Information
-
Patent Grant
-
6328112
-
Patent Number
6,328,112
-
Date Filed
Monday, February 1, 199925 years ago
-
Date Issued
Tuesday, December 11, 200122 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 166 386
- 166 373
- 166 3326
- 166 3321
- 166 667
- 166 666
- 251 193
- 251 194
- 251 195
- 251 319
- 137 62526
-
International Classifications
-
Abstract
A valve assembly includes a seat having at least an opening and a first surface. A cover has a contact surface that is slideably and sealingly engaged to the first surface of the seat to form a seal when the contact surface completely covers the at least one opening.
Description
BACKGROUND
The invention relates to valves used to control fluid flow in wells.
In a wellbore, one or more valves may be used to control flow of fluid between different sections of the wellbore. These different sections may include multiple completion zones in vertical or deviated wells or in multilateral wells. Various types of valves are available, including ball valves, sleeve valves, flapper valves and other types of valves.
Conventional sleeve valves are mechanically actuated with a tool lowered into production tubing at the end of a slickline or coiled tubing, for example. To actuate the sleeve valve between open and closed positions, the slickline or coiled tubing is raised or lowered at the well surface. Referring to
FIG. 1A
, portions of a sleeve valve
30
and production tubing
32
are illustrated. The sleeve valve
30
includes a longitudinally moveable concentric sleeve having a port
38
that when aligned with a corresponding port
34
in the production tubing
32
allows fluid flow between the bore
33
and the exterior of the production tubing
32
. As illustrated, when the sleeve valve
30
is in the closed position, the body of the concentric sleeve and O-ring seals
36
and
37
block fluid flow through the production tubing port
33
. The seals
36
and
37
typically are made of an elastomer material.
Intervention required to operate such mechanically actuated sleeve valves makes them relatively expensive and time-consuming to operate. Because of the depths of some reservoirs, a long slickline may be needed to run an actuation tool downhole. Further, in horizontal or highly deviated wells, the process of moving the sleeve may be very expensive because of the need for coiled tubing or other more complicated actuating mechanisms to carry the tool to the sliding sleeve. Such problems are exacerbated in a well that uses subsea technology, with no platform over the well, in which case an intervention vessel may be needed to access the sea floor to run a tool downhole to actuate the sleeve valve. Further, after a sleeve valve has been exposed to a wellbore environment for some time, the sleeve may be stuck or rendered more difficult to operate due to corrosion and debris. If the sleeve is stuck, then a mechanical jarring device may have to be run into the production tubing to jar the sleeve loose.
In addition, the hydraulic seals formed of an elastomer material may add additional drag to movement of the sleeve valve, rendering its operation even more difficult. Further, due to the presence of the elastomer seals, reliability may be an issue if the sleeve valve is left downhole for a long period of time due to exposure to caustic fluids.
More recently, remotely actuatable sleeve valve systems have been developed. Referring to
FIG. 1B
, a remotely actuatable sleeve valve system positioned downstream from a packer
20
is illustrated. As illustrated, the sleeve valve system is positioned adjacent a reservoir
12
in a section of a wellbore. A production tubing
10
may be extended to the reservoir
12
, which may contain oil or gas, to receive fluid from the reservoir
12
for production to the surface. A sliding sleeve valve
14
, longitudinally moveable between open or closed positions, may be mounted either outside the production tubing
10
as shown in
FIG. 1B
or inside the production tubing as in FIG.
1
A. In the open position, ports
15
of the sleeve valve
14
are aligned to corresponding ports in the production tubing
10
.
To operate the sleeve valve
14
, it may be coupled to an actuator
16
controlled by an actuator drive system
18
, which typically may be a linear actuator. Rotary actuators may also be used. In addition, the actuator
16
may be controlled hydraulically or electrically. In response to remotely transmitted electrical signals or hydraulic actuation, the actuator drive system
18
causes longitudinal movement of the actuator
16
.
Sleeve valves may require relatively large forces to overcome the drag from hydraulic seals in the valve, particularly when the sleeve valve is exposed to high pressure. In addition, a sleeve valve may require a relatively long stroke to move between a fully open position and a fully closed position. As a result of the relatively large forces and long strokes employed to actuate a sleeve valve, an actuator (such as the actuator system
18
in
FIG. 1B
) employed to actuate the sleeve valve may need to be relatively high powered. To provide such high power, sophisticated electronic circuitry may need to be employed and relatively large diameter electrical cables may need to be run from the surface to the valve actuator mechanism.
Thus, a need arises for an improved valve system for downhole use in wells.
SUMMARY
In general, according to one embodiment, a valve assembly includes a seat having at least an opening and a first surface. A cover has a contact surface that is slideably and sealingly engaged to the first surface of the seat to form a seal when the contact surface completely covers the at least one opening.
Other features will become apparent from the following description and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A and 1B
illustrate prior art sleeve valve systems used in a well.
