US3437356A

US3437356A - Casing hanger and seal assembly

Info

Publication number: US3437356A
Application number: US635089A
Authority: US
Inventors: William L Todd; Bobby L Ferguson
Original assignee: RECTOR WELL EQUIPMENT CO Inc
Current assignee: RECTOR WELL EQUIPMENT CO Inc
Priority date: 1967-05-01
Filing date: 1967-05-01
Publication date: 1969-04-08
Anticipated expiration: 1986-04-08

Description

April 8, 1969 w. L. TODD ET AL 3 CASING HANGER AND SFAL ASSEMBLY Filed May 1, 1967 I Sheet of 4 29 INVENTORS 52 0 W/'///'amL.T0a'd ,4/ 28 Bobby L. Ferguson l BY M A ATTORNEY April 8, 1969 w, TODD ET AL 3,437,356

CASING HANGER AND SEAL ASSEMBLY Filed May 1, 1967 Sheet 2 of4' III INVENTORS Wil/iam Lloda Bobby L. Ferguson ATTORNEY April 8, 1969 v w, TODD ET AL 3,437,356

CASING HANGER AND SEAL ASSEMBLY INVENTORS Will/am L. Toa'o' Bobby L. Ferguson ATTORNEY April 8, 1969 w, T D ET AL CASING HANGER AND SEAL ASSEMBLY Filed May 1, 1967 INVENTORS Will/am 7'000' Bobby L Ferguson ATTORNEY United States Patent 3,437,356 CASING HANGER AND SEAL ASSEMBLY William L. Todd and Bobby L. Ferguson, Fort Worth, Tex., assignors to Rector Well Equipment Company,

Inc., Fort Worth, Tex., a corporation of Texas Filed May 1, 1967, Ser. No. 635,089

Int. Cl. F16] 35/00, 25/00; E21b 19/02 U.S. Cl. 285-3 11 Claims ABSTRACT OF THE DISCLOSURE A casing hanger and seal assembly for suspending casing in a well which includes segmented slips carried in a separable bowl. The bowl is retained in assembled relationship about the slips by means of a latch ring which encircles the bowl.

A casing hanger and seal assembly for suspending casing in a well which includes segmented slips carried in a separable bowl wherein the slips are slidably suspended to the bowl. The bowl is retained in closed position about the slips by a latch ring which is positioned in an annular recess formed about the outer surface of the bowl segments. The latch ring is quickly and easily engageable about the assembly and when engaged the outer surface thereof conforms to the outer surface of the bowl segments.

Joinder pins extend through aligned passages in the latch ring and the bowl and are threadedly engaged to the Slip segments. The passages are of such size as to permit the slip segments to move vertically with relation to the bowl and the latch ring. Thereby the bowl and slips may be suspended together in predetermined vertical relationship, and are held together with the co-acting surfaces in engagement, by the latch ring in order to hold same in predetermined relationship while being seated in the bore of a casing head, yet permits the slip segments to move vertically with relationship to the bowl after the bowl is seated in the casing head when the weight of pipe is exerted against the inner teeth on the slips.

In an alternate form of the invention an automatic seal assembly is suspended below the bowl segments, and the lower ring of the automatic seal is arranged to seat on an annular shoulder in the casing head bore. The seal assembly is attached to the bowl segments by screws which slidably extend through the seal assembly and are threadedly engaged to the bowl segments so that the bowl segments are permitted to move vertically to automatically compress the seal by downward movement of the slips upon engagement with the casing.

In suspending casing on slip segments suspended in a bowl seated in the bore of the casing head it is desirable that the slips be maintained in a predetermined annular relationship with the bowl and at the same time the slips must be suspended to the bowl in such a way that they can move vertically with relation to the bowl upon setting. Furthermore, it is desirable that the bowl be made in separable segments so that the assembly can be placed about the pipe before lowering into the casing head bore. It is also desirable that the bowl be permitted to move vertically with relation to the slips so that movement of the bowl vertically can compress and seal an automatic seal within the casing head bore.

