U.S. patent number 3,791,442 [Application Number 05/184,444] was granted by the patent office on 1974-02-12 for coupling means for a riser string run from a floating vessel to a subsea well.
This patent grant is currently assigned to Regan Forge and Engineering Company. Invention is credited to Bruce J. Watkins.
United States Patent |
3,791,442 |
Watkins |
February 12, 1974 |
COUPLING MEANS FOR A RISER STRING RUN FROM A FLOATING VESSEL TO A
SUBSEA WELL
Abstract
A coupling means connects a riser string of tubing to a floating
vessel over a subsea well to which the string is run by a support
member, which in one version is a housing mounted beneath the
rotary table on the vessel with a tubing hanger support means
provided in the housing, and in another version is a support ring
mounted in the sea beneath the vessel by constant tension cables
run from the vessel. A string of tubing is run through the bore of
the rotary table and a central bore through the support member to
the subsea well. The tubing hanger supporting the riser string is
also run through the table bore and is landed in the support member
positioned beneath the table. The support member also in one
version has a fluid line coupling means provided integrally thereof
for automatically connecting the interior of the riser string of
tubing to a vessel associated fluid line upon the landing of the
tubing string in the support member. The support member, in the
latter version, is also provided with a diverter insert, a
blowout-preventer insert, and a packer insert to provide radial
passages and a collector passage within the support member to
conduct well fluids from a space between an operating string and
the surrounding riser string while closing the upper end of the
support member to prevent the escape of fluids therefrom.
Inventors: |
Watkins; Bruce J. (Palos Verdes
Estates, CA) |
Assignee: |
Regan Forge and Engineering
Company (San Pedro, CA)
|
Family
ID: |
22676888 |
Appl.
No.: |
05/184,444 |
Filed: |
September 28, 1971 |
Current U.S.
Class: |
166/352; 166/359;
166/355; 285/18 |
Current CPC
Class: |
E21B
17/01 (20130101); E21B 19/006 (20130101) |
Current International
Class: |
E21B
17/01 (20060101); E21B 19/00 (20060101); E21B
17/00 (20060101); E21b 007/12 () |
Field of
Search: |
;175/5,7,8,9,10,214
;166/5,6,75,315,78,81,82,88,84 ;277/31 ;114/.5
;285/140,142,143 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Champion; Marvin A.
Assistant Examiner: Favreau; Richard E.
Claims
I claim:
1. A coupling means for coupling a riser string of tubing to a
floating vessel over a subsea well to which said string is run,
said vessel having a rotary table mounted upon a support structure
on said vessel and having a table bore therethrough positioned over
a path to said well, said coupling means comprising:
a support member having a bore for the passage of tubing
therethrough and means for supporting a tubing hanger landed in
said member, and
means for mounting said member beneath said table with said member
bore aligned to said table bore to allow the running of a string of
tubing through said table and member to said subsea well and said
tubing hanger through said table into landed engagement on said
member, wherein said means for mounting said member is provided
upon said vessel for mounting said member on said vessel beneath
said table and to the support structure for said rotary table.
2. A coupling means for coupling a riser string of tubing to a
floating vessel over a subsea well to which said string is run,
said vessel having a rotary table mounted upon a support structure
on said vessel and having a table bore therethrough positioned over
a path to said well, said coupling means comprising:
a support member having a bore for the passage of tubing
therethrough and means for supporting a tubing hanger landed in
said member, and
means for mounting said member beneath said table with said member
bore aligned to said table bore to allow the running of a string of
tubing through said table and member to said subsea well and said
tubing hanger through said table into landed engagement on said
member, wherein said means for mounting said member is provided
upon said vessel for mounting said member on said vessel beneath
said table, and
wherein said member is provided with an outlet means for connection
to a vessel associated fluid line provided on said vessel so that,
upon landing of said riser string of tubing run through said table,
said vessel associated fluid line is automatically placed in fluid
communication with the interior of said tubing string supported by
said member.
