US3166123A

US3166123A - Method and apparatus for underwater wells

Info

Publication number: US3166123A
Application number: US197093A
Authority: US
Inventors: Bruce J Watkins
Original assignee: Shell Oil Co
Current assignee: Shell USA Inc
Priority date: 1962-05-23
Filing date: 1962-05-23
Publication date: 1965-01-19
Anticipated expiration: 1982-01-19
Also published as: GB982070A

Description

Jan. 19, 1965 METHOD AND APPARATUS FOR UNDERWATER WELLS Filed May 23, 1962 5 Sheets-Sheet 1 INVENTOR BRUCE J. WATKINS IS AGENT Jan. 19, 1965 B. J. WATKINS 3,166,123

METHOD AND APPARATUS FOR UNDERWATER WELLS Filed Ray 23, 1962 5 Sheets-Sheet 2 INVENTOR BRUCE J. WATKINS H r. g

HIS AGENT Jan. 19, 1965 B. J. WATKINS 3,166,123

METHOD AND APPARATUS FOR UNDERWATER WELLS Filed Bay 23, 1962 5 Sheets-Sheet 3 INVENTORZ BRUCE J. WATKINS BY- H uQ AGENT Jan. 19, 1965 B. J. WATKINS 3,166,123

METHOD AND APPARATUS FOR UNDERWATER WELLS Filed May 23, 1962 5 Sheets-Sheet 4 I NVENTOR BRUCE J. WATKINS HI 5 AGENT 'Jan. 19, 1965 B. J. WATKINS 3,166,123

METHOD AND APPARATUS FOR UNDERWATER WELLS FIG. I5

FIG. l4

INVENTOR:

BRUCE JV WATKINS HIS AGENT United States Patent Gfiice 3,166,123 Patented Jan. 19., 1965 This invention relates to operations to be carried out on underwater wells, and pertains more particularly to a method and apparatus for connecting a vessel floating on the surface of the water to an underwater wellhead assembly of an oil or gas well. I r

A relatively recent development is the drilling of oil and gas wells at offshore locations wherein the wellhead assembly is positioned at a substantial distance below the surface of the water or on the ocean floor. During the drilling and completion of a well of this type suitable provisions are made for maintaining contact between the vessel on the surface of the water and the underwater wellhead, as by means of a plurality of guide lines or one or more elongated pipe strings. Using guide lines or a pipe string between the vessel and the ocean floor, the

well may be drilled and all the necessary equipment lowered into place on top, of the wellhead. When the well has been completed the guide lines extending to the vessel are disconnected from the vessel and eitherrdropped to the ocean floor or secured to a buoy which marks the location of the well.

The use of buoys to mark .a well orto support guide 7 lines is not desirable since they constitute a navigation hazard and may break free from the cables. Additionally, the dropping of guide lines'to the ocean floor is not too satisfactory since the lines often become entangled and are subject to corrosion. However, it is necessary to mark the well in some manner or be able to locate it r so asto go back over the well with the vessel for the necessary work-over operations that must be carried out on all wells from time to time. t

It is therefore a primary object of the present inven-' tion to-provide a method and apparatus for establishing a connection between a vessel on the surface of a body a of water and a wellhead assembly positioned at a distance to a point adjacent an underwater wellhead structure and for guiding and aligning the lower end of the elongated tubularmember into its seating position on the wellhead assembly. 3

A further'object of the present invention is to provide a method of establishing connection between a vessel and underwater wellhead by means of an elongated element whereby equipment used in work-over operations on the well may slide down the elongated guide element into position on the wellhead assembly.

A still further object of the present invention is 'to' provide apparatus for securing the lower end of a cable or wire line to a wellhead assembly. I i

These and other objects of this invention will be understood from the following description taken with reference to the'drawing, wherein: I

FIGURE .1 is a diagrammatic view illustrating the op ,eration of lowering a cable from a vessel at the surface of the water to a wellhead positioned near the ocean floor;

FIGUREZ is a diagrammatic view of the vessel and wellhead assembly of FIGURE latter a guide cable has been attached to the wellhead and a string of pipe is being lowered down along the guide cable;

FIGURE-3. is a longitudinal view taken partially in cross-section'of a hook-type cable connector secured to an element of an underwater wellhead assembly; 7

FIGURE 4 is a longitudinal view taken in partial cross section of the hook-type cable connector of FIGURE 3 secured to a power wrench adapted to be lowered to an underwater wellhead assembly;

