U.S. patent application number 11/264850 was filed with the patent office on 2006-03-23 for method for sealing radially expanded joints.
Invention is credited to D. Scott Costa, Richard W. DeLange, M. Edward Evans.
Application Number | 20060061099 11/264850 |
Document ID | / |
Family ID | 32228980 |
Filed Date | 2006-03-23 |
United States Patent
Application |
20060061099 |
Kind Code |
A1 |
Evans; M. Edward ; et
al. |
March 23, 2006 |
Method for sealing radially expanded joints
Abstract
Connectors and connections that enhance mechanical and sealing
engagement between the ends of tubular bodies that are radially
expanded by a forging tool. The connectors are designed to maintain
or restore mechanical and sealing engagement following expansion.
The connections are made by joining components that exhibit
different spring back characteristics following mechanical
deformation. Dissimilar material may be used for the connectors or
the connected components can be made of the same materials but
dimensioned and configured to exert an interfering force between
engaged components following expansion. In operation, a material or
component with a high spring back characteristic is positioned
adjacent a material or component having a lower spring back
characteristic. Following passage of a forging tool, the expanded
components spring back differently toward their original unexpanded
dimensions to produce the enhanced seal or mechanical engagement.
The materials of the end connectors are selected and positioned
such that a compressive or locking force is exerted between the
different component of the connectors due to the difference in the
spring back of the materials or components.
Inventors: |
Evans; M. Edward; (Spring,
TX) ; Costa; D. Scott; (Kingwood, TX) ;
DeLange; Richard W.; (Kingwood, TX) |
Correspondence
Address: |
Carlos A. Torres;Browning Bushman P.C.
Suite 1800
5718 Westhelmer
Houston
TX
77057-5771
US
|
Family ID: |
32228980 |
Appl. No.: |
11/264850 |
Filed: |
November 2, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10290003 |
Nov 7, 2002 |
|
|
|
11264850 |
Nov 2, 2005 |
|
|
|
Current U.S.
Class: |
285/334 |
Current CPC
Class: |
E21B 43/103 20130101;
E21B 43/106 20130101; E21B 17/042 20130101; F16L 13/168
20130101 |
Class at
Publication: |
285/334 |
International
Class: |
F16L 25/00 20060101
F16L025/00 |
Claims
1-59. (canceled)
60. A method for enhancing the connection between connected members
that are plastically deformed while connected to each other,
comprising: forming a first member to exhibit a first spring back
characteristic following plastic deformation, forming a second
member to exhibit a second spring back characteristic following
plastic deformation, connecting said first and second members, and
plastically deforming said first and second members while said
first and second members are connected together whereby a
differential in said first and second spring back characteristics
enhances the connection between said first and second members
following plastically deforming said first and second members.
61. A method as defined in claim 60, further comprising: forming
said first member into a first radially and axially extending
annular shape, forming said second member into a second radially
and axially extending annular shape, and placing said second member
at least partially radially within said first member before
plastically deforming said first and second members whereby the
spring back of said first and second members produces a compressive
force between said first and second members following plastically
deforming said first and second members.
62. A method as defined in claim 61, further comprising: forming
said first member into a first radially and axially extending
annular shape, forming said second member into a second radially
and axially extending annular shape, and placing said second member
adjacent said first member before plastically deforming said first
and second members whereby the spring back of said first and second
members produces compressive forces between said first and second
members following plastically deforming said first and second
members.
63. A method as defined in claim 60, further comprising: forming
said first member in the shape of a first internally threaded box,
forming said second member in the shape of a first externally
threaded pin, and threadedly advancing said first pin into said
first box while connecting said first and second members.
64. A method as defined in claim 61, further comprising: forming
said first member in the shape of an internally threaded coupling
having a first box and a second box at axial ends of said coupling,
forming a third member in the shape of a second externally threaded
pin, and connecting said first, second and third members by
threadedly advancing said first pin into said first box and said
second pin into said second box, and plastically deforming said
coupling and said first and second pins by expanding said first and
second pins radially outwardly into said coupling.
65. A method as defined in claim 63, further comprising: connecting
multiple pin and box members together to form a string of well
pipe, placing said string of well pipe into a wellbore, and
radially expanding said string of well pipe.
66. A method as defined in claim 60, wherein said first member is
formed of a metal that is different from a metal of said second
member whereby said second spring back characteristic is different
from said first spring back characteristic.
67. A method as defined in claim 60, wherein said first member is
formed in a physical shape that is different from a physical shape
of said second member whereby said second spring back
characteristic is different from said first spring back
characteristic.
68. A method as defined in claim 66, wherein: said first member is
formed as an internally threaded box of a tubular well casing, said
second member is formed as an externally threaded pin of a tubular
well casing, and said first and second members are connected by
threadedly engaging said pin and box.
69. A method as defined in claim 68, wherein: said first member is
formed as an internally threaded box of a tubular well casing, said
second member is formed as an externally threaded pin of a tubular
well casing, and said first and second members are connected by
threadedly engaging said pin and box.
