U.S. patent application number 13/659306 was filed with the patent office on 2014-04-24 for anchor latch on off for sucker rods.
This patent application is currently assigned to Weatherford/Lamb, Inc.. The applicant listed for this patent is WEATHERFORD/LAMB. INC.. Invention is credited to Jeffrey Lembcke.
Application Number | 20140110130 13/659306 |
Document ID | / |
Family ID | 49552428 |
Filed Date | 2014-04-24 |
United States Patent
Application |
20140110130 |
Kind Code |
A1 |
Lembcke; Jeffrey |
April 24, 2014 |
Anchor Latch on Off For Sucker Rods
Abstract
A device and method to allow a sucker rod to be disconnected at
a particular point in a sucker rod string. Typically the disconnect
device is located just above the barrel pump where the disconnect
device is able to provide tensile and compressive strength similar
to the sucker rod string thereby eliminating at least one failure
mode for the sucker rod string.
Inventors: |
Lembcke; Jeffrey; (Cypress,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
WEATHERFORD/LAMB. INC. |
Houston |
TX |
US |
|
|
Assignee: |
Weatherford/Lamb, Inc.
Houston
TX
|
Family ID: |
49552428 |
Appl. No.: |
13/659306 |
Filed: |
October 24, 2012 |
Current U.S.
Class: |
166/378 ;
166/72 |
Current CPC
Class: |
E21B 43/126 20130101;
E21B 17/06 20130101; E21B 17/021 20130101 |
Class at
Publication: |
166/378 ;
166/72 |
International
Class: |
E21B 23/00 20060101
E21B023/00 |
Claims
1. An apparatus for disconnecting a sucker rod comprising: an upper
section; wherein the upper section has an upper end and a lower
end; further wherein the upper end has a first threaded section and
the lower end has a second threaded section threaded in the
opposite direction of the first threaded section; a lower section;
wherein the lower section has an upper end and a lower end; further
wherein the lower end has a third threaded section and the upper
end has a fourth threaded section threaded in the opposite
direction of the third threaded section; and the second threaded
section and the fourth threaded section cooperate to join the upper
section and the lower section.
2. The apparatus for disconnecting the sucker rod of claim 1
wherein the second threaded has left hand threads and the fourth
threaded section has left hand threads.
3. The apparatus for disconnecting the sucker rod of claim 1
wherein the first threaded section is box connector and the third
threaded section is a box connector.
4. The apparatus for disconnecting the sucker rod of claim 1
wherein the upper section is a rod and the lower section is a
rod.
5. The apparatus for disconnecting the sucker rod of claim 1
wherein the upper section is a tube and the lower section is a
tube.
6. An apparatus for reconnecting a sucker rod comprising: a lower
section having an interior, an upper end, and a lower end; wherein
the interior of the lower end has a first threaded section and
interior of the upper end has a second threaded section that is
threaded in the opposite direction of the first threaded section;
an upper section having an interior, an upper end, and a lower end;
wherein the interior of the upper end has a third threaded section;
a reinforcing member having an exterior, an upper end, and a lower
end, and a recess; wherein the exterior of the upper end of the
reinforcing member is attached to the interior of the lower end of
the upper section and the exterior of the lower end of the
reinforcing member has a bias device; further wherein the recess is
located between the lower end of the upper section and the bias
device; at least one retaining collet having an interior, an
exterior, an upper end, and a lower end; wherein the exterior lower
end has a fourth threaded section that cooperates with the threads
of the second threaded section; further wherein the interior of the
lower end has a shoulder that cooperates with the bias device; and
the retaining collet is located in the recess such that the bias
device provides force in the radial outward direction against the
shoulder.
7. The apparatus for reconnecting the sucker rod of claim 6 wherein
the bias device is a ramp.
8. The apparatus for reconnecting the sucker rod of claim 6 wherein
the second threaded section has left hand threads.
9. The apparatus for reconnecting the sucker rod of claim 6 wherein
the second threaded section has right hand threads.
