US2568581A

US2568581A - Casing hanger assembly

Info

Publication number: US2568581A
Application number: US96942A
Authority: US
Inventors: Robert L Crain
Original assignee: Gray Tool Co
Current assignee: Vetco Gray LLC
Priority date: 1949-06-03
Filing date: 1949-06-03
Publication date: 1951-09-18
Anticipated expiration: 1968-09-18

Description

Sept. 18, 1951 2,568,581

R. L. GRAIN CASING HANGER ASSEMBLY Filed June 5, 1949 2 Sheets-Sheet 1 ATTO R N EYS Sept. 18, 1951 R. I CRAIN CASING HANGER ASSEMBLY ZSheets-Sheet 2 Filed June 5, 1949 Patented Sept. 18, 1951 2,568,581 osrNc HANGER ASSEMBLY Robert L. Crain, Houston, Tex., assignor to Gray Tool Company, Houston, Tex., a corporation of Texas Application .l une 3, 1949, Serial No. 96,942

13 Claims.

The present invention relates to an oil well casing head and hanger assembly of the type which may be employed to permit the running and landing of successive strings of casing while maintaining' effective control of the well. The principal object of the invention is to provide a novel hanger and associated casing head assembly which will provide a permanent seal between the hanger and the casing head in which it is suspended and between the hanger and the casing which it suspends without the necessity of welding or using casing rolling practices as have been suggested and practiced. Ancillary to the object just mentioned, the invention is intended to provide such an assembly in which it is unnecessary to rely on temporary seals whose life is oi short duration to provide ccntrol throughout the life of the well.

In order to accomplish the above, I have provided a novel form of casing hanger which has means to form a permanent seal in the casing head in which it is landed, said hanger being formed in two parts providing an adjustable packing chamber which is closed except on its inner side which is open toward the casing being suspended, whereby, upon adjustment of the two parts of the hanger toward one another, the packing in the chamber is positively compressed inwardly toward the casing to form an effective and permanent seal therewith. The assembly further provides means for positively closing the outer side of the packing chamber as mentioned above, and positive means for limiting the movement of the hanger sections toward one another, so that the exertion of excessive pressure against the wall of the casing is avoided, so that the possibility of collapsing the casing by this excessive inward pressure is eliminated.

The invention comprises a lower hanger section having means to engage and suspend the inner casing and which is of suchdiameter that it may be lowered through control equipment mounted on the outer casing head and landed in its seat to form a permanent seal therein, so that the control equipment may he removed. The hanger further comprises an upper section which is thereafter mounted on the casing and tightened against the lov-:er section to form a permanent seal in the space between the inner wall of the hanger and the exterior of thelcasing which it suspends.

rlwo forms of the invention are illustrated in the dawings, it being understood that the invention may be practiced with apparatus oi somewhat modified construction.

In the drawings:

Figure 1 is a side elevational view'of a well head assembly for carrying out the invention, partly in section;

Figure 2 is an enlarged half sectionalview, similar to Figure 1;

Figure 3 is a vertical sectional view through the well head, including the control equipment, illustrating the manner in which the equipment of the present` invention may be used while maintaining mechanicalcontrol of the well;

Figure 4 is avertical sectional view showing the condition of the equipmentin an intermediate stage of `installation after the control equipment is removed showing particularly the manner of mounting and securing the upper hanger bushing; and

Figure 5 is an elevational view, partlylin section, showing a modied construction.

It will be understood that the present invention is particularly concerned with that type of double tapered casing hanger which is described in Patent` No. 2,082,413, Mueller etal., June 1, 1937, which hanger is used in carrying out the methods of the patent to Mueller et al., No.

2,117,444, May 17, 1938. However, the hanger disclosed herein is of the slip suspension type, the general construction and use of which is described in detail in Patent No..2,207,469, Roye, July 9, 1940. However, in `the arrangement disclosed herein, a particular type of slip suspension is employed, including the use of a temporary seal` associated with the slip suspension, as disclosed in ar co-pending application of Mueller et al., Serial No. 680,334, led June 28, 1946.

