US2762638A - Stripper and seal device for well heads - Google Patents

Description

Sept. 11, 1956 c. 0. BROWN STRIPPER AND SEAL DEVICE FOR WELL HEADS 3 SheetsSheet 1 Filed Oct. 25, 1952 C. (TB/"Own INVENTOR.

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A TTORNEY Sept. 11, 1956 c. c. BROWN 2,762,633

STRIPPER AND SEAL DEVICE FOR WELL HEADS Filed Oct. 25, 1952 s Sheets-Sheet 2 C. C. Bro vvn INVENTOR.

A TTORNEY p 11, 1956 c. c. BROWN STRIPPER AND SEAL DEVICE FOR WELL HEADS I 5 Sheets-Sheet 3 C C Bro wn INVENTOR.

Filed Oct. 25, 1952 as 8/ A amm -aao/oa dill ATTORNL') United States Patent F STRIPPER AND SEAL DEVICE FOR WELL HEADS Cicero C. Brown, Houston, Tex.

Application October 25, 1952, Serial No. 316,875

7 Claims. (Cl. 286-163) This invention relates to well head equipment and particularly to a pipe stripper and seal device for use in well heads.

A principal object of this invention is to provide a pipe stripper and seal device which is adapted to be installed in a well head and through which well pipe, such as casing or tubing, may be drawn while maintaining the well under full and safe control under all pressure conditions which may develop in the well.

Another object is to provide a stripper and seal device which will form an effective fluid-tight seal about pipe being drawn therethrough, and which is resiliently expandible to permit passage therethrough of enlargements on the pipe.

A further object is to provide a stripper and seal device which will eflectively prevent blow outs while pipe is being withdrawn from a well.

A more specific object is to provide a stripper and seal device which includes a flexible resilient sleeve through which the pipe and any enlargements thereon may be drawn while being closely embraced by the sleeve, and a segmental metallic core mounted in the bore of the sleeve which is expandible with the sleeve to pass enlargements on the pipe but which will contract in response to unbalanced well pressures acting on the resilient sleeve to form a substantially solid annular abutment in the bore of the sleeve which will engage enlargements on the pipe to prevent further withdrawal of the pipe while the unbalanced well pressure condition exists.

Other and more specific objects and advantages of this invention will become readily apparent from the following detailed description when read in conjunction with the accompanying drawings which illustrate useful embodiments in accordance with this invention.

In the drawings:

Fig. 1 is an exploded perspective view in longitudinal section of a stripper and seal device in accordance with one embodiment of this invention;

Fig. 2 is a longitudinal quarter-sectional view of a casing head showing the stripper and seal device installed therein and a pipe being drawn through the stripper and seal device;

Fig. 3 is a fragmentary sectional view of the stripper device with a pipe having an enlargement thereon passing through the device;

Fig. 4 is a view generally similar to Fig. 3 showing the stripper device contracted under well pressure to engage a pipe enlargement and prevent its withdrawal through the device;

Fig. 5 is a cross-sectional view taken generally along line 5-5 of Fig. 4; and

Fig. 6 is a fragmentary sectional view showing an arrangement employing a pair of the stripper devices employed for withdrawing a pipe under pressure.

Referring first to Fig. 2, the stripper and seal device in accordance with this invention, designated generally by the numeral 10, is shown mounted in a generally tubular Well head fitting, designated generally by the numeral 11,

2,762,638 Patented Sept. 11, 1956 which may be a generally conventional casing head on tubing head. For the purposes of this description and by way of illustration, fitting 11 is illustrated as a casing head, shown mounted in the usual manner on top of a conventional well head 12 which is connected to the upper end of the usual relatively large diameter surface pipe 13 which extends into a well bore (not shown).

