Multiple-section Well Blowout Preventer Packer

Abstract

The disclosure concerns a well blowout preventer packer that includes multiple elastomer body sections formed to be arranged in side-by-side circular series relation for coaction to seal off a well in response to simultaneous constriction.

Description

BACKGROUND OF THE INVENTION

This invention relates generally to well blowout prevention, and more particularly concerns improvements in constrictable packers used in such prevention to reduce, or close, well openings.

For safety reasons, well blowout preventers have come to be considered as extremely useful and necessary during drilling operations where gas under pressure is present, or likely to develop, in the well being drilled. In particular, preventers as described in U.S. Pat. No. 2,609,836 to G. S. Knox have been highly successful in such use. Such equipment incorporates a packer unit which is an annulus of radially contractable material incorporating a metallic armature or core, the packet being controllably closable about a well pipe or other equipment to seal off the well.

While such packers are of great advantage and utility, their heavy weight necessitates the use of special lifting equipment during their installation or replacement in preventer housings. Also, the molding of such annular packers about the complete armature is found to be time consuming, expensive and intricate, as necessitated by the required reliability of the packer in use. For example, the rubber is subjected to extreme extrusion during packer constriction, and unless properly molded and bonded to the steel armature the rubber could fail with consequent loss of the well. Accordingly, there is need for a packer unit that is relatively easily and inexpensively moldable, (especially during the development phase) and which can be easily handled in the field.

BRIEF SUMMARY OF THE INVENTION

It is a major object of the invention to provide solutions to the above as well as other problems encountered in respect of blowout preventer packer units. Basically, the invention is embodied in a packer comprised of multiple elastomer body sections adapted to be arranged in side-by-side circular series relation to define a central opening, the sections having outwardly presented faces to receive constricting force transmission, and inwardly presented faces inwardly deformable to reduce the size of the central opening in response to such force transmission; and the sections each having opposite side faces through which compressive force is transmitted between the sections when they are arranged in circular series to transmit constricting force. As will appear, the side faces of each section typically extend in generally axial radial planes, and with taper toward the central axis, whereby a predetermined number of such sections may be individually assembled into a packer ring in a blowout preventer. The resultant ring or annulus will then function in the same manner as an integral annulus as respects sealing off a well, as described in the above referred to Knox patent. Further, the wedge-shaped body sections are capable of molding with far less involvement of intricacy.

It is another object of the invention to provide in each of the above-referred-to body sections at least one rigid anchor member extending therein for holding or anchoring the elastomer material during its extreme extrusion during well sealoff. If, for example, four quadrant-shaped sections are to be provided, then each would contain at least two or three of the anchor members. Typically, the anchor members in adjacent sections will be everywhere spaced apart, whereby the sections will abut one another at their elastomer side faces which transmit loading and extrude during constriction.

It is yet another object to provide the sections with interfitting shoulders proximate the side faces to interlock the sections in correct position during their assembly. As an example, the shoulders may be defined by tongue-and-groove elements as will be described.

Finally, the invention contemplates a method of forming such a packer, including providing the sections as described, arranging sufficient of the sections in a circular pattern to define an annulus and supporting the annulus in a blowout preventer for reception of constricting force.

These and other objects and advantages of the invention, as well as the details of illustrative embodiments, will be more fully understood from the following detailed description of the drawings, in which:

DRAWING DESCRIPTION

FIG. 1 is an elevation take in section showing the multiple-section packer of the invention installed in a blowout preventer;

FIG. 2 is a fragmentary plan view showing of several preventer sections assembled together in an annular packer, and broken away to show interior construction;

FIG. 3 is a section taken on line 3-3 of FIG. 2;

FIG. 4 is a section taken on line 4-4 of FIG. 3

FIG. 5 is a fragmentary elevation illustrating deformation of a body section of the invention into sealing engagement with a pipe or other tubular element in a well;

FIG. 6 is an enlarged fragmentary elevation illustrating assembly of multiple sections into a packer annulus;

FIG. 7 and 8 are top and bottom plan views respectively of the body section seen in FIG. 6, and

FIG. 9 illustrates a modified body section.

