US3424242A

US3424242A - Method and apparatus for drilling offshore wells

Info

Publication number: US3424242A
Application number: US652756A
Authority: US
Inventors: William C Triplett
Original assignee: Chevron Research and Technology Co
Current assignee: Chevron USA Inc
Priority date: 1956-12-03
Filing date: 1957-04-15
Publication date: 1969-01-28
Anticipated expiration: 1986-01-28

Description

Jan. 28, 1969 vv. c. TRIPLETT 3,424,242

METHOD AND APPARATUS FOR DRILLING OFFSHORE WELLS Filed April 15, 1957 sheet of e irl 'IMI

INVENTOR W/L/AM c. TR/P/.ETT

Jan. 28, 1969 W. c. TRIPLETT 3,424,242

METHOD AND APPARATUS FOR DRILLING OFFSHORE WELLS Filed April 15, 1957 Sheet i of 6 Jan. 28, 1969 w. c.TR||=LETT 3,424,242' l ME'ODv AND APPARATUS FOR DR/ILLING OFFSHORE WELLS I Filed April 15, 1957 sheet 3 of e Jan. 28, 1969l w. c. TRIPLETT 3,424,242

METHOD AN APPARATUS FOR DRILLING OFFSHORE WELLS Filed April l5, 1957 Sheet 4 of' 6 law/M F|G.11 AT ORNEYS Jan. A28, 1969 METHOD AN W. c. TRIPLETT 3,424,242

D APPARATUS FOR DRILLING OFFSHORE WELLS Filed April 15, 1957 sheet 5 of e ATTgRNEYS Jan. 28, 1969 W. c. TRIPLETT 3,424,242

METHOD AND APPARATUS FOR DRILLING OFFSHORE WELLS Filed April 15, 1957 sheet 6 l INVENTOR y W/LL/AM C. TR/PLETT AT ORNEYS United States Patent Oiiice 3,424,242 Patented Jan. 28, 1969 3,424,242 METHOD AND APPARATUS FOR DRILLING OFFSHORE WELLS William C. Triplett, Corpus Christi, Tex., assignor to Chevron Research Company, a corporation of Delaware Continuation-impart of application Ser. No. 625,682, Dec. 3, 1956. This application Apr. 15, 1957, Ser. No. 652,756 U.S. Cl. 166 .6 19 Claims Int. Cl. E21b 43/01, 7/12 ABSTRACT OF THE DISCLOSURE Apparatus and methods of drilling, working in, and completing submerged wells in offshore locations involving the use of conductor means, or casing means extending from a oating vessel to a submerged well head, a releasable coupling for connecting the conductor means or casing means to the well head, guide means for guiding the conductor means or casing means into coupled relation with the well head, and a drilling mechanism guided through the conductor means or casing means to the well site.

Apparatus for drilling and working in a well including movable latches which provide a selectively operable connection between a conductor means or casing means and a submerged Well head.

Apparatus for completing a well including means for guiding a tubular conduit into the casing of a ysubmerged well and seal-ing the thus guided conduit to the casing.

Related application This application is a continuation-in-part of United States Triplett application Ser. No. 625,682, filed Dec. 3, 1956.

General background, objects and summary of invention This invention relates to a method and apparatus for drilling wells in earth formations located under a body of Water and more particularly for drilling offshore wells from a floating drilling platform.

As the search for offshore petroleum deposits moves progressively into deeper Water, the limitations of fixed offshore drilling platforms become more apparent. Fixed platforms not only are very costly to build, but the engineering ditliculties inherent in these structures increase exponentially as the Water depth increases. A practical limitation is reached in waters well above the depth of those covering some potentially available petroleum deposits. Then, too, the susceptibility to storm damage of fixed drilling platforms located in open waters has been amply demonstrated by the destruction of such rigs by storms in the Gulf of Mexico and elsewhere.

It is desirable that some means `be provided for drilling offshore wells which will not be limited in its application by the depth of the water; that relatively very maneuverable drilling apparatus be provided that can be moved from one well site to another with a minimum of delay and expense; that equipment be provided to control the opening of the well bore where it emerges from the submarine earth formations so that control of the Well will not be subject to the hazard of damage through natural or other forces occurring in the water at the well site; that the well control equipment be operated by remote control from the surface of the water to obviate the necessity of using divers to manipulate the equipment; that provision be made for detaching the drilling apparatus from the well control equipment to permit it to proceed to a new location while leaving the Well controlled by the submerged equipment; that provision be made for relocating a submerged drilled well from which the drilling apparatus previously has been disconnected and for reconnecting the drilling apparatus to the well -be manipulation from the surface of the water; that provision be made to enable the drilling apparatus to avoid damage from heavy seas and storms; and that provision be made for controlling at the surface of the water the production from a completed well by remote operation of the submerged Wellhead equipment.

