Note: Descriptions are shown in the official language in which they were submitted.
CA 02558701 2000-09-06
DESCRIPTION
METHOD AND APPARATUS FOR HANGING TUBULARS IN WELLS
BACKGROUND OF THE INVENTION
The field of the present invention is well drilling and completion systems.
Well drilling and completion equipment includes tubulars which are variously
characterized as casing, tubing and liner. For universal application, they are
cylindrical in
to shape and of a length in compliance with the American Petroleum Institute
Standard SC.
The term "casing" is typically applied to tubulars which are larger in
diameter and used to
support the earth's encroachment when drilling a bore hole for a well. Often
casing is
cemented to the bore hole to define a sound structural member and to prevent
migration of
unwanted gases, water or other fluids outwardly of the casing. Casing is
typically
i5 assembled from 40 foot long tubulars with threaded couplings. Wells can
extend for
several miles into the earth. As the well increases in depth, the hydraulic
pressures to
which the casing is subjected to increase. Decreases in casing diameter with
increasing
depth is common, often to avoid experiencing excessive force from such high
pressures.
Such decreases typically occur in step function as smaller casing is employed.
20 "Liner" is typically made up of tubulars in an area of well production.
Liner can
have portions with slots prefabricated through the wall, end closure elements
and the like.
Liner is typically smaller in diameter than casing and is typically placed in
wells after
casing to extend from casing into production zones.
Other tubing may be employed within casing to bring production to the surface
2s and for other communication within wells. This too is placed in wells after
casing and has
a reduced diameter.
To insure the flow of fluids with or without entrained solids are
appropriately
directed within wells, packers or annular seals are frequently employed to
span gaps at
radial steps in tubular construction within wells. Packers are also employed
to insure the
3 o blockage of pressure from unwanted areas.
Additionally, structural support from above frequently is needed for such
placements. The compression of tubular strings through placement on the bottom
is often
considered to be detrimental to the pressure integrity of the structure.
Consequently,
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suspending liner or casing in tension is preferred. Hangers typically are used
which
employ wedges or other structural devices to grip the inner tubular.
Combinations of
packers and hangers are also used.
Accordingly, it is an object of the present invention to provide hanging
methods for wells and apparatus associated therewith.
SUMMARY OF THE INVENTION
The present invention is directed to methods for hanging tubulars in wells
including the expansion of the inner tubular beyond its elastic limit
outwardly against
an outer tubular with the outer tubular experiencing sufficient deformation to
place
the final assembly in a tight relationship. Tubular hanging is accomplished.
Sealing
may also be achieved. Apparatus to these ends is separately contemplated.
In a first separate aspect of the present invention, a method for hanging an
inner tubular and an outer tubular includes an overlapping of the tubulars.
The firmer
tubular is expanded partially or fully circumferentially past the yield point
and the
outer tubular is expanded partially or fully circumferentially by the inner
tubular, the
expansion being sufficient that elastic recovery for the inner tubular is less
than elastic
recovery for the outer tubular. A structural hanging of the inner tubular on
the outer
tubular is thus accomplished. Depending on the materials employed, a sealing
may
also be accomplished at the same time. Additional ductile sealing material may
be
employed as well. The foregoing can be accomplished without expanding the
outer
tubular beyond the yield point when that is preferred.
In a second separate aspect of the present invention, a method for hanging a
first tubular and a second tubular includes an overlapping of the tubulars
with a spacer
therebetween which is substantially incompressible in the radial direction.
The inner
tubular is expanded partially or fully circumferentially past the yield point
and the
outer tubular is expanded partially or fully circumferentially by the spacer.
A
structural hanging of the inner tubular on the outer tubular is thus
accomplished.
Depending on the materials employed, a sealing may also be accomplished at the
same time. The spacer may have seals and structure allowing for its easy
partial or
full expansion circumferentially through portions thereof. Additional ductile
sealing
material may be employed as well.
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In a third separate aspect of the present invention, the prior aspects are
contemplated to be specifically employed for hanging cylindrical liners within
cylindrical casings.
