US3500906A

US3500906A - Subsurface wellhead and connector

Info

Publication number: US3500906A
Application number: US731382A
Authority: US
Inventors: William H Petersen
Original assignee: Shell Oil Co
Current assignee: Shell USA Inc
Priority date: 1968-05-23
Filing date: 1968-05-23
Publication date: 1970-03-17
Anticipated expiration: 1987-03-17
Also published as: DE1926001A1; GB1265355A; FR2009180A1; JPS5016722B1

Description

March 17, 1970 w, PETERSEN 3,500,906

SUBSURFACE WELLHEAD AND CONNECTOR Filed May 25, 1958 3 Sheets-Sheet 1 m. ii i l;

INVENTORI I WILLIAM H. PETERSEN HIS ATTORNEY March 17, 1970 w. H. PETERSEN 3,500,906 V SUBSURFACE WELLHEAD AND CONNECTOR Filed May 23, 1968 3 Sheets-Sheet 2 INVENTORI WILLIAM H. PETERSEN HIS ATTORNEY March 17, 1970 w. H. PETERSEN 3,500,906

SUBSURFACE WELLHEAD AND CONNECTOR Filed May 23, 1968 3 Sheets-Sheet 5 INVENTORI WILLIAM H. PETERSEN HIS ATTORNEY United States Patent 3,500 906 SUBSURFACE WELLHEAD AND CONNECTOR William H. Petersen, Houston, Tex., assiguor to Shell Oil Company, New York, N.Y., a corporation of Delaware Filed May 23, 1968, Ser. No. 731,382 Int. Cl. E2111 7/12, 33/035 US. Cl. 166-.6 7 Claims ABSTRACT OF THE DISCLOSURE Apparatus for making a remote operative connection between a floating vessel and an underwater wellhead assembly. The wellhead assembly and a wellhead connector lowerable from the vessel include cooperating orienting means and means to attach guide lines depending from the vessel to the assembly.

The present invention relates to apparatus for use at underwater oil well locations and, more particularly, to apparatus for making a remote connection between a subsurface production wellhead assembly and a floating vessel.

A recent development in the field of oil well drilling is the completion of wells at offshore locations with a wellhead assembly positioned on or close to the ocean floor out of the way of ships which might otherwise damage it in the event of collision. Equipment placed on the ocean floor, however, is exposed to conditions such as the corrosive nature of the sea water and the presence of marine life which tends to grow and become encrusted on metallic structures below the surface of the water.

It is necessary therefore from time to time to go back into a well wherever it has been completed for serv cing or work-over operations. In addition, the underwater wellhead assembly itself may call for periodic repair and maintenance. Due to the problems peculiar to undersea operations of this type it has been necessary to design and develop entirely new equipment for this purpose. For example, an underwater wellhead assembly has been devised which may be readily removed from its associated underwater wellhead and raised to the surface for maintenance or other purposes. An assembly of this nature is disclosed in US. Patent No. 3,064,735, issued Nov. 20, 1962, to R. J. Bauer et al.

'In accordance with present practice, maintenance or other undersea operations relating to a producing wellhead assembly are initiated by establishing guide means, such as guidelines, between the floating vessel and the well site. A suitable wellhead connector device is then normally lowered by means of a pipe string along the guide means to the wellhead assembly. After suitable attachment has been made between the connector and the wellhead assembly and the required disconnect operations have been performed with respect to the wellhead assembly and the wellhead, the assembly is pulled up to the vessel along the guide means by means of the pipe string. If desired, a new wellhead assembly may then be lowered along the guide means and operatively attached to the wellhead and production may be resumed. Alternatively, the original assembly after inspection and/or repair on board the vessel may be returned to its operative position on the wellhead along the guide means.

The two steps outlined above of (1) establishing guide means between the vessel and the wellhead assembly and (2) lowering the connector onto the assembly are separately often time'consuming and time is an important consideration in offshore oil operations due to the large per diem expenses involved in the rental of barge equipment, wages, etc. Accordingly, it is advantageous to per- 'ice form maintenance and work-over operations relating to an undersea well as quickly as possible.

