GB2236129A - Sealing assembly for subterranean well packing unit - Google Patents
Sealing assembly for subterranean well packing unit Download PDFInfo
- Publication number
- GB2236129A GB2236129A GB9019051A GB9019051A GB2236129A GB 2236129 A GB2236129 A GB 2236129A GB 9019051 A GB9019051 A GB 9019051A GB 9019051 A GB9019051 A GB 9019051A GB 2236129 A GB2236129 A GB 2236129A
- Authority
- GB
- United Kingdom
- Prior art keywords
- cone
- rings
- packer
- ring
- sealing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000007789 sealing Methods 0.000 title claims abstract description 61
- 238000012856 packing Methods 0.000 title claims abstract description 19
- 238000001125 extrusion Methods 0.000 claims abstract description 24
- 239000003566 sealing material Substances 0.000 claims abstract description 12
- 239000011368 organic material Substances 0.000 claims abstract description 9
- 238000010008 shearing Methods 0.000 claims abstract description 5
- 229920000049 Carbon (fiber) Polymers 0.000 claims abstract description 4
- 239000004917 carbon fiber Substances 0.000 claims abstract description 4
- 230000006835 compression Effects 0.000 claims description 5
- 238000007906 compression Methods 0.000 claims description 5
- 239000004696 Poly ether ether ketone Substances 0.000 claims description 3
- 229920002530 polyetherether ketone Polymers 0.000 claims description 3
- 230000001151 other effect Effects 0.000 claims 1
- 239000000463 material Substances 0.000 abstract description 9
- 230000000694 effects Effects 0.000 abstract description 7
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 abstract description 2
- 238000010276 construction Methods 0.000 description 4
- 238000007142 ring opening reaction Methods 0.000 description 3
- 239000000835 fiber Substances 0.000 description 2
- 229910001141 Ductile iron Inorganic materials 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 239000013536 elastomeric material Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000007779 soft material Substances 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/12—Packers; Plugs
- E21B33/1208—Packers; Plugs characterised by the construction of the sealing or packing means
- E21B33/1216—Anti-extrusion means, e.g. means to prevent cold flow of rubber packing
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Containers And Plastic Fillers For Packaging (AREA)
- Gasket Seals (AREA)
Abstract
Extrusion of organic sealing element material (20) between inner surfaces of upper and lower cone elements (12, 14) and the exterior of a tubular body portion (10) is eliminated by forming a generally radial surface (12b, 14b) on the inner end of each of the upper and lower cone elements (12, 14) and inserting a carbon fiber filled organic material (22) in the resulting annular chamber. Extrusion of the organic material (20) between the inclined conical surfaces (12a, 14a) of each cone element (12, 14) and the cooperating surface (16a) of the cone ring (16) is minimized by utilizing the forces exerted by the compressed sealing material (20) of the packing element to effect the shearing of the vertex portion of a packer ring (18) along a plane that corresponds exactly to the inclined conical surface (12a, 14a) of the cone element (12, 14). <IMAGE>
Description
SEALING ASSEMBLY FOR SUBTERRANEAN WELL PACRING UNIT
BACKGROUND OF THE INVENTION 1 FIELD OF THE TnJpMaTC"xT The invention relates to an improved sealing assembly for a subterranean well packing unit, and particularly to a sealing assembly that minimizes extrusion of organic sealing material commonly employed in such pacing unit.
2. SUMMARY OF THE PRIOR ART: As will be later described in connection with Fig. 1, prior art sealing assemblies have involved a sealing sleeve formed of an organic sealing material which snugly surrounds a tubular body portion of a packer or bridge plug for a subterranean well. The sealing sleeve is subjected to substantial compressive forces by upper and lower cone elements having oppositely disposed inclined surfaces.
Intermediate the inclined surfaces of the cone elements and the original end surface of the sealing sleeve, a cone ring and a packer ring are mounted. Both of these rings have to be C-rings to permit their expanison. The cone ring has an inclined surface that is cooperable with the inclined surface on the adjacent cone element.
An annular tongue and groove connection effects the connection of each cone ring to the packer ring. Each packer ring has an inclined surface which is engagable with the end surface of the sealing sleeve.
