U.S. patent application number 12/414053 was filed with the patent office on 2009-10-01 for toggle overshot.
Invention is credited to Harold M. Pardey.
Application Number | 20090242203 12/414053 |
Document ID | / |
Family ID | 41115375 |
Filed Date | 2009-10-01 |
United States Patent
Application |
20090242203 |
Kind Code |
A1 |
Pardey; Harold M. |
October 1, 2009 |
TOGGLE OVERSHOT
Abstract
An overshot includes a sleeve. A coupling member having a
latched state and an unlatched state is disposed at a first end of
the sleeve. A load-responsive toggle mechanism for alternating the
coupling member between the latched state and the unlatched state
is disposed at a second end of the sleeve.
Inventors: |
Pardey; Harold M.;
(Sarasota, FL) |
Correspondence
Address: |
RICHARD A. FAGIN
P.O. BOX 1247
RICHMOND
TX
77406-1247
US
|
Family ID: |
41115375 |
Appl. No.: |
12/414053 |
Filed: |
March 30, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61040981 |
Mar 31, 2008 |
|
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Current U.S.
Class: |
166/301 ;
294/86.27 |
Current CPC
Class: |
E21B 31/18 20130101 |
Class at
Publication: |
166/301 ;
294/86.27 |
International
Class: |
E21B 31/18 20060101
E21B031/18; E21B 31/12 20060101 E21B031/12 |
Claims
1. An overshot, comprising: a sleeve; a coupling member having a
latched state and an unlatched state disposed at a first end of the
sleeve; and a load-responsive toggle mechanism for alternating the
coupling member between the latched state and the unlatched state
disposed at a second end of the sleeve.
2. The overshot of claim 1, wherein the load-responsive mechanism
comprises a first rotator for selectively engaging the coupling and
a second rotator for selectively displacing and rotating the first
rotator.
3. The overshot of claim 2, wherein the load-responsive mechanism
further comprises a weight member for applying a load to the second
rotator that causes the second rotator to selectively displace the
first rotator.
4. The overshot of claim 3, further comprising a first spring
member supporting the second rotator, and wherein the load is
selected to overcome a biasing force of the first spring
member.
5. The overshot of claim 4, further comprising a second spring
member supporting the first rotator, and wherein the load is
selected to overcome a biasing force of second spring member.
6. The overshot of claim 3, wherein the weight member is
selectively movable relative to the sleeve to contact the second
rotator and apply the load to the second rotator.
7. The overshot of claim 3, wherein the second rotator is
selectively movable relative to the sleeve to contact the weight
member and receive the load from the weight member.
8. The overshot of claim 3, further comprising a wireline connector
coupled to the weight member.
9. The overshot of claim 2, wherein the first rotator engages the
coupling when the coupling is in the unlatched state and disengages
from the coupling when the coupling is in the latched state.
10. An overshot, comprising: an outer sleeve; a coupling member
disposed at a first end of the outer sleeve; a first rotator
disposed within the outer sleeve and configured to alternately
engage and disengage from the coupling member, thereby toggling the
coupling member between an unlatched state and a latched state; and
a second rotator disposed within the outer sleeve and configured to
selectively displace and rotate the first rotator in response to an
applied load; and a weight member disposed at a second end of the
outer sleeve for applying a load to the second rotator.
11. The overshot of claim 10, further comprising an inner sleeve
disposed within the outer sleeve.
12. The overshot of claim 11, wherein the inner sleeve comprises a
plurality of keys and the first rotator comprises a plurality of
keys, and wherein the keys on the inner sleeve and the keys on the
first rotator selectively come into contact to rotate the first
rotator relative to the inner sleeve.
13. The overshot of claim 11, further comprising a mechanism for
selectively locking the first rotator to the inner sleeve.
14. The overshot of claim 13, wherein the mechanism comprises a
plurality of key slots on one of the inner sleeve and first rotator
and a plurality of keys on the other of the inner sleeve and first
rotator.