FIGS.
2
and
3
A-
3
B are diagrams of a valve mechanism according to an embodiment of the invention.
FIGS. 4A-4C
are cross-sectional views of a valve system according to an embodiment.
FIG. 5
is a diagram of portions of the valve system of
FIGS. 4A-4C
mounted on a portion of a production tubing.
FIG. 6
is a cross-sectional diagram of a portion of the valve system of
FIGS. 4A-4C
.
FIG. 7
is a diagram of a valve system according to another embodiment of the invention.
FIG. 8
is a cross-sectional view of a valve mechanism in a closed or partially closed position in the valve system of FIG.
7
.
FIG. 9
is a diagram of a completion system positioned in a wellbore capable of employing valve systems according to some embodiments.
FIGS. 10A-10B
,
11
, and
12
A-
12
C illustrate further embodiments of valve mechanisms.
FIG. 13
illustrates a cover member used in the valve mechanism of FIGS.
2
and
3
A-
3
B having a tapered lower edge.
DETAILED DESCRIPTION
In the following description, numerous details are set forth to provide an understanding of the present invention. However, it is to be understood by those skilled in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.
Referring to
FIG. 2
, an exploded view of a valve mechanism
100
according to an embodiment of the invention is shown. Basically, the valve mechanism
100
includes a seat (or other support member)
114
having a fluid flow opening or orifice
102
over which an outer disk (or other cover member)
104
and an inner disk (or other cover member)
106
are slideable to form a variable orifice to control fluid flow through the opening
102
. The seat
114
is attached to a frame
112
, which in one embodiment may be mounted to the housing of a production tubing. In this embodiment, the opening
102
in the seat
114
is aligned with a corresponding opening in the production tubing so that fluid may flow from outside the tubing to the bore of the tubing, and vice versa. In another embodiment, the frame
112
of the valve mechanism
100
may be part of the housing of the production tubing. One feature of the cover member (e.g., disk
104
or
106
) according to some embodiments is that it has a width that extends less than the full circumference of the tubing, which is unlike a conventional sliding sleeve in a sleeve valve.
Although reference is made to use of the valve mechanisms with a production tubing, it is to be understood that the invention is not to be limited in this respect. Valve mechanisms according to further embodiments may be used for fluid flow control in other types of tubing, pipes, and various downhole tools and barriers including through-tubing flow. Thus, the term tubing as used in this description has a general meaning and includes pipes, annuluses, mandrels, and the like. In addition, although the illustrated disks
104
and
106
generally have a circular shape, it is contemplated that the disks may have other shapes in other embodiments, including rectangular, square, oval, and so forth. The same may be true also of the opening or orifice
102
.
The disks
104
and
106
are adapted to slideably and sealingly engage corresponding surfaces of the seat
114
. If the disks
104
and
106
of the valve mechanism
100
fully cover the opening
102
, the valve is closed. By sliding the outer and inner disks
104
and
106
over the opening
102
formed in the valve seat
114
, the flow area (and hence the flow rate) through the opening may be varied. When the outer disk
104
completely covers the opening
102
in the valve seat
114
, flow of fluid is blocked by a face-to-face seal between the bottom face of the disk
104
and the upper face of the seat
114
. In effect, the contact or engagement between the bottom face (contact surface) of the disk
104
and the upper face of the seat
114
forms a periphery around which a seal is formed. This seal is enhanced by pressure applied by external well fluids on the top surface of the outer disk
104
. Similarly, the inner disk
106
and the seat
114
form a fluid seal when the inner disk
104
completely covers the opening
102
from the other side.
In one embodiment, the disks
104
and
106
(or other cover members) are moved by an actuator to open and closed positions. In other embodiments, the seat
114
may be moved instead of the disks
104
and
106
.
The outer disk
104
sits in a slot
116
of a disk carrier
118
, and the inner disk
106
sits in a slot
120
of a disk carrier
122
. Each of the slots
116
and
120
has an enlarged portion to receive a corresponding one of the disks
104
and
106
. The open portions of the slots
116
and
120
line up with the opening
102
to allow fluid flow when the valve is fully or partially open.
A spring washer
124
(which may be in one embodiment a Belleville washer) is placed around a receiving portion of the outer disk
104
to apply a small pre-load force to prevent the outer disk from floating away from the seat
114
. Similarly, a spring washer
126
is placed around a receiving portion of the disk
106
.
Referring to
FIGS. 3A and 3B
, the valve mechanism
100
is shown in its fully closed and fully open positions, respectively. According to one embodiment, both the inner and outer disk carriers
118
and
122
are moved together by an actuator mechanism. However, in a different embodiment, the outer and inner disk carriers
118
and
122
may be actuated independently. As shown, the disk carriers
118
and
122
holding the disks
104
and
106
are moved longitudinally relative to the frame
112
holding the valve seat
114
.
