U.S. patent number 3,912,026 [Application Number 05/445,055] was granted by the patent office on 1975-10-14 for fluid pressure locked well drilling tool.
This patent grant is currently assigned to Baker Oil Tools, Inc.. Invention is credited to David V. Chenoweth, Talmadge L. Crowe, David M. McStravick.
United States Patent |
3,912,026 |
Crowe , et al. |
October 14, 1975 |
Fluid pressure locked well drilling tool
Abstract
A telescopic bumper jar is made up in a string of drill collars
in a well drilling pipe string, and fluid pressure holds the tool
in a telescopically contracted condition with opposing shoulders
abutting to prestress the tool to prevent fatigue during drilling.
In one form the tool is locked by a fluid pressure expanded locking
sleeve coengaged between the telescopic bodies. In another form a
differential piston responsive to pressure in the tool and to
hydrostatic pressure in the drill pipe prestresses the tool. In
both forms, the pressure is relieved by a tripping plug dropped
through the drill pipe.
Inventors: |
Crowe; Talmadge L. (Houston,
TX), Chenoweth; David V. (Honolulu, HI), McStravick;
David M. (Houston, TX) |
Assignee: |
Baker Oil Tools, Inc. (Los
Angeles, CA)
|
Family
ID: |
23767437 |
Appl.
No.: |
05/445,055 |
Filed: |
February 25, 1974 |
Current U.S.
Class: |
175/297; 175/303;
166/239 |
Current CPC
Class: |
E21B
31/113 (20130101) |
Current International
Class: |
E21B
31/00 (20060101); E21B 31/113 (20060101); E21B
001/10 () |
Field of
Search: |
;175/296,297,301,302,303,321 ;166/154,239,187,212,120 ;267/137
;64/23 ;285/302 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Leppink; James A.
Attorney, Agent or Firm: Kriegel; Bernard
Claims
We claim:
1. In a well drilling tool: a telescopic assembly comprising an
elongated inner body and an elongated outer body, means
interconnecting said bodies for rotation as a unit and for
telescopic movement, said bodies having opposing shoulders limiting
telescopic contraction, fluid pressure responsive means for holding
said bodies in telescopically contracted condition with said
shoulders tightly engaged, said fluid pressure responsive means
including means preventing all relative longitudinal movement
between said bodies from said contracted condition to retain said
shoulders tightly engaged, and trigger means operable by a tripping
device for releasing said fluid pressure responsive means to permit
disengagement between said shoulders and telescopic extension of
said bodies with respect to each other.
2. In a well drilling tool as defined in claim 1, said bodies
having additional opposed shoulders spaced apart when said bodies
are telescopically contracted and adapted to produce a hammer blow
upon telescopic extension of said bodies.
3. In a well drilling tool as defined in claim 1, said fluid
pressure responsive means comprising means frictionally holding
said bodies against telescopic movement.
4. In a well drilling tool as defined in claim 1, said fluid
pressure responsive means comprising expansible means between said
bodies expanded by fluid pressure.
5. In a well drilling tool as defined in claim 1, said fluid
pressure responsive means comprising a pair of sleeves, said bodies
having walls defining an annular space receiving said pair of
sleeves therebetween, said sleeves defining a pressure chamber
therebetween whereby said sleeves are relatively expanded to
frictionally lock said bodies together.
6. In a well drilling tool as defined in claim 1, said fluid
pressure responsive means comprising a pair of sleeves, said bodies
having walls defining an annular space receiving said pair of
sleeves therebetween, one of said sleeves being fixed on one of
said bodies, the other of said sleeve and the other of said bodies
having opposing friction surfaces, said sleeves defining a pressure
chamber therebetween for expanding said other sleeve into
frictional locking engagement with said other body.
7. In a well drilling tool as defined in claim 1, said fluid
pressure responsive means comprising a pair of sleeves, said bodies
having walls defining an annular space receiving said pair of
sleeves therebetween, said sleeves defining a pressure chamber
therebetween whereby said sleeves are relatively expanded to
frictionally lock said bodies together, and means operable by said
trigger means to exhaust said pressure chamber.
8. In a well drilling tool as defined in claim 1, said fluid
pressure rexponsive means comprising a pair of sleeves, said bodies
having walls defining an annular space receiving said pair of
sleeves therebetween, one of said sleeves being fixed on one of
said bodies, the other of said sleeves and the other of said bodies
having opposing friction surfaces, said sleeves defining a pressure
chamber therebetween for expanding said other sleeve into
frictional locking engagement with said other body, and means
operable by said trigger means to exhaust said pressure
chamber.
9. In a well drilling tool as defined in claim 1, said fluid
pressure responsive means comprising a pair of metal sleeves, means
joining said sleeves in concentric circumferentially spaced
relation to form a pressure chamber therebetween, filler means for
filling said chamber, and relief means for venting said chamber
responsive to said trigger means.
