U.S. patent application number 11/222356 was filed with the patent office on 2007-03-08 for retrievable frac packer.
This patent application is currently assigned to Eagle Downhole Solutions, LLC. Invention is credited to Jason E. Fike, Jabian P. Trahan, Kevin O. Trahan.
Application Number | 20070051521 11/222356 |
Document ID | / |
Family ID | 37829000 |
Filed Date | 2007-03-08 |
United States Patent
Application |
20070051521 |
Kind Code |
A1 |
Fike; Jason E. ; et
al. |
March 8, 2007 |
Retrievable frac packer
Abstract
A retrievable frac packer is provided which allows frac
operations to be conducted with a single, retrievable tool, with
the capability of providing positive zone production indications
during production testing.
Inventors: |
Fike; Jason E.; (Farmington,
NM) ; Trahan; Kevin O.; (The Woodlands, TX) ;
Trahan; Jabian P.; (Humble, TX) |
Correspondence
Address: |
R. PERRY MCCONNELL, P.C.
9001 FOREST CROSSING, SUITE F
THE WOODLANDS
TX
77381
US
|
Assignee: |
Eagle Downhole Solutions,
LLC
|
Family ID: |
37829000 |
Appl. No.: |
11/222356 |
Filed: |
September 8, 2005 |
Current U.S.
Class: |
166/387 ;
166/120 |
Current CPC
Class: |
E21B 33/1294 20130101;
E21B 23/06 20130101 |
Class at
Publication: |
166/387 ;
166/120 |
International
Class: |
E21B 33/12 20060101
E21B033/12; E21B 23/00 20060101 E21B023/00 |
Claims
1. A selectively settable and retrievable frac packer for use
inside an annular tube having an inner surface, comprising an
annular body comprising a selectively settable and releasable
circumferential seal, a selectively settable and releasable latch,
wherein said latch has a latched position which restrains said
circumferential seal in sealing engagement with the inner surface
of the annular tube and an unlatched position which releases said
seal, and a first valve which selectively controls fluid flow
through the annulus of said annular body.
2. The frac packer of claim 1, wherein said latch is wireline
settable.
3. The frac packer of claim 1, wherein said latch is hydraulically
settable.
4. The frac packer of claim 1, wherein said latch is settable by
tubing-conveyed means.
5. The frac packer of claim 1, wherein said latch is mechanically
settable.
6. The frac packer of claim 1, wherein said latch is settable by a
combination of hydraulic and mechanical action.
7. The frac packer of claim 1, additionally comprising selectively
settable and releasable frictional contact between said annular
body and the inner surface of the annular tube.
8. The frac packer of claim 7, wherein said frictional contact
comprises a slip.
9. The frac packer of claim 7, wherein the position of said latch
additionally controls the position of said frictional contact.
10. The frac packer of claim 1, additionally comprising a
mechanical bias device to assist in releasing said circumferential
seal when said latch is moved from its latched position to its
unlatched position.
11. The frac packer of claim 7, additionally comprising a
mechanical bias device to assist in releasing said circumferential
seal and said frictional contact when said latch is moved from its
latched position to its unlatched position.
12. The frac packer of claim 10, wherein said mechanical bias
device is a spring.
13. The frac packer of claim 11, wherein said mechanical bias
device is a spring.
14. The frac packer of claim 1, additionally comprising a second
valve which selectively controls fluid flow through the annulus of
said annular body.
15. The frac packer of claim 1, additionally comprising a
selectively releasable flagging media within the annulus of said
annular body.
16. The frac packer of claim 1, additionally comprising a connector
capable of selectively engaging a second frac packer for
simultaneous retrieval of both said frac packer and said second
frac packer.
17. A method of using a frac packer in a wellbore, comprising
lowering said frac packer to the desired depth, selectively setting
seals on said frac packer to isolate the wellbore above said frac
packer from the wellbore below said frac packer, selectively
controlling fluid flow through said frac packer, selectively
releasing said seals, and retrieving said frac packer from the
wellbore.
18. The method of claim 17, additionally comprising the step of
selectively allowing flow in one direction through said frac
packer.
19. The method of claim 17, wherein the step of retrieving said
frac packer additionally comprises the step of retrieving a second
frac packer from the wellbore on the same tool string.