In a fourth separate aspect of the present invention, laterally hanging a
tubular
is accomplished through drilling diagonally through the wall of a casing,
placing a
tubular through that wall and expanding the tubular past the yield point and
the casing
by the tubular. The tubular extending into the casing may then be drilled out.
In this
way, access to the main bore as well as to the lateral bore or bores remains.
In a fifth separate aspect of the present invention, a spacer contemplated for
I 0 use between tubulars of different diameters is contemplated. A tubular
body includes
inner and outer circumferential channels with ductile seals arranged therein.
Longitudinal slits through the wall of the tubular body facilitate expansion
of the
spacer. The slits are staggered and do not extend to the circumferential
channels.
In a sixth separate aspect of the present invention, a tubular expander
includes
a hydraulic ram with a shoulder and a draw bar extending through the shoulder.
A
collet is associated with the draw bar and cooperates with the draw bar
through
beveled surfaces to effect a selected expanded state. An annular piston may be
employed to move the collet on the draw bar to control collet expansion. The
shoulder on the hydraulic ram may also be extended to receive at least a
portion of the
collet such that the maximum diameter of the collet may be drawn substantially
fully
through the end of the tubular.
In a seventh separate aspect of the present invention, the tubular expander of
the prior aspect is contemplated to be associated with a tubular with the
collet
expanded to firmly engage the tubular.
In an eighth separate aspect of the present invention, combinations of the
foregoing aspects are contemplated.
In a ninth aspect of the present invention there is provided a tubular
expander
comprising:
a hydraulic ram including a cylinder with a shoulder at one end and a draw bar
extending through the shoulder, the draw bar having a beveled outer surface
portion
and an outer shoulder; and
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3a
a collet about the draw bar including a ring and segments cantilevered from
the ring along the draw bar toward the hydraulic ram, the segments each having
a
beveled inner surface portion slidably mating with the beveled outer surface
portion to
radially expand the collet with axial movement of the collet relative to the
draw bar
toward the cylinder and an inner shoulder facing the outer shoulder of the
draw bar to
limit movement of the collet relative to the draw bar, the shoulder of the
cylinder
extending beyond the cylinder to receive at least a portion of the collet
therein.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a partial cross-sectional view of a tubular within a casing with a
tubular expander.
Figure 2 is a partial cross-sectional view of a tubular within a casing
expanded
into hanging relationship therewith.
Figure 3 is a cross-sectional detail view of the wall of Figure 2 with an
added
seal layer.
Figure 4 is a spacer shown in partial cross section.
Figure 5 is a tubular expander.
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Figure SA and SB show the tubular expander illustrated in partial cross
section.
Figures 6A-6H are a sequential schematic series of cross sections of a multi-
lateral tubular placement.
s DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning in detail to the drawings, Figure 1 illustrates a tubular, shown to be
a
casing 10 in this embodiment, understood to be positioned within a well bore
(not shown).
The lower end 12 of the casing 10 does not extend to the bottom of the well
bore. An
assembly for hanging a second tubular, shown to be a liner 14 in this
embodiment, within
to the casing 10 is positioned with the liner 14 in an overlapping
relationship with the casing
10. This second tubular may be casing, liner or other tubing with a smaller
diameter than
the first tubular with which it is positioned. The liner 14 extends further
into the well an
indeterminate distance. The casing 10 as well as the liner 14 may be drawn
from well
drilling stock which are conventional standard tubulars.
is A spacer 16 may be located between the liner 14 and the casing 10. When a
spacer 16 is used, it preferably extends to surround the area of the liner 14
which is
overlapping with the casing 10 and which is to be expanded outwardly against
the casing
10. A wide variety of spacers 16 may be employed. Separate spaced collars, a
wrapping
of substantially incompressible filler material and the like are contemplated.
One such
2 o spacer 16 is best illustrated in Figure 4.
The spacer includes a tubular body 18 with outer channels 20 near either end.