3. The coupling means of claim 2 wherein:
said vessel associated line is a mud return line for receiving mud
return from said well through said riser string during drilling
operations, a drill string is run through said member down within
said riser string, providing a mud return passage therebetween,
and
closure means are provided above said tubing hanger means and about
said drill string for closing said member bore and said mud return
passage during drilling operations.
4. A coupling means for coupling a riser string of tubing to a
floating vessel over a subsea well to which said string is run,
said vessel having a rotary table mounted upon a support structure
on said vessel and having a table bore therethrough positioned over
a path to said well, said coupling means comprising:
a support member having a bore for the passage of tubing
therethrough and means for supporting a tubing hanger landed in
said member, and
means for mounting said member beneath said table with said member
bore aligned to said table bore to allow the running of a string of
tubing through said table and member to said subsea well and said
tubing hanger through said table into landed engagement on said
member, wherein said means for mounting said member is provided
beneath said vessel and includes constant tension reel winches on
said vessel and cables run between said member and said winches to
position said member in said sea beneath said vessel.
5. The coupling means of claim 4 wherein a second support member
having a bore for the passage of tubing therethrough is provided
having a second means for supporting a second tubing hanger
thereon;
a second means for mounting said second member is provided upon
said vessel beneath said table with said second member bore aligned
to said table bore; and
telescoping joint means are landed through said table bore upon
said second support member for providing a telescopic connection
between said riser string hung beneath said vessel and said second
support member on said vessel.
6. The coupling means of claim 5 wherein said second member is
provided with an outlet means for connection to a vessel associated
fluid line provided on said vessel so that, upon landing of said
riser string through said table on said first mentioned support
member and the landing of said telescopic joint means into
engagement with said riser and on said second member, said vessel
associated fluid line is automatically placed in fluid
communication with said riser string.
7. A fluid line coupling means for coupling a riser, run from a
floating vessel to a subsea well, with a vessel associated fluid
line automatically upon locating said riser relative to said
vessel, said coupling means comprising:
a housing including a central bore for the passage of tubing
therethrough and means for mounting it on said vessel, said housing
having an outlet for connection of said vessel associated line to
the interior of said housing;
hanger means associated with the upper end of a riser string run
from said vessel; and
means in said housing associated with said bore for supporting said
hanger means when the latter is landed within said housing upon
running of said tubing through said housing bore to place the
interior of said riser string in communication with the interior of
said housing and its outlet to said vessel associated line.
8. The fluid line coupling means of claim 7 wherein:
said hanger means includes a telescoping joint connection with an
upper part of said riser string.
9. A fluid line coupling means for coupling a riser, run from a
floating vessel to a subsea well, with a vessel associated fluid
line automatically upon locating said riser relative to said
vessel, said coupling means comprising:
a housing and means for mounting it on said vessel, said housing
having an outlet for connection of said vessel associated line to
the interior of said housing;
hanger means associated with the upper end of a riser string run
from said vessel; and
means in said housing for supporting said hanger means, landed
within said housing with the interior of said riser string in
communication with the interior of said housing and its outlet to
said vessel associated line, wherein:
said vessel is provided with a rotary table mounted on a support
structure and said housing is mounted to said support structure
beneath said table, and
said housing has a through bore aligned with an opening through
said table to allow running of said riser string and its hanger
means through said table to be landed in said housing.
10. The fluid line coupling means of claim 9 wherein:
said vessel associated line is a mud return line for receiving mud
returns from said wellhead through said riser string during
drilling operations, a drill string is run through said housing
from within said riser string, providing a mud return passage
therebetween, and
housing closure means are provided above said riser hanger means
and about said drill string for closing said through bore and said
mud return passage during drilling operations.
11. A fluid line coupling means for coupling a riser, run from a
floating vessel to a subsea well, with a vessel associated fluid
line automatically upon locating said riser relative to said
vessel, said coupling means comprising:
a housing and means for mounting it on said vessel, said housing
having an outlet for connection of said vessel associated line to
the interior of said housing;
hanger means associated with the upper end of a riser string run
from said vessel, wherein said hanger means includes a ball and
socket joint connection with an upper part of said riser string;
and
means in said housing for supporting said hanger means, landed
within said housing with the interior of said riser string in
communication with the interior of said housing and its outlet to
said vessel associated line.
