US 2751235 A
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Description (OCR text may contain errors)
June 19, 1956 Filed Oct. 16, 1952 FIGJ.
J. D. WATTS ET AL WELL HEAD PIPE SUSPENSION 3 Sheets-Sheet 1 IN VENTORS 58 JOHN D. WATTS 8 ELM 000 K. PIERCE, JR.
ATTOR NE YS.
June 19, 1956 J. D. WATTS ET AL WELL HEAD PIPE] SUSPENSION 5 Sheets-Sheet 2 Filed Oct. 16, 1952 INVENTORS JOHN D. WATTS ELWOOD K. PIERCE,
WfiM/XZW ATTORNEYS m H w m W f F n 1956 J. D. WATTS ET AL 2,751,235
WELL HEAD PIPE SUSPENSION Filed Oct. 16, 1952 3 Sheets-Sheet 5 INVENTORS JOHN D. WATTS 8 ELWOOD K. PIERCE, JR.
ATTORN "Y5 United States Patent() WELL HEAD PIPE SUSPENSION John D. Watts and Elwood K. Pierce, assignors to Gray Tool Company, poration of Texas Jr., Houston, Tex., Houston, Tex., a cor- The present invention relates to well head pipe suspension equipment having means for sealing against an oil well pipe, such sealing means being characterized by its instantaneous and intensified sealing action, when it is subjected to any pressure which may exist in the well. The invention provides for the suspending and sealing of an oil well pipe, in the well head, while providing for complete mechanical control of the well at all times, during the operations which are involved. In particular, the invention is concerned with a hanger for suspending oil well pipe in the well head, which provides for the forming of an effective seal at the instant the hanger is landed in the well head, which seal is strengthened or made more eflfective, depending on the pressure which it is subjected to, at the time the hanger is landed, or at any later time, when an increased pressure condition arises in the well.
A further object of the invention is to provide equipment for suspending a pipe at the well head, including a novel sealing element which is so constructed and arranged, that it will respond to pressure exerted upon it, either from below, or above, to intensify its sealing action against the outer Wall of the pipe which is being suspended.
The invention may be employed, for example, with a hanger for use in building safe oil wells by the methods described in United States Patents Nos. 2,117,444, May 17, 1938, and 2,082,413, June 1, 1937, to Mueller and Yancey. The description of applicable structure and steps in operation which appear in these patents is not repeated in detail herein, it being understood that they are referred to as showing equipment and methods which would be used with the present invention and to that extent they form part of the present disclosure.
Further, United States Patent No. 2,207,469, to Roye, July 9, 1940, discloses a practice analogous to the said Mueller et al. patents but wherein provision is made for pulling the casing upwardly after the hanger is landed to remove the slack and put a strain on the casing, slip means being provided in the hanger to support the pipe after the strain has been taken. The present invention contemplates use of a hanger with the method of landing a casing as disclosed in the above mentioned Roye patent but having further refinements of the practices disclosed therein. Therefore, the Roye patent is mentioned to disclose the details and description of an applicable structure in the operation of landing a casing in a casing head and such steps are not repeated herein in detail, it being understood that they are referred to as disclosing well known equipment and methods which would be used with the present invention, and to that extent they form part of the present disclosure.
An object of the invention is to provide a hanger wherein an effective seal is had both between the pipe and the hanger, and between the hanger and the casing head at the instant the hanger is landed. The above mentioned seals are important because they are necessary if the well is to be kept under complete mechanical control at all times. i
Another object of the invention is to provide a seal ing unit forming a part of the hanger which is auto= matically expanded by the well pressure when the hanger is landed, to seal between the hanger and the pipe being suspended, the seal thus formed being thereafter maintained by the well pressure for as long a time as required. We disclose herein such a unit including a sealing element which may be expanded by the pressure exerted thereon from either above or below the sealing element.