By using two disks
104
and
106
, one on each side of the valve seat
114
, pressure integrity may be maintained in the presence of pressure from either direction, e.g., from outside the production tubing or from inside the production tubing. If only one disk were used, for example, if the inner disk
106
were removed, high pressure from inside the production tubing may push the outer disk
104
away from the seat
114
, which may reduce the integrity of the seal between the disk
106
and the seat
114
. This may result in a leak through the opening
102
. Using both the outer and inner disks
104
and
106
as illustrated, a bi-directional valve is provided to seal fluid pressure from either outside the production tubing or inside the tubing.
However, in another embodiment that includes a disk only on one side of the seat
114
, a mechanism (such as a pre-load spring) may be coupled to apply sufficient pre-load pressure against the disk so that the disk can maintain a seal even in the presence of pressure that tends to push the disk away from the seat. In addition, although the valve mechanism
100
is described in conjunction with a production tubing, it is to be understood that the valve mechanism according to embodiments of the invention may suitably be used in other systems.
To facilitate the movement of the disks
104
,
106
over corresponding surfaces of the valve seat
114
, the disks
104
,
106
and the seat
114
may be formed of or coated with a material having a low coefficient of friction. Such a material may include polycrystalline-coated diamond (PCD), which may in one configuration have a coefficient of friction ranging from about 0.08 to about 0.15. Other materials that may be used include vapor deposition diamonds, ceramics, silicon nitride, hardened steel, carbides, cobalt-based alloys, or other low friction materials having suitable erosion resistance. The coefficient of friction for carbides and ceramics may range from about 0.11 to 0.2. Other materials having lesser or greater coefficients of friction may also be used.
Other characteristics of materials used to form the disks
104
,
106
(or other types of cover members) and the seat
114
(or other type of support member) are that the materials are erosion resistant and have suitable hardness. For example, polycrystalline-coated diamond has a hardness that may range from about 5,000 to 8,000 kg/mm
2
(knoops). Certain compositions of carbide and types of ceramic may have a hardness ranging between about 1,300 to 3,200 knoops. With less severe conditions, cobalt-based alloys such as satellite or Cr—B—S—Ni alloys such as colmonoy having a hardness above about 400 knoops may be used. Materials having other hardnesses may also be used.
In one embodiment, the outer and inner disks
104
and
106
and the seat
114
may be formed of a tungsten carbide material that is coated with PCD. In further embodiments, the outer and inner disks
104
and
106
may be formed of other types of materials, e.g., steel, steel alloy, etc. By coating the disks
104
,
106
and the seat
114
with a material having a low coefficient of friction, the valve may be opened or closed with reduced force even in the presence of high internal or external pressure acting on the outer or inner disks. Further, the PCD and tungsten carbide materials(or any of the other materials listed above) are erosion resistant, offering significant life improvement over conventional materials in the erosive downhole environment. Corrosive materials that may be produced along with oil and gas may include carbon dioxide, salt, water, H
2
S, and so forth.
In addition, PCD coated tungsten blanks are commercially available, and therefore manufacturing the valve mechanism according to some embodiments of the invention may be relatively inexpensive. Further, another advantage of a valve system including one or more valve mechanisms according to some embodiments is that the distance traversed by the outer and inner disks
104
and
106
between fully opened and fully closed positions may be relatively small. As a result, a short stroke actuator may be utilized. For example, the stroke to actuate the valve mechanism between fully open and fully closed positions may be about 1.5 inches in one example embodiment. Combining the relatively short stroke and low coefficient of friction materials used to form the valve mechanism according to some embodiments of the invention, a relatively low power actuator may be used to open and close the valve. The power needed to actuate the valve mechanism according to some embodiments may be at least an order of magnitude less than the power needed to operate other remotely actuatable conventional sleeve valves.
Although short strokes to actuate valve mechanisms according to some embodiments may be advantageous in some applications, it is noted that in further embodiments longer strokes may be employed to actuate valve mechanisms.
In one example application, to control fluid flow between a reservoir and a production tubing, a valve system includes several of the valve mechanisms
100
illustrated in FIGS.
2
and
3
A-
3
B. Referring to
FIGS. 4A-4C
, a valve system includes two valve mechanisms
100
A and
100
B that are operable by an actuator
150
. The valve mechanisms
100
A and
100
B in the illustrated embodiment are linearly coupled to form a linear valve system in which two or more valves may be linearly actuated together.
Referring further to
FIG. 5
, the valve system including valve mechanisms
100
A,
100
B and the actuator
150
may be mounted onto the housing of a production tubing
180
. In
FIG. 5
, portions of the valve mechanisms
100
A,
100
B and actuator mechanism
150
are not shown, including the inner and outer disks and disk carriers. In the illustrated embodiment, the valve system is formed integrally with a housing portion
170
of the production tubing. In alternative embodiments, the valve system may be attached to the housing of the production tubing
180
using some type of fastener.
