Multi-Bar Scraper for Cleaning Marine Risers and Wellbores

Abstract

An instrument for the mechanical removal of corrosive buildup, deposits or scale from within a wellbore. A tubing-conveyed scraping blade and/or other abrading devices (50) has a collapsible maximum outer diameter by using a multi-bar mechanism (53, 54) to ensure physical contact with corrosive buildup, deposits or scale on surfaces of a surrounding wellbore, oil and gas tubular, or drilling/production marine riser (and, in particular, inner surfaces thereof). The multi-bar mechanism allows for a wide range of motion irrespective of the direction of loading and variable maximum outer diameter to clean corrosive buildup, deposits or scale from tubular goods with unknown configurations and/or dimensions.

Claims

1. A mechanical wellbore abrading assembly comprising: a) a housing member having a central through bore and an outer surface; b) a central mandrel disposed through said central through bore of said housing member; b) a plurality of abrasive members disposed along said outer surface of said housing, wherein said abrasive members are biased in an outward direction.

2. The mechanical wellbore abrading assembly of claim 1, wherein said housing member has a substantially cylindrical shape.

3. The mechanical wellbore abrading assembly of claim 1, wherein said plurality of abrasive members are disposed substantially around the entire circumference of said housing member.

4. The mechanical wellbore abrading assembly of claim 1, wherein said housing member is rotatable about said central mandrel.

5. The mechanical wellbore abrading assembly of claim 1, wherein said abrasive members comprise pads having a corrugated outer surface.

6. The mechanical abrading assembly of claim 1, wherein said abrasive members define a curved outer surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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.

[0020] FIG. 1 depicts a side perspective view of a scraper assembly of the present invention showing a plurality of bar mechanisms in a fully extended position.

[0021] FIG. 2 depicts a side sectional view of a scraper assembly of the present invention showing a plurality of bar mechanisms in a fully collapsed position and certain bar mechanisms fully extended position.

[0022] FIG. 3A depicts an overhead sectional view of a scraper assembly of the present invention showing a plurality of bar mechanisms in a fully collapsed position.

[0023] FIG. 3B depicts an overhead sectional view of a scraper assembly of the present invention showing a plurality of bar mechanisms in a fully extended position.

[0024] FIG. 4 depicts a side sectional view of a scraper assembly of the present invention disposed within a section of well casing.

[0025] FIG. 5 depicts a detailed view of the highlighted area depicted in FIG. 4.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0026] The application on which this application claims priority, U.S. Provisional Patent Application No. 62/094,507, filed Dec. 19, 2014, is hereby incorporated herein by reference.

[0027] FIG. 1 depicts a side perspective view of an adjustable scraper assembly 100 of the present invention. Adjustable scraper assembly 100 of the present invention can be conveyed into a wellbore from surface, and manipulated within said wellbore, via a tubular workstring (such as drill pipe, for example). Said scraper assembly can be included within a tool string assembly (that is, as part of a combination of tools for wellbore cleanout and validation) or, alternatively, as a standalone tool that is conveyed in and out of a wellbore with few or no other associated downhole tools.

[0028] In a preferred embodiment, adjustable scraper assembly 100 comprises a substantially cylindrical or tubular inner mandrel 10. Inner mandrel 10 can include pin-end (male) threaded connection member 11 and box-end (female) threaded connection member 12. Said threaded connection members 11 and 12 can be used to connect adjustable scraper assembly 100 to other components of a tool string, or as part of a conventional jointed tubular workstring (not shown).

[0029] A central through bore 13 extends substantially along the longitudinal axis of said inner mandrel 10, and provides a fluid flow path through adjustable scraper assembly 100. As depicted in FIG. 1, pin-end (male) threaded connection member 11 is oriented facing downward, while box-end (female) threaded connection member 12 is oriented facing upward in accordance with standard oilfield convention; however, it is to be observed that said connection members 11 and 12 can be switched or interchanged to satisfy particular applications or equipment configurations.

[0030] A housing member 20 having a central through bore is rotatably disposed on said inner mandrel 10. Although other shapes can be employed without departing from the scope of the invention, in a preferred embodiment housing member 20 has a substantially cylindrical shape defining an outer surface 21. Further, housing member 20 has a greater outer diameter than the outer diameter of central mandrel 10. A plurality of elongate slots 22 is disposed along the outer surface 21 of said housing member 20; said slots 22 are oriented substantially parallel to the longitudinal axis of inner mandrel 10.

