US3656763A

US3656763A - Sealing packer

Info

Publication number: US3656763A
Application number: US51955A
Authority: US
Inventors: Philippe Joubert; Andre Castela
Original assignee: IFP Energies Nouvelles IFPEN
Current assignee: IFP Energies Nouvelles IFPEN
Priority date: 1969-07-07
Filing date: 1970-07-02
Publication date: 1972-04-18
Anticipated expiration: 1989-04-18
Also published as: ES187842Y; JPS5027001B1; FR2052030A5; DE2033645A1; NL7009997A; SE352155B; CA926854A; SU401799A3; ES187842U; GB1270056A; RO56563A

Abstract

Sealing packer formed of two sealing assemblies movable between a joining position and a spaced position, each assembly comprising two lateral straight packing members on both sides of a semi-circular central packing member, said lateral and central packing members being adapted to be displaced together to a position of abutment of the lateral packing members of an assembly against those of the other assembly, first compressible elastic means connecting a support of said lateral packing members to the driving means of said central packing members, to provide for the relative displacement of the central packing member with respect to the lateral packing members, and second compressible elastic means interposed between said central packing member and said driving means, to provide a compression stress on said central packing members in their joining position.

Description

lUite States Patent .loubert et a1.

[15] 3,656,763 [451 Apr. 18,1972

[541 SEALING PACKER [72] Inventors: Philippe Joubert, Rungis; Andre Castela,

Mesnil Le Roi, both of France [73] Assignee: lnstitut Francais Du Petrole, Des Carburants Et Lubriiiants, Rueil Malmaison (Hauts de Seine), France [22] Filed: July 2, 1971) [21] Appl.No.: 51,955

[30] Foreign Application Priority Data July 7, 1969 France ..'.....6923038 [52] U.S.Cl ..277/63,277/129,251/l [51] lnt.Cl ..F16j 15/00 [58] Field ofSearch ..277/63, 126, 127, 129; 251/1 [56] References Cited UNITED STATES PATENTS 3,434,729 3/1969 Shaffer et a1 ..251/1 3,399,901 9/1968 Crow et a1. ..277/129 3,116,930 l/1964 Golden ..277/66 19 2o 25 30 l I -L 12 Q 12a Tl a x is i .ci is l 1B o 4 3 Primary Examiner-Samuel B. Rothberg Attorney-Craig, Antonelli & Hill [5 7] ABSTRACT Sealing packer formed of two sealing assemblies movable between a joining position and a spaced position, each assembly comprising two lateral straight packing members on both sides of a semi-circular central packing member, said lateral and central packing members being adapted to be displaced together to a position of abutment of the lateral packing members of an assembly against those of the other assembly, first compressible elastic means connecting a support of said lateral packing members to the driving means of said central packing members, to provide for the relative displacement of the central packing member with respect to the lateral packing members, and second compressible elastic means interposed between said central packing member and said driving means, to provide a compression stress on said central packing members in their joining position.

9 Claims, 6 Drawing Figures PATENTEmPR 181912 SHEET 1 BF 4 FIG] IN V E NTO R5 PH'IUPPE 3OUBERT and A roRnE Y s PATERTEUAPR 1a 1912 SHEET 2 BF 4 FIG .2

mvem'o RS PmuPPs 3000s RT and Auok CASTELA BY QaJ- QMhKJQJwW ATI'ORNEYS PATENTEDAPR 18 I972 SHEET U 0F 4 FIG.4C

IN VENTORS PHILIPPE IOUDERTAMI ANDRE CA $TE LA BY ormia maiovww P Hill AITORNEYS SEALING PACKJER This invention relates to a sealing packer useful in particular in a wellhead equipment, and is more particularly concerned with a sealing packer of the type comprising tubing packing members which can be displaced by translation.

For example, during a drilling operation, a drill pipe, formed of a drill string or of a flexible line, has to be directly introduced through a wellhead. This introduction of the drill pipe must be carried out under sealed conditions, especially in the case of off-shore drilling so as to avoid any disturbance in the mud circulation circuit.

According to the prior art, the sealing about the drill pipe may be achieved by deformation of a wall of an annular chamber surrounding the drill pipe.