It is among the objects of this invention to provide a novel method and means for satisfying the abovementioned desirable conditions. Other objects Will become apparent as the description of the invention proceeds in conjunction with the accompanying drawings which form part of this specification.

In pursurance of this invention a floating drilling Vessel is anchored over a submerged well site, and wellhead control equipment separate from the vessel is submerged in and at the bottom of the Water and affixed to the bottom at the well site. The fixed wellhead equipment is connected to the floating drilling vessel by a string of flexible conductor casing which serves as a communicating conduit between the drilling vessel and the well. The flexible conductor casing string is arranged to permit the drilling vessel to move with the surface forces on the water without placing undue strain on or causing damage to the xed wellhead control equipment. The wellhead control is operated from the floating drilling vessel remotely and indenpendently of the vessels connection through the flexible conductor casing string, and is not exposed t0 the hazard of malfunctioning which could follow from damage to the ilexible conductor casing. Means are provided for remotely detaching and reattaching the exible conductor casing string to the submerged wellhead, so that the vessel may leave the drilling site or return to it and tbe reconnected with the well through the operation of the apparatus aboard the vessel.

Drawings of preferred embodiments In the drawings:

FIGURE 1 illustrates diagrammatically in elevation and partly in section an example of apparatus employed in the method of this invention.

FIGURE 2 illustrates in sectional elevation details of parts of the apparatus illustrated in FIGURE l.

FIGURE 3 is a plan view of a portion of the apparatus taken along the line 3 3 of FIGURE 2.

FIGURE 4 is an elevational view of a portion of the apparatus taken along the line 4 4 of FIGURE 3.

FIGURE 5 illustrates diagrammatically the arrangement of portions of the apparatus when the drilling vessel is being reconnected to a well.

FIGURE 6 illustrates in sectional elevation details of the apparatus shown in FIGURE 5.

FIGURE 7 is a plan View of a detail of the apparatus taken along the line 7 7 of FIGURE 6.

FIGURE 8 illustrates diagramatically in elevation and partly in section a modication of apparatus employed in the method of this invention.

FIGURE 9 illustrates in elevation and partly in section details of a portion of the apparatus illustrated in FIG- URE 8.

FIGURE 10 is a plan view partly in section of the apparatus taken along the line 10 10 of FIGURE 9.

FIGURE ll is a diagrammatic illustration in elevation and partly in section of details of a modification of a portion of the apparatus.

FIGURE 12 is a schematic illustration of an alternate method for reconnecting the drilling vessel to the submerged wellhead.

Referring to the embodiment of the invention illustrated in FIGURE 1, there is shown a drilling vessel which has been anchored on the surface of the water over the well site. This vessel may be a floating platform such as a barge which is towed to the well site, but preferably as illustrated it is a self-propelled ship which has been constructed or altered for well drilling purposes. The vessel is anchored by four anchors, two at the bow and two at the stern, and each pair of anchors is displaced at an angle of 45 to the longitudinal axis of the ship and hence at 90 to each other to increase the stability of the vessel in its anchored position. The Winches 12 of the bow anchors are manually controlled in the usual manner. However, the stern anchor cables are wound on a winch 14 to be effective as a continuous line so that as the winch rotates one cable will be taken up as the other is paid out. The operation of the winch is governed automatically by a gyroscopically controlled selsyn arrangement which is designed to hold the vessel within 13 of arc of rotation in a horizontal -plane to the position where it originally has been anchored.

The vessel has a bulkhead 16 built transversely across the forward portion of its hull and extending upwardly from the keel a distance appreciably above the water line, The bottom portion of the hull forwardly of the bulkhead has an opening 18 formed in it to provide access to the subjacent body of water from the interior of the vessel. A platform 20 is erected above the opening and above the surface of the water within the hull, and on this platform is positioned a rotary table 22. The platform 20 together with the rotary table and any other equipment which may be on the platform is removable so that access may be had to the opening in the bottom of the hull and equipment and apparatus may be passed through this opening and into the water for a purpose to be described hereinafter.

There is erected on the deck of the vessel for operation in vertical alignment with the opening in the hull a derck 24 by which equipment can be raised and lowered through the opening and through the water. The derrick is fitted with gear and tackle connected to

suitable powerdriven drums

26 and 28 through which the hoisting operations can be accomplished. The vessel also is equipped with the power sources, pumps, tanks and other equipment normally used in a well drilling operation, as well as special equipment used in this invention, and to be described hereinafter.

When the vessel is anchored in position, wellhead control apparatus, designated generally by the number 30, is assembled and supported in the water by

cylindrical pontoons

32 and 34. This apparatus comprises a base 36 which may be, by way of example, made of concrete. The base is illustrated as circular in shape, although it will be apparent that this particular shape is not necessary for its function. One end of a length of rigid conductor casing 38 is secured integrally in the base so that the casing exv tends axially from the bottom of it. The conductor casing extends also above the base a distance suicient to permit the secure connection of equipment to it.