FIGURE 5 is an isometric view of one portion of the hook-type cable connector of FIGURE 3;

FIGURE 6 is a diagrammatic view illustrating a clawarm of an underwater manipulator secured to a cable hook; I

FIGURE 7 is a diagrammatic view illustrating a tubular pipe element being lowered from a vessel-at the surface of a body of water with an underwater manipulator guiding the lower end of the tubularfelement onto the top ofan underwater wellhead assembly; V v

FIGURE 8 is adiagrammatic view illustrating a marine conductor pipe being lowered from a vessel at'the surface of a body of Water oyer a small-diameter pipe string having its lower end connected to a wellhead at the ocean floor;

FIGURE 9 is a longitudinal view taken in partial cross-section of a landing head of ;a marine conductor string; Z V o FIGURE 1Q-is a longitudinal view illustrating a-portion of the la nding head assembly of FIGURE 9 together with another form of a cable connector being guided by an arm of an underwater manipulator into position to connect to a wellhead assembly;

FIGURE 11 is a longitudinal view taken partially in cross section and in enlarged detail of the cable connector of FIGURE 10 when locked to a receiving sleeve on the wellhead assembly; V j a v I FIGURES 12 and 13 are plan views of -two types. of connectors for securing an underwater manipulator to a small-diameter pipe-string;

FIGURE14 is a diagrammatic view of an underwater wellhead assembly showing the lower end' of a guide element being secured thereto; and

FIGURE 15 is a longitudinal view taken in partial cross section of the cable connector-of FIGURE .14 and the manner in which it is secured to'the power wrench of the underwatermanipulator.

Referring to FIGURES 1 and 2 of the drawing, a drilling barge 11, of any suitable floating or floatable type is illustrated as floating on thesurface of the water 12 while being substantially fixedly positioned over a ,pre-

selected well location by being anchored to the :ocean floor 13 by anchor lines 14 and 15 running tov anchors (not shown). Equipment of this type may be used when carrying on well drilling operations orwell, work-over operations in water varyingfrom about feet to 1500 feet or more. The barge or .vesselll is equipped with a suitable derrick 16' containing a fall line system 17 (FIG- The vessel 11 is also'provided with other. auxiliary equipment needed during well operations, such for example as .a'rotary table positioned on the operat- URE 2).

0 .SHORAN 'or other similar position-finding systems wll knowntotheart.

The underwater wellhead structure illustrated in FIG- 'andS'erial No. 80,275, filed January'3, 1961. I 'nipulator device comprises a body member 36 having means such as wheels 37 for'securing it to' the Wellhead URES 1 and 2 is similar to that which isassembled dur- I 7 ing' the drilling and completion of an underwater well in accordance with the method described in copending application, Serial No. ll8,849, filed June 22, 1961. The

wellhead assembly includes a large-diameten'conductor or foundationpile which is secured in the well by means ofv cement 21." p The' upper end of the wellhead assemblyhas a casinghead 22 closed by 'a production production T 25 above the master valves 24 is adapted to receive a pair of flow lines 26and 27. A pair of swabbing" valves 28 are mounted above the production T 25 and the'top of the well is closed by means of a lubricator barrel 29 and a plug 30. The top of the plug 30 is provided with a fishinghead 31 by which it 'rnay be readily removed.

Fixedly secured to the foundation pile'20 near the top thereof is a track 32 which extends around the foundation pile While b ing positioned outwardly thereof.

As shown in FIGURE 2, the track 32 is adapted to receive and hang therefrom an underwater manipulator device which is self-propelled at leasttin a horizontal diare shown in" copending patent applications, Serial No. 24,558, filed April 25, 1960,'now Patent No. 3,099,316,

The maassembly, that is, to the track 32 in this particular illustration. The wheels 37 are preferably actuated by motor means operatively connected to the wheels and positioned either inside or' outside the body member 36; Additiona-l'ly, the body member 36 is preferably providedwith a pair of idler rollers 38 mounted on an'outwardly-extend- "ing frame 39 so as to contact the outer'surface of the foundation pile '20, as shown in FIGURE 2, when the drive wheels 37 are hung on the track :32; Alternatively, the rollers 38 could be powered to makefriction contact 'with the outer surface of the foundation pile to drive the manipulator device 36 around the wellhead assembly.

A portion of the body member is arranged for upward,

extension from the body member, preferably in the form i of a telescoping arm 40, as shown in FIGURE .2.

