U.S. patent application number 09/789139 was filed with the patent office on 2001-09-27 for lubricator for underbalanced drilling.
Invention is credited to Patel, Dinesh R..
Application Number | 20010023764 09/789139 |
Document ID | / |
Family ID | 26840917 |
Filed Date | 2001-09-27 |
United States Patent
Application |
20010023764 |
Kind Code |
A1 |
Patel, Dinesh R. |
September 27, 2001 |
Lubricator for underbalanced drilling
Abstract
A system usable with a subterranean well includes a tubing and a
lubricator. The tubing is adapted to receive a drill string in a
passageway of the tubing, and the lubricator is located downhole
and is connected to the tubing. The lubricator is adapted to be
remotely operable from a surface of the well to control fluid
communication between the passageway located above the lubricator
and a formation located beneath the lubricator. The lubricator may
include a sleeve and controller. The controller selectively moves
the sleeve into a passageway of a valve of the lubricator to
protect the valve from a downhole fluid.
Inventors: |
Patel, Dinesh R.; (Sugar
Land, TX) |
Correspondence
Address: |
Jeffrey E. Griffin
Schlumberger Technology Corporation
Schlumberger Perforating and Testing Center
P.O. Box 1590
Rosharon
TX
77583-1590
US
|
Family ID: |
26840917 |
Appl. No.: |
09/789139 |
Filed: |
February 20, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09789139 |
Feb 20, 2001 |
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09531945 |
Mar 21, 2000 |
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6250383 |
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60143322 |
Jul 12, 1999 |
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Current U.S.
Class: |
166/375 ;
166/321; 166/386; 166/69; 166/70; 166/72 |
Current CPC
Class: |
E21B 21/10 20130101;
Y10T 137/86944 20150401; E21B 34/108 20130101; E21B 34/102
20130101; E21B 34/101 20130101; E21B 33/10 20130101; E21B 21/085
20200501; E21B 23/006 20130101; E21B 2200/04 20200501 |
Class at
Publication: |
166/375 ;
166/386; 166/72; 166/69; 166/70; 166/321 |
International
Class: |
E21B 034/10; E21B
023/00 |
Claims
What is claimed is:
1. A system usable with a subterranean well, comprising: a tubing
adapted to receive a drill string in a passageway of the tubing;
and a lubricator located downhole away from a surface of the well
and connected to the tubing, the lubricator adapted to receive the
drill string and be remotely operable from a surface of the well to
control fluid communication between the passageway located above
the lubricator and a formation located beneath the lubricator.
2. The system of claim 1, wherein the lubricator is located at
least one thousand feet from the surface of the well.
3. The system of claim 1, wherein the lubricator is adapted to
permit an operator to select whether the lubricator defaults to an
open or a closed position.
4. The system of claim 1, wherein the lubricator comprises at least
two ball valves coupled to operate in synchronization.
5. The system of claim 1, wherein the lubricator is further adapted
to respond to pressure changes in an annulus that surrounds the
lubricator.
6. The system of claim 5, wherein the lubricator is further adapted
to respond to a predetermined sequence of pressure changes before
isolating the passageway above the lubricator from the
formation.
7. The system of claim 1, wherein the lubricator is adapted to
respond to a pressure controllable from the surface to control the
fluid communication between the passageway located above the
lubricator and the formation located beneath the lubricator.
8. The system of claim 7, wherein the lubricator is adapted to
close the communication in response to a decrease in the
pressure.
9. The system of claim 7, wherein the lubricator is adapted to open
the communication in response to a decrease in the pressure.
10. The system of claim 1, wherein the lubricator comprises: a
valve positioned to control the communication; and an operator
mandrel connected to open and close the valve in response to a
stimuli communicated from the surface of the well.
11. The system of claim 10, wherein the stimuli comprises a
pressure change in a second fluid.
12. The system of claim 11, wherein the operator is adapted to move
to close the valve in response to the pressure in the second fluid
decreasing.
13. The system of claim 11, wherein the operator is adapted to move
to open the valve in response to the pressure in the second fluid
decreasing.
14. The system of claim 10, wherein the lubricator further
comprises: a hold close mechanism to prevent unintentional opening
of the valve.
15. The system of claim 1, wherein the lubricator comprises: a
valve adapted to open and close the communication.
16. The system of claim 15, wherein the valve comprises a ball
valve.
17. The system of claim 15, wherein the valve includes a central
passageway for communicating the fluid, the lubricator further
comprising: a sleeve adapted to selectively move inside the central
passageway to protect the valve.
18. The system of claim 17, wherein the sleeve is adapted to move
in the central passageway in response to the opening of the
valve.
19. The system of claim 17, wherein the sleeve is adapted to move
out of the central passageway in response to the opening of the
valve.
20. The system of claim 17, wherein the lubricator further
comprises: an operator mandrel to move the sleeve in response to a
pressure stimuli controllable form the surface of the well.
21. The system of claim 20, wherein the lubricator further
comprises: a gas metering device adapted to delay the response of
the operator mandrel to prevent the sleeve from moving into the
central passageway of the valve before the valve opens.
22. The system of claim 20, wherein the valve is adapted to respond
to the pressure stimuli, the lubricator further comprising: a
pressure relief valve adapted to establish a first range of
pressures for controlling the valve and a second range of pressures
for controlling the sleeve.
23. An apparatus usable with a well, comprising: a sleeve; a ball
valve having central passageway; and a controller to selectively
move the sleeve into the passageway to protect at least a portion
of the ball valve.
24. The apparatus of claim 23, wherein the sleeve protects the ball
valve from abrasion introduced by a drilling fluid.
25. The apparatus of claim 23, wherein the sleeve is adapted to
move in the central passageway in response to the opening of the
valve.
26. The apparatus of claim 23, wherein the sleeve is adapted to
move out of the central passageway in response to the opening of
the valve.
27. The apparatus of claim 23, further comprising: an operator
mandrel to move the sleeve in response to a stimuli controllable
form the surface of the well.