20. The method of claim 17, wherein the step of retrieving said
frac packer additionally comprises the step of retrieving multiple
additional frac packers from the wellbore on the same tool
string.
21. The method of claim 17, additionally comprising the step of
selectively releasing a flagging media from said frac packer.
Description
FIELD OF THE INVENTION
[0001] The invention relates to frac packers which can be used in
downhole environments, retrieved, and reconditioned for further use
rather than requiring the time and expense to drill out, and thus
destroy, the tool after use.
BACKGROUND OF THE INVENTION
[0002] To "frac" a well involves the introduction of media,
typically containing a proppant, into a zone surrounding the
wellbore to create flow conduits in the surrounding earth. In the
interest of cost reduction, it is desirable to carry out such an
operation as quickly as possible, and with as few trips up and down
the wellbore as possible. For frac operations, it is necessary to
introduce a seal in the wellbore to prevent the frac fluid from
travelling further downhole than the desired frac zone.
[0003] However, wells often have multiple production zones as well
as multiple zones where performing the frac operation is desirable.
Therefore, the seal which is introduced into the wellbore must be,
or is certainly preferably, removable to allow free communication
with the wellbore below. Various combinations of devices have been
used to accomplish these goals. For example, drillable frac packers
are used which allow a single tool to perform the needed tasks.
However, these tools require expensive surface support equipment in
order to be drilled out after the frac operation is completed.
Drilling out such tools is time consuming, and therefore expensive,
and can result in undesirable damage to the inside of the wellbore.
Further, tool cost using this approach is driven up because the
tools themselves must be considered as expendable.
[0004] Another approach is to use a packer in combination with a
separate, retrievable bridge plug, with the two tools straddling
the frac zone. However, such an approach requires two separate
tools to perform a single task, adding cost and complexity to the
process. Accordingly, it is desirable to provide a single,
retrievable frac packer tool, which can be reconditioned and reused
rather than being used once and being destroyed.
[0005] Further, because these tools are often used in wells with
multiple frac zones, it is desirable to provide a frac tool which
provides bi-directional flow control, thereby providing the
capability of not only sealing off the well down-hole of the packer
from pressure from above during the frac operation, but also
allowing flow from below to be selectively closed off. It is
further desirable to provide such tools with flagging media, such
as dyes, so that tools used in different frac zones may contain
differentiating markings within the flagging media, and thus
provide the surface operators with confirmation of the existence of
production flow at different levels in the wellbore.
[0006] The interests of keeping costs down additionally makes it
desirable to provide a retrievable frac packer which is
sufficiently compact and lightweight to allow it to be run-in on
wireline, coiled tubing, or other deployment methods and which has
the flexibility to be settable either by wireline, hydraulic
pressure, or other setting methods, including combinations of
hydraulic and mechanical methods.
[0007] Accordingly, it is an object of the invention to provide a
retrievable frac packer which provides a single-tool capable of
allowing the frac operation to proceed, but which may be retrieved
and reconditioned for repeated use.
[0008] It is a further object of the invention to provide such a
tool that can also be retrieved in groups of two or more tools at a
time, reducing the number of downhole trips required to retrieve
the tools when there are multiple frac zones in a well.
[0009] It is another object of the invention to provide a
retrievable frac packer that provides bidirectional flow
control.
[0010] It is yet another object of the invention to provide a
retrievable frac packer that can provide confirmation to surface
operators of the downhole level or levels which are producing
product flow.
[0011] It is still a further object of the invention to provide a
retrievable frac packer which can be run-in on wireline, coiled
tubing, or another type of tool string, and which can be set by
either wireline, hydraulic methods, or other setting methods.
SUMMARY OF THE INVENTION
[0012] The invention is a frac packer that comprises an annular
body comprising a circumferential seal that can be set by
compression. When the tool is run downhole, the seal is in the
"un-set" position, allowing clearance between the tool and the
surrounding casing. A check valve is provided within the annular
body to preclude downhole flow of fluid through the tool once the
tool is set in the desired position.
