Note: Descriptions are shown in the official language in which they were submitted.
CA 02491963 2007-04-26
1
LINING BORE HOLES BY USING TUBING EXPANSION
FIELD OF THE INVENTION
This invention relates to an ex-pansioxi method, and in
particular to a method of expanding tubing downhole.
BACKGROUND OF THE INVENTION
The oil and gas exploration and production industry is
making increasing use of expandable tubing in a wide
variety of applications, including use as caaing and liner,
in straddles, and as a support for expandable sand screens_
Initially, ex-pandable tubing was proposed for use primarily
in combination with traditional fixed diameter casing and
liner. However, more recently, various proposals have been
put forward to utilise expandable tubing to create wells of
substantially constant diameter ("monobore" wells), where
all or at least a significant proportion of the well is
lined with expanded tubing.
various forms of expansion tools have been utilised to
expand tubing downhole, including ex-patision cones and
mandrels which are pushed or pulled through tubing by
mechanical or hydraulic forces. Rotary expansion tools
have also been used, and these typically feature rollers.
which are urged outwardly, or which def ine a fixed
diameter, for rolling contact with the tubing to be
CA 02491963 2005-01-11
2
expanded; the tool is rotated aiZd advanced through the
tubing.
It is among the objeCtives of embodiments of the
present invention to provide sectioiis of bore lined with
expanded bore-lining tubing of a variety of diameters.
SUMMARY OF THE INVENTION
According to the present invention there is provided
a method of expanding tubing downhole, the method
comprising the steps of:
providing tubing of a first diameter;
running the tubing into a bore;
expanding a first section of the tubing to a second
diameter; and
expanding a second section of the tubing to a third
diameter.
The entire length of the tubing may be expanded, or a
portion of the tubing may remain unexpanded, at said first
diameter.
This aspect of the invention permits provision of
expanded downhole tubing hatiring sections of different
diameters, to suit the individual requirements of
respective sections of the bore. For example, a section of
bore may have been underreamed, and it may be desired to
line the bore with tubing which, when expanded, will define
2S a larger diameter bore within the underreamed section and
CA 02491963 2005-01-11
3
a smaller diameter bore beyond the ends of the reamed
section. In other applications, it may be convenient to
have a section of lined bore defining a larger diameter to
provide an annulus around, or otherwise accommodate, a
relatively large diameter device or tool, such as a
downhole pump. Thus it may then not be necessary to drill
an extended section of bore of a large diameter where only
a short section.of a larger diameter is required and may be
achieved by selective underreaming, provided of course that
the large=diameter tool or device may be run in through the
smaller di,ameter bore section. In another application, it
may be desired to expand a first section of tubing to a
larger second diameter and into sealing contact with the
surrounding bore wall, while it is desired to expand a
second section,of the tubing to a smaller third diameter to
provide an annulus between the expanded tubing and the bore
wall to accommodate a cement seal. The expansion of the
first section in this method would preferably involve use
of a compliant expander, that is-an expander that has the
ability to expand tubing to a non-uniform or.non-circular
form, and thus accommodate, for example, variations in the
bore wall diameter.
The first and second expansion steps may take place
simultaneously, and this may be achieved bv providing first
and second expansion tools on a common support, and
operating the expansion tools simultaneously on different
CA 02491963 2005-01-11
4
sections of the tubing. In this situation, the expansion
tools may take any appropriate form, including fixed
diameter expansion cones. Of course, if an expansion cone
is required to pass through a tubing section of smaller
diameter than the expansion cone without expanding the
section, the cone must be retractable or otherwise
configurable to assume a smaller diameter, as described for
example in applicant's US Patent No 6,012,523, the
disclosure of which is incorporated herein by reference.
In other embodiments, the second expaiision step may
follow the first expansion step. In this situation, a
common expansion tool may be utilised, such as a rolling
expansion tool provided with radially extendable expanding
members which may assume two or more diameters, the rolling
members being arranged in a first configuration for the
first expansion step and a second configuration for the
second expansion step. Alternatively, different expansion
tools may be utilised for the first and second expansion
steps and may be mounted on different support members.