As illustrated, casing head 11 comprises a generally tubular body 14 provided at its upper and lower ends with the usual radially projecting annular bolt flanges 15 and 16, respectively. The latter is removably connected to a mating flange 17 on well head 12 by means of bolts 18 and a conventional metal ring gasket 19 is installed between the adjacent faces of flanges 16 and 17 inwardly of the bolt circle to form a fluid-tight seal between the flanges. It will be understood that in accordance with common practice, casing head 11 may be mounted directly on the upper end of surface pipe 13, if desired. Body 14 is provided with a large central bore 20 which is coaxial with the bores of well head 12 and pipe 13 and is usually of substantially the same diameter. Bore 20 may be counter-bored from its upper end as at 20a or may be otherwise constructed to provide an upwardly facing internal shoulder 21 which is preferably tapered, as shown, for purposes to be more fully described hereinafter. Body 14 may be provided adjacent its lower end with one or more internally threaded ports 22 to which are connected pipes 23 for conducting fluids to or from bore 20.

It will be understood that casing head 14 may be a portion of an assembly of well head fittings, commonly referred to as a Christmas tree, and the upper end of casing head 14 may thus be connected to a series of superposed fittings, such as blow-out preventers, flow control valves, and the like, the lower end of such a fitting 24 being s'hown bolted to upper flange 15. In some cases the device of this invention may be employed with casing head 14 without having other fittings mounted thereon.

I A casing 25, made up in the usual manner of a plurality of end-threaded sections 25a-25a connected endto-end by means of screw collars 26 is shown extending through the bore 20 and in process of being drawn through the casing head from the well. The collars 26 necessarily form external enlargements on casing 25, the ends of the collars forming annular upper and lower external shoulders 27 and 28, respectively.

Stripper and seal device 10, as best seen in Fig. 1, comprises a generally tubular sealing sleeve, designated generally by the numeral 30, a frusto-conical, segmented metallic reinforcing core member, designated generally by the numeral 31, insertible in sleeve 30, the sleeve and core being dependently supported from a body or bowl member, designated generally by the numeral 32, having a hanger collar, designated generally by the numeral 33, threadedly connected thereto.

Sealing sleeve 30 comprises a unitary body composed of an upper frusto-conical section 34 merging with a straight tubular skirt portion 35, having a central bore 36 dimensioned to snugly engage the exterior of a pipe, such as casing 25, which is to be drawn thereto. Skirt portion 35 by its inherent flexibility, will stretch sulficiently to allow enlargements such as collar 26, to pass through bore 36 and will thereafter contract to again engage the exterior of the pipe. The lower end of skirt portion 35 is upwardly and inwardly tapered at 37 to guide enlargements such as collar 26 into the interior of the sleeve. The upper end of frusto-conical portion 34 is formed with an external depending lip portion 38 adapted for purposes to be subsequently described. The upper inner edge of portion 34 may be rounded or chamfered, as at 39.

Core member 31 is frusto-conical in shape adapted to contract with portion 34 during operations to be described The upper end of each of segments 40 is hereinafter; provided with a radially outwardly ofi set head portion 41 provided with an inwardly turned lip 42. somewhat shorter than the width of the off-set of head portion 41. The lower ends of segments 40 are formed to have upwardly and inwardly tapered guiding surfaces 43..

Body or bowl member 32 comprises a generally tubular metallic body 44, having formed at its lower end an outwardly extending annular lip 45 which is adapted to engage beneath lip 42 on core member 31 to provide a hinge connection thereto whereby the segments of core member 31 may pivot or rock about the lower end of body 44 while being dependingly supported thereby. The engaging surfaces of lips 42 and 45 may be suitably rounded, asshown, so as to aid the swinging movement of segments 40 about lip 45. Body 44 has a central bore 46 coaxial with bores 31a and 36 and somewhat larger in diameter than the smallest diameters of either of these bores. The wall of'bore' 46 may be provided with a downwardly and inwardly tapered frusto-conical surface 47. The exterior of body 44 is provided with an upper larger diameter portion 48 and a lower portion 49' of reduced diameter relative to portion 48 to provide a downwardly facing external shoulder 50 intermediate the ends of body 44. The exterior of lower portion 49 is provided with external threads 51 adjacent its lower end' and aseal ring 52 is circumferentially seated in the exterior surface of portion 49 above threads 51. The upper end of body 44 may be provided on its outer edge with a tapered or chamfered surface 53.