As the upper and lower cone elements are moved axially relative to each other so as to bring them closer together, an increasing compressive force is applied te the sealing sleeve. At the same time, the cone rings and packer rings are expanded radially outwardly by the inclined surfaces of the upper and lower cone elements t..o.e.. the packer or bridge plug is fully set and the sealing sleeve is compressed between the tubular body and the bore of a well conduit, the substantial compression forces on the organic sealing element causes a gradual extrusion of the material of such element between the inner face of the upper and lower cone elements and the outer surface of the tubular body.An additional major extrusion path is provided between the inclined surface of the cone ring and the cooperating inclined surface of the respective upper or lower cone element because of the C-ring construction of the cone ring. Such extrusion path effects a gradual reduction in the compressive forces trapped in the organic sealing element, hence reducing the sealing efficiency of such element.
In the conventional construction, the cone ring normally has a slightly smaller internal diameter than the packer ring. Since both the packer rings and cone rings are fabricated as C-rings, there is an inherent path for extrusion of the organic material of the sealing sleeve as compressive forces are applied to such sleeve.
Numerous solutions have been proposed for this extrusion problem in the past, but none have been fully effective. There is a definite need therefore, for a sealing assembly which will effectively prevent extrusion of an organic sealing element along the extrusion Filths - pre'7iousl': mentioned.
SUMMARY OF THE INVENTION
The present invention provides a sealing assembly for a subterranean well packing unit as claimed in each of claims 1 to 5, to which reference is directed.
A preferred embodiment of the invention employs a conventional tubular body on which are mounted upper and lower cone elements for relative axial movement.
Between the cone elements a sleeve of a conventional organic, elastomeric sealing material is snugly mounted on the exterior of the tubular body. Each of the upper and lower cone elements have oppositely disposed inclined conical surfaces which, in the unset position of the upper and lower cone elements are not normally in engagement with the sealing sleeve.
The spaces intermediate the oppositely inclined conical surfaces on the upper and lower cone elements and the axial ends of the sealing sleeve are occupied by a pair of cone rings and packer rings. The cone rings and packer rings are of C-ring construction. Each cone ring is of generally trianqular cross-section and has an inclined surface that mates with the inclined surface on the adjacent one of the upper and lower cone elements.
Each packer ring has an inclined surface engaged with the ado accent end vace Cf the organic sealing element in the unset position of the sealing assembly. An annular tongue is provided in one of the packer rings and cone rings and an annular groove cooperable with such tongue is provided in the other of these rings, thus securing each cone ring and the adjacent packer ring for co-movement.
In accordance with this invention, each packer ring has a smaller internal diameter than the adjacent cone ring and is fabricated from a relatively soft metallic material. Thus, a vertex portion of the packer ring extends radially inwardly beyond the cone ring and, as compressive force is applied to the organic material of the sealing sleeve, such material exerts a substantial force against such vertex portion and readily effects the shearing off of such vertex portion along a plane that corresponds exactly to the inclination of the inclined surface of the adjacent cone element. Thus, as the cone rings and packer rings ride radially outwardly respectively on the upper and lower cone elements, the surface newly created by the shearing action effects a seal with the adjacent upper or lower cone element and substantially reduces this extrusion path.
To further improve the anti-extrusion property of the sealing assembly, the oppositely inclined surfaces of the upper and lower cone elements are terminated in a generally radial inner surface, thus defining annular cf t=il,rl ?M8 ~r.f~urati~r.
respectively between the upper and lower cone elements and the adjacent cone rings in the unset position of the sealing element. An annular ring of carbon fiber filled organic sealing material, such as polyetheretherketone, is inserted in the aforementioned annular chamber and has a triangular cross-section conforming to that of the chamber. The fiber filling of this material substantially eliminates its extrusion. Thus, as the compression of the sealing sleeve is effected by the relative movement of the upper and lower cone elements toward each other, this triangular cross-section sealing element effects a sealing engagement between the radial, inner surface provided on each of the upper and lower cone elements and the adjacent external surface of the tubular body. Thus, the second major path for extrusion loss of material of the organic sealing element is effectively eliminated.
Further objects and advantages of the invention will be readily apparent to those skilled in the art from the following detailed description of a preferred embodiment of the invention with reference to the drawings.
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 is a vertical quarter-sectional view of an existing sealing assembly for a subterranean well packirg ut, cn which th major seal extrusion leakage paths are indicated.
Fig. 2 is a vertical quarter-sectional view of an extrusion of a sealing assembly for a subterranean well packing unit embodying this invention, with the sealing assembly shown in its unset or uncompressed condition.
Fig. 3 is a view similar to Fig. 2 but showing the sealing assembly in its set or compressed position in engagement with the wall of a well conduit.
Fig. 4 is an enlarged view of that portion of Fig. 2 contained within the dotted line circle.
Fig. 5 is an enlarged view of that portion of Fig. 3 contained within the dotted line circle.
