Information
-
Patent Grant
-
6382324
-
Patent Number
6,382,324
-
Date Filed
Tuesday, June 20, 200024 years ago
-
Date Issued
Tuesday, May 7, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Bagnell; David
- Gay; Jennifer H
Agents
- Fletcher, Yoder & Van Someren
-
CPC
-
US Classifications
Field of Search
US
- 166 237
- 166 2426
- 166 378
- 166 380
- 166 387
- 166 382
- 166 206
- 166 240
- 166 115
- 166 208
-
International Classifications
-
Abstract
A system for permitting deployment of a polished bore receptacle, seal stack and production tubing in a single downhole trip into a wellbore. The system includes a polished bore receptacle, production tubing, a seal stack disposed about the production tubing, and a one trip seal latch that couples the production tubing to the polished bore receptacle. The seal latch includes an outer latch housing and an inner latch housing. The outer housing and inner housing are connected by a releasable coupling device. Thus, the polished bore receptacle can be moved downhole for latching to a packer without insertion of the seal stack into the interior of the polished bore receptacle. Upon latching of the polished bore receptacle to the packer, the coupler may be selectively released to permit insertion of the seal stack into the polished bore receptacle.
Description
FIELD OF THE INVENTION
The present invention relates generally to the production of fluid from a wellbore, and particularly to a system that permits the deployment of a polished bore receptacle (PBR) and the corresponding seal stack with a single trip downhole.
BACKGROUND OF THE INVENTION
A variety of equipment and devices are used in downhole, wellbore environments. In certain applications, production tubing is coupled to a packer via a polished bore receptacle that receives a seal stack disposed at the downhole end of the production tubing.
For example, a packer may be disposed within a wellbore for the production of a desired fluid, such as petroleum. Appropriate tubing extends downwardly from the packer to a gravel pack through which the production fluid flows. Typically, an inlet covered by sand screens permits the flow of production fluid into the tubing while preventing the inflow of sand and other undesirable particulate matter.
The production fluid flows upwardly through the tubing and packer into the production tubing which conducts the production fluid to a surface location or other collection point. The production tubing may have substantial length and is subject to expansion and contraction while in the wellbore. Thus, it is desirable to have a coupling between the packer and the production tubing that accommodates this movement. Often, a polished bore receptacle is latched into an upper end of the packer, and the production tubing is stung into the polished bore receptacle with an appropriate seal stack to prevent leakage between the interior of the PBR and the production tubing. A standard seal stack includes a plurality of annular spaced seals that fit within the interior of the PBR.
Conventionally, downhole deployment of the PBR and the production tubing with associated seal stack required two trips downhole. The polished bore receptacle was initially deployed downhole and latched to the packer. The seal stack and production tubing were then deployed downhole and coupled to the polished bore receptacle in a second operation, i.e. trip downhole. The need for a second trip downhole added substantial time and expense to the overall deployment operation.
Attempts have been made to deploy the PBR and seal stack in a single trip by precoupling the seal stack within the PBR. The assembled unit can then be moved downhole and latched to the packer. However, because air is trapped between the seals of the seal stack at a relatively low surface pressure, e.g. atmospheric pressure, a substantial pressure differential results once the PBR and seal stack are moved to the downhole, high pressure environment. The comparatively high external pressure tends to squeeze the PBR, thereby reducing the internal diameter of the PBR and restricting motion of the seal stack within the PBR.
It would be advantageous to have a system and method that permitted the deployment of a polished bore receptacle, seal stack and production tubing in a single trip downhole while allowing for pressure equalization between the seals of the seal stack.
SUMMARY OF THE INVENTION
The present invention features a latch for connecting a deployment tubing, having a seal stack, to a polished bore receptacle such that the deployment tubing and the polished bore receptacle may be deployed downhole simultaneously. The latch includes an outer latch housing having an interior passage of sufficient size to permit passage of a seal stack therethrough. The outer latch housing also includes a PBR connector end designed to engage the polished bore receptacle. The latch further includes an inner latch housing having a tubing connector end designed to engage the deployment tubing. Additionally, a housing coupler is connected between the outer latch housing and the inner latch housing. The housing coupler may be selectively disconnected to permit passage of the inner latch housing and the seal stack through the interior passage.