Hanger collar 33 comprises a tubular body 54 provided at its upper end portion with internal threads 55 adapted to engage threadsSl of body 44 for removably attaching collar 33 to body 44. Collar body 54 is of a length to extend well below the lower end of body 44 when secured thereto and is provided at its lower end with an inwardly and upwardly projecting lip 56 adapted to be engaged beneath lip 38 of sealing sleeve 30.

The elements composing stripper and seal device may be assembled in a convenient manner into a unitary structure; This may be accomplished by hanging the segments of'the core member 31 on lip 45 of bowl member 32, slidingsealing sleeve 30 over the exterior of core 31, then sliding hanger collar 33 over sleeve 30 to engage lip 56 with lip 38 on the seal member, and then screwing the upper end of collar 33 over the lower end of body 44 of the bowl member.

The unitary structure may then be inserted into bore 29' of casing head 11, as may best be seen in Fig. 2. Before inserting the stripping and seal structure in the casing head, a metal compression ring 57 and a superposed flexible packing ring 53 will first be installed about reduced portion 49 of bowl member 32 below shoulder 50, compression ring 57 being adapted to seat onshoulder 21' and provided with a tapered end surface 59 which is generally complementary to the taper of shoulder 21. Packing ring 58 may thereupon be compressed between compression ring 57 and shoulder 50 to seal the annular space between the interior of reduced portion 49 and the wall of'counter-bore 26a. It will be seen that shoulder 21 coacts with shoulder 50 through the medium of compression ring 57 and packing ring 58 to limit the extent of inward movement of the stripper and seal device 10 in the bore of easing head 11, although the resilience of packing ring 58 will-"permit a sufficient degree of such movement in order to provide effective sealing between the device and the casing head.

Compression of packing ring 58 may be accomplished in any suitable manner. One means which may be employed for this purpose is illustrated in Fig. 2 and includes a segmental metal hold-down ring 60 which is seated in an annular groove 61 provided in the wall of counter-bore 20a at a point which will be adjacent the upper end of body 44 when the latter has been fully inserted in the casing head. Ring 60 is provided on its lower inner edge with a charnfered surface 62 adapted to engage tapered surface 53 on the upper end of body 44 when ring 60 is projected from groove 61. Ring 60 is provided at a plurality of angularly spaced points with internally threaded sockets 63, one shown, into each of which is extended the threaded end 64 of a drive screw 65 which is rotatably journalled. in a radial passage 66 provided in flange 15 and registering with socket 63. Passage 66 is provided with an internal shoulder 67 against which is seated an annular shoulder or flange 68 mounted or formed on screw 65. A bushing 69 is screwed into the outer end of passage 66 and surrounds screw 65 and a seal ring 70 is mounted about screw 65 between flange 68 and bushing 69 to be compressed thereby to form a seal about the screw. The outer end of screw 65 which projects exteriorly of flange 15 is provided with a squared or polygonal end 71 for application of a wrench or other tool' for turning screw 65. By turning screws 65' in one direction, the segments of' hold-down ring 60 may be urged inwardly, the tapered surface 62 engaging surface 53 on the upper end of body 44 and forcing thev over the upper end of casing 25 for use both in running.

the casing into the well or when withdrawing it from the well. In any case, with the stripper and seal device installed about the casing, as illustrated in Fig. 2, the.

casing may be drawn through the device while the device maintains a safe and eifective seal between the casing and casing head under all conditions.

