Note: Descriptions are shown in the official language in which they were submitted.
5 7 6
ROTARY BLOWOUT PREVENTER ADAPTABLE FOR USE
WITH BOTH KELLY AND OVERI~EAD DRIVE MECHANISMS
The present invention relates to rotary blowout
preventers having internal sleeves through which a drill
pipe or kelly is received and more particularly relates to
such rotary blowout preventers havillg hydraulics to urge the
sleeve in sealing abutment with the drill pipe or kelly
received therein. In even greater particularity the present
invention relates to rotary blowout preventers having means
embedded within the sleeve for gripping the pipe or kelly to
facilitate concomitant rotation of the sleeve therewith.
Back~round of the Invention
Rotary blowout preventers are commonly used in the
petroleum industry to isolate wellbore fluids while drilling
procedures are being conducted. Typically a casing spool
having a discharge portal thereon is provided for the
wellbore fluid to exit through. The rotary blowout
preventer is connected to and supported on the casing spool
and receives a drill string therethrough which is rotated to
facilitate drilling of the wellbore.
One method for rotating the drill string is to extend
an elongated, cross-sectionally polygonal kelly through an
engine driven rotary table housed in the drill deck. The
table has a polygonal bushing orifice therein through which
the kelly is received. The kelly is connected to the
uppermost joint of drill pipe forming the drill string to
1-
21~8576
rotate the same under the rotating influence of the rotary
table. Rotary blowout preventers are provided that can
sealingly engage the kelly while it rotates. One such
blowout preventer is disclosed in U.S. Patent No. 3,492,007
issued to Jones on January 27, 1970. Jones provides a
hexagonal split kelly bushing for gripping a hexagonal
kelly. The kelly bushing is connected to a rotary housing
in the blowout preventer to secure the housing to the kelly
for concomitant rotation therewith. The rotary housing
carries an elastomeric packer assembly therein that
sealingly engages the kelly. The packer assembly rotates
with the rotary housing and is not subjected to rotary
forces from the kelly because of the hexagonal kelly
bushing's connection to the rotary housing. Such connection
promotes concomitant rotation of both the rotary housing and
the packer assembly with the kelly. Without connection to
the kelly bushing, the kelly would rotate relative to the
packer assembly and would wear or otherwise damage the
elastomeric packer, requiring replacement thereof.
~0 A second method for rotating the drill string is to use
an overhead drive connected to an uppermost section of drill
pipe for rotating the same. No kelly is used so one section
of the cylindrical drill pipe is always positioned within
the rotary blowout preventer during rotation of the drill
~5 string. The cylindrical nature of drill pipe presents a
problem for conventional blowout preventers since a rigid
21~8576
bushing that will engage the pipe's cylindrical surface and
still permit the longitudinal movement of the drill pipe
through the bushing is unavailable in the industry.
Furthermore, each drill pipe has an expanded diameter collar
on one end to facilitate connection thereof with the next
adjacent drill pipe. Longitudinal movement of the drill
pipe through a rigid bushing would be prohibited by the
expanded diameter collar.
As previously mentioned, direct contact of the
elastomeric packer assembly with a rotating kelly or drill
pipe will result in rapid wear or even spontaneous
disintegration of the packer. As packers such as the inner
packer shown in Jones are relatively expensive and time
consuming to replace, direct contact thereof with the drill
pipe is not advised.
Additionally, the seals and bearings commonly found in
rotary blowout preventers are particularly susceptible to
wear from heat generated by the temperature of wellbore
fluids and the friction commonly occurring with such rotary
bearings and seals. Foreign particulate matter suspended in
the rotary blowout preventer is also a common element
promoting the wear of such seals and bearings. Once the
seals and/or bearings have been worn, they must be replaced.
As shown in Jones, the seals and bearings are commonly
seated deep within the outer casing of the blowout preventer
and require substantial effort and time to replace.
2148576
Summary of the Invention
It is the principal object of the present invention to
provide a rotary blowout preventer that will sealingly
engage either a rotating kelly or drill pipe for concomitant
rotation therewith without suffering wear or other damage to
the packer elements seated therein.
In support of the principal object, another object of
the present invention is to provide an easily replaceable
elastomeric sleeve that is detachably seated within the
rotary housing intermediate the drill pipe and the packer
assembly for isolating the packer assembly from the drill
pipe.
Yet another object of the present invention is to
provide an elastomeric sleeve as set forth above having
rigid grippers seated within an inner surface thereof for
gripping the drill pipe for concomitant rotation therewith
to thereby reduce the wear on the detachable sleeve.