Referring to Figure l, the outside well casing is shown at I' and mounted thereon isthe casing head of now well-known construction I2 having the -usual side outlet I4, taperedhanger seat Iii, and connectingange I8. The `inner casing is indicated by the numeral 2li, andthe hanger assembly is shown associated with a casing hanger and arranged'to suspend same inthe casing head i8 while providing mechanical control of the well.

The details of the hanger are better illustrated in Figure 2. The hangercomprises a lower bushing B1 and an upper bushing B2, said bushings having central bores therethrough, as shown, in order to closely embrace the inner casing 2D. The bore of the lower hanger bushing at its` lower end is only slightly greater than the exterior diameter of the casing, as indicated at 24. The central part of the lower hanger bushing is counterbored as at 2B to form a wider cylindrical chamber to receive the slip assembly consisting of the slip cage 28 and the slip segments 30, the precise construction of this slip arrangement being described in detail in the said co-pending application, Serial No. 680,334. Between the lower end of the chamber and the lower hanger bore 24, there is a short counter-bore chamber 32 of intermediate diameter. This chamber is of Vertical dimension sufficient to receive several packing rings capable of expansion outwardly and inwardly upon the application of vertical pressure thereto to form a seal between the inner wall of the lower hanger bushing and the outer wall of the casing.

The lower hanger bushing tapers upwardly and outwardly to conform with the taper of the seat in the casing head I2, and in this tapered portion of the hanger, there are a plurality of rings of packing extending entirely around the hanger which make a permanent seal with the casing head when the hanger is suspended therein.

It will be understood that the lower hanger bushing is of maximum exterior diameter slightly less than theminimum interior diameter of the control equipment which is customarily mounted on the casing head I2, so that this lower hanger bushing may be landed through this control equipment in the manner well-known in the art while maintaining mechanical control of the well, as is discussed in detail in the patents and in the application referred to above. That is, the hanger bushing is of such diameter that it will pass through the control equipment now well-known in the art which is of rated size with relationto the casing I5 to which the casing head I2 is connected, this control equipment being attached to the flange I8 of the casing head l2 as illustrated in Figure 3.

Above its tapered portion, the upper end of the lower hanger bushing is formed with a flatledge or shoulder 3E, an upwardly tapered annular portion 38 surmounted by a` short vertical cylindrical extension 40. The portion 40 terminates in a relatively sharp circular edge, formed by a downwardly tapered inside area 42 which forms the inside wall of the packing chamber referred to above and to be hereinafter described.

The upper hanger bushing has an outside tapered area 44 with packing rings therein, and it will be understood that this area is adapted to seal with the inside 46 of the casing head or tubing head 48 mounted above the hanger, whereby the area against which pressure from within the casing 20 may exert itself is substantially reduced.

The upper hanger bushing B2 has a bore of diameter to closely embrace the casing 20, and the lower portion of this bore is flared outwardly as at 5l) and then extends vertically as at 52, in order to telescope over the upper protruding end of the lower hanger bushing, forming a packing chamber of adjustable volume between the chambers which may be filled with a quantity of compressible packing material 54 of the permanent type such as well-known hydraulic packing.

It will be noted particularly that the packing chamber is closed at its upper end by the Wall 50 and at its lower end by the wall 42 and at its outer side by the wall 52, and it will be observed that the walls 50 and 42 are so tapered as to urge the packing in sealing relationship toward the outer wall of the casing 2. The packing chamber is open only toward the casing 2G, whereby, upon the application of substantial pressure to telescope the two bushings toward one another,

the packing will be compressed to form a permanent and protected seal around the casing 2U.

