relatively small.
In a preferred embodiment, the present invention comprises a well bore casing mill or cutting assembly having expandable cutter bases. Said casing mill, embodying the principles of the present invention, comprises a main body having a longitudinal bore therethrough. Means for connecting the main body to a drill string, typically threaded connections, are provided on at least the upper end of said main body.
A plurality of elongated cutter bases are hingedly connected to said main body by a plurality of linkage arms, and are movable from a first position substantially recessed into the main body, to a second position extended outwardly from the main body. An operating mechanism within the main body, operable by fluid flow, moves the linkage arms and cutter bases. The linkage arms hold the cutter bases substantially parallel to the axis of the main body. A plurality of cutters is mounted on the cutter bases, and engages the casing string when the cutter bases are in an outwardly extended (cutting) position.
A piston assembly comprises a piston body having a plurality (typically three) pockets or recesses, each for receiving a lock button. Each lock button is retained in place within a pocket or recess using a spring and spring retainer. Nozzle(s) are beneficially positioned in proximity (typically below) said lock button pockets or recesses. Said piston body is slideably received within a lock ring held said body using at least one shear screw. A piston stop is provided to prevent backward movement of said piston, particularly while tripping in hole with the cutting assembly of the present invention.
In operation, the cutting assembly of the present invention can be tripped or run in a wellbore to a desired depth. After reaching said depth, said cutting assembly can be selectively activated by pumping fluid through said nozzle at a pre-determined flow rate. When a predetermined fluid pressure acting on the piston (which, by way of illustration but not limitation, can typically be in a range between 1000-2200 psi) is achieved, force will act on a drive link cam opening the cutter arms to which the knives are attached.
Said piston further comprises at least one lock button. When said fluid is pumped through said nozzle(s), said at least one lock button will be exposed to the same fluid pressure. Force resulting from said fluid pressure will cause said at least one lock button to move radially outward until it engages against a lock ring sleeve. In a preferred embodiment, said lock ring sleeve has threads or ridges that are designed to hold loading in only one axial direction. As such, said at least one lock button and lock ring cooperate to act as ratchet assembly; said ratchet assembly will provide resistance to prevent said arms from collapsing, while allowing substantially free movement in opposite axial direction. The loads acting on lock ring sleeve are equally distributed between the lock button(s).
During operation within a wellbore, the present invention will ensure that cutter arm do not collapse inward when said cutting assembly is used, even in casings having a relatively small inner diameter or casings with flush connections. Further, when the pumping of fluid ceases, a differential pressure will also cease, thereby allowing said spring(s) to bias said lock button(s) away from the lock ring sleeve. In this manner, said linkage arms can be easily collapsed inward, such as when the cutting assembly is being retrieved or pulled out of a wellbore.
In the event that said piston does not collapse as desired when pumping of fluid ceases, the cutting assembly can be picked up using a tubular workstring. In such a scenario, the axial force applied to said cooperating lock button(s) and lock sleeve is increased until said shear screw(s) holding said lock ring sleeve in place will shear at a predetermined or preset force. After the shear screw(s) shear, said lock ring sleeve can move, thereby disengaging from said lock button(s) and permitting said linkage arms to collapse radially inward toward said body member.
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.
While the present invention will be described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the present invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments (and legal equivalents thereof).
Referring to the drawings,
In a preferred embodiment, said wellbore cutting assembly 10 comprises a ported sub 60 connected to a body member 20. Although not depicted in
Body member 20 has at least one elongate recess 28 defined or formed in exterior surfaces of said body member 20. At least one cutter base 30 is operationally attached to body member 20 using pivotally attached upper linkage or positioning arms 50, and pivotally attached lower linkage or positioning arms 51. In the collapsed configuration depicted in
Wellbore cutting assembly 10 comprises ported sub 60 having a means for connection and operational attachment to a tubular workstring (not visible in
In a preferred embodiment, upper linkage arms 50 and lower linkage arms 51 are of substantially equal length. As such, it is understood that when cutter bases 30 are in an extended position (as depicted in
Wellbore cutting assembly 10 further comprises a means for moving cutter bases 30 from a first, retracted position (generally within body member 20 and not protruding significantly therefrom, as shown in
Body member 20 has at least one elongate recess 28 defined or formed in the exterior of said body member 20. Although not visible in
Still referring to
A plurality of cutters 40 is mounted on an exterior portion of each of said cutter bases 30. While various embodiments of cutters 40 may be used, one suitable embodiment uses a metal base or cutter plate which is attached to cutter base 30 by welding or similar means. In a preferred embodiment, said cutters 40 may be covered with carbide or other suitable hardened surface, or a combination of hardened material buttons and carbide or similar materials. However, it is to be observed that a variety of cutting surfaces are suitable, so long as they present a hardened surface to the surrounding casing to be engaged in order to permit milling of same.
In a preferred embodiment, cutters 40 are preferably arranged in a plurality of vertically spaced apart rows along a desired portion of the length of each cutter base 30. To facilitate milling in a downward direction, with conventional right-hand rotation of a drillstring, cutters 40 may be angled or inclined, wherein an upper end of cutters 40 may be inclined in a direction of rotation of wellbore cutting assembly 10. The number, position, and spacing of cutters 40 may be varied to suit particular applications.
With cutters 40 positioned in a plurality of vertically spaced apart, horizontally aligned rows, it can be appreciated that as milling progresses, and a row of cutters wears out, the diameter of the cutters decreases such that the next row of cutters 40 above moves downward into contact with a surrounding casing surface to be cut or milled. In this manner, a fresh cutting surface is presented to a casing edge being milled. It can be appreciated that the multiple rows of cutters 40 permit cutting assembly 10 to remain in a wellbore for an extended period, thereby greatly reducing time spent in pulling and re-dressing cutting surfaces of said cutting assembly 10.