Still another object of the present invention is to
provide a blowout preventer, having all the aforesaid
characteristics, that removes particulate matter from the
bearing and seal assemblies.
A further object of the present invention is to provide
a rotary blowout preventer that cools the bearing and seal
assemblies.
These and other objects and advantages of my invention
are accomplished through the use of a rotary blowout
2148576
preventer having an outer houslng and a rotary housing
rotably mounted within the outer housing. The rotary
housing carries an annular elastomeric packer assembly and
is supported in the outer housing by bearings. Seals are
provided at the upper and lower ends of the outer and rotary
housing to prevent wellbore fluids from migrating therepast.
A sleeve assembly is detachably connected to a rim
portion of the rotary housing and depends therefrom within
the rotary housing adjacent the packer assembly. The sleeve
assembly includes an annular adapter having a suspension
flange supported on the rim portion of the rotary housing.
The annular adapter has a plurality of splines thereon which
are inserted through and below a plurality of notches
defined in the rim. The splines are rotated below the rim
to lock the adapter thereto. A lock pin extends through the
suspension flange and is received within the rim to secure
the adapter in non-rotating relation thereto. A tubular
elastomeric sleeve is detachably connected to the annular
adapter and depends therefrom adjacent the packer assembly.
A rigid securing ring is connected to an upper margin of the
elastomeric sleeve and is detachably connected to the
adapter by bolts. A rigid support ring is connected to a
lower margin of the elastomeric sleeve to maintain the
circular integrity thereof.
z5 Rigid gripper elements constructed of hardened epoxy
resin or steel are received within the elastomeric sleeve
2148~75
and extend inwardly therefrom to present a flat gripping
face flush with the inner surface of the sleeve. The
grippers have a greater coefficient of friction than the
elastomeric nitrile rubber from which the sleeve is
constructed and are less susceptible to damage due to their
rigid construction. The grippers engage a drill pipe
received within the rotary blowout preventer when the packer
assembly and sleeve are urged inwardly by hydraulic fluid
circulated through the outer housing. The grippers grasp
the drill pipe to facilitate concomitant rotary movement of
the-sleeve assembly, rotary housing and packer assembly
therewith when the drill pipe is rotated during drilling
operations.
The packer assembly and sleeve are urged inwardly by a
pair of motor driven hydraulic pumps which circulate
hydraulic fluid from a reservoir and through the outer
housing. Orifices in the rotary housing permit the
hydraulic fluid to pass behind the packer assembly and urge
the packer assembly and sleeve inwardly toward the drill
pipe. The circulated hydraulic fluid provides the necessary
pressure to actuate the packer assembly and also removes
foreign particulate matter from the bearings and seals. A
heat exchanger is connected to and communicates with the
reservoir and the pumps for cooling the hydraulic fluid and
thereby reduces the temperature of the bearings and seals
the fluid comes in contact with. By maintaining a lower
2148576
temperature in the blowout preventer, the working life of
the bearings, seals and packer assembly will be
significantly extended. The pressure inside the outer
housing and within the wellbore is monitored by transducers
which iteratively transfer this information to a computer.
The computer is electronically connected to the pump's
motors and, responsive to the data received from the
transducers, iteratively signals the pumps to provide a
sufficient pressure within the outer housing and on the
packer assembly to maintain a predetermined pressure
differential above the pressure occurring in the wellbore.
Manual override apparatus is provided to allow an operator
to disengage the computer means and remotely and manually
operate the pumps.
Brief Description of the Drawings
Apparatus embodying features of my invention are
depicted in the accompanying drawings which form a portion
of this disclosure and wherein:
FIG. 1 is a sectional view of the present invention
connected to and supported on a casing spool;
FIG.2 is an enlarged sectional view of the present
invention with the outer housing generally shown in phantom
lines:
FIG. 3 is an exploded perspective view, partially in
section, of a detachable sleeve assembly and rim;
214857~
FIG. 4 is a partially broken plan view of the present
invention in an unlocked position;
FIG. 5 is a plan view of the present invention in a
locked position.
FIG. 6 is a schematic view of the present invention;
and
FIG. 7 is an enlarged detailed sectional view of the
elastomeric sleeve with a singular gripper element shown in
elevation.