Below the wall 52 of the upper bushing, there is an outwardly and downwardly flared surface 55 of shape conforming with the surface 38, and this ared surface 56 terminates in a downwardly presented flat face 58. Surfaces 38 and 55 may be properly ground to form a metal to metal seal and their tapers are such with respect to the arrangement of the packing 54 and the packing chamber, that they impose a limit on the downward movement of the upper hanger bushing so that the packing 54 cannot lbe subjected to such excessive pressure as would tend to collapse the casing 2B.

The bore of the upper hanger bushing above the packing chamber referred to is provided with an annular cut-out 6l] in which there is a packing of the lip type and with the lips downwardly presented as shown, and there is a suitable port 52 extending through the wall of this hanger bushing between its packing rings providing access to the bore of the bushing between the lip packing 60 and the packing chamber 54, so that pressure may be applied to the port in the wellknown manner in order to test the effectiveness of the seal 54.V

There is an inwardly projecting ledge 64 at the upper end of the bore of the hanger bushing B2, providing a stop shoulder which would'serve to prevent any undesired upward movement of the inner casing 2t.

The manner of using this hanger assembly will be apparent from the above description and with further reference to Figures 3 and 4. With now conventional control equipment mounted on the casing head, such as the master drilling valve `V and the blow-out preventers P1 and P2 as shown in Figure 3, the lower hanger bushing B1 is positioned on the casing 26 and lowered through the control equipment until it reaches the seat in the casing head I2. When the lower hanger lbushing reaches its seat, it takes the weight of the casing on the slips 3i), and this weight is transmitted to the seat of the casing head I2, as will be clear from the teachings of the said patents and application referred to. Therefore, when the hanger is landed, the lower hanger bushing forms a permanent or primary seal closing off the upper end of the casing l) by reason of the pressure transmitted to its tapered portion and against the tapei-ed seat of the head I2 by the weight of the suspended pipe. Gf course, the operation of the slips and the slip cage is such that the packing in the chamber 52 is likewise compressed to form a temporary seal around the casing 20.

With the seals thus provided upon the initial landing of the lower hanger bushing, the control equipment shown in Figure 3 may be removed with safety, and on cementing time, and the permanent seal around the casing 20 may then be made up by the application of the upper hanger bushing B2 as will be apparent from the description of Figure 2. An appropriate quantity of packing is placed in the packing chamber andthe bushing B2 is forced downwardly toward the bushing B1 to reduce the volume in the packing chamber 54 and form the permanent seal referred to.

The bushing B2 is equipped with an exterior flange E5, and. there is a double studded holddown iiange F which has a portion rbearing against the upper face of the ange 55. The studs 68 extending from the hold-down'flange carry suitable nuts 'I0 which are manipulated to .positively pull the ange'downwardly toforce the bushing B1 toward the bushing B2: as illustrated in Figure 4.

`After the permanent seal is thus formed against the casing 2,0; its` effectiveness may be 4tested by means of the port 62 in a manner wellknown in the` art and as illustrated in Figure 4,

after which the upper casing head148 is. mounted -onand above the hanger bushingfBz forming a lseal againstthe tapered portion of that bushing and closing off the port 62 in a manner illustrated `in Figure 2.

A modification of the apparatus just described is shown in Figure 5. In this modification, 4the separate hold-down ring F is eliminated. The lower hanger bushing B3 may be -of the same gen- `eral construction as previously described or it may be the more simple `slip arrangement shown, in which case it is provided with apacking chamber 'I4 above the slip chamber, and this packing chamber would have a lip packing therein with the lips directed upwardly. `l'n this modication,

' the testing port is in the lower hanger bushing as `at 16, just above the packing chamberA 'M The upper hanger bushing B4 is of design similar to that previously described except that the test port and packingchamber 6B may be eliminated-in this modification. The operations performed in forming the permanent seal by compressing'the` packing 8D between these bushings will be` apparent from thef description previously given. Downward pressure is applied to the up- 4per `hanger bushing by tightening the nuts on the bolts-82 -which extendibetween the ilange lB'ofthe lower casing head and the flange`84 'of the upper casing head or tubing head-8S. The -head 86 has an inside tapered portion 88 which `seals with the external taper on the upper bush- -ing Bi and exerts downward pressure thereon to compress the-packing inthe chamber-80. In this arrangement, the effectivenss of the permanent `seal is tested after the upper casing headl is mounted by means of a suitable conduit 99 which maybe inserted between the Vbolts 82 and connested` with the port 1B.

