Patent Application
20220381101
The apparatus embodying the principles of the present invention is used in connection with the cutting and/or milling of tubulars downhole, typically those in oil and gas wells (“wells”). In particular, the apparatus may be used to mill a section of a tubular, such as a casing string, where the casing string has a downwardly-facing end at some depth in the wellbore.
As is known in the art, very significant operational and cost savings may frequently be made when operations can be carried out with a workstring comprising coiled tubing, as opposed to a workstring comprising jointed tubulars. However, prior art casing cutting and/or milling tools exhibit various limitations when deployed on coiled tubing.
Apparatus embodying the principles of the present invention, and related methods of use of same, comprise an elongated main body comprising a means for attaching the apparatus to other downhole components, and ultimately to a workstring for lowering it into a wellbore, particularly (although not exclusively) wherein the workstring is a coiled tubing string. A piston, usually with a bore therethrough, is slidably disposed in a longitudinal bore within the main body. A spring, which may be a coil spring or other suitable spring means, biases the piston in an uphole direction. Fluid flow through the bore of the tubular workstring, and the bore of the main body, bears on the piston, with some of the fluid flowing through the piston bore. Sufficient fluid flow bearing on the face of the piston, and through the piston bore, can overcome the uphole force generated by the spring, and force the piston downward (in a downhole direction). An interchangeable jet may be positioned in the bore of the piston to control fluid flow therethrough.
The piston is connected to one or more operating arms, by a pin-type connection (or alternatively a gear type arrangement), such that the operating arms must move when the piston moves, either upward or downward. The operating arms are in turn rotatably connected to the main body, so that when the piston moves downhole, the operating arms are forced to rotate outwardly (extend outwardly). The operating arms are connected to a plurality of elongated cutter bases, and rotation of the operating arms outwardly in turn moves the plurality of cutter bases radially outward. Preferably, the cutter bases are connected to the main body by at least one more set of rotating link members, of substantially equal length to the operating arms, thereby maintaining the cutter bases in a position substantially parallel to the main body.
A plurality of cutters are attached to the cutter bases, by means known in the art. The cutters comprise a hardened cutting surface which is adapted to the milling and/or cutting of the tubular in the wellbore. Preferably, a section of the cutter bases on the upper or uphole end of the cutter bases have no cutters mounted thereon; this creates a stabilizer section especially desirable for milling casing in an uphole direction.
The lowermost or downhole ends of the cutter bases may comprise angled ends which facilitate entry of the tool into tubulars, milling/cutting/cleanout of tubulars, etc. The lower end of the main body may be pointed to ease entry into tubulars, partially obstructed bores, etc.
It can be readily understood that by the pin-type positive connection (or the gear arrangement connection) between the operating piston and the operating arms, that movement of the operating piston whether uphole or downhole always results in corresponding rotation of the operating arms either outwardly or inwardly (uphole movement of the piston resulting in inward rotation/movement of the operating arms; downhole movement of the piston resulting in outward rotation/movement of the operating arms). Further, it can be readily understood that when the piston is moved in an uphole direction by the spring, which happens when fluid flow ceases, that the operating arms, and consequently the cutter bases and cutters, retract to a closed position. In this closed position, the outer diameter of the apparatus is less than the inner diameter of the tubular strings through which it is run, so that the apparatus can be freely moved therethrough and retrieved.
Reference is made to pending U.S. application Ser. No. 14/420,612, owned by the applicant of this application, the disclosure of which is incorporated herein to the extent necessary to provide further background on the structure of the instant invention.
In another embodiment, the piston comprises a locking mechanism which locks the piston in its lowermost or downhole position, where the operating arms and cutter bases are extended, so that downward force on the operating arms and/or cutters/cutter bases (and/or force from the spring) cannot cause retraction of the cutter bases. This keeps the apparatus in its full operating position. In one embodiment, the piston locking mechanism comprises a modified piston assembly. The piston comprises an enlarged chamber at its upper end, wherein a piston releasing sleeve is releasably fixed by means of a shear pin or similar means. The piston releasing sleeve has a ball seat and a bore therethrough. A jet is preferably positioned in the bore of the piston below the chamber, to control fluid flow through the bore. One or more dogs are rotatably fixed to the piston, each of which has an upper and a lower end, such that one end (namely, an upper end) can rotate outwardly (typically under a spring bias), beyond the outer diameter of the piston, while the other end of the dogs extend into the piston chamber. When the piston is moved (by fluid flow) to its lowermost position, the dogs toggle outwardly and the upper ends engage a recess in the bore of the main body, locking the piston in that position.
To retrieve the apparatus, it is necessary to release the piston, and thereby allow the piston to move upward, and the operating arms/cutter bases to move to their retracted position. A suitably sized ball is released down the workstring bore, which seats on the ball seat and seals thereon. Continued pressure shears the shear pin holding the piston releasing sleeve in place, forcing it down into the piston chamber. The piston releasing sleeve forces the lower ends of the dogs radially outward, rotating the upper locking ends out of engagement with the recesses in the main body bore. The piston can then move upwardly in response to the spring bias, and the operating arms/cutter bases move to their retracted position. The tool can then be pulled up through the bore of the workstring and retrieved.