The hanger and associated equipment disclosed herein, is a further improvement upon the equipment disclosed in a co-pending application of Mueller et al., Serial No. 680,334, filed June 28, 1946, now Patent 2,624,413, January 6, 1953, and has the advantages and capabilities of the equipment disclosed in the said copending application, which advantages and capabilities are not repeated in detail herein, it being understood that the said co-pending application discloses equipments and methods which would be used with the present invention, and to that extent thesaid co-pending application forms a part of the present disclosure.
In the present application, reference is made to now well known control equipment, including master drill-.
ing valves and blowout preventers. It will be understood that such control equipment as is referred to, is of the now recognized and standardized rated size, with respect to the casing on which it is mounted, and that such control equipment is of the full open type, having a bore therethrough substantially equal to the maximum diameter of the hanger seat above which it is mounted, whereby all operations requiring the full width of the casing previously landed may be carried out, through the control equipment, the construction of the equipment being such that the hanger may be passed through the control equipment to its ment removed, while providing complete mechanical control of the well throughout all of the operations which are involved.
Another object of the invention is to provide a sealing unit having a sealing element therein, to contact and seal with the pipe being suspended, which is of such design that the pipe and the unit may be moved relatively to one another, without damaging those surfaces of the sealing element which engage the pipe. The sealing element of the present invention is distorted in shape, by well pressure, to effect an intense seal, yet the construction is such that the sealing element will resume its normal or relaxed shape, when such pressure is no longer present.
ing element, as by mechanical pressure applied thereto, is not required in order to complete, or intensity its sealing action, as is the case in prior art seals of the ordinary packing type.
A further important object of the invention is to provide well head pipe suspension equipment, capable of use in building a well, while maintaining complete meinvention, and are not intended to restrict the invention to any precise form, or confine the use of -the invention to the particular operations or association disclosed herein.
In the drawings: Figure 1 is a vertical sectional view through an illustrative well head installation,
showing an inner casing being landed through the controlequipment, mounted on the outer casing.
Figure 2is a partial vertical sectional view tl'rro ugh a seat, and the control equip- The sealing unit and the sealing element are so constructed, that permanent deformation of the sealportion ofa well head; showing a casing hanger landed in the casinghead; thecondition of the partsillustrated being that which exists just prior to the time the weight of the casing is taken on the slips in the hanger.
Figure 31is a verticalsectional view similar to Figure 2, but showing the conditionof the parts when the inner casing is supported by theslips in the hanger.
Figure4fis a horizontalsectional view taken along the line 4-4 ofFigure 3*.
Figure, 5 is a horizontal sectional view taken along the line 5"5'of Figure 3.
Figure 6 is a partial vertical sectional view taken through the lower end of the shank of the hanger, showing details offtheslip guiding means, which. prevent the slipassembly from Lunthreading from the hanger.
Figure 7" is a vertical" sectional, view taken through a,well' headiassembly, comprising three strings of pipe, showing-the manner in which theupper casing heads seal against thevupper tapers, of the hangers.
Figures. 8, 9 and, 10} are partialj vertical sectional views of the, sealingunitandsealing ring, showing the sealing action ofrthe, latter, ,in response to pressureexerted upon the. sealing ring.
Figure 11 is a detail view, partly in section, of the sealing, ring.
Figure 12. is avertical sectional view through a modified hanger, construction.
Figure 13 isapartial vertical sectional view, showing the top .portionofthe hanger illustratedin Figure 12, and the, associated. portionof the'upper casing head, which is positioned above this hanger.