70. A method for enhancing the connection between connected members
that are plastically deformed while connected with each other,
comprising: forming a first member to exhibit a first spring back
characteristic following plastic deformation, forming a second
member to exhibit a second spring back characteristic following
plastic deformation, forming a third member to exhibit a third
spring back characteristic following plastic deformation, said
third spring back characteristic being different from said first or
second, or both of said first and second spring back
characteristics, connecting together said first, second and third
members, and plastically deforming said first, second and third
members while said first, second and third members are connected
together to enhance the connection between said first and second
members.
71. A method as defined in claim 70, further comprising: forming
said first member into a first radially and axially extending
annular shape, forming said second member into a second radially
and axially extending shape, forming said third member into a third
radially and axially extending annular shape, and placing said
third member at least partially coaxially with, and radially
intermediate, said first and second members before plastically
deforming said first, second and third members whereby said third
spring back characteristic of said third member produces a
compressive force between said first and second members following
plastically deforming said first, second and third members.
72. A method as defined in claim 70, further comprising: forming
said first member into a first radially and axially extending
annular shape, forming said second member into a second radially
and axially extending shape, forming said third member into a third
radially and axially extending annular shape, and placing said
third member at least partially coaxially with, and radially
externally of, said first and second members before plastically
deforming said first, second and third members whereby said third
spring back characteristic of said third member produces a
compressive force between said first and second members following
plastically deforming said first, second and third members.
73. A method as defined in claim 70, further comprising: forming
said first member into a first radially and axially extending
annular shape, forming said second member into a second radially
and axially extending shape, forming said third member into a third
radially and axially extending annular shape, and placing said
third member at least partially coaxially with, and radially
intermediate of, said first and second members before plastically
deforming said first, second and third members whereby said third
spring back characteristic of said third member produces an axially
directed compressive force between said first and second members
following plastically deforming said first, second and third
members.
74. A method as defined in claim 70, further comprising: forming
said first member into a first radially and axially extending
annular shape, forming said second member into a second radially
and axially extending shape, forming said third member into a third
radially and axially extending annular shape, and placing said
third member at least partially coaxially with, and radially
intermediate of, said first and second members before plastically
deforming said first, second and third members whereby said third
spring back characteristic of said third member produces a radially
directed compressive force between said first and second members
following plastically deforming said first, second and third
members.
75. A method as defined in claim 74, further comprising: forming
said first member in the shape of a first internally threaded box,
forming said second member in the shape of a first externally
threaded pin, and threadedly advancing said first pin into said
first box during said placing of said second member with said first
member.
76. A method as defined in claim 75, further comprising: forming
said third member in the shape of an annular band with a greater
spring back characteristic than said first and second members, and
placing said third member adjacent said first member, at least
partially, coaxially with, and radially externally of, said first
and second members.
77. A method as defined in claim 75, further comprising: placing
multiple third members in the shape of annular bands at axially
spaced locations along said first member whereby the spring back of
said third members produces compressive forces at axially spaced
locations along the connection between said pin and box.
78. A method as defined in claim 77, further comprising: placing a
fourth member having a fourth spring back characteristic in an
annular seal area radially intermediate said pin and box whereby
said fourth spring back characteristic of said fourth member
produces an enhanced seal between said pin and box following
plastically deforming said first, second, third and fourth
members.
79. A method as defined in claim 77, further comprising: forming an
annular recess in one or both of said first and second members, and
inserting at least a portion of said fourth member into said recess
before said first, second, third and fourth members are plastically
deformed whereby said fourth member is extruded into a spacing
between said first and second members when said first, second,
third and fourth members are plastically deformed.
80. A method as defined in claim 79, wherein said fourth member is
formed with a cross-section shape having one of a trapezoid,
rectangle, T-shape, Z-shape, or oval.
81. A method as defined in claim 80, wherein said fourth member is
formed of multiple components to form said cross-section shape.
82. A method as defined in claim 75, further comprising forming
said third member in an axially extending sleeve.
83. A method as defined in claim 82, further comprising forming
said third member in a frustoconical sleeve.
84. A method as defined in claim 82, further comprising forming
said third member with annular recesses along radially inner and/or
outer surfaces of said sleeve.
85. A method as defined in claim 82, further comprising forming
said third member with an annular sleeve having an oval
cross-sectional wall.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to connectors used
to secure individual pipe sections together to form elongated pipe
strings. More particularly, the present invention relates to end
connectors used to secure together pipe sections that are connected
together and then radially expanded to increase the internal
openings through the string of connected pipe sections and
connectors.
[0003] 2. Prior Art Setting of the Invention
[0004] Conventional casing strings are made up of a series of
individual pipe sections secured together at their ends by threaded
connections. These sections are frequently referred to as "joints."
Typically, a joint of casing is approximately 40 feet in length and
has a threaded male "pin" connection at one end of the joint and a
threaded female "box" connection at the opposite joint end. Some
joints may have a pin at each end, with the box connection being
formed by a short coupling threaded onto one of the pin
connections. Some casing is made with the box connection integrally
formed as a part of the tube. These integral box connections may
have radially larger external dimensions than the external
dimensions of the pipe body, or they may be flush joint connections
in which the connection outside diameter ("OD") and the pipe OD are
the same size.