The invention disclosed and claimed herein answers all of the foregoing requirements.

It is, therefore, a primary object of the invention to provide means for slidably suspending slip segments in a separable bowl which retains the slips and bowl in predetermined assembled relationship both annularly and vertically as the assembly is being transported, and lowered and seated in the casing head bore.

3,437,356 Patented Apr. 8, 1969 A further object of the invention is to provide a slidable connection between slip segments and a bowl which prevents rotatable movement with relation to each other but permits relative vertical movement therebetween.

Still another object of the invention is to provide a disengageable latch ring extending about a bowl in which slips are suspended which limits expansion of the bowl segments, yet permits relative vertical movement between the bowl and the slips.

A still further object of the invention is to provide a vertically slidable connection between slip segments and the segments of a bowl in which they are carried which prevents relative rotational movement between the slip segments and the bowl, but on the other hand permits the slips to move vertically with relation to the bowl, which retains the slip segments in engaged position about the bowl and which permits the bowl segments to move vertically with relation to the slip segments to expand an automatic seal suspended below the bowl segments, and seated in the casing head bore.

Other and further objects of the invention will become apparent upon reading the detailed specification hereinafter following and by referring to the drawings annexed hereto.

Suitable embodiments of the invention are shown in the attached drawings, wherein:

FIGURE I is a vertical cross-sectional elevational view of a casing head assembly with pipes suspended therein, employing the novel slip suspension assembly disclosed and claimed herein;

FIGURE II is a transverse sectional view taken along the line IIII of FIGURE I;

FIGURE III is a cross-sectional elevational view of the slip suspension assembly as it would appear in unseated position prior to being lowered into the casing head wherein the bowl and the slips are secured together by a temporary withdrawable screw;

FIGURE IV is a cross-sectional elevational view of a modified form of the pipe suspension assembly as it would appear in seated position in a casing head bore suspending a pipe therein, and wherein an automatic seal assembly is employed therewith;

FIGURE V is a fragmentary cross-sectional elevational view showing a modified upper seal assembly disposed about the upper end of the casing string;

FIGURE VI is a top plan view, partially sectionalized, of the latch ring employed with the pipe extension assembly;

FIGURE VII is a side elevational view of the latch ring;

FIGURE VIII is a side elevational view of the tongue end of the latch ring as it would appear in disengaged position;

FIGURE IX is a sectional view taken along the line IX-IX of FIGURE VIII;

FIGURE X is a side elevational view of the recessed end of the latch ring which receives the latched tongue shown in FIGURE VIII;

FIGURE X1 is a sectional view taken along the line XIXI of FIGURE X;

FIGURE XII is a side perspective view of the joined ends of the latch ring, showing the tongue and inserted in the recess of the recessed end; and

FIGURE XIII is a fragmentary side elevational view of a modified form of latch which may be employed with the latch ring.

Numeral references are employed to indicate the various parts shown in the drawings and like numerals indi cate like parts throughout the various figures of the drawings.

Referring first to the form shown in FIGURE I, the numeral 1 indicates a casing head having a bore 2 therein.

3 An annular tapered seat 3 is provided in the lower end of the bore.

Circulation conduits 4 and 5 communicate through passages in the wall of the casing head bore for the purpose of providing fluid flow or circulation with the annular space between the casing C and the surface casing 6. The surface casing 6 is customarily cemented in the well bore, and is connected to the casing head 1 by suitable threads 7.

An annular flange 8 is provided about the upper end of the casing head 1 and has bolt receiving passages 8a therethrough.

A seal flange 9 may be mounted above the casing head 1, and has an annular flange 10 coinciding with the flange 8. The annular flange 10 has bolt receiving passages 10a therethrough and spaced thereabout which are arranged to coincide with the bolt receiving passages 8a.

Bolts 11 extend through coinciding passages 8a and 10a and are brought together in sealed relationship by nuts 11a threaded thereon.