Mounted on the top of the telescopingarm or body portion 40 is a laterally-extending cylinder 41 7 having' a telescoping arm 42 extendible outwardly therefrom. -The arm 42 is provided with a rotatable wrench head 43 that is power operated by suitable motor means mounted in the arm 42 or in the cylinder 41,'preferably in the rear portion 44 thereof. VA television camera 45 and suitable lights 46 are mounted at the top off'the manipulator device on a power-actuated light swivel and tilting mechanism 47, whilethe television viewing screen is positioned on the vessel 11: at the surface. 7

The manipulator device 35 may be suspended on a hook a 4 In FIGURE 1 the vessel 11 is shown as having been positioned over the wellhead assembly, generally represented by numeral 19, and the manipulator device 35 has been lowered to a level to one side of the wellhead assem- 'bonnet 23 on. which the mounted maste valves 24. A

50having a weight-supporting and current-transmitting cable 51 attached to its upper end. Thus, power for operating the manipulator device and its associated equipment is sent down the cable 51 from the vessel 11 while television signals are returned up the cable to the vessel.

At the same. timethe manipulator device may be lowered from the vessel 11 by means of the; cable 51 and its hoist to any selected level in the water. For moving the manipulator device 35 laterally at the end of the cable 51,'the manipulator device 35 is provided with suitable propulsion means such, for example, as motor-driven pro pellers 52a which are mounted outboard of the body member 36 on at least two sides thereof. 1 At least a portion of {the'body member 36 may forma void chamber which may be selectively flooded by controls at the vessel 11 for adbly and just above the point where the wheels 37 would sit on the track 32 of the wellhead assembly. Prior to lowering the manipulator device ,35 from the vessel 11, a

' hook or other suitable connector device 52 was secured to the wrench head 43 of the manipulator device 35. tached to the upper'endof the hook 52' is a wire line or cable 53 which is to serve as the guide line connecting the vessel ll-to the wellhead assembly 19 during at least a portion of the work-over. operations on the well. Fixed* 1y secured to some portion of the wellhead assembly 19 is a bracket ring'or other cooperating connector-device 5410 which the hook 52 may be connected.

In'FIGURE 2, the hook 52'is illustrated as having been connected to the bracket 54 while the'wrench head 43 of the manipulator device 35 has been disconnected from the hook 52 so that the manipulator device could be moved awayfrom the wellhead assembly at any time. However, the'-manipula'tor'device is left' in place so that a television camera 45 can observe the top of the wellhead assembly as a marine conductor pipefstring 56 and its landing head'57 are guided down along the guide line 53 onto the lubricator 29 of the wellhead assembly. The landing head or man-' drel 57 isslidably mounted on the guide line 53 by means of a sleeve 58. Y a

a The bracket 54 which is shown as fixedly mounted to the wellhead assembly in FIGURES l and 2 is shown in FIGURE S'as-having an opening 55 therein so that a portion 54a of the bracket can fit within a hook orother connector element. i

A preferred form' ofcable hook 52 .(FIGURE 1) is shown in FIGURE 3 as having a throat opening 61 of a size to receive'a portion 54a of the bracket'54. The shank 3 62of thehook 52 has a boss 63 extending away from the throat opening 61. A- laterally-extending lockingscrew 64 is mounted in the boss 63 with a forward end 65 of the screw 64' adapted to close the throat opening 6170f the p book 52. The head 66 oftthe screw 64 is adaptedto 'be received in the. recess 67 of the socket wrench 43'; The socket wrench 43 is mounted at the end of a power-driven shaft 68 which extendible out the end of the arm 42.

llntegrallyformed ,on the back-end ofthe boss 63 is a I .smtable locking bracket 70. which supports an end plate 71 having a vertical opening 72 therein (FIGURE 5) of a size at least slightly wider than the diameter of the stem or shaft of the wrench head 43. 'Formed on the inner face of the end'plat e 71 is a recess'73 which surrounds the lower end of the vertical opening or slot 72.. The recess 73 is of -a size slightly larger than the rear end ofthe wrench headi43 so that it can'be received therein asshown in FIGURE 4. In FIGURE 4 the hook 52 is shown in its open positionwith the locking screw 64 retracted a dis tance so that' the screw head 66 is firmly seated in the socket wrench 43 while the socket wrench in turn is securely seated in the recess 73 of the bracket In this position the hook 52 is securely carried in a removable manner attheend of the arm 42 when it is desiredto move the cable down through the water.