[0005] A new technique for casing well bores expands the well
casing pipe radially after a string of the pipe has been lowered
into a wellbore. The casing pipe is enlarged radially by moving an
oversized forging tool, or "pig," centrally through the pipe,
causing the pipe opening to expand radially beyond its original
radial dimensions. This technique allows subsequent strings of
casing sections of the same size as the originally run string, to
be lowered through the enlarged casing string sections and
thereafter be similarly expanded. The subsequently run sting is
radially expanded so that the well is cased from top to bottom by a
series of linked sections of casing having substantially the same
internal opening diameters. The procedure is explained in greater
detail in U.S. Pat. No. 5,348,095, assigned to Shell Oil Co.
[0006] The threaded engagement between a properly secured pin and
box connection in a conventional casing joint is effective in
maintaining a secure mechanical connection that holds the string
together and effectively seals the internal casing area from the
formation wellbore environment. When the casing string and
connection are enlarged radially, a conventional connection changes
dimensionally in a way that can prevent the engaged components of
the connection from properly engaging and sealing. The radial
expansion of a conventional connection may weaken or otherwise
damage the pin and box structure sufficiently to permit mechanical
separation or leakage between the pin and box.
[0007] Threaded connections for oil field use mainly rely on three
types of seals. These include metal-to-metal shouldering seals,
seals formed by interfering engaged threads and deformable seal
rings entrapped between connected components. All three seal types
can be disabled by the radial expansion of the tubular joint and
connection. In each case, following the expansion of the pin and
box, the radial forces and interference between the pin and box
members are adversely affected, causing the seals to fail.
[0008] Failure of seals is due in part to the fact that the
expanded pin and box components have a natural tendency to spring
back slightly after having been expanded by the pig. The axial end
of the expanded pin also has a natural tendency to spring back into
the internal diameter of the pipe when the pig is removed. When a
conventional pin and box connection is expanded, once the expanding
force is removed, the pin tends to return to its original
dimensions more so than does the box. The distortion can be so
great that the pin and box threads may disengage. The separation
and distortion following the expansion process compromises the
seals located between the pin and box allowing leakage to occur.
The spring back may also create an obstruction in the bore of the
pipe.
[0009] The sealing mechanism in many threaded pipe connections
results exclusively from the engagement of metal-to-meal sealing
surfaces in the pin and box. The engagement of these seal surfaces
closes the annular space between the pin and box to provide a
pressure seal. Radial expansion of the connection can distort or
displace the sealing surfaces and engaged forced of these
connections which will permit leakage through the annular
space.
[0010] Connectors that employ an elastomeric, annular seal ring
between the engaged surfaces of the pin and box are also subject to
leakage when the connection expands radially. The annular
elastomeric seal of conventional O-ring-sealed connectors is
usually carried in an annular groove formed in either the pin or
the box, or both. The seal of such a connection is formed when the
annular seal ring is initially compressed radially between the
fully engaged pin and box. Subsequent radial expansion of the
engaged connection changes the radial compression of the annular
seal ring, which in turn may permit leakage through the expanded
connection. The dimensional changes in the groove occurring during
the expansion process may also damage the annular seal ring,
increasing the probability of a leak.
[0011] Another problem associated with radial expansion of the pipe
connections is that conventional well pipe connections are
susceptible to splitting along the length of the box when the
connections are expanded radially. The expansion process
concentrates stresses of expansion in any thin wall sections
present at the ends of the connected pipe segments. The acceptable
tolerance for wall thickness in conventional connectors is
relatively large so that a conventional pin and box may have a
non-uniform thickness that includes relatively thin wall areas
without being considered defective. In this conventional connector,
however, the concentration of the stresses induced by radial
expansion of the connections may be sufficient to rupture or over
expand the thin section. The probability of a conventional
connector having an area with a relatively thin wall section in
either the box or the pin is too great to permit the use of such
connectors in pipe strings that are to be radially expanded.
SUMMARY OF THE INVENTION
[0012] Many materials that are plastically deformed exhibit a
degree of elasticity that tends to restore the material to its
original condition after the deforming force is removed. The
characteristic, sometimes termed the "spring back" of the material,
is employed in the present invention by using differing materials,
or different configurations of the same material, to form the
components of the end connectors for tubular well pipe sections
that are to be expanded radially outwardly from the central pipe
axis. The difference in the spring back characteristics of the
differing designs or material configurations is used to increase
the residual compressive forces between the components of the end
connectors once the expansion is completed to enhance the
mechanical interconnection and seal between the connectors. In some
forms of the invention, the difference in spring back
characteristic is exhibited as a difference in the amount of return
movement of adjacent and/or connected components following plastic
deformation of the components. The differential in return movement
creates a bearing pressure or resultant force between the connected
and/or adjacent components that enhances a sealing effect or a
mechanical engagement or locking effect. As used herein, the terms
"connected" or "adjacent" are not limited to directed physical
contact or touching, but are rather intended to include a
relationship in which one component may directly or indirectly
affect, or respond to, another component.
