U.S. patent application number 11/675134 was filed with the patent office on 2008-08-21 for reverse circulation cementing valve.
Invention is credited to Daniel Bour, Aimee Greening.
Application Number | 20080196889 11/675134 |
Document ID | / |
Family ID | 39705657 |
Filed Date | 2008-08-21 |
United States Patent
Application |
20080196889 |
Kind Code |
A1 |
Bour; Daniel ; et
al. |
August 21, 2008 |
Reverse Circulation Cementing Valve
Abstract
A method for reverse cementing may include providing a valve
having a sliding sleeve, an outer sleeve situated about at least a
portion of the sliding sleeve and connected to a casing string, and
a spring configured to position the valve in an open position. The
method may also include: running the casing string and valve into a
well bore while the valve is in an open position; reverse
cementing, while the valve is in an open position; and closing the
valve after reverse cementing by allowing the valve to contact the
well bore.
Inventors: |
Bour; Daniel; (Bakersfield,
CA) ; Greening; Aimee; (Duncan, OK) |
Correspondence
Address: |
John W. Wustenberg;Halliburton Energy Services, Inc.
2600 S. 2nd Street, P. O. Box 1431
Duncan
OK
73536
US
|
Family ID: |
39705657 |
Appl. No.: |
11/675134 |
Filed: |
February 15, 2007 |
Current U.S.
Class: |
166/250.14 ;
166/333.1 |
Current CPC
Class: |
E21B 33/14 20130101;
E21B 21/10 20130101 |
Class at
Publication: |
166/250.14 ;
166/333.1 |
International
Class: |
E21B 33/05 20060101
E21B033/05 |
Claims
1. A method for reverse cementing, comprising: providing a valve
comprising a sliding sleeve, an outer sleeve situated about at
least a portion of the sliding sleeve and connected to a casing
string, and a spring configured to position the valve in an open
position; running the casing string and valve into a well bore
while the valve is in an open position; reverse cementing, while
the valve is in an open position; and closing the valve after
reverse cementing by allowing the valve to contact the well
bore.
2. The method for reverse cementing of claim 1, wherein closing the
valve after reverse cementing comprises allowing the valve to
contact the bottom of the well bore.
3. The method for reverse cementing of claim 1, further comprising:
pumping a tracer fluid ahead of the cement.
4. The method for reverse cementing of claim 1, further comprising:
allowing the cement to bond to the casing string.
5. The method for reverse cementing of claim 1, further comprising:
closing the valve prior to reverse cementing by allowing the valve
to contact the well bore; and reopening the valve prior to reverse
cementing.
6. The method for reverse cementing of claim 5, wherein closing the
valve prior to reverse cementing comprises allowing the valve to
contact the bottom of the well bore.
7. The method for reverse cementing of claim 5, wherein the valve
further comprises a latch mechanism and wherein reopening the valve
comprises applying pressure on the inside of the casing string.
8. The method for reverse cementing of claim 5, wherein reopening
the valve comprises removing weight from the casing string.
9. A valve for reverse cementing, comprising: a sliding sleeve
having one or more openings; a nose attached to sliding sleeve; an
outer sleeve situated about at least a portion of the sliding
sleeve; and a spring configured to position the sliding sleeve such
that fluid may pass through the openings.
10. The valve for reverse cementing of claim 9, further comprising:
one or more flow passages in the outer sleeve; wherein the spring
is further configured to align the openings of the sliding sleeve
with the flow passages of the outer sleeve such that fluid may pass
therethrough.
11. The valve for reverse cementing of claim 9, further comprising
one or more centralizers to help prevent premature activation.
12. The valve for reverse cementing of claim 9, wherein the sliding
sleeve and the nose are constructed of drillable material.
13. The valve for reverse cementing of claim 9, further comprising
a latch mechanism.
14. The valve for reverse cementing of claim 13, wherein the latch
mechanism comprises a pin and a groove.
15. The valve for reverse cementing of claim 13, wherein the latch
mechanism is constructed such that it can be released without
damage.
16. A method for reverse cementing, comprising: providing a valve
comprising a sliding sleeve, an outer sleeve situated about at
least a portion of the sliding sleeve and connected to a casing
string; running the casing string and valve into a well bore while
the valve is in a closed position; opening the valve after running
the casing string by allowing the valve to contact the well bore;
reverse cementing, while the valve is in an open position; and
closing the valve after reverse cementing.