It will be apparent that I have provided casing hanger assemblies wherein a complete seal is provided immediately upon landing of thelower hanger bushing. This seal consists of an outside `permanent seal where the exterior tapered wall of Athehanger bushing engages the tapered seat-in thercasing head and an inside seal against the outer wall of the casingcf less permanent character. This latter seal is then augmented by the application of a permanent seal'to the casing by mountingr the upper hanger bushing thereon, and telescoping it toward the lower lcasing headd, in order that the seal 54 may be tested prior to application of the head 48 if desired, the ring Fimay be considered as a part of the upper casing head in the sense that said *upper head consists of two parts ultimately attached together, and when so attached, the upper head not only exerts tension downwardly on the `bushing Bz to maintain the seal 54, but `also 6 maintains the sealing engagement .against the outer tapered surface of the upper. bushing Bz.

Iclaim.: i 1. A hanger assembly for suspending an inner casing within an outer casing comprising'separate lower and upper hanger bushings having bores to .closely embrace the inner casing, said lower bushing being of diameter adapting it .for lowering through control equipment of size rated with the outer casing and having `means tofgrip andsupport the weight of the inner casing, said lower bushing having anfeXterior surface provided with means to form a permanent seal with a lower casing head byatheweight of the'i-nner casing when .said lower bushing is landed .iin the lower casing head, said bushings having telescoping parts providing for `relative `vertical movement. between 'said bushings and being formed to. provide between them a packingrchamber of :adjustable volume closed at its upper, lower and outer sides but open at its inner side toward the inner casing, saidl upper` bushing having an exteriorisuriace for `the applicationiof a downwardly directed force to telescope-said parts and compressfpackingin said chamber to thereby form a permanent seal against the .ex-

terior of the inner casing.

2. A construction in accordance withl claim 1 whereinroneof'saidbushings is provided with a temporary seal in its bore positioned inispaced relationwith respect to said chamber to` seal with the inner casing and `with a` test port'extending laterally therethrough totestthe seal formed by the packing in said chamber.

3. A hanger assembly for suspending aninner casing withinnan outer casing comprising', separate lower and upperihanger bushings having boresto. closely embracethe inner casing, said lower bushingfbeing of diameter adapting it for lowering throughcontrol vequipment of size rated with the outer casing, and having means togrip andsupport `.the weight of the inner ca.sing,said lower bushing` having means in its bore `forming al temporary seal with .the inner casing and an exterior surface provided with means to form a permanent seallwith a lower casing 'head by the .weight of the inner casing when said lower 4bushing is landed in the lower casing head,said

bushings having` .telescoping parts providing-ifm' relative vertical movement between said. bushings and being formed to provide rbetween them a packing chamber of adjustable volume closed at its upper, lowerand outer sides but open `atits inner side toward the inner casing, said upper i bushing. having an exterior surface for the appli- `cation of a downwardly' directed force to telescope said parts and compress packing in said chamber to thereby form a permanent seal againstthe eX- terior of theV inner casing.

4. A'hanger assembly for'suspending an inner casing within an outer casing comprising separate lower and upper hanger bushings having bores to closely embrace the inner casing,..said lower bushing being of diameter adapting it for `lowering through control equipment of size rated with the outer casingrand having meansto grip and support the weight of the inner casing, said lower bushing having an exterior surface provided with means to form a permanent seal with a lower casing head by the weight of the inner casing when said'ilower bushing is landed inthe lower casing head, said bushings having Vtelescoping parts providing ,for relative vertical movement between Jvsaid bushings and: being 'formed to provide between them apacking: chamber of adjustable volume closed at its upper, lower and outer sides but open at its inner side toward the inner casing, said upper bushing having an exterior surface provided with means to seal with an upper casing head.