10. In a well drilling tool as defined in claim 1, said fluid
pressure responsive means comprising a pair of metal sleeves, means
joining said sleeves in concentric circumferentially spaced
relation to form a pressure chamber therebetween, filler means for
filling said chamber, a relief tube communicating with said chamber
and having a free end, said inner body having an opening through
which said free end extends, and said trigger means comprising a
sleeve shiftable relative to said inner body and having a shearing
edge for shearing off said free end upon movement of said trigger
sleeve.
11. In a well drilling tool as defined in claim 1, said fluid
pressure responsive means comprising a pair of metal sleeves, means
joining said sleeves in concentric circumferentially spaced
relation to form a pressure chamber therebetween, filler means for
filling said chamber, and relief means for venting said chamber
responsive to said trigger means, said inner body and the inner
sleeve being threadedly interconnected, the outer sleeve and said
outer body having opposed friction surfaces co-engaged when
pressure is applied to said chamber to frictionally lock said
bodies together.
12. In a well drilling tool as defined in claim 1, said fluid
pressure responsive means comprising means defining a pressure
chamber containing a body of fluid, piston means having a first
pressure responsive area exposed to the fluid in said chamber and a
second pressure responsive area exposed to hydrostatic pressure,
said bodies having opposing pressure responsive areas exposed to
the pressure of fluid in said chamber, and said trigger means being
operable to vent the fluid from said chamber.
13. In a well drilling tool as defined in claim 1, said fluid
pressure responsive means comprising means defining a pressure
chamber containing a body of fluid, piston means having a first
pressure responsive area exposed to the fluid in said chamber and a
second pressure responsive area exposed to hydrostatic pressure,
said bodies having opposing pressure responsive areas exposed to
the pressure of fluid in said chamber, said trigger means and one
of said bodies having companion sealing means normally confining
said fluid in said chamber, and said chamber being vented upon
movement of said trigger means.
14. In a well drilling tool as defined in claim 1, said fluid
pressure reponsive means comprising means defining a pressure
chamber containing a body of fluid, piston means having a first
pressure responsive area exposed to the fluid in said chamber and a
second pressure responsive area exposed to hydrostatic pressure,
said bodies having opposing pressure responsive areas exposed to
the pressure of fluid in said chamber, means defining an
atmospheric chamber, said piston means having a third pressure
responsive area exposed to said atmospheric chamber, and said
trigger means being operable to vent the fluid from said pressure
chamber to said atmospheric chamber.
15. In a well drilling tool as defined in claim 1, said fluid
pressure responsive means comprising means defining a pressure
chamber containing a body of fluid, piston means having a first
pressure responsive area exposed to the fluid in said chamber and a
second pressure responsive area exposed to hydrostatic pressure,
said bodies having opposing pressure responsive areas exposed to
the pressure of fluid in said chamber, means defining an
atmospheric chamber, said piston means having a third pressure
responsive area exposed to said atmospheric chamber, said trigger
means and one of said bodies having companion sealing means
normally confining said fluid in said chamber, and said trigger
means being operable to vent the fluid from said pressure chamber
to said atmospheric chamber.
16. In a well drilling tool as defined in claim 1, said fluid
pressure responsive means comprising means defining a pressure
chamber containing a body of fluid, piston means having a first
pressure responsive area exposed to the fluid in said chamber and a
second pressure responsive area exposed to hydrostatic pressure,
said bodies having opposing pressure responsive areas exposed to
the pressure of fluid in said chamber, said trigger means being
operable to vent the fluid from said chamber, and said first
pressure responsive area being smaller than said second pressure
responsive area, whereby the pressure of said fluid in said chamber
is greater than said hydrostatic pressure.
17. In a well drilling tool as defined in claim 1, said fluid
pressure responsive means comprising means defining a pressure
chamber containing a body of fluid, piston means having a first
pressure responsive area exposed to the fluid in said chamber and a
second pressure responsive area exposed to hydrostatic pressure,
said bodies having opposing pressure responsive areas exposed to
the pressure of fluid in said chamber, said trigger means being
operable to vent the fluid from said chamber, and said opposing
pressure responsive areas of said bodies comprising a hammer and an
anvil.
18. In a well drilling tool: a telescopic assembly comprising an
elongated inner body having means at one end for connection in a
drill string, an elongated outer body having means at one end for
connection in said drill string, the other ends of said bodies
being telescopically engaged, means interconnecting said bodies for
rotation as a unit and for telescopic movement, said bodies having
opposing shoulders limiting telescopic contraction, fluid pressure
responsive means between said bodies for holding said bodies
telescopically contracted with said shoulders tightly abutting, and
trigger means shiftably carried by said inner body for relieving
said fluid pressure responsive means upon movement of said trigger
means, said fluid pressure responsive means including fluid
pressure expansible friction locking means interposed between said
bodies, and vent means communicating with said expansible means and
openable by said trigger means upon movement of the latter.
