STUCK PACKER MILLER AND EXTERNAL RETRIEVAL TOOL

Abstract

A downhole retrieval tool includes: an upper sub-assembly disposed at a proximal end of the retrieval tool; an engagement body disposed axially adjacent to the upper sub-assembly, with respect to a central longitudinal axis of the retrieval tool; and a milling tool disposed at a distal end of the retrieval tool. The engagement body is configured to selectively constrict about a portion of production tubing extending from a packer assembly, the packer assembly comprising a packer element. The milling tool is configured to mill one or more portions at an outer periphery of the packer element. A related method includes deploying and utilizing such a retrieval tool downhole.

Description

BACKGROUND

Hydrocarbon fluids are located below the surface of the Earth in subterranean porous rock hydrocarbon-bearing formations called “reservoirs.” In order to extract the hydrocarbon fluids, wells may be drilled to gain access to the reservoirs.

A step in the drilling operations may include well construction activities, such as casing the wellbore. During casing construction, in some instances casing is cemented in place along a portion of the length of the wellbore. In such an instance, upon completion of drilling a section of well bore, the drill string may be pulled out of the wellbore and a section of casing is deployed and cemented into place to create fluid and mechanical isolation from the newly drilled formation.

Production tubing is then typically installed for the purpose of recovering reservoir fluids. In the process, an annular gap or space between the production tubing and surrounding casing (or other tubular) is bridged via a production packer. In so doing, an annular volume above the packer is effectively sealed off from an annular volume below, to prevent or inhibit migration of fluids or gases (of any type) between the lower and upper annular volumes.

At times, a seal assembly or portion of the production tubing may become stuck in a production packer and render the packer useless. Normally, recovering the packer is a challenging process as several steps are typically undertaken before the packer can even be milled out. Related logistical complexities have eluded ready resolution.

SUMMARY

This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

In one aspect, embodiments disclosed herein relate to a downhole retrieval tool including: an upper sub-assembly disposed at a proximal end of the retrieval tool; an engagement body disposed axially adjacent to the upper sub-assembly, with respect to a central longitudinal axis of the retrieval tool; and a milling tool disposed at a distal end of the retrieval tool. The engagement body is configured to selectively constrict about a portion of production tubing extending from a packer assembly, the packer assembly comprising a packer element. The milling tool is configured to mill one or more portions at an outer periphery of the packer element.

In one aspect, embodiments disclosed herein relate to a method including deploying a downhole retrieval tool into a wellbore. The retrieval tool includes: an upper sub-assembly disposed at a proximal end of the retrieval tool; an engagement body disposed axially adjacent to the upper sub-assembly, with respect to a central longitudinal axis of the retrieval tool; and a milling tool disposed at a distal end of the retrieval tool. The retrieval tool is disposed axially adjacent to a packer assembly and a portion of production tubing extending therefrom. Displacement of the retrieval tool continues in a downhole direction such that the retrieval tool surrounds a progressively greater length of the portion of the production tubing. The engagement body is selectively constricted about the portion of the production tubing. With the milling tool, one or more portions are milled at an outer periphery of a packer element of the packer assembly.

Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.

BRIEF DESCRIPTION OF DRAWINGS

Specific embodiments of the disclosed technology will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency.

FIG. 1 schematically illustrates, in a cross-sectional elevational view, a conventional drilling rig and wellbore by way of general background and in accordance with one or more embodiments.

FIG. 2 schematically illustrates, in elevational view, a production packer assembly in accordance with one or more embodiments.

FIG. 3 schematically illustrates, in elevational view, a retrieval tool in accordance with one or more embodiments.

FIG. 4 schematically illustrates, in elevational view, the retrieval tool of FIG. 3 engaging with the production packer assembly of FIG. 2, in accordance with one or more embodiments.

FIG. 5 shows a flowchart of a method in accordance with one or more embodiments.

DETAILED DESCRIPTION

In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art that the disclosure may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

Throughout the application, ordinal numbers (e.g., first, second, third, etc.) may be used as an adjective for an element (i.e., any noun in the application). The use of ordinal numbers is not to imply or create any particular ordering of the elements nor to limit any element to being only a single element unless expressly disclosed, such as using the terms “before,” “after,” “single,” and other such terminology. Rather, the use of ordinal numbers is to distinguish between the elements. By way of an example, a first element is distinct from a second element, and the first element may encompass more than one element and succeed (or precede) the second element in an ordering of elements.