Such devices provide for a convenient sealing but the high friction forces developed between said wall and the drill pipe, make them highly power consuming and result in a rapid wear requiring a frequent replacement of the sealing means. Such replacement operations become longer and more expensive as the immersion depth of the wellhead is increased.

Other devices can be used whereby two members, carrying packing means, having an .0 -shaped cross-section, are joined together so as to enclose the drill pipe. These devices provide for a good sealing but their working life is reduced by the wear and deformation of the packing means in their central portion in contact with the wall of the drill pipe. This wear depends mainly on the condition of the drill external surface. A rapid and substantial wear has been observed on the packing members of the sealing packer of a drill pipe formed of rigid stems whose section has undergone deformations, or of a drill string formed of a flexible pipe.

it is an object of this invention tioned drawbacks.

Another object of the invention is to provide a sealing packer of the mentioned type whereby provision is made for an automatic compensation of the clearance resulting from the wear of the packing members thereby providing a substantially increased period of use of the sealing packer.

Still another object of the invention is to produce a sealing packer providing for a good sealing about a movable column such as a drilling column, in spite of deformations of the external surface of said column.

A further object of the invention is to produce a sealing packer specially adapted to provide for a good sealing about a drilling column formed of a flexible pipe.

These objects are achieved, according to this invention, by a sealing packer providing for the sealing about an elongated element passing through said packer, comprising at least two sealing members placed respectively on opposite sides of the longitudinal axis of the element, at the same level thereof, each of which comprises a central packing member carried on a first support member and two lateral packing members, separate from said central packing member, both carried on a second support member said central packing members of said sealing members being adapted to contact, in their joining position, said elongated element over the whole periphery of a section thereof, the fluid leakage through the edges of the contact zones between said packing members, in said joining position, being prevented by said lateral packing members whose contact zones are in the extension of those of the central packing members, said sealing packer comprising means for displacing the assemblies of said packing members in opposite directions with respect to each other between a position of maximum spacing and a position of abutment of said lateral packing members against each other, and means for ensuring a relative displacement of said central packing members with respect to said lateral packing members in abutment position.

Said means for ensuring said relative displacement may consist of first elastic means connecting said second support member to said means for displacing the assembly of said packing members on which is secured said first support member.

Said first support member may be secured to said means for displacing the assembly of packing members through second to avoid the above-menelastic means subjected to a precompression in the joining position of the central packing members so as to ensure that a sufiicient pressure is exerted by the central packing member on the elongated element in spite of changes in the cross-section thereof in the course of its displacement and of the wear of said central packing members.

The invention will be better understood and further advantages thereof will be made apparent from the following description of a non-limitative embodiment of the invention, given with reference to the accompanying drawings wherein:

FIG. 1 diagrammatically illustrates an example of use of a sealing packer according to the invention,

FIG. 2 shows an axial cross-section of an embodiment of sealing packer according to the invention,

FIG. 3 is a partial view from above along line AA of FIG. 2,

FIGS. 4 A to 4 C diagrammatically illustrate one way of operating the sealing packer shown in FIGS. 2 and 3.

Referring FIG. 1, reference numeral 1 shows an immersed well head on the sea bottom 2. A drilling column 3, e.g. a flexible drill-pipe, passes through the wellhead 1. During the drilling operations a circulation of muds is performed, said muds entering the well 4 through the inside of flexible pipe 3, being recovered and conveyed to the drilling platform as usual through duct 5. In order to ensure a normal circulation of the muds along the path indicated by the arrows of FIG. 1, there is provided a sealing packer 6 providing for the sealing about the flexible pipe 3 at the top of the wellhead 1.

A preferred embodiment of sealing packer according to the invention is shown in FIG. 2. This sealing packer is provided with a body 7. Clamps 8 ensure the centering and fastening of the sealing packer onto the wellhead 1.

This fastening is achieved by known assembling means, such as, for example bolts, whereas joints (not shown) ensure the sealing between the wellhead 1 and the body 7 of the sealing packer.

The upper part of the sealing packer is provided with an orifice 9 for the introduction of a drilling column such as flexible pipe 3 into the wellhead. This orifice 9 may be surmounted with a device such as a guiding cone for facilitating the introduction of the flexible pipe. Two opposite slide members 10 guide the packing members to their joining position as explained below.