The'cable'53 (FIGURE 3) is secured tothe shank 62 of the book 52 by any suitable. type of cablesocket 74,

preferably one which fails under a predetermined tension, say 8,000 pounds; so that the cable 53 may be pulled away from the hook52 in an emergency InFIGURE 6' another type of hook isshown which is provided with a retractable;spring-loaded catch 76' which would prevent the-hook 'from falling olf a bracket to which itwas attached. The cable 77 to the hook 75 woul d betsecured to the hookiby means of a cable 7 8 which would fail under. a predetermined tensionfi. Fixedly secured to the outside of the cable socket 78 are one ormore rings 79 and 80 the manipulator device 35 of FIGURE 1. The claw arm 81 would be mounted at the end of a cylinder 82 opposite to the cylinder 41 which held arm 42 and wrench socket 43 in the manner described in copending application, Serial No. 24,558, filed April 25, 1960. Thus, it may be seen that a cable hook may be run down through'the water either by being attached to the manipulator 52 by the wrench socket 43 or by claw arm 81. r,

In practicing the method of the present invention to connecting a guide line cable between the vessel on the surface of the body of water and a wellhead assembly positioned at a distance below the surface of the water, the vessel 11 (FIGURE 1) would first be positioned substantially over the underwater wellhead assembly 19. The hook 52 at the lower end of theguide line 53 would then be secured to the manipulator device 35, as in a manner illustrated in FIGURE 4 wherein the. socket wrench is seated in the recess 73 of the bracket 20 so that the hook 52 is fixedly secured to the arm 42. The manipulator device 35 is then lowered on its support cable 51 from the barge where the cable 51 is secured to a suitable-hoist drum or other cable-storing device (not shown). With the weight of the manipulator device being supported by the cable 51, the manipulator device 35 together with the hook 52 and its guide line 53 are lowered through the water to a position adjacent the wellhead assembly 19 (FIGURE 1). While observing the wellhead assembly by means of the television camera 45, the propellers 52a of the manipulator device 35 are driven to propel the manipulator device against the wellhead assemblywith sufiicient cable 51 being let out at the vessel so ;as to lower the wheels 37' of the manipulator device on the track 32.

With the manipulator device 35 seated on the track 32 (FIGURE 2), the telescoping vertical arm or body portion 40 of the manipulator device is raised and the laterally-extending arm 42 at the end thereof is moved to, engage the hook 52 in the bracket 54 secured to the wellheadassembly 19. The power wrench and the arm 42 are then actuated so that the socket wrench movesthe locking tending the telescoping arm 40, as shown in FIGURE 2.

With the guide cable 53 securely locked to the wellhead assembly 19, as shown in FIGURE 2, a conductor pipe 56 and its landing head 57 may be guided from-thevessel the guideline 53 (FIGURE 2) passes may be secured ti) assembly, at which point the'arm 42 of a manipulator device aligns the lower end or seating-socket 93 of the pipe string on the top of the wellhead 19. The pipe string 92 may be any suitable type 'of pipe, "preferably in the form of 30-foot sections that are connected together at the vessel before they are lowered .into' the water. The connecting element 94 carried at the end of the arm 42. ofthe manipulator device may be in the form of grab arms 81 (FIGURE 6) or any other suitable hook or connector device Additionally, when it is desired to align the lower end of a pipe string92 for stabbing it on the top of a tubular element of'awellhead, the connector device 94 of the manipulator device may be loosely secured to the 'pipestring, 92 so that it can slide vertically down over the pipe as the manipulator device is lowered through the water. Thus, substantially the entire pipe string would first-be made up sectiontby section and lowered into the water prior to lowering the manipulator device onits support cable 51 down to the lower end of the .pipe string -92. As in the case of securing a cable. to the underwater wellhead, it is' preferred that'the manipulator device 35 beseated on its track 32 as shown in FIGURE 2, at the time: the pipe -line'-'92. is lowered onto ,a tubular element of the wellhead assembly. However, it is to be understood thatthe manipulator device 35 may be propelled by its propellers 52a throu'gh' thewater-to a position adjacent 'the'wellheadassembly and 'to align the lower end of'the pipeIstring 92 'or to into alignment and down on the top' of thewellhead as- V sembly 19 byslidably mounting the landing 'head- 57 to the guideline 53 by means of a sleeve'58. Seating of the 1 landing head 57 on top of the wellhead is either aidedby the television camera or may be carried out bya blind stab, that is by stabbing on --top of the wellhead and if necessary rotating the marine conductor around the guide line 53 until the landing head 57 has been successfully stabbed over the top of the Wellhead assembly 19. As an alternative, two guide lines 53 can be attached to better align to landing head 57. V 7