15. The overshot of claim 13, wherein the mechanism further
comprises at least one stop member coupled to the inner sleeve for
selectively restricting motion of the first rotator.
16. The overshot of claim 10, wherein the coupling member comprises
a pair of lifting dogs pivotally mounted on an axle.
17. The overshot of claim 16, wherein each of the lifting dogs has
a first end for selectively engaging an article and a second end
for selectively engaging the first rotator.
18. The overshot of claim 17, wherein the coupling member further
comprises a spring disposed between the second ends of the lifting
dogs for biasing the second ends in opposing directions.
19. The overshot of claim 10, further comprising a wireline
connector coupled to the weight member for coupling the weight
member to a wireline.
20. A method of connecting or disconnecting a wireline from an
article, comprising: providing an overshot comprising a sleeve, a
coupling member having a latched state and an unlatched state
disposed at a first end of the sleeve, and a load-responsive
mechanism for alternating the coupling member between the latched
state and the unlatched state disposed at a second end of the
sleeve; coupling a wireline to the load-responsive mechanism;
aligning the article with the coupling member; and selectively
activating the load-responsive mechanism to alternate the coupling
member between the latched state where it engages the article and
the unlatched state where it disengages from the article.
21. The method of claim 20, wherein activating the load-responsive
mechanism comprises applying or releasing tension from the
wireline.
22. The method of claim 20, wherein activating the load-responsive
mechanism comprises moving the overshot upwardly.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of U.S. Provisional
Application No. 61/040,981 filed Mar. 31, 2008.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The invention relates generally to a wireline overshot for
connecting a wireline to an article within a borehole (or within a
downhole tool in the borehole) and/or for retrieving an article
from a borehole (or from a downhole tool disposed in the
borehole).
[0005] 2. Related Art
[0006] A "wireline" overshot is used to connect a wireline to an
article within a drill string. The article can be, but need not be
limited to, a wireline coring inner barrel, a soft material
sampling tool, a data gathering assembly, or an optional portion of
a downhole drilling assembly. The wireline overshot may also be
referred to as a fishing tool. In one example, the wireline
overshot connects to the article within the drill string by
latching over a spearhead coupled to the article. In another
example, the wireline overshot may latch onto the article within
the drill string by engaging a circular (or receiving) portion of
the article. The wireline is commonly a flexible wire rope but may
also be a solid wire (or "slickline"), synthetic braided rope, or
small-diameter, flexible tubing. The wireline is typically lowered
and raised by a winch.
[0007] In a typical core barrel retrieval operation, a wireline
overshot is lowered on the end of a wireline down the drill string,
where it latches onto an inner tube assembly of a core barrel
disposed within the drill string. The wireline overshot is then
pulled back to the surface with the attached inner tube assembly.
At the drill floor, the inner tube assembly is held in a clamp or
lowered onto the drill floor. An operator releases the wireline
overshot from the inner tube assembly manually and sets the
wireline overshot aside. In cases where the wireline overshot needs
to be unlatched from the inner tube assembly while still within the
drill string, the method of unlatching the wireline overshot is
commonly one of free-falling a release sleeve onto the wireline
overshot, tensioning and releasing the wireline to ratchet a
release pall, and repeated pulling or releasing of the wireline to
shear a release pin. All of these operations require the wireline
overshot to be reconfigured or rebuilt at the surface before it can
function as an overshot again.
SUMMARY
[0008] In a first aspect of the invention, an overshot comprises a
sleeve, a coupling member having a latched state and an unlatched
state disposed at a first end of the sleeve, and a load-responsive
toggle mechanism for alternating the coupling member between the
latched state and the unlatched state disposed at a second end of
the sleeve.
[0009] In a second aspect of the invention, an overshot comprises
an outer sleeve and a coupling member disposed a first end of the
outer sleeve. A first rotator is disposed within the outer sleeve
and configured to alternately engage and disengage from the
coupling member, thereby toggling the coupling member between an
unlatched state and a latched state. A second rotator is disposed
within the outer sleeve and configured to selectively displace and
rotate the first rotator in response to an applied load. A weight
member is disposed at a second end of the outer sleeve for applying
a load to the second rotator.