5. A h-anger assembly for suspending an inner casing within an outer casing comprising separate lower and upper hanger bushings having bores to closely embrace the inner casing, said lower bushing being of diameter adapting it for lowering through control equipment of size rated with the outer casing, and having means to grip and support the weight of the inner casing, said lower bushing having an exterior surface provided with means to form a permanent seal with a lower casing head by the weight of the inner casing when said lower bushing is landed in the lower casing head, said bushings having telescoping parts providing for relative vertical movement lbetween said bushings and being formed to provide between them a packing chamber of adjustable volume closed at its upper, lower` and outer sides but open at its inner side toward the inner casing, said upper bushing having anexterior flange thereon, a separate clamping ring adapted to engage said ange to apply a downward force thereto to telescope said parts and compress packing in said chamber to thereby form a permanent seal against the exterior of the inner casing, said ring being provided with bolts to engage the lower casing head to force said upper bushing downwardly.

6. A hanger assembly for suspending an inner casing within an outer'casing comprising separate lower and upper hanger bushings having bores to closely embrace the inner casing, said lower bushing being of diameter adapting it for lowering through control equipment of size rated 'with the outer casing and having its bore enlarged to provide a slip chamber within said bushing, slips in said chamber to grip and support the weight of the inner casing, said lower bushing having a downwardly and inwardly tapered exterior surface with means to form a permanent seal in the lower casing head by the weight of the inner casing when said lower bushing is landed in the lower casing head, said bushings having engaging parts providing for relative vertical movement between said bushings and one of said parts being recessed to provide a packing chamber of adjustable volume which is open toward the engaging part of the other of said bushings and toward the inner casing, and a member adapted to be mounted on said upper bushing in contact therewith and having adjustable means for engaging the lower casing head to force said upper bushing downwardly toward said lower bushing.

'7. A hanger assembly for suspending an inner casing within an outer casing comprising separate lower and upper hanger bushings having bores to closely embrace the inner casing, said `lower bushing being of diameter adapting it for lowering through control equipment of size rated with the outer casing and having means to grip vand support the weight of the inner casing, said lower bushing having a downwardly and inwardly tapered exterior surface with means thereon to form a permanent seal in the lower casing head by the weight of the inner casing when said lower bushing is landed therein, said bushings having opposed ends formed to receive and compress a quantity of packing between them and against the inner casing, said upper bushing having an upwardly and inwardly tapered exterior surface with means thereon to seal with an upper casing head mounted above.

8. An assembly for suspending an inner casing within an outer casing comprising a lowercasing head having a hanger seat, a lower hanger bushing of diameter adapting it for lowering through control equipment of size rated with the outer casing and having a bore to surround the inner casing with means therein to grip and support the weight of the inner casing, said lower bushing having an exterior surface formed to eect a permanent seal with said lower casing head by theV weight of the inner casing when said lower bushing is landed in said lower casing head, a separate upper hanger Abushing having a bore to surround the inner casing, said bushings having opposed ends formed to receive and compress a quantity of packing between them and against the inner casing to eiect a permanent seal against the latter, said upper bushing having an exterior surface to seal with an upperV casing head, and an upper casing head adapted to be mounted above and in sealing engagement with said sealing surface of said upper bushing, said upper casing head having adjustable means connected with said lower casing head to force said upper bushing downwardly toward said lower bushing to compress the packing against the inner casing.

