Note: Descriptions are shown in the official language in which they were submitted.
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METHOD AND APPARATUS FOR INSTALLING CASING IN A BOREHOLE
BACKGROUND OF THE INVENTION
Field of the Invention
[001 J The present invention relates generally to the process of running in
casing into a
borehole. More particularly, relating to a method and apparatus for running in
casing into a
borehole by utilizing a previously installed casing as piston cylinder.
[002] In the recovery of formation fluids, such as oil, gas and mineral
deposits, the drilling
and completion of a well, whether it be vertical, deviated or horizontal,
plays a vital role in the
successful production of the formation fluids.
[003] In recent years the practice of drilling deviated and horizontal wells
have become
more desirable over vertical wells due to a higher production of formation
fluid. A deviated well
is termed as a wellbore that is not vertical. The term usually indicates a
wellbore intentionally
drilled away from vertical. A horizontal well is termed where the departure of
the wellbore from
vertical exceeds about 80 degrees. Note that some horizontal wells are
designed such that after
reaching true 90-degree horizontal, the wellbore may actually start drilling
upward. In such cases,
the angle past 90 degrees is continued, as in 95 degrees, rather than
reporting it as deviation from
vertical, which would then be 85 degrees. Because a horizontal well typically
penetrates a greater
length of the reservoir, it can offer significant production improvement over
a vertical well. The
operation of drilling deviated and horizontal wellbores is well known in the
art and will not be
discussed here.
[004] The rate of production or the amount of production of a well is directly
related to the
length in which the reservoir is penetrated. However, in deviated or
horizontal wells it becomes
increasingly difficult to run in casing as the length of the casing run in is
increased. To increase
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the length of casing run into the reservoir many prior art devices have been
implemented to
attempt to increase the length of casing run in. One such device is described
in U.S. Patent No.
6,868,913, of which its entirety is incorporated herein by reference.
SUMMARY OF THE INVENTION
[005] In accordance with the present invention, to provide an apparatus and
method to
increase the length of casing that can be run into a wellbore.
[006] In general, in one aspect, a method of running in casing into a borehole
having a
previously installed section of casing is provided. The method including the
steps of
(i) providing a piston assembly;
(ii) engaging the piston assembly with a casing string to be installed into
the borehole;
(iii) inserting the casing string with the engaged piston assembly into the
previously
installed section of casing; and
(iv) pressurizing the previously installed section of casing above the piston
assembly
with a fluid such that the piston assembly engaged with the casing string is
forced to translate
within the previously installed section of casing such that the casing string
is pressed into the
borehole.
[007] In general, in another aspect, a method of running in casing into a
borehole having a
previously installed section of casing is provided. The method includes the
steps of:
(i) providing a piston assembly;
(ii) engaging the piston assembly with a casing string to be installed into
the borehole;
(iii) inserting the casing string with the engaged piston assembly into the
previously
installed section of casing;
(iv) pressurizing the previously installed section of casing above the piston
assembly
with a fluid such that the piston assembly engaged with the casing string is
forced to translate
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within the previously installed section of casing such that the casing string
is pressed into the
borehole;
(v) equalizing pressure across said piston assembly; and
(vi) disengaging the piston assembly from the casing string.
[008] In general, in another aspect, an apparatus for running in casing into a
borehole
having a previously installed section of casing is provided The apparatus
includes a piston body
having a forward end including an adaptor sub and an opposite rearward end,
the piston body
defining a longitudinal bore formed axially therethrough. A mandrill is
slidably received within
the longitudinal bore through the rearward end and is slidable within the
longitudinal bore to a
first position and to a second position. The piston body having a radial
shoulder surface of a
diameter to correspond to an interior diameter of the previously installed
casing, such that when
the piston body is positioned within the previously installed casing a sealing
contact is made
between the radial shoulder surface of the piston body and the interior
surface of the previously
installed casing. The piston body further defining at least one blind port
hole formed
therethrough from an exterior surface forward of the radial shoulder surface
to the longitudinal
bore, and defining at least one annulus port hole formed therethrough from an
exterior surface
rearward of the radial shoulder surface to the longitudinal bore, and wherein
fluid
communication is established between the at least one blind port hole and the
at least one
annulus port hole when the mandrill is positioned in the second position.
[009] There has thus been outlined, rather broadly, the more important
features of the
invention in order that the detailed description thereof that follows may be
better understood and
in order that the present contribution to the art may be better appreciated.