The production tubing housing portion
170
is made up of the individual support frames
112
A,
112
B (
FIG. 2
) in the valve mechanisms
100
A,
100
B. As shown in
FIG. 5
, seats
114
A,
114
B are attached to the housing portion
170
to receive the outer and inner disks
104
A,
104
B and
106
A,
106
B of the valve mechanisms
100
A,
100
B. As discussed, the outer and inner disks of the valve mechanisms
100
A,
100
B are moveable over the openings
102
A,
102
B to provide variable orifices to control fluid flow between the inner bore
182
and the exterior of the production tubing
180
.
The embodiment illustrated in
FIGS. 4A-4C
and
5
includes valve orifices
102
A,
102
B that are arranged longitudinally along the tubing
180
. In other embodiments, the valve orifices may be arranged in a number of different configurations, including the following example arrangements: the orifices are spaced along the circumference of the tubing; the orifices are phased with respect to each other as they travel down the tubing (e.g., a helical or other pattern); and so forth. In addition, although cover members such as disks
104
and
106
in one embodiment are adapted to cover one orifice, other types of cover members may be adapted to cover more than one orifice.
A seat
152
for the actuator mechanism
150
is also attached to the housing portion
170
. The seat
152
includes an interconnecting port
154
through which inner and outer actuator covers
160
and
158
of the actuator mechanism
150
may be coupled. The actuator covers
160
and
158
are slideable over the seat
152
in response to actuation by the actuator mechanism
150
. To provide low resistance contacts, the actuator covers
160
and
158
and seat
152
may also be coated with PCD layers in one embodiment. Corresponding surfaces of the actuator covers
160
and
158
and the seat
152
form face-to-face seals to prevent fluid from flowing into the port
154
.
As shown in
FIGS. 4A-4C
, the outer actuator cover
158
is coupled to move the outer disk carriers
118
A,
118
B (of the valve mechanisms
100
A,
100
B, respectively) longitudinally to adjust the positions of the outer disks
104
A,
104
B with respect to the openings
102
A,
102
B of the valve mechanisms
100
A,
100
B, respectively. Similarly, the inner actuator cover
160
of the actuator mechanism
150
is coupled to move the inner disk carriers
122
A,
122
B longitudinally.
In one embodiment, the disk carrier
118
A may be integrally attached to the disk carrier
118
B, which in turn may be integrally attached to a drawer member
162
that is attached to the outer actuator cover
158
. Similarly, the disk carrier
122
A may be integrally attached to the disk carrier
122
B, which in turn may be integrally attached to a drawer member
164
that is coupled to the inner actuator cover
160
. Further, the actuator covers
158
and
160
are fixedly attached to each other by a coupling member
156
that is passed through the interconnecting port
154
. Space is provided in the interconnecting port
154
to allow the actuator covers
158
and
160
to move longitudinally so that the valve system may be actuated open and closed.
In the illustrated embodiment, because the actuator covers
158
and
160
are fixed to each other by the coupling member
156
, they are actuated to move longitudinally together. In an alternative embodiment, the actuator covers
158
and
160
may be separately actuated if the coupling member
156
is removed.
FIG. 4A
illustrates the valve system in a fully open position.
FIG. 4C
illustrates the valve system in a fully closed position.
FIG. 4B
illustrates the valve system in a partially open position between the fully open and fully closed positions, such as during production of well fluids from the reservoir through the production tubing to the surface. The fluid flow rate through the valve system may be controlled by varying the position of the disks
104
A,
104
B and
106
A,
106
B over their respective fluid flow openings
102
A,
102
B. As shown, the fluid flow openings
102
A,
102
B are opened and closed together since the disk carriers for the outer and inner disks are attached to each other.
The number of fluid flow openings
102
formed in a valve system according to some embodiments of the invention depends on the total size desired for a flow port in the valve system. An advantage of some embodiments is that each valve mechanism may be made relatively small for ease of manufacture and for reduced cost. To provide a flow port of sufficient size, multiple valve mechanisms
100
may be concatenated.
In an alternative embodiment, rather than being coupled linearly in a sequence, the valve mechanisms may be arranged around the outer radius of the production tubing. Other arrangements of valve mechanisms may also be possible in further embodiments.
In some embodiments, each disk
104
or
106
may have an angled or tapered slightly protruding lower edge
107
(
FIG. 13
) that abuts the seat
114
of the valve mechanism. The tapered lower edge
107
is able to rake accumulation or debris from the seat
114
as the disk
104
or
106
is moved over the seat. This may aid in forming a more reliable seal.
Referring to
FIG. 6
, a cross-sectional diagram of the valve system of
FIGS. 4A-4C
is illustrated. The outer disk
104
includes a receiving shoulder
125
on which the spring washer
124
may sit. The spring washer
124
is retained against the shoulder
125
by the disk carrier
118
, which is held in place by a retainer bracket
214
attached to the housing body
170
of the production tubing
180
by screws
184
. As illustrated in
FIG. 6
, the frame of the valve system may be integrally attached to the housing body
170
of the production tubing
180
.