12. In a subsea well assembly including a vessel floating on the
surface of the sea over a wellhead on the sea bottom; a rotating
table structure mounted in the vessel; a fluid line on said vessel
for receiving well fluid; a riser string extending from the vessel
beneath the table structure and down through the sea to the
wellhead, said riser having a telescoping joint with relatively
movable upper and lower parts which compensate for the motion of
the vessel; and a removable operating string extending through the
table structure, to be rotatively driven thereby and extending down
through the riser string into the wellhead, said strings together
providing a fluid passage therebetween, the improvement comprising
the provision of:
coupling means mounted to the table structure and mounting the
upper part of the riser string for releasably connecting the fluid
line to the fluid passage to conduct fluid therebetween, said
coupling means having a hollow interior of sufficient inside
dimensions to permit insertion and removal of the strings without
disconnecting the fluid line from the coupling means.
13. The invention as in claim 12 wherein the coupling means
includes:
a hollow tubular housing with an open upper end and an open lower
end, said housing including an annular flange adjacent the upper
end thereof for being mounted to the table structure to locate the
upper end of the housing directly below and coaxial with the table
structure, a tubular protrusion extending radially outwardly from
the housing for connection to the fluid line to receive fluid from
the housing, and an inwardly extending upwardly facing landing
shoulder formed in the lower end of the housing for receiving a
hanger means on the upper part of the riser string.
14. The invention as in claim 12 wherein the coupling means
additionally includes:
a tubular insert sized for insertion into the upper open end of the
housing to close the upper open end around the operating string run
through the housing, said insert having radial passages and a
circumferential groove therearound in communication with the radial
passages to collect the fluid from the space between the operating
string and the riser string and to deliver said fluid to said fluid
line.
15. The invention as in claim 12 wherein the coupling means
includes:
a hollow elongated housing with open upper and lower ends;
means for mounting the housing to the table structure;
means for connecting the vessel associated fluid line to the
housing;
hanger means for removably hanging the upper part of the riser
string from within the housing; and
means for conducting fluid from the fluid passage to said
connecting means.
16. The invention as in claim 15 wherein the means for conducting
the fluid from the passage includes:
guide means provided in the housing and having a central bore in
communication with the interior of the riser string landed in the
housing, said guide means forming a circumferential fluid
collecting cavity within said housing and having a plurality of
radial passages connecting its central bore therewith, and
housing closing means provided in the housing about the operating
string and over the guide means for closing the upper open end of
the housing above the guide means to prevent the fluid from
escaping therethrough.
17. The invention as in claim 16 wherein the housing closing means
includes a tubular insert sized for insertion into the housing,
said upper portion of the tubular insert being sized to mate with
the hollow of the housing and shaped for receiving a packer insert
therein, and includes a packer insert located in said upper portion
for engaging the operating string run through the housing.
18. A method of completing the landing of a riser string between a
floating vessel, having a rotary drilling table with a table bore
therethrough, and a subsea well comprising the steps of:
running a string of tubing through said rotary table bore to said
well, and
landing a hanger associated with said tubing on a support member
associated with said vessel by running said hanger through said
table bore into landed engagement with said member, wherein said
member is supported from and beneath said vessel in the sea above
said well and said step of running said hanger through said table
bore includes the substep of running said hanger into the sea
beneath said vessel and into said landed engagement in the sea
above and spaced from said subsea well.
19. A method of completing the landing of a riser string between a
floating vessel, having a rotary drilling table with a table bore
therethrough, and a subsea well comprising the steps of:
running a string of tubing through said rotary table bore to said
well, and
landing a hanger associated with said tubing on a support member
associated with said vessel by running said hanger through said
table bore into landed engagement with said member, wherein said
member is supported beneath said table and said step of landing
said hanger includes the substep of landing said hanger directly
below and adjacent to the underside of said rotary table.