28. The apparatus of claim 27, wherein the stimuli comprises a
pressure stimuli.
29. The apparatus of claim 28, wherein the lubricator further
comprises: a gas metering device adapted to delay the response of
the operator mandrel to prevent the sleeve from moving into the
central passageway of the valve before the valve opens.
30. The apparatus of claim 28, wherein the valve is adapted to
respond to the pressure stimuli, the lubricator further comprising:
a pressure relief valve adapted to establish a first range of
pressures for controlling the valve and a second range of pressures
for controlling the sleeve.
31. A method usable with a subterranean well, comprising: providing
a tubing to receive a drill string in a passageway of the tubing;
and remotely operating a downhole valve that is located away from a
surface of the well to control fluid communication between the
passageway located above the lubricator and a formation located
beneath the lubricator.
32. The method of claim 31, wherein the valve is located a distance
greater than one thousand feet downhole from the surface.
33. The method of claim 31, wherein the operating comprises:
communicating pressure changes to an annulus that surrounds the
lubricator.
34. The method of claim 31, wherein the operating comprises:
closing the communication in response to a decrease in the
pressure.
35. The method of claim 31, wherein the operating comprises:
opening the communication in response to a decrease in the
pressure.
36. The method of claim 35, wherein the operating further
comprises: preventing the opening of the communication before a
hold close mechanism is released.
37. The method of claim 31, further comprising: selectively moving
a sleeve inside a central passageway of the lubricator to protect
the lubricator from abrasion introduced by a fluid that flows
through the central passageway.
38. The method of claim 37, wherein the fluid is associated with
drilling a downhole formation.
39. The method of claim 37, wherein the moving comprises: moving
the sleeve into the central passageway in response to the opening
of the valve.
40. The method of claim 37, wherein the moving comprises: moving
the sleeve into the central passageway in response to the opening
of the valve.
41. The method of claim 37, wherein the moving comprises: moving
the sleeve out from the central passageway in response to the
opening of the valve.
42. The method of claim 37, wherein the operating comprises moving
the sleeve into the central passageway in response to the opening
of the valve, the method further comprising: delaying the movement
of the sleeve into the central passageway to prevent the sleeve
from moving into the central passageway of the valve before the
valve opens.
43. A method usable with a subterranean well, comprising: providing
a sleeve adapted to line a passageway of a ball valve; and
selectively moving the sleeve into the passageway of the ball to
protect at least a portion of the ball valve..
44. The method of claim 43, wherein the sleeve protects said at
least a portion of the ball valve from abrasion caused by a
drilling fluid.
45. The method of claim 43, wherein the portion of the tool
comprises a valve and the passageway comprises a central passageway
of the valve.
46. The method of claim 43, wherein the valve comprises a ball
valve.
47. The method of claim 45, wherein the moving comprises: moving
the sleeve into the central passageway in response to the opening
of the valve.
48. The method of claim 45, wherein the moving comprises: moving
the sleeve into the central passageway in response to the opening
of the valve.
49. The method of claim 45, wherein the moving comprises: moving
the sleeve out from the central passageway in response to the
opening of the valve.
50. The method of claim 45, wherein the operating comprises moving
the sleeve into the central passageway in response to the opening
of the valve, the method further comprising: delaying the movement
of the sleeve into the central passageway to prevent the sleeve
from moving into the central passageway of the valve before the
valve opens.
Description
[0001] This application claims the benefit, under 35 U.S.C. .sctn.
119, to U.S. Provisional Patent Application Ser. No. 60/143,322,
entitled, "LUBRICATOR FOR UNDERBALANCED DRILLING," filed on Jul.
12, 1999.
BACKGROUND
[0002] The invention relates to a lubricator for underbalanced
drilling.
[0003] There are two techniques that typically are used to drill a
borehole in a formation: an overbalanced drilling technique and
underbalanced drilling technique. In overbalanced drilling, fluid
in an annulus of a well is used to exert a pressure that is greater
than the formation pressure. Thus, the pressure that is exerted by
the annulus fluid keeps formation fluids from exiting the well. A
drawback to this technique is that mud particles typically are
added to the annulus fluid to increase its weight (and thus,
increase its downhole pressure), and these mud particles tend to
clog up openings in the formation. Thus, the formation may be
damaged by overbalanced drilling, and after drilling, cleanup of
the well may be needed before production begins. The well may also
need to be tested after overbalanced drilling to check for
formation damage.
[0004] Unlike overbalanced drilling, underbalanced drilling
typically does not damage the formation damage and typically
maximizes reservoir inflow. In underbalanced drilling, heavy
annulus fluid is not used to suppress the formation pressure.
Instead, a blowout preventer, or snubbing unit, is used to seal off
the drill string at the surface of the well. However, this
arrangement may also present difficulties. For example, when
drilling at shallow depths or retrieving the drill string, the
upward force from the formation pressure may exceed the weight of
the drill string and thus, may force the drill string out of the
borehole. As a result, retrieving the drill string may consume a
considerable amount of time and present a significant danger.
[0005] Thus, there is a continuing need for an arrangement to
address one or more of the problems that are stated above.
SUMMARY
[0006] In an embodiment of the invention, a system usable with a
subterranean well includes a tubing and a lubricator. The tubing is
adapted to receive a drill string in a passageway of the tubing,
and the lubricator is located downhole and is connected to the
tubing. The lubricator is adapted to be remotely operable from a
surface of the well to control fluid communication between the
passageway located above the lubricator and a formation located
beneath the lubricator.
[0007] In another embodiment of the invention, an apparatus that is
usable with a downhole tool that has a passageway includes a sleeve
and a controller. The controller selectively moves the sleeve into
the passageway to protect a portion of the downhole tool from a
downhole fluid.
[0008] Advantages and other features of the invention will become
apparent from the following description, drawing and claims.