DESCRIPTION OF PREFERRED EMBODIMENT
Referring to Fig. 1, there is illustrated a conventional sealing assembly for a packer or bridge plug employed in a subterranean well. The sealing assembly is shown in its expanded position and a tubular mass of organic sealing material is compressed into sealing engagement between the exterior of a body tube and the bore of a well conduit such as the casing. The cresisn cf ths c-ga.; z sealin material IS effected by relative movement of upper and lower cone elements toward each other which effect the concurrent movements of a cone ring and packer ring mounted between each axial end ot tne sealing material and the respective upper or lower cone element.The cone rings and packer rings are necessarily of C-ring configuration because the one ring has an inclined surface engagable with a similarly shaped surface formed on the adjacent upper or lower cone element which expands the cone rings and packer rings outwardly.
The packer ring is moved outwardly by the C-ring through the inner engagement through an annular tongue and groove connection.
When the sealing material is in it compressed condition, there are two major paths for extrusion of such material. The first path, indicated by the arrow
A, is between the lower end of the packer ring and then through the C-ring opening of the cone ring.
The second major extrusion path, indicated by the arrow B, is between the internal surface of the upper and lower cones and the adjacent external surface of the tubular body on which such cones are mounted.
It is therefore readily apparent that in this prior art construction, a substantial quantity of the organic sealing material may be extruded through the leakage paths A and B and thus the compressive forces existing in the sealing material will be gradually reduced, thus reducing the sealing effectiveness of such material.
Turning now to Figs. 2 - 5, a sealing assembly embodying this invention is illustrated. In Fig. 2, the sealing assembly is shown n its unset =r uncompressed position, while in Fig. 3, the sealing assembly is shown in its set or compressed position.
The sealing assembly embodying this invention is mounted between the tubular body 10 of a packer, bridge plug or similar well tool and the bore of a well conduit
C and comprises an annular mass of an organic, elastomeric material 20 which is snugly engagable with the exterior external surface 10a of the tubular body 10. Such annular mass will hereinafter be referred to as a sealing sleeve.
Adjacent each end of the sealing sleeve 20, an upper cone element 12 and a lower cone element 14 are respectively provided. Such cone elements have oppositely inclined, facing conical surfaces 12a and 14a.
Intermediate the upper and lower cone elements 12 and 14 and the adjacent axial ends of the sealing sleeve 20, an upper pair and a lower pair of cooperating rings 16 and 18 are provided, respectively. The rings 16 are commonly referred to as cone rings and are of triangular shaped cross-section and have inclined conical surfaces 16a which conform to and are engaged by the inclined conical surfaces 12a and 14a of the upper and lower cone elements 12 and 14 respectively. The rings i8 are commonly referred to as packer rings and again are of triangular cross-sectional configuration and have opposed inclined conical surfaces 18a engagable with the opposite axial ends of the sealing sleeve 20 as the upper and lower cone elements 12, 14 are moved relatively towards each other.Both the rings 16 and 18 ars of C-ring configuration to permit their radial zx-znicn as the upper ar.d ower cone elements '2 and 14 move toward each other. Each pair of cone rings 16 and 18 are connected for co-movement by an annular tongue 16b formed on the cone ring 16 and an annular groove 18b formed in the packer ring 18 and receiving the tongue 16b therein in snug fitting relationship.
In accordance with this invention, the lowermost and uppermost portions respectively of the inclined conical surfaces 16a of the upper and lower cone elements 12 and 14 are both provided with generally radial surfaces 12b and 14b respectively. These surfaces each cooperate with the adjacent inclined conical surface 16a of the adjacent cone ring 16 to define an annular chamber of generally triangular cross-sectional configuration, a continuous auxiliary ring 22 of a fiber-filled organic material being snugly inserted in such annular chamber.
The material employed for the ring 22 is preferably polyetheretherketone which is filled with carbon fibers constituting on the order of 30% of the total mass of the ring 22.
It will be noted from Figs. 2 and 4 that the inner end or the vertex. portion 18c of each packer ring extends radially inwardly beyond the vertex 16c of the cone rings 16. This dimensional relationship is provided for a specific purpose that will become apparent when we turn to Fig. 3 which shows the seal assembly embodying this invention in its set or compressed position.