[0010] In a third aspect of the invention, a method of connecting
or disconnecting a wireline from an article comprises providing an
overshot comprising a sleeve, a coupling member having a latched
state and an unlatched state disposed at a first end of the sleeve,
and a load-responsive mechanism for alternating the coupling member
between the latched state and the unlatched state disposed at a
second end of the sleeve. The method includes coupling a wireline
to the load-responsive mechanism, aligning the article with the
coupling member, and selectively activating the load-responsive
mechanism to alternate the coupling member between the latched
state where it engages the article and the unlatched state where it
disengages from the article.
[0011] Other aspects of the invention will be apparent from the
following description and the appended claims.
BRIEF DESCRIPTION OF DRAWINGS
[0012] The accompanying drawings, described below, illustrate
typical embodiments of the invention and are not to be considered
limiting of the scope of the invention, for the invention may admit
to other equally effective embodiments. The figures are not
necessarily to scale, and certain features and certain views of the
figures may be shown exaggerated in scale or in schematic in the
interest of clarity and conciseness.
[0013] FIG. 1 is a cross-section of an overshot.
[0014] FIG. 2 is a cross-section of a toggle portion of the
overshot of FIG. 1.
[0015] FIG. 3 shows the overshot of FIG. 1 positioned atop an inner
tube assembly.
[0016] FIG. 4 shows a weight jar assembly of the overshot of FIG. 1
applying a load to an upper rotator of the overshot of FIG. 1 while
the overshot is in an unlatched state.
[0017] FIG. 5 shows the upper rotator of FIG. 4 pushing down on a
lower rotator of the overshot of FIG. 1.
[0018] FIG. 6 shows keys on the lower rotator of FIG. 5 sliding
into key slots on a key holder sleeve of the overshot of FIG.
1.
[0019] FIG. 7 shows the lifting dogs latching onto a spearhead at
the top of the inner tube assembly of FIG. 2.
[0020] FIG. 8 shows a weight jar assembly of the overshot of FIG. 1
applying a load to an upper rotator of the overshot of FIG. 1 while
the overshot is in the latched state.
[0021] FIG. 9 shows the keys of the lower rotator of the overshot
of FIG. 1 released from the key slots of the key holder sleeve of
the overshot of FIG. 1.
[0022] FIG. 10 shows the overshot of FIG. 1 suspended at the end of
a wireline.
[0023] FIG. 11 shows the overshot of FIG. 1 after it has engaged an
inner tube assembly within a drill string and has been retrieved to
the surface with the inner tube assembly.
DETAILED DESCRIPTION
[0024] FIG. 1 is a cross-section of an overshot 10 for connecting a
wireline to an article. The overshot 10 includes a cap 60 for
connection to a wireline. A weight jar assembly 44 is coupled to
the cap 60. The weight jar assembly 44 may include a weight bar 19
attached to the cap 60 by fasteners 21, e.g., thread-and-set
screws, and a jar stem 23 attached to the weight bar 19 by
fasteners 25, e.g., thread-and-set screws. The jar stem 23 is
received in a sleeve 22 and retained in the sleeve 22 by a jar
bushing 27 mounted at the upper end of the sleeve 22. A toggle head
13 is received in the sleeve 22 and is positioned below the jar
stem 23. A coupling member 14 is coupled to the toggle head 13 for
engaging an article of interest. The article of interest may be any
tool requiring a releasable connection with a wireline. For
example, the article may be an inner tube assembly used to collect
core samples from a subsurface formation, a soft material sampling
tool, a data gathering assembly, and a component of a downhole
drilling assembly. Connection and release of the overshot 10 from
the article can be made at the surface, within a borehole, or
within a tool disposed in the borehole.