One form of a marine conductorpipe 56 on the landing head 57 of FIGURE 2 isshown in FIGURE 9 wherein the landing head comprises a body member 84 having a vertical bore therein of a size to receive the top of a tubular well member. Carried within the body member 84 and surrounding its bore 85 is a bag-type sealing element 86 which may be compressed tosealaround an object in connect the hook'52 on bracket-54- (FIGURE 2) without seating the manipulator device 35 on its track 32;;

FIGURE 8 the pipe string 92 is-shown as having been seated on the top of the lubricator 29 at the top 0f the well assembly witha marine conductor pipe-56 V on the 1ubricator-29, pressure fluid will :be applied through conduit 87 which extends downwardly fromJthe vesseltll to actuate the seal 86. (FIGURE 9) lot the landing head against the lubricator 29.

. -One s'uitable type of pipeconnector for= securing the pipe to the arm. 42 "of fthe-manipulator device is shown in FIGURE 12; The'pipe'connectoris essentially 'a hook 96 having a throat opening'97 'of a size gre'aterthan the diameter ofthe pipe string 92fi toabe' received. therein. The, throat 97 ofthe hook 96 is closed in any suitable manner, as by a screw 98 which is threaded in a boss 99. I

A bracket Unattached to the boss 99 has an end' piece 102 with an -opening 103 therein for receiving the shaft 68 to the socket "wrench 43. The pipe connector, when used, issecured to the pipe string 92 and .to .the wrench socket 43 prior to lowering the pipe string .infthe water. After the lower end of the pipe stringvhas been seated' on the wellhead assembly, the wrench socket 43' of the power Another form of a pipe hook is shown in -FIGURE .13

as comprising a hook 105 having anopen throat 106 that maybe partially closed by means of a pipe-engaging element 107 whichiis slidablymounted in a recess 108 in in, the .inner surface of the hook 105 and the pipe. con

tacting. face of thezpipe engaging element 107 may be provided with teeth or serrated elements-113 and 114 which would frictionally engage'the outer surface of a pipe positioned in the hook 105 when the pipe-engaging element 107 was closed against it. When a .pipe element having pipezhook 105 attached theretohas'been seated at the wellhead, the socket wrench 43 may be withdrawn from the extending sleeve 115 of boss 109 with the hook 105 being left-on the. pipe, at the wellhead while the manipulatordevice is taken away. Alternatively, the

socket wrench 43 may beactuated. to retract the screw 111 and pull the pipe-engaging element 107 back into the recess 108a: which time the hook 105 could be removed from. the. pipe by rotation of the arm 42 in a plane normal to .the axis of the pipe, If desired, the socket wrench'43 may be secured .to the head 112 of thescrew "111. in a manner described with regardto :FIGURE 15 hereinbel'ow; a V In another. form of the present invention, a connection may be made between a vessel at the surface of the water and an underwater assembly when using a stab-type con- 7 hector adapted to pass at' least partially through an'element of the underwater wellhead ,assemblyghaving an opening therein..: While the bracket 54-(FIGURE' 3) havinga hole 55 therein .may-be employed,.a sleeve 117 (FIGURE 10) which is conneCtcdtOthe wellhead structure 19may be employed. In this case the lower end of a guide cable 118 is provided' with a connector having a body element 1190f a size sufiicient topass through the .sleeve 117.- A pair of radially-extendible latching dogs 120 and 1213are' provided with a pair of ring'elements. 122 .and 123 .which would prevent a ,claw arm 81 of the manipulator device or any other suitable connector 'means from slipping off the body member .119 when the body member and its; cable 118 werelowered through the 7 water to the wellhead assembly. r

As shownin FIGURE 11, the latching dogs 120 121 are'pivotally. secured in a slot 124 in the body memher by means of a pin 125.- The latching dogs 120 and 121 are readily'retracted to their inoperative position within the. body member 119 whenthe body member is lowered through the sleeve 117 .and-the latchingdogs con- :tact the upper edge of the sleeve. However, the latching dogs-120 and 121are normallyurged upwardly by means 4 of a pistonmember. being urged downwardly byacompression spring 127. The. latching dogs .120 and"121.are normally. maintained: in a horizontal position by

shear pins

128 and 129 which mayv be selected to shear at any desired tension on the cable 118 (FIGURE 10).