10. The apparatus for reconnecting the sucker rod of claim 6
wherein the second threaded section has threads that have a lower
surface that extends from the radially inward lower end of each
thread radially outward to radially outwards upper end of each
thread.
11. A method of reconnecting a sucker rod string comprising:
attaching a disconnect assembly to a sucker rod string; rotating
the sucker rod string in a first direction; removing the upper
portion of the disconnect assembly from the wellbore; attaching a
reconnect assembly to the sucker rod string; running the reconnect
assembly into a wellbore; stabbing the reconnect assembly into a
lower end of the disconnect assembly; and locking the reconnect
assembly to the lower end of the disconnect assembly.
12. The method of claim 11 wherein rotating the sucker rod string
in a first direction that is to the left.
13. The method of claim 11 wherein rotating the sucker rod string
in a first direction that is to the right.
14. The method of claim 11 wherein the reconnect assembly has an
external threaded surface.
15. The method of claim (14) wherein the external threaded surface
has threads that have a lower surface that extends from the
radially inward lower end of each thread radially outward to
radially outwards upper end of each thread.
16. The method of claim 11 wherein the reconnect assembly is locked
to the lower end of the disconnect by a bias device and a retaining
collet shoulder.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
BACKGROUND
[0001] A conventional oil well includes a cased well bore with at
least one string of tubing extending downwardly through the casing
into the oil or other petroleum fluid contained in the subsurface
mineral formation to be produced. The casing is perforated at the
level of the production zone to permit fluid flow from the
formation into the casing and the lower end of the tubing string is
generally open to provide entry for the fluid in the tubing.
[0002] In many instances artificial lift may be required in order
to raise the produced fluids to the surface. One type of artificial
lift device commonly used is a barrel pump driven from the surface
by a pumpjack connected to the barrel pump by a sucker rod
string.
[0003] A barrel pump is a relatively simple device that has an
outer tubular or barrel that is secured to the casing at a location
where at least the inlet usually the lower end of the barrel will
remain submerged in the produced fluids that flow from the
formation, through the casing perforations, and into the casing. At
the bottom of the barrel is a one way valve typically a ball in a
cage where gravity will act to seat the ball and seal the barrel
against fluid moving out of the inlet and the cage will trap the
ball to prevent the ball from traveling too far from the seat when
fluid moves into the barrel.
[0004] The barrel pump also has a plunger that is located inside of
the barrel and has a plunger body sealed to the barrel's interior
wall. A polished rod is attached to the plunger body and is of
sufficient length so that the polished rod will extend through the
upper end of the barrel even at the bottom of the plunger's stroke.
The plunger also has a one way valve located at the lower end of
plunger body. The one way valve in the plunger body is similar to
the one way valve at the bottom of the barrel in that the plunger
body valve is typically a ball in a cage where gravity will act to
seat the ball and seal the plunger against fluid moving downward
past the plunger and the cage will trap the ball to prevent the
ball from traveling too far from the seat when fluid moves upwards
past the plunger body.
[0005] In operation the plunger moves downward in barrel. The
downward motion is typically caused by removing the upward force
applied by the pump jack via the sucker rods. The weight of the
sucker rods in addition pushes the plunger body through the fluid
in the barrel. As the plunger body moves through the fluid in the
barrel the one way valve in the bottom of the barrel seats and
seals the barrel to prevent the fluid from moving out of the barrel
while the one way valve in the plunger body moves off of its seat
to allow fluid in the barrel to move past the plunger body as the
plunger body moves toward the bottom of the barrel. Once the
plunger body reaches the bottom of the barrel upwards force is
again applied to the plunger body by the pump jack through the
sucker rods.
[0006] As the plunger is forced upwards in the barrel, gravity as
well as the fluid above the plunger body close the one way valve
preventing the fluid from moving past the plunger body and back
into the barrel. The plunger body, sucker rods, and the pump jack
may then act together to move the fluid upwards through the
production tubular. In many instances the force acting on the
plunger through the sucker rods may exceed 100,000 pounds.