In accordance with one or more embodiments, there is broadly contemplated herein a tool configured to externally mill and retrieve a production packer when a seal assembly becomes stuck and is difficult to unstick or remove.

FIG. 1 schematically illustrates, in a cross-sectional elevational view, a conventional drilling rig and wellbore by way of general background and in accordance with one or more embodiments. As such, FIG. 1 illustrates a non-restrictive example of a well site 100. The well site 100 is depicted as being on land. In other examples, the well site 100 may be offshore, and drilling may be carried out with or without use of a marine riser. A drilling operation at well site 100 may include drilling a wellbore 102 into a subsurface including various formations 126. For the purpose of drilling a new section of wellbore 102, a drill string 112 is suspended within the wellbore 102. The drill string 112 may include one or more drill pipes connected to form conduit and a bottom hole assembly (BHA) 124 disposed at the distal end of the conduit. The BHA 124 may include a drill bit 128 to cut into the subsurface rock. The BHA 124 may include measurement tools, such as a measurement-while-drilling (MWD) tool or a logging-while-drilling (LWD) tool (not shown), as well as other drilling tools that are not specifically shown but would be understood to a person skilled in the art.

Additionally, by way of general background in accordance with one or more embodiments, the drill string 112 may be suspended in wellbore 102 by a derrick structure 101. A crown block 106 may be mounted at the top of the derrick structure 101. A traveling block 108 may hang down from the crown block 106 by means of a cable or drill line 103. One end of the drill line 103 may be connected to a drawworks 104, which is a reeling device that can be used to adjust the length of the drill line 103 so that the traveling block 108 may move up or down the derrick structure 101. The traveling block 108 may include a hook 109 on which a top drive 110 is supported. The top drive 110 is coupled to the top of the drill string 112 and is operable to rotate the drill string 112. Alternatively, the drill string 112 may be rotated by means of a rotary table (not shown) on the surface 114. Drilling fluid (commonly called mud) may be pumped from a mud system 130 into the drill string 112. The mud may flow into the drill string 112 through appropriate flow paths in the top drive 110 or through a rotary swivel, if a rotary table is used (not shown).

Further, by way of general background in accordance with one or more embodiments, and during a drilling operation at the well site 100, the drill string 112 is rotated relative to the wellbore 102 and weight is applied to the drill bit 128 to enable the drill bit 128 to break rock as the drill string 112 is rotated. In some cases, the drill bit 128 may be rotated independently with a drilling motor. Generally, it is also possible to rotate the drill bit 128 using a combination of a drilling motor and the top drive 110 (or a rotary swivel if a rotary table is used instead of a top drive) to rotate the drill string 112. While cutting rock with the drill bit 128, drilling fluid or “mud” (not shown) is pumped into the drill string 112. The mud flows down the drill string 112 and exits into the bottom of the wellbore 102 through nozzles in the drill bit 128. The mud in the wellbore 102 then flows back up to the surface 114 in an annular space between the drill string 112 and the wellbore 102 carrying entrained cuttings to the surface 114. The mud with the cuttings is returned to the mud system 130 to be circulated back again into the drill string 112. Typically, the cuttings are removed from the mud, and the mud is reconditioned as necessary, before pumping the mud again into the drill string 112.

Moreover, by way of general background in accordance with one or more embodiments, drilling operations are completed upon the retrieval of the drill string 112, the BHA 124, and the drill bit 128 from the wellbore 102. In some embodiments of wellbore 102 construction, production casing operations may commence. A casing string 116, which is made up of one or more larger diameter tubulars that have a larger inner diameter than the drill string 112 but a smaller outer diameter than the wellbore 102, is lowered into the wellbore 102 on the drill string 112. Generally, the casing string 116 is designed to isolate the internal diameter of the wellbore 102 from the adjacent formation 126. Once the casing string 116 is in position, it is set and cement is typically pumped down through the internal space of the casing string 116, out of the bottom of the casing shoe 120, and into the annular space between the wellbore 102 and the outer diameter of the casing string 116. This secures the casing string 116 in place and creates the desired isolation between the wellbore 102 and the formation 126. At this point, drilling of the next section of the wellbore 102 may commence.

