Method and apparatus for cutting and removing pipe from a well

Abstract

A lifting apparatus for supporting tubular goods that can be used to perform down-hole operations in oil and gas wells. The lifting apparatus has push and pull capability, a minimal footprint, and requires minimal surface area to operate. The support apparatus can be used to jack and remove casing and other pipe, such as during plugging and abandonment operations, and to perform other rig-less downhole well operations.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a system for use with wells drilled into the earth's crust. More particularly, the present invention relates to a rig-less system for conducting plugging and abandonment operations on wells including, without limitation, cutting and retrieving tubular goods from a well.

2. Description of the Prior Art

Oil and gas wells are typically drilled using drilling rigs or other similar systems to create substantially cylindrical boreholes that extend downward into the earth's crust. After a well has been drilled to a desired depth, large diameter pipe commonly referred to as casing is frequently installed into a well and cemented in place. Thereafter, production tubing, packers and/or other equipment is often installed in the well, concentrically inside the casing, in order to provide a conduit for oil and/or gas production to flow from an underground reservoir to the earth's surface.

One common operation conducted on wells is the plugging and abandonment of such wells when they become depleted. After hydrocarbon reserves in a well have been fully recovered, the well must be plugged and abandoned and the well site restored to its original condition. Generally, surface equipment must first be removed from such a depleted well. Thereafter, as much production tubing and casing as possible is typically retrieved from said well; in many cases, such recovered tubular goods can be reused in other wells or possibly even sold for salvage.

Because the pipe—and especially the casing—can be cemented or otherwise secured in place, blades and/or other cutting devices are frequently used to cut the pipe at one or more downhole locations in the well in order to facilitate such removal. After desired down-hole cut(s) are made, the severed pipe is typically pulled out of the well from the surface. However, due to the weight of the pipe, as well as frictional forces acting on such pipe, it is often difficult to pull the casing out of the well. Accordingly, pulling equipment, such as hoists, jacks or the like, are often required to pull the casing out of a well.

In many cases, a single well can have multiple strings of casing. In such cases, a first “outer” casing string having a relatively large diameter is driven into the earth's crust. Thereafter, a second, smaller casing string is concentrically installed within said first casing string (and any bore hole existing below) and cemented in place. This process can be repeated until a desired length of casing is installed in the well. Wells having multiple strings of casing and/or other pipe can further complicate plugging and abandonment operations.

Drilling rigs and smaller work-over rigs can be used to plug and abandon wells. A rig's rotary equipment can be utilized to actuate blades and/or other cutting equipment conveyed on a tubular workstring in order to make down-hole cuts in a well. Further, a rig's derrick and draw works can also be used to pull severed casing or other pipe from a well. However, the use of conventional rigs to perform plugging and abandonment operations can be expensive. When conventional rigs are used, such rigs and related equipment must be mobilized to a location prior to commencing work, and demobilized after such work is completed.

In order to eliminate some of the expense associated with using conventional rigs for plugging and abandonment operations, certain rig-less systems have been devised for conducting such operations and removing tubular goods from wells. However, even with existing rig-less systems, significant time, effort and expense is often required for mobilization to a location, rig-up, rig-down and demobilization. Moreover, existing rig-less systems typically require the use of valuable offshore rig space, as well as the operation of pedestal cranes and/or other platform-mounted equipment in order to perform the plugging and abandonment operations.

Existing rig-less tubular removal systems also give rise to safety concerns. For example, when a crane is used, repeated stretching and relaxing of crane cables can occur during cutting and pulling operations. Such stretching and relaxing can cause such cables to fatigue, thereby making the cables more susceptible to breaking.

Thus, there is a need for an apparatus that eliminates many of the problems associated with conventional well operation techniques including, but not necessarily limited to, plugging and abandonment operations. Such apparatus should support wellbore tubular goods and related equipment that can be used down-hole in oil and gas wells, while requiring minimal surface area (e.g., deck space) yet providing many of the operational and safety benefits of conventional drilling and/or workover rigs.

SUMMARY OF THE INVENTION

The method and apparatus of the present invention improve performance during downhole cutting or section milling operations, such as during plugging and abandonment operations. The lifting assembly of the present invention can be beneficially utilized on satellite wells, caissons, derelict platforms, and environments having restricted workspaces which cannot accommodate larger conventional equipment installations. If desired, the apparatus of the present invention can be attached directly to a blowout preventer assembly.