~ Description of the Preferred Embodiment
As shown in FIGS. 1 and 2, the present invention is a
rotary blowout preventer including an outer housing 11
having a bottom body flange 12 typically connected to and in
communication with a casing spool 13. The outer housing 11
further includes a cylindrical main body 14 connected to the
bottom body flange 12 and a top body flange 16 connected to
the main body 14 opposite the bottom body flange 12. A
rotary housing 17 is rotably connected to and encased within
the outer housing 11 and includes a rotary housing base 18
rotably supported on the bottom body flange 12 by a bearing
assembly 19 connected to the rotary housing base 18. The
rotary housing base 18 is received within a bore 21, which
extends through the bottom body flange 12 and extends in
coaxial relation thereto to communicate with the casing
spool 13. The rotary housing base 18 is sealingly engaged
within the bore 21 by a seal assembly 22a. The rotary
- 21485 76
housing 17 further includes an enlarged diameter rotary
packer housing 23 connected to and integral with the rotary
housing base 18 for rotary movement therewith about a
vertical axis. A rotary housing cover 24 is connected to
the rotary packer housing 23 opposite the rotary housing
base lB. The rotary housing cover 24 extends within a bore
26 defined in the top body flange 16 and is laterally
engaged therein by a bearing assembly 27 connected thereto.
The rotary housing cover 24 is sealingly engaged within the
bore 26 by a seal assembly 22b.
As shown in FIGS. 1 and 2, a drill pipe 28 is typically
received within the rotary housing 17 and is rotated about
its longitudinal axis by an overhead drive mechanism (not
shown). To isolate wellbore fluids (not shown) below the
rotary packer housing 23, packer assembly 31 is provided to
selectively engage the drill pipe 28 in sealing abutment
therewith. The packer assembly 31 includes an elastomeric
outer packer 32 seated within the rotary packer housing 23
and cooperatively held in proximate relation with an inner
surface 33 thereof by a retainer ring 34, the rotary packer
housing 23 and the rotary housing cover 24. The retainer
ring 34 defines a series of orifices 36 spaced around the
circumference thereof that are aligned with orifices 37
extending through the rotary packer housing 23. The
orifices 36 and 37 permit hydraulic fluid (not shown) that
is selectively injected within the outer housing to compress
2148576
the outer packer inwardly. An elastomeric inner packer 38
is concentrically positioned inwardly from the outer packer
32 and is thus urged inwardly by the motion of the outer
packer 32.
As shown in FIGS. 1,2 and 3-5, a quick change
elastomeric sleeve assembly 39 is detachably connected to an
upper rim 41 of the rotary housing cover 24 and is suspended
within the rotary housing 17 inwardly of the inner packer
38. The rim 41 defines a plurality of spaced apart inwardly
opening notches 42. An annular packer sleeve adapter 43 is
received within and is detachably connected to the rotary
housing cover 24 for concomitant rotation therewith. The
annular adapter 43 includes a substantially tubular body 44
having a suspension flange 46 integrally connected to and
extending outwardly from an upper margin thereof. The
suspension flange 46 rests on the rim 41 when the adapter 43
is received within the rotary housing cover 2~ and supports
the body 44 therein. A plurality of splines 47 are
integrally and externally connected to body 44 in spaced
relation to the rim 41 and in cooperative relation to the
notches 42. The rim 41 and splines 47 cooperate to lock the
adapter 17 within the rotary housing cover 24.
When the adapter 43 is received within the rotary
housing cover 24, the splines 47 are received within and
pass below the notches 42 to an unlocked position shown in
FIG. 5. The suspension flange 46 rests on the rim 41 and
21485 7~
supports the splines 47 just below the notches 42. As shown
in FIG. 6, the annular packer sleeve adapter 43 and splines
47 connected thereto are manually rotated a predetermined
angular distance to offset the splines 47 from the notches
42 and thereby place the adapter 43 and the splines 42 in an
axially locked position.
As shown in FIG. 3, an aperture 48 extends through the
suspension flange 46 for receiving therethrough a lock pin
49 which is received in a hole 51 defined in rim 41. As
shown in FIGS. 1 and 2, the pin 49 secures the suspension
flange 46 to the rim 41 and secures the adapter 43 in non-
rotating relation to the rotary housing cover 24. ~s shown
in FIGS. 5 and 6, a pin 52 is integrally connected to the
rim 41 in diametrically opposed relation to hole 24 and
extends upwardly therefrom within a curved slot 53
concentrically defined in the suspension flange 46. The pin
52 and slot 53 indicate when the adapter is in either a
locked or unlocked position and further assist in aligning
the aperture 48 with hole 51. When the splines 47 are
inserted through the notches 42, with the slot 53 positioned
above the pin 52, the pin 52 will be received within the
slot 53 at a first predetermined end 54 thereof and will
thereby indicate that the adapter 43 is in the unlocked
position. Rotation of the adapter 43 to urge the opposite
or second predetermined end 56 of the slot 53 in abutment
with the pin 52 will urge the adapter 43 into the locked
21~8576
position and will align the aperture 48 with hole 51. The
lock pin 49 can then be inserted in hole 51 and engaged
therein by rotating the lock pin 49, thus to securing the
adapter 43 in the locked position.