SUMMARY OF THE INVENTION It is therefore a primary object of the present invention to provide apparatus whereby a remote operative connection between a floating vessel and an underwater wellhead assembly can be made at substantially the same time as guideline means are established between the vessel and the underwater well site.

A further object of the present invention is to provide cooperating means on an underwater wellhead assembly and a wellhead connector to orient said wellhead connector with respect to said wellhead assembly so that it may be placed into operative engagement therewith.

These objects have been attained in the present invention by providing a wellhead connector lowerable from a floating vessel into engagement with an underwater wellhead assembly. Orienting means, including a pin and slot arrangement, is employed on the connector and the assembly to effect a predetermined relative position with respect thereto. After such orientation has taken place the conductor and assembly are locked into engagement and guideline means, including latch means, are fastened to upstanding guide post means fixedly positioned with respect to the wellhead assembly.

DESCRIPTION OF THE DRAWING These and other objects of this invention will be understood from the following description taken with reference to the drawing, wherein:

FIGURE 1 is a diagrammatic view taken in longitudinal projection illustrating a floating drilling vessel positioned at the surface of a body of water with the elements of the present invention shown prior to operative engagement there'between;

FIGURE 2 is a longitudinal, enlarged, partial crosssectional view illustrating details of the present invention with the elements thereof being positioned prior to operative engagement;

FIGURE 3 is an isometric, enlarged, partial cross-sectional view illustrating details of the present invention with the elements thereof placed in operative engagement;

FIGURE 4 is an isometric cross-sectional view illusstrating one form of entry conduit closure device employed in the present invention;

FIGURE 5 is an isometric exploded view illustrating a portion of an alternate form of entry conduit closure device; and

FIGURE 6 is an enlarged frontal view of the apparatus according to the present invention.

Referring to FIGURE 1 of the drawing, a drilling vessel or barge 11 of any suitable floatable type is illustrated as floating on the surface of a body of water 12 and substantially fixedly positioned over a preselected location by suitable barge positioning means or by being anchored to the ocean floor 13 by suitable anchors (not shown) connected to anchor

lines

14 and 15. Equipment, of this type may be used when carrying on operations in water depths varying from about 100 to 1500 feet or more. The vessel is equipped with a suitable derrick 16 as well as other auxiliary equipment needed during well work-over or maintenance operations. The derrick 16 is positioned over a slot 17 which extends vertically through the vessel in a conventional manner. When using the equipment of the present invention, the slot of vessel 11 may be either in. Strings of production tubing and 21 are suspended within the well casing and extend into the well in the usual manner.

Positioned on base member 18 is a casinghead unit 24 with a wellhead assembly or production control unit 25 attached thereto. Normally, the production control unit or wellhead assembly is in fluid communication with the production tubing and comprises the necessary piping, valves, chokes, and other equipment normally connected together and mounted on the top of a well, and known as a Christmas tree, together with the necessary hydraulic or electrical systems, including pumps, reservoirs, motors, etc., to operate the valves at the head of the well from a remote location. A typical example of a suitable underwater production control unit or wellhead assembly for use at an offshore well location, and its manner of operation, is shown and described in the aforementioned US, Patent No. 3,064,735, issued Nov. 20, 1962, to R. J. Bauer et al. For purposes of illustration it will be assumed that the wellhead assembly utilized in conjunction with the present invention will be similar to that described in the above patent, although it is of course obvious that the present invention could be utilized with other suitable wellhead assembly designs. Wellhead assembly 25 includes a pair of radially projecting fluid flow handling conduits or

production flowlines

26 and 27 and an upstanding wellhead entry conduit 28. Fluid

flow handling conduits

26 and 27 communicate with production tubing strings 20 and 21, respectively, and are smoothly curved in an are which would permit objects, such as through-the-flowline tools to be circulated therethrough into the well.