[0013] In one form of the invention, a coupling is constructed of a
material having a high spring back value and the engaged pin of the
pipe body is constructed of a material having a lesser spring back
value. The engaged pipe and coupling are radially expanded with a
central forging tool that passes internally through the pipe and
coupling. Following passage of the forging tool, the pipe and
coupling are left in an expanded, relaxed state with no external
expanding force being exerted on the components. In returning to
this relaxed state, the coupling will contract more than the pin of
the pipe that is received within the coupling, causing the coupling
to exert a compressive force on the pipe pin. The compressive force
induced by the coupling springing back against the pin in an amount
that is greater than the pin springing back enhances the seal and
mechanical engagement formed between the expanded pin and
coupling.
[0014] The effect may be used for conventional pin and box
connections made from materials with similar spring back
characteristics by providing encircling bands of a high spring back
characteristic at selected sealing locations along the external
surface of the box. Following expansion of the connection and
bands, the increased spring back of the bands applies a compressive
force to the box at critical pin sealing areas.
[0015] The effect is also used to provide a post expansion seal by
employing a high spring back material or configuration within the
overlapping area in a connection between a pin and box of
conventional materials. The increased spring back of the high
spring back member operates to enhance the seal between the pin and
box to maintain a seal following the expansion of the
connection.
[0016] The difference in spring back of one geometric form of a
given material relative to a second geometric form of the same
material is also used to form a connection that is enhanced as a
result of the different post expansion spring back in the two
forms.
[0017] From the foregoing it will be appreciated that a primary
object of the present invention is to provide a connector between
tubular members that will ensure the structural integrity and
sealing capability of the connector after the connector and tubular
members have been expanded radially to increase their internal
dimensions.
[0018] An important object of the present invention is to provide a
connection that uses the inherent spring back differences between
different materials, or the spring back differences between
different physical configurations of the same or similar materials,
to provide or restore the sealing and/or pre-load forces between
adjoined tubular connections after the connections have been
expanded radially.
[0019] It is an object of the present invention to provide a
connection between two tubular members that uses the inherent
spring back characteristics of the same metals configured in
different physical shapes to enhance the seal and mechanical
strength of a tubular connection following radial expansion of the
connection whereby the use of the same materials reduces the
possibility of producing damaging galvanic reaction in the
connection.
[0020] It is a general object of the present invention to use the
differing spring back characteristics of differing materials, or
different configurations of the same material, to enhance the
mechanical and sealing connection between connected components of
materials that have been dimensionally altered.
[0021] The foregoing objects, features and advantages of the
present invention, as well as others, will be more fully
appreciated and understood by reference to the following drawings,
specification and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a half sectional view schematically illustrating a
forging tool radially expanding a well string and connector of the
present invention in which the connector is formed by the
engagement of two pins mated through a central coupling and in
which the coupling has a greater spring back than the two pins;
[0023] FIG. 2 is a quarter sectional view illustrating a connector
of the present invention comprising a coupling with a two-step
thread securing two pipe pins in which the coupling has a greater
spring back than the two pins;
[0024] FIG. 3 is a quarter sectional view illustrating a modified
pin and box connection of the present invention having compression
rings positioned about and within the pin and box connection with
the compression rings having a greater spring back than the pin and
box;
[0025] FIG. 4 is a quarter sectional view of a two-step threaded
pin and box connection of the present invention employing high
spring back compression seal rings carried externally about the
engaged pin and box connection;
[0026] FIG. 5 is a quarter sectional view of a two-step threaded
pin and box connection of the present invention employing high
spring back compression rings carried externally of the box and
between the pin and box;
[0027] FIG. 5A is a partial, enlarged sectional view illustrating
details of a high spring back compression ring disposed between the
partially engaged pin and box of the connection of FIG. 5;
[0028] FIG. 5B is a view of the detail of FIG. 5A illustrating the
pin and box fully engaged;
[0029] FIG. 6 is a quarter sectional view of a modified form of a
connection of the present invention employing external and internal
high spring back compression rings in a single thread step
connection;
[0030] FIG. 7 is a quarter sectional view of a modified form of a
connector of the present invention illustrating a high spring back
compression ring disposed between axial shoulders in the pin and
box of the connector;
[0031] FIG. 8 is an enlarged detail view, in section, of a
shouldering area in a modified connector of the present invention
with a high spring back compression ring disposed between a pin and
box to form a crush seal following the radial expansion of the
connector;
[0032] FIG. 9 is an enlarged detail, in section, of a shouldering
area in a modified connector of the present invention with a high
spring back crush seal disposed in a shouldering area of the
connector to provide a crush seal following make up and radial
expansion of the connector;
[0033] FIG. 10 is an enlarged detail, in section, illustrating the
crush seal of FIG. 9 after the connector has been expanded;
[0034] FIG. 11 is an enlarged detail, in section, of a modified
high spring back crush seal of the connector of the present
invention positioned between a pin and box shoulder before radial
expansion of the connector;
[0035] FIG. 12 is an enlarged quarter sectional view of the crush
seal illustrated in FIG. 11;
[0036] FIG. 13 is an end view taken along line 13-13 of FIG. 12
illustrating one half of the crush seal of FIG. 11;
[0037] FIG. 14 is an enlarged detailed cross-sectional view of a
compression ring trapped by dovetail engagement in an annular
groove of an outer connection member of the present invention for
compressing the outer connection member radially inwardly after the
connector is expanded radially;
[0038] FIG. 14A is an embodiment similar to that of FIG. 14
illustrating a modified, multi part compression ring designed to
facilitate assembly of the ring into a receiving groove;
[0039] FIG. 15 is a detailed quarter sectional view of an engaged
pin and box of the present invention illustrating a compression
ring between two metal tubular sections to produce an axial sealing
force between the sections after the sections have been radially
extended;
[0040] FIG. 16 is a quarter sectional view of an expandable,
multi-part metal seal ring disposed between two tubular connectors
of the present invention before being radially expanded;
[0041] FIG. 16A is an enlarged detail of the seal ring of FIG. 16
before radial expansion of the connector;
[0042] FIG. 16B is an enlarged detail of the seal ring of FIG. 16
after radial expansion of the connector;
[0043] FIG. 17 is a quarter sectional view of two connectors of the
present invention with differing spring back characteristics and
having a non-interfering cylinder area that seals after radial
expansion of the connectors;
[0044] FIG. 18 is a quarter sectional view of a connector of the
present invention having an annular sleeve disposed between the pin
and box connection; and
[0045] FIGS. 18A-18F are alternative cross-sectional designs for an
annular sleeve that may be used in the manner illustrated in FIG.