Referring to Figure 1, there is an outside casing C andan inside casingstring C is-shown beinglandedwith inthe outside. casing. Onthe outside casing, there is theusual casing head, 10, which has a fullopen bore 12. therethrough, and. an upwardly and outwardly flaring. ha gmiseatlhat.theupper end of 'itsjbore. Mounted on the casing head, ,as by, flange or other suitable type connections, isnow conventional control equipment, having a ,bore, substantially. equal to the. maximum diameter of the seat 14. The items of control equipment may vary dependingon the welhwhich is being built, andmay comprise. simply. a. blowout-.preventer, or a pair of. blowoutpreveuters, or -the.-usual. master drilling valve-1 plusone onmoneblowout preventers. In .the illustration of Figure l, a, master. drillingvalve 16 isshownmounted. on thecasing, head,. surmounted by apair of: blowout preventers 18 .anrl.29. The hangeris generally designated-as-H, and as .fully described in the patents andapplication referred to,. afterthe well. casing-C the casing C is-lowered throughthe control equipment, and ,at the proper time, the-hanger H is slid ably positioned on the casing-C and lowered to its positionnto seatand seal in. the, casinghead 10. At this time,
the, control-equipment may be-removed, it being under- 5 stood-that the casing-,C -is provided withlthe usual inside control means, comprising a removable back.- pressure valve, Thereafter, fur-then casingmay be run, involving thernoun ting ofna-p-further .casinghead, ortubing may be run, the latter operation involving the tubing head. ln. -Fig ure.-7, a completion involving threestri ngs of pipe isgillustratem the control equipment and procedures whichare involvedato for-m this structure being; fully described initheepatents and. applications referred to above.
Referring to Figurc.
the, seat,. 14 ofethegcasrng head 10, the par-ts being in that,
condition, which they 1 assume- 1 1st. prior to the; time whenthe inner casing Q is, supportedlby the-slips intthe t hanger. The hanger comprises a body having a bore-'22-extending therethrough. this: bore beingslightly; larger than the outside.diarneter .of.,the.-irme11,casing C in order that it may, beslidably p9sitioned gthereorn There'is tan-enlargedwhich extendsz throughout counterbore 24 in the hanger, e eaz lwit et sugnding haulsf S dither-hanger, andeto has been drilled through the mounting. of a 1 2, the hanger H is shown landed in the lower end thereof. The inner wall of this counterbore isformed to receive arrdsupport the slip assembly," the construction of the wall of the counterbore and that of the slip segments which form the slip assembly, being described and claimed in a co-pending application of John D. Watts and Elwood Kn Bierce; Jr., entitled Oil Well Hanger Assembly,? Serial No. 313,706, which was filed on October 8; 1952. The interior wall" of the counterbore:24*is1formedswitlra:continuousispiral surface, havingdownwardly and: inwardlyincl-ined slip; guiding' areas 28 positioned one above another in vertical alignment: Similarly andexactly cutinclined exterior areas30rare provided on the outer walls of the slip elements. The areas 28 on the wall of 'the counterboreare separated by continuous downwardly presented horizontal spiral cut ledges 32, and the guiding areas 30 onthe slips are separated by similarly formed ledges 34L The.surfaces28zand'3tlare formed by spiral surfaces of. fixed lead,- the surfaces 28 extending from the upper end of. the. counterboreto the:
lower open end thereof, so thatthe. slip.assembly can-.be threaded'upwardl y into. the counterbore, through thelowerend thereof, andv the. hanger can be;unthreaded from the slip assembly, asdescribed in said .co-pending. application of Watts and.- Pierce,,. entitled Oil Well. Hanger Assem? bly,'as referred. to above. The surfaces 28 and .30, and the ledges 32: and 34, are cut or formed as described in Mueller et.al;, 2,624,413.
As described in the Watts etal. application just referred to, there are four arcuate slipsegments. L which make up the slip assembly, and they areseparated from one another by slots 36. In cutting, the slots between the segments, sufficient of the metal may be-removed so that the slip segments may move toward. one. another as they grip the pipe, during their movementfrom the position ofFigure Zto that of Figure 3. The movement of the slips, between retractedand operative positions, is a limited vertical, and. inward movement of the. slip segments, which is. permitted by the formation of the inner wall of the counterbore and the formation of the outer walls of the slip. segmentS as previously described. Asishownin Figures 2' and 3; the inner. faces of'theslip segments are formed with upwardly presented gripping,
teeth 38, whichgrip. and suspend the pipe in the usual manner, as is well known, in theart. In Figure 2, .the slip segments are shown in their upper or retracted positions, which they assume when the hanger body is slidably moved downwardly over the upper end of'the casing C thefriction, tending to move the slip segments upwardly and away from the casing C When the hanger is landed in the casing head, and when the usual upward support of the derrick on the. casing C is released, the slip segments are causedby the casing to slide downwardly controlled by the engagement of the surfaces 28 and-'30, and as the segments move downwardly, they move inwardly whereby their teeth engage the casing to'support and suspend *the same;
As described" in the-Watts'et al.- application referred to, theinner faces of the' slip segments may also: be for-med with a groove, as shown in Figures 2 and 3 which is 1 continuous from: one segment to another when sameare in proper alignment, the= said-groove being outof' be; threaded; through the: openings :44 extending through: the shank; of the r hanger: and: :into: threadedlopenings; 46 rin the:body-.ot-.-.the -slip segments..(Figure:-3),,in order to. lock the slip segments in their retracted positiom-asshowrr.