20. A method of completing the landing of a riser string between a
floating vessel, having a rotary drilling table with a table bore
therethrough, and a subsea well comprising the steps of:
running a string of tubing through said rotary table bore to said
well,
landing a hanger associated with said tubing on a support member
associated with said vessel by running said hanger through said
table bore into landed engagement with said member, and
automatically connecting the interior of said string to a vessel
associated line by the landing of said string and associated hanger
upon said support member.
21. A method of completing the assembly of a subsea well assembly
comprising the steps of:
mounting a tubular open ended housing to the rotating table
structure of a floating vessel;
running a riser string through the table and housing; and
landing an upper end of said string in said housing.
22. The method of claim 21 including the steps of:
coupling a fluid line to the housing; and
automatically connecting the interior of the riser string to the
housing and the line upon landing the riser string by its hanger
means in the housing.
23. The method as in claim 22 additionally comprising the steps
of:
inserting a preassembled insert assembly into the housing over the
upper part of the riser string; and
running an operating string through the insert assembly, through
the housing, and into the riser string while the insert assembly
closes the upper end of the space between the operating and riser
strings.
24. The method as in claim 23 additionally comprising the steps
of:
removing the operating string through the housing without
disconnecting the fluid lines; and
reinserting the operating string through the housing without
disconnecting the fluid lines.
25. A coupling means for coupling a riser string of tubing to a
floating vessel over a subsea well to which said string is run,
said vessel having a roatry table mounted upon a support on said
vessel and having a table bore therethrough and positioned over a
path to said well, said coupling means comprising:
a riser string supporting means having a central bore to allow
passage of said string of tubing therethrough and means for
supporting a riser string associated tubing hanger therein, and
means for mounting and positioning said supporting means beneath
said rotary table with said central bore aligned to said table bore
to allow running of said riser string of tubing through said table
bore and central bore in said path to said well and said tubing
hanger through said table to land on said supporting means.
Description
BACKGROUND OF THE INVENTION
The present invention relates in general to subsea well apparatus
for coupling a string of tubing, as a riser string, to a floating
vessel over a subsea well to which the string is run. More
particularly, the present invention relates to a coupling means
positioned beneath the bore of a rotary table structure provided
upon the floating vessel to allow the running of the string of
tubing through the rotary table bore and the landing of a riser
string hanger means in the support member.
Conventionally, in subsea well drilling and production operations,
a vessel or platform floating on the surface of the sea is
connected to a subsea wellhead by a riser string and an operating
string, i.e., drilling or production string, is run from the vessel
or platform through the riser to the wellhead therebelow. As the
vessel is floating, it is constantly moving relative to the
wellhead, and, therefore, the riser string is provided with a
telescoping joint to compensate for this movement. Heretofore, if
the telescoping joint was located at the lower end of the riser
string adjacent the wellhead, then the riser string was hung
statically from the vessel directly. If the telescoping joint was
located at the upper end of the riser string adjacent the vessel,
then the riser string was dynamically hung from cables attached
thereto, below the telescoping joint, and run from constant reel
winches on the vessel to provide a constant lifting force. The
lifting force is required to prevent the riser string below the
joint from buckling under its own weight. The running and
positioning of such strings has been very difficult and time
consuming heretofore.
Also, conventional oil well operations, such as drilling, for
example, requires that a hydraulic fluid, commonly called mud, be
supplied to the drill bit to keep the bit clean and remove
aggregate produced during drilling. A pressurized supply of such
mud is kept on the vessel, and, typically, is fed by a supply line
down the center of the drill string to the drill bit on the lower
end thereof. The mud passes through the drill bit to clean it and
is forced along with the displaced aggregate, etc., up the space
between the drill string and the riser string back to the vessel
where a return line receives the mud to return the mud to the
supply tank on the vessel. With the heretofore used coupling means
for coupling the return line to the strings, the riser string was
not automatically coupled to the mud return line upon being hung
from the vessel. Further, it was necessary to uncouple the return
line each time a section of riser string was added or removed. Such
manual connecting, disconnecting and removing of the mud return
line each time the riser was located or a section of riser string
was added required considerable time and effort, delaying
production operations.