FIG. 3 is a partial cross-sectional view from above along line AA of FIG. 2, illustrating sealing devices sliding inside the slide members 10.

A central packing member 11 ensures the sealing about the flexible pipe 3 over substantially one half of its cross section. Lateral packing members 12 ensure the sealing along a diametral plane of the pipe at both ends 11a and 11b of the central packing member 11. A semi-circular packing member 13 ensures the sealing below the level of the

packing members

11 and 12, in a plane perpendicular to the axis of the flexible pipe 3.

The packing members 12 are fastened, for example by sticking, to an element 14 which is guided during its displacements, by the slide 10. The element 14 is connected through elastic means 15 to a pressing member 16 actuated by the stem of a jack, not shown.

The central packing member 11 is provided with two inclined end surfaces 18 for ensuring the sealing between the

packing members

11 and 12 is fastened, for example by sticking, onto two rigid remote members 19 secured by screwing onto a support member 20 connected to a pressing piston 21 through elastic means 25. Piston 21 is made integral with member 16 through a rod 22 slidably mounted in a bore 23 of element 14.

As shown in FIG. 2, the element 14 forms a casing wherein the central packing member 11 can be displaced. A cover 24 (FIG. 2) co-operating with the element 14, prevents any deformation of the central packing member in a direction parallel to the pipe axis. The packing member 13 is held against a shoulder 26 of cover 24 by means of a plate 27. This packing member ensures the sealing in a plane perpendicular to the axis of the flexible pipe 3 over an annular surface 28.

The elastic means and 25 may consist of compression springs or elastic rings, for example rubber rings, and their compression strokes are limited towards the right-hand side of FIG. 3, by means of

stop members

29 and 30 respectively, so arranged that the displacement D of the pressing member 16 with respect to element 14 is larger than the displacement d of the pressing piston 21 with respect to the support member during the step of drawing aside or joining together both halves, for the above-mentioned reasons.

The

packing members

11, 12, 13 are made of a material which must exhibit good mechanical performances with respect to the tearing and bending strengths as well as a good resistance to sea water and hydrocarbons.

FIGS. 4 A to 4 C diagrammatically illustrate the working of the above-described sealing packer.

FIG. 4 A shows the

packing members

11, 12, 13 in their spaced position giving passage to the pipe 3 along the axis of the wellhead. Hydraulic jacks, not shown in the figure and remotely controlled from the surface installation, or any other pressuring device, bring the packing members closer to each other through the intermediary of the rods 17 secured onto the pressing members 16.

As shown in FIG. 4 B, the packing members 12 then become effective in their sealing action in a diametral plane By increasing the pressing stress until a convenient stroke of D-d is achieved by compression of elastic means 15, the central packing member 11 comes into contact with the external surface of pipe 3 as shown in solid line in FIG. 4 C.

By further increasing the pressing stress the elastic means are compressed in turn over a stroke d, thereby imparting to the central packing member 11 the compression stress required for ensuring the sealing about pipe 3, as illustrated in dashed line in FIG. 4 C. In order to impart to the central packing member 11 a sufficient compression stress the compressibility of elastic means 15 is chosen to be greater than that of elastic means 25.

As shown in FIG. 3, the central packing member 11 being held only at its two end parts through members 19, said packing member is capable of undergoing substantial deformations in order to ensure the sealing at any point about the periphery of pipe 3.

In the case of substantial variations of the pipe external diameter, the elastic means absorb these variations whereby the pressing stress imparted by the central packing member onto the pipe 3 is maintained at a substantially constant value. Moreover the elastic means 25 automatically compensates for the clearance resulting from the wear of the central packing member 11, thereby increasing the workinglife of the sealing packer while keeping the advantage of a perfect sealing.

When opening the sealing packer and for avoiding any deformation of the

rims

12a and 12b of the packing member, so as to prevent any casual buttressing of said rims against those of the other half portion of the sealing packer during closure thereof, it is convenient to first draw the packing member 11 apart from the pipe, this being achieved by giving to elastic means 15 a compression stroke D greater than that d" of elastic means 25.