An elastomeric sleeve 57, shown in FIGS. 1, 2 and 3, is
detachably and reattachably connected to a lower end 58 of
the annular adapter 43 and depends therefrom within the
rotary housing 17. The sleeve 57 is connected at an upper
end to a rigid securing ring 59 which is detachably
connected to a lower end of the adapter 43 by bolts 61
The sleeve 57 engages the drill pipe 28 extending
therethrough and is selectively urged inwardly in sealing
contact with the pipe 28 by the inward compression of inner
packer 38. A rigid support ring 62 is connected to a lower
end of the elastomeric sleeve 57 and prevents the upward
movement of the drill pipe from folding the sleeve inwardly
within itself.
The outer packer 32, the inner packer 38 and
elastomeric sleeve 57 are selectively urged inwardly by
circulated hydraulic fluid (not specifically shown)
introduced within the outer housing 11 and injected through
orifices 36 and 37. As shown in FIG. 6, the hydraulic fluid
is circulated from a reservoir 63 located outside the outer
housing 11. The hydraulic fluid is circulated by a pair of
piston pumps 64 connected to the reservoir 63 and driven by
motors 66. Hydraulic fluid discharged from pumps 64 passes
2148576
through a discharge filter 67 connected thereto which is
connected to and communicates with the outer housing 11
through input line 68 . ~s shown in FIGS. 1 and 2, hydraulic
fluid flowing through input line 68 is introduced within an
annulus 69 defined intermediate the outer housing 11 and
rotary housing 17. Fluid entering annulus 69 passes through
orifices 36 and 37 and, as the pressure generated by pumps
64 is selectively increased, selectively compresses the
outer packer 32 inwardly to urge the inner packer 38 and
elastomeric sleeve 57 toward the drill pipe 28. The
hydraulic fluid entering the annulus 69 serves to maintain a
selected pressure on the packer assembly 31 and cools the
seal assemblies 22a and 22b thus extending the longevity of
their use by reducing the effects of the intense heat
typically generated by their contact with rotary housing 17.
The circulated hydraulic fluid also cools the elastomeric
outer and inner packers 32 and 38. Furthermore, foreign
particulate matter, inadvertently introduced within the
annulus, that naturally contributes to the wear of the seal
or bearing assemblies is removed by the circulation of the
fluid. Hydraulic fluid entering the annulus 69 exits the
outer housing 11 through output line 71 which is connected
to and communicates with the outer housing 11 in diametric
relation to the input line 68 . The output line 69 is
connected to and communicates with a failsafe valve 72 which
is connected to and communicates with a return filter 73.
- 2148~i7~
The discharge and return filters 67 and 73 remove
particulate matter from the hydraulic fluid to reduce the
wear on those components of the invention contacted thereby.
The return filter 73 is connected to and communicates with a
heat exchanger 74 which cools the hydraulic fluid passing
therethrough to a selected temperature. The heat exchanger
74 is connected to and communicates with the reservoir 63 to
complete the circulation of the hydraulic fluid. A system
panel 76 is provided to monitor and control the pressure in
the annulus 69. The panel 76 is electronically connected to
first and second transducers 77 and 78 which are operatively
connected to the input line 68 and casing line 13a,
respectively, to monitor the pressure in the annulus 69 and
casing spool 13. The transducers 77 and 78 recurrently send
an electronic signal to the panel 76 continually indicating
the pressures in the annulus 69 and casing spool 13. The
panel 76 has a computer 79 for analyzing these signals and
automatically emitting a control signal to the pumps 64.
The control signal activates the pumps to maintain pressures
in the annulus 69 that are a selected predetermined pressure
differential above the pressure recorded in the casing spool
13. Note that pressures recorded in casing line 13a and
casing spool 13 are directly indicative of pressures within
a wellbore (not shown) therebelow. A deactivator switch 81
is connected to the computer means 79 and a manual control
82 for selectively disengaging the computer means 79 and
14
214~576
electronically connecting the manual control 82 to the pumps
64 and motors 66 for remote but manual operation thereof.