It will be assumed that the casing is being withdrawn under conditions when little or no pressure exists in the annular space between the casing and the casing head below the stripper device. Under these conditionssealing sleeve 30' will maintain close fitting wiping engagement with the exterior of the casing and will be expanded by the expansive'thrustof enlargements, such as collar 26, to allow the latter to pass readily through the sleeve. Core 31 will likewise be expanded by the enlargements to permit their passage through the device. The positions of the several parts immediately prior to the entry of collar'26 into the lower end of sleeve 30 isillustrated in Fig. 2, while Fig. 3 illustrates the positions of the same parts'when collar 26 has progressed partly through the device.

If, during the withdrawal of the casing, pressure should suddenly develop in the annular space below the stripper device, which is substantially in excess of any pressure in the space above the stripper device, this excess pres-- sure will be exerted against the relatively large area con stituting the exterior surface of sealing sleeve 30 and willurge the latter radially inwardly about the casing. This inward force will also be transmitted through upper portion 34 of the sleeve against segments 40 constituting core 31' and will urge these segmentsinwardly to their a substantially continuous metallic reinforcement for upper portion 34 which will effectively prevent extrusion of the resilient material constituting sleeve 30 through the annular space between casing 25 and the casing head. The pressure exerted against lower tubular skirt portion 35 will compress this portion tightly about collar 26 and thereby effectively prevent the leakage of pressure between these parts. It will be seen, therefore, that should a sudden increase of pressure occur in the well about the exterior of the casing so as to tend to cause a blowout While the casing is being withdrawn, the stripper and seal device will be automatically actuated to prevent further withdrawal of the casing and to provide a fluidtight seal about the casing, the tightness of which will be increased as the pressure is increased.

When the pressure has been relieved, as by pumping hydraulic fluid into the annular space through connection 23, or by releasing the pressure through the latter, if the pressure surge happens to be temporary, the withdrawal of the casing may be continued until the operation is completed.

The device may also be used for running casing 25 into the well and will maintain control of the well against blow-outs. Should a sudden increase of pressure occur, the casing, if not itself blown upwardly by the pressure, may be drawn upwardly until a collar or other enlargement thereon is brought up against the lower end of core 31 which will stop further upward movement of the casing and seal the annular space as described, thereby holding the well under control under the pressure condition has been overcome in any of the ways well known in the art.

If desired, bowl 32 may be employed as a slip bowl for casing or tubing hangers, the sloping surface 47 serving as a wedging surface for slips 72, shown in broken lines in Fig. 2, which may be inserted in the bowl about the pipe, such as casing 25, to support the latter in the Well bore in the generally conventional manner.

Fig. 6 illustrates another arrangement whereby two of the stripper and seal devices may be employed to Withdraw pipe from a well while under pressure.

In this arrangement an elongated tubular Well head 75 is employed through which a pipe 76, having collars 77 connecting the sections thereof, is to be drawn. Two of the stripper and seal devices a and 10b are mounted in longitudinally spaced relation in Well head 75, lower device 10a being seated on an internal shoulder 78 in the lower portion of head 75. 'Upper device 10b is supported in longitudinally spaced position above device 10a by an elongated spacer sleeve 79 positioned adjacent the inner wall of head 75. A fluid passage 80 extends through the wall of head 75 below device 10a and communicates with the annular space between head 75 and pipe 76 below device 10a. A pipe 81 is connected to the outer end of passage 80. A similar fluid passage 82 extends through the wall of head 75 and spacer sleeve 79 at a point intermediate devices 10a and 10b and communicates with the annular space between sleeve 79 and pipe 76 intermediate devices 10a and 10b. A pipe 83 is connected to the outer end of passage 82.

A pipe manifold, indicated generally by the numeral 84, includes a header 85 having branch pipes 86 and 87 connected to pipes 81 and 83, respectively. Additional branch pipes 88 and 89 fitted with valves 90 and 91, respectively, are connected to header 85 and a valve 92 is installed in header 85 between branch pipes 88 and 89.