The spring washer
124
applies a force down onto the outer disk
104
to help maintain a tight seal between the outer disk
104
and the seat
114
. This is in addition to any force applied against the upper surface of the outer disk
104
by formation fluid pressure P
ext
from outside the production tubing.
The lower surface of the outer disk
104
may be coated with a layer
200
formed of a material having a low coefficient of friction (e.g., PCD). Similarly, the upper surface of the seat
114
may also be coated with a layer
202
having a low coefficient of friction.
At the inner side of the valve system, the inner disk
206
includes a receiving shoulder
127
on which the spring washer
126
may be placed. The spring washer
126
is held against the shoulder
127
by the disk carrier
122
. A sleeve
212
mounted inside the housing body
170
of the production tubing
180
holds the disk carrier
122
in place. The spring washer
126
applies a force against the lower surface of the inner disk
106
to push its upper surface against the lower surface of the seat. Further, any pressure P
int
inside the production tubing may be applied against the lower surface of the inner disk
106
. The spring washer
126
and any internal fluid pressure P
int
help maintain a relatively reliable fluid seal between the inner disk
106
and the seat
114
.
The lower surface of the seat
114
is coated with a layer
204
formed of a material having a low coefficient of friction, which is contacted to a layer
206
also formed of a material having a low coefficient of friction on the upper surface of the inner disk
106
. The layers
200
,
202
,
204
, and
206
allow for easier movement of the disks
104
,
106
relative to the seat
114
due to the reduced friction contacts.
An actuator mechanism (not shown) coupled to move the actuating mechanism
150
may be an electrical or hydraulic device, depending on the type of system used. A configuration according to one example embodiment may include a linear actuator having an acme thread or ball screw driven by a brushless direct current (DC) or stepper motor. In another embodiment, a hydraulic actuator mechanism may be controlled by fluid pressure applied down the wellbore.
Referring to
FIG. 7
, a valve system according to another embodiment is attached to a production tubing
300
. In this embodiment, four valve mechanisms
302
A,
302
B,
302
C, and
302
D are linearly coupled to an actuator mechanism
304
. In turn, the actuator mechanism
304
is controlled by a linear actuator
306
, which may be either an electrical or a hydraulic actuator.
Each valve mechanism
302
includes a cap
310
attached to a pair of moveable rods
312
,
313
. The cap
310
is attached to a disk
340
(shown in
FIG. 8
) or other suitable cover member that is adapted to cover a fluid flow opening
316
defined by a seat
314
. The pair of rods
312
,
313
are moved longitudinally by the actuator mechanism
304
to move the cap in relation to the opening
316
. In this manner, the valve mechanism
302
may be actuated between fully closed, partially open, and fully open positions. As with the embodiments described above, the disks and seats
314
of the valve mechanisms
302
may also be coated with a material having a low coefficient of friction to allow valve actuation with smaller forces.
The pair of rods
312
,
313
are passed through a series of linear bushing
320
,
321
attached by corresponding brackets
322
to the production tubing
300
housing. In the actuator mechanism
304
, a coupling member
330
fixedly attaches rods
312
,
313
. The coupling member
330
is coupled to a linear actuator
306
. By moving the pair of rods
312
,
313
longitudinally, the valve mechanisms
302
may be operated.
Referring to
FIG. 8
, a cross-section of one of the valve mechanisms
302
in a closed or partially closed position is illustrated. The seat
314
may be integrally attached to the housing of the production tubing
300
in one embodiment. The upper surface of the seat
314
may be coated with a layer
348
formed of a material having a low coefficient of resistance (e.g., PCD). The lower surface of the disk
340
may also be coated with a layer
350
formed of a material having a low coefficient of friction. The disk
340
is pushed against the seat
314
by a pre-load spring
344
, which is located in a region
346
underneath the cap
310
. The pre-load spring applies a force F
spring
against the upper surface of the disk
340
that is designed to be greater than force applied by pressure P
int
from inside the production tubing
300
. The force due to the internal pressure is P
int
*A
v
, where A
v
is the area of the lower surface of the disk
340
exposed to the opening
316
. The force F
spring
applied by the spring
344
keeps the disk
340
against the seat
314
in the presence of pressure inside the production tubing
300
.
If a valve system includes several valve mechanisms
302
according to the
FIG. 8
embodiment, the cumulative force applied by the pre-load springs
344
of the several valve mechanisms
302
may be relatively large, which may require an actuator of sufficiently high power. If the use of a high-powered actuator is undesirable, the number of valve mechanisms
302
may be reduced (to one or two, for example) so that a less expensive, lower powered actuator may be included in the valve system.