The lifting assembly of the present invention comprises substantially planar upper table member and substantially planar lower base member. In the preferred embodiment, said upper table member defines a substantially flat upper surface and a generous keyseat slot formed in said upper table member. Similarly, said lower base member has substantially flat upper surface and a generous keyseat slot formed therein. The upper table member and lower base member are oriented substantially parallel to one another, while said keyseat slots are aligned with each other.

At least one lifting cylinder assembly is disposed between said upper table member and lower base member. Said at least one lifting cylinder assembly can be actuated to vary the distance between said upper table member and lower base member. In the preferred embodiment, telescoping elongate stabilization assemblies are also disposed between said upper table member and lower base member. Said telescoping elongate stabilization assemblies help to keep upper table member and lower base member, and the keyseat slots thereof, axially aligned.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description of the preferred embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, the drawings show certain preferred embodiments. It is understood, however, that the invention is not limited to the specific methods and devices disclosed. Further, dimensions, materials and part names are provided for illustration purposes only and not limitation.

FIG. 1 depicts an overhead perspective view of the lifting assembly of the present invention.

FIG. 2 depicts a front view of the lifting assembly of the present invention.

FIG. 3 depicts an overhead view of the lifting assembly of the present invention.

FIG. 4 depicts a side view of the lifting assembly of the present invention.

FIG. 5 depicts a sectional view of the lifting assembly of the present invention along line 5-5 of FIG. 4.

FIG. 6 depicts a front view of the lifting assembly of the present invention, in a retracted position, retrieving tubular goods from a wellbore.

FIG. 7 depicts a front view of the lifting assembly of the present invention, in an extended position, retrieving tubular goods from a wellbore.

FIG. 8 depicts a front view of the lifting assembly of the present invention, in a retracted position and installed on a blow out preventer assembly.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

FIG. 1 depicts an overhead perspective view of lifting assembly 10 of the present invention. Lifting assembly 10 comprises substantially planar upper table member 100 and substantially planar lower base member 110. In the preferred embodiment, upper table member 100 has substantially flat upper surface 101 and keyseat slot 102. Lower base member 110 has substantially flat upper surface 111 and keyseat slot 112. Upper table member 100 and lower base member 110 are oriented substantially parallel to each other, while upper keyseat slot 102 and lower keyseat slot 112 are aligned with each other.

Still referring to FIG. 1, a plurality of lifting cylinder assemblies 120 are disposed between upper table member 100 and lower base member 110. Additionally, elongate stabilization assemblies 130 are also disposed between said upper table member 100 and lower base member 110.

FIG. 2 depicts a front view of a lifting assembly 10 of the present invention. Upper table member 100 has substantially flat upper surface 101 and keyseat slot 102 formed in said upper table member 100. Lower base member 110 has substantially flat upper surface 111 and keyseat slot 112 formed in lower base member 110. Lifting cylinder assemblies 120 and elongate stabilization assemblies 130 are disposed between upper table member 100 and lower base member 110. Lifting cylinder assemblies 120 are connected at their upper extent to upper table member 100 with mounting brackets 123, and at their lower extent to lower base member 110 using mounting brackets 124.

FIG. 3 depicts an overhead view of lifting assembly 10 of the present invention. Upper table member 100 has substantially flat upper surface 101, and keyseat slot 102. In the preferred embodiment, keyseat slot 102 includes notches 105, while lifting padeyes 140 are disposed on said upper surface 101 and beneficially positioned near corners of said upper table member 110.

FIG. 4 depicts a side view of lifting assembly 10 of the present invention. Upper table member 100 has substantially flat upper surface 101, while lower base member 110 has substantially flat upper surface 111. Lifting cylinder assemblies 120 and elongate stabilization assemblies 130 are disposed between substantially parallel upper table member 100 and lower base member 110. Lifting cylinder assemblies 120 are connected at their top to upper table member 100 with mounting brackets 123, and at their bottom to lower base member 110 using mounting brackets 124.

FIG. 5 depicts a sectional view of lifting assembly 10 of the present invention along line 5-5 of FIG. 4. Lower base member 110 has substantially flat upper surface 111. Lifting cylinder assemblies 120, each comprising a cylinder barrel 121 and a telescoping, movable piston rod 122, are connected at their bottoms to substantially flat upper surface 111 of lower base member 110 using mounting brackets 124. Elongate stabilization assemblies 130, each comprising an outer housing 131 and an inner tube member 131, are connected at their bottoms to lower base member 110. Inner tube members 131 are movably received within said outer housings 131. Brace members 135 provide structural support for said elongate stabilization assemblies 130.

