Note: Descriptions are shown in the official language in which they were submitted.
'79261
DRILLING STABILIZER INCLUDING
MECHANICAL INTERLOCK AND DISENGAGEMENT DEVIGE
1 Background of the Invention
Oil field drilling operations utilizing a rotary drill
string and having a section or sections of drill collar immediately
above the drill bit require the application of a drilling stabilizer
to the drill collar section or sections in order to minimize the
seizure within the drill bore of the drill collar as well as to
stabilize the drill string during drilling operations.
It is desired that a drilling stabilizer be quickly
connected or disconnected to the drill collar, and that a minimum
of manual operations be involved during the connecting or disconnect-
ing of the stabilizer. It is further desirable to employ a drilling
stabilizer which can be affixed to the collar section in such a man-
ner that each stabilizer can be affixed at any desired interval
from the preceding stabilizer. Those familiar with oil field opera-
tions will recognize that the various combinations and spacings
of drilling stabilizers are often determinative in obtaining a
desired drilling result. It is also advantageous to utilize a drill-
i ing stabilizer which is durable throughout a particular drilling
operation and which is readily adaptable to any number of dissimilar
drill collars utilized in oil field operations around the world.One such drilling stabilizer which has frequently been used is
described and claimed in U.S. Patent No. 3,916,998 issued November
~ 4, 1975 to Samuel L. Bass, Jr., et al, entitled Drilling Stabilizer
j and Method (hereinafter referred to as the '998 patent).
The drilling stabilizer described in the '998 patent
comprises fundamentally a rigid main sleeve having an axial passage-
way extending therethrough and a rib midway of the passageway against
each side which a pair of slideably received rings abut. An end
cap is threadedly engaged into each end of the rigid main sleeve
in such a manner that as the end cap is threaded into the sleeve
the inner ring of a pair of rings is forcefully urged into a
clamping engagement with the outer surface of the drill collar.
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1 Likewise, the outer ring is forced against the inner surface of
the main sleeve. Consequently, the device in the '998 patent can
be selectively applied to any location on a drilling collar. More-
over, since only the interior surface of the inner split ring con-
tacts the drill collar, flexibility within the drill collar is not
sacrificed by the application of numerous drilling stabilizers.
A shortcoming of the device in the '998 patent, however,
has been that once the drilling stabilizer is successfully clamped
onto the drill collar, it is frequently difficult to disengage and
remove the stabilizer from the collar. Those familiar with drilling
operations appreciate that mere removal of the end cap from the
rigid main sleeve often does not disengage the outer split ring
from the inner split ring on either or both pairs of rings. Con-
sequently, although the end cap has been threadedly disengaged
from the rigid main sleeve, the corresponding pair of split rings
still exerts a force or forces clamping the stabilizer to the
collar. A common practice for disengaging the stabilizer from the
collar has been to strike the stabilizer forcefully with any suit-
able device such as a large hammer. Such an operation clearly
requires additional manual effort, tools, time and is also
destructive of the stabilizer itself.
The present invention is directed toward the elimination
of the shortcomings of a drilling stabilizer similar to the one
shown and described in the '998 patent. The present invention
described and claimed hereinafter employs an annular ring and an
annular groove on the interior surface of the outer split ring and
an annular groove and annular rib on the exterior surface of the
end cap whereby the rib of the outer ring is substantially disposed
within the groove of the end cap and the rib of the end cap is
substantially disposed within the groove of the outer ring. The
outer ring is preferably urged into engagement with the end clamp
before threading the end cap into the main sleeve. The interaction
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between the groove and the rib on the ring with the rib and
groove respectively of the end cap produces a locking action
in the axial direction. The result of the axial interlock
configuration is that the outer split ring necessarily follows
the end cap as the end cap is threadedly disengaged from the
rigid main sleeve, thereby unclamping the pair of rings from
the sleeve and drill collar. Those familiar with drilling
operations will realize that as the second end cap is threadedly
disengaged from the drilling stabilizer that the stabilizer
itself can be axially moved along the drill collar for
; repositioning, engagement and disengagement with the collar.
According to the invention there is provided an
improved drilling stabilizer having a substantially cylindrical
rigid main sleeve, an axial passageway extending the entire
length of the rigid main sleeve and including an inwardly
extending fixed abutment means medially of the passageway.
