US 3827487 A
A tubing injector base and a tubing stripper are mounted on the top flange of a blowout preventer assembly at the top of a well. The tubing stripper comprises a longitudinally split housing and a removable stripper rubber.
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Description (OCR text may contain errors)
United States Patent [191 Jackson et a1.
[ TUBING INJECTOR AND STUFFING BOX CONSTRUCTION  Inventors: John L. Jackson, Lafayette; John E.
Steinwinder, Broussard, both of La.
 Assignee: Baker Oil Tools, Inc., Los Angeles,
 Filed: Apr. 30, 1973  Appl. No.: 355,753
[451 Aug. 6, 1974 2,555,145 5/1951 McKinney 166/77 2,567,009 9/1951 Calhoun et a1. 166/77 3,116,793 1/1964 McStrauick i. 166/77 3,559,739 2/1971 Hutchison 166/77 Primary Examiner.lames A. Leppink Attorney, Agent, or FirmBernard Kriegel 5 7] ABSTRACT A tubing injector base and a tubing stripper are mounted on the top flange of a blowout preventer assembly at the top of a well. The tubing stripper comprises a longitudinally split housing and a removable stripper rubber.
6 Claims, 3 Drawing Figures TUBING INJECTOR AND STUFFING BOX CONSTRUCTION BACKGROUND OF THE INVENTION For various reasons, it may be desirable to inject and remove continuous lengths of conduit or tubing into and from a well through a blowout preventer. For example, it may be desirable to run or remove a length of tubing into or from a well bore for connection to or removal from subsurface apparatus operable by fluid pressure, such as a subsurface shutoff valve, subsurface well head equipment on offshore wells, or for other reasons.
An example of a tubing injector of the type here involved is illustrated on page 748 of the 1970-71 COM- POSITE CATALOG OF OIL FIELD EQUIPMENT & SERVICES. While the injector there shown is supported on legs, it is also known, for example, at offshore locations or platforms, the tubing injector unit may be supported on the tubing stuffing box, directly, instead of on legs, as shown in the catalog.
Such an installation of the tubing injector poses problems of stabilityor rigidity and, in addition, the tubing stuffing box is locatedbeneath the tubing injector base or platform. When the tubing stripper rubbers are to be removed and replaced, the connection or assembly of the injector with the tubing stufflng box must be broken down. In such an assembly, moreover, sufficient height or space must usually be afforded to enable removal of the stripper rubber from the stufflng box assembly, which has, heretofore, involved unthreading a retainer nut from the injector assembly, thus requiring axial space for threading and unthreading the retainer nut and other stufflng box components.
SUMMARY OF THE INVENTION To further improve the arrangement and simplicity of the tubing injector and stuffing box combination, by conserving space and saving time when the stuffing box stripper rubber is to be replaced, the stuffing box top sub or body is longitudinally split so as to be applicable and removable laterally, thereby eliminating the need for axial freedom or space for threaded connection and removal of the top sub and other connectors, such as the retainer nut referred to above. The longitudinally split top sub or body parts have bolt receiving side portions enabling the body parts to be interconnected and disassembled.
This invention possesses many other advantages, and has other purposes which may be made more clearly apparent from a consideration of the form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. They will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed descriptions are not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation of a tubing injector and stuffing box supported on a blowout preventer, in accordance with the invention;
FIG. 2 is an enlarged, fragmentary vertical section, as taken on the line 22 of FIG. 1; and
FIG. 3 is a top view, as taken on the line 33 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT As seen in the drawing a tubing injector assembly I and a stufflng box assembly S are supported on a blowout preventer assembly B, the latter, as is well known, being suitably located on a well drilling or production rig and being connected to a well pipe, such as a well casing, not shown, to enable various operations to be performed through the blowout preventer which enables the well to be sealed off at the blowout preventer.
The details of the tubing injector I are not germane to the present invention, and an exemplary tubing injector is that identified above and shown in the COM- POSITE CATALOG OF OIL FIELD EQUIPMENT & SERVICES. This tubing injector comprises a base or platform and an upwardly extendedhousing 11 for drive means (not shown), whereby a length of tubing T may be fed or injected into and removed from the well, the tubing being suitably stored on a supply reel, for example. In the illustrated case, the tubing T extends over an arched guide means 12 supported above the housing 11 on brace means 13. The injector assembly also includes suitable support and jack means 14, all as is well known, so as to require no detailed disclosure herein.
Referring to FIG. 2, the stufflng box means or assembly S is shown as comprising a base or body member 15 of tubular form. The body 15 has a lower section 16 disposed within an opening 17 in the base or platform 10 of the tubing injector and having a radially outwardly extended flange 18. This flange 18 seats in an annular cavity 19 of the platform 10 formed by a flange section 20. The flange 18 and the flange section 20 are interconnected and connected to an upper, radially outwardly projecting flange 21 of the blowout preventer means B by a number of circumferentially spaced bolts 22 which extend through the flanges 18, 20 and 21. A packing or seal ring 23 of annular form is disposed in opposed, annular seal cavities 24, in the lower face of the flange 18, and 25, in the upper face of the flange 21. This seal ring 23 provides a seal to prevent leakage between the flanges 18 and 21 from an axially extended bore 26 in the blowout preventer B and 27 in the stufflng box body 15.