BRIEF DESCRIPTION OF THE DRAWING
[0009] FIG. 1 is a schematic diagram of a subterranean well
according to an embodiment of the invention.
[0010] FIG. 2 is a cross-sectional view of a lubricator according
to an embodiment of the invention.
[0011] FIGS. 3 and 4 are cross-sectional views of a lubricator
according to an embodiment of the invention.
[0012] FIG. 5 is a cross-sectional view of the lubricator of FIGS.
3 and 4 taken along line 5-5 of FIG. 3.
[0013] FIG. 6 is a schematic diagram of a J-slot of the lubricator
of FIGS. 3 and 4.
[0014] FIGS. 7, 8, 9, 10, 11, 12, 13, 14, 15 and 16 are schematic
diagrams illustrating different operational states of the
lubricator of FIGS. 3 and 4.
[0015] FIGS. 17 and 18 are cross-sectional views of a lubricator
according to an embodiment of the invention.
[0016] FIG. 19 is a cross-sectional view of a lubricator according
to an embodiment of the invention.
[0017] FIGS. 20 and 21 are schematic diagrams of wells according to
different embodiments of the invention.
[0018] FIG. 22 is a cross-sectional view of a lubricator according
to an embodiment of the invention.
[0019] FIG. 23 is a flow diagram depicting an algorithm to close a
ball valve of the lubricator according to an embodiment of the
invention.
[0020] FIG. 24 is a flow diagram depicting an algorithm to open a
ball valve of the lubricator according to an embodiment of the
invention.
[0021] FIG. 25 is a cross-sectional view of a portion of a
lubricator valve according to an embodiment of the invention.
DETAILED DESCRIPTION
[0022] Referring to FIG. 1, in a subterranean well 5, an embodiment
20 of a downhole lubricator in accordance with the invention may be
used for underbalanced drilling. When a drill pipe, or string 10,
is inserted through a central passageway of the lubricator 20, the
lubricator 20 forms a seal between an annulus 19 that is formed
from the exterior surface of the string 10 and the interior surface
of a concentric tubing 16. When the drill string 10 is withdrawn
from the lubricator 20, the lubricator 20 may be remotely operated
from the surface of the well 5 to selectively seal off its central
passageway. In this manner, the lubricator 20 may either be open to
allow the drill string 10 to be inserted downhole through the
central passageway of the lubricator 20 (as depicted in FIG. 1) or
closed to seal off the formation(s) below the lubricator 20 from
the portion of the well 5 that is located above the lubricator
20.
[0023] Because the design of the lubricator 20 permits the
lubricator 20 to be positioned a sufficient distance (approximately
one to three thousand feet, for example) downhole, the lubricator
20 may be advantageous for shallow drilling or for retrieval of the
drill string 10 from the borehole. For example, during retrieval of
the drill string 10, the lubricator 20 may be used to seal off the
formation that is beneath the drill string 10 before the drill
string 10 is otherwise shallow enough to cause the formation
pressure to overcome the weight of the drill string 10 and thus,
force the drill string 10 out of the borehole. As described further
below, depending on the particular embodiment, the lubricator 20
may be selectively opened or closed by manipulating the pressure of
fluid in an annulus of the well or by varying a pressure on a
pressure control line. Safety features that accompany these
controls are also described below. As examples of these features,
the lubricator may include redundant inline ball valves (described
below) to minimize the risk of potential seal failure and a hold
close mechanism to prevent accidental opening of the
lubricator.
[0024] As depicted in FIG. 1, the borehole of the subterranean well
5 may be partially cased by a casing 12 that is formed from
telescopic sections, such as sections 12a and 12b, as examples. The
tubing 16 may also be formed from telescopic sections, such as
sections 16a and 16b, as examples, and be inserted into the central
passageway of the casing 12. An annular seal, or packer 23, may
form a seal between the exterior of the drill pipe 10 and the
interior of the tubing 16 and form an annulus 21. A drill bit 14 of
the drill string 10 may extend beyond the tubing 16 into the
formation being currently drilled.
[0025] FIG. 2 generally depicts one-half of the lubricator 20. As
shown, the lubricator 20 may include an operator mandrel 34 that
may be actuated by annulus fluid pressure to operate an upper
inline ball valve 30 and a lower inline ball valve 32, both of
which are situated in a central passageway 27 of the lubricator 20.
In some embodiments, the ball valves 30 and 32 may be closed when
no pressure is applied to the fluid in the annulus 21 (see FIG. 1).
In this manner, the fluid in the annulus 21 may (via a radial port
38) contact a lower surface 48 of a piston head 46 of the operator
mandrel 34, and an upper surface 50 of the piston head 46 may
contact a spring 40. When no surface pressure is applied to the
fluid in the annulus 21, the downward force of the spring 40 on the
piston head 46 counters the upper force that is produced by the
column of fluid in the annulus 21.
[0026] However, when additional pressure is applied to the column
of fluid at the surface of the well 5, an additional upward force
is applied to the piston head 46 to cause the operator mandrel 34
to move in an upward direction and compress the spring 40. The
upward travel of the operator mandrel 34, in turn, rotates the ball
valves 30 and 32 to their open positions. When the applied surface
pressure is released, the spring 40 forces the operator mandrel 34
back down to close the ball valves 30 and 32. It is noted that the
upper end of the operator mandrel 34 is coupled to a position of
the ball valve 30 that is different than a position to which a
lower end of the operator mandrel 34 is coupled. These connection
differences cause both ball valves 30 and 32 to open in response to
the upward travel of the operator mandrel 34 and to close in
response to the downward travel of the operator mandrel 34.
[0027] Alternatively, in other embodiments, the operator mandrel 34
may be connected to the ball valves 30 and 32 in a manner that
causes the ball valves 30 and 32 to both be open when no surface
pressure is applied to the fluid in the annulus 21 and cause both
ball valves 30 and 32 to be closed when surface pressure is applied
to the annulus 21. An alternative embodiment 70 described in
conjunction with FIGS. 3 and 4 below includes a hold close
mechanism to prevent unintentional opening of the ball valves 30
and 32 due to a temporary release, or bleeding off, of annulus
pressure (due to a failure at the surface of the well, for
example).