With pressure existing in the annular space below device 10a, as pipe 76 is drawn upwardly, collar 77 will lodge against core 31a of this device in the manner previously described and further upward movement of the pipe thus prevented. To allow further upward movement of the pipe, the pressure above and below device 10a may be equalized by opening valve 92 and allowing pressure from below device 10a to flow into the head between devices 10a and 10b} When the pressure has been thus equalized, the parts of device 10a will be free to expand and pipe 75 may be drawn upwardly therethrough until collar 77 strikes core 31b of device 10b, as indicated by the broken lines in Fig. 6. Core 31b will be in contracted position by reason of the pressure below device 10b now having become greater than that above device 10b which will usually be substantially atmospheric. Valve 92 will now be closed and valve opened to the atmosphere to vent the pressure from between devices 10:: and 10b, thus providing balanced atmospheric pressures above and below device 10b, whereby the pipe carrying collar 77 may now be drawn upwardly through device 101). At the same time the high pressure will be confined below device 10a and will serve to engage the next collar on pipe 76 whereupon the described operations may be repeated to permit further upward movement of the pipe. This sequence of operations may be repeated as long as required to withdraw the pipe from the well.

Pressure fluid to equalize the pressure across device 10a may, if desired, be introduced from an extraneous source through branch pipe 88, valve 92 being closed. Hydrostatic fluid, such as weighted mud, may be introduced through branch pipe 89, valve 92 being closed, into the annular space below device 10a, if desired to prevent the entrance of well gas into the annular space below device 10a in order to thus relieve the pressure on device 10a.

From the foregoing it will be evident that the stripper and seal device in accordance with the present invention provides a simple and effective means for assuring complete control of a well during the pulling of pipe strings therefrom. It will be understood that numerous modifications and changes may be made in the illustrative embodiments within the scope of the appended claims without departing from the spirit of this invention.

What I claim and desire to secure by Letters Patent is: y 1. In combination with a generally tubular well head fitting and a pipe movable axially through the bore thereof, a stripper and seal device for sealing said bore between the fitting and the pipe, comprising, a generally tubular body insertible in said bore about said pipe, a collar member separably secured about the exterior of said body and having at its lower end an inwardly projecting annular lip spaced below the lower end of said body, a resilient sealing sleeve comprising a downwardly tapering frusto-conical .upper portion and an axially straight tubular lower portion adapted to sealingly engage the exterior of said pipe, the upper portion of said sealing sleeve having an outwardly projecting annular lip engageable with said inwardly projecting lip on said collar member whereby to dependingly support said sealing sleeve from said body, a frusto-conical metallic core member comprising complementary arcuate segments removably seated in said upper portion of said sealing sleeve, hinge means hingedly connecting the upper ends of said segments to said body whereby to permit radial contraction and expansion of the core member relative to the pipe in response to contraction and expansion of said sealing sleeve, and sealing means circumferentially disposed in sealing engagement between said body and the bore wall of said fitting above said sealing sleeve.

2. A stripper and seal device according to claim 1, wherein said hinge means comprises, an inwardly directed lip member formed on the upper end of each of said segments, and a complementary outwardly directed annular lip member on the lower end of said body extending beneath the lip members on said segments.

3. A stripper and seal device according to claim 1 having annular sealing means disposed between said shoulder means and compressible therebetween to seal between the exterior of said body and the adjacent wall of said bore.

4. In a stripper and seal device according to claim 1, hold-down means retractably mounted in said fitting and 7 extendible into engagement with the upper end of said body to limit upward movement of said body in said fitting.