As may cost clearly be seen with reference to FIGURE 2, upstanding wellhead entry conduit 28 has fixedly disposed therein, such as by means of plate member 29,

connector elements

30 and 31 which comprise lengths of tubing in communication at their lower ends with production tubing strings 20 and 21. During the actual well production operation valve means (not shown) interrupts the fluid communication between

tubing strings

20 and 21 and their

respective connector elements

30 and 31. U.S. Patent No. 3,064,735 may again be referred to for a more detailed description of an arrangement of this type.

Wellhead entry conduit 28 differs from that disclosed in the aforementioned patent in that a pair of

indents

32 and 33 are disposed in opposition to one another as shown at the upper end thereof in the manner shown in FIGURES 2 and 3. In addition two tapered keyway channels or grooves 34 and 35 (FIGURE 3) are provided in the outer cylindrical wall of entry conduit 28 for the purpose which will be more fully brought out below. Preferably, the upper end of entry conduit 28 is closed by means of a suitable end closure device, such as closure member 36, to help protect the interior of the entry conduit from the possible harmful effects of the sea water, sediment, etc. As may be seen with reference to FIGURE 4, closure member 36 comprises a circular disc 37 constructed of rubber or other suitable resilient material which is cut into a plurality of independently movable wedge members 38. When in the unstressed position illustrated, wedge members 38 form a substantially liquidtight seal with one another. Integrally attached to disc 37 is a downwardly depending, circular flange member 39, which is adapted to be positioned against the inner wall of entry conduit 28 and secured thereto by any desired expedient. The chamber within entry conduit 28 which is defined at one end by closure member 36 and at the 4 other end by plate member 29 (FIGURE 2) is preferably filled with non-buoyant oil or grease (not shown) which provides additional protection against the harmful effects of the sea water.

FIGURE 5 illustrates an alternative embodiment of an end closure device which may be used to protect the interior of entry conduit 28. As opposed to the relatively thick walled, one-piece construction of closure member 36, the end closure device may be comprised of a plurality of relatively thin-walled, disc-elements placed in face-to-face contact with one another. FIGURE 5 is an exploded view showing two such thin-walled, disc-

like elements

40 and 41. As with closure member 36, disc-

like elements

40 and 41 are divided into a plurality of

wedge members

42 and 43, respectively. Preferably the various disc-like elements comprising the end closure device should be angularly disposed with respect to one another so that the respective wedge members thereof overlap (as shown in FIGURE 5) to form a more effective seal.

Referring once again to FIGURES 1 and 2, a wellhead connector 44 of the general type disclosed in copending U.S. application Ser. No. 731,381, filed May 23, 1968, is shown suspended by means of a pipe string 45 from vessel 11. The wellhead connector has a frame means depending therefrom, by means of which guideline carrying means 46 and 47 are mounted. Wellhead assembly locating and positioning means including a hydraulically actuated, extensible sonar unit 48 and a television camera 49, of conventional design, are also frame-mounted on the connector. With particular reference to FIGURE 2, wellhead connector 44 includes a cylindrical body member 50 defining a throughbore into which extend tubing runs 51 and 52. Tubing runs 51 and 52 extend upwardly within pipe string 45 to vessel 11. Preferably the tubing runs 51 and 52 are each comprised of individual tubing sections of substantially the same length as the sections of pipe comprising pipe string 45 and are attached thereto by suitable internal frame means (not shown) to form integral units. An arrangement of this type is disclosed in U.S. application Ser. No. 690,996, filed Dec. 15, 1967. However, the tubing runs may be independently disposed within and along the length of pipe string 45 if desired. In any event, the lower ends of tubing runs 51 and 52 pass through a mounting plate means 53 and are connected thereto by any suitable means such as welding. Plate means 53 is integrally attached to a portion 54 of the body member 50 which is mounted for downwardly extensible axial movement with respect to the rest of the body member. Body member portion 54 is connected to pipe string 45 by means of a coupling member 55.