[0031] In a preferred embodiment, slotted housing member 20 is affixed to a two-part mandrel and held in place by upper retention sub 30 and lower retention sub 40. In the embodiment depicted in FIG. 1, upper retention sub 30 generally comprises base member 33, retention collar 32 and a plurality of tapered and substantially planar support members 31 extending from said retention collar 32 to said base member 33. Similarly, lower retention sub 40 generally comprises base member 43, retention collar 42 and a plurality of tapered and substantially planar support members 41 extending from said retention collar 42 to said base member 43. Slotted housing member 20, top sub 30 and bottom sub 40 are all free to rotate around inner mandrel 10.

[0032] Upper retention sub 30 and lower retention sub 40 cooperate to retain slotted housing member 20 on inner mandrel 10 and prevent said slotted housing member 20 from traveling along the length of said inner mandrel 10. Further, the tapered configuration of lower retention sub 40 (and, more particularly, the radially outward-facing surfaces of support members 41) act as a guide to direct scraper assembly 100 into a wellbore and over ledges or restrictions when being conveyed into a wellbore. Similarly, the tapered configuration of upper retention sub 30 (and, more particularly, the radially outward-facing surfaces of support members 31) act as a guide to direct scraper assembly 100 out of a wellbore and past ledges or restrictions when being pulled out of a wellbore. The design of said upper retention sub 30 and lower retention sub 40 reduce the overall weight of scraper assembly 100.

[0033] Inner mandrel 10 can include pin-end (male) threaded connection member 11 and box-end (female) threaded connection member 12. Said threaded connection members 11 and 12 can be used to connect adjustable scraper assembly 100 to other components of a tool string, or as part of a conventional jointed tubular workstring (not shown).

[0034] A central through bore 13 extends substantially along the longitudinal axis of said inner mandrel 10, and provides a fluid flow path through adjustable scraper assembly 100. As depicted in FIG. 1, pin-end (male) threaded connection member 11 is oriented facing downward, while box-end (female) threaded connection member 12 is oriented facing upward in accordance with standard oilfield convention; however, it is to be observed that said connection members 11 and 12 can be switched or interchanged to satisfy particular applications or equipment configurations.

[0035] A housing member 20 having a central through bore is rotatably disposed on said inner mandrel 10. Although other shapes can be employed without departing from the scope of the invention, in a preferred embodiment housing member 20 has a substantially cylindrical shape defining an outer surface 21. Further, housing member 20 has a greater outer diameter than the outer diameter of central mandrel 10. A plurality of elongate slots 22 is disposed along the outer surface 21 of said housing member 20; said slots 22 are oriented substantially parallel to the longitudinal axis of inner mandrel 10.

[0036] In a preferred embodiment, slotted housing member 20 is affixed to a two-part mandrel and held in place by upper retention sub 30 and lower retention sub 40. In the embodiment depicted in FIG. 1, upper retention sub 30 generally comprises base member 33, retention collar 32 and a plurality of tapered and substantially planar support members 31 extending from said retention collar 32 to said base member 33. Similarly, lower retention sub 40 generally comprises base member 43, retention collar 42 and a plurality of tapered and substantially planar support members 41 extending from said retention collar 42 to said base member 43. Slotted housing member 20, top sub 30 and bottom sub 40 are all free to rotate around inner mandrel 10.

[0037] Upper retention sub 30 and lower retention sub 40 cooperate to retain slotted housing member 20 on inner mandrel 10 and prevent said slotted housing member 20 from traveling along the length of said inner mandrel 10. Further, the tapered configuration of lower retention sub 40 (and, more particularly, the radially outward-facing surfaces of support members 41) act as a guide to direct scraper assembly 100 into a wellbore and over ledges or restrictions when being conveyed into a wellbore. Similarly, the tapered configuration of upper retention sub 30 (and, more particularly, the radially outward-facing surfaces of support members 31) act as a guide to direct scraper assembly 100 out of a wellbore and past ledges or restrictions when being pulled out of a wellbore. The design of said upper retention sub 30 and lower retention sub 40 reduce the overall weight of scraper assembly 100.