[0028] Among the other features of the lubricator 20, in some
embodiments, the lubricator 20 may include an outer housing 42 that
includes a generally cylindrical upper section 50 that has threads
for connecting the lubricator 20 inline with the tubing 16. A
mandrel 52 of the housing 42 is threadably coupled to the bottom of
the upper section 50 between the upper section 50 and a generally
cylindrical middle section 54 of the housing 42. The mandrel 52, in
combination with the exterior of the operator mandrel 34 and the
interior of the middle section 54, forms a chamber 60 for housing
the spring 40. As an example, the chamber 60 may be filled with a
gas, such as Nitrogen (for example), that aids in pressurizing the
chamber 60 and thus, contributing to the force that is exerted
against the operator mandrel 34. In other embodiments, other
balancing techniques may be used. For example, the chamber 60 may
include the spring 40 and not contain a pressurized gas.
Alternatively, the chamber 60 may contain a pressurized gas and not
include the spring 40. As another example, in some embodiments,
annulus pressure may be used in the balancing, and as yet another
example, two pressure conveying control lines may be extended from
the surface of the well for purposes of controlling the operator
mandrel 34. Other pressure balancing arrangements are possible that
may be used with the lubricator 20 or with the lubricators
described below.
[0029] Another mandrel 55 of the housing 42 is coupled between the
middle section 54 and a generally cylindrical lower section 56 of
the housing 42. The mandrel 55, in combination with the exterior of
the operator mandrel 34 and the interior of the middle section 54,
forms a chamber 44 for receiving the annulus fluid that contacts
the lower surface 48 of the piston head 46. The radial port 38 may
be formed in the middle section 54. The lubricator 20 may also
include O-rings to establish seals for the chambers 44 and 50 and
to generally seal off the annulus 21 from the central passageway 27
of the lubricator 70.
[0030] For the lubricator 20, continuous annulus pressure must be
applied to keep the ball valves 30 and 32 opened or closed,
depending on the particular embodiment. Referring to FIGS. 3 and 4,
in another embodiment, a lubricator 70 may be used in place of the
lubricator 20. Unlike the lubricator 20, the lubricator 70 has a
hold close mechanism that keeps the ball valves 30 and 32 closed
(for example) after pressure in the annulus 21 (see FIG. 1) is bled
off, or released. More particularly, in some embodiments, the
lubricator 70 includes an index mandrel 76 that tends to travel in
an upward direction in response to pressure in the annulus 21. In
this manner, referring to FIG. 3, when the index mandrel 76 travels
a sufficient distance uphole, a lower radial extension 80 of the
index mandrel 76 catches a lug 78 of a lower operator mandrel 81
and causes the operator mandrel 81 to travel in an upward direction
and close a lower ball valve 72. Similarly, referring to FIG. 4,
when the index mandrel 76 has traveled a sufficient distance
uphole, an upper radial extension 98 of the index mandrel 76 pushes
against a shoulder 105 of an upper operator mandrel 102 to cause
the operator mandrel 102 to travel in an upward direction and close
an upper ball valve 72. A spring 94 exerts a downward force on a
shoulder 95 of the index mandrel 76, a force that may tend to keep
the ball valves 70 and 72 open in the absence of sufficient annulus
pressure if not for the hold close mechanism that is described
below.
[0031] The hold close mechanism operates in the following manner to
keep the ball valves 72 and 74 closed, even if pressure is bled off
of the annulus 21. When the index mandrel 76 travels in an upward
direction to close the ball valves 72 and 74, outward radial
extensions 92 (one being shown in FIG. 3) of the index mandrel 76
slides past an index sleeve 82 that circumscribes the index mandrel
76. However, the upward travel of the index mandrel 76 causes the
index sleeve 82 to rotate and prevent the extensions 92 from
passing through the sleeve 82 on the mandrel's downward path.
Therefore, if the applied annulus pressure is released, the index
sleeve 82 prevents the index mandrel 76 from traveling further
downhole, an action that would otherwise open the ball valves 72
and 74. To open the ball valves, surface pressure must be reapplied
to the annulus 21 to cause the index mandrel 76 to travel uphole,
an action that cause the index sleeve 82 to rotate to a position
that allows the extensions 92 to pass through when pressure is
subsequently bled off the annulus 21. In this manner, when pressure
is removed from the annulus 21, the index sleeve 82 permits the
index mandrel 76 to travel downhole to open the ball valves 72 and
74. In some embodiments, the above-described open and close cycle
is repeatable. Thus, to summarize in some embodiments, pressure is
applied to the annulus 21 to close the ball valves 72 and 74. To
open the ball valves 72 and 74, the pressure must be released, then
reapplied and then released.
[0032] Referring to FIG. 5, in some embodiments, the index sleeve
82 includes splines 114 that, when aligned with the extensions 92,
halt the downward travel of the index mandrel 76. The index sleeve
82 also includes channels 116 that, when aligned with the
extensions 92, allow the extensions 92 to pass through. Each time
the index mandrel 76 travels uphole, the index sleeve 82 rotates by
a predetermined angle (30.degree., 60.degree. or 90.degree. (as
depicted in FIG. 5), as examples) to align the extensions 92 with
either the channels 116 or the splines 114. In some embodiments,
the rotation of the index sleeve 82 is accomplished via an index
pin 84 and J-slot 112 (see FIG. 6) arrangement. In this manner,
referring to FIG. 6, a portion 110 of the index mandrel 76 may
include the slot 112 that serves as a guide for the index pin 84
that is partially disposed therein. The index pin 84 may be
partially seated in one of the splines 114. Because the index
mandrel 76 is confined not to rotate, the travel of the index pin
84 through the slot 112 causes the index sleeve 82 to rotate, as
described above.