[0010] Numerous objects, features and advantages of the present invention will
be readily
apparent to those of ordinary skill in the art upon a reading of the following
detailed description of
presently preferred, but nonetheless illustrative, embodiments of the present
invention when taken
in conjunction with the accompanying drawings. The invention is capable of
other embodiments
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and of being practiced and carned out in various ways. Also, it is to be
understood that the
phraseology and terminology employed herein are for the purpose of
descriptions and should not
be regarded as limiting.
[0011] As such, those skilled in the art will appreciate that the conception,
upon which this
disclosure is based, may readily be utilized as a basis for the designing of
other structures,
methods and systems for carrying out the several purposes of the present
invention. It is
important, therefore, that the claims be regarded as including such equivalent
constructions
insofar as they do not depart from the spirit and scope of the present
invention.
[0012] For a better understanding of the invention, its operating advantages
and the specific
objects attained by its uses, reference should be had to the accompanying
drawings and
descriptive matter in which there is illustrated preferred embodiments of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The invention will be better understood and objects other than those
set forth above
will become apparent when consideration is given to the following detailed
description thereof.
Such description makes reference to the annexed drawings wherein:
[0014] Figure 1 is a schematic view of a conventional land well casing
architecture;
[0015] Figure 2 is a schematic view of the preferred embodiment of the
apparatus for running
in production casing constructed in accordance with the principles of the
present invention;
[0016] Figure 3 is a partial cross-sectional view of the apparatus positioned
within a
previously installed casing with the mandrill in the first downward position;
and
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[0017] Figure 4 is a partial cross-sectional view of the apparatus positioned
within a
previously installed casing with the mandrill in the second upward position.
[0018] The same reference numerals refer to the same parts throughout the
various figures.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Referring now to the drawings, and particularly to Figures 1-4, a
preferred embodiment
of the apparatus of the present invention is shown and generally designated by
the reference
numeral 10.
[0020] In Figure 1, a schematic diagram of a typical well 100 is shown. The
well 100
includes sections of casing 102 installed into concentric wellbores 104, such
as a conductor
casing 106, a surface casing 108 and an intermediate casing 110. It should be
appreciated the
term casing used herein also includes liners or any other form of a tubular
member. The casing
102 extend to varying depths according to the engineering of the well 100 and
particularly to the
different formations through which the wellbores 104 extend. The well 100
further includes a
deviated or horizontal wellbore 109 into which a production casing string 112
is being run in.
[0021] With reference to Figure 2, an apparatus 10, constructed in accordance
with the
present invention, is shown engaged with the casing string 112 and positioned
within a
previously installed section of casing, such as the intermediate casing 110.
The casing string 112
is generically illustrated for exemplary purposes only. The apparatus 10 is a
piston assembly 10
including a piston body 12 having a forward end 14 and a rearward end 16. The
piston body 12
further defines a radial shoulder surface 18, which is of a diameter to
correspond to the LD. of
the intermediate casing 110 such that a sealing contact is made between the
radial shoulder
surface and the intermediate casing. The radial shoulder surface 18 includes a
wear surface 20
and a sealing surface 22.
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[0022] To aid in centralizing the piston assembly 10, a centralizing member
114 can be
engaged with the casing string 112, and depending upon where the piston
assembly 10 is
engaged along the casing string 112, a centralizing member can be used forward
and rearward of
the piston assembly. The centralizing member 114 is a mechanical device to
position casing
concentrically in a wellbore. Usable centralizing members 114 are well known
in the art and do
not need to be described herein.
[0023] Preferably, the piston assembly 10 is engaged with the casing string
112 between the
liner hanger, not shown but well known in the art, from which production
casing depends (not
shown) and the second to the last joint of pipe, in the casing string,
required to land the liner
hanger in its engineered well position within the intermediate casing 110.
[0024] Now with reference to Figures 3 and 4, a partial cross-section of the
piston assembly
engaged with the casing string 112 and positioned within the intermediate
casing 110 is
shown. The piston assembly 10 further includes a mandrill 24 and an adaptor
sub 26. The
adaptor sub 26 and the mandrill 24 allow connection of the piston assembly 10
with casing string
112. The mandrill 24 is slidably received through the rearward end 16 of the
piston body 12 by a
longitudinal bore 28. The mandrill 24 is positionable in a first forward
position as shown in
Figure 3 and in a second rearward position as shown in Figure 4. The mandrill
24 is positioned
in the first forward position during running in of the casing string 112 and
then positioned in the
second rearward position upon completion of running in the casing string. The
mandrill 24 when
positioned in the first forward position, as shown in Figure 3, the first end
30 thereof is engaged
with the adaptor sub 26 as shown. Preferably, the first end 30 of the mandrill
24 is threadably
engaged with the adaptor sub 26.