19. In a well drilling tool as defined in claim 18, said bodies
having additional opposed shoulders spaced apart when said bodies
are telescopically contracted and adapted to produce a hammer blow
upon telescopic extension of said bodies.
20. In a well drilling tool as defined in claim 18, said fluid
pressure responsive means comprising a pair of sleeves, said bodies
having walls defining an annular space receiving said pair of
sleeves therebetween, said sleeves defining a pressure chamber
therebetween whereby said sleeves are relatively expanded to
frictionally lock said bodies together.
21. In a well drilling tool as defined in claim 18, said fluid
pressure responsive means comprising a pair of sleeves, said bodies
having walls defining an annular space receiving said pair of
sleeves therebetween, one of said sleeves being fixed on one of
said bodies, the other of said sleeve and the other of said bodies
having opposing friction surfaces, said sleeves defining a pressure
chamber therebetween for expanding said other sleeve into
frictional locking engagement with said other body.
22. In a well drilling tool as defined in claim 18, said fluid
pressure responsive means comprising a pair of sleeves, said bodies
having walls defining an annular space receiving said pair of
sleeves therebetween, thread means fixing one of said sleeves on
one of said bodies, thread means mounting the other of said sleeves
on said one of said sleeves to prevent relative axial movement of
said sleeves while allowing relative circumferential movement of
said sleeves, said other of said sleeves and the other of said
bodies having opposing friction surfaces, said sleeves defining a
pressure chamber therebetween for expanding said other sleeve into
frictional locking engagement with said other body.
23. In a well drilling tool as defined in claim 22, said thread
means mounting the other of said sleeves on said one of said
sleeves comprising a buttress thread having abutting thread
surfaces normal to the axis of said sleeves and trailing flanks
forming said pressure chamber.
24. In a well drilling tool: a telescopic assembly comprising an
elongated inner body having means at one end for connection in a
drill string, an elongated outer body having means at one end for
connection in said drill string, the other ends of said bodies
being telescopically engaged, means interconnecting said bodies for
rotation as a unit and for telescopic movement, said bodies having
opposing shoulders limiting telescopic contraction, fluid pressure
responsive means between said bodies for holding said bodies
telescopically contracted with said shoulders tightly abutting, and
trigger means shiftably carried by said inner body for relieving
said fluid pressure responsive means upon movement of said trigger
means, said fluid pressure responsive means comprising means
defining a pressure chamber containing a body of fluid, piston
means having a first pressure responsive area exposed to the fluid
in said chamber and a second pressure responsive area exposed to
hydrostatic pressure, said bodies having opposing pressure
responsive areas exposed to the pressure of fluid in said chamber,
and said trigger means being operable to vent the fluid from said
chamber.
25. In a well drilling tool as defined in claim 24, said trigger
means and one of said bodies having companion sealing means
normally confining said fluid in said chamber, and said chamber
being vented upon movement of said trigger means.
26. In a well drilling tool as defined in claim 24, means defining
an atmospheric chamber, said piston means having a third pressure
responsive area exposed to said atmospheric chamber, and said
trigger means being operable to vent the fluid from said pressure
chamber to said atmospheric chamber.
27. In a well drilling tool as defined in claim 24, said bodies
having additional opposed shoulders spaced apart when said bodies
are telescopically contracted and adapted to produce a hammer blow
upon telescopic extension of said bodies.
28. In a well drilling tool as defined in claim 24, said fluid
pressure responsive means comprising means defining a pressure
chamber containing a body of fluid, piston means having a first
pressure responsive area exposed to the fluid in said chamber and a
second pressure responsive area exposed to hydrostatic pressure,
said bodies having opposing pressure responsive areas exposed to
the pressure of fluid in said chamber, and said trigger means being
operable to vent the fluid from said chamber, a sleeve removably
mounted in said chamber and slidably engaged by said piston, the
relationship between the first and second areas of said piston
means being determined by the radial thickness of said sleeve.
29. In a well drilling tool: a telescopic assembly comprising an
elongated inner body and an elongated outer body, means
interconnecting said bodies for rotation as a unit and for
telescopic movement, said bodies having opposing shoulders limiting
telescopic contraction, fluid pressure responsive means for holding
said bodies in telescopically contracted condition with said
shoulders tightly engaged, said fluid pressure responsive means
including means preventing all relative longitudinal movement
between said bodies from said contracted condition to retain said
shoulders tightly engaged, and trigger means operable by fluid
pressure in said inner body for releasing said fluid pressure
responsive means to permit disengagement between said shoulders and
telescopic extension of said bodies with respect to each other.
30. In a well drilling tool as defined in claim 29, said bodies
having additional opposed shoulders spaced apart when said bodies
are telescopically contracted and adapted to produce a hammer blow
upon telescopic extension of said bodies.