[0033] FIGS. 7, 8, 9, 10 and 11 illustrate operation of the lower
ball valve 72. One half of the lubricator 72 is shown in each of
these figures. FIG. 7 depicts the scenario where the lower ball
valve 72 is opened For this to occur, the index sleeve 82 is
rotated to a position where the extensions 92 of the index mandrel
76 pass through the channels 116 of the index sleeve 82. As shown,
the lower extension 80 of the index mandrel 76 contacts a shoulder
83 of the lower operator mandrel 81 to cause the operator mandrel
81 to open the lower ball valve 72.
[0034] FIG. 8 depicts a scenario when the lower ball valve 72 is
closed. In this manner, for this scenario, the lower extension 80
of the index mandrel 76 catches the lug 78 and pulls the operator
mandrel 81 in an upward direction to close the ball valve 72. As
depicted in FIG. 8, the extensions 92 pass through the channels 116
of the index sleeve 82. However, the upward travel of the index
mandrel 76 causes the index sleeve 82 to rotate by a predetermined
angle (30.degree., 60.degree. or 90.degree., as examples), and as a
result, the extensions 92 are aligned with the splines 114, as
depicted in FIG. 9. Thus, downward travel of the index mandrel 76
(and opening of the lower ball valve 74) is prevented, even if the
applied annulus pressure is released.
[0035] At this point, to open the lower ball valve 74, pressure is
bled off the annulus 21 and then reapplied to cause the index
mandrel 82 to move in an upward direction, as depicted in FIG. 10.
The upward travel of the index mandrel 82 causes the index sleeve
82 to rotate by a predetermined angle (30.degree., 60.degree. or
90.degree., as examples) to a position where the extensions 92 of
the index mandrel 76 may pass through the channels 114 of the index
sleeve 82 and thus, permit the lower ball valve 74 to close, as
depicted in FIG. 11.
[0036] The upper ball valve 74 opens and closes with the lower ball
valve 72. FIGS. 12, 13, 14, 15 and 16 illustrate operation of the
upper ball valve 74. One half of the lubricator 72 is shown in each
of these figures. FIG. 12 depicts the scenario where the upper ball
valve 74 is opened. As shown, the upper extension 98 of the index
mandrel 76 grabs a lug 100 of the upper operator mandrel 102 to
cause the operator mandrel 102 to open the upper ball valve 74.
[0037] FIG. 13 depicts a scenario when the upper ball valve 74 is
close. In this manner, for this scenario, the upper extension 98 of
the index mandrel 76 contacts a shoulder 105 of the upper operator
mandrel 102 and pushes the operator mandrel 102 in an upward
direction to close the ball valve 74. To reopen the ball valve 74,
the above-described procedure is initiated to release the hold
close mechanism that is depicted in FIG. 14. In this manner, to
open the upper ball valve 74, pressure is bled off the annulus 21
and then reapplied to cause the index mandrel 82 to move in an
upward direction, as depicted in FIG. 15. The upward travel of the
index mandrel 82 causes the index sleeve 82 to rotate by a
predetermined angle (30.degree., 60.degree. or 90.degree., as
examples) to a position where the extensions 92 of the index
mandrel 76 may pass through the channels 114 of the index sleeve 82
and thus, permit the upper ball valve 74 to close, as depicted in
FIG. 16.
[0038] Referring back to FIGS. 3 and 4, among the other features of
the lubricator 70, the lubricator 70 may include an outer housing
that is formed from generally cylindrical housing sections 79, 77,
75, 73 and 71 that are threadly connected (for example) together.
The housing section 75 may form a chamber for the spring 94 and a
chamber 91 that communicates with a radial port 88 that is formed
in the section. The radial port 88 establishes fluid communication
between the annulus 21 and the chamber 91 that, in turn, places a
shoulder 90 of the index mandrel 76 in contact with the annulus
fluid. The lubricator 70 may also include O-rings and other seals
to establish seals for the chamber 91 and generally seal off the
annulus 21 from a central passageway 97 of the lubricator 70.
[0039] Referring to FIGS. 17 and 18, in some embodiments, a
lubricator 130 may be used in place of the lubricator 20 or 70. The
lubricator 130 is depicted as including a single ball valve 140
that may be operated to selectively seal off its central passageway
143. However, in some embodiments, the lubricator 130 may include
another ball valve, similar to the arrangements described above.
Alternatively, two lubricators that have single ball valves may be
stacked together in some embodiments.
[0040] In some embodiments, the lubricator 130 may include an
operator mandrel 132 that is connected to open and close the ball
valve 140. The operator mandrel 132 includes an annular piston head
134 that piston head 134 resides in an annular region of an outer
housing section 142 and forms an upper chamber 138 above the piston
head 134 and a lower chamber 136 below the piston head 134. Via a
passageway 139 in the housing section 142, the chamber 138 is in
communication with a tubular line 141 that extends to the surface
of the well 5. In this manner, the line 141 may be rapidly
pressurized with a gas (Nitrogen, for example) to exert pressure on
an upper surface 135 of the piston head 134. The piston head 134
includes a metered communication path between the upper 138 and
lower 136 chambers. However, because the flow rate of the gas
through this metered path is limited, rapid pressurization of the
gas in the upper chamber 138 exerts a net downward force on the
piston head 134, a force that moves the operator mandrel 132
downhole and opens the ball valve 140 (see FIG. 18).
[0041] Closing the ball valve 140 involves a procedure that creates
the opposite pressure imbalance between the two chambers 136 and
138 than that described above in conjunction with opening the ball
valve 140. In this manner, eventually after the ball valve 140 is
opened, the pressures in the upper 138 and lower 136 chambers
equalize due to the metered passageway that is provided by the
piston head 134. To close the ball valve 140, the line 141 may be
used to rapidly bleed off gas from the chamber 138, an event that
forces the operator mandrel 132 in an upward direction due to open
the inability of the metered passageway to instantaneously equalize
the pressures in the two chambers 136 and 138.
