US3001803A

US3001803A - Wellhead

Info

Publication number: US3001803A
Application number: US583104A
Authority: US
Inventors: John D Watts; James C Ireland; Erwin F Hill
Original assignee: Gray Tool Co
Current assignee: Vetco Gray LLC
Priority date: 1956-05-07
Filing date: 1956-05-07
Publication date: 1961-09-26
Anticipated expiration: 1978-09-26

Description

Sept. 26, 1961 J. D. WATTS ET AL 3,001,803

WELLHEAD Filed May 7, 1956 2 Sheets-Sheet 1 INVENTORS: 4 Jjohn .D. VVufl's, mlames C. Ineland z EzyvjnFHjll ATTORNEYS.

Sept. 26, 1961 J. D. WATTS ET AL 3,001,803

WELLHEAD Filed May 7, 1956 2 Sheets-Sheet 2 1 24 INVENTORS. ijbhn Do James 0.1 rpland};

Ezyufin R Hill ATTORNEYS.

LLHEAD Houston, Tex., assignors to Gray Tool Company, Houston, Tex., a corporation of Texas Filed May 7, 1956, Ser. No. 583,104 4 Claims. (Cl. 285-137) The present invention relates to wellhead equipment useful in the completion and flowing of wells which it may be desired to produce from different levels or straturns.

The invention provides a compact wellhead structure wherein separate strings of tubing may be hung and supported in a hanger bushing, which in turn is supported, sealed and secured in the tubing head. The assembly of the invention includes a relatively large hanger bushing with a plurality of openings therein, and smaller hangermembers for each string of tubing which are supported in the larger hanger bushing. The smaller hangers are of the double tapered type, and have upwardly extending lips which are adapted to seal in sockets in the wellhead parts above the tubing head, such as a cap and associated assembly which is formed with passages to provide for flowing the well from the separate levels or stratums.

In the drawings:

FIGURE 1 is a vertical sectional view of a wellhead installation in accordance with the invention.

FIGURE 2 is a fragmentary verticalsectional view of that portion of the wellhead where the upwardly extending lips of the smaller tubing suspending hangers contact the surface of the well head part with which they seal.

FIGURE 3 is a fragmentary illustrative vertical sectional view showing the difference in taper of sealing cones used in the wellhead, and the parts with which they seal.

Referring to FIGURE 1, a tubing head is shown mounted on the wellhead above the surface string of casing 12, the tubing head being sealed to a hanger 14 in a manner well known in the art. The casing 12 may be sealed to the casing hanger 14 as by welding as indicated at 16. The tubing head has conventional side outlets 18 and 20 adapted for connection with conventional valves (not shown) for control of flow to and from the interior of the casing 12 as is well known in the art, and these outlets may be interiorly threaded for the reception of closure plugs, as is Well known in the art.

The tubing head has an outwardly flaring bowl or hanger seat 22 at its upper end, which is adapted to receive a unitary hanger bushing 24 of novel design. This hanger bushing is of generally circular cross-section,

like hangers well known in the art, and it has a conical or tapered exterior surface 26 adapted to land and seal in the seat 22, as is well known in the art, this surface being provided with hydraulic packing rings as shown, to effect the seal. The upper flange '28 of the tubing head is provided with a. plurality of openings extending radially therethrough, to receive locking screws 30' having ends 32 which engage the upper inwardly tapered end of the hanger 24 to lock same in the tubing head.

It will be understood that the hanger 24 is of such size that it is capable of suspending two strings of tubing in the casing 12, there being spaced vertical passages 34 and 36 extending entirely through the hanger 24. The upper ends of these passages 34 and 36 are outwardly tapered as at 38 and 40, forming seating surfaces to receive and support, respectively, the double

tapered hangers

42 and 44.

The

hangers

42 and 44 have openings extending entirely therethrough, and at their lower ends they are threaded as at 46 and 48 to connect with the upper ends of the

tubing strings

50 and 52.

The double

tapered hangers

42 and 44 are provided with interior circular recesses or grooves 54 whereby removable back pressure valves or plugs may be installed in the tubing hangers, to control flow therethrough.

' These double tapered tubing hangers are interiorly threaded as at 56 for the attachment of a lift nipple or pipe, whereby, they may be manipulated in the well, through control equipment.

It will be understood that in landing the tubing and hanger assemblies just described, suitable control equipment such as master drilling valves and blowout preventers of proper rating and bore may be mounted on the tubing head 10, so that the tubing and hanger assemblies may be lowered therethrough into the seat of the tubing head 10, while maintaining mechanical control of the well. It will also be understood that the locking screws 30 are sealed in the flange of the tubing head, by appropriate stufling boxes, so that they may be manipulated as is well known in the art, to engage or release the hanger 24, without permitting escape of fluid from the well.