[0025] For the purpose of engaging an article of interest, the
coupling member 14 is configured to mate with a coupling member on
the article of interest, or vice versa. The coupling member 14 and
the coupling member on the article of interest may have several
different configurations suited for the intended purposes. In the
example shown in FIG. 1, the coupling member 14 is a latch having a
pair of lifting dogs 18. A "lifting dog" is an elongated member
having one end terminating in a hook for engaging a part. In the
example shown in FIG. 3, the coupling member 14 is aligned to
engage a coupling member 16 on an article 12. In this example, the
coupling member 16 is a spearhead. Also, the article 12 is an inner
tube assembly latched into a core barrel 56. However, as previously
noted, the article 12 need not be limited to an inner tube
assembly. The lifting dogs 18 can be manipulated, as will be
described below, to toggle the coupling member 16 between a latched
state where the lifting dogs 18 engage the spearhead 16 to an
unlatched state where the lifting dogs 18 disengage from the
spearhead 16. It should be noted that the coupling members 14, 16
may have different configurations than those shown in FIG. 3. For
example, the coupling member 14 may be the spearhead while the
coupling member 16 is the latch configured to engage with and
disengage from the spearhead. In yet another example, one of the
coupling members 14,16 may be a latch and the other of the coupling
members 14,16 may be a receptacle for receiving the latch, wherein
the receptacle includes a surface for retaining the latch.
[0026] Returning to FIG. 1, the lifting dogs 18 are pivotally
coupled to an axle 26 of the toggle head 13. A spring 28 is
disposed between the upper ends 30 of the lifting dogs 18 to bias
the upper ends 30 of the lifting dogs 18 away from each other. The
pivot joint 33 between the lifting dogs 18 causes the lower ends 32
of the lifting dogs 18 (which include the hooks for engaging a
part) to be biased in a reverse direction to the upper ends 30 of
the lifting dogs 18. A toggle mechanism for moving the lifting dogs
18 between the latched and unlatched states includes a lower
rotator 34. In the unlatched state, the upper ends 30 of the
lifting dogs 18 are received within a bore of the lower rotator 34
so that the wall of the lower rotator 34 acts as a restraining ring
around the upper ends 30 of the lifting dogs 18. In this unlatched
state, the upper ends 30 of the lifting dogs 18 are forced towards
each other against the force of the spring 28 and the lower ends 32
of the lifting dogs 18 are forced away from each other. The lower
rotator 34 is axially movable along the toggle head 13 and sleeve
22. To transition the overshot 10 to a latched state, the lower
rotator 34 is moved a sufficient distance in an upward direction to
release the upper ends 30 of the lifting dogs 18 from the lower
rotator 34. Once the upper ends 30 are released, the spring 28
would move the upper ends 30 away from each other, thereby causing
the lower ends 32 of the lifting dogs 18 to move towards each other
and latch onto the spearhead 16, as will be further described
below. The shaft 24 of the toggle head 13 includes a flange 36, and
a spring 38 is arranged between an upper end 39 of the lower
rotator 34 and the flange 36 to hold the lower rotator 34 in place
about the shaft 24. The shaft 24 is coupled to the axle 26 to which
the lifting dogs 18 are pivotally mounted.