Description
In the drilling of wells, such as oil and/or gas wells, utilizing
rotary drilling tools, it sometimes becomes necessary or desireable
to be able to apply an impact or jarring action to the bit or to
the drill collars above the bit. Various jars or bumper subs are
available for such purposes, and, in general, they include an upper
body adapted to be made up in the drill collar string and a lower
companion body also adapted to be made up in the drill collar
string, the bodies having a torque transmitting splined connection
enabling relative longitudinal or telescopic movement of the
bodies. The bodies provide an anvil and a hammer for producing
hammer blows in the drill string above the bit.
During drilling operations such tools are subject to fatigue due to
the rotation and axial movements which occur, particularly in the
region of the usual shoulders. In the case of the typical jars
tension is applied to the drill string to cause the bleeding
through an orifice of internal fluid as the tension is increased,
the jar having a valve which opens when the tension reaches a given
force for sufficient time. Thus, jarring actions are time
consuming. Bumper sub devices are also available without the
hydraulic jar feature, but such tools are also subjected to stress
failures, since the shoulders are not held tightly together during
drilling operations.
The present invention provides a well drilling tool of the bumper
sub or jar type, including telescopic bodies adapted to be made up
in the drill collar string above the drill bit and locked up by
fluid pressure in a stressed condition approximately equal to the
prestress of the drill collars caused by torquing of the drill
collar joints, but the tool can be released, when desired, to
enable telescopic movement of the tool body sections. Release of
the tool body sections is accomplished by dropping a retrievable or
pump through plug in the drill string and operating a release
device.
In one form the invention involves a telescopic body the sections
of which are splined together for rotation and telescopic movement,
and the body sections being adapted to be shouldered up or
prestressed before installation in the drill collar string. While
prestressed or shouldered the body sections are hydraulically
locked together by an intermediate fluid pressure expansible
friction sleeve in which fluid is retained under pressure by means
releasable when a tripping plug actuates a trigger or shiftable
member to relieve pressure in the friction sleeve, thereby enabling
relative telescopic movement of the body sections, while the
splined connection maintains the torque transmitting capacity of
the tool.
In another form, the invention acts as a jar which is initially
prestressed by hydraulic pressure applied to a chamber and acting
on a differential piston which is also exposed to hydraulic
pressure in the drill string, the differential piston pressure
responsive area in the chamber being smaller than the differential
piston pressure responsive area exposed to pressure in the drill
string, whereby the tensioning or stressing force on the tool is
boosted by the drill string hydrostatic pressure. When the tool is
to be released to enable it to function as a jar, a tripping plug
is dropped in the drill string to seat on and actuate means for
equalizing the differential action and relieve the pressure
stressing the tool, while a jarring strain is maintained on the
drill string to effect an initial jarring action.
With drilling tools of the types referred to above, fatigue failure
is minimized by the prestressing of the tools, as the tools
effectively function merely to transmit torque and and locked
against relative telescopic movement.
This invention possesses many other advantages, and has other
purposes which may be made more clearly apparent from a
consideration of the forms in which it may be embodied. These forms
are shown in the drawings accompanying and forming part of the
present specification. They will now be described in detail, for
the purpose of illustrating the general principals of the
invention; but it is to be understood that such detailed
descriptions are not to be taken in a limiting sense, since the
scope of the invention is best defined by the appended claims.
Referring to the drawings:
FIG. 1 is a longitudinal section generally illustrating the
invention applied to a drill collar string of a well drilling
apparatus, with the drilling tool of the invention locked in a
prestressed telescopically contracted condition, and showing the
tripping plug traveling through the drill string;
FIG. 2 is a view corresponding to FIG. 1, but showing the tool
released;
FIG. 3 is a further view corresponding to FIG. 1, but showing the
tool telescopically extended;
FIGS. 4a through 4f, together, constitute a longitudinal section
showing, in detail, the structure of the apparatus of FIGS. 1 - 3
in the condition of FIG. 1, FIGS. 4b through 4f constituting
successive downward continuations of FIG. 4a;
FIG. 5 is a transverse section, as taken on the line 5--5 of FIG.
4a;
FIG. 6 is a transverse section, as taken on the line 6--6 of FIG.
4a;
FIG. 7 is a transverse section, as taken on the line 7--7 of FIG.
4b;
FIG. 7a is an enlarged fragmentary detail view in section of the
threaded connection embraced by the line 7a--7a of FIG. 4b;
FIG. 8 is a transverse section as taken on the line 8--8 of FIG.
4d;
FIGS. 9a through 9d, together, constitute a longitudinal section
through another form of the invention in a prestressed condition,
FIGS. 9b through 9d constituting successive downward continuations
of FIG. 9a;
FIG. 10 is a transverse section, as taken on the line 10--10 of
FIG. 9c; and
FIGS. 11a through 11d, together, constitute a longitudinal section
corresponding to FIGS. 9a through 9d, but with the tool in a
released condition for effecting a jarring action, FIGS. 11b
through 11d constituting successive downward continuations of FIG.
11a.