[0025] The piston body 12 further defines at least one blind port hole 32
formed therethrough
from an exterior surface 33 forward of the radial shoulder surface 18 to the
longitudinal bore 28,
and at least one annulus port hole 34 formed therethrough from an exterior
surface 35 rearward
of the radial shoulder surface to the longitudinal bore. Preferably, four
blind port holes 32 and
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four annulus port holes 34 are formed through the piston body 12 radially
therearound and offset
at 90 degrees. The blind port holes 32 and the annulus port holes 34 a
restricted from fluidic
communication when the mandrill 24 is in the first forward position, as shown
in Figure 3, and
are in fluidic communication when the mandrill is in the second rearward
position, as shown in
Figure 4.
[0026] The piston assembly 10 further includes at least one projection 36
extending into the
longitudinal bore 28 approximate the rearward end 16 of the piston body 12.
Preferably, there
are two opposed projections 36. Most preferably, there are four projections 36
spaced radially
around the rearward end 16. The projections 36 can be spaced radially around
the rearward 16 at
an offset of 90 degrees.
[0027] A cooperating slot 38 formed longitudinally along the exterior surface
39 of the
mandrill 24 receives each projection 36. Each slot 38 is formed along the
exterior surface 39 of
the mandrill 24, such that when the mandrill is in the first forward position,
each projection 36 is
free from engagement with the cooperating slot 38 and the mandrill is free to
rotate about its axis
within the longitudinal bore 28. And such that when the mandrill 24 is in the
second rearward
position, each projection 36 is engaged with the cooperating slot 38 and the
mandrill is
rotationally locked with the piston body 12.
[0028] A piston body 12 further defines at least one longitudinal passage 40
or channel
formed through the radial shoulder surface 18 from the annulus side or
rearward side of the radial
shoulder surface to the blind or forward side of the radial shoulder surface.
A check valve 42 is
fitted within each passage 40 and allows fluid to flow from the blind side of
the radial shoulder
surface to the annulus side of the radial shoulder surface when pressure
within the intermediate
casing on the annulus side is below a predetermined value.
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[0029] Additionally a plurality of O-ring seals 44 can be positioned along the
longitudinal
bore 28 to providing sealing between the mandrill 24 and the interior surface
of the longitudinal
bore.
[0030] In use, it can now be understood, the piston assembly 10 is engaged or
otherwise
installed inline in the casing string 112 between the casing hanger from which
the casing to be
installed depends and the second to the last joint of casing string pipe
required to land the liner
hanger in its engineered well position.
[0031] The casing string 112 with the engaged piston assembly 10 is inserted
into the
intermediate casing 110 using surface equipment well known in the art to a
predetermined point.
The casing string 112 can be inserted into the intermediate casing to the
predetermined point
through such methods as gravity feeding or floating, both well known in the
art. While these two
methods are mentioned, it should be appreciated that other methods can be used
to insert the
casing string 112. During this process, fluid is free to flow from the blind
side of the piston body
12 to the annulus side of the piston body through the passages 40.
[0032] Once the casing string 112 with the engaged piston assembly 10 is
inserted to the
predetermined point, the intermediate casing 110 above the radial shoulder
surface 18 is
pressurized with a fluid, such a drilling fluid. The intermediate casing 110
can be pressurized
with drilling fluid through known techniques and equipment. One such technique
that is possible
is through the use of drilling fluid pump connected to a source of drilling
fluid and to the
wellhead through a kill line and other conventional equipment.
[0033] The pressurization of the intermediate casing 110 creates a pressure
differential across
the piston assembly 10 and forces the piston assembly, which is engaged with
the casing string
112, to translate through the intermediate casing and into the wellbore 110,
thereby pressing
production casing attached to the casing string 112 into the wellbore.
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[0034] Once the casing string 112 has reached a position within the
intermediate casing 110
that facilitates landing of the production casing to the intermediate casing,
the intermediate
casing is depressurized. The pressure cross the piston assembly is then
equalized by establishing
the blind port holes 32 in fluidic communication with the annulus port holes
34 by moving the
mandrill 24 from the first forward position to the second rearward position.
Once pressure is
equalized across the piston assembly 10, the piston assembly is backed off
from the installed
production casing and withdrawn from the well 100 using known methods.
[0035] A number of embodiments of the present invention have been described.
Nevertheless, it will be understood that various modifications may be made
without departing
from the spirit and scope of the invention. Accordingly, other embodiments are
within the scope
of the following claims.
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