[0013] At the desired depth, the tool is set by wireline control,
hydraulic pressure, mechanical means, or a combination of these
techniques to compress and engage the circumferential seal with the
inner wall of the surrounding casing. Compression pressure is
applied to the seals by an upper compression member in slidable
engagement with the annular body of the tool, and by a lower
compression member in slidable engagement with the annular body of
the tool. Downward travel of the lower compression member may be
resisted by mechanical stops. However, in the preferred embodiment,
the lower compression member is biased upward by mechanical means,
such as a spring, to provide improved sealing force and to assist
in the release of the tool after the frac operation. If the tool is
to be utilized in wells in which multiple tools will be retrieved
simultaneously, such a mechanical biasing is necessary to insure
that the tools will release properly and move further down the
wellbore to retrieve a deeper set frac packer, and retrieve
properly.
[0014] A slip is preferably present in slideable engagement with
the annular body of the tool on the downhole side of the seal, so
that the compression setting of the tool also activates the slip
into locking engagement with the casing in the wellbore, thus
securing the tool against slippage within the casing before,
during, or after the frac operation.
[0015] Once compressed into sealing engagement with the well
casing, the position of the upper compression member relative to
the annular body of the tool is locked by a selectively releasable
latch, such as a ratcheting mechanism, so that the seal is held in
sealing engagement with the well casing during the frac operation.
Release of the latch is preferably accomplished by mechanical
means, such as a shear means, like studs or screws, so that the
tool may be released from its sealing engagement with the well
casing by a jarring effect or other mechanical force controllable
from the surface.
[0016] Inside the annulus of the annular body of the tool, a first
check valve is positioned to allow fluid flow from the downhole end
of the tool upward, but not from the uphole end of the tool
downward. Thus, flow can be allowed through the tool from below if
necessary, while simultaneously sealing the environment downhole of
the tool from pressure above the tool during the frac
operation.
[0017] The tool may also be configured with a second check valve
positioned in opposed configuration to and uphole of the first
check valve, creating a region within the annulus of the tool
through which no flow may occur. This second check valve preferably
comprises a degradable ball seal, which will degrade at a
calculated time to allow upwardly-directed flow through the tool,
or a mechanically releasable seal which will open when frac
pressure reaches the tool.
[0018] In conjunction with such a second check valve, the tool may
be configured with a flagging media, such as a dye package, so that
when flow begins through the tool the flagging media will be
released to flow to the surface. In this configuration, multiple
tools with differently-marked flagging media may be used in
multiple commingled production zones to provide confirmation at the
surface of which of the commingled zones are flowing.
[0019] In the preferred embodiment, the downhole end of the annular
body of the tool is provided with a grip capable of latching onto
the uphole end of another of such tools. Thus, when frac operations
are completed in a wellbore with multiple zones, each tool may be
released in turn, then moved downhole to latch onto and release the
next lower tool. In this way, multiple tools may be retrieved
simultaneously, reducing the number of trips required to clear the
tools from the wellbore.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1A is a sectional view of one embodiment of the
retrievable frac packer of the present invention in the run-in
position.
[0021] FIG. 1B is a sectional view of the embodiment depicted in
FIG. 1A, with an optional flagging media package added.
[0022] FIG. 1C is a sectional view of the embodiment depicted in
FIG. 1A, with a second check valve incorporated.
[0023] FIG. 2A is sectional view of an alternative embodiment of
the retrievable frac packer depicted in FIG. 1A, with the first
check valve replaced with an alternative sliding sleeve and sealing
ball valve.
[0024] FIG. 2B is an expanded sectional view of the alternative
check valve of FIG. 2A, with the sliding sleeve of the valve in its
initial position.
[0025] FIG. 2C is an expanded sectional view of the alternative
check valve of FIG. 2A, with the sliding sleeve of the valve in its
final position.
[0026] FIG. 3A is a sectional view of the retrievable frac packer
of FIG. 1C, shown in the set position.
[0027] FIG. 3B is a sectional view of the retrievable frac packer
of FIG. 3A, shown with the degradable ball having dissolved and
with flow occurring through the tool.
DETAILED DESCRIPTION
[0028] Referring to FIGS. 1A and 1B, one embodiment of the
retrievable frac packer of the present invention is shown. The
retrievable frac packer 10 comprises an annular body 12, which can
be run-in to an appropriate position in a well casing 14.
Compressible seal 16 is positioned to be placed into sealing
engagement with the inner wall 18 of the well casing 14. Upper
compression member 20 is moveable by wireline control, hydraulic
setting means, or a combination of hydraulic and mechanical means
(not shown) to force upper linkage 22 downward against the
compressible seal 16.