18.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0046] Referring to FIG. 1, a connector of the present invention is
indicated generally at 10. The connector 10 is one of multiple
connectors used to form a string of casing S being run into a
wellbore W. The connector 10 is formed with a coupling 11 engaging
the ends or pins 12 and 13 of pipe bodies 14 and 15, respectively.
The pin 12 forms a pressure seal with the coupling 11 at the
annular sealing areas 16 and 17. The pin 13 forms a pressure seal
with the coupling 11 at the annular sealing areas 18 and 19.
[0047] The material or configuration of the coupling 11 is selected
to have a higher spring back than that of the material or
configuration of the pipe sections 14 and 15. A forging tool 20
passing through the center of the assembly of the pipes 14, 15 and
coupling 11 radially expands the components into the wall of the
wellbore W. The expansion exceeds the elastic limit of the
components which permanently increase the dimensions of a central
passage 21 extending axially through the pipes and coupling.
[0048] Once the forging tool 20 has expanded the connection 10 and
is removed from the central passage 21, the materials of the pipes
14 and 15 and the coupling 11 spring back slightly toward their
unexpanded positions. The material or configuration of the coupling
11 exhibits a greater tendency to return to its non-expanded
condition than do the materials or configurations of the pipes 14
and 15. The difference in the spring back of the materials produces
a compressive bearing pressure between the pipe pins 12 and 13 and
the coupling 11. The increased bearing pressure functions to
restore the initial pre-load and/or improve the residual mechanical
engagement and pressure seal between the pins and the coupling
following the radial expansion.
[0049] FIG. 2 illustrates a connector indicated generally at 24
having engagement with two pins 25 and 26 threadedly received
within a coupling 27 in a configuration similar to the single step
thread configuration schematically illustrated in FIG. 1. The
threads of the pins and coupling of FIG. 2 are a two-step design.
The pin 25 seals with the coupling 27 at annular sealing areas 28,
29 and 30. The pin 26 seals with the coupling 27 at annular sealing
areas 31, 32 and 33. The two-step threads 35 and 36 formed between
the pins and coupling 27 are illustrated as having a hook profile.
In a preferred form of the invention, pin ends 25a and 26a and the
central coupling area 27a have a reduced internal diameter as
compared with the internal diameter of the adjoining bodies of
pipes 25 and 26.
[0050] In one form of the invention, the coupling 27 may be
constructed of aluminum or an aluminum alloy. The material of the
pins 25 and 26 may be a common grade carbon steel. When the engaged
pins 25 and 26 and coupling 27 are expanded radially outwardly
beyond their elastic limits, the larger spring back characteristic
of the aluminum coupling imposes a residual radial sealing pressure
against the carbon steel pins at the seal areas 28, 29, 30, 31, 32
and 33. The decreased diameters at 25a, 26a and 27a impose greater
radial expansion of the overlaying connection, increasing the
resulting spring back effect and enhancing the seal and mechanical
engagement. The hook profile of the threads 35 and 36 assists in
maintaining connection between the engaged threads during and after
the expansion process.
[0051] FIG. 3 illustrates a substantially flush joint connection,
indicated generally at 39, employing circumferential compression
bands 42, 43 and 44 and a central compression seal 50 to increase
the sealing and mechanical engagement of the connection following
radial expansion of an engaged pin 40 and box 41. The
circumferential compression bands 42, 43 and 44 are positioned
externally of the connection 40 about critical annular seal areas
46, 47 and 48, respectively. An internal compression ring 50 is
carried in a groove 51 provided in the box 41. The groove 51 has
radial sidewalls 51a and 51b that axially restrict the compression
ring 50. The material of the pins 40 and 41 may be a carbon grade
steel and the material of the bands 42, 43, 44 and 50 may be
beryllium copper, titanium, aluminum, or other suitable material
having a greater spring back than carbon steel. The bands 42, 43,
44 and 50 may also be made of carbon steel that has been configured
or structured to produce a greater spring back than the pins 40 and
41.