As seen in the drawings, referring first to FIGS. 1 - 3, a drilling
tool T is shwon as installed in a string of drill collars C which
are interposed between the lower end of a string of the usual drill
pipe P and the usual drill bit B, as is well known in the rotary
drilling of wells, such as oil and/or gas wells. The drill collars
C are employed to apply weight to the bit during drilling and are
heavy tubular bodies internally threaded at one end 10 and having
an externally threaded pin 11 at the other end to provide joints
between collars adapted to be tightly shouldered up. The drill
collars are made up in a number depending upon the weight desired
on the bit, the uppermost drill collar being connected to the drill
pipe P to be rotated thereby. The threaded connections between
drill collars are made up or shouldered up tightly to prevent
fatigue at the joints during drilling. In many drilling operations
it is desired to incorporate a drilling tool T in the drill collar
string in accordance with the invention, having an internally
threaded upper end 12 and an externally threaded lower pin 13
interconnecting the tool T with the upper and lower drill collars
C.
As generally illustrated in FIGS. 1 through 3, the tool T is an
elongated assembly comprising an upper and outer tubular body 14
and a lower and inner tubular body 15 having a splined connection
16 with the outer body 14, whereby the tool is telescopically
extensible and contractable and is capable of transmitting torque
for rotating the bit B. Within the outer body 14, the inner body
has a downwardly facing shoulder 17 opposing an upwardly facing
shoulder 18 internally of the body 14 for limiting telescopic
extension of the tool T, and at its lower end, the inner body 15
has an upwardly facing shoulder 19 opposed to the extreme lower
surface 20 of the outer body 14, which limit telescopic contraction
of the tool T. When desired, the tool T may be operated to enable
the upper body 14 to be reciprocated by raising and lowering the
drill pipe string P to effect a jarring action upon impacting of
the shoulders 17, 18 and 19, 20, but prior to such use of the tool,
it is desired that the tool effectively constitute a rigid body
corresponding to the drill collar C which will not fail or fatigue
during protracted drilling operations.
Accordingly, as will be more particularly described hereinafter,
means are provided whereby the body sections are locked with the
shoulders 19 and 20 held positively in prestressed engagement and
with the inner body 15 in tension, in the condition as shown in
FIG. 1. The means for locking up the body, as will also be more
fully described hereinafter, is responsive to a tripping plug 21
adapted to be dropped in the drill string and actuated by fluid
pressure to shift a trigger or sleeve 22 from the position of FIG.
1, in an upper location in the inner body 15, to the position of
FIG. 2, at which the trigger sleeve 22 is in a lower position, and
after movement of the trigger sleeve 22 the plug is pumped through
the sleeve. Shifting of the sleeve 22 to the position of FIG. 2
releases the means locking up the tool body so that the body
sections 14 and 15 are freed for relative longitudinal or
telescopic extension and contraction, as previously referred to,
the plug 21 moving downwardly into an enlarged cavity 23 in a bit
sub 24 and landing on a plug catcher 25, enabling unobstructed
circulation of drilling fluid through the bit B. Thereafter, the
tool T functions as a conventional bumper sub. The tripping plug,
if desired, may be of the wireline retrievable type instead of the
pump through type shown and described above.
Referring more particularly to FIGS. 4a through 4f and 5 through 8,
an illustrative tool T is shown, wherein the outer body 14
comprises an elongated tubular housing section 30 having at its
upper end a threaded connection 31 with a top sub 32 which has the
threaded receptacle 12 for receiving the threaded pin 11 of a drill
collar C. The threaded connection 31 is made up tight to cause
co-engagement between the opposing shoulders indicated at 33 of the
body section 30 and the top sub 32. At its lower end, the body
section 30 has the downwardly facing shoulder 20, previously
referred to. As best seen in FIG. 8, the body section 30 has
internal grooves 34 adapted to receive longitudinally extended ribs
35 on the inner body 15 to provide the splined connection 16.
The inner body section 15 of the tool T comprises a bottom sub 36
having the upwardly facing shoulder 19 previously referred to and
also having the threaded pin 13 for connecting the inner body 15 to
the drill collar C therebelow. Within the bottom sub 36 is a bore
37 threaded at 38 to receive the threaded lower end 39 of an
elongated tubular mandrel or inner body section 40. A side sealing
ring 41 is disposed between the mandrel end 39 and the wall of the
bore 37. Above the upper ends of the ribs 35 on the mandrel 40 is
an enlarged section 42 slidable in the outer housing or body
section 30 and having suitable sealing ring means 43 slidably end
sealingly engaging within the housing 30. Above the enlarged
mandrel section 42 the mandrel has a section 44 extending further
upwardly in inwardly spaced relation to the housing 30 to form an
annular space 45 adapted to receive the means 46 for locking the
tool up, with the shoulders 19 and 20 tightly engaged and the
mandrel 40 in tension to maintain engagement of the shoulders and
minimize fatigue which could occur during drilling in the absence
of such a prestressed condition.