DESCRIPTION OF PREFERRED EMBODIMENTS

Reference is first made to FIG. 1 showing a typical blowout prevention assembly 10 in which the invention is usable. The assembly includes a body or housing member 11, having concentric cylindrical surfaces 12, 13, 14 and 15 of progressively increasingly diameter, and associated with body annular sections 16--18. A cap 19 is releasably held to the outer and upper section 18 as by a split ring 20 overlying the cap shoulder 21 and received in annular groove 22 found in the body. The cap seats against a body shoulder 23 and fasteners 20a hold the ring 20 to the cap. A cylindrical section 24 of the cap forms a bore 25 through which tubular goods such as well casing 26 or pipe is run vertically.

The assembly 10 also includes a packer actuator 30, which has a lower piston portion 31 having piston fit between surfaces 13 and 14, with suitable annular seal rings 32 and 33 carried as shown. An actuator sleeve portion 34 pilots or guides against body cylindrical surface 13 as the actuator strokes vertically during constriction and release of the packer assembly to be described. In this regard, fluid pressure may be applied as from a source 35 and via porting 36 to the underside of the piston portion 31 to raise the actuator 30, the latter being free to drop upon release of such applied pressure.

The body 11 is also shown as supported on a stack of equipment which may include an annular member 38 having side outlet ports 39 through which pressure flow from the well may be diverted upon operation of the blowout preventer to seal off about casing 26 or other pipe, or otherwise to seal off the opening through the preventer when no such piping is present.

The packer assembly 40, as also illustrated in FIGS. 2--8, comprises a circular series of wedge-shaped elastomer body sections 41 defining a central opening 42 and having outwardly presented faces 43 to receive constricting force application or transmission, and inwardly presented faces 44 which are inwardly deformable to reduce the size of the opening 42 in response to such force transmissions. Such force transmission by the conical portion 45 of the actuator is better seen in FIG. 5, the actuator having an outer terminal 45a which guides against body surface 15 as the actuator moves upwardly. Note in FIG. 5 that the extreme inner surfaces 44 of the sections are in engagement with the casing 26 to effect the seal. In this regard, and as will appear, the inner surfaces 44a of the sections which are identified in FIG. 2 will also come into sealing engagement with the casing as the elastomer or rubber material extends inwardly in response to constricting force transmission, whereby a tight annular packoff is effected against the casing or pipe. In the absence of the latter, the open hole may be tightly closed by extreme inward extrusion of the elastomer, to prevent a well blowout.

In this regard, well pressure may communicate freely between the packer and the actuator portion 45, as via the openings 46 between the outer extremities of adjacent body sections 41 better seen in FIG. 2. Such pressure exerted downwardly on the actuator cone 45 is counteracted by the pressure from source 35 to move the actuator upwardly.

It is an important feature of the invention that the sections 41 each have opposite side faces 50 and 51 through which compressive force is transmitted (as indicated by arrows 52 and 53 in FIG. 2) between the sections during constricting force transmission by the sections as described. In this regard, the individual sections then coact to seal off at their interfaces 50 and 51, blocking escape of well pressure fluid; further, such coaction results in extrusion the elastomer including the interfaces and sealing off of the well in a manner similar to that described in U.S. Pat. No. 2,609,836, where an integral elastomer annulus is utilized. On the other hand, the individual sections 41 may be molded with much simpler equipment, and then cemented together before installing into the assembly 10. For this purpose, rubber cement may be used.

The sections 41 are further characterized in their illustrated form, as having side faces 50 and 51 which extend in generally axial radial planes, i.e. with taper toward the central axis 53.

It is a further feature of the invention that the sections 41 may have interfitting shoulders proximate the side faces, which facilitate assembly of the sections into an annular packer for placement into the blowout preventer housing. In the illustrations, the shoulders are defined by a cylindrical protrusion or boss 57 at side face 51 of one section, and a recess 58 sunk in side face 50 of the adjacent section, the protrusion received in and fitting the recess. Such interfitting may be carried out outside the housing 11, as for example on a dished form 59 as seen in FIG. 6, whereby a complete packer with interfitting sections 41 may be assembled and supported at surface 60. Thereafter, the packer may be lifted into the preventer housing, as by means of fasteners 61 received downwardly into threaded openings 62 in the anchor structure of certain sections 41, as seen in FIG. 3.