[0042] Among the other features of the lubricator 130, the
lubricator 130 may include another cylindrical housing section 144
that is threadably coupled to the upper section 142. The lubricator
130 may also include also include O-rings and other seals to
establish seals for the chambers 136 and 138 and to generally seal
off the annulus 21 from the central passageway 141 of the
lubricator 130.
[0043] In some embodiments, the above-described lubricators may be
replaced by a lubricator 160 that is depicted in FIG. 19. The
lubricator 160 is similar to the lubricator 130 except for the
features noted below. In particular, in the lubricator 160, the
line 141 is replaced with a radial port 162 that establishes
communication between the annulus 21 and a chamber 164 of the
lubricator 160. Thus, pressure at the surface of the well may be
applied to the annulus 21 for purposes of opening and closing the
ball valve 140. In this manner, the chamber 164 is formed in part
by the annular region that establishes the chambers 136 and 138. A
radial port 165 establishes fluid communication between the annulus
21 and the chamber 164. An unattached annular piston 166 separates
the chambers 164 and 136, and chambers 136 and 138 contain a gas,
such as Nitrogen. Therefore, when pressure is rapidly applied to
the annulus 21, the fluid from the annulus 21 forces the piston 166
upwards. The upward travel of the piston 166, in turn, forces the
operator mandrel 132 in an upward direction, as the metering
passageway in the piston head 134 does not communicate the gas
between the chambers 136 and 138 in a rapid enough manner to
prevent the pressure imbalance. The upward travel of the operator
mandrel 132, in turn, closes the ball valve 140.
[0044] The ball valve 140 may be opened by rapidly bleeding
pressure from the annulus 21 to cause a pressure imbalance between
the chambers 136 and 138 to force the operator mandrel 132 in a
downward direction.
[0045] Referring back to FIG. 1, in the well 5 described above, the
lubricator 20 is permanently connected to the tubing 16. Due to
this arrangement, the entire tubing 16 must be removed before other
operations, such as measurements, are performed. Referring to FIG.
20, in another well 200, a tubing 202 (that replaces the tubing 16)
may have a stabbing connector assembly 204 connected to its
downhole end. In this manner, the assembly 204 may be used to stab
a seal assembly into a polished bore receptacle (PBR) 211 that is
coupled to the lubricator 130 (for example) that, in turn, is
further coupled to additional tubing 214 that extends downhole. The
assembly 204 may include a passageway 208 that establishes fluid
communication between the line 141, a passageway 210 of the PBR 211
and the lubricator 20. Thus, due to this arrangement, the tubing
202 may be removed while the lubricator 20 and the tubing 214 are
left downhole.
[0046] Referring to FIG. 21, in another well 250, a lubricator
(such as the lubricators 20, 70 and 160, as examples) that is
controlled by annulus pressure may be arranged in the following
manner. The lubricator may be permanently coupled and
concentrically aligned with tubing 256 that extends downhole of the
lubricator. The annular space between the tubing 256 and a casing
255 that surrounds the tubing 256 is sealed to form an annulus for
communicating with the lubricator. A liner 257 may also be sealed
and secured to the inside of the well casing 255 and reside below
the tubing 256. A production pipe 258 may be located below the
liner 257 and connected to provide production fluid to the central
passageway of the tubing 256. Above the lubricator, an upper tubing
252 may extend to the surface of the well 250. The upper tubing 252
rests and is sealed to a flange 253 that is formed in the upper end
of the tubing 254. Due to this arrangement, the upper tubing 252
may be removed from the well 250, and the lubricator and tubing 254
remain downhole.
[0047] Referring to FIG. 22, in some embodiments of the invention,
a lubricator 300 may be used in place of the lubricators that are
depicted above. Unlike these other lubricators, the lubricator 300
includes a protective sleeve 342 to protect a ball valve 340 of the
lubricator 300 from drilling related debris, such as drilling fluid
and cuttings, for example. In this manner, as described below,
after the lubricator 300 opens the ball valve 340, the lubricator
300 moves the sleeve 342 into an up position in which the sleeve is
located in the central passageway 341 of the ball valve 340; and
before the lubricator 300 closes the ball valve 340, the lubricator
300 moves the sleeve 342 to a down position, a position that
permits the ball valve 340 to rotate and close.
[0048] More specifically, in some embodiments of the invention, the
lubricator 300 operates the ball valve 340 and sleeve 342 in
response to the pressure that is applied via a control line that
extends from a surface of the well to an internal passageway 308 of
the lubricator 300. In some embodiments of the invention, the
control line may be filled with nitrogen gas that is pressurized
and de-pressurized, as described below, to control operation of the
ball valve 340 and sleeve 342.
[0049] For purposes of operating the ball valve 340, the lubricator
300 includes an operator mandrel 325 includes a generally
cylindrical portion 323 that is aligned with the longitudinal axis
of the lubricator 300 and is connected (via another cylindrical
portion 327 that is aligned with the longitudinal axis of the
lubricator 300) to the ball valve 340. Due to this arrangement,
when the operator mandrel 325 moves in an upward direction, the
ball valve 340 closes to block fluid flow through the central
passageway of the lubricator 300. When the operator mandrel 325
moves in a downward direction, the ball valve 340 opens to align
its central passageway with the central passageway of the
lubricator 300 to permit fluid communication through the ball valve
340.
[0050] For purposes of moving the operator mandrel 325, the
operator mandrel 325 includes an annular piston head 322 that
extends in a radially outward direction from the cylindrical
portion 323. The piston head 322 is located in an annular cavity
that is formed between the cylindrical portion 323 and a generally
cylindrical outer housing section 304 that circumscribes the
cylindrical portion 323. The annular cavity forms an upper cylinder
320 above the piston head 322 and a lower cylinder 324 (shown
having no volume in FIG. 22) below the piston head 322. Thus, as
depicted in FIG. 22, the volumes of the upper 320 and lower 324
chambers change with the movement of the piston head 322.