This locking means comprises a hydraulic locking sleeve assembly
including inner and outer sleeve members 47 and 48 in the annular
space 45, and engaged with the housing 30 and mandrel section 44.
The sleeves 47 and 48 define a space 49 therebetween adapted to be
filled with a fluid, as will be later described. The inner sleeve
47 is internally threaded at 50 so as to be threadedly engaged
substantially throughout its length with a companion thread 51
formed externally on the mandrel 44.
The inner sleeve 47 has an external thread 47' extending along its
length and engageable with a companion internal thread 48' in the
outer sleeve 48. As best seen in FIG. 7a, the space 49 referred to
above is defined between the crests and roots of the threads 47'
and 48' and by the gap between the unloaded flanks of those
threads. The loaded flanks of these threads are straight so as to
not interfere with expansion of the outer sleeve 48 but so as to
securely connect the sleeves 47 and 48 against relative
longitudinal movement. The outer sleeve 48 and the inner sleeve 47
have a lower annular weld 52 formed as a bead between the lower
bevelled surfaces 47a and 48a of the sleeves 47 and 48, and at the
top of the sleeves 47 and 48 a similar weld 53 is formed between
the upper bevelled surfaces 47b and 48b of the sleeves 47 and 48,
this upper weld 53 constituting means for attaching to the locking
sleeve assembly a pair of tubes including a filled tube 54 and a
relief tube 55, the lower ends of which are welded in place and in
communication with the space 49 between the sleeves 47 and 48.
The tubes 54 and 55 extend upwardly in an annular space 56 defined
between a bore 57 in the top sub 32 and the outside wall of a
tubular mandrel extension 58. This mandrel extension has a threaded
lower end 59 engaged with an internal thread 60 on a neck portion
61 of the mandrel 44, a suitable side ring seal 62 being disposed
between the mandrel extension and the neck 61. At its upper end 63,
the mandrel extension 58 has another side ring seal 64 engaged in a
reduced bore 65 of the top sub 32. In the outer wall of the mandrel
extension 58 is a cavity 66, in which the upper end of the filler
tube 54 is disposed and crimped shut or welded after the filler
tube has been employed to fill the space 49 of the hydraulic
locking sleeve means 46 with fluid under pressure. The upper end of
the relief tube 55 is initially closed and at 67 extends laterally
through an opening 68 in the mandrel extension 58 so as to project
beyond the inside diameter of the mandrel extension and into an
annular groove 69 formed in the trigger sleeve 22 previously
referred to. The trigger sleeve 22 is shiftably disposed within the
mandrel extension 58 but is initially held in place in an upper
position by one or more shear screws 70 engaged between the mandrel
extension 58 and the trigger sleeve 22. Above and below the annular
groove 69 the trigger sleeve 22 carries upper sealing ring means 71
and lower sealing ring means 72 sealingly engaged within the
mandrel extension 58. Below the upper sealing ring means 71 the
mandrel extension has a vent opening 73 which is normally closed by
the seals described above. The end portion 67 of the relief tube 55
is adapted to be sheared by the sharp corner 74 provided on the
trigger sleeve 22 when the trigger sleeve is shifted downwardly, as
will be later described.
As seen in FIGS. 4a through 4c, the outer locking sleeve 48 has a
long cylindrical surface 75 engaged within the cylindrical inner
surface 76 of the housing or body section 30. Normally, in the
absence of pressure within the locking sleeve annulus 49 these
surfaces 75 and 76 would be relatively longitudinally shiftable,
but when the annulus 49 is pressurized via the filler tube 54, the
internal pressure acting outwardly on the outer locking sleeve 48
expands the latter outwardly so that the surfaces 75 and 76 on the
locking sleeve 48 and in the housing 30, respectively, are forced
into tight frictional co-engagement, thereby locking the elements
against longitudinal movement, and since the inner locking sleeve
47 is connected to the mandrel 44, it is apparent that when the
annulus 49 is pressurized the inner and outer bodies 14 and 15 of
the tool are locked against telescopic movement. To enhance the
coefficient of friction between the surfaces 75 and 76, the surface
75, prior to assembly, may be dusted with grit, say 600 mesh
carburundum.
In the use of the tool T, prior to its installation in the drill
collar string, a suitable tool (not shown) of the type generally
corresponding to a wheel or bearing puller, that is, a push-pull
tool, can be connected to the inner and outer bodies 14 and 15 of
the tool T to tension the inner body and push on the outer body,
thereby locking and prestressing the abutting shoulders 19 and 20
as previously described. For example, with the top sub 14 and the
mandrel extension 58 removed, such a pushpull tool can be connected
to the thread 60 of the mandrel neck 61 to pull on the latter while
pushing on the upper end of the housing 30. With the tool bodies
thus prestressed the locking sleeve annulus 49 can be filled and
pressurized to lock the tool bodies together, and escape of the
pressurizing fluid through the filler tube may be prevented by
crimping or by use of a backflow preventing valve. The mandrel
extension 58 is then assembled on the mandrel 44, the tubes 54 and
55 positioned as shown in FIG. 4a, and then the top sub 32 can be
applied to the housing 30 to complete the assembly of the tool. The
tool T is then ready for installation in the drill collar string
and for use in the drilling of a well.