The failsafe valve 72 is electronically connected to the
control panel 76 and, responsive to a total loss of power,
will actuate to close the output line 71 thereby containing
the pressure existing at the annulus 69 just prior to the
power loss. Such pre-power loss pressure is maintained at
the pumps 64 by pump outlet check valves 83 commonly
connected thereto.
In operation, one of a plurality of drill pipes 28,
connected in string, is received within the rotary housing
17. During drilling operations, the drill pipes 28
including the one received in the rotary housing 17 are
rotated by an overhead drive mechanism (not shown). The
pumps 64 are activated to provide continuous pressurized and
circulated hydraulic fluid at the annulus 69 and thereby
hydraulically actuate the outer and inner packers 32 and 38
inwardly to urge the elastomeric sleeve 57 in sealed
abutment with the drill pipe 28 received therein. The
frictional contact of the sleeve's 57 cylindrical inner
surface 84 with the rotating drill pipe 28 causes the sleeve
57, adapter 43, rotary housing 17 and packer assembly 31 to
rotate concomitantly therewith. If the elastomeric sleeve
57 should become worn or damaged, it can be easily
disengaged from the rotary housing 17 and adapter 43 and
replaced with a new sleeve of like configuration. Minimal
214~5~G
downtime is required to replace the sleeve 57 which is
relatively inexpensive in relation to the cost of replacing
an inner packer 38. The sleeve 57 protects the inner packer
38 from wear, thereby eliminating the cost of continual
replacement thereof.
Concomitant rotation of the sleeve 57 with drill pipe
Z8 is specifically facilitated by a plurality of grippers
85, seated within the elastomeric sleeve 57, as shown in
FIGS. 1, 2, 3 and 7. The grippers 85 have outer faces 86
that extend flush with the inner surface 84 of the sleeve to
maintain a continuous seal across the elastomeric sleeve 57
when the inner surface 84 is urged into contact with the
drill pipe.
The grippers 85 are constructed of semi-rigid materials
such as epoxy resin intermixed with selected granular
materials such as sand or particles of carbide steel.
Grippers 85 formed entirely from carbide steel or any other
material having a coefficient of friction sufficient to grip
the drill pipe 28 for concomitant rotation therewith and
having sufficient hardness to resist destruction by the
movement of the drill pipe 28 are also contemplated by the
present invention.
As is shown in FIG. 7, the grippers 85 are integrally
seated within the elastomeric sleeve 57. Each gripper 85
includes a cylindrical enlarged portion 91 and an elongated
portion 92 integrally connected to the enlarged portion 91.
16
21~85 76
The grippers 85 are seated within the elastomeric sleeve 57
by pouring the elastomeric polymer in liquid form into a
mold (not shown) and around the grippers 85 spaced therein.
The elastomeric sleeve 57 bonds with the grippers 85 and
thus secures the grippers therein. Shoulders 93 formed by
the sleeve 57 inwardly of the enlarged diameter portion
further obstruct the inadvertent removal of the grippers
from the sleeve 57.
One skilled in the art will recognize that the shape of
the grippers 85 is not limited to the above description.
Grippers having many shapes and sizes may be utilized. The
outer faces 86 are shown in FIG. 7 to be flat; however, one
skilled in the art will recognize that the outer faces 86
may be curved to more accurately conform to the cylindrical
inner surface 84 or may be serrated to better grip the drill
pipe 28.
In operation, the drill pipe 28 is received within said
sleeve 57 for sliding longitudinal movement therethrough.
When the pumps 64 are actuated, the fluid pumped thereby
2~ will urge the inner surface 84 and outer faces 86 in sealing
contact with the drill pipe 28. The grippers 85, due to
their epoxy and granular construction, are more rigid than
the elastomeric sleeve 57 and exert a greater frictional
force on the drill pipe 28 when urged in contact therewith
by the hydraulic pumps 64. The grippers 85, under the
compressive influence of the pumps 64, frictionally engage
2148~76
the drill pipe 28 and secure the packer assembly 31 thereto
for concomitant rotary motion therewith. Such gripping
action prevents slippage of the packer assembly 31 and
reduces wear on the sleeve 57. The grippers 85 do not,
however, grasp the drill pipe 28 so tightly as to prevent
the longitudinal sliding motion thereof through the sleeve
57. The downward force exerted by the weight of the drill
pipe as well as the forces necessary to lift the drill pipe
28 will easily overcome the frictional gripping force
exerted by the grippers 85. From the foregoing, it should
be clear the present apparatus represents a substantial
improvement over the prior art.
While I have shown my invention in one form, it will be
obvious to those skilled in the art that it is not so
limited but is susceptible of various changes and
modifications without departing from the spirit thereof.