[0038] A multi-bar (typically, a so-called “four-bar”) mechanism is disposed within each slot 22 of slotted housing member 20. A scraper member 50 is operationally attached to a coupler linkage of each such multi-bar linkage mechanism; said coupler linkage typically comprises an upper linkage bar member 53 and lower linkage bar member 54 that are operationally connected using a bias spring (not shown in FIG. 1) that acts to bias scraper member 50 in a substantially radially outward direction.

[0039] As depicted in FIG. 1, scraper members 50 comprise pad members having corrugated outer surfaces having alternating ridges and recesses. However, said preferred embodiment scraper members 50 are illustrative only; it is to be observed that blades or other abrading members can be used in place of (or in tandem with) scraper members 50. Scraper members 50 can be beneficially embody a curved or convex shape with a radius of curvature optimized to contact the maximum surface area of the surrounding inner surface of wellbore, oil and gas tubular good, or drilling/production marine riser intended to be cleaned.

[0040] FIG. 2 depicts a side sectional view of a scraper assembly 100 of the present invention. A central through bore 13 extends substantially along the longitudinal axis of said inner mandrel 10, and provides a fluid flow path through adjustable scraper assembly 100. Housing member 20 is rotatably disposed about the outer surface of said inner mandrel 10. A plurality of elongate slots 22 is disposed along the outer surface 21 of said housing member 20; said slots 22 extend substantially through housing member 20 and are oriented substantially parallel to the longitudinal axis of inner mandrel 10.

[0041] In a preferred embodiment, slotted housing member 20 is held in place by upper retention sub 30 and lower retention sub 40. Upper retention sub 30 generally comprises base member 33, retention collar 32 and a plurality of tapered and substantially planar support members 31 extending from said retention collar 32 to said base member 33. Lower retention sub 40 generally comprises base member 43, retention collar 42 and a plurality of tapered and substantially planar support members 41 extending from said retention collar 42 to said base member 43. Upper retention sub 30 and lower retention sub 40 cooperate to retain slotted housing member 20 on inner mandrel 10 and prevent said slotted housing member 20 from traveling along the length of said inner mandrel 10.

[0042] Still referring to FIG. 2, each multi-bar linkage mechanism comprises an upper linkage bar member 53 and lower linkage bar member 54, attached to scraper member 50, that are operationally connected by bias spring 55. In a preferred embodiment, each upper linkage bar member 53 is pivotally attached to sleeve housing 20 using pivot bolt 60; each upper linkage bar member 53 can rotate about a pivot axis passing through said pivot bolt 60. Each upper linkage bar member 53 is also pivotally attached to scraper member 50 using pivot bolt 61, as well as to bias spring 55 using pivot bolt 62. Each lower linkage bar member 54 is pivotally attached to sleeve housing 20 using pivot bolt 70; lower linkage bar member 54 can rotate about a pivot axis passing through said pivot bolt 70. Each lower linkage bar member 54 is also pivotally attached to scraper member 50 using pivot bolt 71 and to bias spring 55 using pivot bolt 72.

[0043] Springs 55 exert compression forces that bias upper linkage bar members 53 and lower linkage bar members 54 together, thereby forcing scraper member 50 in a substantially radially outward direction. In the embodiment depicted in FIG. 2, the “upper” set of bar mechanisms (that is, the bar mechanisms closest to top retention sub 30) are shown in a fully extended position, while the “lower” set of bar mechanisms (that is, the bar mechanisms closest to bottom retention sub 40) are shown in a fully collapsed or retracted position.

[0044] FIG. 3A depicts an overhead sectional view of scraper assembly 100 of the present invention with a plurality of bar mechanisms and attached scraper members 50 in a fully collapsed position (i.e., substantially the same configuration as the “lower” set of bar mechanisms depicted in FIG. 2). In the view depicted in FIG. 3A, bias springs 55 are partially extended, and scraper members 50 do not extend radially outward beyond the outer surface 21 of sleeve housing 20.

[0045] FIG. 3B depicts an overhead sectional view of a scraper assembly 100 with a plurality of bar mechanisms and attached scraper members 50 in a fully extended position (i.e., substantially the same configuration as the “upper” set of bar mechanisms depicted in FIG. 2). In the view depicted in FIG. 3B, bias springs 55 are retracted, and scraper members 50 protrude radially outward beyond the outer surface 21 of sleeve housing 20.