17. The method for reverse cementing of claim 16, further
comprising: pumping a tracer fluid ahead of the cement.
18. The method for reverse cementing of claim 16, further
comprising: allowing the cement to bond to the casing string.
19. The method for reverse cementing of claim 16, wherein the valve
further comprises a latch mechanism and wherein closing the valve
comprises applying pressure on the inside of the casing string.
20. The method for reverse cementing of claim 19, wherein closing
the valve comprises removing weight from the casing string.
Description
BACKGROUND
[0001] Typically, after a well for the production of oil or gas has
been drilled, casing is lowered and cemented into the well bore.
Normal primary cementing of the casing string in the well bore
includes lowering the casing to a desired depth and displacing a
desired volume of cement down the inner diameter of the casing.
Cement is displaced downward into the casing until it exits the
bottom of the casing into the annular space between the outer
diameter of the casing and the well bore apparatus. This method may
present numerous challenges, including difficulty getting
circulation inside of the annular space due to weak formations. Not
only does the hydrostatic weight of the cement exert pressure
against formations, but additional pressure is applied to
formations due to the friction of the fluid that must be
overcome.
[0002] One method to help reduce the formation pressure is to pump
fluids down the annulus and back up through the casing, often
called "reverse circulation" or "reverse cementing." The
reverse-cementing method comprises displacing conventionally mixed
cement into the annulus between the casing string and the annulus
between an existing string, or an open hole section of the well
bore. As the cement is pumped down the annular space, drilling
fluids ahead of the cement are displaced around the lower ends of
the casing string and up the inner diameter of the casing string
and out at the surface. The fluids ahead of the cement may also be
displaced upwardly through a work string that has been run into the
inner diameter of the casing string and sealed off at its lower
end. Because the work string has a smaller inner diameter, fluid
velocities in the work string will be higher and will more
efficiently transfer the cuttings washed out of the annulus during
cementing operations. To ensure that a good quality cement job has
been performed, a small amount of cement will be pumped into the
casing and the work string. As soon as a desired amount of cement
has been pumped into the annulus, the work string may be pulled out
of its seal receptacle and excess cement that has entered the work
string can be reverse-circulated out the lower end of the work
string to the surface.
[0003] Reverse cementing, as opposed to the conventional method,
provides a number of advantages. For example, cement may be pumped
until a desired quality of cement is obtained at the casing shoe.
Furthermore, cementing pressures are much lower than those
experienced with conventional methods and cement introduced in the
annulus free-falls down the annulus, producing little or no
pressure on the formation. Oil or gas in the well bore ahead of the
cement may be bled off through the casing at the surface. Finally,
when the reverse-cementing method is used, less fluid is required
to be handled at the surface and cement retarders may be utilized
more efficiently.
[0004] While reverse-cementing can greatly reduce the total
pressure applied to the formation, it has some drawbacks. First, it
is difficult to know exactly when the cement has been circulated
into the casing. In some instances a wire line tool is placed
downhole to determine when radioactive tracers or changes in fluid
properties occur, thus providing an indication of when the cement
has completely filled the annulus and begun to enter the casing.
Another technique is to use a volumetric method involving the
monitoring of fluid volumes returning to the surface and estimating
when the cement has filled the annulus. If, however, this method is
attempted while cementing an annulus between the casing and
formation that been drilled out, there can be a large uncertainty
about the actual annular hole volume. This may result in incomplete
filling of the annulus with cement, or it may result in overfilling
the annulus and getting cement back up inside the casing string.
This cement inside the casing string may cover potential productive
zones and/or require additional rig time to drill out. Another
challenge to reverse circulation is the problem of effective float
equipment that keeps the typically heavier cement from flowing
inside the casing due to U-Tubing. Because the fluids are pumped
reverse, conventional float equipment cannot be used. This means
that after a reverse cement job, pressure must be held on the
inside of the casing until the cement has sufficiently set to
prevent this U-Tubing. This can cause a micro-annulus to form
between the cement sheath and casing, which makes it difficult to
bond log the casing to evaluate the quality of the cement job and
determine if the annulus is properly sealed.
SUMMARY
[0005] The present invention relates generally to reverse
cementing. More specifically, the present invention is directed to
a valve that may be used in reverse cementing operations.