According to another aspect of the present invention, a system and method are provided for deploying a polished bore receptacle at a packer located downhole in a wellbore. The system includes a deployment tubing and a seal disposed about the deployment tubing. The system further includes a polished bore receptacle and a releasable latch. The releasable latch is coupled to the deployment tubing and to the polished bore receptacle. The design of the releasable latch permits the seal to be held outside of the polished bore receptacle during deployment. However, upon attachment of the polished bore receptacle to the packer, the releasable latch may be activated to permit insertion of the seal into the polished bore receptacle.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and:
FIG. 1
is a front elevational view of a system positioned in a wellbore, according to a preferred embodiment of the present invention;
FIG. 2
is a front elevational view of the system of
FIG. 1
during movement of the polished bore receptacle downhole for latching to the packer;
FIG. 3
is a front elevational view of the system of
FIG. 1
in which the polished bore receptacle is latched to the packer;
FIG. 4
is a front elevational view of the system of the system of
FIG. 3
in which the seal stack and production tubing have been unlatched from the polished bore receptacle;
FIG. 5
is a front elevational view of the system illustrated in
FIG. 1
in which the seal stack has been inserted into the polished bore receptacle; and
FIG. 6
is a partial cross-sectional view of the “one-trip” seal latch that permits deployment of the polished bore receptacle, seal stack and tubing in a single trip downhole, according to a preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention permits the deployment of a polished bore receptacle, tubing and seal stack with a single trip into a wellbore. To accomplish the single trip deployment, the tubing, e.g. production tubing, and seal stack are connected to the polished bore receptacle by a seal latch, as described below. Use of the seal latch is described herein in combination with a typical production system to facilitate explanation of the use and function of the seal latch system, but this description should not be construed as limiting. The seal latch system can be used in a variety of environments and applications.
Referring generally to
FIG. 1
, an exemplary application of a production system
10
is illustrated. Typically, a wellbore
11
is formed in a production formation
12
and lined with a wellbore casing
14
. Within wellbore casing
14
, a packer
16
, such as a Quantum Gravel Pack Packer, is deployed at a desired location within wellbore
11
. A packer extension
18
extends downwardly from packer
16
and may cooperate with a circulating housing
20
having a port closure sleeve, as known to those of ordinary skill in the art.
Production fluids, such as petroleum, enter wellbore casing
14
through perforations in casing
14
and often flow through a production screen
22
. Production screen
22
tends to prevent sediment and particulate matter from settling into system
10
, while allowing the inflow of production fluid. As the production fluid flows through production screen
22
it moves upwardly through packer extension
18
and packer
16
so that it may ultimately be produced through a tubing
24
, e.g. production tubing, to a storage location at, for example, the earth's surface.
The system also may include a bull plug
26
generally disposed below production screen
22
. A gravel pack
28
also is disposed around production screen
22
proximate bull plug
26
. Gravel pack
28
includes aggregate used to fill a region surrounding production screen
22
.
System
10
further includes a polished bore receptacle
30
coupled to packer
16
by a latch
32
, such as an anchor latch. Also, polished bore receptacle
30
is connected to tubing
24
and a seal stack
34
by a one-trip seal latch
36
.
Seal stack
34
includes a plurality of seals
38
, e.g. five sets of seals
38
that are spaced along tubing
24
, but designed for insertion into a polished internal bore
40
of polished bore receptacle
30
. Typically, seals
38
are annular seals disposed about tubing
24
that sometimes have a chevron shape. Furthermore, a snap latch
42
is disposed about tubing
24
at a location above seal stack
34
to provide an indication of proper insertion of seal stack
34
into polished bore receptacle
30
.
Polished bore receptacle
30
is used in combination with seal stack
34
to accommodate expansion and contraction of tubing
24
, as well as other linear movements of tubing
24
, without disturbing the operation of system
10
. Thus, prior to production of fluids through system
10
, seal stack
34
is moved from the position illustrated in
FIG. 1
to a position within the polished internal bore
40
of polished bore receptacle
30
. The desired position within polished bore receptacle
30
allows for both downward and upward movement of the seal stack.
Insertion of seal stack
34
into polished bore receptacle
30
prior to deployment within wellbore
11
leads to detrimental pressure differentials acting on the polished bore receptacle. Therefore, seal latch
36
is designed to permit simultaneous deployment of polished bore receptacle
30
, seal stack
34
and tubing
24
while avoiding insertion of seal stack
34
into polished bore receptacle
30
until the system
10
is fully deployed within wellbore
11
.
Referring generally to
FIGS. 2 through 5
, the installation of polished bore receptacle
30
, seal stack
34
and tubing
24
in a single, downhole trip is illustrated. It should be noted that each of
FIGS. 2
,
3
and
4
is illustrated in three sections, e.g.