in Figure 2. As disclosed in the Roye patent referred to above, when the hanger is initially slidably positioned over the casing, the set screws are removed from the openings 44 and 46, before sliding the hanger downwardly through the control equipment, thereby releasing the slip segments for downward movement, when the hanger reaches the landed position, as shown in Figure 2.
As shown in Figures and 6, the shank S of the hanger is provided with openings 43 and guide screws 50 are threaded through these openings after the slip assembly is initially installed to proper position within the counterbore of the hanger body. These guide screws pass between the adjacent edges of the slip segments, and when so positioned, they restrain the slip segments against any unthreading movement.
With the construction as described, the slip assembly may be assembled into a unit and threaded upwardly into the counterbore of the hanger body and the guide screws 50 and the set screws may then be installed to hold the slips in their proper retracted positions. Upon removal of the set screws, the hanger may be passed downwardly through the control equipment to its seat, as shown in Figure 2. When the tension of the casing C is released the slip segments move downwardly to the position of Figure 3, to grip and support the casing in the well head. At this time, a seal is formed between the outer wall 51 of the hanger with its well known packing rings 53, and the seat 14 of the casing head as shown in Figure 2. At the same time, a seal is formed between the bore of the hanger and the outer wall of the casing C as hereinafter described. It will be understood that the hanger may be reset, if the initial setting is unsatisfactory, as described in the co-pending application of Watts and Pierce, referred to above.
The shank portion S or" the hanger body is of relatively great length, and the slip segments themselves, are of relatively great length, as compared with hangers of this type known in the art. The suspension area where the slips engage the casing C is positioned below the suspension area where the hanger engages the seat of the casing head.
Upon removal of the control equipment, and prior to the mounting of the next tubing or casing head, as described in the prior patents and applications previously referred to, the hanger may be permanently secured to and sealed to the casing, as by welding the same as indicated at 52 in Figure 3. Such a welding operation is customarily performed after the control equipment is removed and when the casing is supported by the slip segments, the hanger being in turn supported in the bowl of the casing head. Another practice for permanently sealing the hanger to the casing is disclosed in a copending application Serial No. 650,272, Mueller et a1. filed February 26, 1946, now Patent 2,620,880 December 9, 1952. In that application, a hanger and associated means are disclosed, providing for the cold rolling of the easing into permanent sealing engagement with the hanger in order to form a permanent union between the casing and the hanger. The details and description of applicants structure and the steps in the operation which appear in the application just mentioned above, are not repeated herein, it being understood that they are referred to as disclosed equipment which could be used with the present invention, and to that extent they form a part of the present disclosure.