Additionally, as the plunger body moves upwards, the one way valve
in the bottom of the barrel will open to allow fluid from the
casing to enter into the barrel to replace the fluid that is above
the plunger and moving upwards.
[0007] At some point it may become necessary to remove the plunger
or even the entire barrel pump assembly from the well. However,
over the life of the barrel pump the barrel or other portions of
the barrel pump assembly may become sanded in, corroded, or
otherwise difficult to remove from the wellbore. Typically the
sucker rod assembly is not robust enough to transmit the necessary
force without damaging the sucker rod string for later use. In many
instances it may be desirable remove only the sucker rod assembly
simply to adjust and maintain the sucker rod assembly without
removing either the plunger or the entire barrel pump assembly.
Therefore it may be desirable to install a disconnect device in the
sucker rod string. The disconnect device must be able to disconnect
the sucker rod string at the desired location but must also be able
to be reconnected as desired by the operator. Usually, the
disconnect device is installed in the sucker rod string as close to
the polished rod as possible. Unfortunately it has become apparent
that the disconnect devices currently used in the industry may be
the weakest part of the sucker rod string thereby becoming the
point in the sucker rod string that is the most likely to fail.
Testing has indicated that the currently used disconnect becomes
weaker over time due to the loading and unloading of the disconnect
of loads that may be in excess of 100,000 pounds several time each
minute for months or even years.
[0008] There exists, therefore, a significant need for an improved
sucker rod disconnect that allows the sucker rod assembly to be
disconnected at a particular point but may then be reconnected
without the disconnect becoming the weakest point in the sucker rod
assembly, and thereby becoming the most likely failure point in the
sucker rod string. The present invention fulfills these needs and
provides further related advantages.
SUMMARY
[0009] The present invention is a disconnect that may be
disconnected from the sucker rod string by rotating the sucker rod
string in a direction that is opposite of the direction that the
threads connecting the sucker rods are cut. Typically sucker rods
are cut with threads that tighten when rotated to the right and
loosen when rotated to the left therefore the current
invention.
[0010] An embodiment for disconnecting a sucker rod may include an
upper section. The upper section has an upper end and a lower end
and the upper end has a first threaded section and the lower end
has a second threaded section threaded in the opposite direction of
the first threaded section. A lower section has an upper end and a
lower end and the lower end has a third threaded section and the
upper end has a fourth threaded section threaded in the opposite
direction of the third threaded section. The second threaded
section and the fourth threaded section cooperate to join the upper
section and the lower section.
[0011] The apparatus for disconnecting a sucker rod may include a
second threaded that has left hand threads and a fourth threaded
section with left hand threads. The first threaded section may be a
box connector and the third threaded section may be a box
connector. The upper section may be a rod and the lower section may
be a rod. The upper section may be a tube and the lower section may
be a tube. The upper section and the lower section may each be a
rod or a tube.
[0012] Another embodiment for reconnecting a sucker rod may have a
lower section with an interior, an upper end, and a lower end. The
interior of the lower end has a first threaded section and interior
of the upper end has a second threaded section that is threaded in
the opposite direction of the first threaded section. An upper
section with an interior, an upper end, and a lower end. The
interior of the upper end has a third threaded section. A
reinforcing member with an exterior, an upper end, and a lower end,
and a recess. The exterior of the upper end of the reinforcing
member is attached to the interior of the lower end of the upper
section and the exterior of the lower end of the reinforcing member
has a bias device. The recess may be located between the lower end
of the upper section and the bias device. At least one retaining
collet having an interior, an exterior, an upper end, and a lower
end. The exterior lower end has a fourth threaded section that
cooperates with the threads of the second threaded section. The
interior of the lower end has a shoulder that cooperates with the
bias device. The retaining collet is located in the recess such
that the bias device provides force in the radial outward direction
against the shoulder.