[0052] Following radial expansion of the connection 39, the
compression bands 42, 43 and 44 spring back to a greater degree
than do the pin and box. The result is an increased bearing
pressure created at the respective underlying sealing areas 46, 47
and 48. Additionally, an increased bearing pressure is exerted
between the central compression ring 50 and the pin 40 as well as
the sides 51a and 51b of the groove 51, further enhancing the seal
and mechanical lock between the pin and box.
[0053] FIG. 4 is a quarter sectional view illustrating a two-step
threaded connector indicated generally at 60. The connector 60 is
formed by an engaged pin 61 and box 62. Annular compression seal
bands 65, 66 and 67 encircle critical sealing areas 69, 70 and 71
respectively, in the connector 60. The material or configuration of
the seal bands 65, 66 and 67 has a higher spring back than that of
the pin 61 and box 62 so that, following radial expansion, a
resultant compressive force is exerted in the critical sealing
areas 69, 70 and 71.
[0054] FIG. 5 illustrates a connector, indicated generally at 80,
employing annular compression bands 81, 82 and 83 encircling an
engaged pin 85 and box 86. A compression ring 88 is positioned in
the connection between the pin 85 and the box 86. The materials or
configuration of the compression bands 81, 82, 83 and ring 88 have
a greater spring back than that of the pin 85 or box 86. After
radial expansion, the greater spring back of the bands 81, 82 and
83 and the ring 88 increase the radial bearing pressure in the
engaged seal surfaces between the pin and box connection.
[0055] FIG. 5A illustrates details in the placement of the
compression ring 88 between the pin 85 and box of the connector 80.
The ring 88 is received within an annular recess 95 in a shoulder
92 of this box thread. A central shoulder 90 formed intermediate
the ends of the threaded pin area is adapted to engage the shoulder
92 formed intermediate the ends of the threaded box area to provide
a metal-to-metal engagement between the pin and box at their fully
made up position. The pin and box detail of FIG. 5A is illustrated
before full engagement of the two components.
[0056] FIG. 5B illustrates the connector 80 fully engaged, after
radial expansion, with the compression ring 86 confined within the
circumferential groove 95. The greater spring back of the
compression ring 88 relative to that of the box 86 and pin 85
causes it to exert a compressive force against the box material
underlying the groove 95 to produce an enhanced seal in the seal
area 88a between the pin and box.
[0057] In operation, with the material of the compression bands 81,
82, 83 and ring 88 having a higher spring back characteristic than
that of the pin 85 and box 86, radial expansion of the connection
80 produces a compressive force at each of the compression bands
and ring, enhancing the mechanical and sealing engagement between
the pin and box. Additionally, the greater spring back of the
internal compression ring 88 following the radial expansion
produces a compressive force between the pin and box at the seal
area 88a to further enhance the seal between the pin and box.
[0058] FIG. 6 illustrates a flush joint connector indicated
generally at 100 in which a box 101 is engaged with a pin 102.
Annular compression bands 103, 104, and 105 encircle the box 101 to
provide radial compression following expansion of the connector
100. An internal compression ring 109 is positioned between the tip
of the pin 102 and the box 101. A greater spring back
characteristic provided in the compression ring 109 relative to the
pin 102 increases the sealing pressure between the pin and box
following radial expansion of the connector.
[0059] FIG. 7 illustrates a connector indicated generally at 120
having a compression ring 121 positioned between shoulders in a pin
122 and box 123. The compression ring 121 is designed to spring
back more than the pin and box following radial expansion to
provide an increased axial force between the pin and box to enhance
the seals achieved at annular seal areas 124 and 125.
[0060] The pin and box of the connector 120 are initially engaged
with a snap fit. During initial assembly, the pin 122 is physically
forced axially into the box 123 causing the external tapered end
area of the pin in the seal area 124 to slide under the internal
tapered seal area of the box in the seal area 125. The seal ring
121 is preferably positioned on the pin 122 before the pin and box
are snapped together. If desired, the pin and box may be threaded
so that the axial closing of the pin and box during thread make up
effects the snap-together of the connection.
[0061] FIG. 8 illustrates a connection, indicated generally at 130,
between a box 131 and pin 132. An annular crush seal 133 is carried
in an annular groove 135 in the pin 132. At full engagement of the
pin and box, a pin shoulder 137 engages a box shoulder 138. During
radial expansion of the connector 130, the crush seal 133 is
extruded from the groove 135 into an annular space 139 between the
pin and box, as indicated by the dotted line configuration 133a.
The material of the crush seal 133 is selected to have a spring
back characteristic such that, following expansion, a resultant
compressive force is exerted by the material of the crush seal
against the surrounding components of the pin and box.