Within the stuffing box body 15 is a cylindrical section 28 which defines a cylinder head, through which a cylindrical skirt portion 29 of an annular piston 30 is reciprocable. Between the skirt 29 and the cylinder head 28 is a seal ring 31, and the annular piston 30 has an external ring seal 32 slidably and sealingly engaging an upper cylinder wall 33, in the body 15 above the cylinder head 28. Between the lower sealing ring means 30 and the upper sealing ring means 32 is a chamber 34 to which pressure fluid is admissible via a radial port 35 in the body to act on the piston 30 for forcing it upwardly.
The body 15 has a threaded neck 36, on which is threaded a tubular cylinder adaptor 37. Within the adaptor 37 is a cylindrical section 38 having an internal seal ring 39 slidably and sealingly engaging the outer surface of a cylindrical, upward extension 40 of the piston 30. The space 41 between the piston 30 and the cylindrical section 38 is vented via a port 42 extending radially through the adaptor 37.
Reciprocable within the cylinder adaptor 37 is a wear bushing 43 having a skirt portion 44 extending downwardly into the upward extension 40 of the piston 30 and an upper, radially outwardly projecting flange 45 engageable by the upper end 46 of the extension 40 so as to be moved upwardly by the latter, under the influence of fluid pressure admitted to the piston chamber 34.
Disposed above the wear bushing 43 are stripper means 50, comprising a stripper rubber in the form of a tubular body 51 of elastomeric material adapted to be axially and circumferentially deformed into engagement with the tubing which extends through the central opening 52 therethrough. Various forms of such stripper rubbers are known, but the rubber illustrated is longitudinally split and has metal end ring sections 53 forming frusto-conical washers engaged with an upwardly facing companion surface 54 on the wear bushing 43 and an opposed downwardly facing surface 55 at the lower end of an upper wear bushing 56. This wear bushing 56 has a bottom flange 57 projecting radially outwardly and providing an upper shoulder 58. Interposed between the flanges 45 and 57 of the wear bushings 43 and 56 and surrounding the stripper rubber 51, in the illustrated assembly, is a so-called energizer, of a known form, comprising an elastomeric body 59 having a coiled spring 60 embedded therein, and adapted to assist in forcing the stripper rubber 51 into engagement with the tubing.
For purposes of retaining the stripper rubber 51, the energizer 59 and the wear bushing 56 in assembly on cylinder adaptor 37 and enabling axial loading of the stripper rubber and the energizer between the flanges 45 and 57 of the wear bushings 43 and 56, while facilitating disassembly and replacement of stripper rubbers, a top sub or body 70 is provided, comprising complemental body half-parts 70 and 71 (see FIG. 3) joined together at a longitudinally extended parting line by fasteners 72 which extend through radially outwardly projecting flanges 70a and 71a on the body half-parts.
Thus, when the stripper means are assembled, as seen in FIG. 2, pressure fluid applied to the piston chamber 34 acts upwardly on the piston 30. As the piston 30 is moved upwardly, its upward extension 40 moves the flange 45 of the wear bushing 43 towards the flange 57 of the wear bushing 56, thereby axially deforming the energizer 59 and stripper rubber 51 and causing radial expansion of the stripper rubber towards the tubing for sliding engagement with the latter.
As will now be apparent, replacement of the stripper rubber 51 may be easily accomplished by lateral disassembly of the body parts 76 and 71. In addition, the in terconnection of the base flange 18 of the stuffing box body 15 and the platform 10 of the tubing injection, provides a rigid assembly with the blowout preventer B.
I. In combination, tubing injector means for running and retrieving a length of tubing into and from a well,
and stufflng box means for stripping the tubing, said tubing injector means having a platform and said stuffing box means having a body connected to said platform, blowout preventer means below said tubing injector means, said blowout preventer means having a top flange, said body of said stuffing box means having a bottom flange, and fastener means connecting said platform of said tubing injector means with said top flange of said blowout preventer means and said bottom flange of said body of said stufflng box means.
2. In the combination of claim 1, said stufflng box means including resiliently deformable stripper means, and means for axially and radially deforming said stripper means into engagement with a tubing extending through said stufflng box means and said tubing injector means.
3. In combination, tubing injector means for running and retrieving a length of tubing into and from a well, and stufflng box means for stripping the tubing, said tubing injector means having a platform and said stuffing box means having a body connected to said platform, said stufflng box means including resiliently deformable stripper means, and means for axially and radially deforming said stripper means into engagement with a tubing extending through said stufflng box means and said tubing injector means, said stufflng box means including laterally separable means confining said stripper means between said tubing injector means and said stuffing box means.
4. In combination, tubing injector means for running and retrieving a length of tubing into and from a well, and stufflng box means for stripping the tubing, said tubing injector means having a platform and said stuffing box means having a body connected to said platform, said stufflng box means including an upper wear bushing having a lower end flange and a lower wear bushing having an upper end flange, resiliently deformable stripper means between said end flanges, and means for forcing one of said wear bushings towards the other of said wear bushings to deform said stripper means between said end flanges.
5. In the combination of claim 4, said stufflng box means including laterally separable means confining said stripper means between said tubing injector means and said stufflng box means.
6. In the combination of claim 4, said stuffing box means also including longitudinally split body sections having means coengageable with said wear bushings to limit axial separation, and means separably interconnecting said longitudinally split body sections.