Attached to the top of the conductor casing is an element 40 which has a portion 42 of its exterior surface formed with a conical configuration. An axial conduit 44 is formed through the central portion of the element, in alignment and communicating with the interior of the conductor casing. Included in the conduit is a conically shaped chamber 46, the smallest diameter of which is comparable to the internal diameter of the conductor casing. Coarse screw threads 48 are formed in the upper cylindrical surface of the conduit 44 to receive complementary screw threads 50 formed on an exterior surface of a nipple 52. The upper end of element 40 terminates in a flange 54, and the nipple 52 has a complementary tiange 56 which mates with it. A gasket 58 may lbe placed between the lianges to form a fluid-tight connection. The nipple has an axial opening 60 through it of the same internal dimension as and in alignment with the interior of the conductor casing. Aiixed to the top of and in axial alignment with the nipple is a hydraulically actuated blowout preventer 62 to which exible

hydraulic lines

64 and 66 are attached. The hydraulic lines are wound on a drum 68 mounted on the vessel, and suitable valves are placed in the lines so that the blowout preventer may be remotely operated from aboard the vessel.

A second nipple 70 is affixed to the top portion of the blowout prevented and projects in axial alignment upwardly therefrom. This nipple is designed to recelve an end of a string of exible conductor casing 72 which has an internal diameter comparable to that of the rigid conductor casing 38. The flexible conductor casing is preferably made of a rubber-like material reenforced with steel wires so that it will have high tensile strength, and it may be fastened to the nipple 70 in any manner which will make a secure connection. As illustrated in FIGURE 2, a split clamp 74 is used for this purpose. The flexible conductor casing may be made in sections for convenience 1n handling and the sections joined together by flanges 76 as illustrated in FIGURE l.

Thus, as a consequence of the structure, and as is shown in FIGURE 2, releasable coupling means or connecting means 48 is axially immobilized with respect to the lower portion of the casing means or conductor means. This conductor means or casing means comprises

units

70, 72, 62 and 52` This lower portion of this casing means or conductor means is axially immobilized with respect to anchor means or base 36 by releasable coupling means 48, operable to be released by rotary table 22. With the

lparts

70, 72, 62, S2, 40 and 38 thus interconnected, a continuous conduit wall structure extends from vessel 10 into the well bore. This continuous conduit wall structure provides equipment guiding means for guiding equipment, such as drilling apparatus, between the vessel 10 and a well. The cross section and structure of this wall structure may vary, depending on the part involved. The flexible nature of unit 72 provides a degree of movement in the conductor means to accommodate motion of vessel 10 relative to anchor 36.

As illustrated in FIGURES 2, 3 and 4, the

cylindrical pontoons

32 and 34 are connected to the base 36 by means of four chains, two from each pontoon. The chains have a fixed attachment to the pontoons but are detachably connected to the Ibase by a remotely controlled connection, so that the pontoons may be recovered at the surface of the water when the base is landed on the well site. As shown in FIGURE 3, the free end of each chain terminates in an eye which is received within a clevis which is rigidly attached to the base; the clevis 78 receives the eye 80 of the respective chain 82, and the clevis 84 receives the eye 86 of the chain 88. A pin 90 is inserted through the clevis and eye combination 78-80, and a pin 92 through the clevis and eye combination 84-86. Each pin is attached to a frame 94 in a unitary manner so that when the frame is displaced longitudinally each pin also will be displaced the same distance simultaneously. A line 96 is attached to each frame and runs through a corresponding sheave 98 mounted on the base 36. The lines from each of the two frames are run through their respective sheaves and thence are joined together and connected to a single line 100. The sheaves are mounted at an angle on the ibase to accommodate the angle made by the line 96 and are positioned so that the stress in the line will be in axial alignment with the frame 94.

Line 100 is run through a set of sheaves 102 affixed to the side of pontoon 32 so that the line will clear the pontoon and not become entangled in the wellhead apparatus. The line continues upwardly through the water to aboard the drilling vessel from which it can be manipulated to draw the pins and 92 from the eye and clevis attachments on the base to thereby release the pontoons so that they may be buoyed to the surface and recovered.

The frame 94 and its attached pins are held in place in the eye and clevis connections by a shear pin 104 which is passed transversely through the pin 90 as shown in FIG- URE 3. The shear pins are proportioned to shear under a predetermined stress placed on the lines 96 and prevent the pins 90 and 92 from being accidentally withdrawn from the eye and clevis connections prior to the time it is desired to release the pontoons from the base.

The line 100 is connected to the lines 96 by a shear pin connection 106 incorporating a shear pin 108. This latter shear pin is, of course, proportioned to shear under a greater stress than is required to shear the pins 104 together. Hence, after the pontoons are released from the base additional stress may be placed on the line 100 to release the connection 106, permitting the line to be cleared from the wellhead assembly and recovered aboard the drilling Vessel.