The disclosure now turns to working examples of a downhole drilling motor assembly in accordance with one or more embodiments, as described and illustrated with respect to FIGS. 2-5. It should be understood and appreciated that these merely represent illustrative examples, and that a great variety of possible implementations are conceivable within the scope of embodiments as broadly contemplated herein.

FIG. 2 schematically illustrates, in elevational view, a production packer assembly 220 in accordance with one or more embodiments. Particularly, the production packer assembly 220 may represent essentially any conventional packer assembly which may be employed in the context of one or more embodiments. As shown, production packer assembly 220 is disposed about production tubing 218 (e.g., standard tubing 4½ in. in diameter) in a manner to seal off an annulus between tubing 218 and a portion of a casing string (such as the casing string 116 shown in FIG. 1). Indicated at 219 is a suitable coupling element for coupling the production tubing 218 into production packer assembly 220. Production packer assembly 220 includes generally cylindrical main body 221 and a packer element 222 mounted on the main body 221. Packer element 222 includes an inflatable packer 226 axially positioned between upper and lower slips 224 and 228 (respectively). In known manner, the slips 224/228 serve to anchor the assembly 220 within the internal surface of a casing string, and the packer 226 inflates in a manner to expand and bridge the aforementioned annulus.

As shown in FIG. 2, in accordance with one or more embodiments, production tubing 218 may become stuck with respect to packer assembly 220. Conventionally, a cumbersome and costly workover operation is typically then needed to recover the packer assembly 220 and reestablish access to the wellbore. For instance, production tubing 218 may be cut, with washover pipe tools then run in hole. However, the related retrieval process normally requires two or more attempts followed by running in hole with a separate fishing catch tool.

FIG. 3 schematically illustrates, in elevational view, a retrieval tool 330 in accordance with one or more embodiments. In stark contrast to conventional arrangements, retrieval tool 330 is capable of milling out one or more portions of packer element 222 and retrieving packer assembly 220 and at least a portion of production tubing 218 all in one run. As shown, tool 330 includes several components axially aligned with one another (with respect to a central longitudinal axis X), including an upper sub-assembly (or “upper sub”) 332; an engagement body 334; an extension portion 336; and a milling tool 338. Tool 330 may be mounted at the end of a drill string, such as the drill string 112 shown in FIG. 1.

In accordance with one or more embodiments, upper sub includes a cylindrical upper neck portion 340, a frustoconical transition portion 342 and a cylindrical lower body portion 344. Engagement body 334, disposed axially adjacent to the cylindrical lower body portion 344, may be formed with a helically tapered spiral section at its inner surface, with a gripping member fitted therewithin. Such a gripping member may be embodied as a grapple, as generally known in the hydrocarbon recovery arts. Thus, when the gripping member is applied and an uphole pulling force is exerted against a fish, or item to be grasped and retrieved (such as the production tubing portion 218 in FIG. 2), an expansion strain is spread evenly over a long section of the fish. No damage or distortion results to either the fish or the engagement body 334.

In accordance with one or more embodiments, a grapple 335 installed as part of engagement body 334 will be dimensioned such that its inner size, when deployed, will match the outer diameter of production tubing portion 218. A suitable grapple control, as generally known to those of ordinary skill in the art, can be included to permit the grapple to reciprocate in an axial direction while simultaneously transmitting a full torsional force from the grapple 335 to the production tubing portion 218.

In accordance with one or more embodiments, extension portion 336 may essentially be embodied by a cylindrical portion, while milling tool 338 includes a main body portion 346 and milling head 348.

In accordance with one or more embodiments, milling head 348 may be rotatably mounted with respect to main body portion 346 and central longitudinal axis X. Alternatively, main body portion 346 may be embodied as a carrier which is rotatably mounted about axis X, with milling head 348 rigidly mounted thereon. For its part, milling head 348 may be generally annular in shape, to mill one or more portions of an outer periphery of a packer element such as that indicated at 222 in FIG. 2. The milling head 348 may be embodied by a solid body which is contoured for such milling, including a plurality of suitable cutting edges, or may include cutting inserts that are mounted at milling head 348 along a circumference thereof. The cutting edges or cutting inserts may be formed from any suitable material, such as tungsten carbide. As tool 330 may indeed be mounted at the distal end of a drill string, the milling head 348 may be rotationally driven via action of a top drive or rotary table at the proximal end of the drill string, and via resultant rotation of main body portion 346.