¦ The innermost extent of the abutment means defines an
3 opening of sufficient size to permit the sleeve to be slideably
received over a drill collar. Extending radially outwardly
, 20 of the rigid main sleeve is a flange. A clamping means
¦ positioned internally of the rigid main sleeve adjacent the
, fixed abutment means includes a first and second pair of
, overlying inner and outer split rings each having a single
opening. Each pair of split rings is positioned on opposite -
sides of the abutment means with one ring of each pair of
split rings engaging the abutment means. Each pair of rings
is of sufficient diameter to be slideably received over the
drill collar and has abutting conical surfaces oriented so
that the axial movement of one split ring of each pair relative
to the other split ring of the same pair results in a clamping
or unclamping of the inner ring to the drill collar and the
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outer ring to the rigid main sleeve. An end cap is slideably
and threadedly received by the rigid main sleeve to activate
the clamping means. The improvement comprises a mechanical
interlock means for engagement of the outer split ring of one
pair of rings to the end cap whereby the outer ring is dis-
engaged axially from the inner ring of the pair as the end
cap is threadedly removed from the main sleeve. As a
consequence from the latter disengagement the pair of rings
is unclamped from the rigid main sleeve in the drill collar.
Advantageously the interlock means engagement of
the outer ring to the end cap includes a radially projecting
rib circumferentially disposed on the end cap in proximity
to the end of the cap which engaged the outer split ring.
An annular groove in the end cap trails the rib of the end cap
into the outer ring when the outer split ring is engaged by
, the end cap. A circumferential rib projects radially inwardly
Jl from the outer ring such that when the end cap engages the
j outer split ring, the rib of the outer ring is substantially
disposed within the annular groove on the end cap. In communi-
cation with an interior cylindrical surface of the outer split
ring is an annular groove. The rib of the end cap is substan-
tially disposed within the annular groove of the outer split
ring when the end cap engages the latter. Also included are
means for biasing the groove and rib of the outer split ring
toward the rib and groove collar respectively, of the end cap
as the end cap engages the outer split ring.
f Preferably the groove and the rib on the end cap
share a common wall and the groove and the rib on the outer
split ring share a common end wall.
~ 30 Conveniently the means for biasing the groove and
', rib of the outer split ring is provided by the resiliency of
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the outer split ring resulting from the split in the latter.
As the end cap is threadedly engaged by the rigid
main sleeve, the outer split ring is urged against the inner
split ring and is urged into clamping engagement with the rigid
main sleeve. The inner ring is urged into clamping engagement
with the drill collar and, as the end cap is threadedly dis-
engaged from the main sleeve, the outer split ring is axially
disengaged from the inner split ring thereby unclamping the
inner split ring from the drill collar and the outer split ring
from the main sleeve.
It is an object of the present invention to provide
a drilling stabilizer which is easily applied to and removed
from a drill collar. -
Another object of the present invention is to utilize
a clamping means of the drill stabilizer which allows the
stabilizer to remain clampingly fixed to the drill collar
without unduly restricting the flexibility of the collar.
A still further object of the present invention is
to provide a clamping means in the drilling stabilizer which,
when actuated by the end cap effectively affixes the stabilizer
to the drill collar, and upon disengagement of the end cap
from the rigid main sleeve unclamps the clamping means thereby
allowing the drilling stabilizer to be axially repositioned or
removed from the drill collar.
It is yet a further object of this invention to
provide a clamping means on a drilling stabilizer which is
effectively and automatically unclamped without applying
shock forces to the drilling stabilizer or without the use
of auxiliary tools other than those necessary to threadedly
remove the end cap from the rigid main sleeve.
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1 Further objects and other features and advantages of the
present invention will be apparent in the following descxiption
of the preferred embodiments of the invention, given for the
purpose of disclosure and taken in conjunction with the accompany-
ing drawings.
Brief Description of the Drawings
Fig. 1 is an exploded vertical view of the upper portion
of the drilling stabilizer showing the rigid main sleeve, an inner
split locking ring, an outer split locking ring and one end cap
with a clutch jaw.
Fig. 2 is a sectional view of part of the rigid main
' sleeve, the slideably received drill collar, the inner and
, outer split locking rings and a portion of the end cap prior to
~ activating the clamping action of the inner and outer rings.
j Fig. 3 is a sectional view of a portion of the rigid
main sleeve, the drill collar, the inner and outer split rings,
and a portion of the end cap after the actuation of the
clamping effect.
Fig. 4 is an exploded vertical view of the upper
20 portion of the drilling stabilizer showing the rigid main sleeve,
an inner split locking ring, an outer split locking ring and
one end cap with a clutch jaw.
Fig. 5 is a sectional view of part of the rigid main -
sleeve, the slideably received drill collar, the inner and
outer split locking rings and a portion of the end cap prior
to activating the clamping action of the inner and outer rings.
J Fig. 6 is a sectional view of a portion of the rigid
main sleeve, the drill collar, the inner and outer split rings,
` and a portion of the end cap after the actuation of the clamping
30 effect.