[0013] The apparatus for reconnecting a sucker rod may include a
bias device that may be a ramp. The second threaded section may
have left hand threads. The second threaded section may have right
hand threads. The second threaded section may have threads that
have a lower surface that extends from the radially inward lower
end of each thread radially outward to radially outwards upper end
of each thread.
[0014] Another embodiment of the invention may include a method of
reconnecting a sucker rod string comprising attaching a disconnect
assembly to a sucker rod string, rotating the sucker rod string in
a first direction, removing the upper portion of the disconnect
assembly from the wellbore, attaching a reconnect assembly to the
sucker rod string, running the reconnect assembly into a wellbore,
stabbing the reconnect assembly into a lower end of the disconnect
assembly, and locking the reconnect assembly to the lower end of
the disconnect assembly.
[0015] The method of reconnecting a sucker rod may include rotating
the sucker rod string in a first direction that is to the left. In
some cases the method of reconnecting a sucker rod may include
rotating the sucker rod string in a first direction that is to the
right. The reconnect assembly may have an external threaded surface
where the threads have a lower surface that extends from the
radially inward lower end of each thread radially outward to
radially outwards upper end of each thread. The reconnect assembly
may be locked to the lower end of the disconnect by a bias device
and a retaining collet shoulder.
[0016] As used herein the terms "tightening" means in a right hand
direction as the nut progresses onto a bolt or threaded section and
"reverse" means in a left hand direction, typically as a nut is
removed from a bolt or threaded section. Lower or downward means
towards the bottom of the while upper or upwards means towards the
surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 depicts a wellbore with a barrel pump, a sucker rod
string, a disconnect, and a surface drive.
[0018] FIG. 2 depicts a detailed view of the lower end of the
wellbore, barrel pump, disconnect, and sucker rod string of FIG.
1.
[0019] FIG. 3 depicts a prior art sucker rod disconnect.
[0020] FIG. 4 depicts an embodiment of a sucker rod disconnect.
[0021] FIG. 5 depicts an embodiment of a sucker rod reconnect.
[0022] FIG. 6 depicts a cross-section of the sucker disconnect of
FIG. 5.
DETAILED DESCRIPTION OF EMBODIMENT(S)
[0023] The description that follows includes exemplary apparatus,
methods, techniques, and instruction sequences that embody
techniques of the inventive subject matter. However, it is
understood that the described embodiments may be practiced without
these specific details.
[0024] FIG. 1 depicts a wellbore 10 with cement in the annular area
14 between the casing 12 and the wellbore 10 to secure the casing
12 in place. The casing 12 has perforations 28 to allow fluid from
the formation 30 flow into the interior of the casing 12. On the
surface 16 a reciprocating pumpjack 18 is connected to the sucker
rod string 20. The sucker rod string 20 is attached to disconnect
22 that is, in turn, connected to polished rod 24. Polished rod 24
is attached to the plunger body 26. A barrel pump 32 is placed in
the casing 12 and secured by anchors 38 so that the barrel 34 inlet
36 is immersed in the formation fluid.
[0025] As the pumpjack 18 pulls the plunger body 26 upward in the
barrel 34 the one way valve 42 seals the plunger body 26 so that
fluid may not move through the plunger body 26 as the plunger body
26 is moved upwards causing the fluid to move out of the barrel 34
via the barrel exit ports 46 thereby lifting the entire column of
fluid towards the surface via production tubing 44. Additionally,
as the plunger body 26 moves upwards in the barrel 34 the one way
valve 40 at the inlet 36 to the barrel 34 opens to allow fluid to
move into the barrel 34 to replace the fluid that is moving towards
the surface 16 above the plunger body 26.
[0026] Once the pumpjack 18 reaches the top of its stroke the
pumpjack 18 reverses the force exerted on the sucker rod string 20
allowing the sucker rod string 20 to move downwards, ultimately
allowing the plunger body 26 to move downwards. As the plunger body
26 moves downwards the one way valve 40 at the bottom of barrel 34
closes to prevent the fluid in the barrel 34 form flowing back into
the casing 12. At the same time the one way valve 42 opens to allow
the fluid in the barrel 34 to flow past the plunger body 26.
[0027] FIG. 2 depicts a close up view of the lower well 10, lower
casing 12, production tubing 44, formation 30, barrel pump 32,
disconnect 22, and lower sucker rod 20.
[0028] FIG. 3 depicts a prior art sucker rod disconnect 50. The
sucker rod disconnect 50 has a body 52. At the upper end of the
body 52 is a pin connector 54 that may thread into the sucker rod
string. Within the housing body 52 is a spring 56 and a spring
guide 58. The sucker rod disconnect 50 also has a key 60. At the
lower end of the key 60 is a box connector 62 that may be threaded
onto either the sucker rod string or the polished rod. The key 60
is depicted in the locked position such that the housing shoulder
64 cooperates with the key shoulder 66 to transmit the tensile
forces exerted by the pump jack on the up stroke that would
otherwise pull the key 60 from the housing 52. Key shoulder 68
cooperates with housing shoulder 70 to transmit to the polished rod
and ultimately the plunger body, any compressive forces that be
exerted through the disconnect 50.
[0029] The key 60 is typically inserted into the key slot 72 where
the key 60 acts upon the spring guide 58 to compress the spring 56.
The key 60 is then rotated, typically about 90 degrees, to place
the key 60 in the locked position. The spring guide 58 and the
spring 56 then act upon the key 60 to prevent the key from
returning to the unlocked position until the operator desires to
disconnect the sucker rod string at the location of the disconnect.
The key 60 allows the operator to disconnect the sucker rod string
or to reconnect the sucker rod string, as desired.
[0030] FIG. 4 depicts an embodiment of the present invention. FIG.
3 depicts a sucker rod connector 100 with an upper portion 102 and
a lower portion 104. The upper portion 102 has threads 106 on its
top end to accept a sucker rod pin connector. The upper portion 102
has on its lower end a threaded section 108 where the threads are
cut to tighten in the direction opposite that of the threaded
section 106. For example, typically the threaded section 106 may
have threads cut to tighten when rotated in the right hand
direction usually referred to as right hand threads. In the case
where the threaded section 106 is cut with right hand threads then
the threaded section 108 would be cut with threads that tighten
when rotated in the left hand direction usually referred to as left
hand threads.
[0031] The lower portion 104 has threads 110 on its lower end to
accept a sucker rod pin connector. The lower portion 104 has on its
upper end a threaded section 112 where the threads are cut to
tighten in the direction opposite that of the threaded section 110.
The threaded sections 108 and 112 cooperate so that the upper
portion 102 and the lower portion 104 may be coupled together. The
upper portion 102 and the lower portion 104 are coupled together
and then sufficient torque is applied such that the upper portion
102 and the lower portion 104 will not become uncoupled until the
operator desires to disconnect the sucker rod string. In some
instances it may be desirable to add a shear device 114 such as a
shear pin or a shear screw to prevent rotation of the disconnect
100 until the operator desires to disconnect the sucker rod
string.
[0032] FIG. 5 depicts an embodiment of the present invention that
allows the operator to reconnect the sucker rod string to the lower
portion 104 after the upper portion 102 and the lower portion 104
have been disconnected in the casing.
[0033] FIG. 5 depicts the lower portion 104 of the disconnect 100
after the upper portion 102 of the disconnect 110 has been removed.
The lower portion 104 has threads 110 on its lower end to accept a
sucker rod pin connector. The lower portion 104 has on its upper
end a threaded section 112 where the threads are cut to tighten in
the direction opposite that of the threaded section 110.
[0034] The reconnect tool 200 has threads 202 on its top end to
accept a sucker rod pin connector. A collet 216 is at least
partially circumferential about the reconnect tool 200. The
exterior face of the collet 216 has a threaded section 218 that are
cut to tighten in the direction opposite that of the threaded
section 110 but will cooperate with the threads 112 to tighten when
rotated in the appropriate direction. Typically the threaded
section 118 may be modified so that an angled surface 219 on the
lower portion of each thread is presented to the threaded section
112 as the reconnect tool 200 is lowered into place. The angled
surface 219 is a lower surface of the threads 218 that extend from
the radially inward lower end of each thread radially outward to
radially outwards upper end of each thread. Typically the modified
threaded section 219 is referred to as a modified, left hand,
square thread for an anchor latch. The angled section 219 of each
thread of the threaded section 218 allows the reconnect tool 200 to
be stabbed in to place with regard to the lower portion 104 but
with a square thread on the upper side of each thread the reconnect
tool may not be simply pulled straight out.
[0035] Typically, the collet 216 of the reconnect tool 200 is
located in a recess created by upper surface 243 and sidewall 244
of the top subassembly 224 and sidewall 242 of the reinforcing
member 220. Typically the collet 216 is held place or locked by
bearing surface 230 of reinforcing member 220 that is biased to
exert pressure against the bearing surface 232 of the collet 216.
The collet 216 is not held rigidly in the recess until it is locked
in place by the bearing surface 232 to allow the collet 216 to move
slightly as it stabs into the lower portion 104.
[0036] In order to prevent movement between the lower portion 104
and the top subassembly 224 the operator my rotate the sucker rod
string some amount to tighten the cooperating threads 112 and 218.
To allow the threads 112 and 218 to transmit any tension through
the top subassembly 224 to the lower portion 104 the reinforcing
member 220. Bearing surface 230 acts against the bearing surface
232 thereby transmitting the tensile force to the collet 216 and
through the threads 218 and 112 to the lower portion 104.
[0037] Collet 216 is retained by reinforcing member 220 in order to
prevent the collet 216 from moving inward toward the center of the
reconnect tool 200 when tensile force is exerted through the sucker
rod string by the pumpjack. The reinforcing member 220 is attached
to the top subassembly 224 by threads, although any means of
attaching the reinforcing member 220 to the top subassembly 224
could be used, such as welding, pins, or constructing the
reinforcing member 220 as a part of the top subassembly 224.
Additionally,
[0038] The top subassembly 224 has a shoulder 226 through which it
may exert a downward or compressive force against the bearing
surface 228 of the lower portion 104.
[0039] FIG. 6 shows a top down view of the reconnect tool 200 and
the lower portion 104 at cross-section A-A in FIG. 4. The
reinforcing member 220 and collet 216 are surrounded by the lower
portion 104 and interface through the threads 112, of the lower
portion 104, and the threads 218 of the collet 216. The collet 216
may be divided into sections such as 216A, 216B, 216C, and 216D but
it may have pockets or recesses. To transmit any rotational forces
to the collet 216 the reinforcing section 220 may have protrusions
250 such as 250A, 250B, 250C, and 250D that extend into the pockets
or recesses of the collet 216 or between the collet sections 216A,
216B, 216C, and 216D. The protrusions such as 250A, 250B, 250C, and
250D may then act on the collet sections 216A, 216B, 216C, and 216D
when any rotational force is applied to the sucker rod string.
While four sets of protrusions and collet sections are shown it
should be understood that any number may be used to transmit the
torque.
[0040] While the embodiments are described with reference to
various implementations and exploitations, it will be understood
that these embodiments are illustrative and that the scope of the
inventive subject matter is not limited to them. Many variations,
modifications, additions and improvements are possible.
[0041] Plural instances may be provided for components, operations
or structures described herein as a single instance. In general,
structures and functionality presented as separate components in
the exemplary configurations may be implemented as a combined
structure or component. Similarly, structures and functionality
presented as a single component may be implemented as separate
components. These and other variations, modifications, additions,
and improvements may fall within the scope of the inventive subject
matter.
* * * * *