BRIEF DESCRIPTION OF THE INVENTION
Therefore, it is the primary object of the present invention to
provide and disclose an improved method and apparatus for coupling
the upper end of a riser string to the floating vessel from which
it is run.
It is another object of the present invention to disclose and
provide a coupling means as in the foregoing object wherein the
method and apparatus allow for the running of the riser string of
tubing through the rotary table bore through a path to a subsea
well and the landing of a riser string hanger in a support member
positioned beneath the rotary table.
It is also an object of this invention to provide an improved novel
mud or fluid return line coupling between a vessel associated
return line and a riser string run from and supported from such
vessel to a subsea well apparatus, and particularly such a coupling
which automatically connects the riser string to the vessel return
line upon the landing or locating of the upper end of the riser
string in association with the vessel.
Other and additional objects of this invention are to provide such
a coupling means which is mounted to the underside of the otherwise
conventional rotary table structure on the vessel or platform; to
provide such a coupling means in which the upper end of the riser
string may be landed to automatically connect to the return line on
the vessel and to receive the operating or drill string
therethrough; to provide such a coupling means which mounts a
return line so as to permit sections of the string to be added to
or removed therefrom without uncoupling the return line; and to
provide such a coupling means which eliminates unproductive
coupling and uncoupling of the return line to increase the
productive operating time of the drilling or production operations
on a well.
Generally stated, the coupling means of the present invention for
coupling a riser string of tubing to a floating vessel over a
subsea well to which the string is run includes the provision of a
support member having a bore therethrough for the passage of tubing
and means for supporting a tubing hanger to be landed in the
support member. Means are provided for mounting the support member
beneath the table with the support member bore aligned to the table
bore so that, in accordance with the method and apparatus of the
present invention, the riser string of tubing may be run through
the table bore to the well and the tubing hanger may be run also
through the table bore and into landed engagement on the support
member. In one exemplary embodiment of the invention, a support
member is mounted on the vessel, preferably to the support
structure for the rotary table to position it directly beneath and
adjacent to the underside of the rotary table. In a second
embodiment of the invention, the support member is mounted beneath
the vessel in the sea by suitable means, such as constant tension
cable run from constant tension reel winches provided upon the
vessel.
More specifically, in a preferred exemplary embodiment of the
method and apparatus for coupling a riser string to a floating
vessel according to the present invention, the riser string support
member is provided with a coupling means connected to a fluid line
on the vessel. The support member is provided so that upon landing
of the riser string by its hanger in the support member, the
interior of the riser string is placed in fluid communication with
the fluid return line on the vessel via the support member
connection. Closure means, in accordance with the present
invention, are also provided in the support member for directing,
collecting, and guiding fluid returns from the well through the
support member to the vessel associated return line and to provide
a removable fluid seal at the upper end of the riser string. Such
seal preferably includes a diverter insert, a blowout-preventer
insert, and a packer insert.
Further objects and advantages of the coupling means apparatus and
method of providing a coupling between a riser string and a
floating vessel over a subsea well, of the present invention, as
well as a better understanding thereof, will be afforded to those
skilled in the art from a consideration of the following detailed
explanation of preferred exemplary embodiments thereof. Reference
will be made to the appended sheets of drawings which will now be
first described briefly.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of a subsea well assembly
including a floating vessel located over a subsea well with guide
lines and a riser string of tubing running from the vessel to the
subsea wellhead with a preferred exemplary embodiment of coupling
means, according to this invention, connecting the riser string to
the vessel;
FIG. 2 is an enlarged, fragmentary, partially cutaway, side
elevational view of the coupling means of FIG. 1 during the
positioning therein of a riser hanger having a ball joint by a
running tool to mount the upper part of a riser string thereto;
and
FIG. 3 is an enlarged, fragmentary, partially cutaway, side
elevational view of the coupling means with a ball socket joint
riser hanger means landed therein, a diverter insert, a
blowout-preventer insert, and a packing insert therein, said riser
including a telescoping joint in its upper portion adjacent the
vessel with cables from constant tension reel winches on the vessel
supporting the lower part of the riser string.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, the preferred embodiments of
coupling means apparatus and methods of coupling a riser string to
a floating vessel will now be described in detail.