After the hanger assemblies are landed in the tubing head, and the control equipment is removed, a tubing head top or cap 58 may be mounted on and above the flange 28 of the tubing head, being sealed thereto by means of the conventional A.P.I. ring gasket 60. The cap 58 is provided with a shoulder 62, and a corresponding shoulder on a locking ring 64 is adapted to engage this shoulder, the locking ring being tightly secured to the flange of the tubing head, by a plurality of spaced bolts 66, extending around the flange and ring.

The cap 58 is provided with a pair of vertical openings 68 and 70, which are spaced from one another and arranged to align with the openings which extend through the double

tapered hangers

42 and 44. In the upper end of these openings or passages 68 and 70, there are elon gated outwardly flaring seats 72 and 74, which are adapted to receive

conical sealing members

76 and 78, of a design hereinafter. described, these sealing members being made of hard metal or the like, and having interior bores 80 which are equal to or larger than the interior diameter of the

tubing strings

50 and 52.

Mounted on the cap 58, is a dual completion manifold 82 provided with

vertical passages

84 and 86 arranged for alignment with the passages 68 and in the cap 58. The

passages

84 and 86 have

side outlets

88 and 90, which are adapted to receive valves, or to be plugged, as is well known in the art, it being understood that when provided with valves, the installation will permit simultaneous flowing of the well from the

tubing strings

50 and 52.

The manifold 82 is provided with elongated outwardly and downwardly tapering

conical surfaces

92 and 94, correspondingly reversely with the surfaces 72 and 74 in the cap 58, and the manifold has a bottom flange 96 which may be bolted or otherwise suitably secured to the top surface of cap 58. A plurality of circularly spaced studs 98, with their corresponding nuts, are shown for this purpose.

When the manifold 82 is mounted on the cap 58, the

by the series of securing bolts 98, and in so doing the.

' lips of the sealing cones 'are flexed inwardly into close sealing contact with the

tapered surfaces

72, 74, 92 and 94. These surfaces, and the exterior tapered surfaces of the sealing cones, are so designed and machined, that effective metal to metal sealing contact will result through- Patented Sept. 26, 1961 out the vertical length of the exterior surfaces of the lips, when the flange 96 contacts the upper face of the cap 58. At this time, sealing energy will be stored in the lips of the cones, and though they will be flexed inwardly, they will not be distorted to an extent such as to reduce the full bore 89 through these cones. It will be noted that there are no shoulders in the

tapered surfaces

72, 74, 92 and 94, whereby it is not possible for the parts to contact the ends of the sealing cones, and to crush same. The manifold 82 has an upper flange 100 which may be bolted to a flange 102 of any appropriate top part '104, there being sealing cones 107 and 109 disposed between these parts, and in the manner previously described, with regard to the

sealing cones

76 and 78, if desired. The top part 104 has corresponding passages 106 and 108 extending therethrough to permit flow through these passages if necessary. The top part '104 may be suitably constructed in the manner not shown, but as indicated by the interior threading, at 111 to receive

removable closure plugs

112 and 114 or back pressure valves, or the like, which would be arranged to close the top of the passages against escape of pressure.

With this arrangement, the well may be simultaneously flowed from the

tubing strings

50 and 52, through the

side outlets

88 and 90 of the manifold 82, under control of suitable valves (not shown) on the

outlets

88 and 90. The various parts described form effective seals against escape of fluid under pressure. The construction is such that the overall height of the wellhead is reduced, while providing for simultaneous flow from the separate strings of tubing.

FIGURE 2 is a fragmentary vertical section view showing the manner in which the top lip 110 of one of the double tape-red hangers 42 is sealed against the conical Surface 69 of the tubing head cap 58. In this figure, the outer and upwardly extending tapered surface 116 of the hanger 42 is shown to be of slightly steeper taper than the surface 69 which it is adapted to engage. When the parts are initially assembled, before setting up the bolts between the tubing head flange and the tubing head top, the surface 116 contacts the surface 69 at about the point 118, and below this point, the surfaces diverge slightly from one another. When the connecting bolts are set up, to draw the tubing head top 58 downwardly toward contact with the tubing head flange, the lip 110 of the hanger is flexed slightly inwardly and within the elastic limits of the metal, until the

surfaces

116 and 69 are in parallel relationship with one another, and in tight contact with one another, these surfaces being suit-ably machined to make a tight metal to metal contact. The hydraulic packing ring shown in the surface 116 will be compressed into its groove when the parts are brought together into metal to metal sealing engagement with one another, thus insuring a pressure-tight seal between the surfaces with sealing energy thereby stored in the flexible lip 110, which has a tendency to resume its normal position as is shown in FIGURE 3. In addition, the pressure of fluid within the interior of the hanger, acts to constantly force the lip 110 outwardly into tight sealing engagement with the surface 69. With this arrangement tight seals are insured between the upper lip of the hanger and the tubing head top 58, between the lower lip of the double tapered hanger and the interior sealing surface of the larger hanger bushing, as well as between the outer tapered surface of the larger hanger bushing and the interior seat and bowl of the tubing head, at the time the cap 58 is brought into tight sealing engagement with the A.P.I. ring gasket on the flange of the tubing head.