The cylindrical pontoons are connected together by rigid members 110 placed between the corresponding axial ends thereof, These rigid members hold the pontoons in spaced relationship so that they will not impinge upon and damage the flexible conductor easing 72 or other apparatus associated with the wellhead. The members may be and preferably are manifold conduits by which the pontoons are joined to receive simultaneously air or water introduced into them through the

flexible hoses

112 and 114 which are connected to appropriate sources of air and water aboard the drilling vessel. Obviously the buoyancy of the pontoons may be controlled from aboard the drilling vessel by manipulating appropriate valves to inject the proper amount of air or water into the pontoon structures.

The wellhead equipment extending above the base 36 is braced by diagonal bracing members 116. These members are attached to the blowout preventer by a relatively rigid connection and extend thence diagonally outwardly to contact the base near its periphery. The ends of the diagonal members adjacent the base terminate in a foot 118 which is bent into a plane parallel with the top surface of the base. The foot has a circular opening 120 in it which is slotted 122 at one side so that the opening may receive the shank 124 of a headed pin 126 in a sliding connection. The head of the pin engages the topmost surface of the foot to prevent an axial displacement of the foot from the pin connection. However, the foot may be slid out of connection with the pin when the blowout preventer is rotated about its longitudinal axis, carrying the diagonal braces 116 with it.

A valve controlled side take olf conduit is provided in the wellhead equipment so that the liow of fluids from a completed well may be controlled and taken from the well directly at the wellhead where it emerges from the submarine earth formations. As illustrated, a conduit 128 is inserted through a side wall of the rigid conductor casing 38 in a fluid-tight fitting and extends radially therefrom. A remotely operable valve 130 is connected to the conduit in line with a second conduit 132 to which a pipe line 134 is connected. The conduits 128 and 132 may be cast into the concrete base 36 and the valve inserted in a recess formed in the base and covered with a water-tight cover 136.

Control lines

138 and 140 for the valve are passed through the cover through water-tight connections so that the valve and conduits will be protected from damage and from corrosion.

The pipe line 134 preferably is a flexible line such as a steel-reenforced rubber hose which can be brought to the surface so that its upper end may be secured to a buoy 142 until such time as the well is to be placed in production. At this time the pipe line will be connected to suitable separators and tanks on a floating vessel or will be extended by flexible or rigid line to reach along the bottom of the water to shore installations.

As stated previously, after the well site has been selected and the drilling vessel anchored in place the wellhead control apparatus is assembled on its base and supported by pontoons at the surface of the water. The ends 0f the control lines are attached to their respective apparatus in the wellhead assembly, and the end of the flexible conductor casing 72 is secured to the top of the blowout preventer. The control lines are reeled on appropriate drums aboard the vessel so that they can be paid out as the wellhead assembly is submerged. For example, the air and water lines from the pontoons are reeled around the drum 144 which has incorporated with it rotary connections which permit the lines to be continuously connected to appropriate sources of pressurized air and water aboard the vessel.

The surface end of the flexible conductor casing is passed upwardly through the opening 18 in the bottom of the hull of the vessel and through an opening in the platform 20 so that it may be supported by the derrick.

The wellhead assembly is now ready to be lowered to the bottom of the water and fixed there at the drilling site, This is accomplished by injecting water into the pontoons until their 'buoyancy decreases suiciently to permit the wellhead assembly to sink slowly through the water. As the submerged depth of the wellhead assembly increases, sections of flexible conductor casing are added to the conductor casing string so that the upper end of it remains above the water. The upper end of the iiexible conductor casing string may be held on the platform 20 by slips while a section is being added to it.

Buoyant elements 146 are alixed to the flexible conductor casing string at spaced-apart intervals as it is being lowered into the water. These buoyant elements are proportioned to give the flexible conductor casing string substantially neutral buoyancy in the water. Preferably the buoyant elements are made of a water-impervious, rela tively rigid cellular material such as a plastic foam. The presently available commercial material called Styrofoam is suitable for this purpose. The buoyant elements may be attached to the flexible conductor casing string within the hull of the vessel as the sections are made up, and of course if they are attached to the string above the platform 20 the platform will subsequently be removed to permit the flexible conductor casing string together with the attached buoyant element to pass downwardly through the opening 18 in the bottom of the hull.

The hydraulic control lines for the blowout preventer 62 are paid out from reel `68 and secured along the side of the flexible conductor 4casing string as it is made up and lowered into the water. The release line for the pontoons is also brought aboard the vessel and reeled on an appropriate drum, not shown.