The subsea well assembly includes a vessel 12 floating on the
surface of the sea 13 over a subsea wellhead 14 located on the sea
bottom 15. The vessel 12 is tied to the wellhead 14 by wire guides
16 which will guide parts from the vessel 12 to the wellhead 14 for
attachment thereto. The vessel 12 typically has a derrick 17
thereon over a well or opening through the vessel which facilitates
the lowering of parts to the wellhead 14 and the raising of parts
from the wellhead 14.
Referring now to FIGS. 2 and 3, the vessel 12 also includes a
rotating table structure 20 located below the derrick 17. The
structure 20 has I-beams 21 from the vessel 12 on which are mounted
a stationary platform 22 which has a large hole therein for
receiving and drivingly rotatably mounting a rotating table 23. The
rotating table 23 has a square cross-section hole 24 therein for
rotatively driving oil well tools. Sections of the rotary table 23
are removable to provide access to the area below the table 23 or
to allow large oil well tools to pass therethrough. The derrick 17
is adapted to lower or raise oil well tools through the rotating
table 23 in conventional manner.
The vessel 12 also typically has a pressurized supply of fluid,
commonly called mud, which is for use with a rotating tool, as a
drill bit, in the wellhead 14. The supply has a supply line (not
shown) which connects to the operating string 45 to supply the mud
down the center thereof to the wellhead 14 and to the lower end of
the operating string for washing the rotating tool thereon. After
washing the tool, the mud is forced up a mud return space,
indicated at 50 in FIG. 3, between the operating string 45 and the
riser string 30 to be fed into a mud return line 51. Heretofore,
the mud return line 51 was coupled directly to the upper end of the
riser string 30 and has to be coupled and uncoupled each time the
riser, or its sections were landed or removed. The coupling means,
according to this invention, eliminates the steps of coupling,
uncoupling, and recoupling the mud return line to the riser
string.
Generally, the preferred exemplary embodiment of coupling means,
according to this invention, is indicated at 10 and is mounted to
the table structure 20 as seen in FIGS. 2 and 3. The coupling means
mounts the upper part 32 of the riser string 30 for releasably
connecting the well fluid or mud return line 51 to the fluid return
passage 50 to conduit fluids therebetween. The coupling means 10 of
the preferred embodiment includes an elongated housing 60, means 65
for mounting the housing 60 to the table structure 20, connecting
means 70 for connecting the vessel associated mud return line 51 to
the housing 60, hanger means 75 for removably hanging the upper
part 32 of the riser string 30 from within the housing 60, and
conducting means 80 for conducting the mud from the mud return
passage 50 to the connecting means 70. The conducting means 80 may
include mud guide means 81 for guiding the flow of mud from the mud
return passage 50 towards the connecting means 70 and housing
closing means 90 for closing the housing 60 about the operating
string 45 above the mud guide means 81 to close the upper end of
the mud return space 50 and thereby prevent mud from escaping
therethrough.
The riser string 30 is constructed of many hollow tubing sections
and is run from the vessel 12 to the subsea wellhead 14 to provide
a conduit therebetween from which the sea 13 is excluded. Because
the vessel 12 is floating on the surface of the sea 13, the riser
string 30 is provided with a telescoping joint 31 which divides the
string 30 into an upper portion 32 and a lower portion 35. The
upper portion 32 has a ball and socket joint 33 from which an inner
sleeve 34 depends to be received in the lower portion 35.