2
A,
2
B and
2
C, because of the length of system
10
. Each section of a given Figure continues into the subsequent section as indicated by the dashed lines.
In
FIG. 2
, tubing
24
and seal stack
34
are connected to polished bore receptacle
30
by seal latch
36
. This entire assembly is moved downhole towards packer
16
until latch
32
is in proximity to packer
16
. Preferably, latch
32
is an anchor latch having one or more seals
44
and a latching mechanism
46
designed for engagement with an upper receptacle
48
of packer
16
. The downward movement is continued until latch
32
securely engages receptacle
48
of packer
16
, as illustrated in FIG.
3
.
After securing polished bore receptacle
30
to packer
16
, tubing
24
, and seal stack
34
are lifted with sufficient tensile force to release seal latch
36
, as illustrated in FIG.
4
. The lifting of tubing
24
is accomplished by conventional deployment equipment located, for example, at the surface of the earth. Because polished bore receptacle
30
has been securely latched to packer
16
, the tensile force does not lift the polished bore receptacle but rather releases seal latch
36
such that seal stack
34
may be drawn upwardly. Typically, a guide shoe
50
, e.g. mule shoe, is attached below seal stack
34
to guide seal stack
34
back into polished bore receptacle
30
if pulled free during the lifting motion. For some applications, it may be desirable to lift seal stack
34
and guide shoe
50
above an upper end
52
of polished bore receptacle
30
to ensure release of seal latch
36
.
Subsequent to release of seal latch
36
, tubing
24
and seal stack
34
are moved downwardly into the interior
40
of polished bore receptacle
30
, as illustrated in FIG.
5
. Preferably, seal stack
34
is inserted into polished bore receptacle
30
until snap latch
42
engages upper end
52
of polished bore receptacle
30
. Typically, the snap latch
42
is designed to release upon application of a specific tensile force. Release of snap latch
42
from upper end
52
under the specific tensile force demonstrates successful deployment of seal stack
34
into polished bore receptacle
30
. After connecting snap latch
42
with upper end
52
(one or more times) to ensure that seal stack
34
is appropriately positioned within the interior of polished bore receptacle
30
, snap latch
42
is lifted from and maintained above upper end
52
. Once properly positioned, system
10
may be operated for the production of fluid.
An exemplary embodiment of seal latch
36
that permits the one-trip deployment of a polished bore receptacle, seal stack and tubing is illustrated in FIG.
6
. Seal latch
36
generally includes an outer housing
54
and an inner housing
56
. Outer housing
54
and inner housing
56
are connected by a releasable housing coupler
58
.
Inner housing
56
includes a tubing connector end
60
designed for connection to tubing
24
at a location beneath seal stack
34
. For example, tubing connector end
60
may include an internally threaded region
62
that may be threadably engaged with a corresponding externally threaded region at the lower connecting end of tubing
24
.
Generally opposite tubing connector end
60
, inner housing
56
includes an attachment end
64
designed for attachment to the mule shoe
50
. Attachment end
64
may include, for example, an external threaded region
66
designed for threaded engagement with corresponding internal threads on mule shoe
50
.
Inner housing
56
further includes an exterior surface
68
sized to fit within a hollow interior
70
formed by an interior surface
72
of outer housing
54
. Exterior surface
68
may include a pair of annular recessed areas
74
for receiving debris barriers
76
. Debris barriers
76
are designed to prevent the flow of particulates and other debris between outer housing
54
and inner housing
56
, and may be formed as a rubber on metal bonded seal. However, typically it is not necessary for the debris barriers to form a fluid-tight seal. Debris barriers
76
preferably also act to centralize inner housing
56
within outer housing
54
.
In the illustrated embodiment, inner housing
56
is formed by the combination of an upper section
78
and a lower section
80
. Upper section
78
and lower section
80
are joined at a connection region
82
by, for example, threaded engagement. In the embodiment shown, upper section
78
includes external connector threads
84
designed for threaded engagement with internal connector threads
86
of lower section
80
. It should be noted that inner housing
56
may be formed of a single section or multiple sections joined in a variety of ways.
Outer housing
54
includes a PBR connector end
88
designed to engage polished bore receptacle
30
. One exemplary method of joining PBR connector end
88
and polished bore receptacle
30
is by threaded engagement. For example, PBR connector end
88
may have an internally threaded region
90
designed to threadably receive corresponding external threads formed on the upper end of polished bore receptacle
30
. PBR connector end
88
also may include a plurality of threaded radial openings
92
for receiving set screws that are tightened against the exterior surface of polished bore receptacle
30
. Additionally, PBR connector end
88
is designed to orient polished bore receptacle
30
such that inner housing
56
and seal stack
34
may freely pass through interior passage
70
and into the interior
40
of polished bore receptacle
30
.