When it is desired to release the tool for telescopic movement of
the inner and outer bodies to effect a jarring action as described
above, the tripping plug 21 traveling downwardly through the drill
string initially seats upon the upper inner seat 22a on the trigger
sleeve 22, thereby preventing fluid flow through the trigger
sleeve. When pressure in the drill string is increased the plug
will force the trigger sleeve 22 downwardly shearing the shear
screw 70 and the trigger sleeve 22 will move to its lower position
engaged with the seat 22b on the mandrel 44 below the mandrel
extension 58. As the trigger sleeve moves downwardly it will shear
the end from the relief tube 55, thereby relieving the fluid
pressure from the annulus 49 of the hydraulic locking sleeve means
46. The tool is then free for telescopic motion.
When the trigger sleeve 22 engages the stop shoulder 22b, the
tripping plug 21 is pumped through the sleeve and lands on the plug
catcher 25 previously referred to. While the plug catcher may be a
sleeve, the plug catcher, as seen in FIG. 4f, is incorporated in a
float valve 80 having a tubular body 81 held in place in the bore
82 of the bit sub 24 by the threaded pin 83 of the bit B.
Reciprocable in a spider 84 in the valve body 81 is the stem 85 of
a valve head 86 which is normally biased into engagement with the
seat 88 by a spring 87. As the drill string is being lowered into
the well, this float valve is held closed by the pressure of fluid
in the well, but when drilling fluid is being circulated the valve
is open.
Referring to FIGS. 9a through 9d a modified tool T is shown in the
form of a hydraulic jar which is initially locked up, but which is
released by a tripping plug to allow the tool to be telescopically
extended to provide the jarring action. In FIGS. 11a through 11d,
the tool is shown in the released, jarring condition.
In this form, the outer body comprises an elongated, tubular upper
body section or housing 100 telescopically engaged with the upper,
inner body section 101, the body sections 100 and 101 having
companion ribs and grooves providing a splined connection at 102.
At its lower end, the outer body or housing section 100 is threaded
at 103 to a cylinder head 104 having a bore 105 in which a
cylindrical section 106 of the inner body section 101 is slidable
and sealed by a side ring seal 107. Below the cylinder head 104 is
a lower body section 108 threaded on a skirt or anvil portion 109
of the cylinder head 104. At the lower end of the anvil portion 109
is a shoulder 110 which faces downwardly and which is adapted to be
impacted by a hammer 111 carried by the inner body 101. This hammer
111 is threaded onto the inner body 101 at 112 and locked thereon
by a pin 113. A side ring seal 114 forms a seal between the body
101 and the hammer 111.
Below the body 101, the hammer 111 has an elongated skirt 115
extending downwardly and disposed in an annular space 116 defined
between the inner cylindrical wall of the lower body section 108
and an elongated tubular trigger sleeve 117. This trigger sleeve
117 has an upper sealing ring 118 sealingly and slideably engaged
with the skirt 115, and when in its normal or upper position, as
seen in FIG. 9c and 9d, the trigger sleeve has an intermediate
sealing shoulder 119 engaged with the opposed sealing bevelled
surface 120 of the skirt 115. An outer ring seal 145a is provided
between the housing 108 and the lower end of the skirt 115. The
sealing surfaces 119, 120, when engaged separate the annular space
116 from a lower atomospheric chamber 121 defined between the lower
body 108, the trigger sleeve 117, and the upper end of an annular
differential piston 122. This piston 122 has an inner sealing ring
123 slidably engaging the cylindrical wall 124 of the trigger
sleeve 117, and an outer sealing ring 125 slidably engaging the
inner cylindrical wall 126 of a ratio or booster sleeve 127 which
extends into the atmospheric chamber 121, and which has a lower
flanged section 128 provided with a seal ring 129 engaged with the
cylindrical wall 130 of the housing section 108, the lower end of
the flanged section 128 of the booster sleeve being disposed in an
annular space 131 defined between the cylindrical wall 130 of a
reduced mid-section 132 of the differential piston 122. At its
lower end, the piston 122 is provided with outer sealing ring means
133 and inner sealing ring means 134, respectively, slidably
engaging the cylindrical wall 130 of the housing section 108 and a
reduced cylindrical wall portion 135 of the trigger sleeve 117. The
lower end of the differential piston 122 is exposed to the pressure
of fluid in the drill string through a bore 136 in the lower
connector sub 137 to which the housing section 108 is connected at
138.
Passage means are provided in the trigger sleeve 117 whereby oil or
other fluid under pressure can fill the annular space 116 in the
housing 108. More particularly, the trigger sleeve has an elongated
passage 139 having a filler opening 140, the passage 139 extending
longitudinally in the trigger sleeve and communicating through a
lower radial port 141 with the annular space 142 defined between
the trigger sleeve 117 and the mid-section 132 of the piston 122,
the piston also having a radial port 143 through which fluid finds
access to the outer annular space 131, previously referred to.