Where the third diameter is larger than the second
diameter, the second section of tubing may be expanded to
the second diameter before being expanded to the third
diametex. -
The tubing may be formed of a single tubing length, or
may be formed of a plurality of tubing lengths which are
joined end-to-end. The configuration of the tubing may be
CA 02491963 2005-01-11
substantially constant, for example the tubing may consist
solely of solid walled tubing, or the configuration of the
tubing may varv along its length, for example including
solid walled sect:ions, slotted or otherwise perforated wall
5 sections, and sections formed of expandable sand screen.
Where the tubing comprises a plurality of tubing
lengths, these may be run into the bore and expanded
separately. In one embodiment, the ends of adjacent tubing
lengths may overlap. A first tubing length may be run into
the bore and expanded to said second diameter, or indeed
may already be of said second diameter. A second tubing
length may then be run into the bore, beyond the first
tubing length, but with the upper end of the second tubing
overlapping the lower end of the first tubing_ The upper
end of the second tubing then be expanded to said third
diameter, preferably such that the overlappirig ends of the
tubing are in sealing contact. The remainder of the second
tubing may then be expanded to said second diameter. This
process may be repeated for subsequent tubing lengths, to
create a lined bore of substantially constant diameter,
corresponding to the second diameter, but having relatively
short sections of tubing where the diameter corresponds to
said lesser third diameter. Typically, the difference
between the second and third diameters will correspond to
15 the wall thickness of the tubing and thus will be small,
relative to the bore diarneter. Nevertheless, the resulting
CA 02491963 2005-01-11
6
profiles may be useful for locating tools and devices in
the bore. The upper ends of the tubing sections mav be
chamfered or otherwise profiled, to provide a smooth
transition between the different diameter sections, or may
provide a ledge or otherwise abrupt transition, to assist
in locating tools or devices in the bores.
In other embodiments, the upper end of the second
tubing may be expanded to a smaller diameter, such that the
overlapping ends of the tubing are spaced apart or
otherwise define a fluid passage therebetween, to
facilitate flow of fluid between the overlapping ends.
This may be useful in cementing operations, where fluid is
displaced from the annulus between the second tubing and
the surrounding bore wall.
The invention also relates to bores lined in this
manner.
In other aspects of the invention, tubing of a first
.diameter may be expanded, intermediate its ends, to a
larger second diameter. That is, the tubing is expanded to
crear,e a"bulge" in the tubing.
In one embodiment, the end portions of the tubing may
form connections which are not extended, while the
intermediaLe section, which may be sandscreen or the like,
is expanded into contact with the surrounding bore wall.
In other aspects of the invention the tubi,ng may
initially feature sections of different diameters.
CA 02491963 2007-04-26
7
The invention also relates to apparatus for
implementing the method, and to a bore lined in accordance
with the method.
In another aspect, the invention provides a method of
lining a drilled bore, the method comprising the steps:
(a) running a first tubing length of a first diameter
into the bore;
(b) running a second tubing length into the bore and
through the first tubing length after the first tubing
length is in the bore, such that the second tubing length
overlaps with a lower end of the first tubing length;
(c) expanding at least a first portion of the second
tubing length where the tubing lengths overlap, to a second
diameter smaller than the first diameter; and
(d) expanding at least a second portion of a remainder of
the second tubing length to a third diameter larger than
the second diameter, wherein the second portion is longer
than the first portion and extends beyond the first tubing
length.
In another aspect, the invention provides a method of
lining a drilled bore, the method comprising the steps: -
(a) running a first tubing length of a first diameter
into the bore;
(b) expanding said first tubing length to a larger second
diameter;
(c) running a second tubing length into the bore after
step (a), such that an upper end of the second tubing
length overlaps with a lower end of the first tubing
length;
(d) expanding the upper end of the second tubing length
to a third diameter larger than said first diameter but
smaller than said second diameter; and
CA 02491963 2007-04-26
7a
(e) further expanding a majority of the second tubing
length to said second diameter.