Where the lower portion 35 of the tubing string is so long that it
will not support its own weight, as in the exemplary embodiment, a
supporting ring or member 40 is provided as part of the coupling
means for hanging the lower portion 35 of the tubing string from
the vessel 12. The supporting ring 40 receives the tubing hanger 38
of the tubing string 35 which is run through the table bore,
according to the method of the present invention, to land on the
member 40. Ears 41 are provided on member 40 to which cables 42 are
attached. The cables 42 are wound upon constant reel winches 43, of
conventional construction, on the vessel 12 to carry the weight of
the lower portion 35 of the riser string 30.
The housing 60 of the preferred embodiment of the mud return line
coupling means 10 is best seen in FIGS. 2 and 3. The housing 60 is
generally tubular in shape and has an open upper end 61 and an open
lower end 62 with a hollow central bore 63 therebetween. The
housing 60 is large enough that the central bore 63 therethrough
will have sufficient dimensions for the riser string 30 to be
passed therethrough by the derrick 17.
The means 65 for mounting the housing 60 to the table structure 20
includes, in the preferred embodiment, an annular flange 66
extending radially outwardly from the housing 60 at a location
spaced slightly from the upper end 61. Vertically oriented
triangular reinforcing flanges 67 are provided between the annular
flange 66 and the housing 60. The flange 66 is for being secured to
the lower flange of the I-beams 21 by a suitable means, such as
welding, to coaxially locate the housing 60 below the rotary table
23 for receiving the strings 30 and 45 therethrough.
Connecting means 70 is provided for connecting the vessel
associated mud return line 51 to the housing 60. In the preferred
embodiment, the connecting means 70 includes the provision of a
tubular protrusion or outlet 71 on the housing 60 below the annular
flange 66. The protrusion 71 extends radially outwardly from the
housing 60 to terminate in an outer end 72. The outer end 72 is
suitably sized to receive thereover the end of the mud return line
51, which is clamped thereto by a clamp 73. The protrusion 71 is
provided with a central passage 74 which opens the hollow central
bore 63 of the housing 60 to the mud return line 51 to conduct mud
therebetween.
The hanger means 75 for removably hanging the upper part 32 of the
riser string 30 from within the housing 60 includes, in the
preferred embodiment, a circumferential ridge 76 adjacent the upper
end of the ball and socket joint 33, which provides a downwardly
facing landing shoulder 77. The housing 60 includes an inwardly
extending lower lip 78 at the lower end 62 thereof which provides
an upwardly facing shoulder 79 which is suitably sized to landingly
receive the shoulder 77 thereagainst to hang the riser string 30
from within the housing 60. It should be noted that the upper end
of the ball and socket joint 33 which is the upper end of the riser
string 30 is located below the entrance of the central passage 74
into the central bore 63 of the housing 60 so that conducting means
80 can be received within the housing 60.
Conducting means 80 is provided for conducting the mud from the mud
return passage 50 to the central passage 74 of the connecting means
70. The conducting means 80, of the preferred embodiment, includes
mud guide means 81 for guiding the flow of mud from the mud return
passage 50 to the central passage 74 and housing closing means 90
for closing the upper open end of the mud return passage 50 above
the mud guide means 81 to prevent the mud from escaping
therethrough.
As best seen in FIG. 3, the mud guide means 81 includes the lower
portion of a diverter insert 82 which is sized to be snuggly
received in the bore 63 of the housing 60 above the ball and socket
joint 33. The diverter insert 82 is provided with a vertical
central bore 83 from which four radial passages 84 extend to open
into a circumferential groove 85. When the diverter insert 82 is
located in the housing 60, the circumferential groove 85 forms with
the housing 60 and the ball and socket joint 33, a mud collecting
cavity 86 which is aligned with and in communication with the
central passage 74 of the connecting means 70 to direct the mud
thereinto.