FIG. 6 depicts a front view of lifting assembly 10 of the present invention, in a retracted position and equipped with optional rotary swivel assembly 300, retrieving tubular goods 200 from a wellbore. Similarly, FIG. 7 also depicts a front view of lifting assembly 10 of the present invention, also equipped with rotary swivel 300, retrieving tubular goods 200 from a wellbore. Said rotary swivel can be secured within upper keyseat slot 102, and prevented from unwanted housing rotation, using notches 105. Lifting assembly 10 is beneficially positioned over said wellbore, such that tubular goods 200 can be received within aligned keyseat slots 102 and 112, as well as said wellbore.

FIG. 8 also depicts a front view of lifting assembly 10 of the present invention equipped with rotary swivel 300, retrieving tubular goods 200 from a wellbore. As depicted in FIG. 8, lifting assembly 10 is optionally connected directly to upper flange 401 of blowout preventer assembly 400.

In operation, lifting assembly 10 of the present invention can be efficiently and inexpensively transported to a work site. Due to its small foot print, robust design and maneuverability, lifting assembly 10 permits effective and efficient cutting and proof pulling functions. Lifting assembly 10, which is extremely portable allowing for quick mobilization and demobilization at a well site, can be used on many different types of locations including, without limitation, satellite wells, caissons, and conventional platform installations. As depicted in FIG. 8, lifting assembly 10 can be connected directly to a blowout preventer assembly.

Lifting assembly 10 has a small foot-print and a significant stroke length (in the preferred embodiment, up to 3 feet or greater) that permits precise downhole placement of blades or other cutting instruments during pipe-cutting operations. Further, due to the unique design of lifting assembly 10, excessive and undesirable movements commonly experienced when performing such functions with conventional lifting equipment (such as, for example, a platform crane) are minimized.

When a workstring is being utilized, such as for the cutting of pipe downhole, lifting assembly 10 of the present invention can be used to support, push and/or pull such workstring, and precisely place downhole cutting equipment within a well. If needed, rotary swivel 300 can be used to rotate said workstring, thereby translating torque to downhole equipment situated within a well. After a dowhole cut has been made, lifting assembly 10 of the present invention can also be used to pull on severed pipe, and remove such cut casing or other pipe from a well.

Lifting assembly 10 of the present invention includes generous keyway slots for easy workstring entry, as well as significant push and pull capabilities. Additionally, lifting assembly 10 can be used for single and/or multi-string cutting, single and/or multi-string section milling operations, and conventional milling applications utilizing a crane or other lifting equipment. Moreover, lifting assembly 10 of the present invention can be used for pull testing after mechanical, sand, or water jet cutting operations.

Lifting apparatus 10 of the present invention can accommodate an optional rotary table, and can be used with or without a marine swivel. When a workstring is being utilized, slips can be set on such workstring in order to hold the weight of said workstring. When desired, multiple lifting assemblies 10 can be vertically stacked and aligned above a wellbore for increased stroke and pulling capacity. An optional work deck can also be included when needed.

In the preferred embodiment, lifting assembly 10 of the present invention includes telescoping stabilization assemblies 130 that act to promote axial alignment and prevent torsion or “twisting” of the assembly (and, in particular, twisting of upper table member 100 relative to lower base member 110) during stroking of lifting cylinder assemblies 120. Further, said lifting assembly is hard-lined for simplified of connection and operation hydraulic control lines used to actuate lifting cylinder assemblies 120. Upper and lower deck slip placements permit multiple strokes for pull testing with spear equipment.

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.

Claims

1. An apparatus for conducting operations in a well comprising: a. a substantially planar base having a first keyway slot;b. a substantially planar table member having a second keyway slot, wherein said table member is substantially parallel to said base, and said first and second keyway slots are aligned with one another;c. at least one lifting assembly having an upper end and a lower end, wherein said lower end is connected to said base, and said upper end is connected to said table member; andd. at least one stabilization assembly disposed between said base and said table member.

2. The apparatus of claim 1, wherein said at least one lifting assembly comprises a hydraulic cylinder.

3. The apparatus of claim 1, further comprising a rotary assembly disposed on said table member.

4. The apparatus of claim 1, wherein said at least one stabilization assembly comprises: a. an elongate and substantially hollow outer member; andb. an elongate inner member, telescopically received within said elongate outer member.