In another aspect, the invention provides a method of
lining a drilled bore, the method comprising the steps:
(a) running a first tubing length into the bore, wherein
the first tubing length defines a first diameter;
(b) running a second tubing length into the bore after
step (a), such that an upper end of the second tubing
length overlaps with a lower end of the first tubing
length;
(c) expanding the upper end of the second tubing length
to a third diameter larger than the first diameter but
smaller than a second diameter;
(d) further expanding a majority of the second tubing
length to the second diameter; and
(e) expanding at least a portion of the first tubing
length to the second diameter larger than the first
diameter.
In another aspect, the invention provides a method of
lining a drilled bore, the method comprising:
running a first tubing of a first diameter into the bore;
thereafter, running a second tubing into the bore and
through the first tubing, such that the second tubing
overlaps with a lower end of the first tubing;
expanding at least a first portion of the second tubing
where the first and second tubing overlap, to a second
diameter, wherein expanding the first portion places the
second tubing in contact with the first tubing; and
expanding at least a second portion of the second tubing
adjacent the first portion to a third diameter larger than
the second diameter, wherein the second portion is longer
than the first portion and extends beyond the first tubing.
CA 02491963 2007-04-26
7b
BRIEF DESCRIPTION OF THE DRAWINGS
These and other aspects of the present invention will
now be described, by way of example, with reference to the
accompanying drawings; in which:
Figures 1 and 2 illustrate steps in a tubing expansion
operation in accordance with a preferred embodiment of the
present invention;
Figure 3 illustrates expanded tubing following the
expansion operation of Figures 1 and 2;
Figure 4 is a schematic illustration of a step in the
creation of a lined bore in accordance with a further
embodiment of the invention; and
Figure 5 is schematic illustration of a section of a
lined bore made in accordance with said further embodiment
of the invention_
DETAILED DESCRIPTION OF THE DRAWINGS
Figures 1, 2 and 3 of the drawings illustrates a part
of a drilled bore 10, of diameter Dl, which has been drilled
to access a subsurface hydrocarbon-bearing earth formation
12. Where the bore 10 intersects the formation 12, the
bore has been underreamed to a larger diar.teter DZ. A length
CA 02491963 2005-01-11
8
of expandable tubing 14, of initial or first diameter d,
has been run into the bore 10. As will be described, a
first section of the tubing 14a is expanded to a second
diameter dlwithin the section of the bore with a diameter
of D1, and a second section of the tubing 14b is expanded to
a third diameter d2 within the section of the bore with a
diameter of D2, as illustrated in Figure 3.
In the illustrated embodiment, the expansion is
achieved using a rotary expansion tool 20 which is run into
the bore with the tubing 14, and is mounted on the lower
end of a drill pipe string 22. of course in other
embodiments other forms of expansion tool may be utilised,
including expansion cones or mandrels. Also, fluid
pressure may be utilised to at least -assist in the
expansion operation. The tool 20 comprises a hollow body
24 defining at least one and preferably three
circumferentially spaced apertures 26 which each
accommodate a respective piston 28 (only two shown), each
piston providing mounting for a roller 30. The tool body
24 is in fluid communication with the hollow string 22,
such that hydraulic pressure rnay be applied to the tool
body interior and thus urge the pistons 28 radially
outwardly and bring the rollers 30 into contact with the
tubing 14, as will be described below. The leading end of
the body 24 provides mounting for further rollers 32 which
may be radially rnovable or fixed in a conical
CA 02491963 2005-01-11
9
configuratiot7, the maximum diameter described by the
rollers 32 being sirnilar to the diameter described by the
retracted or unextended rollers 30.
To expand the first section of tubing 14a, as
illustrated in Figure 1, the tool 20 is rotated in the
tubing and advanced axially through the tubing 14. The
rotating rollers 32 subject the tubing wall to local
compressive yield, leading to a decrease in wall thickness
and corresponding increase in tubing diameter. The rollers
32 are configured such that the tubing tends to expand to
the diameter dl.
Once the first tubing section 14a has been expanded,
pressurised fluid is supplied from surface to the expansion
tool 20, which pressure urges the pistons 28 and the
rollers 30 radially outwards as illustrated in Figure 2.