At an end opposite PBR connector end
88
, outer housing
54
includes an optional connector
94
. Connector
94
typically is designed for use in latching other devices or to permit attachment of a fishing tool.
In the exemplary embodiment illustrated, outer housing
54
is formed by joining three sections, an upper section
96
, a middle section
98
and a lower section
100
. However, outer housing potentially may be formed by a single housing or by multiple housings joined according to a variety of methods. In the exemplary embodiment, the three sections
96
,
98
,
100
are joined at a pair of threaded regions
102
.
Housing coupler
58
secures outer housing
54
to inner housing
56
during deployment of polished bore receptacle
30
, seal stack
34
and tubing
24
. However, upon latching of polished bore receptacle
30
to packer
16
, housing coupler
58
permits the selective decoupling or disconnection of inner housing
56
from outer housing
54
such that inner housing
56
and seal stack
34
may be inserted into polished bore receptacle
30
. Potentially, a variety of housing coupler designs may be utilized, but a preferred, exemplary design has been illustrated.
In the illustrated embodiment, housing coupler
58
includes a coupling member
104
, such as a collet. Coupling member
104
is an annular member having an exterior surface
106
designed to fit within the interior surface
72
of outer housing
54
. Coupling member
104
also includes an interior surface
108
sized to fit about the exterior of inner housing
56
. Furthermore, coupling member
104
includes a base portion
110
having an external recess, such as an annular groove
112
. At least one and preferably a plurality of fingers
114
, e.g. eight fingers, extend generally axially from base portion
110
. Each finger
114
includes an expanded head
116
having a hook portion
118
extending radially outwardly and a retention portion
120
extending radially inward.
While outer housing
54
is joined to inner housing
56
, retention portion
120
is held within a retention recess, e.g. a groove
122
, formed in the external surface
68
of inner housing
56
. The abutment of a radially exterior surface of hook portion
118
against interior surface
72
of outer housing
54
secures retention portion
120
within groove
122
. Simultaneously, one or more shear screws
124
are threadably engaged with corresponding radial openings
126
formed through outer housing
54
. The shear screws
124
are threaded into engagement with the annular groove
112
formed in base portion
110
of coupling member
104
. The shear screws
124
cooperate with retention portion
120
to prevent linear movement of inner housing
56
with respect to outer housing
54
during deployment of polished bore receptacle
30
and seal stack
34
to packer
16
.
Due to some compressive forces exerted during latching of polished bore receptacle
30
to packer
16
, it may be desirable to protect fingers
114
against such forces. In the illustrated embodiment, lower section
100
of outer housing
54
includes a slender support member
128
that extends between interior surface
108
of coupling member
104
and exterior surface
68
of inner housing
56
into abutting engagement with retention portions
120
of fingers
114
. The support member
128
absorbs compressive forces that could otherwise be applied against fingers
114
.
Following successful latching of polished bore receptacle
30
to packer
16
, a sufficient tensile force is applied to tubing
24
and inner housing
56
to break or shear the shear screws
124
. Specifically, a lower abutment surface
130
, e.g. the lower wall forming retention groove
122
, engages retention portion
120
and lifts coupling member
104
until shear screws
124
are sheared. As coupling member
104
is lifted, hook portion
118
moves past a hook retainer
132
formed in interior surface
72
of outer housing
54
. Fingers
114
spring radially outward such that hook portion
118
engages hook retainer
132
when inner housing
56
and seal stack
34
are inserted into polished bore receptacle
30
. To ensure that fingers
114
flex outwardly, upper section
96
of outer housing
54
includes a sloped abutment
134
designed to engage retention portion
120
and force fingers
114
in a radially outward direction. With inner housing
56
separated from outer housing
54
and coupling member
104
retained by hook retainer
132
, inner housing
56
and seal stack
34
may be inserted into polished bore receptacle without interference.
It will be understood that the foregoing description is of preferred exemplary embodiments of this invention, and that the invention is not limited to the specific forms shown. For example, the present system may be utilized in a variety of environments and applications; the design of the one trip seal latch housings and coupling member may be altered to accommodate the specific environment or application; and the methods of attaching the seal latch to both the tubing, e.g. production tubing, and the polished bore receptacle may be changed. These and other modifications may be made in the design and arrangement of the elements without departing from the scope of the invention as expressed in the appended claims.