[0027] The toggle mechanism includes an upper rotator 40 disposed
about the shaft 24. The upper rotator 40 is held in place above the
lower rotator 34 (and about the shaft 24) by a spring 42. The term
"rotator," as used herein and above, means a part that can rotate
or that can rotate another part. In one example, the upper rotator
40 is configured to rotate the lower rotator 34. The upper rotator
40 is slidable along the shaft 24 upon application of a load to the
upper rotator 40 by the weight jar assembly 44. For the upper
rotator 40 to be slidable, the load applied by the weight jar
assembly 44 must be sufficient to overcome the biasing force of the
spring 42 holding the upper rotator 40 in place. As will be further
explained below, the load should also be sufficient to overcome the
biasing force of the spring 38 holding up the lower rotator 34, or
the biasing force of the spring 38 holding up the lower rotator 34
should be less than that of the spring 42 holding up the upper
rotator 40. A wireline (not shown) coupled to the weight bar 19
through the cap 60 is used to control the position of the jar stem
23 (of the weight jar assembly 44) within the sleeve 22. The jar
stem 23 is movable between an upper position limited by the jar
bushing 27 (at the upper end of the sleeve 22) and a lower position
limited by the upper rotator 40. When the weight jar assembly 44
rests on the upper rotator 40, it applies a load to the upper
rotator 40. As will be explained below, this load assists in
shifting the lifting dogs 18 between the latched and unlatched
states. Contact is required between the jar stem 23 and the upper
rotator 40 to allow the weight jar assembly 44 to apply a load to
the upper rotator 40. Contact can be achieved in one of two ways.
One way is by letting go of tension in the wireline (not shown)
coupled to the weight bar 19 so that the jar stem 23 slides down
the shaft 24 to contact the upper rotator 40. The other way is by
moving the overshot 10 upwardly so that the upper rotator 40 slides
up the shaft 24 to contact the jar stem 23. A jar bushing 51 is
disposed within the sleeve 22 and locked to the sleeve 22 by
fasteners 53. A key holder sleeve 46 is mounted inside the sleeve
22 and attached to the jar bushing 51. The key holder sleeve 46 is
generally concentric with the upper rotator 40, the lower rotator
34, and the shaft 24. The jar stem 23 is sized to slide through the
jar bushing 51 into the key holder sleeve 46 as needed to contact
the upper rotator 40. The jar stem 23 includes a bore 47 which fits
over the shaft 24, thereby allowing the jar stem 23 to travel along
the shaft 24.
[0028] In FIG. 2, the key holder sleeve 46 includes a plurality of
keys 48. Some of the keys 48 are shortened to define a plurality of
key slots 50. Stop pins 52 are inserted into the ends of some of
the keys 48, resulting in a portion of the key slots 50 having stop
pins 52 and a portion of the key slots 50 not having stop pins 52.
A plurality of keys 54 is fastened to the lower rotator 34. The
keys 54 are shaped to slide into the key slots 50 when aligned with
the key slots 50. The stop pins 52 act to restrict the upward
motion of the keys 54 when the keys 54 are received in the portion
of the key slots 50 containing stop pins 52. In the example shown
in FIG. 2, the keys 48, 54 have tapered ends 49, 55, respectively.
When the weight of the upper rotator (40 in FIG. 1) is applied to
the lower rotator 34, the tapered ends 49, 55 along with the force
of the spring (38 in FIG. 1) rotate the lower rotator 34 for
alignment from one slot to halfway to the next slot on the left.
When the weight of the upper rotator (40 in FIG. 1) is lifted by
the spring (42 in FIG. 1), the lower rotator 34 completes its
rotation into the next slot.
[0029] FIG. 3 shows the overshot 10 positioned on top of an inner
tube assembly 12 latched into a core barrel 56. The overshot 10 is
in an unlatched state, with the lifting dogs 18 slid down the
spearhead 16 and held open by the shoulder 57 of the spearhead 16.
This frees the lower rotator 34 to rotate without the friction that
would be caused by the spring 38. In the example shown in FIG. 3,
tension in the wireline has been relaxed, allowing the weight jar
assembly 44 to rest on and apply a load to the upper rotator 40.
Relative motion between the overshot 10 and the wireline (not
shown) is used to bring the jar stem 23 of the weight jar assembly
44 in contact with the upper rotator 40. Relative motion can be
achieved by releasing the weight jar assembly 44 from above, e.g.,
through relaxation of tension in the wireline coupled to the weight
jar assembly 44, or by moving the overshot 10 upwardly. The weight
jar assembly 44 applies weight to the upper rotator 40 and, as
shown in FIG. 4, causes the upper rotator 40 to slide down the key
holder sleeve 46 and engage the lower rotator 34. As shown in FIG.