The diverter insert 82 also acts as part of the housing closing
means 80 for closing the housing 60 above the mud collecting cavity
86. An upper portion of the diverter insert 82 is suitably sized to
be snuggly received in the upper end 61 of the housing 60 where it
is retained by a latch dog 91 mounted to the housing 60 and
typically hydraulically actuated. The diverter insert 82 has an
upper annular cutout 92 into which is received a blowout-preventer
insert 93 which is secured therein by a ring 94. The ring 94 has a
spring latch mechanism 95 for latching a packer insert 96 inserted
into the blowout-preventer insert 93 and ring 94. The packer insert
96 extends to sealingly engage the operating string 45 and
completes the closing of the upper end 61 of the housing 60 to
prevent the escape of mud therefrom.
With the housing 60 mounted to the rotary table structure as
disclosed herein, the end of the mud return line 51 is inserted
onto the outer end 72 of the protrusion 71 and clamped by clamp 73
to remain so clamped until the line 51 needs to be repaired. The
housing 60 is automatically ready to receive the riser string 30
therein. If another support member, as support ring 40, is needed,
it is located directly beneath the housing 60 and coaxial
therewith, while the derrick 17 lowers sections of the lower part
35 of the riser string 30 through the rotating table 23, through
the housing 60, through the support ring 40, if required, down into
the sea 13 to be guided by guide lines 16 to the wellhead 14. When
the enlarged upper end passes through the housing 60, it will then
land on the support ring 40 to hang the lower part 35 of the riser
string 30 from the vessel 12 for receiving the upper part 32. As is
illustrated in FIG. 2, the upper part 32 of the riser string 30 may
be run by the hanger tool 46 through the rotating table 23, through
the housing 60 until the inner sleeve 34 telescopes into the outer
sleeve 37 to provide the telescoping connection at 31 and until the
shoulder 77 of the ball and socket joint 33 lands on the shoulder
79 of the housing 60, thus landing riser string 30 within the
housing 60. The hanger tool 46 is then removed.
An assembly of the packer insert 96, the blowout preventer 93, the
ring 94, and the diverter insert 82 is preassembled and inserted
into the upper end 61 of the housing 60 to rest on the upper end of
the ball and socket joint 33. This assembly is held in the housing
60 by the latch dog 91 for receiving the operating string 45
therethrough. The operating string 45 extends down the riser string
30 and into the wellhead 14. The upper end of the operating string
45 is non-rotatably secured in the square cross section hole 24 to
be rotatably driven by the rotating table 23 and the supply mud
line (not shown) is connected thereto to supply the mud down the
center thereof to the rotating tool (not shown) mounted on the
lower end of the operating string 45. The mud from the tool is
forced up the mud return space 50 to pass into the central bore 83
of the diverter insert 82, where its upward progress is blocked by
the blowout-preventer insert 93 and the packer insert 96, so that
the mud flows through the radial passages 84 and into the mud
collecting cavity 86. From the cavity 86, the mud flows down the
central passage 74 of the tubular portion 71 and into the mud
return line 51 to be returned to the mud supply. The flow of mud
will continue as long as needed.
From the foregoing detailed description of method and apparatus for
providing a coupling between a riser string and a floating vessel,
from which the string is run to a subsea well, it should be
apparent to those skilled in the art that the objects and
advantages aforestated for the present invention have been
attained. Once the floating vessel is located over the well with
the rotary table bore positioned with a clear path between it and
the well, the apparatus and method of the present invention allow
the running of the riser string of tubing down through the rotary
table bore and into landed engagement with a support member
positioned beneath the table. Such support member, according to the
method of the present invention, may comprise the ring means 40
positioned in the sea beneath the vessel, a housing mounted on the
vessel beneath the table or, as in the preferred exemplary
embodiment, a combination of the two to provide a telescoping joint
connection between the upper end of the riser string and the
floating vessel ready to receive additional tools, as a drilling
string. Further, the riser string, according to the method and
apparatus of the present invention, is automatically interconnected
with a return line on the vessel upon the landing of the upper end
of the riser string in the connecting means support member. Well
fluid returns from within the riser are directed, collected, and
passed to the vessel associated return line while the upper end of
the riser string is sealed about an operating string run
therethrough.
* * * * *