[0062] FIG. 9 illustrates a connector 140 having an annular crush
seal 141 positioned in an annular groove 142 of a shoulder 143
formed in the threaded area of a pin 144. The crush seal 141 has a
T-shaped cross-section. A shoulder 147 formed in the threaded area
of a box 148 is adapted to engage the crush seal 141 at the full
make up position of the pin and box, causing the material of the
crush seal to extrude into the shoulder area and adjoining seal
area between the pin and box as illustrated in FIG. 10. The
extrusion of the crush seal material 141 occurs during the final
make up of the pin and box. The material of the crush seal is
selected to have a greater spring back than that of the material of
the pin and box. Subsequently, when the connection is expanded
radially, the material of the crush seal produces an axially and
radially directed compressive force between the engaged pin and box
components to enhance the seal between the two components.
[0063] FIGS. 11, 12 and 13 illustrate a connector indicated
generally at 149 having a crush seal 150 disposed between a box 151
and a pin 152. The material of the crush seal 150 has a greater
spring back characteristic than that of the pin and box. The crush
seal 150 has a Z-shaped cross-section with components 150a and 150b
that fit between the seal areas of the mating connection segments.
The make up engagement of the shoulders between the box 151 and pin
152 extrudes the material of the crush seal 150 into the adjacent
shoulder and seal areas. Subsequent radial expansion of the
connector 149 produces an increased bearing pressure between the
crush seal material 150 and the confining materials of the pin and
box of the connection 149 to enhance the seal between the two
components.
[0064] FIG. 14 illustrates a section of a connector, indicated
generally at 160, in which a box connection 161 engages a pin
connection 162. A compression ring 165 with a trapezoidal
cross-section is illustrated trapped within an annular dovetail
groove 167 formed internally of the coupling 161. After the
connector 160 is radially expanded, the higher spring back
characteristic of the compression ring 165 acting through its
confinement within the dovetail box groove 167 draws the box 161
radially inwardly toward the pin 162 to increase the sealing
engagement between the two components.
[0065] FIG. 14A illustrates a composite compression ring formed of
three split-ring segments 165a, 165b and 165c. In assembling the
composite compression ring, the segments 165a and 165c are first
inserted into the groove 167 and the center component 165b is then
inserted to lock the composite compression ring into the groove.
The material or configuration, or both, of the split-ring segment
165b may be different from that of the split-ring end components
165a and 165c to increase the spring back axial forces exerted on
the end components after the radial expansion.
[0066] FIG. 15 illustrates a connector 170 in which a box
connection 172 engages a pin connection 173. At full engagement,
the section 172 and 173 meet along an annular, frustoconical
internal seal surface 175. A compression ring 177 is received
within an annular groove 178 in the pin 173 and a corresponding
annular groove 179 formed in the box 172. During assembly, the
compression ring 177 is positioned in either the pin groove 178 or
box groove 179. At complete make up, the two grooves 178 and 179
come together to completely enclose the compression ring as
illustrated in FIG. 15. After the connector 170 is radially
expanded, the higher spring back characteristic of the material of
the compression ring 177 increases the bearing pressure between the
engaged surfaces along the seal area 175 to enhance the seal
between the pin and box. The ring 177 also seals against the pin
and box to further enhance the seal between the components.
[0067] FIG. 16 illustrates a two-step thread connection, indicated
generally at 180, having an expandable metal seal ring 181 disposed
intermediate the threads formed in a box 183 and a pin 184 of the
connection. As best depicted in FIG. 16A, illustrating the
connector before radial expansion, the seal ring 181 is comprised
of two annular sections 181a and 181b that are respectively
received within an annular box groove 185 and an annular pin groove
187. Annular seal areas 188 and 189, illustrated in FIG. 16B, are
formed on either side of the metal seal ring 181. The dimensions
and configuration of the seal sections 181a and 181b cooperate with
the configuration and dimensions of the grooves 188 and 189 to
permit the box and pin to be threaded together and tightened into
the pre-expansion position illustrated in FIG. 16A.
[0068] The annular sections 181a and 181b are illustrated with
semi-oval cross-sections having flat bases positioned together to
form a composite oval configuration. The two-piece construction and
oval shape permit assembly of the pin and box to their full make up
position with the seal ring members being carried within the
respective grooves 185 and 187.
[0069] In the illustrated configuration of FIG. 16, the spring back
in the seal rings 181a and 181b after radial expansion of the
connector 180, as indicated in FIG. 16B, locks the pin and box
together and seals against the two components of the connector. The
result is an enhanced mechanical connection with improved sealing
characteristics.
[0070] FIG. 17 illustrates a modified form of a connection of the
present invention indicated generally at 190. The connector 190
includes a box 191 and pin connection 192. A post expansion seal
area, indicated generally at 193, is provided by selective
dimensioning of the components of the pin 191 and box 192 in the
areas indicated by the axial pin and box dimension "X," the
overlapping dimension "Y" between the pin and box in the
overlapping area along the dimension X, and the wall thickness "Z"
of the box 191. Appropriate sizing of the materials in the areas
defining the X, Y, Z dimensions produces a spring back in the pin
material that cooperates with the spring back of the box material
to increase the post expansion bearing pressure between the pin and
box in the overlapping area X. In the modification of FIG. 17, the
materials of the pin and box may be identical. The difference in
spring back is achieved by dimensioning the overlapping components
of the pin and box whereby the spring back value is a function of
material volume and configuration rather than the different
metallurgical characteristics of the materials of the pin and
box.