In order to provide for effectively sealing the space through the bore of the hanger around the casing C at the instant the hanger is landed and when it assumes the support of the inner casing, we provide a sealing unit which is automatically operable to seal the Well, and which is actuated and made more intense by any pressure which may exist in the well. This sealing unit is disclosed in Figures 2 and 3, and in more detail in Figures 8 through 11. In general, the sealing unit or assembly comprises a well head member, such as the hanger H, with its longitudinal bore to receive the casing C or other oil well pipe, a recess 54 in said bore, and a sealing element or ring 56, the configuration of which is best shown in Figure 11. The sealing ring is of expansible construction, being made of rubber, synthetic rubber or rubber composition, such as neoprene. It is flexible and resilient, and of such design and construction that it may be expanded, or deflected and distorted by well pressure, after which it will resume its normal relaxed condition as shown in Figure 11. While not intending to limit the nature of the sealing ring, we have constructed the same as shown in Figure 8, and as hereinafter described, of rubber or rubber composition, or of synthetic rubber, such as of a composition of hardness neoprene. The sealing ring has outer walls to engage the wall 54 of the recess in the bore of the hanger and an inner sealing wall which protrudes from said recess, as hereinafter described, to slidably engage the outer wall of the casing C the sealing ring being formed and arranged in said recess to admit fluid under pressure from the bore of the hanger into its hollow interior to expand its walls into intensified sealing engagement with the wall of said recess and the casing at the instant the hanger is landed in the casing head.
The enlarged recess 54 in the bore of the hanger is located below the welding point 52 (Figure 3), and preferably above the slip chamber and it extends entirely around the bore of the hanger. This recess is of substantial depth, and is preferably located above that thickest portion of the hanger which seats in and seals in the bowl of the casing head. The recess is shown in Figure 3 as having a curved outer wall, and straight top and bottom walls. There may be some variations in the shape of this recess. For instance, the corresponding recess for the sealing ring in Figure 13 has an outer wall which is not tapered in form, but is machined on a constant diameter, and this design of the recess may be employed in the hangers as well as in the part 92 of Figure 13. The recess is closed by these walls just mentioned, but it is open to the bore of the hanger at its inner side. The sealing element 56 is of such size that it snugly fits within the recess 54, substantially filling this recess, and protruding slightly beyond the recess, at the inner side thereof, in order to engage the well casing C as shown in Figure 8. The design of the sealing ring is such that an initial circumferential tension maintains it in contact against the inner pipe C as shown in Figure 2, under neutral pressure conditions, whereby a constant low pressure seal is provided. Under these conditions, there is also an initial radial compression of the sealing element against the inside wall of the recess 54. These sealing contacts as just referred to, are present even if the inner pipe is oversize, undersize, or if it is off-center with respect to the hanger bore.
The sealing ring 56 is hollow, providing an interior pressure chamber or cavity, extending entirely around and within the ring, consisting of a first chamber portion 58 and a second chamber portion 60, as shown in Figures 8 through 11. This pressure chamber is in part defined by the. first sealing wall portion 62 and a second sealing wall' portion 64 as disclosed in Figure 8. The central wall portion 66 has an inner surface which in the normal or relaxed condition of the sealing element, is parallel to the borethrough the hanger, or parallel to the axis or outer surface of the casing against which the ring is adapted to seal. The first and second sealing wall portions 62 and 64 have inner surfaces which taper outwardly slightly from the surface of the wall portion 66. In the central wall portion 66, or in that portion of the sealing wall which is disposed between the wall portions 62 and 64, there are one or more openings 68, leading into the interior pressure chamber of the sealing element. The number of holes provided may vary with the size of the sealing ring, and we show herein an acceptable design, wherein one of such holes is provided every two 7 or three inches around the circumference of the sealing ring.
With construction as described, the wall portions 62 and '64 constitute upwardly and downwardly presented flexible sealing lips, which will serve to seal against pressure coming from the direction toward which these lips are presented. The web portions 70, in the central wall, between the openings 68, serve to connect these pressure lips at spaced points, whereby the sealing ring may be slidably moved along the inner pipe C in either direction, without tearing or injuring the sealing lips referred [0.
When the hanger is applied to a well casing, or other pipe, and when it is lowered through the control equipment to its seat, the sealing ring normally maintains the shape for which it was designed, as shown in Figures 8 and ll, and in the absence of an excess of pressure either above or below the sealing ring. If the well is quiet, the hanger is lowered through open control equipment, and the sealing element will not be subjected to pressures which would distort it from its normal or relaxed condition. If some pressure exists in the well, it might be that the upper blowout preventer 20 (Figure 1) would be closed after the hanger is passed below the same, but prior to the actual landing of the hanger, pressure exerted upon :the sealing element from below and above the same are equalized.