The body member portion 54 is normally biased by any suitable means, such as spring means (not shown), into the retracted position illustrated in FIGURE 2. A flange member 56 comprises an integral part of body member portion 54 and a resilient O-ring is preferably accommodated thereby which sealingly engages the inner Wall of body member 50. The annular space or chamber 57 formed between body member 50 and body member portion 54 communicates by means of conduits 58 with a series of hydraulic accumulators 59 which are fixedly disposed about body member 50. Suitable valve means (not shown) are positioned in conduits 58 to establish or break the fluid communication between the accumulators 59 and chamber 57 as desired. The actuation of these valves would be accomplished remotely from vessel 11 many well-known manner. It is to be understood that the valves referred to above are normally closed and upon actuation thereof will open to establish fluid communication between chamber 57 and the accumulators 59. Upon such actuation the hydraulic fluid will act upon flange member 56 forcing the body member portion 54,

tubing runsv

51 and 52, and pipe string 45 in a downward direction whereby the body member portion will be in its extended position. Rather than using the illustrated arrangement of accumulators and valves to pressure up chamber 57, a direct hydraulic circuit could be provided between chamber 57 and a suitable pressurized fluid source (not shown) on board vessel '11 through a hydraulic cable extending from the chamber to the vessel.

Latch members

60 and 61, which may be either spring or hydraulically operated, are disposed near the lower end of body member 50 in the manner shown in FIG- URE 2. A portion of each latch member extends through the body member 50 into the throughbore defined thereby. Disposed at a 90 degree angle from

latch members

60 and 61 and fixedly positioned on the inner cylindrical wall of body member 50 is a pin member 62. If desired, a second pin member (not shown) of similar construction may be mounted on the inner cylindrical wall of body member 50 in opposition to pin member 62.

The operation of the present invention will now be described. It will be assumed that vessel 11 has been positioned over the approximate location of the wellhead assembly 25 upon which the desired operations are to be performed. The most usual method of accomplishing this is by surveying in on the known site of the well by suitable instruments aboard the vessel. As soon as the well site has been surveyed in and the vessel 11 suitably oriented and positioned with respect to the wellhead assembly 25 by anchor or other means, the wellhead connector 44 and the other apparatus frame-mounted thereon are attached to pipe string 45 by coupling member 55 and lowered from the vessel by adding additional sections of pipe to the string in the customary manner. This operation continues until it is determined that sufficient pipe sections have been added to position the connector at a distance from the ocean floor 13 somewhat greater than the height of wellhead assembly 25.

At this point the sonar unit 48 and the television camera 49 are actuated and monitored from the vessel. The pipe string 45 and wellhead connector 44 are then manipulated from the vessel to position them in axial alignment with wellhead entry conduit 28 as illustrated in FIGURES 1 and 2. Pipe string 45 is then further lengthened to lower connector 44 into engagement with wellhead entry conduit 28. The cone-shaped element 63 which is integrally attached to the lower end of body member 50 will assist in maintaining axial alignment between connector 44 and entry conduit 28 as they are brought into engagement. As the lowering operation continues, the body member 50 and entry conduit 28 will assume the relative position shown in FIGURE 3. As may be clearly seen in that figure, pin member 62 on body member 50 is ready to enter into the keyway channel 35 of entry conduit 28. In addition, it will be assumed that the aforementioned second pin member (not shown) will similarly cooperate with keyway channel 34. Due to the tapered configuration of the keyway channels, still further lowering of body member 50 will serve to rotatably orient the wellhead connector 44 with respect to wellhead assembly 25 as shown in FIGURE 6. As is more fully disclosed in copending US. application Ser. No. 731,381, filed May 23, 1968, the lowering of connector 44 is terminated when the top of entry conduit 28 comes into contact with stop means 64 (FIGURE 2) defined by the inner wall of body member 50.

Latch members

60 and 61 are then actuated so that they are locked into

indents

32 and 33, respectively.