Referring to
FIGS. 10A-10B
,
11
, and
12
A-
12
C, further embodiments of valve mechanisms are illustrated. In
FIG. 10A
, a valve mechanism
500
includes a cover member
504
that is generally rectangular in shape, with a slight curve to conform to the housing
510
of a tubing or other tool. The cover member
504
is slideably and sealingly engaged to a seat
506
that is attached to or integrated with the housing
510
. As illustrated in
FIG. 10B
, an opening
502
defined by the seat
506
is shaped generally as a tear drop. Alternatively, the opening
502
may be any other number of shapes, e.g., rectangular, square, circular, oval, etc.
In
FIG. 11
, a valve mechanism
550
according to another embodiment attached or integrated with the housing
560
of a tubing or other tool
560
includes a cover member
554
that is rotatable about an axis
556
. The bottom face of the cover member
554
is slideably and sealingly engaged with a seat
558
so that the cover member
554
may be rotated to partially or completely cover an opening
552
. As illustrated, the opening
552
generally has a semi-circular shape, although other shapes are also possible.
In yet another embodiment, as illustrated in
FIGS. 12A-12C
, a valve mechanism
600
may have a cover member
610
that is rotatable about an axis
614
and a support member
612
that is attached to or integrated with the housing
602
of a tubing or other tool. Each member
610
or
612
includes an opening
604
or
606
, respectively. The cover member
610
is rotatable so that the openings
604
and
606
can line up partially or completely to provide a partially or completely open valve.
In a further alternative embodiment, multiple valve mechanisms in a valve system may be actuated sequentially, with one or more actuated open or closed before others. For example, one valve system may have a first valve mechanism with a smaller orifice than the remaining valve mechanisms. To actuate the valve system to an open position, the first valve mechanism may be actuated to an open position first followed by the rest of the valve mechanisms. This allows pressure inside the tubing or tool to equalize with pressure outside the tubing or tool, thereby making actuation of the remaining valve mechanisms easier as the amount of force applied by the difference in pressure is reduced. To actuate the valve mechanisms at different times, separate actuators may be used. Alternatively, one actuator may be used with some type of lost motion mechanism so that some valve mechanisms may be actuated before others.
Referring to
FIG. 9
, a wellbore
420
includes various example completion equipment, including casing
400
lining a vertical portion and production tubing
402
extending from the well surface to reservoirs located downhole. The wellbore
420
may be a land well or a subsea well (i.e., located under the bottom surface of the sea) with or without a production platform above the well. As examples, the completion equipment in the wellbore
420
may include an intelligent completion system (ICS), a permanent monitoring system (PMS), or other type system. An ICS may include various sensors, monitoring and measurement devices, and control units positioned downhole to monitor conditions downhole and to take actions in response to those monitored conditions, either automatically or by a command issued at the surface or remotely. A PMS includes various monitoring and measurement devices that communicate downhole conditions to systems located at the surface or remotely.
In the illustrated wellbore
420
, several production zones may be located in the vertical and deviated portions of the wellbore, including zones defined between successive packers
460
and
462
, packers
404
and
406
, and packers
408
and
410
. Perforations
428
,
430
, and
432
may be created in the three illustrated production zones to allow formation fluid to flow from reservoirs
448
,
450
, and
452
into the production tubing
402
and up to the surface. In the different production zones, valve systems
464
,
412
, and
416
according to some embodiments may be included to control fluid flow. Thus, for example, in the vertical portion of the wellbore
420
, the valve system
464
controls fluid flow into the production tubing
402
from the reservoir
448
through perforations
428
. In the deviated portion of the wellbore
420
, the valve system
412
controls fluid flow into the production tubing
402
from a reservoir
450
through the perforations
430
, and the valve system
416
controls fluid flow into the production tubing
402
from a reservoir
452
through perforations
432
.
Production from the reservoirs may occur over long time periods (e.g., months or years). Flow of fluid from the reservoirs into the production tubing depends on formation pressure applied by pressure fronts in each reservoir. Such pressure fronts may be created by a layer of water behind the reservoir, such as the water layer
449
behind the reservoir
448
. The pressure front may be relatively uniform initially when the reservoir
448
is relatively full. However, once a reservoir becomes depleted, such formation pressure fronts may become skewed, with formation pressure at one side of the reservoir greater than formation pressure at the other side. For example, in the reservoir
448
adjacent the production zone in the vertical portion of the wellbore
420
, once the formation pressure front becomes non-uniform, pressure P
1
applied at the upper side of the reservoir may be much smaller than pressure P
2
applied at the lower side. This may cause water from the water layer
449
, for example, to be produced at the lower side of the reservoir into the production zone.
To counteract this phenomenon, several valve systems according to embodiments of the invention may be placed in the production zone adjacent reservoir
448
. As the formation pressure characteristics in the reservoir
448
change, the valve systems may be remotely adjusted to vary their flow rates. For example, the flow rates of the valve systems at the lower side of the production zone may be set lower than flow rates of valve systems at the upper side because of differences in formation pressure. In fact, the lower valve systems in the production zone may be completely shut off.