FIGURE 3 is a fragmentary vertical sectional view intended to show the relationship of the parts prior to the time when the studs are tightened to draw the lower flange 9% of the manifold 82 downwardly into contact with the top surface of the tubing head cap 58, in order to form a seal with the upper and lower lips of the sealing cone 76. The sealing cone has an upper flexible lip 118 and a lower flexible lip 120, and these lips are adapted to engage

conical surfaces

122 and 124 in the

parts

96 and 58. As previously described in connection with FIGURE 2, the

outer surfaces

126 and 128 of the lips of the sealing cones are of a slightly steeper taper than the

surfaces

122 and 124, so that prior to the time when the supporting parts are pulled together by the studs, these surfaces contact the lips at points adjacent to the upper ends of the

surfaces

126 and 128. The hard metal cone 76 is so designed, and is of such material, that the lips 118 and thereof may flex slightly inwardly (within the elastic limits of the metal) when the connecting parts are drawn toward one another, until the

surfaces

126 and 128 are parallel with and in intimate contact with the

surfaces

122 and 124, and at the time the meeting edges of the

parts

96 and 58 contact one another. By reason of the fact that there are no shoulders in the

surfaces

122 and 124, the connecting parts can be drawn together in contact with one another without the exertion of any crushing forces on the upper and lower ends of the lips of the sealing cone, and the design and machining are such that intimate contact is secured at the time the connecting parts abut one another, yet without reducing the full bore provided through the sealing cone. The material of the sealing cone is such that energy is stored in the lips when they are thus flexed, their tendency to resume the position of FIGURE 3 contributing to the effectiveness of the sealing engagement of the tapered surfaces. In addition, fluid under pressure within the system, acting against the lips of the sealing cone, tends to maintain the seal.

We claim:

1. In apparatus for multiple completion of wells, at tubing head of size to receive and support a plurality of strings of flow tubing, said tubing head having a hanger seat therein, a hanger bushing supported in said seat and having exterior means to form a seal therewith, said hanger bushing having a plurality of separate passages extending vertically therethrough, said passages having smaller hanger seats formed therein, a unitary smaller tubular hanger bushing for each of the tubing strings suspended and sealed in the seats formed in said passages, said smaller hangers having means to connect with the upper ends of the strings of tubing to support and seal same in said tubing head, a tubing head top element secured on and above said tubing head, said top element having vertical passages and sockets with inwardly tapered walls therein in alignment with said smaller hanger seats, and said smaller hangers being provided with upwardly extending flexible lips having exterior sealing surfaces of a taper slightly steeper than the taper of said sockets, said tubing head being provided with means for drawing said top element toward said tubing head to inwardly flex said lips of said smaller hangers into sealing engagement with the walls of said sockets.

2. Apparatus as defined in claim 1 wherein said plurality of passages are arranged symmetrically about the axis of said first-mentioned hanger bushing.

3. Apparatus as defined in claim 1 wherein said smaller tubular hanger bushings in their position suspended in said first-mentioned hanger bushing contact the inner wall surface of said first-mentioned hanger bushing only at the seat thereof.

4. Apparatus as defined in claim 1 including a second flow head element secured on and above said top element, said flow head element having vertical passages and sockets with inwardly tapering walls therein in alignment with the vertical passages in said top element, the upper ends of vertical passages in said top element having sockets with inwardly tapering walls therein, a unitary sealing bushing of metal or the like disposed between said elements in each pair of adjacent sockets thereof, each of said sealing bushings comprising a relatively thick center section and oppositely directed tubular portions constructed to yield inwardly and which have outer surfaces which taper inwardly toward the respective ends of said sealing bushing and are adapted to engage with and seal in the associated sockets of said elements, the lengths of said outer surfaces being substantially shorter than the lengths of the walls of the associated sockets and the taper of said outer surfaces being slightly steeper than that of the walls of the asso ciated sockets, said elements having connecting flanges presented toward one another and means for drawing said elements toward one aonther until their flanges are in contact so as to bend said tubular portions inwardly until their outer surfaces are in fluid pressure-tight contact with the tapering walls of the associated sockets,

said bushing having a bore therethroughin alignment with and of a diameter at least as large as that of the associated passages when said flanges contact one another.

References Cited in the file of this patent UNITED STATES PATENTS