9. An assembly for suspending an inner casing within an outer casing comprising a lower casing head having a hanger seat, a lower hanger bushing of diameter adapting it for lowering through control equipment of size rated with the outer casing and having a bore to surround the inner casing, said bore having an enlarged slip chamber with slips therein entirely enclosed within the lower bushing body to grip and support the weight of the inner casing, said bore having means therein to form a temporary seal with the inner casing and said lower bushing having an exterior surface with means thereon to eiect a permanent seal with said lower casing head by the weight of the inner casing when said lower bushing is landed in said lower casing head, a separate upper hanger bushing having a bore to surround the inner casing, said'bushings having opposed ends formed to receive and compress a quantity of packing between them and against the inner casing to effect a permanent seal against the latter, said upper bushing having an exterior surface to seal with an upper casing head, and an upper casing head adapted to be mounted above and in sealing engagement with said sealing surface of said upper bushing, said upper casing head having adjustable means connected with said lower casing head to force said upper bushing downwardly toward said lower bushing to compress the packing against the inner casing.

10. A hanger comprising separate lower and upper bushings having bores to closely embrace an inner casing, said lower bushing being s'o formed and of diameter adapting it for lowering through control equipment of size rated with the outer casing and having an exterior surface with means thereon to form a permanent seal with a lower casing head, said upper bushing having an exterior surface with means thereon to form a seal with an upper casing head, said bushings having telescoping parts providing for relative vertical movement betweeen said bushings and being formed to provide between them a chamber of adjustable Volume fora quantity of compressible packing of the permanent type which is closed at its upper outer and lower sides but open at its inner side toward the inner casing, one of the walls of said chamber having a tapered surface arranged to force said packing material toward the inner casing when said bushings are telescoped toward one another, and means in said hanger to grip and support the inner casing.

l1. A hanger comprising separate lower and upper bushings having bores to closely embrace an inner casing, said lower bushing being so formed and of diameter adapting it for lowering through control equipment of size rated with the outer casing and having a lower exterior downwardly and inwardly tapering surface with a packing ring thereon to form a permanent seal with a lower casing head, said upper bushing having an exterior upwardly and inwardly tapered surface with a packing ring thereon to form a seal with an upper casing head, said bushings having telescoping parts providing for relative vertical movement between said bushings and being formed to provide between them a chamber of adjustable volume for a quantity of compressible packing of the permanent type which is closed at its upper, lower and outer sides but open at its inner side toward the inner casing, one of the walls of said chamber having a tapered surface arranged to force said packing material toward the inner casing when said bushings are telescoped toward one another, and means in said hanger to grip and support the inner casing.

12. An assembly for suspending an inner casing within an outer casing comprising a lower casing head having an upwardly presented hanger seat and an upper casing head having means for attaching same to said lower casing head and having a downwardly presented sealing surface, a hanger comprising separate lower and upper bushings having bores to closely embrace an inner casing, said lower bushing being formed and of diameter adapting it for lowering through control equipment of size rated with the outer casing and having a downwardly presented exterior sealing surface with means thereon to form a permanent seal with said upwardly presented hanger seat of said lower casing head, said upper bushing having an upwardly presented sealing surface with means thereon to form a seal with said downwardly presented sealing surface of said upper casing head, said bushings having telescoping parts providing for relative vertical movement between said bushings and being formed to provide between them a chamber of adjustable volume for a quantity of compressible packing of the permanent type which is closed at its upper, lower and outer sides but open at its inner side toward the inner casing, and means in said hanger to grip and support the inner casing.

13. Oil well completion equipment comprising a casing head having an inside seat, a lower casing hanger section for supporting a well pipe in said head, said lower section having an outside surface adapted to engage said seat and form a seal therewith, an annular sealing element supported by said lower casing hanger section, an upper casing hanger section supported in intertting relationship by said lower section, whereby said sealing element is completely enclosed, and means for maintaining tension between said upper casing hanger section and said casing head, whereby said sealing element is forced into permanent sealing relationship between said Well pipe and said casing hanger sections.

ROBERT L. GRAIN.

REFERENCES CITED The following references are of record in the ile of this patent:

UNITED STATES PATENTS Number Name Date 2,313,169 Penick Mar. 9, 1943 2,400,254 Penick May 14, 1946 2,485,497 Lemley g Oct. 18, 1949