[0071] FIG. 18 of the drawings illustrates a modified form of the
connection of the present invention indicated generally at 200. A
metal sleeve seal element 205 is positioned in the two-step thread
spacing between an engaged box 206 and pin 207. The radially
internal and external surfaces of the element 205 are formed from
radially spaced, parallel frustoconical surfaces defining an
annular body with inside and outside diameters tapering along the
central axis of the seal. The diameters of the component 205
decrease in size in a direction from the base to the tip of the
pin. The axial length of the component 205 is selected to be
sufficiently large to accommodate axial changes in physical
dimension of the component occurring during radial expansion of the
connection and the spring back following passage of the expansion
tool.
[0072] Annular voids 208a, 208b and 209a, 209b are provided in the
overlapping seal areas formed between the box 206 and pin 207 on
either side of internal shoulders formed in the pin and box
threaded areas. The voids 208a, 208b, and 209a, 209b receive
material extruded during the radial expansion of the pin, box and
annular seal 205. Following the radial expansion, material extruded
into the voids is allowed to partially return to the source
component to fill any spring back induced spacing between the pin
and box following the radial expansion.
[0073] In a preferred form of the connection 200, the internal
surface of the pin 207 is equipped with an internal diameter
protrusion 210 in the area underlying the seal component 205. The
protrusion 210 produces additional radial displacement during the
expansion of the connection to enhance or increase surface contact
with the component 205 in the expanded state of the connection.
[0074] In use, the long, thin, tapered metal sleeve 205 is
positioned over the pin 207 before the pin is inserted into the box
206. The dimensions of the surfaces contacting the seal component
205 are preferably selected such that, at the full make up position
of the pin and box, the component 205 is compressed radially
sufficiently to form a pressure seal with the pin and box
components of the connection. During this initial make up, the seal
205 is preferably compressed radially sufficiently to create a
pressure seal that seals pressure from either the external or
internal directions.
[0075] The extended axial length of the metal seal 205 minimized
the adverse effects of axial deformation occurring during the
radial extension of the connector. In many applications to
connections of typical casing sizes, the axial length of the sleeve
205 may be as much as one inch or more. The axially tapering shape
of the seal 205 causes the plastic deformation resulting from the
radial expansion to increase the seal effectiveness between the
engaged pin and box due to the differential spring back occurring
between the larger and smaller ends of the seal element 205.
[0076] The seal element 205 is preferably constructed from a metal
with an elastic modulus that is substantially lower than that of
carbon steel, such as titanium or copper-beryllium. The preferred
form of the seal element 205 is as illustrated in FIG. 18 with
smooth internal and external circumferential surfaces engaging the
underlying pin and surrounding box.
[0077] FIG. 18A illustrates a modified cross-section design 205a
for the seal 205 having substantially similar end diameters and an
arcing section increasing in diameter toward the center of the seal
between the two ends.
[0078] FIG. 18B illustrates a modified cross-section design 205b
for the seal 205 having a lens-shaped configuration.
[0079] FIG. 18C illustrates a modified cross-section design 205c
for the seal 205 having an elongate, oval cross-section.
[0080] FIG. 18D illustrates a modified cross-section design 205d
for the seal 205 having a smooth external circumferential surface
and an internal surface provided with semicircular annular
grooves.
[0081] FIG. 18E illustrates a modified cross-section design 205e
for the seal 205 in which both the internal and external
circumferential surface of the seal are provided with annular, flat
bottom grooves.
[0082] FIG. 18F illustrates a modified cross-section design 205f
for the seal 205 in which curved annular grooves are provided on
the internal and external circumferential surfaces of the seal with
the grooves of the internal and external surfaces being offset
axially relative to each other.
[0083] It may be appreciated that while metals have been described
as the materials of choice for producing enhanced mechanical and
sealing engagement between plastically deformed connected
components, other materials may also be employed to attain the
desired result. Thus, certain plastics as well as other materials
may be used alone or in combination with metals or other plastics
or other synthetic materials to produce a connector of the present
invention. A primary requirement of the invention is that the
component with a material or design exhibiting a greater spring
back characteristic be position relative to a component with a
material or design exhibiting a lesser spring back characteristic
so that a resultant compressive force exists between the two
components following their plastic deformation. It will also be
appreciated that while most of the embodiments described herein
have positioned the components with the greater spring back
characteristic internally of those with a lesser spring back
characteristic, the components may be arranged such that mechanical
engagement between the two different material produces the desired
compressive force without placing the larger spring back component
internally of the smaller spring back component.
[0084] It will be understood that various modifications can be made
in the design, construction and operation of the present inventions
without departing from the spirit or scope of such inventions.
Thus, while the principal preferred construction and mode of
operation of the inventions have been explained in what is now
considered to represent their best embodiments, which have been
illustrated and described herein, it will be understood that within
the scope of the appended claims, the inventions may be practiced
otherwise than as specifically illustrated and described.
* * * * *