A metal seal ring 12 is positioned in the bore 2 and suspended therein on a split ring 12a which is disposed in a suitable annular groove 12b provided about the bore 2.

The seal ring 12 may be welded in sealed relationship about the upper end of the casing string C by weld material 13 disposed in a suitable groove 13a provided about the upper inner side of the ring 12.

A seal is provided between the

flanges

10 and 8 and the ring 12 by means of a deformable metal seal ring 14 which may be inserted in suitable opposed grooves 14a and 14b formed in the lower surface of the flange 10 and between the ring 12 and the inner surface of the flange 8.

A seal ring 15, which is made of elastic material such as rubber or plastic composition is disposed between rigid upper and lower back-up rings 16 and 17.

Coinciding opposed shoulders, indicated at 18 are provided within the bore of the seal flange 9 and on the outer side of the upper back-up ring 16, and the lower back-up ring 17 is arranged to seat against the upper surface of the metallic seal ring 12. It will be seen that as the seal flange 9 is drawn downwardly toward the upper surface of the casing head the resilient seal ring will be compressed and sealed between the inner surface of the seal flange 9 and the outer surface of the casing C, and the seal ring 14 will be compressed to provide a seal between the

flanges

8 and 10.

A plurality of slip segments 19 have upwardly directed teeth 190: on the inner surfaces thereof arranged to engage the outer surface of the casing to move same downwardly and anchor same into biting engagement with the casing.

The slip segments 19 may be jointed together by pins 20 which are fixed at one end to the edges of the slip segments and the free ends thereof slidably extend into enlarged bores 20a provided in the sides of adjoining slip segments. Thereby the slip segments are engaged against relative vertical movement but are permitted to expand and contract as they move inwardly and outwardly.

The slip segments 19 are seated in a bowl which is comprised of

segments

21 and 22 and which may be disengageably attached against relative vertical movement by

tongue connections

23 and 24. The slip segments 19 and

bowl segments

21 and 22 have coinciding tapered surfaces, indicated at 21b, so that upon relative vertical movement between the slip segments and the bowl the slip segments 19 will be caused to move inwardly toward the casing C. The

bowl segments

21 and 22 have passages 25 therethrough, such passage being arranged to coincide with threaded passages 26 in the slip segments 19.

Temporary retaining screws 27 (FIGURE III) may be inserted through the passages 25 and threadedly engaged in the threaded passages 26 to retain the segments 19 in connected relationship with the bowl segments 25 while the assembly is being transported and while it is being positioned about the casing C and latched thereabout, preparatory to lowering same into the casing head bore 2 in the manner hereinafter described.

A retaining band or ring 28 has elongated or enlarged passages 29 therethrough and spaced thereabout. A shoulder 30 is provided about the elongated passages 29 through which guide screws 31 may be extended, and the heads 33 are arranged to contact the shoulders 30 to limit outward movement of the latch band 28 relative to the slip bodies 19, yet permits relative vertical movement between the

bowl segments

21 and 22 and the slip segments 19. The screws 31 have threaded ends 32 thereon which are threadedly engaged in threaded passages 32:: provided in each slip segment 19.

A groove 34 is provided on the outer surface of the latch band 28 opposite the disengageable connection therebetween to provide a flexible hinge to permit the band 28 to be bent at the weakened portion provided by the groove 34 so that the band 28 may be opened to pass same about the

bowl segments

21 and 22 and to provide a hinge for passing the bowl and slip assembly about a pipe as hereinafter described. The retaining band 28, as shown, is made of relatively hard rubber or other resilient material such as a plastic composition and may have a slight elasticity, although such function is not necessary. The band 28 could be made of any other material such as composition or metal and a hinge could be provided at the point 34 to permit same to be opened. Coinciding annular grooves 21a and 22a are provided in the outer surface of the

bowl segments

21 and 22 which, when the

bowl segments

21 and 22 are brought together in assembled relationship, provide a continuous groove thereabout. The grooves 21a and 22a are preferably conformed to the shape of the latch band 28 and are arranged to receive the latch band so that when the band 28 is disposed therein the outer surface of the band conforms to the outer surface of the

bowl segments

21 and 22. It will be noted that the inner surface of the grooves 21a and 22a are tapered in alignment with the coinciding tapered surfaces of the slips 19 and

bowl segments

21 and 22 so as to permit the axis of the guide pins 31 to be normal to the said coinciding tapered surfaces to permit slidable movement thereb etween.