As the wellhead assembly approaches the bottom of the water, the length of rigid conductor casing 38 projecting from the bottom of it comes in contact with the submerged earth formations. In muddy and silty bottoms the weight of the apparatus can be used to cause the rigid conductor casing to penetrate some distance into the bottom. However, in order to insure a lirm connection with the earth formation it is preferable to make the rigid conductor casing string of such length that it will penetrate through the silt and into contact with the firmer subterranean formations. When downward progress of the wellhead assembly is stopped by the contact of the lower end of the rigid conductor casing string with the firmer earth formations, a string of tubing to the lower end of which jetting nozzles are attached is inserted into the upper end of the flexible conductor casing string and projected downwardly through the wellhead control equipment and the rigid conductor casing string until the nozzles are proximate the earth'formations. A jetting fluid under pressure is forced down the tubing to jet the rigid conductor casing string into the earth formations. .letting will continue until the base 36 is seated on the earth formations at the bottom of the water. Where the bottom is relatively firm, the engagement of the base with the bottom will stop the further downward travel of the wellhead assembly. However, if the bottom is mushy, the wellhead assembly is held in this desired position by the action of the pontoons with the assistance of the derrick supporting the upper end of the exible conductor casing string. It is desired to keep the wellhead assembly directly on the bottom and positioned so that the upper end of the rigid conductor casing string will not extend above the earth formations and be exposed in the water, nor will the wellhead assembly be sunk into and be covered by silt or mud.

When the base has been landed, the jetting tubing is removed from the casing string and cement tubing and packers inserted therein. Cement is forced down the cement tubing in a manner analagous to the usual practice to cement the rigid conductor casing string to the submerged earth formations. This will assist in holding the wellhead assembly in position, as well as prevent the topmost layers of earth from caving into the hole.

When the rigid conductor casing string has been cemented and the cement tubing withdrawn from the casing, a selfcontained drilling mechanism 148, such as a muddriven turbo drill or an electric drill, is inserted into the exible conductor casing string, through the wellhead equipment and the rigid conductor casing string and into contact with the subteranean formations. The upper open end of the flexible conductor casing is closed by a head member 150, which is securely attached to the casing, through which the operating lines to the drilling mechanism will pass slidably in a fluid-tight connection. The drilling mechanism is supported in the derrick by a wire line 152 which is connected to the drum 26, This drum is automaticaly controlled to take up or let oft line to hold constant Weight on the bit while compensating for vertical motion of the drilling vessel and for increasing depth of the bit as it drills into the subterranean formations.

When a mud-driven turbo drill is used, mud under pressure is fed to the drilling mechanism through a exible hose '154 which also passes through the head member 150 in a slidable fluid-tight connection. In the modification of the invention shown in FGURE 1 the hose 154 is run over a pulley 156 attached to the derrick structure in a position above the end of the flexible conductor casing string. The free end of the hose is connected to a mud pump 158 which will draw drilling mud from the mud tank 160 and force it down the hose to drive the drill turbine.

The mud hose may be made in sections which are added to the string as the drill progresses deeper into the earth.

As illustrated, the sections 162 may be stored aboard in a L hold of the vessel from which they are lifted out by a crane 164 to be added to the mud hose string as needed. A power-driven winch 166 mounted on the deck is detachably secured by cables 168 to the mud hose before it passes over the pulley 156 so that the free end of the mud hose may be drawn up slack and disconnected from the mud pump when a section is to be added to the string. The winch 166 may also be used to place enough tension on the mud hose string to prevent an excess amount of it from following the drilling mechanism into the hole.

The head member 150 has a connection for a mud line 170 through which the mud circulated upwardly from the drilling mechanism will pass from the exible conductor casing to a shale shaker and screen 172 and thence into the mud tank. The return mud may, of course, be treated, inspected and analyzed in conformance with the usual field practice. It will be appreciated that if an electric drill is used the drilling mechanism will be supported in the derrick by a constant feed apparatus in a manner analagous to that explained above, and lche electrical conductors will be passed through the head members 150 through slidable fluid-tight connections. Mud will be circulated down to the drill and back through the exible conductor casing and thence to the mud treating apparatus.

The upper end of the flexible conductor casing string may be supported on the platform 20'. The flexibility and buoyancy of the string will permit some motion of the vessel relative to the fixed wellhead equipment without placing undue strain on the parts. Alternatively the casing fil) lil)

may be supported in the derrick by lines attached to the drum 28 which is automatically controlled to let off and take up line in accordance with the vertical motion of the vessel to prevent it from being placed under stress due to the latter cause.