While various apparatus can embody the principles of the present invention, with reference to the drawings some of the presently preferred embodiments can be described.
As can be seen in
A plurality of cutter bases 30 are hingedly attached to main body 20 by a plurality of link arms 32, the uppermost of which comprises a plurality of operating arms 34 as will be later described. As readily understood from the drawings, link arms 32 and operating arms 34 are preferably of substantially equal length, so that cutter bases 30 are substantially parallel to main body 20, as cutter bases 30 move from a first, substantially retracted position as in
A piston 40 is disposed in bore 22 of main body 20. Piston 40 is slidably disposed, and is biased in an uphole or upward direction by spring 50. Piston 40 is connected to operating arms 34 by a pinned connection, as seen in
Piston 40 has a central longitudinal bore 41. An interchangeable jet 48 may be provided to control fluid flow through bore 41. A seal 42 may be provided between piston 40 and bore 22. Fluid pumped down the coiled tubing string, and through bore 22 of main body 20, and the bore of piston 40, at a sufficient rate, will overcome the force exerted by spring 50 and force piston 40 downhole. As described, this will in turn rotate operating arms 34 outwardly, causing cutter bases 30 to move radially outward. When fluid flow ceases, spring 50 moves piston 40 uphole, and cutter bases 30 are moved to their first position as in
A plurality of cutters 60 are mounted on cutter bases 30, spaced in a desired pattern. Preferably, cutters 60 are covered with a hardened cutting material to enable efficient cutting/milling of tubulars. Preferably, a section on cutter bases 30, denoted as stabilizer section “SS” in the figures, generally at an upper or uphole end of the cutter bases, has no cutters mounted thereon, providing a stabilizer section as will be later described.
An exemplary use of the apparatus can now be described, with reference to the drawings. Although use is described in connection with coiled tubing as the workstring, it is understood that jointed tubulars can also be used as the workstring.
Referring to
In
As can be readily understood from the foregoing description, when the apparatus is cutting in an upward direction (namely, being pulled upward by the coiled tubing, and thus pulled upward into the lowermost end of the cut casing string), the forces on the cutter bases/cutters tend to push them downward, thus tending to rotate the operating and link arms toward their retracted position, and to force the piston upward, thereby collapsing the apparatus. The force exerted on the piston by the fluid flow is what resists this movement.
In another embodiment shown in
Referring to
To retrieve apparatus 10, it is necessary to release piston 40, allow the piston 40 to move upward in response to spring 50 (and/or force applied to cutter bases 30/cutters 60 by pulling upward into the casing), and operating arms 34/cutter bases 30 to move to their retracted position. To do so, a suitably sized ball 300 is released down the workstring bore, ball 300 ultimately seating on ball seat 46 and sealing thereon. Continued pressure shears shear pin 200 holding piston releasing sleeve 45 in place, forcing it downwardly in piston chamber 44. This movement of piston releasing sleeve 45 forces the lower ends 103 of dogs 100 radially outward, rotating locking ends 101 out of engagement with recess 26 in main body bore 22. Piston 40 then moves upwardly in response to the bias from spring 50, and the operating arms/cutter bases move to their retracted position. The tool can then be pulled up through the bore of the workstring and retrieved.
In the event that the apparatus cannot be retrieved through the bore of the workstring (e.g. in the event that the operating arms/cutter bases are lodged in an open position), the scope of the invention further comprises a release mechanism, which may be employed in this instance to release the apparatus from the workstring. While different mechanisms may serve this purpose and are included within the scope of the invention, a hydraulic release or disconnect, various types of which are known in the relevant art, may be added to the assembly.
Materials suitable for the present invention are those well known in the relevant field, including high strength metals and alloys thereof, and resilient elements for seals and the like. Fabrication and assembly of the apparatus may be by processes well known in the relevant art.
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.
Therefore, the scope of the invention is to be determined not by the illustrative examples set forth above, but by the appended claims and their legal equivalents.
This non-provisional patent application is a continuation application of and claims priority to pending U.S. patent application Ser. No. 17/220,257, filed Apr. 1, 2021; which was a continuation application of and claimed priority to U.S. patent application Ser. No. 15/758,985, filed Mar. 9, 2018, now USP 10989005; which was a United States national phase entry application from PCT/US2016/051780, filed Sep. 14, 2016; and claims priority to U.S. provisional patent application Ser. No. 62/218,953, filed Sep. 15, 2015, for all purposes. The disclosure of that provisional patent application is incorporated herein, to the extent not inconsistent with this application.
| Number | Date | Country | |
|---|---|---|---|
| 62218953 | Sep 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17220257 | Apr 2021 | US |
| Child | 17883112 | US | |
| Parent | 15758985 | Mar 2018 | US |
| Child | 17220257 | US |