Description of the Preferred Embodiments
Fig. 1. shows the upper portion of the drilling stabili-
- ~- zer as it is commonly situated in a well bore. A main sleeve 2
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1 having one or more outwardly projecting spiral flanges 4 has a
substantially cylindrical internal passageway 9 extending axially
the length of the main sleeve 2 and is suitable for receiving a
drill collar 54 or other similar body. An inwardly projecting
abutment means, for example an annular rib 56 (Figs. 2, 3), having
an upper shoulder 50 and a lower shoulder not shown herein is
disposed medially in the interior of the main sleeve 2. An inner
split locking ring 74 having an open slot 77, an exterior conical
surface 76 and an interior cylindrical surface 78 is slideably
received into the passageway 9 of the main sleeve 2. The inner
locking ring 74 is of a smaller diameter than the inner annular
rib 56 of the main sleeve 2; therefore, the inner ring 74 is
slideably received in passageway 9 of main sleeve 2 and abuts the
shoulder 50 of the rib 56.
The outer locking ring 83 has an open slot 81, a cylindri-
cal exterior surface 70, a substantially cylindrical interior
surface 80 and a conical interior surface 72 conforming to th~
conical surface 76 of the inner split ring 74. The inner ring
74 substantially conforms to and underlies the conical surface
72 of the split ring 83 as shown in Fig. 2. On the upper portion
of the interior cylindrical surface 80 of the outer locking ring
83 is disposed an inwardly projecting annular rib 82. An annular
groove 84 is disposed immediately below the rib 82 as shown in
Fig. 1, the groove 84 communicating with the interior cylindrical
surface 80 of the outer ring 83. In the particular embodiment
shown, the groove 84 and the rib 82 have a common radially-aligned
wall 86. The outer split ring 83 is urged by means of any
suitable leverage device (not shown) onto the end cap 12 and
into locking engagement with said end cap before the end cap is
threadedly engaged to the main sleeve 2.
An end cap 12 having a sleeve 13 of a greater diameter
than the projecting member 18 is slideably received by the passage-
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1 way 9 of the main sleeve 2. The threads 16 of the end cap 12
are compatible with the threads 6 of the main sleeve 2 thereby
permitting threaded engagement of the end cap 12 with the main
sleeve 2 until the leading shoulder 15 of the sleeve 13 abuts
the leading surface 7 of the main sleeve. As depicted in Fig.
1, an outwardly projecting rib 22 is disposed on the projecting
member 18 such that the lead wall 28 of the rib 22 is first
received by the main sleeve 2. Contiguous to and having a
' common wall 26 with the rib 22 is an annular groove 20 communica-
10 ting with the exterior of the projecting member 18 and having
a trailing wall 24. When the end cap 12 is threadedly engaged
into the main sleeve 2, the inner ring 74 abutting the shoulder
50 and the outer ring 83 are axially forced together whereby
' the inner ring 74 is urged radially inwardly to clampingly engage
the exterior surface 60 of the drill collar 54 while the outer
ring 83 is urged radially outwardly by the internal ring 74 into
` clamping engagement with the interior surface of the main sleeve
2. Further engagement of the threads 16 with the compatible
threads 6 allows axial forces to be transmitted by the lead
20 wall 28 and the trailing wall 24 of the end cap 12 to a trailing
J wall 88 and a leading wall 90 respectively of the outer ring,
thereby urging the outer ring 83 axially toward the inner ring 74
, thereby increasing the clamping force between the inner ring 74and the drill collar 54 and the outer ring 83 and the main
sleeve 2 as shown in Fig. 3.
As the end cap 12 is threadedly disengaged from the main
sleeve 2, the common wall 26 of the end cap is urged against a
common wall 86 of the outer ring 83 whereby the outer ring 83
is successfully and forceably disengaged from the inner ring 74.
30 The disengagement of the outer ring 83 from the inner ring 74,
therefore, reduces the radial forces of the inner ring 74 upon
; the drill collar 54 and the radial forces of the outer ring 83
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1 upon the main sleeve 2 thereby releasing the upper portion of
the main sleeve 2 from clamping engagement with the drill
collar 54.
Another embodiment of the new drilling stabilizer is
shown in Figs. 4, 5 and 6. The inner locking ring 44 is of a
smaller diameter than the inner annular rib 56 of the main
sleeve 2; therefore, the inner ring 44 is slideably received in
passageway 9 of main sleeve 2 and abuts the shoulder 50 of
; the rib 56.