With the drilling apparatus thus in place and connected to the sources of power aboard the vessel, a hole is drilled into the subterranean formations below the end of the rigid conductor casing string 3d of a diameter large enough to receive a string of surface casing 174. The length of the surface casing string will depend on the nature of the earth formations to which it is to be secured, on the depth of the well it is desired to drill, and on the pressures likely to be encountered as drilling progresses. This string will, for example, extend 500 feet into the earth. When the hole has reached the desired depth, the drilling mechanism is withdrawn and a string of surface casing is made up aboard the drilling vessel and lowered through the exible conductor casing string which will guide it through the wellhead control equipment and thence into the rigid conductor casing string 3'8. It will be appreciated that the surface casing string will be made up from sections in the usual manner and will be progressively lowered through the conductor casing. The upper end of the surface casing string is hung by casing hangers in the rigid conductor casing string so that the upper end of it is adjacent the bottom portion of the wellhead control assembly. Cementing tubing is then run to the bottom of the surface casing string, which is cemented to the earth formations in a manner well known in the art. The cement slurry is placed under enough pressure so that it will be forced into the annular space between the surface casing string and the rigid conductor casing string to a point adjacent the bottom of the base 36. The wellhead assembly will thus be rigidly secured to the surface casing string and thus held in place in its position at the bottom of the water.

The pontoons `32 and 34 may now be detached from the base 36 and recovered. This is accomplished by decreasing the buoyancy of the pontoons to place slack in the chains S2 and 88. The pins 90 and 92 are then withdrawn from the clevis and eye combinations so that the pontoons will be released from their attachment. Water may now be displaced from the pontoons by compressed air and the pontoons oated to the surface where they may be recovered and cleared from the apparatus. It will be appreciated that under some conditions the pontoons may be released from the base prior to the time the surface casing is set and cemented in place.

The drilling mechanism is now again lowered through th the flexible conductor casing string and guided through the wellhead control equipment and the string of surface casing and into contact with the subterranean formation. It is then placed into operation to drill the well. The blowout preventer 62 will assist in maintaining control of the well should conditions require it. As noted previously, the blowout preventer is connected Iby lines 64 and 66 to appropriate valves aboard the vessel by which its action may be controlled. The blowout preventer is preferably of the well-known type which will close around the drill tubing and seal the opening of the well. When a flexible steel-reenforced rubber hose is used for drill tubing, it may be `desirable to embed spaced-apart sections of a rigid conduit in the inner wall of the flexible tubing so that the yblowout preventer may close on the tubing without crushing it. Additionally a complete shutoff blowout preventer may be connected in axial alignment with the blowout preventer 62 to `completely close the opening of the well when the drill tubing is withdrawn from the apparatus.

The well is drilled to the desired depth and completed in accordance with the usual practice. The opening of the well may now be closed by lowering a mass of cement slurry 176 on a wire line .178 to rest in the conical chamber 46 of element 40. The cement slurry may be contained in a plastic sack 180, FIGURE 6, inside 0f a flexible metal petal basket 1482 formed of interleaved spring metal segments, a device known to the art. The basket will be collapsed about the sack of cement slurry as it is lowered through the flexible conductor casing string and the blowout preventer, and the petals will be expanded when the basket is located in the conical cham-ber 46 to confine the mass of slurry in this position. The cement slurry will be placed under sufficient pressure to cause it to conform to the shape of the chamber so that when it is set a lluidgtight seal is made.

With the well thus sealed the exible conductor casing string and the attached blowout preventer may be dis* connected from the wellhead control assembly. This is accomplished by placing the upper end of the llexible conductor casing string in the rotary table 22 and rotating it to unscrew the connection 48-50 at the top of the element 40. All of the principal equipment except the element 40 and the base 36 and the connections between them may now be recovered. The control lines 138 and 140 remain attached to the side take olf valve 130 sothat this valve can be actuated to control the flow of well fluids throuh the pipe line 134. IHence the well is completely sealed at the bottom of the water and, except for the control lines, and in some instances the pipe line, no apparatus extends substantially above the bottom to be damaged by water forces or solid objects impinging against them.

When the cement plug was set in the element 40 and the wire line 178 on which it was lowered had attached to it at spaced intervals along its length guide members 184. These lguide members are proportioned with a circumferential portion of slightly less diameter than the internal diameter of the flexible conductor casing and are secured to the wire line so that they will extend radially from it. When the llexible conductor casing string is detached from the wellhead assembly, the wire line 178 with the attached guides remains secured to the cement plug 176, and the casing is slipped Iupwardly over the guides. With the casing removed, the upper end of the wire line is buoyed at the surface of the water so that it might be recovered.