By control of the jacks, the pressing member 16 is drawn apart from its position shown in dashed line in FIG. 4 C, said member driving therewith piston 21 until the same comes into contract with the stop members 30, after a displacement d," in the position shown in solid line in FIG. 4 C. The displacement is continued until the pressing member 16 comes into contact with stop members 29, after a displacement D, resulting in the withdrawal of the packing member 11, as shown in FIG. 4 B, followed with the opening of the sealing packer in the position diagrammatically illustrated in FIG. 4 A.

It is apparent from the above description of the sealing packer, that only the central packing member 11, in contact with pipe 3 is subjected to wear. This packing member can be replaced when completely worn. For this purpose the slide members 10 are closed at their ends by detachable covers 31 (FIG. 2) and by use of any known device, the assembly of the members provided with packing means may be withdrawn, said withdrawal being optionally performed by means of control jacks.

We claim:

1. A sealing packer providing for the sealing about an elongated element passing through said packer, comprising at least two sealing members placed respectively on opposite sides of the longitudinal axis of the element, at the same level thereof, each of which comprises an assembly of packing members including a central packing member carried on a first support member and two lateral packing members, separate from said central packing member, both carried on a second support member, said central packing members being adapted to contact, in their joining position, said elongated element over the whole periphery of a section thereof, the fluid leakage through the edges of the contact zones between said packing members, in said joining position, being prevented by said lateral packing members whose contact zones are in the extension of those of the central packing members, said sealing packer comprising means for displacing the assemblies of said packing members in opposite directions with respect to each other between a position of maximum spacing and a position of abutment of said lateral packing members against each other, and means for ensuring a relative displacement of said central packing members with respect to said lateral packing members in abutment position.

2. A sealing packer according to claim 1 wherein the first support member is secured to said means for displacing the assemblies of said packing members and said means for relative displacement are formed of first elastic means connecting said second support member to said means for displacing the assemblies of packing members.

3. A sealing packer according to claim 1, wherein said first support member of the central packing member is secured to said means for displacing the assemblies of packing members through second elastic means subjected to a precompression stress: in the joining position of the central packing members and ensuring the maintenance of a sufficient compression stress on the elongated element through the central packing members, in spite of cross-section variations of the portion of said element passing through the sealing packer and of the degree of wear of said central packing members.

4. A sealing packer according to claim 1, wherein said central packing member is fastened, at said level, only by its two end parts, to said first support member, so that the central packing member can better follow the outline of the section of the elongated element.

5. A sealing packer according to claim 2, wherein said first elastic means have a higher elastical deformation coefiicient than that of said second elastic means.

6. A sealing packer according to claim 1 wherein the two lateral packing members form two rims which, in the joining position of the central packing members, press against the edges of the contact zones thereof.

7. A sealing packer according to claim 1, wherein said means for displacing each assembly of packing members comprises a lateral displacement rod, the displacement stroke of which relative to each support member is limited by stop members in the direction of the moving apart of said members, the displacement stroke relative to the first support member being less than the displacement stroke relative to said second support member.

8. Sealing packer formed of two sealing assemblies movable between a joining position and a spaced position, each assembly comprising two lateral straight packing members on both sides of a semi-circular central packing member, driving means for displacing said central packing member, said lateral and central packing members being adapted to be displaced together to a position of abutment of the lateral packing members of an assembly against those of the other assembly, first compressible elastic means connecting a support of said lateral packing members to the driving means of said central packing members, to provide for the relative displacement of the central packing member with respect to the lateral packing members, and second compressible elastic means interposed between said central packing member and said driving means, to provide a compression stress on said central packing members in their joining position. 5

9. A sealing packer according to claim 3, wherein said first elastic means have a higher elastical deformation coefficient than that of said second elastic means.

Claims

5. A sealing packer according to claim 2, wherein said first elastic means have a higher elastical deformation coefficient than that of said second elastic means.

8. Sealing packer formed of two sealing assemblies movable between a joining position and a spaced position, each assembly comprising two lateral straight packing members on both sides of a semi-circular central packing member, driving means for displacing said central packing member, said lateral and central packing members being adapted to be displaced together to a position of abutment of the lateral packing members of an assembly against those of the other assembly, first compressible elastic means connecting a support of said lateral packing members to the driving means of said central packing members, to provide for the relative displacement of the central packing member with respect to the lateral packing members, and second compressible elastic means interposed between said central packing member and said driving means, to provide a compression stress on said central packing members in their joining position.