Assuming that some pressure condition exists in the well immediately upon the landing of the hanger in the seat of the casing head, that pressure within the casing C of the well, or other casing above which the hanger is being landed, immediately exerts its full effect upwardly through the bore of the hanger and upon the sealing ring, to distort same into its intense sealing condition, as :is illustrated in Figure 9. Thus, when the hanger is landed, any upward passage of Well pressure exteriorly of the hanger, is prevented by reason of the seal formed by the outside lower tapered surface 51 of the hanger when it lands in the bowl of the casing head, but at this time fluid under pressure may pass upwardly through the bore of the hanger past the slip means, and when this pressure reaches the sealing ring 56, and if it is of sufiicient intensity, it will deflect those portions of the first sealing wall portion 62 below the openings 68, outwardly, thus exposing the opening or openings 68 to the well pressure and permitting same to enter the pressure chamber within the sealing ring, as is illustrated in Figure 9 by the arrow which illustrates the movement of the fluid under pressure through the exposed openings 68.
Upon entering the pressure chamber within the sealing ring, and when suflicient pressure is built up therein, which will be substantially instantaneously upon the landing of the hanger, the effect will be to expand the second sealing wall portion 64 of the sealing ring inwardly into tight engagement with the outer wall of the casing C This pressure acting within the pressure chamber will also press the outer and upper wall or lip 72 of the ring outwardly into pressure tight engagement with the outer wall of the recess 54. The material from which the sealing ring is made of sufliciently deformable nature, to be pressed by this pressure, to some extent, upwardly into thespace between the bore proper of the hanger, and the outer wall of the casing, as shown at 74 in Figure 9.
While the outer wall of the sealing ring may be closed, and made sufliciently flexible to permit the reaction of the sealing element to the pressure, as described above, we have found that the proper flexing of the ring to and from sealing positions is facilitated by having the outer wall of the ring cut away, as at 76, throughout the entire periphery of the sealing ring, whereby its upper and lower portions may rapidly respond. Variations of the design in this respect may be provided, and satisfactory results may-be'obtained by simply cutting away the outer wall of the sealing ring at spaced. points of substantial length, rather than cutting it away throughout its entire perimeter, as indicated at 76, and referred to above. Of course, the chamber within the sealing ring is closed, at its outer side, by the wall of the recess in which the ring is positioned, the action of the pressure within the chamber of the sealing ring, being such as to expand the outer lips of the sealing ring, against the walls of the recess.
In operation, when the hanger lands on its seat, the full pressure within the casing C is instantly exerted upwardly against the first sealing wall portion 62, deflecting it outwardly as shown in Figure 9 to enter the pressure chamber within the sealing ring, where it then acts to press against all portions of the upper part of the sealing ring to form an intense seal between the hanger and the casing. A seal within the bore of the hanger is thus instantly formed, at the moment the hanger is landed. The seal is effected by the well pressure being controlled, and it is made more intense and more efiective as the well pressure increases. Accordingly, even though an intense pressure condition exists in the well, by reason of the condition of, or the absence of mud fluid therein, this seal will be instantly efiective, and will be constantly maintained and augmented by the pressure which is encountered. When the hanger is landed, the weight of the casing is taken on the slips in the hanger body, and the weight of the casing thus completes the seal formed by the outer surface of the hanger against the bowl or seat of the casing head.