A further feature concerns the provision of rigid anchor members extending in the sections, as for example in the manner to be described, in order to retain the elastomer material against well pressure induced upward extrusion out of the preventer assembly. The illustrated anchor members 64 in adjacent sections are seen to be everywhere spaced apart, i.e. typically spaced from the planes defined by the interfaces 50 and 51, to allow inward extrusion of the elastomer material proximate those faces. In this regard the interfitting of the sections as at bosses 57 and recesses 58 tend to prevent radial slippage of one section relative to another during inward and outward bodily travel of the sections as controlled by the actuator. Also, such interfitting makes proper alignment of the sections for cementing purposes much easier.

Each anchor member 64, in the illustrations, includes upper and lower metal plates 65 and 66 which extend generally horizontally, and ribbing 67 interconnecting the plates and extending within the section elastomer material 69 in spaced relation to the side faces 50 and 51. Small bosses 68 project from the ribbing 67 and into the elastomer for anchoring the latter to the ribbing during extrusion. Note that the material 69 loops about, and is bonded to, the ribbing, as for example at 70 and 71, so that it remains anchored thereto under all extrusion conditions. Referring back to FIG. 1, the plates 65 and 66 are respectively confined between the cap underside 72 and the upper terminal 27 of the housing member 16, during inward and outward travel of the sections 41.

Referring now to FIG. 9, it illustrates an elastomer body section 41a of somewhat different configuration, in that the annular dimension between side faces 50a and 51a is substantially greater than characteristic of section 41 as seen in FIG. FIG. 7. Also, it contains three anchor members 64a as shown, these being spaced apart and having a construction similar to those described at 64 FIGS. FIGS. 2 and 3.

Claims

I claim:

1. In a well blowout preventer, the combination comprising:

a circular series of elastomer body sections defining a central opening and having outwardly presented faces to receive constricting force transmission and inwardly presented faces inwardly deformable to reduce the size of said opening in response to said force transmission,

said sections each having opposite side faces through which compressive force is transmitted between the sections during said constricting force transmission, and there being interfitting shoulder means on adjacent sections for blocking relative displacement of said adjacent sections during inward deformation thereof in response to said constricting force transmission.

2. The combination of claim 1 including rigid anchor members extending in said sections.

3. The combination of claim 2 wherein the anchor members in adjacent sections are everywhere spaced apart.

4. The combination of claim 3 wherein said opening has a central vertical axis, and each anchor member comprises upper and lower plates and ribbing interconnecting the plates and extending within the body section in spaced relation to and approximately midway between the section opposite side faces.

5. The combination of claim 4 wherein said opposite side faces of each section taper toward said opening.

6. The combination of claim 2 including blowout preventer means carrying said sections for bodily movement toward and away from said opening.

7. The combination of claim 1 wherein said sections define a central axis and said side faces extend in generally axial radial planes.

8. The combination of claim 1 in which said shoulder means are defined by a protrusion at the side face of one section and a recess sunk in the side face of the adjacent section, said protrusion received in said recess.

9. In a well blowout preventer, the combination comprising:

a. a circular series of elastomer body sections defining a central opening and having outwardly presented faces to receive constricting force transmission and inwardly presented faces inwardly deformable to reduce the size of said opening in response to said force transmission, and

b. said sections each having opposite side faces through which compressive force is transmitted between the sections during said constricting force transmission,

c. the opposed faces of adjacent sections being bonded together.

10. The combination of claim 9 including interfitting shoulder means on the sections proximate the bonded together opposed faces of adjacent sections for blocking relative displacement of such adjacent sections during inward deformation thereof in response to said constricting force transmission.

11. The combination of claim 9 in which there is a rigid anchor member extending in each section between said inwardly and outwardly presented faces and approximately midway between said opposed side faces, each anchor member including upper and lower plates and ribbing interconnecting said plates and extending within each said section in spaced relation to said opposite sides thereof.