5, the upper rotator 40 pushes the lower rotator 34 down until the
keys 54 (on the lower rotator 34) are positioned below the keys 48
(on the key holder sleeve 46). As previously explained, the load
applied by the weight jar assembly (44 in FIG. 1) must be
sufficient to overcome the force of the spring (42 in FIG. 1)
holding up the upper rotator 40 and the force of the spring (38 in
FIG. 1) holding up the lower rotator 34. The lower rotator 34 then
rotates clockwise (looking down) as the tension of the spring (38
in FIG. 1) pushes the lower rotator 34 upwardly against the beveled
surface 62 of the upper rotator 40. The keys 54 slide into the key
slots 50 without the stop pins 52, as shown in FIG. 6. The lower
rotator 34 moves upwardly as the keys 54 slide upwardly inside the
key slots 50. As shown in FIG. 7, this causes the upper ends 30 of
the lifting dogs 18 to be released from the lower rotator 34. The
spring 28 moves the upper ends 30 of the lifting dogs 18 outwardly,
which causes the lower ends 32 of the lifting dogs 18 to move
inwardly and latch onto the spearhead 16. In the latched state, the
weight jar assembly 44 is held again in tension to avoid exerting
weight on the upper rotator 40, and the upper rotator 40 is held
above the lower rotator 34 by the spring 42. The lower rotator 34
is held in place by the keyed connection described above and the
force of the spring 38.
[0030] To release the lifting dogs 18 from the spearhead 16, the
weight jar assembly 44 is again brought into contact with the upper
rotator 40 to apply a load to the upper rotator 40, as shown in
FIG. 8. As previously explained, the weight jar assembly 44 can
either slide down to contact the upper rotator 40, or the overshot
10 can be moved upwardly to allow the upper rotator 40 to slide up
and contact the weight jar assembly 44. The upper rotator 40, under
the load of the weight jar assembly 44, slides down the key holder
sleeve 46 to engage the lower rotator 38 and push the lower rotator
38 down so that, as shown in FIG. 9, the keys 54 are positioned
below the keys 48. For this to happen, the load applied by the
weight jar assembly 44 must be sufficient to overcome the biasing
force of the spring (42 in FIG. 1) holding up the upper rotator 40
and the biasing force of the spring (38 in FIG. 1) holding up the
lower rotator 40. The biasing force of the spring (38 in FIG. 1)
holding up the lower rotator 40 and the beveled surface 62 of the
upper rotator 40 again act to rotate the lower rotator 38 clockwise
so that the keys 54 are aligned with the key slots 50 containing
the stop pins 52. As shown in FIG. 8, this action returns the lower
rotator 38 to the position where it constrains the upper ends 30 of
the lifting dogs 18, thereby causing the lower ends 32 of the
lifting dogs 18 to separate from the spearhead 16.
[0031] The overshot 10 can be used to connect a wireline to an
article, such as an oilfield tool, either at the surface or in a
borehole. The overshot 10 can be disconnected from the article by
the same action used in connecting the overshot 10 to the article,
as described above. The overshot 10 can be used in any drilling or
wireline operation. For illustration purposes, FIG. 10 shows the
overshot 10 suspended at the end of a wireline 70 in preparation
for lowering the overshot 10 into a drill string 72 containing a
core barrel with an inner tube assembly. The drill string 72 is
disposed in a borehole 73 drilled in a subsurface formation 75.
FIG. 11 shows the overshot 10 after it has engaged the inner tube
assembly 12 and been retrieved to the surface with the inner tube
assembly 12. A handling arm 74 holds the inner tube assembly 12
while the overshot 10 is disengaged from the inner tube assembly 12
as described above.
[0032] While the invention has been described with respect to a
limited number of embodiments, those skilled in the art, having
benefit of this disclosure, will appreciate that other embodiments
can be devised which do not depart from the scope of the invention
as disclosed herein. Accordingly, the scope of the invention should
be limited only by the attached claims.
* * * * *