[0006] In one embodiment of the present invention, a method for
reverse cementing comprises: providing a valve comprising a sliding
sleeve, an outer sleeve situated about at least a portion of the
sliding sleeve and connected to a casing string, and a spring
configured to position the valve in an open position. The method of
this embodiment further comprises: running the casing string and
valve into a well bore while the valve is in an open position;
reverse cementing, while the valve is in an open position; and
closing the valve after reverse cementing by allowing the valve to
contact the well bore.
[0007] In another embodiment of the present invention, a valve for
reverse cementing comprises: a sliding sleeve having one or more
openings; a nose attached to sliding sleeve; an outer sleeve
situated about at least a portion of the sliding sleeve; and a
spring configured to position the sliding sleeve such that fluid
may pass through the openings.
[0008] In still another embodiment of the present invention, a
method for reverse cementing comprises: providing a valve
comprising a sliding sleeve, an outer sleeve situated about at
least a portion of the sliding sleeve and connected to a casing
string. The method of this embodiment further comprises: running
the casing string and valve into a well bore while the valve is in
a closed position; opening the valve after running the casing
string by allowing the valve to contact the well bore; reverse
cementing, while the valve is in an open position; and closing the
valve after reverse cementing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a side view of a valve in accordance with one
embodiment of the present invention.
[0010] FIG. 2 is a side view showing another embodiment of the
valve in accordance with the present invention.
DETAILED DESCRIPTION
[0011] Referring now to FIGS. 1 and 2, valve 100 may be used in
reverse cementing applications. More specifically, valve 100 may be
attached at or near the bottom of casing string 102 via threaded
connection or otherwise. Valve 100 may be operated by simply
lowering casing string 102 until casing string 102 contacts a lower
end of well bore 106. This contact causes the weight of casing
string 102 to activate valve 100. This involves sliding sleeve 108
of valve 100 moving relative to outer sleeve 118 of valve 100.
Depending on the application, this may either open ports 116,
allowing fluid to flow from within casing string 102 to annulus 104
and visa versa, or it may close ports 116, preventing the flow of
fluid therethrough.
[0012] Valve 100 may include outer sleeve 118, which may have
threads 130 near an upper end for securing outer sleeve 118 to
casing string 102. Outer sleeve 118 and threads 130 may be sized
such that valve 100 may fit any of a number of different casing
strings, depending on the specific circumstances of the site.
Therefore valve 100 may be a shoe.
[0013] Additionally, valve 100 may include sliding sleeve 108
situated at least partially within outer sleeve 118. Sliding sleeve
108 may be moveable longitudinally with respect to outer sleeve
118. Sliding sleeve 108 may include nose 110 at an end opposite
outer sleeve 118. Nose 110 may be constructed such that it guides
valve 100 into well bore 106, without activating, yet easily
activates valve 100 when reaching the bottom of well bore 106. For
example, nose 110 may have a conical, rounded or other suitable
shape. Since drilling of the well bore 106 does not necessarily
stop at the exact point where casing string 102 ends, it may be
desirable to construct at least a portion of valve 100 of drillable
materials. For example sliding sleeve 108, including nose 110 may
be made of drillable materials, such as composites, phenolics,
metallics, or plastics, or any other drillable material. While
drillable materials may be desirable in certain applications, they
would not be necessary when drilling stops at the bottom of the
casing string 102.
[0014] Valve 100 may also include spring 120, which may be a
standard spring or any other type of compression member tending to
bias sliding sleeve 108 out of outer sleeve 118. Spring 120 may be
constructed of materials suitable for use in a typical downhole
environment. In the embodiment shown in FIG. 2, however, spring 120
is contained between sliding sleeve 108 and outer sleeve 118 and
sealed from annulus 104. This may allow spring 120 to compress
freely without being limited by contaminants. Additionally, it may
prevent rust or other reactions with fluids present in annulus
104.
[0015] Valve 100 may also include one or more seals 126 to reduce
or eliminate leakage through the valve. Seals 126 may be o-rings or
any other type of seal used in a downhole environment.
[0016] Since well bore 106 is not cased until after valve 100 has
passed through, valve 100 may include centralizer 128. Centralizer
128 may prevent nose 110 from catching on the formation prior to
reaching the bottom. Thus, centralizer 128 may help to prevent
premature activation.