After the wellhead connector 44 has been rotatably oriented with respect to wellhead assembly 25 and locked into engagement therewith as above described, tubing runs 51 and 52 are axially aligned with

connector elements

30 and 31, respectively. The valves (not shown) in conduits 58 are then opened thereby forcing body member portion 54, tubing runs 51 and 52, and pipe string 45 in a downward direction in the manner which has been described above and is more fully set forth in copending U.S. application Ser. No. 731,381. As is also disclosed in the last referred to application, tubing runs 51 and 52 in this extended position form a fluid-tight seal with

connector elements

30 and 31, respectively. In the event an end closure device similar to those shown in FIGURES 4 and 5 is used, the body member portion will pass therethrough, due to the flexibility of the wedge members, as it is extended. Suitable well work-over or other operations may then be carried out from vessel 11.

FIGURE 6 illustrates the position assumed by the wellhead connector 44 after it has been rotatably oriented and locked into position in the manner previously described. It should also be noted that pipe string 45 has been pulled downwardly by virtue of its interconnection with body member portion 54. It will be obvious upon inspection of FIGURE 6 that after the above-outlined operations have been completed, guideline carrying means 46 and 47 are positioned over and axially aligned with

vertical guide columns

22 and 23, respectively. Slidably disposed in guideline carrying means 46 and 47 are

tubular members

65 and 66 having lower flanged ends 67 and 68 and apertured

top plates

69 and 70, respectively.

Guidelines

71 and 72 depending from vessel 11 pass through the apertures in the top plates and pass into the interior of

tubular members

65 and 66 in the manner shown.

Guidelines

71 and 72 have attached to the respective lower ends thereof guideline connector means, such as latching means 73, which may be of any known type. For example, US. Patent No. 3,050,140, issued on Aug. 21, 1962, to W. J. Hayes, discloses latching mechanisms which may be utilized for this purpose.

Guidelines

71 and 72 are each kept under constant tension by suitable apparatus such as winch means (not shown) on vessel 11 as the guideline carrying means 46 and 47 are lowered along with wellhead connector 4 from the vessel. This tension is maintained until the conhector has been positioned on and latched to the wellhead assembly as shown in FIGURE 6. When, however, the operator wishes to attach the guidelines to the respective guide posts the guidelines are allowed to slack from the vessel and the

tubular members

65 and 66 with their respective latching means are dropped onto the guide posts. The

tubular members

65 and 66 perform two main functions during this operation. First, the flanged ends thereof serve to guide the latch means onto the guide posts, and second, the weight of the tubular members helps to insure firm engagement between the latch means and the associated guide posts as they are dropped thereon. For purposes of clarifying this last-mentioned operation somewhat, guideline 71 is illustrated in FIGURE 6 as having been allowed to go slack from vessel 11, thus dropping tubular member 65 and latch means 73 into engagement with guide post 22. Guideline 72 is illustrated as still being maintained under tension from vessel 11 with tubular member 65 being maintained upwardly and flanged end 68 thereof being held in engagement with the lower end of guideline carrying means 47.

After the wellhead connector 44 has been connected as shown in FIGURE 6, and

guidelines

71 and 72 have been attached to their respective guide posts 22 and 23, the desired operations may be performed. For example, tools or instruments may be circulated down the well through the tubing runs 51 and 52, through

connector elements

30 and 31, and into production tubing strings 20 and 21. The procedure for circulating tools and instruments through a wellhead assembly of this type, i.e. a Y- branched wellhead assembly, is more clearly set forth in the above-noted US. Patent No. 3,064,735. If desired, suitable manipulations may be carried out through tubing runs 51 and 52 to close down the well and remove all or a portion of the wellhead assembly 25 to the surface along

guidelines

71 and 72 to perform suitable maintenance or other operations. US. Patent No. 3,064,735 also describes an arrangement for effecting the removal of a wellhead assembly to the surface of a body of water for this purpose. It should be noted that upon retrieval of the wellhead connector 44 to vessel 11, integrally connected guideline carrying means 46 and 47 cooperate with

top plates

69 and 70, respectively, to also remove to the surface

tubular members

65 and 66 along

guidelines

71 and 72, The guidelines, as is readily apparent, permit apparatus of any desired type to be conveyed quickly back and forth between vessel 11 and the well site.