In combination with a generally tubular well head fitting and a pipe movable axially through the bore there of, a stripper and seal device for sealing said bore between the fitting and the pipe, comprising, a generally tubular body insertible in said bore about said pipe, a collar member separably secured about the exterior of said body and having at its lower end an inwardly projecting annular lip spaced below the lower end of said body, a resilient sealing sleeve comprising a downwardly tapering frusto-conical upper portion and an axially straight tubular lower portion adapted to sealingly engage the exterior of said pipe, the upper'portion of said sealing sleeve having an outwardly projecting annular lip engageable with said inwardly projecting lip on said collar member whereby to dependingly support said sealing sleeve from said body, and a frusto-conical metallic core member comprising complementary arcuate segments removably seated in said upper portion of said sealing sleeve, and hinge means hingedly connecting the upper ends of said segments to said body whereby to permit radial contraction and expansion of the core member relative to the pipe in response to contraction and expansion of said sealing sleeve, said hinge means comprising an inwardly directed lip member formed on the upper ends of said segments, and a complementary outwardly direct-ed annular lip member on the lower end of said body extending beneath the lip members on said segments.

6. In combination with a generally tubular well head fitting having internal shoulder means in the bore thereof and a pipe movable axially through said bore, a stripper and seal device for sealing said bore between the fitting and the pipe, comprising, a generally tubular body insertible in said bore about said pipe, external shoulder means on saidbody seatable on said shoulder means in said bore to limit downward movement of said body in said bore, a collar member separably secured about the exterior of said body and having at its lower end an inwardly projecting annular lip spaced below the lower end of said body, a resilient sealing sleeve comprising a downwardly tapering frusto-conical upper portion and an axially straight tubular lower portion adapted to sealingly engage the exterior of said pipe, the upper portion of said sealing sleeve having an outwardly projecting annular lip engageable with said inwardly projecting lip on said collar member whereby to dependingly support said scaling sleeve from said body, a frusto-conical metallic core member comprising complementary arcuate segments removably seated in said upper portion of said sealing sleeve, and hinge means hingedly connecting the upper ends of said segments to said body to permit radial contraction and expansion of said core member relative 8 to said pipe in response to contraction and expansion of said fsealingjsl'e'eve, said segments when in radially contracted pes'ition' being adapted to form a substantially continuous annular abutment inside the bore of said sleeve amnesty engageable with an external enlargement on said pipe.

7. In eoi'nbination with a generally tubular well head fitting and a pipe movable axially through the bore thereof, a stripper and seal device for sealing said bore between-the fittingf and the pipe, comprising, a'pair of longitudinally spaced generally tubular seal members and a tubular spacer sleeve interposed between said seal members -to for'm therewith an elongate tubular structure removably insertible in said bore about said pipe, said spacer sleeve having a passageway through the wall thereofto provide communication between the exterior and interior of said structure at 'a point intermediate said seal members, each of said seal members comprising a generally tubular body i'ns'er'tible in said bore about said pipe, a collar member separably secured about the exterior of said body and having at its lower end an inward- 1y projecting annular lip spaced below the lower end of said body, a resilient sealing sleeve comprising a downwardly tapering frusto c'onical upper portion and an axially straight elongate tubular lower portion adapted to sealing'ly engage the exterior of said pipe, the upper portiondf said sealing sleeve having an outwardly projecting annular lip engageable with said inwardly projecting lip on said collar member whereby to dependingly support said sealing sleeve from said body, and a frusto-conical metallic core member comprising complementary arcuate segments removably seated in said upper portion of the sealing sleeve, and hinge means hingedly connecting the upper ends of said segments to said body to permit radial contraction and expansion of said core member relative to said pipe in response to contraction and expansion of said sealing sleeve, said hinged means comprising an inwardly directed lip member formed on the upper ends of said segments, and a complementary outwardly directed annular lip member on the lower' end of said body extending beneath the lip members on said segments.

References Cited in the file of this patent UNITED STATES PATENTS 1,583,562 Stenner May 4, 1926 1,586,923 Townsend June 1, 1926 1,811,013 I Iumason June 23, 1931 1,902,906 Seamark Mar. 28, 1933 2,035,925 Seamark Mar. 31, 1936 2,284,869 Hinderliter June 2, 1942 2,287,205 Stone June 23, 1942 2,529,744 Schweitzer Nov. 14, 1950 2,583,497 Schweitzer Ian. 22, 1952 2,610,869 Eckel Sept. 16, 1952

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