According to some embodiments, each of the valve systems may be electrically actuatable in response to commands issued by an operator at the well surface or at a remote site. Sensors may be placed in each of the production zones to detect flow characteristics. The sensed information may be communicated to the surface or to a remote site. Using the communicated information, an operator may adjust the valve systems as necessary.
In another example application, the reservoirs
448
and
450
may be produced simultaneously through the production tubing
402
. However, typically, different reservoirs may be associated with different formation pressures. Such differences in formation pressures may be significant. To prevent fluid from one zone being forced into another zone due to such differences in formation pressures, valve systems according to embodiments may be adjusted to equalize flow rates such that effective production of formation fluids may be provided to the surface. Again, the valve systems in one embodiment may be adjustable remotely to properly control fluid production.
In addition, in the deviated portion of the wellbore
420
, a water table
452
may sit beneath the reservoir
450
. Pressure in the reservoir
450
may be applied by the water table
452
upwards to the production tubing
402
. However, the applied pressure front may also become non-uniform. For example, pressure P
3
applied at one end may become greater than pressure P
4
applied at the other end. If the pressure differential becomes great enough, water from the water table
452
may be produced into the production zone defined between packers
404
and
406
. To prevent this, the valve systems
412
and
416
in the two zones may be controlled such that fluid production into the zones is equalized.
Valve systems according to embodiments may have numerous applications. For example, in addition to regulating flow of hydrocarbons into the production tubing as described above, the valve systems may also be used to regulate flow of fluids from inside the pipe to the outside for applications such as gas injection regulation, water injection regulation, or other non-oil field applications. Further, the valve systems may be used for such applications as drilling drain holes from a parent well into one or more given reservoirs.
While the invention has been disclosed with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of the invention.
Claims
- 1. A valve for controlling fluid flow through at least one orifice in a wall of a downhole tubing that has a circumference, comprising:a seat defined about the at least one orifice; at least one cover selectively positionable at and between an open position and a closed position, the at least one cover slideably and sealingly engaging the seat, the at least one cover extending less than the full circumference of the tubing, wherein: the wall of the tubing has an interior and an exterior surface; the seat comprises an inner seat portion defined by the interior surface about the at least one orifice and an outer seat portion defined by the exterior surface about the at least one orifice; a first cover selectively positionable at and between an open and closed position, the first cover slideably and sealingly engaging the inner seat portion; and a second cover selectively positionable at and between an open and closed position, the second cover slideably and sealingly engaging the outer seat portion.
- 2. A downhole valve assembly for controlling fluid flow through an orifice defined in a side of a tubing, comprising:a seat member comprising a first surface defined around the orifice; and a first cover having a contact surface in slideable and sealing engagement with the first surface of the seat member and moveable with respect to the seat member to provide an open and a closed position, the first cover extending less than a full circumference of the tubing, the contact surface of the first cover and the first surface of the seat member cooperable to provide a face-to-face fluid seal, wherein the orifice has a first side and a second side, the first cover being provided on the first side of the orifice, the downhole valve assembly further comprising a second cover on the second side of the orifice.
- 3. The valve assembly of claim 2, wherein the first cover and seat member each comprises a material having a low coefficient of friction.
- 4. The valve assembly of claim 3, wherein the material includes polycrystalline-coated diamond.
- 5. The valve assembly of claim 3, wherein the material is selected from the group consisting of vapor deposition diamond, ceramic, silicon nitride, carbide, and a cobalt-based alloy.
- 6. The valve assembly of claim 2, wherein the second cover is slideably disposed over the second side of the orifice to provide an open position and a closed position.
- 7. The valve assembly of claim 6, further comprising a second seat member comprising a second surface defined around the second side of the orifice, the second cover having a contact surface in slideable and sealing engagement with the second surface of the second seat member.
- 8. A downhole valve for controlling flow through an orifice defined in a wall of a tubular structure, comprising:a first surface defined about the orifice; a cover adapted to slide to and between an open position and a closed position, the cover sealably closing the orifice when in the closed position and exposing at least a portion of the orifice when in the open position; the cover having a contact surface adapted to slideably and sealingly engage the first surface to form a face-to-face fluid seal when the cover is in the closed position; and a spring attached to push the cover contact surface against the first surface.
- 9. The valve of claim 8, wherein the contact surface engages the first surface along a periphery when the cover is in the closed position, the seal being formed around the periphery.
- 10. The valve of claim 8, wherein each of the cover contact surface and first surface comprises a material having a low coefficient of friction.
- 11. The downhole valve of claim 8, wherein the contact surface of the cover is adapted to slide over the first surface between the open position and the closed position.
- 12. The downhole valve of claim 8, wherein the cover is adapted to be set at an intermediate position between the open position and the closed position to provide a partially open position of the valve.