Inner channels 22 are also near either end. Both channels 20 and 22 receive
conventional
sealing material 24 which is packed to extend in the uncompressed state
outwardly from
the channels 20 and 22.
2 s The material of the tubular body 18 is to be substantially incompressible
in the
radial direction. In this regard, the material is preferably similar to that
of the casing 10
and the liner 14. As the liner 14 eXpands, the spacer 16 is anticipated to
transfer certain of
the load outwardly into the casing 10. The substantially incompressible nature
is that
which is sufficient to accomplish an appropriate force transfer.
3o The tubular body 18 further has slits 26. These slits are longitudinally
staggered
such that angularly adjacent such slits 26 are displaced longitudinally as can
be seen in
Figure 4. The slits preferably do not extend longitudinally along great
distances. C-
shaped slits 26 are contemplated as specifically illustrated. The slits 26 act
to create an
CA 02558701 2000-09-06
expandable metal structure which resists partial or full circumferential
expansion
substantially less than the tubular liner 14. Even so, radial
incompressibility is not
significantly compromised.
The slits 26 do not extend fully to the ends of the tubular body 18 or even so
far
as the channels 20 and 22. In this wav. an annular closed collar is defined at
each end.
Each collar will require additional force for expansion. The ductile sealing
material 24
will easily expand partially or fully circumfercntially within the channels 20
and 22.
A ductile sealing material which may be a polymeric substance or a ductile
metal
filler material may overlay the liner or the pacer 16 when one is employed.
One such
io ductile sealing layer 28 is illustrated in the detail of Figure 3. A
similar sealing layer (not
shown) may also or alternatively be employed where appropriate between the
liner 14 and
the spacer 16.
A tubular expander is illustrated for cooperation with the liner 14. This
tubular
expander, generally designated 30, is shoNm in detail in Figures SA and SB and
is shown
is in position before expansion in Figure 1.
The tubular expander 30 includes a hydraulic ram 32 which includes a cylinder
34 having ram annular pistons 36 and 37. A draw bar 38 is positioned inwardly
of the
cylinder 34. The draw bar 38 has a central bore 40 which may be closed at the
distal end
thereof by a cap 42 or other means such as additional equipment further down
hole. The
2o draw bar 38 includes shoulders 44 and 46 which, with the bar itself, the
cylinder 34 and
the ram annular pistons 36 and 37 define ram expansion spaces 48 and 50,
respectively.
Lip seals or O-rings are appropriately positioned to ensure sealing of the ram
expansion
spaces 48 and 50. The shoulder 46 is shown to be a separate element rather
than integral
as is shoulder 44. This is appropriate for ease of assembly. Further,
additional shoulders
2s 46 may be associated with additional ram annular pistons 36 and 37 where
more force is
necessary. Passages 52 are shown to extend from the central bore 40 to the ram
expansion
spaces 48 and 50 for the delivery of high pressure fluid. Relief passages 53
avoid pressure
buildup behind the piston 37 as the hydraulic ram 32 moves through its stroke.
Depending upon the pressure which may be necessary for expanding a tubular,
3 o not only may force advantage be achieved through the multiplication of ram
annular
pistons 36 but a hydraulic intensifier may be employed above the tubular
expander 30.
The principles of hydraulic intensifiers are well known as requiring a small
input piston
capable of traveling through a relatively large distance and driving a larger
output piston
CA 02558701 2000-09-06
capable of traveling through a much shorter distance and exerting a far higher
force. The
hydraulic force generated by the larger piston would then be input into the
central bore 40
for distribution through the passages 52 into the ram expansion spaces 48 and
S0.
The draw bar 38 extends from the cylinder 34 and receives a collet, generally
s designated 54. The collet 54 includes a ring 56 at its lower end formed in
two potions for
ease of manufacture. Segments 58 extend from the ring 56 about the draw bar 38
and
toward the hydraulic ram 32. These segments 58 are cantilevered from the ring
56 such
that they may be forced to expand outwardly from a retracted force neutral
position. Slots
60 define the segments 58 and are shown to include a jog at the thickest
portion of the
to collet 54 so as to provide continuous expansion force about the entire
collet.