[0046] FIG. 4 depicts a side sectional view of an adjustable scraper assembly 100 of the present invention disposed within a section of well casing 200, while FIG. 5 depicts a detailed view of the highlighted area depicted in FIG. 4. In operation, adjustable scraper assembly 100 of the present invention can be conveyed into a wellbore from surface, via a tubular workstring (such as drill pipe, for example), and manipulated within well casing 200. Although other configurations can be used without departing from the scope of the present invention, mandrel 10 can be connected or made up to a tubular workstring, while central through bore 13 provides a flow channel for flow of fluids through said scraper assembly 100.

[0047] As depicted in FIGS. 4 and 5, well casing 200 has inner surface 201. In many circumstances including, without limitation, following well cementing operations, debris 300 can collect along said inner surface 201. Frequently, such debris 300 can comprise cement chunks, partially dried drilling mud particulates or other deposited solids. As discussed above, it is operationally beneficial to remove as much of debris 300 as possible from said inner surface 201.

[0048] Referring to FIG. 5, upper linkage bar member 53 is pivotally attached to sleeve housing 20 using pivot bolt 60 and can rotate about a pivot axis passing through said pivot bolt 60. Upper linkage bar member 53 is also pivotally attached to scraper member 50 using pivot bolt 61, and to bias spring 55 using pivot bolt 62. Similarly, lower linkage bar member 54 is pivotally attached to sleeve housing 20 using pivot bolt 70 and can rotate about a pivot axis passing through said pivot bolt 70. Lower linkage bar member 54 is also pivotally attached to scraper member 50 using pivot bolt 71 and to bias spring 55 using pivot bolt 72.

[0049] As said adjustable scraper assembly 100 is conveyed within well casing 200, bias springs 55 impart compression force on upper linkage bars 53 and lower linkage bars 54. Such compression forces act to bias scraper members 50 radially outward from slotted sleeve housing 20; in this configuration, the outwardly-facing surfaces of scraper members 50 contact inner surface 201 of well casing 200.

[0050] In a preferred embodiment, lower linkage bars 54 (positioned closer to the “down hole” end of scraper assembly 100) are longer than upper linkage bars 53 (positioned closer to the “up hole” facing end of scraper assembly 100). Such a configuration ensures that the multi-bar linkage systems (including, without limitation, scraper members 50) depress first from the down hole (leading) end of the coupler linkage when immovable obstructions or wellbore restrictions such as debris 300 are encountered.

[0051] When debris 300 (which is deposited on the inner surface 201 of well casing 200) is encountered, ridges 51 of scraper member 50 act to abrade or scrape said debris 300 from said inner surface 201. Shoulders 51a formed by the transition between ridges 51 and recesses 52 provide a sharp cutting surface to assist with said scraping action. When a restriction of the inner diameter of well casing 200 is encountered, bias spring 55 permits scraper member 50 to fully or partially collapse radially inward.

[0052] Said multi-bar mechanisms provide an adjustable, wide range of outer diameter coverage in substantially a 360-degree pattern around the outer surface 21 of slotted housing 20 and, thus, the outer circumference of said scraper assembly 100. To achieve 360-degree abrasive coverage of a wellbore, oil and gas tubular, or drilling/production marine riser annulus, multiple multi-bar linkage systems (generally comprising upper linkage bars 53, lower linkage bars 54, bias springs 55 and scraper members 50) are disposed within slots 22 of sleeve housing 20. Each slot 22 is positioned in phased relationship in order to overlap or ensure complete circumferential coverage when a scraper coupler linkage is fully extended. Moreover, multiple “stacked” scraper assemblies 100 can be run in tandem in order to further ensure 360-degree abrasive coverage of surrounding wellbore surfaces.

[0053] Said multi-bar mechanisms also apply significant force in an outward radial direction, thereby forcing scraper members 50 outward relative to housing 20. Such force is generally applied in a direction that is substantially perpendicular to the longitudinal axis of said scraper assembly 100 for effective abrasion of corrosive buildup, deposits and/or scale on surrounding surfaces. Central flow bore 13 extending through inner mandrel 10 permits fluid to be circulated through said scraper assembly 100 to circulate solids and debris out of a wellbore being mechanically cleaned with said scraper assembly 100.

[0054] 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.