With an arrangement as described, it is possible to remove the control equipment while maintaining complete mechanical control of the well, in preparation for welding the hanger to the casing, or rolling the casing to the hanger, as previously described. Of course, the invention herein may be used where seals other than those formed by welding or rolling are desired; for instance, this invention may be used in association with that of Patent 2,568,581, Crain, which issued on September 18, 1951, and which shows an alternative seal formed by the compression of packing. Complete mechanical control is maintained throughout all of the operations referred to, both within and around the casing being landed, the usual back pressure valve being employed within the casing, as required, to resist any undesired flow of fluid through the casing, as is well known in the art. By reason of the availability of this effective seal, instantly operable, and by well pressure when the casing is landed, a great flexibility in the selection of operations at this stage is permitted, and various adjustments of the casing may be made, as required, with the well under complete mechanical control at all times. ,7
It will be understood that the precise design of the sealing ring may be varied. The design includes the hollow pressure chamber and the protruding sealing wall, which normally engages the outer wall of the casing, the sealing ring being formed and arranged in its recess to admit fluid under pressure from the bore of the hanger into its hollow interior to expand its Walls into intensified sealing engagement with the wall of the recess and the casing. In the design described herein, we have disclosed an arrangement wherein the pressure is admitted to the interior of the sealing ring, by openings in the protruding sealing wall, which are exposed when the pressure in the well rises to a sufficient extent to press the wall outwardly, as in Figure 9. The sealing wall has two portions, one of which is forced outwardly by the pressure, and the other of which is forced inwardly by the pressure into more intense sealing engagement with the oil well pipe.
Comparing Figures 8 and 9, when the hanger is landed and pressure acts within the pressure chamber of the sealing ring, the first or lower portion 58 of the sealing chamber is reduced in volume, whereas the second or upper portion 60 of this chamber is increased in volume. Thus, entry of fluid under pressure and the resulting sealingaction, changes the shape of the pressure chamber in cross-section, the upper or second portion thereof being expanded, whereas the first or lower portion thereof is contracted.
The design of the sealing ring, and the recess in which it is positioned, are symmetrical, and we use the term first sealing wall portion to denote that wall portion which is toward the fluid under pressure, no matter from which end of the ring it may come. Similarly, the term second sealing wall portion is used to denote that wall portion which is remote from the pressure source. In Figure 9, the lower wall portion 62 is presented toward the source of pressure, but Figure discloses that the sealing unit and ring will operate in the same manner, to seal against pressure coming from the opposite direction. In Figure 10, the wall portion 64 would be the first sealing wall portion, in the sense that it is presented to the source of pressure, while the wall portion 62 would be second sealing wall portion, in the sense that it is remote from the source of pressure. In this figure, portion 64 is defiected outwardly above the openings 68 and wallportion 62 is pressed inwardly into engagement with the casing as a result of the action of the fluid under pressure entering the pressure chamber of the sealing ring.
The symmetrical design and action of the sealing unit, wherein it will operate in the same way in response to pressures from opposite directions increases the usefulness of the invention in well head equipment. It has long been the practice to test welds, or other seals, in various arts, by closing off a space adjacent to the weld and subjecting this closed ofi space to fluid under pressure, in order to test the weld. This conventional practice has been applied to oil wells. For instance, and referring to Figure 3, the weld 52 may be tested by projecting fluid under pressure through a conventional fitting 78 which provides an opening into the space between the weld and the sealing element 54, as is well known in the art. The test fitting 78 has a radial port therein, and it may be closed by a suitable cap screw or the like when not in use. An ordinary pressure gun for discharging fluid under pressure, may be employed in this test. The sealing element will act as described and as illustrated in Figure 10, to hold this pressure, which may then be built up in the confined space to determine the condition of the weld seal 52, as is conventional.
The sealing element described herein has no loose protruding edges or lips which might become torn by engagement with the wall of the pipe which the sealing ring surrounds. The inner lips of the sealing ring are joined together, permitting relative motion between the sealing ring and the pipe in either direction, while eliminating any roll back or tearing off of either of the lips. This allows the seal to be slidably moved downwardly around a pipe against well pressure, without damage to the sealing ring.
Referring again to Figure 7, it will be understood that the inventions and practices described herein may be employed in the running and landing of successive casings, the successive casing heads being mounted on the well one above another, and terminating in a tubing head. As stated, the novel sealing unit, and associated means described herein, provides for complete mechanical control of the well both within and around the hanger,
at all times, and at the instant the hanger is landed. By.
reason of the above, the control equipment can be safely removed after the casing is landed, or after cementing, in order to immediately perform various operations, such as rolling or welding the casing to the hanger, and cutting off the end of the casing, in order to secure additional casing or tubing head equipment above the hanger which has been landed.