Thus, when the guide line 118 is, no longerto be used, an excessive upward pull on the. guide line would cause shear pins 128 and.129 (FIGURE 11) .to shear and the latching

dogs

120 and 121 wouldipivot, downwardly into the slot 124 so that the body member 119 could be pulledout of the sleeve 117. r

Instead of employing connectors atthe lower end of a guide cable of the type 'describedhereinabove, the Com nector may include a screw element 131 which may be directly connected to the. wellhead assembly 19, Thus,

' in FIGURE 14an-arm 42 and its'socketwrench 43 are shown as being connected to a screwmember 131 which is attached to the lower end of a cable or guide line 133 by means of any suitable cage member..134.' The end "plate 135 of the cage 134 .is preferably in the form of the end'pla'te 71 shown in FIGURE 5 so that the socket wrench 43 can be lifted out of the cage 134 after the 'to which thecable rod or tubular member is to be attached a maynot be fixedly secured to the ocean .floor but may be movably positioned below the surface of the water with- 8 screw-has beenrun into thewellhead assembly 19. In FIGURE 15 the cable 134 is secured by means'of a cable socket 136 to a ring 137 which is rotatably mounted between

shoulders

138 and 139 on a screw 140. .The head 141 of the screw ,140 is carried within a socket wrench 143 which is provided with one or more spring-loaded plugs or

detent members

144 and 145 which are adapted to seat in a circumferential groove 146 in the head of the screw-140.. Thus, in running a cable 134 down to an underwater wellhead assembly, the screw head 141 would be seated in the wrench socket 143 so that the

detents

144 and 145 would hold it there during the time that the screw was being runldown to the wellhead and secured to the Wall thereof. head the socket wrench would then be pulled axially away from the screw head 141 and the manipulator devicecould be returned to the'surface.

While the present invention has been described with regard to running an elongated tubular member, rod ,or cable betweena vessel 'and' a wellhead assembly positioned beneath the surface of the water, it is .to be understood that the apparatus and method of the present invention could also be employed to run or lower and subsequently connect any elongated element from any operating platform or vessel'above the surface of the water down to any underwater installation such for example underwater storage tanks, pipelines, oil production handling facilities, waste disposal Wells, etc. In some instances, such for example as underwater oil storage facilities and production handling stations, the station or assembly in a certain area. Also, the guide cable installedby the lower equipment to carry out certain functions at the wellhead, as for example, adjusting the setting of wellhead components, opening or closing valves, connecting a flowline to the wellhead, etc.

In'carrying out the method of the present invention it is to be understood that the vessel at the surface of the water need not be anchored by. anchor lines but may alternatively be positioned by a series of two or more op- -posing outboard motors.

example as a SONAR system which is well knownto. the. art, whichsystem may be used as a substitute for or in addition to the television camera. Since the manipuilator device 35 may be equipped with buoyancy tanks which may be selectively flooded by controls on the vessel '11, itis understood that the'manipulator device maybe lowered through the water by' selectively flooding the buoyancy tanks to cause the manipulator deviceto sink slowly 'to'a selective position adjacent an underwater in-. stallation.

The method of the present invention may also be carried out by lowering the manipulator device and the flexible connector element, that is, either a cable or pipe string, independently through the water into the vicinity of the wellhead structure. The manipulator device by means ofits television apparatus would then locate the flexible connector element and secure itsarm to the lower end thereof, after which the manipulator device 1 would propel both itself and the flexible connector unit into position for attachingthe. lower end of the flexible the top of the wellhead either before or after the plug 30 has been removed. Alternatively, with plug 30 removed the connector 119 could be lowered into the top of the wellhead to engage a latch surface and secure cable 118 With the cable secured to the welli to the wellhead so that equipment could be stripped over or guided along the cable.