By rotating and advancing the now energised tool 20; the
tubing 14 is first expanded to the diameter dl by the action
of the fixed diameter rollers 32 and then subsequently
expanded, by a similar mechanism, to the diameter d2, by the
energised rollers 30.
Once the tubing 14 has been expanded as desired, the
rollers 30 may be retracted, and the tool 20 retrieved to
surface through the expanded tubing.
Those of skill in the art will recognise that further
operations will then be carried out, for example the
expanded tubing rrtay then be cemented and the second section
CA 02491963 2005-01-11
14b perforated.
Those of skill in the art will also recognise that
this embodiment is merely exemplary of the present
invention and that various modifications may be made
5 thereto without departing from the scope of the invention.
For example, the abovedescribed example features only two
sections of tubing of two different diameters. In other
=examples, three or more sections of tubing of three or more
different diameters might be provided. Alternatively, the
10 diameter of the tubing may progressively increase over a
section of tubing to form a tapering or flared bore_
Furthermore, any appropriate.form of expandable tubing and
expansion tool or mechanism may be utilised, depending on
the application.
Reference is now made to Figures 4 and 5 of the
drawings, which illustrate the creation of a lined bore in
accordance with a further embodiment of the invention.
Figure 4 illustrates an upper end of a drilled bore 40
within which 9 5/8" casing 42 has been located and
cemented. In this example, the casing 42 has a inner
diameter (i.d.) of 8.5"_ A length of 29 lb/ft 7 5/8" (i.d.
6.8") casing 44 has then been run into the bore 40, such
that the upper end of the casing 44 overlaps the lower end
of the casing 42. The casing 44 has then been expanded,
with the section of the casing 94 e.xtending below the
existing casing 42 being expanded to provide an i.d.
CA 02491963 2005-01-11
11
similar to that of the casing 42, that is 8_5". However,
at the overlap 46 between the casings 42, 44, the casing 44
can only be expanded to an outer diameter corresponding to
the inner diameter of the existing casing 42; the casing 42
has been cemented and thus cannot be expanded_ Thus, at
the overlap 46, the inner diameter of the throughbore
defined by the existing casing 42 and the expanded casing
44 is reduced by twice the thickness of the casing wall,
that is twice 3/8", to 7.75".
The expanded casing 44 is cemented in the drilled
bore, either prior to or following expansion. The
expansion of the casing is achieved using a compliant
expansion device, such as a fluid pressure actuated device
as described above, or alternatively an expandable cone,
which has the ability to expand the casing to the two
different diameters, and be withdrawn through the smaller
diameter overlap 46_
Figure 4 also illustrates a further section of casing
48 being run into the bore through the section of the bore
already lined by the existing casing 42 and the expanded
casing 44. The casing 48 is identical to the unexpanded
casi.ng 44, and thus has an external diameter of 7 5/8"
(7_625"), and thus may pass through the overlap 46, which
has an internal diameter of 7.75"_
The casing 43 is run into the bore 40 until the upper
end of the casing 48 overlaps the lower end of the now
CA 02491963 2005-01-11
12
expanded, cemented casing 44. The casing 48 is then
expanded and cemented, in a similar manner to the casing
44, and as illustrated in Figure 5, then provides a further
section of lined bore with a major section of 8.5" i.d. and
a short section of 7.75" i. d_, at the overlap 50 between
the casing sections 44, 48.
A bore may thus be drilled and lined as described
above, with no loss of diameter as the bore is extended.
The loss of diameter at the overlaps 46, 50 is relatively
minor, and offers advantages in, for example, providing
ledges or profiles useful in locating tools and other
devices in the bore, and more than compensates for the
technical difficulties involved in expanding the casing
sections 42, 44 at the overlaps 46, 50; proposals to this
end include expanding the tubing before cementing, or
before the cement has set, or providing arrangements to
retain the lower end of the casing 42, 44 free of cement.
The upper end of the casing sections 44, 48 may be
provided with sealing and locking arrangements suitable to
provide a fluid tight and secure coupling at the overlaps
46, 50.