As the compressive forces are exerted on the sealing sleeve 20 by the relative axial movement of the cone 12 elements and 14 toward each other, such compressive forces are transmitted by the sealing sleeve 20 to the vertex portions 18c of the packer ring 18. Since the packer ring 18 is formed of a relatively soft material, such as ductile iron, this vertex portion 18c will be sheared off in the manner indicated in Fig. 5 and the shearing wilr take place along a plane 18d that is exactly parallel to the inclination of the inclined surface 12a or 14a of the adjacent cone element 12 or 14 as the case may be. Thus, a seal is provided between all portions of the packer ring 18 and the inclined cone surfaces 12a or 14a except at the place where the opening in the C-ring configuration of the packer ring 18 exists.As indicated in Figs. 2 and 3, the C-ring openings 18e in the packer rings 18 are 180' displaced from the C-ring openings 16e in the associated cone rings 16.
Of equai importance is the fact that the compressed organic material of the sealing sleeve 20 will exert a force directly upon the auxiliary sealing ring 22 and prevent extrusion between the inner cylindrical surfaces of the cone elements 12 and 14 and the outer surface of the tubular body 10. The sealing sleeve 20 is, of course, expanded into intimate engagement with the .n.rnGl wall of a well conduit, such as the casing C.
it Will therefore be readily apparent to those skilled in the art that a seal assembly embodying this invention effectively substantially reduces the extrusion paths for extrusion of an organic sealing element due to its compression by the upper and lower cones during the setting operation.
Although the invention has been described in terms of specified embodiments which are set forth in detail, it should be understood that this is by illustration only and that the invention is not necessarily limited thereto, since alternative embodiments and operating techniques will become apparent to those skilled in the art in view of the disclosure. Accordingly, modifications are contemplated which can be made without departing from the spirit of the described invention.
Claims (5)
1. A sealing assembly for a subterranean well packing unit comprising, in combination: a tubular body element; a packing sleeve formed of a deformable organic material and snugly surrounding an axial portion of the exterior of said tubular body element;
upper and lower cone elements freely surrounding said tubular body element at opposite axial ends of said packing sleeve and having oppositely inclined, facing conical surfaces respectivelv axially spaced from said packing sleeve;
a pair of cone C-rings respectively cooperable with said oppositely inclined conical surfaces of said upper and lower cones to be urged radially outwardly and axially toward each other by relative axial movement of said cone elements toward each other, said cone C-rings respectively having generally radial, facing surfaces;;
a pair of packer C-rings respectively connected to, and abutting said facing surfaces of, said cone C-ringsy whereby the axial and radial movements of said cone rings are transferred to said packer C-rings;
said packer C-rings having opposed inclined conical surfaces respectively engagable with opposite axial ends of said packing sleeve, whereby axial movement of said cone rings toward each other produce a compression of said packing sleeve to deform said packing sleeve radially and axially;;
each said inclined conical surface on said packer
C-rings forming an inner vertex portion extending radially inwardly past the inner end of the adjacent said cone C-ring, whereby, in use, the compressive force generated by relative axial movement of said cone rings toward each other effects a shearing of said vertex portion of each said packer C-ring to produce a surface on each said packer C-ring snugly conforming to the adjacent one of said oppositely inclined conical surfaces on said upper and lower cone elements.
2. A sealing assembly as claimed in Claim 1 wherein each said oppositely inclined conical surfaces on said cone elements terminate at their radially inner ends in a generally radial surface, thereby defining an annular chamber of triangular cross-section; and
a ring of extrusion resistant organic sealing material disposed in said annular chamber and compressible by deformation of said sealing sleeve into sealing engagement with the exterior of said tubular body and said generally radial surface on the adjacent cone ring.
3. A sealing assembly for a subterranean well packing unit comprising, in combination:
a tubular body element;
a packing sleeve formed of a deformable organic material and snugly surrounding an axial portion of the exterior of said tubular body element;
upper and lower cone elements freely surrounding sad tubulr body ..rro A opposite axial ends of said packing sleeve and having oppositely inclined, facing conical surfaces respectively axially spaced from said packing sleeve;
a pair of cone C-rings respectively cooperable with said oppositely inclined conical surfaces on said upper and lower cone rings to be urged radially outwardly and axially toward each other bv relative axial movement of said cone elements toward each other, said cone C-rings having generally radial, facing surfaces;;
a pair of packer C-rings respectively secured to and abutting said facing surfaces of said cone elements, whereby the axial and radial movements of said cone
C-rings are transferred to said packer C-rings;
said packer C-rings having opposed inclined conical surfaces respectively engagable with opposite axial ends of said packing sleeve, whereby axial movement of said cone elements toward each other produces a compression of said packing sleeve to deform said packing sleeve radially and axially;
each said oppositely inclined conical surfaces on said cone elements terminating at their radially inner portions in a generally radial surface, thereby defining an annular chamber of triangular cross-section; and
a ring of extrusion resistant, organic sealing material disposed in said annular chamber and compressible by deformation of said sealing sleeve into sealing engagement with tre e-r or of said tubular body and said generally radial surface on the adjacent cone element.