Adjacent to its upper end, the passageway 139 communicates through
another radial port 144 with the annular space 116 in the body
section 108, the lower end of the hammer skirt having a radial
opening 145 to allow the fluid to fill the annulus 116.
The trigger sleeve 117 is normally held in an upper position with
respect to the hammer skirt 115, with the sealing surfaces 119 and
120 in engagement and separating the pressurized fluid in the
annulus 116 and acting on the piston 122 in the annular spaces 131
and 142 from the atmospheric pressure in the chamber 121. A coiled
compression spring 146 seats on a shoulder 147 in the connector sub
137 and acts upwardly on a shoulder 148 of the trigger sleeve
117.
Pressure fluid applied to the annulus 116 acts upwardly on the
pressure responsive area D of the anvil 109 and downwardly on the
pressure responsive area E of the hammer 111 causing telescopic
contraction of the inner and outer bodies of the tool, thereby
axially locking or prestressing the tool and maintaining the tight
engagement between the upper shoulder or surface 100a of the outer
body 100 and the downwardly facing surface or shoulder 101a of the
outer body 101. During drilling with the tool, the pressure of
drilling fluid in the drill string, that is, the hydrostatic
pressure of the drilling fluid column, is applied to the annular
area F of the differential piston 122 which in turn, effects an
intensified pressurization of the oil within the annulus 116,
depending upon the difference between the annular area F and the
net effective area of the differential piston in the annular space
131 designated area G and in the annulus 142 and designated area H.
Since the area F of the piston is substantially greater than the
sum of the areas G and H, the internal pressure of oil acting on
the areas D and E, causing the tool to be locked up tightly, is
greatly intensified so that no working of the tool can result from
the drilling operations and fatigue is prevented. The intensity of
the pressure can be modified by changing the dimensions of the
sleeve 127 and the piston 122 so that the effective area G can be
increased or decreased. In other words, the substitution of a
booster sleeve and piston of different diameters will effect a
difference in the intensification of the hydrostatic pressure of
drilling fluid.
When it is desired to effect a jarring action, the pipe string is
tensioned and a tripping plug 150, of the wireline retrievable
type, is dropped through the drill pipe and will come to rest on a
bevelled seat 151 within the trigger sleeve 117. The illustrated
tripping plug 150 is shown as comprising an elongated body 152
having a retrieving neck 153 at its upper end and a valve ring 154
normally biased upwardly into abutting engagement with the base
flange 155 of the retrieving neck 153 by a coiled spring 156. When
this tripping plug is on the seat 151 drilling fluid pressure can
be applied to cause the trigger sleeve 117 to be forced downwardly,
thus disengaging the sealing surfaces 119 and 120, as seen in FIG.
11c. When the pressurized fluid in the annulus 116 is dumped into
the atmospheric chamber 121, instantaneously, the pressure acting
on hammer and anvil areas A and B is relieved so that in response
to the tension in the drill string the inner body 101 will move
rapidly upwardly with respect to the outer body 100 and the hammer
111 will strike a blow against the anvil 109 as seen in FIG.
116.
As the trigger sleeve 117 moves downwardly to the position of FIG.
11d, the lower end surface 150a of the tripping plug 150 shoulders
on the shoulder 147 of the outer body or connector sub 137. Fluid
pressure will then shift the valve ring 154 downwardly overcoming
the spring 156 and opening a flow path, as shown by the arrows in
FIG. 11d, between the valve ring 154 and the flange 155 and through
slots 152a extending longitudinally of the plug 150, to enable the
circulation of fluid.
After tripping, the tool will continue to act as a hydraulic jar
instead of merely as a bumper sub. This action is accomplished by
lowering the drill pipe to close the tool and shutting off the pump
which will permit spring 146 to return the trigger sleeve 117 to
sealing engagement with skirt 120. At this time, the atmospheric
chamber 121 is filled with oil at the same pressure as hydrostatic
pressure and therefore there is no longer a compressive force
between shoulders 110a and 101a. However, when the drill pipe is
again tensioned, the oil in the annular space 116 cannot escape and
will be compressed to whatever pressure is required to resist
relative movement of the inner and outer members. As pressure
increases, it will act over areas G and H tending to return
differential piston 122 to its original position. The hydrostatic
pressure trapped in the hydrostatic chamber will drop off
proportional to the force developed on differential piston 122
until, if enough pressure is developed in annular space 116, it
will fall to zero as this pressure acting on areas G and H
overcomes the force acting upward due to hydrostatic pressure
acting on area F. The tool would then be essentially in the same
condition it was in originally and can be released to strike a
jarring blow by again applying enough pump pressure to move trigger
117 downward to relieve the pressure in 116.
* * * * *