I claim as my invention: a

l. A method of establishing a connection between a vessel on the surface of a body of water and an assembly positioned at a distance below the surface of water, said method comprising (a) positioning said vessel substantially over said underwater assembly,

(b) removably mechanically attaching one end of an elongated connector elementtoa self-propelled submersible manipulator,

(c) lowering said manipulator and said attached elongated connector element in said body of water,

(d) simultaneously increasing the length of said elongated connector element as it is lowered through the water with the manipulator so that the upper end of sm'd elongated connector element is above the surface of the water,

(2) locating the underwater assembly with a television camera carried by the manipulator and observing on the vessel at the surface the position of the underwater assembly relative to the manipulator,

(f) remotely moving and guiding from the vessel the manipulator and the attached elongated connector element through the water to a position adjacent said assembly,

(g) positioning the manipulator in movably supported contact on said assembly,

(11) positioning the lower end of the elongated connector element in contact with said assembly,

(i) remotely actuating the manipulator from the vessel to attach the lower end ofthe elongated connector element to said assembly, and

(j) mechanically remotely actuating the manipulator from the vessel to disconnect the manipulator from the elongated connector element attached to the assembly.

2. The method of claim 1 including the steps of (k) guiding the lower end of a large-diameter pipe string along the elongated connector element while lowering it from the vessel,

(l) telescopically connecting the lower end of the largediameter pipe string to a mating portion of the assembly, and

(m) subsequently raising the manipulator to the vessel at the surface.

3. A method of establishing a connection between a' vessel on the surface of a body of water and an underwater wellhead assembly positioned at a distance below the surface of water, said method comprising (a) positioning said vessel substantially over said underwater assembly,

(b) lowering an elongated connector element from the a vessel down through the water until the lower end of the connector element is in the vicinity of the wellhead assembly,

(0) removably and slidably attaching near the upper end of said elongated connector element a selfpropelled submersible manipulator at a point above the surface of the water,

(d) lowering said manipulator through the water while sliding along said elongated connector element to a point near the lower end thereof,

(e) locating the underwater wellhead assembly with a television camera carried by the manipulator and observing on the vessel at the surface the position of the underwater assembly relative to the manipulator,

(f) remotely moving and guiding from the vessel the manipulator and the attached elongated connector element through the water to a position adjacent said wellhead assembly,

(g) positioning the lower end of the elongated connector element in contact with said wellhead assembly, and

(h) remotely actuating the manipulator from the vessel element to said wellhead assembly. 4. The method of claim 3 including (i) disconnecting the manipulator from elongated connector element attached to the wellhead assembly, and

(j) subsequently raising the manipulator to the vessel at the surface.

5. The method of claim 3 including the steps of (i) subsequently sliding the manipulator device up the elongated connector element to the surface of the water and (j) disconnecting the manipulator fromsaid elongated connector element.

6. A method of establishing a connection between a vessel on the surface of a body of water and an underwater wellhead assembly positioned at a distance below the surface of water, said method comprising (a) positioning said vessel substantially over said underwater assembly,

(b) removably attaching one end of an elongated fiexible cable to a self-propelled submersible manipula- (d) simultaneously increasing the length of said cable and cable element as they are lowered through the water with the manipulator,

(f) remotely moving and guiding from the vessel the manipulator and the attached end of said flexible cable through the water to a position adjacent said wellhead assembly, i

(g) positioning the manipulator in weight-supporting engagement on said wellhead assembly,

(h) remotely actuating the manipulator from the vessel to attach the lower end of the flexible cable to said Wellhead assembly,

(1') remotely actuating the manipulator from the vessel to disconnect the manipulator from flexible cable attached to the wellhead assembly, and I (j) subsequently raising the manipulator by its cable element to the vessel at the surface.

7. The method of claim 6 wherein the lowering of the manipulator takes place by selectively adjusting the buoyancy of the manipulator to cause it to sink to the vicinity of the wellhead assembly.

8. A method of establishing a connection between a vessel on the surface of a body of water and an underwater wellhead assembly positioned at a distance below the surface of water, said method comprising (a) positioning said vessel substantially over said underwater assembly,

(b) removably attaching one end of an elongated flexible pipe string to a self-propelled submersible manipulator at a point above the surface of the water,

(c) lowering said manipulator and said attached flexible pipe string in said body of water at the end of a weight-supporting cable element, a

((1) simultaneously adding sections of pipe to the upper end of said flexible pipe string as it is lowered through the water by the manipulator so that the upper end of aid pipe string is above the surface of the Water,

(f) remotely moving and guiding from the vessel guiding from the vessel the manipulator and the attached pipe string through the water to a position adjacent said wellhead assembly,

(g) positioning the manipulator in movably supported contact on said wellhead assembly,

(h) remotely actuating the manipulator from the vessel to attach lower end of the flexiblepipe string to said Wellhead by lowering the connector element from the surface to engage telescopically a portion of said wellhead assembly, and

(i) remotely actuating the manipulator from the vessel to disconnect the manipulator from flexible pipe string attached to the wellhead assembly.