The outer locking ring 30 has an open slot 31, a -
cylindrical exterior surface 42, a conical exterior surface 19
and a substantially cylindrical interior surface 43. The in- `
ner ring 44 substantially overlies the conical surface 19 of
the split ring 30 as shown in Fig. 5. On the upper portion of
the interior cylindrical surface 43 of the outer locking ring
30 is disposed an inwardly projecting annular rib 32. An
annular groove 34 is disposed immediately below the rib 32 as
shown in Fig. 4, the groove 34 communicating with the interior
cylindrical surface 43 of the outer ring 30. In the particular
embodiment shown, the groove 34 and the rib 32 have a common
radially-aligned wall 40. The outer split ring 30 is urged by
means of any suitable leverage device (not shown) onto the end
cap 12 and into locking engagement with said end cap before
the end cap is threadedly engaged to the main sleeve 2.
An end cap 12 having a sleeve 13 of a greater diameter
than the projecting member 18 is slideably received by the
passageway 9 of the main sleeve 2. The threads 16 of the end
cap 12 are compatible with the threads 6 of the main sleeve 2
thereby permitting threaded engagement of the end cap 12 with
the main sleeve 2 until the leading shoulder 15 of the sleeve
13 abuts the leading surface 7 of the main sleeve. As depicted
in Fig. 4, an outwardly projecting rib 22 is disposed on the
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1 projecting member 18 such that the lead wall 28 of the rib 22 ~ .
is first received by the main sleeve 2. Contiguous to and having
a common wall 26 with the rib 22 is an annular groove 20 communi-
cating with the exterior of the projecting member 18 and having
a trailing wall 24. When the end cap 12 is threadedly engaged .
into the main sleeve 2, the inner ring 44 abutting the shoulder
50 and the outer ring 30 are axially forced together whereby
the inner ring 44 is urged radially outwardly to clampingly
engage the interior surface of the main sleeve 2 while the outer
ring 30 is urged radially inwardly by the internal ring 44 into
clamping engagement with the exterior surface 60 of the drill .
collar 54. Further engagement of the threads 16 with the
compatible threads 6 allows axial forces to be transmitted by
the lead wall 28 and the trailing wall 24 of the end cap 12 to
the trailing wall 38 and the leading wall 36 respectively of
the ou*er ring, thereby urging the outer ring 30 axially toward
the inner ring 44 thereby increasing the clamping force between
the inner ring 44 and the main sleeve 2 and the outer ring 30 -
and the drill collar 54 as shown in Fig. 6.
As the end cap 12 is threadedly disengaged from the
main sleeve 2, the common wall 26 of the end cap is urged against
the common wall 40 of the outer ring 30 whereby the outer ring
30 is successfully and forceably disengaged from the inner ring
44. The disengagement of the outer ring 30 from the inner ring
44, therefore, reduces the radial forces of the inner ring 44
upon the main sleeve 2 and the radial forces of the outer ring ::
30 upon the drill collar 54 thereby releasing the upper portion : .
of the main sleeve 2 from clamping engagement with the drill
collar 54.
It is understood that a pair of rings and an end cap
similar to the rings 30, 44 and the end cap 12 as shown in Fig.
4 are also received by the lower end of the main sleeve 2,
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1 thereby clamping the bottom portion of the main sleeve 2 onto
the drill collar 54.
. It is understood that in the preferred embodiment of
the present invention a pair of rings and an end cap similar
to the rings 83, 74 and the end cap 12 as shown in Fig. 1 are
also received by the lower end of the main sleeve 2, thereby
;~ clamping the bottom portion of the main sleeve 2 onto the
drill collar 54.
In oil field operations, therefore, the invention as
described and claimed herein in quickly and easily engaged to
or disengaged from the drill collar. A typical procedure for
disengagement requires the slips (not shown) to be set below
the stabilizer. The upper end cap 12 is "broken out" or threadedly
disengaged from the main sleeve 2 with, for example, a tong
(not shown). The drill collar 54 is then raised through the
slips and set at a level appropriate for the lower end cap (not
shown) to be broken out from the main sleeve 2. Before the
lower end cap is broken out from the main sleeve 2, it is
j desirable to support the drilling stabilizer, for example, by
an air hoist line or cat line (not shown). The final step is
to break out the lower end cap from the main sleeve 2. As the
lower end cap is threadedly disengaged from the main sleeve 2,
the clamping forces affixing the stabilizer to the drill collar
54 have been reduced, and the stabilizer is now free to slide on
-~ the collar. For reasons of safety, the air hoist line or cat
line should be attached to the stabilizer prior to breaking out
the lower end cap for support of the stabilizer as it becomes
free to slide on the collar.
It is, therefore, clear that the present invention is
30 a new and useful design for a drilling stabilizer which is
both suitable for downhole use in the oil field while at the
same time fulfills all the objectives as previously expressed
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1 herein. The preferred embodiments of the present invention
have been given for the purpose of disclosure, and changes may
be made which are within the spirit and the scope of the
invention as defined by the claims, specification and drawings ;: :
herein.
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