Should it become necessary to gain entrance to the well for cleaning or other purposes, the wire line 178 and the attached guide members 184 serves as a means for guiding the flexible conductor casing string back to the wellhead. For reconnecting purposes a special guide tting 186 is clamped to the lower end of the flexible conductor casing string. This guide fitting has a circumferential skirt portion 188 extending downwardly from it and proportioned to slip over the flange 54 and seat upon the conically shaped outer surface 42 of the element 40. The litting has an inner cylindrical extension 190 upon the outer surface of which screw threads are formed to mate with and Ibe received by the screw threads 48 of the element 40. The wire line and guide members will thus guide the lower end of the flexible conductor casing string to the submerged xed wellhead and with the assistance of the depending skirt portion 188 it will be brought into axial alignment with the element 40. The upper end of the flexible conductor casing string is then rotated to engage the screw threads to connect the lower end of it to the wellhead assembly. When the connection has been made the wire line 178 is severed where it enters the cement plug and the plug is drilled out to open the well so that the appropriate rewor-king equipment can be guided down through the Ireattached flexible conductor casing string and into the well. When the reworking of the well has been completed, the cement plug 176 again is established in the chamber 46 and the exible conductor casing string is removed in the manner explained 'hereinbefore FIGURE 8 illustrates another embodiment of this invention. In this modification, the drilling vessel has an opening 200 placed through the bottom portion of the hull, and aixed to its periphery in a watertight manner is the end of a vertical open cylinder 202. The cylinder is open to the water at the `bottom and extends upwardly into the hull above the water line. A removable platform 204 is placed across the top of the cylinder and above the surface of the water in it. An opening 206 is formed through the deck of the ship in alignment with the cylinder 202, and this opening also is covered with a removable platfor-m 208.

A crane or derrick 210 is mounted on the deck of the vessel in a position to hoist equipment into and out of the water through the aligned openings in the deck and hull of the vessel and is connected to an automatically controlled hoisting apparatus 212 constructed to let off or take up the lifting cables to compensate for the vertical movement of the ship and the increasing depth of the drill bit when a drilling operation is in progress. This vessel contains the usual apparatus normally used in a rotary drilling operation.

The wellhead equipment in this modification of the invention is more clearly depicted in FIGURES 9 and l0. A base 214 is fabricated of lmetal members and is permanently secured upon

cylindrical pontoons

216 and 218. The pontoons are connected together by conduits 220 and are attached to sources of pressurized air and water aboard the drilling vessel `by

flexible hose

222 and 224 so that their buoyancy may be controlled from the vessel. A .string of 1rigid conductor casing 226 is secured to the center of the base in a unitary manner so that its lower end extends below it.

Wellhead control equipment is secured to the top surface of the base and to the upper end of the string of rigid conductor casing. This equipment comprises an element 228 which has a portion 230` of its lower outer surface of conical configuration with the smaller diameter disposed upwardly. A projection 232 extends upwardly from the lower portion, and this also has a generally conical outer configuration with the smaller dia-meter disposed upwardly. There is an axially disposed opening 234 through the element, in alignment with and having an internal diameter comparable to the conductor casing. A portion of the opening is expanded into a conical chamber 236 which also has its smaller diameter disposed upwardly. Axially spaced

circumferential grooves

238 and 240 are formed in the exterior surface of the projection. These grooves are proportioned to engage parts of a clamping device 242 which is used to detachably secure other portions of the apparatus to the wellhead.

The clamp is made with two

stages

244 and 246, one superimposed axially on the other. The clamp body -has an axial opening 248 through it of sufficient internal diameter to receive within it the projection 232. Each stage has four similar power cylinders 250 disposed in a plane and operatively mounted within the body of the clamp to each slidably move a corresponding connecting rod 252 in a direction radial to the longitudinal axis of the opening 248. Each connecting rod is attached to a ram 254, and hence the rams will be moved radially inwardly and outwardly toward and away from the projection 232. The rams are formed as quadrants of a disc in which the which the radially inwardly portion has been removed to form a circular edge 256 of approximately the same diameter as the base of the

grooves

238 and 240. When the rams are brought together their complementary edges will approach each other closely, and their radially inwardly portions will seat within the `grooves and closely approach the base. A ring of packing material 258 of a resilient substance such as rubber is placed on the bottom of the grooves so that the rams will seat in the groove with a fluid-tight connection. Resilient packing material 260 is placed also on the radial edges of the rams and within the body of the rams as at 262, so that when the rams are forced together the packing material will form a Huid-tight seal both between the ram quadrants and between the rams and the adjacent interior surfaces 264 of the body of the clamp. Thus, when the rams are forced inwardly to engage the grooves a fluidtight seal is formed which will prevent fluids from escaping between the projection 232 and the clamp mechanism. The power cylinders of the clamp are manifolded together and connected by

lines

266 and 268 to the drilling vessel so that they may lbe operated simultaneously to attach or detach the clamp and the element 228.

Extending from the bottom of the clamp housing is a depending skirt portion 270 which terminates in a flared portion 272 in the form of an inverted funnel. The skirt has a lower interior circumferential surface 274 of a conical configuration complementary to the conical surface 230 of the element 228. The skirt is constructed to engage with and seat on the conical surface 230 to assist in bracing the clamp structure on the wellhead and in centralizing the clamp in axial alignment with the projection 232. It also positions the clamp so that the appropriate rams 254 are in alignment with the

corresponding grooves

238 and 240 to enable the clamp to be engaged with and disengaged from the element 228.