Although not visible in
Referring to
Body member 20 has elongate recesses 28 formed in the exterior of said body member 20. At least one cutter base 30 is operationally attached to body member 20. Upper linkage arms 50 are pivotally attached to body member 20 using upper pivot pins 52, and to said cutter bases 30 using pivot pins 53. Lower linkage arms 51 are pivotally attached to body member 20 using lower pivot pins 54, and to cutter base 30 using pivot pins 55. A plurality of cutters 40 is mounted on an exterior portion of each of said cutter bases 30.
Body member 20 has an elongate central through bore 26 extending at least partially along the length of said central body member 20. Lock ring sleeve 120 is disposed within said central through bore 26. Similarly, piston member 80 is moveably disposed within said bore 26, while piston stop 84 disposed within said central bore 26 of body member 20 to limit upward travel of said piston member 80. A lock button 110 is moveably disposed within each lock button recess 90 in said piston member 80.
Referring to
Piston 80 is moveably disposed in central through bore 26 of body member 20; as such, central through bore 82 of piston 80 has a smaller diameter than bore 26 of body member 20. Piston body section 82 further comprises at least one (typically three) transverse lock button recess 90, while a Lock button 110 is moveably disposed within each said lock button recess 90. In the configuration depicted in
Lock button 110 has external ridges 111, outer channel 117 and rear extension 116. An elastomeric o-ring 112 is received on said rear extension 116; said rear extension 116 and o-ring 112 are slidably received within transverse mounting port 92. Lock button 110 is retained in place within recess 90 using spring 113 and spring retainer 114 secured to body section 80 using threaded fasteners 115 received in threaded bores 118. Spring 113 pushes against spring retainer 114, and acts to bias lock button 110 radially inward within lock button recess 90.
In a preferred embodiment, lock ring sleeve 120 has inwardly facing ridges 121 that are designed to hold loading in only one axial direction. Specifically, referring to
During operation within a wellbore, the present invention will ensure that cutter bases 30 do not collapse radially inward toward main body 20, particularly when said cutting assembly 10 is used in relatively small casings or casings with flush connections. Further, when the pumping of fluid ceases, a differential pressure acting on lock button(s) 110 will also cease, thereby allowing spring(s) 113 to bias said lock button(s) 110 away from lock ring sleeve 120. In this manner, linkage arms 50 and 51can be easily collapsed inward (resulting in cam shaped heel extensions 56 “pushing” piston member within bore 26), such as when fluid pumping ceases and/or cutting assembly 10 is being retrieved or pulled out of a wellbore.
By way of illustration, but not limitation, and without confining the current invention to any particular configuration or operating mechanism, it is to be observed that U.S. Patent Applicant Publication No. 2017/0298705 discloses an embodiment of cutting assembly that can be utilized with the locking assembly of the present invention. The disclosure of said patent application is incorporated herein by reference to the extent necessary to illustrate an exemplary tool configuration and/or operating mechanism thereof. Nonetheless, it is also to be observed that the locking mechanism of the present invention can also be beneficially employed with other cutting tools or devices.
In a preferred embodiment, said central through bore 26 extends sufficiently far along the length of body member 20 to route fluid to the positioning arm area, but bore 26 typically should not run the entire length of body member 20. By having only a partial length bore, and forcing fluid to exit the tool through transverse flow ports in the vicinity of positioning arms 50 and the recess(es) 28 in body member 20 into which cutter bases 30 retract, fluid flow tends to keep these surfaces flushed and relatively free of cuttings and debris.
While the preceding description contains many specificities, it is to be understood that same are presented only to describe some of the presently preferred embodiments of the invention, and not by way of limitation. Changes can be made to various aspects of the invention, without departing from the scope thereof. For example, dimensions of the various components of the tool can be varied to suit particular jobs; the number of cutter bases can be varied; the number and positioning of cutters per cutter base can be varied; size and shape of the cutters can vary; the angle of the cutters on the cutter bases (that is, the angle with respect to the longitudinal axis of the tool) can be adjusted; the number, size, and placement of the tungsten carbide (or other suitable material) buttons on the cutters can be varied; the configuration of the face surfaces (both as to their multi-sided shape, and the depressions in the face) of tungsten carbide buttons can be varied to provide the most efficient “chip breaker” shape for the application; and methods of use can be varied.
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.
THIS APPLICATION IS A CONTINUATION-IN-PART OF U.S. NON-PROVISIONAL PATENT APPLICATION SER. NO. 15/637,435 FILED JUN. 29, 2017, CURRENTLY PENDING, WHICH IS A CONTINUATION OF U.S. NON-PROVISIONAL PATENT APPLICATION SER. NO. 14/420,612 FILED FEB. 9, 2015, (SUBSEQUENTLY ISSUED AS U.S. PAT. NO. 9,695,660), WHICH IS A UNITED STATES NATIONAL STAGE APPLICATION FROM PCT/US2013/053770, FILED AUG. 6, 2013, THAT CLAIMS PRIORITY OF U.S. PROVISIONAL PATENT APPLICATION SER. NO. 61/681,670, FILED AUG. 10, 2012, ALL INCORPORATED BY REFERENCE HEREIN.
| Number | Date | Country | |
|---|---|---|---|
| 61681670 | Aug 2012 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14420612 | Feb 2015 | US |
| Child | 15637435 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15637435 | Jun 2017 | US |
| Child | 16204459 | US |