Referring to Figures 12 and 13, a modified hanger design H is disclosed, in which the sealing element 80, of the same design, is positioned in a recess 82 of the same design as previously described, near the bottom of the bore through the hanger, and below the slip means as shown in Figure 12. The slip means is of construction as previously described, in connection with the principal embodiment, except that the slip assembly must be inserted through the upper end of the hanger bore, in a manner as described in connection with Figure 10 of Mueller et a1. 2,624,413, previously referred to. While a hanger design of the double tapered type shown in Figure 10 of that application may be employed, we show in Figures 12 and 13, a casing hanger of modified design having a lower taper 84 and an upper taper 86 of shorter vertical dimension, and the upper end of the bore through the hanger is closed by a cap 88 which is welded to the hanger, and to the casing C as indicated in Figure 12, after the slip assembly has been inserted. In other respects, the construction of the hanger and slip assembly is as previously described. If desired, a further seal around the casing C may be provided by the same type of recess and sealing ring, as indicated at 90 in Figure 13, this recess and ring being arranged within the bore of an upper casing head or tubing head 92.
Referring to the construction and operation of the sealing ring, it will be understood that the openings 68 therein will serve to prevent any blow-by of pressure between the pipe and the seal, as such pressure as might tend to pass between these parts will expose the openings, thus permitting entry of the well fluid into the internal cavity of the sealing ring, to make effective the pressure seal as previously described. In certain cases, however, it may be possible for the pressure to pass around the outside of the lower end of the first or leading sealing lip, and thus around the outside of the sealing ring to enter the pressure chamber thereof, thus effecting the seal in the manner described above. The design of the sealing ring may be varied, including a design with joined lips on the inside only, as described, or joined lips on the outside only, or joined lips both on the inside and outside of the sealing ring. It will be understood that various other changes may be made in the construction described herein, without departing from the range of the invention.
As stated, the invention is not confined to the precise construction and associations disclosed herein. While the sealing ring is disclosed in the principal embodiment, as employed in a casing hanger, it may be usefully employed in other parts of the well head, for instance, the ring may be usefully employed in a tubing hanger, and elfectively used to control the pressure of the well in completion operations, involving the landing of the tubing. While the sealing ring is shown in Figure 3, as being augmented by a weld seal at 52, depending on the circumstances and the material used, the sealing ring itself may serve as a permanent seal around the inner casing, being maintained and intensified, in accordance with the pressure existing in the well.
1. For use between an oil well pipe and a well head member having a bore of slightly greater diameter than the outside diameter of the well pipe for receiving the well pipe and an annular recess open at one side toward the well pipe and closed at its opposite side; sealing means for providing a pressure-tight seal between the Well pipe and Well head member and operable upon an increase of fluid pressure from either axial direction to move into increased pressure-tight engagement, said sealing means comprising an annular pressure deformable sealing ring of rubber or the like adapted to be disposed within said recess, said ring being of a size to substantially fill said recess and having a relatively thin wall arranged to protrude beyond the open side of said recess into slidable pressure tight engagement with the exterior surface of the well pipe, relatively thick end walls extending from the edges of said first-mentioned wall toward the closed side of said recess, and integral wall means disposed on the free edges of said end walls arranged to engage the closed side of said recess and defining with said first-mentioned wall and said end walls a circular pressure chamber within said recess, the protruding part of said first mentiened that an increase in fluid" pressure from either axial direction is operable to move the adjacent lipout of engagement with the exterior surface of thewell pipe to thereby permit said increasedpressure to enter saidpressure chamber'tlirough said opening and urgetheo'ther lipinto increased pressure-tight engagement with the exterior surface of the Well'pipe.
2. Sealing means as defined in claim 1- wherein said wall means comprisesspaced lip portions;
R ferenc'es Citedin' the file of this patent UNITED STATES PATENTS