[0017] Valve 100 also includes one or more ports 116 configured to
selectively allow fluid to flow from annulus 104 into casing string
102. In the embodiment of FIG. 1, ports 116 include flow passages
112 in outer sleeve 118, which may align with openings 114 in
sliding sleeve 108, creating a passage therethrough. In this
embodiment, flow passages 112 in the outer sleeve 118 must be
aligned with openings 114 in sliding sleeve 108, or ports 116 will
be closed. Alternatively, in the embodiment of FIG. 2, ports 116
only include openings 114 in sliding sleeve 108, with no
corresponding flow passages in outer sleeve 118. This embodiment
allows ports 116 to be open, so long as ports 116 are not
obstructed by outer sleeve 118. Openings 114 and flow passages 112
may be holes, slots, or any other type of opening allowing the
passage of fluid therethrough. Openings 114 and flow passages 112
may be radial to moveable sleeve 108 and casing string 102, or they
may tilt, depending on the specific application. Additionally, the
shape and/or orientation of openings 114 may differ from the shape
and/or orientation of flow passages 112. In some circumstances, the
total cross sectional area of ports 116 may be approximately equal
to the cross sectional area of casing string 102. However, one of
ordinary skill in the art will appreciate that the total cross
sectional area of ports 116 may be larger or smaller than the cross
sectional area of casing string 102. In some applications, the
minimum diameter of ports 116 may be about 1/4'' and the maximum
diameter of ports 116 may be several inches. In other applications,
the minimum diameter of ports 116 may be about 1/2'' and the
maximum diameter of ports 116 may be 1 1/2''. While circular ports
116 are disclosed, the ports 116 may be any shape.
[0018] In the embodiments shown, ports 116 are closed when spring
120 is compressed, such that at least a portion of sliding sleeve
108 moves into outer sleeve 118. As this happens, ports 116 close.
In the embodiment of FIG. 1, this happens when flow passages 112
are no longer aligned with openings 114. In the embodiment of FIG.
2, this happens when the portion of sliding sleeve 108 containing
openings 114 moves into outer sleeve 118. Spring 120 may be
compressed by weight on casing string 102. More particularly, after
nose 110 makes contact with the bottom of well bore 106, and casing
string 102 continues to be lowered, spring 120 compresses,
resulting in relative movement between sliding sleeve 108 and outer
sleeve 118. In some embodiments, removal of the compressing force
on spring 120 will result in ports 116 reopening.
[0019] Referring now to FIG. 2, as an alternative to reopening when
weight is removed, at least one latch mechanism may be provided to
maintain ports 116 in a closed position. Latch mechanism may be any
device or mechanism for preventing relative movement between
sliding sleeve 108 and outer sleeve 118. For example, but not by
way of limitation, the latch mechanism may include a spring loaded
pin 122, which engages groove 124. As spring 120 is compressed and
ports 116 are closed, pin 122 may align with groove 124. At least a
portion of pin 122 may engage groove 124, preventing sliding sleeve
108 from moving relative to outer sleeve 118. In the embodiment of
FIG. 2, pin 122 is shown in sliding sleeve 108 and grove 124 is
shown in outer sleeve 118. However, pin 122 and groove 124 could be
placed in opposite locations, or in any location that may prevent
relative movement between sliding sleeve 108 and outer sleeve
118.
[0020] When pin 122 and groove 124 are used, ports 116 may be
reopened by applying pressure on the inside of casing string 102.
This pressure will push downward on sliding sleeve 108 relative to
outer sleeve 118. While pin 122 and groove 124 may have a tendency
to prevent movement, sufficient pressure may cause pin 122 to
retract from groove 124, and thus allow sliding sleeve 108 to move
relative to outer sleeve 118, until ports 116 are reopened.
Therefore, pin 122 may be rounded or otherwise shaped such that it
does not completely and irreversibly engage groove 124. Likewise,
any other latch mechanism used may be constructed such that it can
be released without damage.
[0021] When casing string 102 and attached valve 100 are being run
into well bore 106, ports 116 may be held in an open position by
spring 120, allowing mud or other fluid to flow freely from annulus
104 into and through casing string 102. This is known as "auto
flow" and prevents casing string 102 from floating in the mud.
[0022] In some instances, it may be useful to reopen ports 116 that
have inadvertently closed. This may occur in any number of cases.