4. A sealing assembly as claimed in Claim 2 or 3 wherein said extrusion resistant organic material comprises polyetheretherketone containing carbon fibers.
5. A sealing assembly as claimed in Claim 1, 2 or 3 wherein the gap in each cone C-ring is displaced by about 180 from the gap in the adjacent packer C-ring.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US40166489A | 1989-08-31 | 1989-08-31 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9019051D0 GB9019051D0 (en) | 1990-10-17 |
| GB2236129A true GB2236129A (en) | 1991-03-27 |
Family
ID=23588690
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9019051A Withdrawn GB2236129A (en) | 1989-08-31 | 1990-08-31 | Sealing assembly for subterranean well packing unit |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2024347C (en) |
| GB (1) | GB2236129A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5467822A (en) * | 1991-08-31 | 1995-11-21 | Zwart; Klaas J. | Pack-off tool |
| GB2396368A (en) * | 2002-12-19 | 2004-06-23 | Schlumberger Holdings | Rubber sleeve to protect moving components from encrusting mineral deposits |
| CN104302868A (en) * | 2012-05-15 | 2015-01-21 | 贝克休斯公司 | Packing element backup system |
| EP2994605A4 (en) * | 2013-05-07 | 2017-01-18 | Freudenberg Oil & Gas, LLC | Expandable packing element and cartridge |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2015123020A (en) | 2012-12-21 | 2017-01-27 | Ресорс Комплишн Системз Инк. | MULTISTAGE WELL INSULATION AND HYDRAULIC RIP |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1012397A (en) * | 1962-04-30 | 1965-12-08 | Baker Oil Tools Inc | Improvements in or relating to well packers |
| GB2069571A (en) * | 1980-02-19 | 1981-08-26 | Baker Int Corp | Seals for well tools |
| GB2106957A (en) * | 1981-09-25 | 1983-04-20 | Dresser Ind | Packer sealing assembly |
| US4611658A (en) * | 1984-09-26 | 1986-09-16 | Baker Oil Tools, Inc. | High pressure retrievable gravel packing apparatus |
| US4745972A (en) * | 1987-06-10 | 1988-05-24 | Hughes Tool Company | Well packer having extrusion preventing rings |
-
1990
- 1990-08-30 CA CA 2024347 patent/CA2024347C/en not_active Expired - Lifetime
- 1990-08-31 GB GB9019051A patent/GB2236129A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1012397A (en) * | 1962-04-30 | 1965-12-08 | Baker Oil Tools Inc | Improvements in or relating to well packers |
| GB2069571A (en) * | 1980-02-19 | 1981-08-26 | Baker Int Corp | Seals for well tools |
| GB2106957A (en) * | 1981-09-25 | 1983-04-20 | Dresser Ind | Packer sealing assembly |
| US4611658A (en) * | 1984-09-26 | 1986-09-16 | Baker Oil Tools, Inc. | High pressure retrievable gravel packing apparatus |
| US4745972A (en) * | 1987-06-10 | 1988-05-24 | Hughes Tool Company | Well packer having extrusion preventing rings |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5467822A (en) * | 1991-08-31 | 1995-11-21 | Zwart; Klaas J. | Pack-off tool |
| GB2396368A (en) * | 2002-12-19 | 2004-06-23 | Schlumberger Holdings | Rubber sleeve to protect moving components from encrusting mineral deposits |
| GB2396368B (en) * | 2002-12-19 | 2006-07-05 | Schlumberger Holdings | Technique for preventing deposition products from impeding the motion of a movable component |
| US7108065B2 (en) | 2002-12-19 | 2006-09-19 | Schlumberger Technology Corporation | Technique for preventing deposition products from impeding the motion of a movable component |
| CN104302868A (en) * | 2012-05-15 | 2015-01-21 | 贝克休斯公司 | Packing element backup system |
| CN104302868B (en) * | 2012-05-15 | 2017-06-27 | 贝克休斯公司 | Pack-off element supporting system |
| EP2994605A4 (en) * | 2013-05-07 | 2017-01-18 | Freudenberg Oil & Gas, LLC | Expandable packing element and cartridge |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9019051D0 (en) | 1990-10-17 |
| CA2024347A1 (en) | 1991-03-01 |
| CA2024347C (en) | 2001-05-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |