U.S. patent application number 15/004537 was filed with the patent office on 2016-07-28 for rod suspension system for integrated wellhead.
The applicant listed for this patent is Weatherford Technology Holdings, LLC. Invention is credited to Kyle C. Brosch, Clark E. Robison, Benson Thomas, James S. Trapani.
Application Number | 20160215575 15/004537 |
Document ID | / |
Family ID | 55299785 |
Filed Date | 2016-07-28 |
United States Patent
Application |
20160215575 |
Kind Code |
A1 |
Robison; Clark E. ; et
al. |
July 28, 2016 |
Rod Suspension System for Integrated Wellhead
Abstract
An artificial lift system for a well having a wellhead
reciprocates a rod string with an uphole pump unit at the wellhead
to operate a downhole pump unit in the well and lift fluid in the
well. A rod segment coupled to the rod string at the wellhead has
first opposing surfaces facing in first opposing directions.
Opposing catchers are movable laterally relative to the rod segment
at the wellhead. Each of the catchers has a face with second
opposing surfaces facing in second opposing directions opposite to
the first opposing directions. The catchers moved in a first
condition have the second opposing surfaces disengaged from the
first opposing surfaces of the rod segment, but the catchers moved
in a second condition have the second opposing surfaces engaged
with the segment's first opposing surfaces to hold the rod string
in place.
Inventors: |
Robison; Clark E.; (Tomball,
TX) ; Trapani; James S.; (Houston, TX) ;
Thomas; Benson; (Pearland, TX) ; Brosch; Kyle C.;
(Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Weatherford Technology Holdings, LLC |
Houston |
TX |
US |
|
|
Family ID: |
55299785 |
Appl. No.: |
15/004537 |
Filed: |
January 22, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62106569 |
Jan 22, 2015 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 33/062 20130101;
E21B 17/1071 20130101; E21B 33/03 20130101; E21B 43/121 20130101;
E21B 19/10 20130101 |
International
Class: |
E21B 19/10 20060101
E21B019/10; E21B 43/12 20060101 E21B043/12; E21B 33/03 20060101
E21B033/03 |
Claims
1. An apparatus for use at a wellhead of a well having a downhole
unit operated with a rod string extending downhole from an uphole
unit at the wellhead, the apparatus comprising: a rod segment
coupling to the rod string and having first opposing surfaces
facing in first opposing directions, the rod segment movable in
relation to the wellhead; and opposing catchers movable laterally
at the wellhead relative to the rod segment, the opposing catchers
each having a face with second opposing surfaces facing in second
opposing directions opposite to the first opposing directions, the
opposing catchers moved in a first condition at the wellhead having
the second opposing surfaces of the faces disengaged from the first
opposing surfaces of the rod segment, the opposing catchers moved
in a second condition at the wellhead having the second opposing
surfaces of the faces engaged with the first opposing surfaces of
the rod segment.
2. The apparatus of claim 1, wherein the first opposing surfaces
comprise first inward surfaces facing inward toward one another and
forming a plurality of troughs defined circumferentially about the
rod segment.
3. The apparatus of claim 2, wherein the second opposing surfaces
comprise second outward surfaces facing outward away from one
another and forming a plurality of teeth projecting from the face
for mating in the troughs of the rod segment.
4. The apparatus of claim 1, wherein the first opposing surfaces
comprise first outer portions of a concavity defined
circumferentially about the rod segment.
5. The apparatus of claim 4, wherein the second opposing surfaces
comprise second outer portions of a convexity extending from the
face and positionable adjacent the concavity of the rod
segment.
6. The apparatus of claim 1, wherein the rod segment comprises a
first end coupleable to a first section of the rod string and
comprises a second end coupleable to a second section of the rod
string.
7. The apparatus of claim 1, further comprising an actuator
coupling to at least one of the opposing catchers and operable to
move the at least one opposing catcher between the first and second
conditions.
8. The apparatus of claim 7, wherein the actuator comprises an arm
coupling to the at least one opposing catcher and movable laterally
relative to the rod segment.
9. The apparatus of claim 8, wherein the at least one opposing
catcher defines a slot, and wherein the arm comprises a key
coupling with the slot.
10. The apparatus of claim 1, wherein the second opposing surfaces
of the face engaged with the first opposing surfaces of the rod
segment restrain movement of the rod segment longitudinally in
opposing directions.
11. The apparatus of claim 1, wherein the opposing catchers in the
second condition restrain movement of the rod segment
laterally.
12. The apparatus of claim 1, further comprising a component
disposed at the wellhead, the component having a throughbore for
passage of the rod segment and having first cross-openings for the
opposing catchers communicating with the throughbore.
13. The apparatus of claim 12, wherein the rod segment comprises a
polished section.
14. The apparatus of claim 13, wherein the component comprises
opposing rams movable laterally in second cross-openings of the
component relative to the rod segment, the opposing rams movable
between sealed and unsealed conditions with the polished section of
the rod segment.
15. The apparatus of claim 12, wherein the component comprises at
least one flange disposed at one end thereof and coupleable with a
portion of the wellhead.
16. An artificial lift system for a well having a wellhead, the
system comprising: a rod string; an uphole unit at the wellhead
operable to move the rod string in the well; a downhole unit in the
well operable to lift fluid in the well in response to the movement
of the rod string; and a rod segment coupled to the rod string at
the wellhead and having first opposing surfaces facing in first
opposing directions; and opposing catchers movable laterally
relative to the rod segment at the wellhead, the opposing catchers
each having a face with second opposing surfaces facing in second
opposing directions opposite to the first opposing directions, the
opposing catchers moved in a first condition at the wellhead having
the second opposing surfaces of the faces disengaged from the first
opposing surfaces of the rod segment, the opposing catchers moved
in a second condition at the wellhead having the second opposing
surfaces of the faces engaged with the first opposing surfaces of
the rod segment.
17. The system of claim 16, comprising a component disposed at the
wellhead, the component having a throughbore for passage of the rod
segment and having first cross-openings communicating with the
throughbore for the opposing catchers.
18. The system of claim 17, wherein the rod segment comprises a
polished section; and wherein the component comprises rams movable
laterally in a second cross-openings relative to the rod segment,
the rams movable between sealed and unsealed conditions with the
polished section of the rod segment.
19. The system of claim 16, wherein the uphole unit at the wellhead
is operable to reciprocate the rod string longitudinally in the
well; and wherein the downhole unit in the well is operable to lift
fluid in the well in response to the reciprocation of the rod
string.
20. The system of claim 19, wherein the downhole unit comprises a
reciprocating rod pump disposed in the well; and wherein the uphole
unit comprises a pump jack or a hydraulic jack.
21. The system of claim 16, wherein the uphole unit at the wellhead
is operable to rotate the rod string in the well; and wherein the
downhole unit in the well is operable to lift fluid in the well in
response to the rotation of the rod string.
22. The system of claim 21, wherein the downhole unit comprises a
progressive cavity pump having a stator with a rotor rotatable
therein by the rotation of the rod string; and wherein the uphole
unit comprises a rotary drive imparting the rotation to the rod
string.
23. An apparatus for use at a wellhead having a downhole unit
operated with a rod string extending downhole from an uphole unit
at the wellhead, the apparatus comprising: a rod segment coupling
to the rod string and having a downward-facing profile, the rod
segment movable longitudinally relative to the wellhead; and
opposing catchers movable laterally in the wellhead relative to the
rod segment, the catchers each having a forked support with an
upward-facing profile, the catchers moved in a first condition
having the upward-facing profiles disengaged from the
downward-facing profile of the rod segment, the catchers moved in a
second condition having the upward-facing profiles supporting with
the downward-facing profile of the rod segment.
24. The apparatus of claim 23, wherein the forked support of a
first of the opposing catchers when in the second condition fits
under at least a portion of the forked support of a second of the
opposing catchers.
25. An apparatus for use at a wellhead having a downhole unit
operated with a rod string extending downhole from an uphole unit
at the wellhead, the apparatus comprising: a rod segment coupling
to the rod string and having a first downward-facing profile and
first upward-facing profile, the rod segment movable longitudinally
relative to the wellhead; and opposing catchers movable laterally
in the wellhead relative to the rod segment, a first of the
opposing catchers having a first forked support with a second
upward-facing profile, a second of the opposing catchers having a
second forked support with a second downward-facing profile, the
opposing catchers moved in a first condition having the second
profiles disengaged from the first profiles of the rod segment, the
opposing catchers moved in a second condition having the second
profiles engaged with the first profiles of the rod segment.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Prov. Appl. No.
62/106,569, filed 22 Jan. 2015, which is incorporated herein by
reference.
BACKGROUND OF THE DISCLOSURE
[0002] Many hydrocarbon wells are unable to produce at commercially
viable levels without assistance in lifting the formation fluids to
the earth's surface. In some instances, high fluid viscosity
inhibits fluid flow to the surface. More commonly, formation
pressure is inadequate to drive fluids upward in the wellbore. In
the case of deeper wells, extraordinary hydrostatic head acts
downwardly against the formation and inhibits the unassisted flow
of production fluid to the surface.
[0003] A common approach for urging production fluids to the
surface uses a mechanically actuated, positive displacement pump.
Reciprocal movement of a string of sucker rods induces reciprocal
movement of the pump for lifting production fluid to the surface.
For example, a reciprocating rod lift system S of the prior art is
shown in FIG. 1 to produce production fluid from a wellbore B. As
is typical, surface casing C hangs from the surface and has a liner
casing L hung therefrom by a liner hanger H. Production fluid from
the formation F outside cement CT can enter the liner L through
perforations P. To convey the fluid, production tubing T extends
from a wellhead W downhole, and a packer PK seals the annulus
between the production tubing T and the liner L. At the surface,
the wellhead W receives production fluid from the tubing T and
diverts it to a flow line FL.
[0004] The production fluid may not produce naturally reach the
surface so operators use the reciprocating rod lift system S to
lift the fluid. The system S has a surface pumping unit SPU, a rod
string RS, and a downhole pump unit DPU. Any number of surface
pumping units SPU can be used, such as a pump jack shown, hydraulic
unit, or the like. The surface pumping unit SPU reciprocates the
rod string RS, and the reciprocating string RS operates the
downhole pump unit DPU to lift produced fluid up the production
tubing T to the wellhead W. Any number of downhole pump units DPU
can be used, such as the rod pump shown having the barrel and
plunger.
[0005] Whenever service is required on the reciprocating rod lift
system S, some means of suspending the rod string RS at the
wellhead W is required to facilitate any service operations that
are required. Conventional wellheads W have seal rams to seal
around the polished rod sections of the rod string RS, but there
generally is not a way to suspend the rod string RS. This problem
has been addressed by the so-called rod lock wellhead system
described in U.S. Pat. No. 6,223,819 to Double-E Inc.
[0006] For example, FIG. 2 shows the prior art lock assembly 23
disclosed in U.S. Pat. No. 6,223,819. The lock assembly 23 is used
on a wellhead 10, which has upper and lower bodies 11 and 12
secured together by nut-bolt assemblies 13. A bore 15 extends
through the bodies 11, 12 for a sucker rod or string 20 to extend
through the wellhead to a downhole pump (not shown).
[0007] The lock assembly 23 is mounted in the upper body 11 for
supporting the rod string 20 and to prevent the rod string 20 from
being accidentally released. The assembly 23 includes a support rod
24, an operator screw 25, and a support sleeve or nut 30. Shown in
a locked or engaged position in FIG. 2, the assembly 23 locks the
rod string 20 out of operation and supports the rod string 20 from
the wellhead.
[0008] As shown in FIGS. 3A-3B, the support rod 24 is a cylindrical
member with a keyway 31 formed in the first or outward end of the
rod for coupling the operator screw 25 with the rod 24. The inward
end of the support rod 24 has an open ended vertical 2-step slot
32. A lower slot portion 32a is sized to fit around the rod string
20 below a coupling flange 33 on the rod string 20, and an upper
larger slot portion 32b serves as a locking slot sized to receive
the coupling flange 33 on the rod string 20 for supporting the rod
string 20.
[0009] The upper slot portion 32b is formed with inward vertical
curved surface portions 32c and with vertical locking flanges 32d,
which are spaced apart laterally to accommodate the diameter of the
rod string 20 below the rod string locking flange 33. The larger
size of the upper slot portion 32b relative to the lower slot
portion 32a provides a support shoulder surface 32e.
[0010] The support rod 24 can be moved laterally to an engaged
position only when the rod string 20 is lifted to an elevation at
which the coupling flange 33 is above the support rod upper slot
portion 32b. When the support rod 24 is moved inwardly by the
operator screw 25 to the engaged position, the rod string 20 may be
lowered with the flange 33 on the rod string 20 moving downwardly
entering the upper slot portion 32b to rest on the shoulder surface
32e. At this position, the curved slot surfaces 32c fit inwardly or
wrap somewhat around the rod flange 33 so that the vertical lock
flanges 32d prevent the support rod 24 from being moved laterally
out of engagement with the rod string 20. The support rod 24 can be
disengaged from the rod string 20 when the rod string 20 is lifted
upwardly to a position at which the coupling flange 33 is not in
the upper slot portion 32b of the support rod 24.
[0011] As illustrated in FIG. 2, the operator screw 25 fits through
and is threadingly engaged with a sleeve 30 so that rotation of the
operator screw 25 in the sleeve 30 moves the support rod 24
inwardly to engage the rod string 20 end outwardly to disengage the
support rod 24 from the rod string 20. The support rod 24 slides
inwardly and outwardly in a lateral cylindrical bore 26 formed in
the upper body 11 of the wellhead.
[0012] When it is necessary to perform services or remove
components, the wellhead 10 can be shut in using other components
(not shown). To then suspend the rod string 20 in the well from the
wellhead 10, the rod string 20 is raised to an elevation at which
the coupling flange 33 is above the intersection of bore 26 in the
upper body 11 with the vertical bore 15 through the body. The
operator screw 25 is rotated to drive the support rod 24 inwardly
to the locked position shown in FIG. 2 at which the inward ends of
the opposite sides of the rod 24 engage the inward end of the blind
bore 26 so that the open inward end of the rod 24 is around the rod
string 20 below the coupling flange 33. At this fully locked
position of the support rod 24, the rod string 20 below the flange
33 is within slot 32 with the lower cylindrical surface portion 32a
of the slot engaging the rod string 20 below the flange 33 limiting
the inward movement of the support rod 24. The rod string 20 is
then lowered with the flange 33 entering the upper slot portion 32b
of the rod 24. The lower edge of the flange 33 engages the support
shoulder 32e of the support rod 24 at the lower end of the upper
slot portion 32b so that the lower end of the flange 33 rests on
the support shoulder 32e thereby suspending the rod string 20 in
the well. With the rod string 20 locked at a suspended position in
the wellhead 10, various procedures can be performed, such as
closing blowout preventer ram assemblies (not shown) and the
like.
[0013] As can be seen, the lock assembly 23 discussed above uses a
support rod 24 with a shoulder 32e to engage under a flange 33 on
the rod string 20. In many reciprocating installations, this form
of engagement as well as others used in the prior art may damage
the sealing surface of the polished rod section, which will
eventually damage the seals in a stuffing box or elsewhere on a
wellhead.
[0014] The subject matter of the present disclosure is directed to
overcoming, or at least reducing the effects of, one or more of the
problems set forth above.
SUMMARY OF THE DISCLOSURE
[0015] According to the present disclosure, an apparatus is used
with a wellhead having a downhole unit operated with a rod string
extending downhole from an uphole unit at the wellhead. The
apparatus comprises a rod segment and opposing catchers. The rod
segment couples to the rod string and has first opposing surfaces
facing in first opposing directions. The rod segment is movable in
the wellhead. For a reciprocating system, the rod segment can be
moved longitudinally in the wellhead as the uphole unit
reciprocates the rod string to operate the downhole unit. For a
rotary system, the rod segment can be rotatable in the wellhead as
the uphole unit rotates the rod string to operate the downhole
unit.
[0016] The opposing catchers are movably laterally in the wellhead
relative to the rod segment. Each of the catchers has a face with
second opposing surfaces facing in second opposing directions
opposite to the first opposing directions. The catchers moved in a
first condition in the wellhead have the second opposing surfaces
of the faces disengaged from the first opposing surfaces of the rod
segment. Alternatively, the catchers moved in a second condition in
the wellhead have the second opposing surfaces of the face engaged
with the first opposing surfaces of the rod segment.
[0017] In use, the second opposing surfaces of the face engaged
with the first opposing surfaces of the rod segment restrain
movement of the rod segment longitudinally in opposing directions.
Likewise, the opposite catches in the engaged condition restrain
movement of the rod segment laterally.
[0018] In one embodiment, the first opposing surfaces can comprise
surfaces facing inward toward one another forming a plurality of
troughs defined circumferentially about the rod segment. As a
corollary, the second opposing surfaces can then comprise surfaces
facing outward away from one another forming a plurality of teeth
projecting from the face for mating in the troughs of the rod
segment.
[0019] In another embodiment, the first opposing surfaces can
comprise outer portions of a concavity defined circumferentially
about the rod segment. To be complimentary, the second opposing
surfaces can then comprise outer portions of a convexity extending
from the face and positionable adjacent the concavity of the rod
segment.
[0020] The rod segment can be separately coupleable to sections of
a rod string. For example, a first end of the rod segment can be
coupleable to a first section of the rod string, while a second end
of the rod segment is coupleable to a second section of the rod
string.
[0021] The apparatus can further comprise an actuator coupling to
one of the catchers and operable to move the catcher between the
engaged and disengaged conditions. For example, the actuator can
comprise an arm coupling to the catcher and movable laterally
relative to the rod segment. In turn, the catcher may define a
slot, and the arm can comprise a key coupling with the slot.
[0022] According to the present disclosure, an apparatus is used
with a wellhead having a downhole unit operated with a rod string
extending downhole from an uphole unit at the wellhead. The
apparatus comprises a component, a rod segment, and opposing
catchers. The component is disposed on the wellhead. The component
has an axial bore for passage of the rod string and has first
cross-openings communicating with the axial bore. As before, the
rod segment couples to the rod string and has first opposing
surfaces facing inward toward one another.
[0023] Again, the rod segment is movable in the axial bore of the
component. For a reciprocating system, for example, the rod segment
can be moved longitudinally in the component as the uphole unit
reciprocates the rod string to operate the downhole unit. For a
rotary system, the rod segment can be rotatable in the component as
the uphole unit rotates the rod string to operate the downhole
unit.
[0024] The opposing catchers are movable laterally in the first
cross-openings of the component relative to the rod segment. As
before, each of the catchers has a face with second opposing
surface facing outward from one another. The catchers moved in a
first condition in the component have the second opposing surfaces
disengaged from the first opposing surfaces of the rod segment.
Alternatively, the catchers moved in a second condition in the
component have the second opposing surfaces engaged with the first
opposing surfaces of the rod segment.
[0025] The rod segment can comprise a polished section. The
component can have second cross-openings communicating with the
axial bore. In this instance, the apparatus can comprise rams
movably laterally in the second cross-openings relative to the rod
segment. The rams movable between engaged and disengaged conditions
with the polished section of the rod segment. For its part, the
component can comprise at least one flange disposed at one end
thereof that is coupleable with a portion of the wellhead.
[0026] According to the present disclosure, an apparatus is used
with a wellhead having a downhole unit operated with a rod string
extending downhole from an uphole unit at the wellhead. The
apparatus comprises a rod segment and opposing catchers. The rod
segment couples to the rod string and has a first, downward-facing
profile. The rod segment is movable axially in the wellhead.
[0027] The opposing catchers are movable laterally in the wellhead
relative to the rod segment. A first of the catchers has a first
forked support with a second, upward facing profile. The catchers
moved in a first condition in the component has the second profile
disengaged from the first profile of the rod segment.
Alternatively, the catchers moved in a second condition in the
component have the second profile engaged with the first profile of
the rod segment.
[0028] A second of the opposing catchers can comprise a second
forked support fitting under at least a portion of the first forked
support when in the second condition. Alternatively, the rod
segment can comprise a third, upward-facing profile. A second of
the opposing catchers can comprise a second forked support with a
fourth, downward facing profile for engagement with the third
profile.
[0029] According to the present disclosure, an artificial lift
system for a well comprises an uphole pump unit, a downhole pump
unit, and an apparatus. The uphole pump unit at the well is
operable to reciprocate a rod string in the well, and the downhole
pump unit in the well is operable to lift fluid in the well in
response to the reciprocation of the rod string. The apparatus can
be similar to that disclosed above and can be disposed between the
uphole and downhole pump units.
[0030] According to the present disclosure, methods are used with a
wellhead having a downhole unit operated with a rod string
extending downhole from an uphole unit at the wellhead. The methods
include steps for engaging a rod segment with opposing catchers and
retaining movement of the rod segment in the wellhead.
[0031] The foregoing summary is not intended to summarize each
potential embodiment or every aspect of the present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 illustrates a reciprocating rod lift system as
background to the present disclosure.
[0033] FIG. 2 illustrates a portion of a wellhead having a lock
assembly according to the prior art for supporting a rod
string.
[0034] FIGS. 3A-3B illustrate a top view and a side cross-sectional
view of a support rod for the lock assembly in FIG. 2.
[0035] FIGS. 4A-4B illustrate cross-sectional views of a wellhead
component, revealing a first rod suspension system according to the
present disclosure in disengaged and engaged conditions.
[0036] FIG. 5 illustrates a detailed view of the catchers and the
rod segment of the first rod suspension system.
[0037] FIGS. 6A-6B illustrate cross-sectional views of a wellhead
component, revealing a second rod suspension system according to
the present disclosure in disengaged and engaged conditions.
[0038] FIGS. 7A-7B illustrate side and end views of the rod segment
for the second rod suspension system of the present disclosure.
[0039] FIG. 8 illustrates a side view of the rod segment and the
opposing rod catchers in an engaged condition.
[0040] FIGS. 9A-9D illustrate perspective, cross-section, top, and
back views of the rod catcher for the second rod suspension
system.
[0041] FIGS. 10A-10B illustrate cross-sectional views of a wellhead
component, revealing a third rod suspension system according to the
present disclosure in disengaged and engaged conditions.
[0042] FIGS. 11A-11B illustrate a forked catcher for the third rod
suspension system in top and front views.
[0043] FIG. 11C illustrates a side view of the wellhead component
with a cross-passage for the forked catcher.
[0044] FIGS. 12A-12B illustrate cross-sectional views of a wellhead
component, revealing a fourth rod suspension system according to
the present disclosure in disengaged and engaged conditions.
[0045] FIG. 13 schematically illustrates a reciprocating pump
system at a wellhead having a rod suspension system according to
the present disclosure.
[0046] FIG. 14 schematically illustrates a rotating pump system at
a wellhead having a rod suspension system according to the present
disclosure.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0047] FIGS. 4A-4B illustrate cross-sectional views of a wellhead
component 50, revealing a first rod suspension system 56A according
to the present disclosure in disengaged and engaged conditions.
Although not shown, the wellhead component 50 can be used as part
of a wellhead having gate valves, tubing spools, casing hangers,
etc. Additionally, any uphole unit, such as a pump jack, a
hydraulic assembly, a rotary drive, or the like can sit on the
wellhead component or elsewhere on the wellhead. Additionally, any
downhole unit (not shown), such as a reciprocating plunger pump, a
progressive cavity pump, or other downhole pump, can be disposed
downhole in a borehole from the wellhead component 50. The uphole
unit can operate the downhole unit using a rod string RS extending
downhole from the wellhead, similar to a reciprocating rod lift
system known in the art and described previously or similar to a
rotary pump system known in the art.
[0048] The wellhead component 50 has an axial throughbore 52 for
passage of the rod string RS, fluid, etc. First cross-openings 54a
communicate with the bore 52 toward the uphole flange 51a of the
component 50, and second cross-openings 54b can also be provided
and can communicate with the bore 52 toward the downhole flange Sib
of the component 50.
[0049] The rod suspension system 56A includes a rod segment 60 and
opposing catchers 70. The rod segment 60 couples to the rod string
RS and can move longitudinally in the bore 52 of the wellhead
component 50. For example, the rod segment 60 can be a pony rod
placed at the top end of the rod string RS and beneath a polished
rod of a surface pumping unit. The rod segment 60 includes a
profiled section 62a and can have a polished section 62b. The rod
segment 60 has a set length to insure the placement of the profile
section 62a is always in close proximity to the rod catchers
70.
[0050] The first cross-openings 54a hold the opposing catchers 70,
while the second cross-openings 54b can hold sealing rams 90. The
catchers 70 can move laterally in the first cross-openings 54a of
the component 50 relative to the rod segment 60. For example, a
ram-type system having actuators (not shown) can be operated to
engage the catchers 70 with the rod segment 60. The rams 90 can
also move laterally in the second cross-openings 54b of the
component 50 relative to the rod segment 60 using a ram-type system
having actuators (not shown).
[0051] As shown in FIG. 4A, the catchers 70 moved in a first
condition (away from one another) in the wellhead component 50 are
disengaged from the rod segment 60. As shown in FIG. 4B, however,
the catchers 70 moved in a second condition (toward one another) in
the wellhead component 50 can engage the rod segment 60 at the
profiled section 62a. When the weight of the rod string RS is
slacked, the catchers 70 will then support all of the weight to
suspend the rod string RS connected to the segment 60 so
maintenance and other operations can be performed.
[0052] As shown in FIG. 4A, the catchers 70 are moved away from one
another in the disengaged condition, which allows the rod segment
60 to pass longitudinally through the bore 52 of the wellhead
component 50, such as when reciprocating during operation. As then
shown in FIG. 4B, the catchers 70 can be moved toward one another
to engage their faces 72 against the profiled section 62b of the
rod segment 60 to hold the rod string at the wellhead component 50
for maintenance or the like.
[0053] At least one or both catcher 70 can be moved by an actuator
80a (only one shown) that couples to the catcher 70 and is operable
to move the catcher 70 between the engaged and disengaged
conditions. The actuator 80a has an arm 82 coupling to the catcher
70 and movable laterally relative to the rod segment 60. In
particular, a key 83 on the arm 82 can engage in a slot 73 in the
back of the catcher 70. The arm can be moved in any conventional
manner, such as screwing in or out.
[0054] In addition to the first cross-openings 54a for the catchers
70, the wellhead component 50 can have the second cross-openings
54b communicating with the bore 50. Rams 90 can be movable
laterally in these second cross-openings 54b of the component 50
relative to the rod segment 60. As shown in FIG. 4B, the rams 90
can be positioned below the catchers 70 and moved to engage their
sealing faces 92 against the polished section 62b of the rod
segment 60. In this way, the sealing rams 90 can be closed around
the polished section 62b of the segment 60 to seal off fluid
communication in the axial bore 52 and to insure the well pressure
is isolated so the surface pumping unit can then be safely
removed.
[0055] Another set of sealing rams 90 can be used either in another
set of cross-openings in the same component 50 or used in another
component of the wellhead. For example, the other set of rams 90
can be a set of sealing rams positioned above the catcher 70 to
seal around an upper section of the rod segment 60 or around a
polished rod of the rod string RS above the segment 60.
Alternatively, the other set of rams 90 can be a set of blind rams
positioned in a lowermost position away from the catchers 70, which
can be in the upper-most position in the sequence rams. These and
other configurations are possible and may have various benefits for
operations.
[0056] The rams 90 can have faces 92 of known design, such as
having an arrangement of rubber and steel for sealing. Overall
during use, the sealing rams 90 can seal around a portion of the
rod string RS in the bore 52, can seal around the polished section
62b of the segment 60 when supported by the catchers 70, or can
close off against one another for shutting the bore 52 in the
absence of a rod string.
[0057] Further details of the rod suspension system 56A are shown
in FIG. 5, which illustrates a detailed view of the rod segment 60
and the opposing catches 70. The rod segment 60 has a first end 61a
coupleable to a first section of the rod string (not shown).
Similarly, the rod segment 60 has a second end 61b coupleable to a
second section of the rod string. As shown, the first and second
ends 61a-b can be box ends having internal threads to connect to
ends of the rod string directly or with connectors, as the case may
be. In other alternatives, one or both of the ends 61a-b can be pin
ends having external threads. Between the ends 61a-b, the rod
segment 60 has the first, profiled section 62a and the second,
polished section 62b.
[0058] The faces 72 of the catchers 70 have outward opposing
surfaces 74a-b of one or more teeth 75. Complementary to this, the
profiled section 62a of the rod segment 60 has inward opposing
surfaces 64a-b of one or more troughs 65. In the current
embodiment, the first opposing surfaces 64a-b on the rod segment 60
form a plurality of the troughs 65 defined circumferentially about
the rod segment 60, and the second opposing surfaces 74a-b on the
catchers 70 form a plurality of the teeth 75 projecting from the
face 72.
[0059] As can be seen, the teeth 75 are configured to mate in the
troughs 65 of the rod segment 60. In particular, the catchers 70
moved toward one another around the profiled section 62a of the rod
segment 60 engage their outward opposing surfaces 74a-b against the
inward opposing surfaces 64a-b of the rod segment 60. This retrains
movement of the rod segment 60 axially in opposing directions when
supported by the catchers 70 in the component's bore 52, as
discussed previously. In other words, the engagement of the catches
70 prevent the rod segment 60 from moving axially up or down in the
bore 52. Moreover, the opposing catches 70 also retain the rod
segment 60 laterally.
[0060] In the above embodiment, the first and second opposing
surfaces 64a-b, 74a-b include mating troughs 65 and teeth 75 for
axially restraining the rod segment 60. Other opposing surfaces can
be used. For example, rather than having multiple sets of opposing
surfaces 64a-b along the profiled section 62a, the rod segment 60
can have one set of outwardly opposing surfaces 64a-b (i.e., in the
form of one trough 65). By complement, the faces 72 of the catchers
70 can have one set of inward opposing surfaces 74a-b (i.e., in the
form of one tooth 75). These surfaces 64a-b, 74a-b can be
rectilinear (i.e., square, trapezoidal, etc.) as shown or can have
other shapes.
[0061] Another embodiment of a rod suspension system 56B shown with
reference to FIGS. 6A to 8 has monolithic faces with opposing
surfaces for the rod segment 60 and the catchers 70. More
particularly, FIGS. 6A-6B illustrates cross-sectional views of a
wellhead component 50, revealing the second rod suspension system
56B according to the present disclosure in disengaged and engaged
conditions. Similar reference numbers are used for like components
to other embodiments disclosed herein.
[0062] The rod segment 60 has a profiled section 62a with a
monolithic face, and the opposing catchers 70 are similarly
configured with opposing surfaces having complementary monolithic
faces 72. In particular, FIGS. 7A-7B illustrate side and end views
of the rod segment 60 for this second rod suspension system of the
present disclosure. Again, the rod segment 60 has ends 61a-b
coupleable to sections of the rod string (not shown). The profiled
section 62a of the rod segment 60 has inwardly opposing surfaces
67a-b facing toward one another. The surfaces 67a-b are defined by
the outer portions of a concavity 66 formed circumferentially about
the rod segment 60.
[0063] By contrast, FIGS. 9A-9D illustrate perspective,
cross-section, top, and back views of a rod catcher 70 for the
second rod suspension system. Complimentary to the surfaces 67a-b
of the rod segment 60, the face 72 of the catcher 70 has a
convexity 76 extending therefrom and positionable adjacent the
concavity 66 of the rod segment 60 for mating therewith. At its
outer portions, the convexity 76 has outwardly opposing surfaces
77a-b facing away from one another.
[0064] Engagement of the catchers 70 with the profiled section 62a
of the rod segment 60 can follow in a similar manner as described
previously. For instance, FIG. 6A illustrates a side view of the
rod segment 60 and opposing rod catchers 70 in a disengaged
condition, and FIG. 6B as well as FIG. 8 illustrate side views of
the rod segment 60 and opposing rod catchers 70 in an engaged
condition.
[0065] As best shown in the detail of FIG. 8, the faces 72 of the
catchers 70 have the outward opposing surfaces 77a-b of the
convexity 76. Complementary to this, the profiled section 62a of
the rod segment 60 has the inward opposing surfaces 67a-b of the
concavity 66. The catchers 70 moved toward one another around the
profiled section 62a of the rod segment 60 engage their outward
opposing surfaces 77a-b against the inward opposing surfaces 67a-b
of the rod segment 60. This retrains movement of the rod segment 60
longitudinally in opposing directions as well as laterally when
supported by the catchers 70 in the component's bore 52, as
discussed previously.
[0066] During operation as shown in FIG. 6A, for example, the
catchers 70 are moved away from one another in a disengaged
condition, which allows the rod segment 60 to pass longitudinally
through the axial bore 52 of the wellhead component 50. As then
shown in FIG. 6B, the catchers 70 can be moved toward one another
to engage their faces 72 against the profiled section 62b of the
rod segment 60 to hold the rod segment 60 and coupled rod string RS
at the wellhead component 50.
[0067] As before, one or both of catchers 70 can be moved by an
actuator 80a (only one shown) that couples to the catcher 70 and is
operable to move the catcher 70 between the engaged and disengaged
conditions. The actuator 80a has an arm 82 coupling to the catcher
70 and movable laterally relative to the rod segment 60. In
particular, a key 83 on the arm 82 can engage in a slot 73 in the
back of the catcher 70.
[0068] In addition to the first cross-openings 54a for the catchers
70, the wellhead component 50 can have the second cross-openings
54b communicating with the bore 50. Rams 90 can be movable
laterally in these second cross-openings 54b of the component 50
relative to the rod segment 60. As shown in FIG. 6B, the rams 90
can be moved to engage their sealing faces 92 against the polished
section 62b of the rod segment 60 to seal off fluid communication
in the axial bore 60.
[0069] FIGS. 10A-10B illustrate cross-sectional views of a wellhead
component 50, revealing a third rod suspension system 56C according
to the present disclosure in disengaged and engaged conditions.
Similar components to other embodiments are given like reference
numbers and are not described again.
[0070] In this system 56C, a first catcher 70a has a forked support
75a for supporting a profile 65a on the rod segment 60, while a
second catcher 70b opposing the first catcher 70a has a forked
support or shelf 75b for also supporting the profile 65a on the rod
segment 60. Both of the supports 75a-b can engage at least a
portion of the profile 65a. As particularly shown herein, the
second catcher's support 75b acts as a shelf and fits under the
forked support 75a on the first catcher 70a.
[0071] In this way, with the catchers 70a-b retracted in the
disengaged condition shown in FIG. 10A, the rod segment 60 can pass
through the component's bore 52. When the catchers 70a-b are
extended to the engaged condition shown in FIG. 10B, the forked
support 75a of the first catcher 70a can support the rod segment 60
and attached rod string RS by engaging the profile 65a. The forked
shelf 75b of the second catcher 70b can in turn support the first
catcher's forked support 75a. (Similar to other embodiments, the
rod segment 60 can have a polished section 65c for engagement by
the rams 90.)
[0072] For reference, FIGS. 11A-11B illustrate an embodiment of the
first forked catcher 70a for the disclosed rod suspension system in
top and front views. The forked support 75a preferably has an
angled surface or shoulder 77 that can match the profile (65a) of
the rod segment (60). For its part, the second forked catcher 70b
can have orthogonal shoulders for its shelf to rest against the
underside of the first catcher's forked support 75a.
[0073] To align and guide the forked catcher 70a, tabs or guides 79
can extend from the sides. As shown in the side view of the
wellhead component 50 in FIG. 11C, the cross-opening 54a for the
first forked catcher (70a) can have side slots 59 in which the tabs
or guides (79) fit.
[0074] In the previous embodiment, the second forked catcher 70b
fits under (at least partially) and supports the first forked
catcher 70a. As an alternative, FIGS. 12A-12B illustrate
cross-sectional views of a wellhead component 50, revealing a
fourth rod suspension system 56D according to the present
disclosure in disengaged and engaged conditions. Similar components
to other embodiments are given like reference numbers and are not
described again.
[0075] In this system 56D, the first catcher 70a has the forked
support 75a for engaging a first profile 65a on the rod segment 60,
while the second catcher 70b opposing the first catcher 70a also
has a forked support 75b for engaging a second, opposite profile
65b on the rod segment 60. In this arrangement, the first forked
support 75a is upward-facing to engage the downward-facing first
profile 65a of the segment 60, and the second forked support 75b is
downward-facing to engage the upward-facing second profile 65b of
the segment 60.
[0076] In this way, with the catchers 70a-b retracted in the
disengaged condition shown in FIG. 12A, the rod segment 60 can pass
through the component's bore 52. When the catchers 70a-b are
extended to the engaged condition shown in FIG. 12B, the forked
supports 75a-b of the first and second catcher 70a-b can engage and
support the rod segment 60 at both of the opposing profiles
65a-b.
[0077] In embodiments of the rod suspension system 56A-D disclosed
herein, the engagement of the faces 72, shoulders 77, and the like
of the catchers 70 with the profiled section 62a, profiles 65a-b,
and the like of the rod segment 60 suspends the rod string RS
without damaging the outside surface of the rod segment 60 or rod
string RS. The inward and outward opposing surfaces 74a-b,
shoulders 77, forked supports 75a-b, and the like of the catchers
70 and the profiled section 62a and profiles 65a-b engage one
another so that the catchers 70 hold the weight of the rod string
RS as well as any downward load and any upward load that may be
applied to the rod string as a function of the well pressure.
[0078] A number of variations can be used for the inward and
outward opposing surfaces. As discussed above in FIGS. 4A-4B and 5,
for example, the surfaces 74a-b can use angled shoulder, although
square shoulders could be used. Additionally, the surfaces 74a-b
can use a series of shoulders facing both directions. In this way,
the one or more surfaces on the catchers 70 can be formed as a pin,
tooth, convexity, etc. of a desired geometry that engages in a
matching hole, trough, concavity, etc. as the one or more surfaces
on the rod segment 60. Other arrangements can be used. In fact, the
catchers 70 can intertwine with the rod segment 60 in any number of
robust structures.
[0079] Although previous arrangements disclosed the opposing
surfaces of the rod segment 60 facing inward toward one another and
disclosed the opposing surfaces of the catchers 70 facing outward
away from one another, an opposite arrangement can be used.
[0080] Although sealing rams 90 have been disclosed for use with
the rod segment 60 as noted above, the engagement of the rod
segment 60 and the catchers 70 may not only support the full weight
of the rod string, but can also help seal off any pressure forces.
Also as an alternative, any sealing rams can be used on other
components of the wellhead to engage another polished section of
the rod string RS so that the wellhead component 50 disclosed
herein can be configured without the second cross-ports 54b and the
rod segment 60 can be configured without the specific polished
section 62b.
[0081] As has been disclosed herein, the wellhead component 50 of
the present disclosure having the catchers 70 (with or without
sealing rams 90) can be used on a Blowout Preventer (BOP) of a
wellhead where multiple sealing rams are used in the BOP. The rod
suspension catchers 70 can be positioned in any sequence in the BOP
relative to the other rams. Preferably, the catchers 70 are either
in a middle position or an upper position in the BOP. Although the
catchers 70 are preferably not in a lowermost position in the BOP,
they could be for a given the implementation.
[0082] For example, FIG. 13 schematically illustrates a pumping
system 100A that can use a rod suspension system 56 according to
the present disclosure. As shown here, the pumping system 100A can
be a reciprocating type of system having a plunger pump for the
downhole unit 108 and having a pump jack 106 or the like as a
surface drive. A wellhead 120 has a Blowout Preventer (BOP) 110, a
stuffing box 130, polished rod 102, and the like along with
catchers 70 and rams 90 of a wellhead component 50 according to the
present disclosure.
[0083] As shown here, the catchers 70 are preferably in an
uppermost position in the BOP 110 because this facilitates the
optimum placement of the rod segment 60 during operations. In
particular, to suspend the rod string 106 during operations, the
rod string 106 can be pulled to its uppermost position by either
the pumping unit 104 (if present) at the surface or by a crane (not
shown). When this is done, the profile 62a on the rod segment 60
will be more readily situated in the correct position between the
opposing catchers 70 in the wellhead component 50.
[0084] With the catchers 70 in the uppermost position, lower rams
90a (in a dual ram configuration) or a middle ram 90b (in a triple
configuration) may include seals configured to seal around a
polished section 62b of the rod segment 60 or around a normal
sucker rod of the rod string 106 and not necessarily a polished rod
102. In the triple BOP configuration, the lowermost rams 90b will
most likely always be a set of blind rams. In this way, should the
rods 102, 106, and/or 60 come apart, the blind rams 90b can be
activated to seal off the well pressure in the BOP 110 without the
need for a rod member to be positioned across the rams 90b.
[0085] Furthermore, the polished rod sections 102 are optimally
placed above the rod segment 60 because the stuffing box 130
normally used to seal against the polished rod 102 is above all of
the rams 90a-b in the BOP 110. This gives the operator the
additional flexibility to suspend the rod string 106, seal off the
well pressure, and then break the connection to the polished rods
102 above the rod segment 60 to replace the stuffing box seals or
the like.
[0086] In one implementation, the rod segment 60 can be about 36-in
in length and about 1.5-in in diameter. With such a length for the
rod segment 60, it is possible for sealing rams 90a configured to
seal around the segment's polished rod section 62b with a 1.5-in
sealing dimension. However, other configurations are possible.
[0087] For instance, the rod segment 60 can be shorter (say 12-in
in length). A changeover thread on the bottom of the segment 60 can
be the size of the sucker rod of the rod string 106 used. In this
case, the sealing rams (e.g., 90a in FIG. 13) in the BOP 110 below
the catchers 70 can be configured to instead seal around a portion
of the sucker rod string 106 with an appropriate sealing
dimension--instead of around the polished section 62b of the rod
segment 60. Being able to seal around the sucker rod string 106 can
be beneficial when operators are changing polished rods 102 out.
The shorter rod segment 60 can be fitted on the lower end of any
length of upper polished rod 102, and a pony rod (not shown) for
spacing of the sucker rod string 106 can extend downhole from the
lower end of the rod segment 60. When the shorter rod segment 60 is
lifted up and held by the catchers 70, the lower sealing rams 90a
on the BOP 110 can be closed on the sucker rod string 106 or the
sucker rod pony used for spacing.
[0088] Because this rod suspension system 56 can include seal rams
90a, the surface pumping unit 104 can be safely removed from the
well to perform whatever service is required. The structure in the
wellhead 120 can be designed with various configurations to
distribute the loads between a key way, in interlocking shoulders
between the catchers 70 and rod segments, or between a dual catcher
system.
[0089] The rod suspension system 56 of the present disclosure can
be used with other uphole and downhole units for other pumping
assemblies, such as rotary pumping assemblies having a progressive
cavity pump or the like. For example, FIG. 14 schematically
illustrates a rotary pump assembly 100B having a rod suspension
system 56 according to the present disclosure.
[0090] This rotary pump assembly 100B is a progressive cavity
pumping system. As such, the assembly 100B includes a progressive
cavity pump 140 as the downhole unit and has a rotary drive 150 as
the uphole unit, which imparts rotation to the progressive cavity
pump 140 via a rod string 106.
[0091] Downhole, the progressive cavity pump 140 installs below the
wellhead 120 at a substantial depth (e.g., about 2000 m) in the
wellbore. Typically, the pump 140 has a single helical-shaped rotor
142 that turns inside a double helical elastomer-lined stator 144.
During operation, the stator 144 attached to production tubing
string 14 remains stationary, and surface drive 150 coupled to
rotor 142 by drive string 106 cause rotor 142 to turn eccentrically
in stator 144. As a result, a series of sealed cavities form
between stator 142 and rotor 144 and progress from the inlet end to
the discharge end of pump 140, which produces a non-pulsating
positive displacement flow.
[0092] At the surface, the surface drive 150 has a drive head 152
mounted above wellhead 120 and has an electric or hydraulic motor
154 coupled to the drive head 152 by a pulley/belt assembly or gear
box 156. The drive head 150 typically includes a stuffing box (not
shown), a clamp 158, and a polished rod 159. The stuffing box is
used to seal the connection of drive head 150 to drive shaft 106,
and the clamp 158 and polished rod 159 are used to transmit the
rotation from the drive head 152 to the drive shaft 106.
[0093] To suspend the rod string 106 for maintenance or the like, a
wellhead component 50 at the wellhead 120 has catchers 70 (and
optionally rams 90). A rod segment 60 of the rod suspension system
56 is connected to the rod string 106 and is disposed in the
wellhead component 50. The catchers 70 and the rams 90 can be
configured respectively to engage the profiled section 62a and the
polished section 62b of the rod segment 60 as before to suspend the
rod string 106.
[0094] For such a rotating system, it may be advantageous to be
able to react to torque in the rod string 106 and prevent rotation
while gripping the rod string 106 to support its weight at the
wellhead 120. Accordingly, the assembly 100B can include components
and features to hold the rod string 106 and prevent it from
rotating due to torque and the like. For example, back spin
retarders, brakes, locking mechanisms, and other components know in
the art can be used to prevent rotation of the rod string 106 when
the rod string 106 is being supported by the rod suspension system
56. Many of these types of components are already used with rotary
drives for rod strings and can be readily incorporated into the rod
suspension system 56 of the present disclosure.
[0095] Moreover, should alignment be achievable between an
orientation of the rod segment 60 and the catchers 70, then
longitudinally arranged slots and profiles between the outside
surface of the rod segment 60 and the inside surfaces of the
catchers 70 can be used to prevent rotation of the rod segment 60
once aligned and engaged by the catchers 70. Although both
longitudinal and rotational support could be provided by the same
catcher 70, separate sets of catchers 70 (one set for longitudinal
support and another set for rotational support) could preferably be
used in the same or separate wellhead component 50.
[0096] The foregoing description of preferred and other embodiments
is not intended to limit or restrict the scope or applicability of
the inventive concepts conceived of by the Applicants. It will be
appreciated with the benefit of the present disclosure that
features described above in accordance with any embodiment or
aspect of the disclosed subject matter can be utilized, either
alone or in combination, with any other described feature, in any
other embodiment or aspect of the disclosed subject matter.
[0097] In exchange for disclosing the inventive concepts contained
herein, the Applicants desire all patent rights afforded by the
appended claims. Therefore, it is intended that the appended claims
include all modifications and alterations to the full extent that
they come within the scope of the following claims or the
equivalents thereof.
* * * * *