The draw bar 38 includes a beveled outer surface portion 62 and an outer
shoulder 64 which extend fully about the draw bar 38. Each segment 58
similarly includes
a beveled inner surface portion 66 with an inner shoulder 68 facing the outer
shoulder 64
on the draw bar 38. As can be seen from Figures SA and SB, as the collet 54
moves
i5 downwardly relative to the draw bar 38, the beveled outer surface portion
62 and the
beveled inner surface portion 66 act together to expand the segments 58
outwardly in a
radial direction. The outer shoulder 64 and the inner shoulder 68 cooperate to
limit the
relative travel between the collet 54 and drawbar 38 so as to limit the
expansion of the
collet.
2o To effect the foregoing relative longitudinal displacement of the collet 54
on the
draw bar 38, an annular piston 70 associated with the ring 56 of the collet 54
cooperates
with the draw bar 38 to define an expansion space 72. A further passage 74
extends from
the central bore 40 to the expansion space 72. Seals about the expansion space
72 inhibit
leakage. Thus, the pressure commencing to draw the hydraulic ram 32 upwardly
also
2s drives the collet 54 downwardly to expand the segments 58.
A retaining ring 76 located at the distal end of the segments 58 is affixed to
the
draw bar 38. This ring 76 includes a frst cavity 78 to retain the ends of the
segments 58
when in the contracted state as illustrated in Figures SA and SB and a second
cavity 80 to
retain the ends of the segments 58 when in the expanded state.
3o Referring back to the cylinder 34 of the hydraulic ram 32, a shoulder 82 is
located
at the lower end of the cylinder 34 and displaced therefrom. The draw bar 38
extends
through this shoulder 82. The extension of the shoulder 82 is of sufficient
length and inner
diameter such that it can receive the upper end of the collet 54 and the
retainer ring 76.
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The extension of the shoulder 82 is to the maximum diameter of the collet 54
when in the
expanded state. Extraction of the tubular expander assembly once drawn through
the full
stroke is thereby accomplished without further tubular expansion of the liner
14.
In operation, a smaller diameter tubular, such as the liner 14, selected to be
placed
within a larger diameter tubular, such as the casing 10, already in position
within a well.
A spacer 16 may first be positioned about the liner 14 adjacent one end,
particularly if the
necessary expansion of the liner 14 would otherwise be excessive. The spacer
or spacer
elements are selected to extend substantially the length of the portion of the
Liner I4 to be
expanded. Ductile sealing material may be added about the liner. Where a
spacer is
io present, such ductile sealing material may be either inwardly of the spacer
16 or outwardly
of the spacer 16 or both.
Once the tubular has been prepared, a tubular expander is placed therein. A
tubular expander is selected with the appropriate piston stroke to expand a
preselected
length of the liner 14. The draw bar 38 is extended such that the widest area
of the toilet
i5 54 is in location to expand the desired portion of the liner 14. With a
spacer involved, the
collet is arranged just longitudinally outwardly of the spacer 16. With the
appropriate
length selected, the shoulder 82 on the hydraulic ram 32 abuts against the
near end of the
liner 14. Some pressure may be supplied to the central bore 40 so as to set
the collet 54
within the liner 14 with enough force so that the entire liner assembly can be
supported by
2o the collet 54 as the assembly is lowered into the well.
Once in position with the liner 14 overlapping the casing 10 at least to the
extent
of the spacer 16, high pressure fluid is directed down the drill pipe to the
central bore 40 of
the draw bar 38. This pressure acts to drive the collet 54 on the draw bar 38
to the fully
expanded position. The pressure also acts to draw the expanded collet 54
upwardly
z s through the liner 14 toward the shoulder 82 of the hydraulic ram 32.