[0029] Such movement will also force lower compression member 24
downward, compressing mechanical biasing spring 26, and applying
upward force against compressible seal 16. The downward movement of
lower compression member 24 also will force slip 28 outward into
mechanical engagement with the inner wall 18 of the well casing
14.
[0030] Downward movement of upper compression member 20 also
engages latch 30 into a locking position by moving ratchet arm 32
into locking engagement with ratchet base 34. Spring 36 applies
biasing force to aid in holding ratchet arm 32 into a locked
position once set. Sliding push sleeve 37 allows the downward force
to be transmitted to seal base sleeve 39 through a path other than
through shear means 38, protecting shear means 38 from excessive
force during the setting operation.
[0031] When release of the retrievable frac packer 10 from its set
position is desired, an upward jar may be applied, shearing shear
means 38. This in turn will allow the upward movement of upper
linkage 22, which interlocks with ratchet arm 32, thus releasing
latch 30 and allowing upper compression member 20 to move upward.
Bias force from compression spring 26 further assists in this
upward movement, relieving pressure against compressible seal 16
and allowing slip 28 to release its mechanical engagement with the
inner wall 18 of well casing 14.
[0032] First check valve 42 allows the retrievable frac packer 10
to protect the region below from hydraulic pressures above so that
frac operations may proceed. However, first check valve 42 also
allows flow testing of the well to occur without removing the
retrievable frac packer 10 from the well. For such purposes, a
flagging media such as dye pack 44 may be carried downhole within
the annulur body of the retrievable frac packer 10. In a multiple
production zone well, multiple retrievable frac packers 10 may be
inserted into different production zones with uniquely-marked
flagging media, providing confirmation on the surface of which
zones are flowing.
[0033] Referring to FIG. 1C, an alternative embodiment of the
retrievable frac packer 10 is shown incorporating a second check
valve 46. In this embodiment, second check valve 46 incorporates a
degradable ball 48, allowing the retrievable frac packer 10 to be
run in to the well as a bridge plug. After a calculated time in the
well environment, the degradable ball 48 will dissolve, allowing
the retrievable frac packer 10 to operate as described above.
[0034] Referring to FIG. 2, an alternative embodiment of the
retrievable frac packer 10 of FIGS. 1A-1C is shown. First check
valve 42 of FIG. 1 is replaced by a sliding sleeve valve 242. For
run-in, sliding sleeve valve 242 seals in both directions, and
allows retrievable frac packer 210 to be run-in as a bridge plug.
Once in position, hydraulic pressure may be applied, for example,
at the same time frac operations are conducted above the
retrievable frac packer 210, sliding sleeve 250 into an open
position 252 and allowing sliding sleeve valve 242 to function in
the same manner as first check valve 42 of FIG. 1.
[0035] Referring now to FIGS. 3A and 3B, retrievable frac packer
310 is shown in the set position. Upper compression member 320 has
been moved downward relative to the annular body 312 of retrievable
frac packer 310. Compressible seal 316 is in sealing contact with
the inner wall 318 of the well casing 314. Latch 330 is set by the
interlocking of ratchet arm 332 with ratchet base 334, preventing
loss of compression force against compressible seal 316. Slip 328
is also forced outward into mechanical engagement with the inner
wall 318 of well casing 314, resulting from the downward movement
of lower compression member 324 relative to the annular body 312 of
retrievable frac packer 310.
[0036] As shown in FIG. 3A, the initial setting of retrievable frac
packer 310 allows frac operations to proceed. First check valve 342
and compressible seal 316 prevent fluid flow downhole of the
retrievable frac packer 310 during frac operations. After the
degradable ball 348 has dissolved, second check valve 346 "opens,"
and flow may be tested prior to removal of the retrievable frac
packer 310, as shown in FIG. 3B. Upward flow pressure opens first
check valve 342, allowing test production flow to proceed up the
wellbore.
[0037] The above examples are included for demonstration purposes
only and not as limitations on the scope of the invention. Other
variations in the construction of the invention may be made without
departing from the spirit of the invention, and those of skill in
the art will recognize that these descriptions are provide by way
of example only.
* * * * *