For example, nose 110 may "catch" on well bore 106 at a point above
the bottom. In one embodiment, ports 116 may be reopened by simply
removing weight from casing string 102. In another embodiment,
reopening ports 116 involves the application of pressure to the
inside of casing string 102.
[0023] After valve 100 reaches the bottom of well bore 106, weight
on casing string 102 may cause ports 116 to close, verifying that
valve 100 has reached the bottom. After ports 116 have closed as a
result of valve 100 reaching the bottom of well bore 106, ports 116
may be reopened. Fluids may be circulated in either the
conventional or reverse directions when ports 116 are open. Ports
116 may remain open until cement is reverse circulated in place. At
the end of the circulation of cement, casing string 102 and valve
100 may again be lowered until spring 120 compresses and ports 116
are closed. In one embodiment, pin 122 then engages groove 124 such
that ports 116 remain closed. This may allow for optimum bonding of
the cement to casing string 102. Additionally, it may allow normal
surface operations to take place while waiting for the cement to
set.
[0024] One of ordinary skill in the art will appreciate that the
elements for use in the embodiments described above may be used in
a manner that allows weight on casing string 104 to cause ports 116
to open. In other words, weight may cause sliding sleeve 108 to
move, such that ports 116 are open. Optional pins (not shown) may
be used to keep the ports 116 open. Ports 116 may then be closed by
removing the weight of casing string 102. Alternatively, ports 116
may be closed by doing a weight shift cycle on and off. Yet another
alternative is to close ports 116 with a "bomb" that is dropped
allowing for a pressuring up. Thus, a method for reverse cementing
may include: providing valve 100 including sliding sleeve 108,
outer sleeve 118 situated about at least a portion of sliding
sleeve 108 and connected to casing string 102, and spring 120
configured to position valve 100 in an open position. This method
may also include: running casing string 102 and valve 100 into well
bore 106 while valve 100 is in an open position; reverse cementing,
while valve 100 is in an open position; and closing valve 100 after
reverse cementing by one of several methods. The methods of closing
valve 100 may include, for example, setting weight down on casing
string 102 to close ports 116 or dropping a weighted plug (not
shown) that then can have pressure applied to close ports 116.
[0025] An alternative method for reverse cementing may include:
providing valve 100 including sliding sleeve 108, outer sleeve 118
situated about at least a portion of sliding sleeve 108 and
connected to casing string 102. This method may also include:
running casing string 102 and valve 100 into well bore 106 while
valve 100 is in an open position; reverse cementing, while valve
100 is in an open position; and closing valve 100 after reverse
cementing by dropping a weighted dart/bomb (not shown) that can
engage a closing mechanism (not shown) and then applying pressure
to move sliding sleeve 108 downward and close valve 100.
[0026] Valve 100 may be used in conjunction with wire line tools
and various fluid tags. Valve 100 may also be used by pumping a
tracer fluid ahead of the cement job. The tracer fluid can be
identified at the surface to determine when cement slurry, some
distance behind the leading edge of the tracer, will be entering
casing string 102. Valve 100 may also be used with a simple
volumetric method of pumping a predetermined amount of fluid and
stopping.
[0027] A variation of valve 100 may also be placed some distance
above the bottom of a tubing string assembly, allowing for
circulation of cement to a predetermined depth, and leaving well
bore 106 below free of cement.
[0028] One may also drill well bore 106 past a target production
zone, set casing below the target production zone, and then allow
for cement to circulate up into the casing, but not up across
production zones. This may reduce or eliminate the need to drill
out cement at the bottom for the casing string, if the method were
used on a final production casing cement job.
[0029] Therefore, the present invention is well adapted to attain
the ends and advantages mentioned as well as those that are
inherent therein. The particular embodiments disclosed above are
illustrative only, as the present invention may be modified and
practiced in different but equivalent manners apparent to those
skilled in the art having the benefit of the teachings herein.
Furthermore, no limitations are intended to the details of
construction or design herein shown, other than as described in the
claims below. It is therefore evident that the particular
illustrative embodiments disclosed above may be altered or modified
and all such variations are considered within the scope and spirit
of the present invention. Also, the terms in the claims have their
plain, ordinary meaning unless otherwise explicitly and clearly
defined by the patentee.
* * * * *