The latch band 28 may be disengageably joined at the ends thereof by means of a latch tongue 38 insertable in a recess 35 provided in the opposite end of the latch band. The recess 35 has a tapered entry surface 35a therein, and a channel 36 extends through the end of the latch ring and communicates with the recess 35, providing shoulders 37 which engage the enlarged end of the tongue 38. The tongue 38 includes a reduced section 38a which fits in the channel 36 as the enlarged end 38!; thereof is inserted into the recess 35 and guided thereinto along the tapered entry surface 35a.

It will thus be seen that the ends of the retaining band 28 may be quickly fastened about the

bowl segments

21 and 22 to retain them in assembled position. Since the retaining band 28 is made of elastic material and has a slight elasticity it may be slightly stretched and expanded in securing it about the

bowl segments

21 and 22 and upon releasing same the elasticity thereof will cause the head 38b of the tongue 38 to be firmly pressed against the shoulders 37 to retain the band in engaged position about the bowl segments.

The operation and function of the device hereinbefore described is as follows:

The slip segments 19 are temporarily attached to the

bowl segments

21 and 22 by extending screws 27 through passages 25 and threading the ends thereof into threaded passages 26. The retaining band 28 is opened about the hinge 34 and positioned about the

bowl segments

21 and 22 in the grooves 21a and 22a and the guide screws 31 are passed through the passages 29 and threadedly engaged by threaded ends 32 in the threaded holes provided in the slip segments 19. The assembly may then be latched together by engaging the tongue 38 in the recess 35, and in such position it may be transported in assembled relationship. The temporary screws 27 hold the slips 19 and

bowl segments

21 and 22 in attached and assembled relationship and the retaining band 28 holds the

bowl segments

21 and 22 together.

When it is desired to install the assembly about a casing C Within a well bore 2 the tongue 38 may be disengaged from the recess 35 to permit the

bowl segments

21 and 22 to be opened by flexure of the hinge 34 for the retaining band 28. The entire assembly may be thus placed about the casing C extending upwardly through the bore of the casing head. The casing at this point is suspended at the well head by conventional temporary pipe suspending equipment. The slip and bowl assembly is latched about the casing C by engaging the tongue 38 with the recess 35, and the temporary retaining pins 27 is removed before lowering the assembly into the bore 2 about the casing C. The assembly is lowered into the bore 2 until the tapered shoulder about the lower side thereof contacts the tapered shoulder 3 in the bore 2 (FIGURE I). The casing is then released sufliciently to allow it to move downwardly against the upwardly facing teeth 19a to move the slip segments 19 downwardly. As the slip segments move downwardly the co-acting tapered surfaces 21a between the slip segments and the bowl segments cause the slips to move inwardly to permit the teeth 19a to penetrate the outer surface of the pipe C to anchor and support same while the well head assembly is being completed.

It will be noted that during this setting procedure the

bowl segments

21 and 22 are retained in engagement about the slip segments 19 by the retaining band 28 and that the retaining band maintains the bowl segments in spaced relationship to the wall of the casing head bore so that there is no frictional engagement between the bowl segments and the bore which could cause uneven movement of the slips 19 with relation to the bowl segments. It will further be noted that as the slip segments 19 move downward relative to the

bowl segments

21 and 22 the guide pins 31 move downward in the elongated holes 29 and prevent lateral or rotational movement of the slip segments 19 with relation to the bowl to assure uniform engagement of the slip segments with the pipe.