In accordance with one or more embodiments, by way of sample dimensions, and merely as illustrative and non-restrictive examples, upper neck portion 340 and frustoconical transition portion 342 may together extend an axial length A of about 2 feet. Lower body portion 344 may have an axial length B of about 1 foot. Upper neck portion 340 may have an outer diameter consistent with or equivalent to that of a drill pipe joint in the drill string at hand. Engagement body 334 may have an axial length C of about 3 feet. Extension portion 336 may have an axial length D of about 20 feet, an inner diameter of about 5 to about 5.2 inches (e.g., about 5.126 inches) and an outer diameter of about 6 inches. Main body portion 346 of milling tool 338 may have an axial length E of about 4 feet; this length may also include the milling head 348. Lower body portion 344, engagement body 334, extension portion 336 and main body portion 346 of milling tool 338 may have the same outer diameter. The milling head 348 may also have this same outer diameter, or a larger outer diameter.

FIG. 4 schematically illustrates, in elevational view, the retrieval tool 330 of FIG. 3 engaging with the production packer assembly 220 of FIG. 2, in accordance with one or more embodiments.

In accordance with one or more embodiments, FIG. 4 illustrates a course of action taken by retrieval tool 330 in the event of a stuck seal assembly (e.g., within production packer assembly 220). For instance, production tubing 218 may be stuck within production packer assembly 220 and cannot be individually pulled away and retrieved therefrom. Thus at least in this instance, it can be assumed that as a remedy for being stuck, production tubing 218 has been cut in preparation for milling and retrieval. As shown, retrieval tool 330 may be run in hole until it is disposed axially adjacent to the production packer assembly 220 with remaining production tubing 218 extending therefrom. Retrieval tool 330 may then continue downhole (axially downwardly with respect to the drawing) until the retrieval tool 330 “swallows” over the tubing 218. In other words, the retrieval tool 330 may be understood as being hollow throughout its overall length, and the retrieval tool 330 thus surrounds a progressively greater length of the tubing 218, without contacting the same, as the tool continues to displace downhole.

In accordance with one or more embodiments, as retrieval tool 330 progresses towards and past the constituent portions of packer element 222, the milling head 348 may then be rotationally driven to mill one or more of the upper slip 224, packer 226 and lower slip 228. Whether at such a juncture or thereafter, grapple 335 of the engagement body 334 can be deployed as shown to expand or extend radially inwardly to constrict or grab onto production tubing 218, and as described heretofore. Subsequently, the retrieval tool 330 may be deployed uphole (in an axially upward direction with respect to the drawing) and thus retrieve the entire production tubing (remnant) 218 along with the packer assembly 220.

FIG. 5 shows a flowchart of a method, as a general overview of steps which may be carried out in accordance with one or more embodiments described or contemplated herein.

As such, in accordance with one or more embodiments, a downhole retrieval tool is deployed into a wellbore (550). The retrieval tool includes: an upper sub-assembly disposed at a proximal end of the retrieval tool; an engagement body disposed axially adjacent to the upper sub-assembly, with respect to a central longitudinal axis of the retrieval tool; and a milling tool disposed at a distal end of the retrieval tool (552). The retrieval tool can correspond to that indicated at 330 in FIGS. 3 and 4, along with its constituent components (332, 334, 338) also described and illustrated herein.

In accordance with one or more embodiments, the retrieval tool is disposed axially adjacent to a packer assembly and a portion of production tubing extending therefrom (554). The packer assembly and portion of production tubing can correspond to those indicated at 220 and 218, respectively, in FIGS. 2 and 4. The retrieval tool continues to be displaced in a downhole direction such that the retrieval tool surrounds a progressively greater length of the portion of the production tubing (556). The engagement body is constricted about the portion of the production tubing (558) and, with the milling tool, one or more portions are milled at an outer periphery of a packer element of the packer assembly (560). The packer element may correspond to that indicated at 222 in FIGS. 2 and 4.

Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. § 112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.

Claims

1. A downhole retrieval tool comprising:

an upper sub-assembly disposed at a proximal end of the retrieval tool;

an engagement body disposed axially adjacent to the upper sub-assembly, with respect to a central longitudinal axis of the retrieval tool; and

a milling tool disposed at a distal end of the retrieval tool;

the engagement body including a grapple that selectively constricts about a portion of production tubing extending from a packer assembly, the packer assembly comprising a packer element,

wherein the grapple has an axial length of about 3 feet, and is installed to reciprocate in an axial direction while simultaneously transmitting a full torsional force to the portion of production tubing; and

the milling tool being configured to mill one or more portions at an outer periphery of the packer element.

2. The downhole retrieval tool according to claim 1, wherein the milling tool comprises:

a main body portion; and

a milling head disposed on the main body portion,

wherein the milling head is generally annular in shape.

3. The downhole retrieval tool according to claim 2, wherein the packer element comprises a production packer element.

4. The downhole retrieval tool according to claim 3, wherein the upper sub-assembly, engagement body, and milling tool are hollow.

5. The downhole retrieval tool according to claim 4, further comprising a hollow extension portion which extends from the engagement body to the milling tool.

6. The downhole retrieval tool according to claim 5, wherein the extension portion is generally cylindrical in shape.

7. The downhole retrieval tool according to claim 6, wherein the upper sub-assembly comprises:

a cylindrical upper neck portion;

a frustoconical transition portion disposed axially adjacent to the upper neck portion; and

a cylindrical lower body portion disposed axially adjacent to the transition portion.

8. The downhole retrieval tool according to claim 7, wherein the upper neck portion has a smaller diameter than the lower body portion; and

wherein the lower body portion is disposed axially adjacent to the extension portion.

9. (canceled)

10. A method comprising:

deploying a downhole retrieval tool into a wellbore, wherein the retrieval tool comprises: an upper sub-assembly disposed at a proximal end of the retrieval tool; an engagement body disposed axially adjacent to the upper sub-assembly, with respect to a central longitudinal axis of the retrieval tool, wherein the engagement body includes a grapple having an axial length of about 3 feet; and a milling tool disposed at a distal end of the retrieval tool;

disposing the retrieval tool axially adjacent to a packer assembly and a portion of production tubing extending therefrom;

continuing to displace the retrieval tool in a downhole direction such that the retrieval tool surrounds a progressively greater length of the portion of the production tubing;

selectively constricting the grapple about the portion of the production tubing, via reciprocating the grapple in an axial direction while simultaneously transmitting a full torsional force to the portion of production tubing; and

with the milling tool, milling one or more portions at an outer periphery of a packer element of the packer assembly.

11. The method according to claim 10, wherein the constricting and milling are performed in a single run of the retrieval tool downhole.

12. The method according to claim 11, further comprising deploying the retrieval tool uphole after the constricting and milling, thereby retrieving the production tubing and packer assembly.

13. The method according to claim 12, wherein the milling tool comprises:

a main body portion; and

a milling head disposed on the main body portion,

wherein the milling head is generally annular in shape.

14. The method according to claim 13, wherein the packer element comprises a production packer element.

15. The method according to claim 14, wherein the upper sub-assembly, engagement body, and milling tool are hollow.

16. The method according to claim 15, wherein the production packer element comprises an upper slip, an inflatable packer disposed axially adjacent to the upper slip, and a lower slip disposed axially adjacent to the inflatable packer.

17. The method according to claim 16, wherein the retrieval tool further comprises a hollow extension portion which extends from the engagement body to the milling tool.

18. The method according to claim 17, wherein the extension portion is generally cylindrical in shape.

19. The method according to claim 18, wherein the upper sub-assembly comprises:

a cylindrical upper neck portion;

a frustoconical transition portion disposed axially adjacent to the upper neck portion; and

a cylindrical lower body portion disposed axially adjacent to the transition portion.

20. The method according to claim 19, wherein the upper neck portion has a smaller diameter than the lower body portion; and

wherein the lower body portion is disposed axially adjacent to the extension portion.