Claims
- 1. A latch for connecting a deployment tubing, having a seal stack, to a polished bore receptacle such that the deployment tubing and the polished bore receptacle may be deployed downhole simultaneously, comprising:an outer latch housing having: an interior passage of sufficient size to permit passage of the seal stack therethrough; and a PBR connector end designed to engage the polished bore receptacle; an inner latch housing having a tubing connector end designed to engage the deployment tubing; and a housing coupler connected between the outer latch housing and the inner latch housing, wherein the housing coupler may be selectively disconnected to permit passage of the inner latch housing and the seal stack through the interior passage.
- 2. The latch as recited in claim 1, wherein the housing coupler comprises a coupling member and a shear screw.
- 3. The latch as recited in claim 2, wherein the coupling member includes: a base having a recessed region to receive the shear screw; and a flexible finger having an enlarged retention end.
- 4. The latch as recited in claim 3, wherein the inner latch housing includes a recess sized to receive the enlarged retention end.
- 5. The latch as recited in claim 4, wherein the enlarged retention end is held in the recess by an interior surface of the outer latch housing until the housing coupler is selectively disconnected.
- 6. The latch as recited in claim 5, wherein the outer latch housing includes a radial opening sized to receive the shear screw therethrough for insertion into the recessed region of the base of the coupling member.
- 7. The latch as recited in claim 6, wherein the flexible finger is biased radially outwardly towards the interior surface.
- 8. The latch as recited in claim 7, wherein the interior surface includes a relief area that permits the flexible finger to move out of the recess when the inner latch housing is moved a sufficient longitudinal distance with respect to the outer latch housing.
- 9. The latch as recited in claim 8, wherein the outer latch housing includes a catch to retain the flexible finger in the relief area.
- 10. The latch as recited in claim 9, wherein the-outer latch housing includes a sloped abutment positioned to force the flexible finger in a radially outward direction when the inner latch housing is moved a sufficient longitudinal distance with respect to the outer latch housing.
- 11. The latch as recited in claim 9, further comprising a debris barrier disposed between the inner latch housing and the outer latch housing.
- 12. The latch as recited in claim 2, wherein the coupling member comprises a base and a plurality of flexible fingers.
- 13. A system for deploying a polished bore receptacle downhole in a wellbore, comprising:a deployment tubing; a seal disposed about the deployment tubing; a polished bore receptacle; and a releasable latch coupled to the deployment tubing and to the polished bore receptacle to maintain the seal external of the polished bore receptacle during deployment, wherein upon attachment of the polished bore receptacle to the packer, the releasable latch may be released to permit insertion of the seal into the polished bore receptacle.
- 14. The system as recited in claim 13, wherein the deployment tubing comprises production tubing.
- 15. The system as recited in claim 13, wherein the seal comprises a seal stack having a plurality of spaced, annular seals disposed about the deployment tubing.
- 16. The system as recited in claim 15, wherein the releasable latch comprises an outer housing, an inner housing and at least one shear screw to hold the outer housing in a desired position relative to the inner housing prior to insertion of the seal stack into the polished bore receptacle.
- 17. The system as recited in claim 16, wherein the releasable latch further comprises a retainer, the retainer including: a base having a recessed region to receive the shear screw; and a flexible finger having an enlarged retention end.
- 18. The system as recited in claim 17, wherein the inner housing includes a recess sized to receive the enlarged retention end.
- 19. The system as recited in claim 18, wherein the enlarged retention end is held in the recess by an interior surface of the outer housing until the housing coupler is selectively disconnected.
- 20. The system as recited in claim 19, wherein the interior surface includes a relief area that permits the flexible finger to move out of the recess when the inner latch housing is moved a sufficient longitudinal distance with respect to the outer latch housing.
- 21. A method for deploying a tubing string and a polished bore receptacle with a single trip into a wellbore, comprising:deploying a tubing, a seal stack and a polished bore receptacle simultaneously into the wellbore; maintaining the seal stack at a position external to the polished bore receptacle; and inserting the seal stack into the polished bore receptacle after the polished bore receptacle is moved to a desired downhole location.
- 22. The method as recited in claim 21, further comprising latching the polished bore receptacle to a packer located at the desired downhole location.
- 23. The method as recited in claim 22, further comprising connecting the tubing to the polished bore receptacle by a releasable latch.
- 24. The method as recited in claim 23, further comprising releasing the releasable latch by applying a tensile force to the tubing after latching the polished bore receptacle to the packer.
- 25. The method as recited in claim 24, wherein releasing includes shearing a shear screw upon application of the tensile force.
US Referenced Citations (12)