[0051] Movement of the piston head 322 (and thus, movement of the
operator mandrel 325 and ball valve 340) may be induced by changing
the pressure level in the control line that communicates with the
passageway 308, as the control line is in communication with the
passageway 308 for certain pressure levels (as described below) via
an internal passageway 318. The piston head 322 includes a metering
passageway 326 to establish communication between the upper 320 and
lower 324 chambers. Although the metering passageway 326 permits
pressure equalization between the upper 320 and lower 324 chambers
over time, the metering passageway 326 restricts the rate at which
pressure equalization occurs, allowing sudden changes to the
pressure in the upper chamber 320 to control movement of the
operator mandrel 325 and thus, control operation of the ball valve
340, as described below.
[0052] To manipulate the pressure that is applied to the upper
chamber 320 for purposes of operating the ball valve 340 and sleeve
342 (as described further below), the lubricator 300 includes a
relief valve 314 that is located between the passageway 308 and the
chamber 320. The relief valve 314 opens to permit communicate of
fluid between the passageway 308 and the chamber 320 when the
pressure in the passageway 308 exceeds a predetermined threshold,
such as 1500 pounds per square inch (psi), for example. In some
embodiments of the invention, the threshold for the relief valve
314 is set slightly higher than the fluid hydrostatic pressure in
the annulus. This assures that the ball valve 340 remains in its
current position in case of control line failure at any depth. The
lubricator valve 300 also includes a check valve 316 that is
located between the passageway 308 and the chamber 320 and is in a
parallel arrangement with the relief valve 314. The check valve 316
provides a path to communicate fluid away from the upper chamber
320 to bleed off pressure from the upper chamber 320 to control
movement of the operator mandrel 325, as described below.
[0053] The following describes a technique to close the ball valve
340 when the ball valve 340 is currently open. First, a
determination is made whether the control line is pressurized. If
so, then pressure in the control line is bled off through a fast
bleed port in a manifold at the surface of the well so that the
upper chamber 320 has near zero pressure. At this point, due to the
restriction that is introduced by the metering passageway 326, the
lower chamber 324 retains approximately the same pressure that
existed before de-pressurization of the control line. Thus, by
rapidly de-pressurizing the control line, a differential pressure
is created across the piston 322 to cause the operator mandrel 325
to move in an upward direction and close the ball valve 340.
[0054] If the ball valve 340 is open and the control line is not
pressurized, then the control line must first be pressurized to a
pressure that is to slightly higher than the threshold of the
relief valve 314. The increased pressure is maintained, or held,
for a holding period, such as 5 to 10 minutes, for example. The
holding period allows sufficient time from the pressures in the two
chambers 320 and 324 to equalize. After this holding period, the
control line is rapidly de-pressurized to create the differential
pressure across the piston 322 to cause the operator mandrel 325 to
move in an upward direction and close the ball valve 340, as
described above.
[0055] The following technique may be used to open the ball valve
340 when the ball valve 340 is currently closed. First, the
pressure in the tubing above the ball valve 340 is adjusted to
ensure that the pressure differential across the ball valve 340 is
less than 1000 psi. If possible, the pressure across the ball valve
340 is equalized. Next, the pressure in the control line is rapidly
increased to a pressure that is slightly higher than the relief
valve threshold pressure. For example, this increase may occur
within an interval of one to two minutes, in some embodiments of
the invention. In response to this increase, a pressure
differential is created across the piston 322 causing the operator
mandrel 325 to move and open the ball valve 340. The pressure in
the control line is then slowly bled off through a slow bleed port
in the surface manifold, for example. Because the upper chamber 320
is slowly depressurized, the metering passageway 326 keeps the
pressure differential between the upper 320 and lower 324 chambers
near zero. This by itself keeps the ball valve 340 open. However,
in some embodiments of the invention, at this point, the sleeve 342
is positioned inside the central passageway 341 of the ball valve
340 to lock the ball valve 340 in place to keep the ball valve from
closing, as described further below.
[0056] An advantage of using the above-described arrangement is
that an operator may select the position to which the ball valve
340 defaults if the pressure integrity of the control line is lost
at the surface or near the lubricator 300. For example, if the
operator wishes to keep the ball valve 340 closed even if the
control line loose pressure integrity, then the operator maintains
the control line pressure to keep the control line pressure within
the difference (500 psi, for example) of the relief valve threshold
and the pressure in the annulus. This keeps the ball valve 340
closed regardless where the control line fails. If the operator
wishes to keep the ball valve 340 open regardless if the control
line looses pressure integrity at the surface or at the lubricator
valve 300, then the operator should bleed off the control line
pressure so that no matter where the control line breaks, the ball
valve 340 remains open.
[0057] In some embodiments of the invention, the sleeve 342 is part
of an operator mandrel 330 that, in addition to the generally
cylindrical section that forms the sleeve 342, includes a piston
331 that extends in a radially outward direction into a cavity that
is formed between the operator mandrel 330 and an outer housing
section 306 of the lubricator 300. The piston 331 divides this
cavity into a chamber 328 that is in communication with the
passageway 318 and in contact with an upper face of the piston 331;
and a sealed chamber 332 that is in contact with a lower face of
the piston 331. In this manner, the sealed chamber 332 is filled
with a gas (nitrogen or air at atmospheric pressure, for example)
that exerts an upward force against the lower surface of the piston
331. Alternatively, the chamber 332 may include a spring to exert a
force against the lower surface of the piston 331. The upper face
of the piston 331 receives a force that is applied by the gas that
is present in the chamber 328. Due to this arrangement, pressure
may be applied to the gas in the control line to move the sleeve
342 to its down position out of the ball valve 340, and pressure
may be bled out of the control line to move the sleeve 342 to its
up position inside the ball valve 340.