After the slips have been engaged in anchoring position with relation to the pipe C in the manner hereinbefore described the casing C may be cut off at the upper end and the weld ring 12 placed thereabout and seated on the ring 12a. It is then welded to the casing by the weld 13a. The seal assembly comprised of the resilient seal ring 15 and back-up rings 16 and 17 are placed about the upper end of the casing C. The seal flange 9 is placed over the seal assembly, the holes 8a and a in the

flanges

8 and 10 are aligned, the bolts 11 are placed therethrough and the nuts 11a are threaded thereon to draw the flanges together and compress the metal seal ring 14 and the resilient seal ring to provide a seal about the upper end of the casing string C. The well is then ready for completion by running tubing strings through the casing C and attaching the usual Christmas tree assembly.

In the modified form shown in FIGURE IV an automatic packoif is provided for sealing the annulus between the casing C and casing 6, which would be desirable where excessive pressures are involved within the well bore, and the automatic seal provides protection against such pressures when the blowout preventer is released for completing the well head assembly as hereinbefore described.

The automatic packoff includes a resilient seal ring 39 disposed between a rigid bottom back-up ring 40 and a rigid top back-up ring 41. Guide screws 42 freely extend through

passages

45, 46 and 47 through the

rings

40, 39 and 41, respectively. The screws 42 have threaded ends 42a which are threadedly engaged in threaded bores provided in the lower surfaces of the

bowl segments

21 and 22 and have heads 44 thereon disposed in counter bores 6 43 so that the heads 44 engage the shoulders provided by the counter bores 43 to retain the packoif assembly in assembled relationship.

The respective rings of the packofi" assembly are split as indicated at 40a, 39a and 41a in FIGURE IV so that they may be opened with the slip and bowl assembly for placing about the casing for lowering into the bore 2 in the manner hereinbefore described.

The lower back-up ring 40 has a tapered surface 40a on th lower end thereof which seats upon the correspond- IiJng tapered surface 3 in the lower end of the casing head ore 2.

When the casing string C is lowered against the teeth 19a on the slip segments 19 in the manner hereinbefore described the

bowl segments

21 and 22 are caused to move downwardly with the slip segments 19 to thereby move the guide screw 42 downwardly through the

passages

45, 46, and 47 provided through the

rings

40, 39 and 41, and since the back-up ring 40 is seated against the surface 3 the back-up ring 41 is pushed downwardly by the

bowl segments

21 and 22 to thereby compress and expand the resilient sealing ring 39 into sealing engagement with the casing C and the interior surface of the bore 2 to seal off the annulus between the casings C and 6 therebelow.

A modified top seal ring 48 is provided to close the upper end of the bore 2. Said modified metallic seal ring 48 has an O-ring seal 49 provided thereabout and the O-ring seal 50 provided about the inner side of the ring 48 is arranged to seal against the outer surface of the casing C. The seal ring 50 is disposed in a recess 51 provided interiorly of the ring 48 and is retained therein by a split ring 50a. Such a modified seal assembly may be employed with either form of the device herein disclosed.

In FIGURE V there is shown a modified upper seal assembly positioned in the bore of the seal flange 9 which includes a seal support ring 52 having spaced

annular recesses

54 and 55 therein in which are positioned resilient O-

ring seals

56 and 57. The O-

ring seals

56 and 57 are retained in the

respective channels

54 and 55 by

split rings

58, 59, and 60. The ring 52 is seated on an annular metal split ring 61 which is disposed in an appropriate groove about the inner side of the bore of the sealing flange 9.

In the modified form of FIGURE V the slip and bowl assembly is constructed, assembled, and set in the same manner as hereinbefore described and may or may not include the automatic seal assembly disclosed in FIG- URE IV.

FIGURE XIII shows a modified form of latch band or ring indicated generally at 62. The ring 62 may be made of slightly elastic material such as material of which ring 28 is made, or it may be made of rigid material, such as metal. The latch tongue 63 is hingedly attached in channel by a hinge pin 64. The hinge pin 64 may be slightly flexible to permit the head to be forced into recess 67 to cause same to be retained therein by frictional engagement with shoulders 68 and 69.