I claim as my invention: 1. Apparatus for making a remote connection between a subsurface production wellhead assembly and a floating vessel on the surface of a body of water, said apparatus comprising first means positioned on the floor of the body of water and second means lowerable from said vessel into engagement with said first means, said first means comprising:

base assembly means under said body of water and fixedly positioned with respect to said wellhead assembly; guide column means included on said base assembly means and extending in a substantially upward direction; said second means comprising:

pipe means operatively associated with said vessel and having one free end and one end held in operative engagement by said vessel; wellhead connector means afiixed to said pipe means at the end of the pipe means remote from the vessel; frame means depending from said Wellhead connector means; guideline connector means depending from said frame means; guideline means extending from said vessel and being operatively attached to said guideline connector means; cooperating orienting means having first and second portions, the first portion being carried by said wellhead assembly and the second por tion being carried by said wellhead connector means, said cooperating orienting means being adapted to operatively position said wellhead connector means with respect to said wellhead assembly and position said guideline connector means with respect to said guide column means so that operative engagement between said guideline connector means and said guide column means may be effected.

2. The apparatus according to claim 1 wherein said portions of said cooperating orienting means comprise a guide slot and a pin element cooperable therewith.

3. The apparatus according to claim 1 wherein saidv wellhead assembly includes conduit means and one of said portions of said cooperating orienting means is operatively associated with said conduit means while the other of said portions is operatively associated with said wellhead connector means.

4. The apparatus according to claim 1 wherein said Wellhead assembly includes a plurality of radially pro- 8 5. Apparatus for making a remote connection between an offshore wellhead assembly beneath the surface of a body of water and a remotely-located floating vessel on the surface of the body of water, said apparatus comprising:

base assembly means underlying said water and fixedly positioned with respect to said wellhead assembly, said base assembly means including guide column means extending in a substantially upward direction;

pipe means depending from said vessel and having Wellhead connector means afiixed thereto at the end of said pipe means remote from said vessel;

guideline connector means depending from frame means on said pipe means, said guideline connector means having guideline means operatively associated therewith;

cooperating orienting means on said wellhead assembly and on said wellhead connector means for operatively positioning said wellhead connector means on said wellhead assembly and for substantially simultaneously bringing said guideline connector means into position with respect to said guide column means whereby operative engagement may be effected therebetween;

means for locking said wellhead connector means to said wellhead assembly after said orienting means has operatively positioned said wellhead connector means on said wellhead assembly; and

said guideline connector means comprising latching means on said guideline means for effecting attachment between the guideline means and said guide column means after said wellhead connector means has been locked to said wellhead assembly and said guideline connector means has been brought into engagement with said guide column means.

6. The apparatus according to claim 5 wherein said wellhead assembly includes upstanding conduit means to which the wellhead connector is locked; said conduit means being normally closed at its upper end by end closure means through which a portion of said connector selectively protrudes.

7. The apparatus according to claim 6 where in said end closure means comprises at least one circular disc constructed of resilient material and including a plurality of independently movable wedge members.

References Cited UNITED STATES PATENTS 3,062,287 11/1962 Hayes l66.5 3,163,228 12/1964 Hayes l66.5 3,179,176 4/1965 Goepfert 7 X 3,236,302 2/1966 Postlewaite 175-7 X 3,316,984 5/1967 Jones 1757 3,322,193 5/1967 Word l66.6 3,353,595 11/1967 Nelson et a1. l66.6

FOREIGN PATENTS $34,492 3/ 1958 Germany.

CHARLES E. OCONNELL, Primary Examiner RICHARD E. FAVREAU, Assistant Examiner US. Cl. X.R. 175-7