- 13. A downhole valve assembly for controlling flow through an opening defined in a first surface, comprising:a cover member having a contact surface in slideable and sealing engagement with the first surface, the cover member further including a tapered lower edge that is adapted to remove debris from the first surface.
- 14. The valve assembly of claim 13, wherein the tapered lower edge protrudes outwardly from a side of the cover member.
- 15. The valve assembly of claim 13 wherein the tapered lower edge has an inclined surface.
- 16. The valve assembly of claim 13, wherein the tapered lower edge faces in a direction along an axis of movement of the cover member.
- 17. A valve for controlling fluid flow through at least one orifice in a wall of a downhole tubing that has a circumference, comprising:a seat defined about the at least one orifice; and at least one cover selectively positionable at and between an open position and a closed position, the at least one cover slideably and sealingly engaging the seat, the at least one cover having a sealing surface that cooperates with a surface of the seat to form a face-to-face fluid seal, the at least one cover extending less than the full circumference of the tubing, wherein the cover sealing surface and the seat surface are adapted to provide the fluid seal without use of a separate sealing element.
- 18. The valve of claim 17, further comprising a spring element adapted to push the sealing surface of the cover against the seat surface.
- 19. A downhole valve assembly for controlling fluid flow through an orifice defined in a side of a tubing, comprising:a seat member comprising a first surface defined around the orifice; and a first cover having a contact surface in slideable and scaling engagement with the first surface of the seat member and moveable with respect to the seat member to provide an open and a closed position, the first cover extending less than a full circumference of the tubing, the contact surface of the first cover and the first surface of the seat member cooperable to provide a face-to-face fluid seal, wherein the contact surface of the first cover and the first surface of the seat member are adapted to provide the fluid seal without a separate sealing element.
- 20. The valve assembly of claim 19, further comprising a spring element adapted to push the contact surface of the first cover against the first surface of the seat member.
- 21. A downhole valve assembly for controlling fluid flow through an orifice defined in a side of a tubing, comprising:a seat member comprising a first surface defined around the orifice; and a first cover having a contact surface in slideable and sealing engagement with the first surface of the seat member and moveable with respect to the seat member to provide an open and a closed position, the first cover extending less than a full circumference of the tubing; the contact surface of the first cover and the first surface of the seat member cooperable to provide a face-to-face fluid seal; and plural carriers each supporting one of the corresponding covers, the carriers being attached.
- 22. The valve assembly of claim 21, further comprising an actuator mechanism adapted to move the carriers.
- 23. A downhole valve assembly for controlling fluid flow through an orifice defined in a side of a tubing, comprising:a seat member comprising a first surface defined around the orifice; and a first cover having a contact surface in slideable and sealing engagement with the first surface of the seat member and moveable with respect to the seat member to provide an open and a closed position, the first cover extending less than a full circumference of the tubing, the contact surface of the first cover and the first surface of the seat member cooperable to provide a face-to-face fluid seal, wherein the tubing defines at least one other orifice, the valve assembly further comprising at least one other cover adapted to control flow through the at least one other orifice, wherein the first orifice and the at least one other orifice have different flow areas.
- 24. A method of making a valve assembly for use with a tubing having a wall with an opening, the method comprising:forming a seat having a first surface definable about the opening in the wall of the tubing; mounting at least one cover relative to the seat so that the cover is moveable relative to the opening; and forming a contact surface on the cover to slideably and sealingly engage the first surface of the seat to form a face-to-face fluid seal when the contact surface completely covers the opening, wherein forming the face-to-face fluid seal is provided without use of a separate seal element.
- 25. A valve to control flow through an orifice, comprising:a first surface on a first side of the orifice and a second surface on a second side of the orifice; a first cover adapted to slideably and scalingly engage the first surface, the first cover slideable over the first surface; and a second cover adapted to slideably and scalingly engage the second surface, the second cover slideable over the second surface.
- 26. The valve of claim 25, further comprising a member attaching the first and second covers to enable movement of the first and second covers together.
- 27. The valve of claim 25, further comprising at least one additional first cover slideable over a first side of at least one other orifice and at least one additional second cover slideable over a second side of the at least one other orifice.
- 28. A valve assembly comprising:a first surface defining an orifice; a cover having a sealing surface adapted to slideably and sealingly engage the first surface to provide an open position and closed position of the valve; and an element adapted to push the cover sealing surface against the first surface to enhance sealing engagement between the cover sealing surface and the first surface.
- 29. The valve assembly of claim 28, wherein the cover is slideable over the first surface between the open position and the closed position.
- 30. The valve assembly of claim 28, wherein the element comprises a spring.
- 31. The valve assembly of claim 28, further comprising an actuator adapted to move the cover between the open and closed position, the actuator further adapted to set the cover at an intermediate position between the open and closed positions.
US Referenced Citations (21)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0 615 054 A |
Sep 1994 |
EP |
2 261 719 A |
May 1993 |
GB |