9. A method of establishing a connection between a 'vessel on the surface of a body of waterand an underwater wellhead assembly positioned at a distance below the surface of water, said method comprising (a) positioning said vessel substantially over said underwater assembly, 7 (b) lowering a self-propelled submersible manipulator and a flexible connector element independently through said body of Water tothe vicinity of the wellhead assembly, (c) locating the lower end of said connector element with said manipulator,

(d moving the manipulator to said connector element and mechanically connecting it to the lower end thereof, I

(e) locating the underwater wellhead assembly with the manipulator, a

7 (f) moving and guiding the manipulator and the attached flexible connector element through the water to said wellhead assembly, and V (g) attaching the lowerend of the flexible connector element to said wellhead assembly. 10. Apparatus for establishing a connection between a vessel on the surface of a body offwater and an underelongated guide pipe and adapted to be carried bysaid manipulator and lowered through the water therewith, (e) cooperating means on said manipulator for removably securing said connector means thereto, and (f) remotely-controlled actuator means operatively connected throughsaid cable means to said vessel and carried by said'manipulator and engageable with connector means for removably attaching said connector means to said underwater assembly.

References Cited by the Examiner UNITED STATES PATENTS 1,324,425 12/19 Long 61-69 1,378,843 5/21 Drake 6l-69 1,777,184 9/30 Stamper 6l--69.l 1,785,528 12/30 ,ORourke 6169.1 2,909,359' 10/59 Bauer etal -7 3,032,105 5/62 Reistle 16646 3,032,125 5/62 Hiser et al, 175+7 3,099,316 7/63 Johnson 166--66.5 X

CHARLES E. OCONNELL, Primary Examiner.

Claims

1. A METHOD OF ESTABLISHING A CONNECTION BETWEEN A VESSEL ON THE SURFACE OF A BODY OF WATER AND AN ASSEMBLY POSITIONED AT A DISTANCE BELOW THE SURFACE OF WATER, SAID METHOD COMPRISING (A) POSITIONING SAID VESSEL SUBSTANTIALLY OVER SAID UNDERWATER ASSEMBLY, (B) REMOVABLY MECHANICALLY ATTACHING ONE END OF AN ELONGATED CONNECTOR ELEMENT TO A SELF-PROPELLED SUBMERSIBLE MANIPULATOR, (C) LOWERING SAID MANIPULATOR AND SAID ATTACHED ELONGATED CONNECTOR ELEMENT AS IT IS LOWERED THROUGH THE (D) SIMULTANEOUSLY INCREASING THE LENGTH OF SAID ELONGATED CONNECTOR ELEMENT AS IT IS LOWERED THROUGH THE WATER WITH THE MANIPULATOR SO THAT THE UPPER END OF SAID ELONGATED CONNECTOR ELEMENT IS ABOVE THE SURFACE OF THE WATER, (E) LOCATING THE UNDERWATER ASSEMBLY WITH A TELEVISION CAMERA CARRIED BY THE MANIPULATOR AND ABSORBING ON THE VESSEL AT THE SURFACE THE POSITION OF THE UNDERWATER ASSEMBLY RELATIVE TO THE MANIPULATOR, (F) REMOTELY MOVING AND GUIDING FROM THE VESSEL THE MANIPULATOR AND THE ATTACHED ELONGATED CONNECTOR ELEMENT THROUGH THE WATER TO A POSITION ADJACENT SAID ASSEMBLY, (G) POSITIONING THE MANIPULATOR IN MOVABLY SUPPORTED CONTACT ON SAID ASSEMBLY, (H) POSITIONING THE LOWER END OF THE ELONGATED CONNECTOR ELEMENT IN CONTACT WITH SAID ASSEMBLY, (I) REMOTELY ACTUATING THE MANIPULATOR FROM THE VESSEL TO ATTACH THE LOWER END OF THE ELONGATED CONNECTOR ELEMENT TO SAID ASSEMBLY, AND (F) MECHANICALLY REMOTELY ACTUATING THE MANIPULATOR FROM THE VESSEL TO DISCONNECT THE MANIPULATOR FROM THE ELONGATED CONNECTOR ELEMENT ATTACHED TO THE ASSEMBLY.