The inner diameter of the casing 10 and the outer diameter of the liner 14 are
selected along with the appropriate thickness of the spacer 16, if used, such
that operation
of the collet 54 being drawn through the portion of the liner 14 will expand
the liner which
in turn expands the spacer 16. The expansion of the liner 14 is beyond the
yield point of
3o the material. In this way the gap necessary for placement, either between
the liner 14 and
the casing 10 or the spacer 16 and the casing 10, is permanently closed. The
yield point of
any material is determined by convention, typically at .2% offset yield.
Because of the
necessary gap, significant plastic strain beyond the yield point is
anticipated.
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Either the liner 14 itself or the spacer 16 extends outwardly to expand the
casing
10. The assembly is preferably but not necessarily selected such that the
expansion of the
casing 10 remains within the elastic limit of the material. The elastic
expansion of the
casing 10 is such that, with the tubular expander withdrawn, the casing 10 is
able to
rebound enough to remain tight against the liner 14 or the spacer 16 and in
turn the liner
14. Further, it is commonly understood that the materials of oil field
tubulars are able to
be stretched in the yield range to as much as about 10% to 20% or more without
experiencing a significant decrease in strength. Competing effects of work
hardening and
reduction in cross-section accompanying the inelastic strain results. With
continued
to expansion, the reduction in cross section becomes the dominant factor and
strength
decreases. The strength of concern. is typically the longitudinal tensile
strength of the
tubular.
When expanded, the inner tubular expands more than the outer tubular per unit
of
circumference. Likewise, when recovering after the load is removed, the inner
tubular will
m . shrink less than the outer tubular to achieve the same ratio of recovery.
Consequently, the
outer tubular will remain in some tension and the inner tubular will remain in
some
compression if the two are expanded with the inner tubular expanding in excess
of the
yield point enough so that the inner tubular cannot recover to a position
where tension is
removed from the outer tubular. In other words, the outer tubular may remain
within the
2 o elastic limit but is preferably expanded enough so that its recovery when
unloaded by the
tubular expander is at least as great as the recovery of the inner tubular. A
minimum
expansion of both tubulars is preferred to achieve this result. Expansion to
the point that a
tubular begins to lose strength is avoided except in unusual applications.
Once the collet 54 has been drawn as far as possible through the shoulder 82
by
2s the draw bar 38, it is substantially free from the now expanded liner
portion 14. With this
accomplished, the drill string with the collet 54 attached can be withdrawn
from the well.
If other elements are located below the collet 54 on the drill string, they
may be employed
for gravel packing, cementing and the like.
Turning to the method of laterally hanging a tubular as sequentially
illustrated in
ao Figures 6A-6H, a first trip down the well with the liner in place includes
a whipstock 84 of
conventional design in association with a drill in liner 86 typically
employing a mud motor
and geosteering. In Figure 6A, the whipstock is being placed. In Figure 6B the
whipstock
84 is now set and disengaged from the drill in liner 86. In Figure 6C, the
drill in liner is
CA 02558701 2000-09-06
shown cutting a window or hole through the casing. The drilling continues
until the drill
in liner 86 has almost completely passed through the window in the casing. A
tubular
expander was included as part of the drill in liner assembly. Once the drill
in liner 86 has
been placed, the colIet is opened and drawn through the liner 86 across the
window in the
s casing. The liner 86 expands and becomes fixed within the window of the
casing. The
attachments are then withdrawn, leaving the drill in liner 86 in place.
In Figure 6F, a drill is shown being positioned down the well on a second trip
to
take out the stub of the drill in liner 86 which extends into the interior of
the casing. The
whipstock is then attached and withdrawn leaving a completed lateral bore and
a
io completed main bore with full bore access. The lateral liner is
mechanically connected
and provides a~ high pressure seal.
Accordingly, improved methods and apparatus are disclosed for the hanging of
tubulars within a well. While embodiments and applications of this invention
have been
shown and described, it would be apparent to those skilled in the art that
many more
~s modifications are possible without departing from the inventive concepts
herein. The
invention, therefore is not to be restricted except in the spirit of the
appended claims.