It will thus be seen that we have provided a slip and bowl assembly for suspending pipe in a well head wherein the assembly may be maintained as a unit in predetermined assembled relationship while being tranported, which may be opened as a unit for placing about the pipe and lowering into the well head bore and disengageably latched there-about, wherein the slips are permitted to move vertically with relationship to the bowl but are restrained against rotational movement with relation thereto, and wherein the bowl is retained and urged into engagement with the well head bore so as to assure uniform engagement of the slips with the casing. Alternate upper seal assemblies may be employed with such an assembly and same may incorporate an automatically set ting seal therebelow which is automatically set when the pipe is lowered against the teeth on the slips.

Having described our invention we claim:

1. In a pipe suspending assembly arranged to be seated in a well head bore about a pipe extending therethrough, a bowl comprised of separable segments, having radially extending inner and outer surfaces, arranged to be seated on a shoulder in the well head bore; a plurality of slip segments seated in the bowl on said inner surfaces, there being coinciding tapered surfaces between the slips and the bowl; a retaining ring extending circumferentially about the entire bowl, said retaining ring and bowl segments being all so constructed and arranged that said retaining ring retains said bowl segments in assembled relationship, said ring having hinge means at one side and free ends with latch means thereon for disengageably attaching the ring about the bowl; said retaining ring, hinge means, free ends and latch means all lying radially inwardly of the said outer surface, and co-engaging guide means between the slips and the bowl limiting relative rotational movement between the slips and the bowl, but permitting relative vertical movement therebetween.

2. The combination called for in claim 1 with the addition of means for temporarily securing the slips and the bowl together against relative movement.

3. The combination called for in claim 1 with the ad dition of seal means suspended to the bowl and being arranged to seat on the shoulder in the well head bore, said seal means being compressible into sealing engagement between the well head bore and the pipe upon downward movement of the bowl.

4. The combination called for in claim 1 wherein the retaining ring is recessed in a groove about the outer surface of the bowl.

5. The combination called for in claim 1 wherein the guide means comprises elongated vertically extending coinciding slots through the retaining ring and the bowl; guide screws extending through said slots and being threadedly secured to the slips; shoulder means about the edges of the slots; and heads on the screws engageable with the shoulder means to retain the members in assembled relationship.

6. The combination called for in claim 1 wherein the latch means between the ends of the retaining ring comprises a tongue on one end of the band and a recess on the other end of the band in which the tongue is disengageably latched.

7. The combination called for in claim 6 wherein the tongue is hingedly atached to the ring.

8. The combination called for in claim 3 wherein the seal means includes a resilient seal ring; a lower back-up ring; an upper back-up ring; coinciding passages through the rings; guide pins slidably extending through the passages through the rings and being threadedly attached to the lower surface of the bowl; and counter bores in the lower backup ring aligned with the said passages, the shoulders in said counter bores being suspended on the heads of the guide pins.

9. The combination called for i claim 1 wherein the ring is a fiat band.

10. The combination called for in claim 1 wherein the retaining ring is made of flexible material and the hinge is a groove in the surface of the ring which permits the ring to be bent at such groove.

11. The combination called for in claim 1 with the addition of a recess about the well head bore above the seal assembly; a split ring positionable in the recess and extending outwardly into the bore; and a seal ring seated on the split ring.

References Cited UNITED STATES PATENTS 144,997 11/1873 Mayall 285365 X 2,432,592 12/1947 Stecher et a1 285179 X 2,532,662 12/1950 Eckel et al 285-147 2,709,094 5/1955 Polanski 285--407 2,712,455 7/1955 Neilon 285144 2,824,757 2/1958 Rhodes 28l47 X 3,305,249 2/1967 Zahuranec 285-379 X 3,334,923 8/1967 Putch 285-147 X CARL W. TOMLIN, Primary Examiner.

DAVE W. AROLA, Assistant Examiner.

[1.3. Ci. X.R.