[0058] More particularly, in some embodiments of the invention, the
lubricator 300 includes a gas metering device 310 (a gas metering
passageway, for example) that is located between the passageway 308
and an internal passageway 307 that extends to the chamber 328. As
described below, the gas metering device 310 establishes a delay to
permit the ball valve 340 to open before the sleeve 342 is inserted
into the central passageway 341 of the ball valve 340 and a delay
in the removal of the sleeve 342 from the passageway 341 to prevent
the ball valve 340 from prematurely closing, as described
below.
[0059] FIG. 23 depicts a flow diagram that illustrates a control
technique 380 to close the ball valve 340 and operate the sleeve
342 accordingly. For this example, it is assumed that the threshold
pressure of the relief valve is approximately 1500 psi, and the
sealed chamber 328 is precharged with 500 psi of gas, such as
nitrogen gas, for example. In the technique 380, the control line
is pressurized (block 381) with a pressure (2000 psi, for example)
that is greater than the threshold pressure (1500 psi, for example)
of the relief valve 314. This pressure is then held (block 384) for
a few minutes to move the sleeve 342 to its down position and set
the pressure differential between the upper 320 and lower 324
chambers to near zero. In this manner, during this period, the gas
meters through the cover sleeve gas metering device 310 and fills
the chamber 328 to pull the sleeve 342 out of the ball valve 340.
Also, during this period, the gas fills the upper chamber 320 and
then fills the lower chamber 324 through the gas metering
passageway 326. During this equalization, the operator mandrel 325
does not move down because the mandrel 325 is already in the down
position. Thus, at this point, the ball valve 340 remains open.
[0060] Next, the control line is rapidly depressurized (block 390)
by, for example, using a fast bleed port in the surface manifold.
Due to this action, the operator mandrel 325 moves to close the
ball valve 340, and the pressure in the chamber 328 slowly bleeds
off due to the gas metering device 310. When pressure in the
control line is bled off below the 500 psi level (i.e., the
pressure exerted by the gas in the sealed chamber 332 for this
example), the gas pressure in the chamber 332 forces the operator
mandrel 300 in an upward direction to push the sleeve 342 against
the ball valve 340. The ball valve 340 acts as a stop to limit
upward travel of the sleeve 342. The pressure in the control line,
the upper 320 and lower 324 chambers, and the chamber 328 then
bleeds down to atmospheric pressure after some time.
[0061] FIG. 24 depicts a flow diagram that illustrates a control
technique 400 to open the ball valve 340 and operate the sleeve 342
accordingly. In this technique, first a determination is made
(diamond 402) whether the control line is pressurized. If not,
pressure less than the relief valve pressure threshold is applied
(block 406), such as 1000 psi (for example) and held (block 408).
This action moves the sleeve 342 to its down position, as the gas
meters through the gas metering device 310 to push the sleeve 342
off of the ball valve 340.
[0062] The ball valve 340 remains closed at this point. Next,
regardless of whether the control line was initially pressurized or
not, the pressure in the control line is rapidly increased (block
404), such as increased to 2000 psi (a pressure above the relief
valve pressure of 1500 psi, as an example), to induce a pressure
imbalance between the upper 320 and lower 324 chambers to move the
operator mandrel 325 to open the ball valve 340. After some time,
the upper chamber 320, the lower chamber 324 and the chamber 328
all have the same pressure, such as a pressure near 2000 psi, for
example. Next, the control line is depressurized (block 405)
through the slow bleed port in the surface manifold, for example.
This action keeps the ball valve 340 in the open position and
permits the pressure inside the sealed chamber 332 to push the
sleeve 342 into the central passageway 341 of the ball valve 340.
In this manner, the sleeve 342 rests on a shoulder 327 that is
formed on the operator mandrel 325 to limit the upward travel of
the sleeve 342 when the ball valve 340 is open. The above-described
opening and closing of the ball valve 340 may be repeated as many
times as required.
[0063] Referring back to FIG. 22, among the other features of the
lubricator 300, the lubricator 300 may be formed from upper 302,
middle 304 and lower 306 generally cylindrical housing sections.
The passageway 308 is formed in the upper housing section 302, and
the upper housing section 302 also encloses the pressure relief
valve 314, the gas metering device 310 and the one way check valve
316. The passageway 307 extends from the gas metering device 310
through the upper 302, middle 304 and lower 306 housing sections to
the chamber 328.
[0064] Techniques other than pressure may be used to move the
sleeve operator mandrel 330. For example, FIG. 25 depicts a portion
540 of a lubricator of similar design to the lubricators that are
described above with the following exception. In this manner, the
lubricator includes a solenoid 542 that has a shaft 544 that is
connected to the operator mandrel 330. Due to this arrangement, the
solenoid 542 may be controlled (via electrical lines 546) to move
the sleeve 342 up and down as desired. As an example, the
electrical lines 546 may be connected to electronics of the
lubricator, and the electronics, may, for example control operation
of the sleeve 342 in response to pressure pulses that are
communicated downhole. Alternatively, the electrical lines 546 may
extend from the surface of the well to directly control operation
of the operator mandrel 330. Other arrangements are possible.
[0065] Other embodiments are within the scope of the following
claims. For example, the lubricator may be constructed to be
remotely controlled by arrangements other than those described
above. In this manner, the lubricator may be constructed to respond
to tubing conveyed pressure, electrical signals (via electrical
wires) and coded pressure pulses, as just a few examples of other
stimuli that may be communicated downhole. As examples of other
embodiments, the lubricator may use valves other than ball valves.
For example, the lubricator may include one or more flapper valves.
As yet another example, the lubricator and any associated control
line may be run downhole with the well casing. Therefore, the
lubricator and control line may be cemented in place with the well
casing. Thus, by using this technique, the inner diameter of the
lubricator may be increased.
[0066] While the invention has been disclosed with respect to a
limited number of embodiments, those skilled in the art, having the
benefit of this disclosure, will appreciate numerous modifications
and variations therefrom.
* * * * *