A blowout preventer 276 is secured to the top portion of the clamp body and in axial alignment with it, and to the top of the blowout preventer is secured the end of a flexible conductor casing string 278. The blowout preventer is connected by

lines

280 and 282 to the drilling vessel for operation therefrom.

A valve-controlled side take off conduit 284 is provided in the wellhead control equipment in communication with the upper portion of the rigid conductor casing string 226. It is connected to a remotely controllable valve 286 which in turn is connected to a conduit 28S to which the pipe line 290 is attached. The

flexible control lines

292 and 294 for operating the valve are reeled around an appropriate drum aboard the drilling vessel, and the end of the flexible pipe line is buoyed to the surface so that subsequently it may be retrieved and connected to separating equipment and tanks aboard a vessel or to a land installation.

The wellhead control equipment is assembled at the surface of the water and floated on its two pontoons to a position above the well site. The various control lines are fastened to the appropriate units of the wellhead equipment, and they are arranged aboard the vessel so that they may -be paid out as the wellhead assembly is lowered through the water. Prior to lowering, the blowout preventer together with the lower end of the flexible conductor casing string is attached to the element 228 through the action of clamp 242. The upper end of the flexible conductor casing string is passed upwardly through the opening 200 in the hull of the vessel and extends upwardly through an opening in the platform 204.

The wellhead control assembly is now lowered through the water by controlling the buoyancy of the pontoons from aboard the vessel through the

lines

222 and 224. As the wellhead assembly sinks, additional sections are added to the flexible conductor casing string 278 so that the upper end of it remains within the hull of the vessel. Buoyant elements 296 are positioned along the length of the flexible conductor casing string as it is made up. These buoyant elements may, as mentioned heretofore, be made of a relatively rigid cellular material, such as plastic foam. The buoyant elements may be substantially toroidal in form and be made in sections to be put together circumferentially around the flexible conductor casing string. They are then secured together and to the casing so that they will remain in place as they become submerged in the water and distribute their buoyant effect along the length of the casing string. In the instant modification of the invention it is preferable that the conductor casing string be given a positive buoyancy for a purpose to be described 'hereinaftetn The control lines to the clamping device 242, and the lines to the blowout preventer, may be secured to the side of the flexible conductor casing string as it is made up, and are wound on

appropriate drums

298 and 300 respectively aboard the vessel. Appropriate valves are placed in the control lines so that the submerged apparatus can be operated from aboard the vessel.

The wellhead control assembly is lowered until the bottom of the rigid conductor casing string contacts firm submarine earth formations, after which the rigid conductor casing string is jetted in until the

pontoons

216 and 218 rest ou the earth formations at the bottom of the water. In silty or muddy bottoms the pontoons may be permitted to sink into the -bottom until the base 214 is substantially even with the surface of the earth formations at the bottom of the water. The penetration of the pontoons into the bottom may, of course, be controlled by regulating their buoyancy.

As the wellhead control assembly is landed, a length of rigid casing 302 is added to the topmost portion of the flexible conductor casing string in a position to extend through the opening in the platform 204 and for some distance above and below the platform as illustrated in FIGURE 8. A gimbal mounting 304 is positioned on the platform and circumferentially surrounding the section of rigid conductor casing. This section of casing ts slidably within the gimbal mounting so that it may move longitudinally relative thereto as the ship is displaced vertically by the action of the water. Roller bearings 306 may be placed in the radially inwardly face of the gimbal mount so that the casing section may slide through it with minimum friction. The positive buoyancy of the flexible conductor casing will assist in retaining the rigid section 302 within the gimbal mounting, and the top of the flexible conductor casing string may be additionally supported from the derrick by an automatically operated device to compensate for vertical movement of the vessel, analagous to that discussed with reference to FIGURE l. A flange 308 is placed on the topmost portion of the rigid section to assist in preventing it from disengaging with the gimbal mount. This arrangement permits the drilling vessel to move with the water with the minimum displacement of the upper end of the flexible lconductor casing string. With the apparatus thus assembled, the rigid conductor casing string is cemented to the earth formations it penetrates.

In this modification of the invention, drilling is accomplished by rotating a string of drill tubing 310 by a rotary table 312 mounted on the platform 208. The string is made up in the derrick from the deck of the vessel in a manner analagous to that commonly used in oil field practice and inserted into the upper end of the flexible conductor casing string, which guides it down to the submerged wellhead control equipment. The drill string is extended downwardly until the bit 314 is in contact with the submerged earth formations. Drilling mud is pumped down the drill tubing from the mud tank 316 through a swivel 318 and returns through the flexible conductor casing string, from which it flows through a connection 320 in the drilling head assembly 322. The mud is reconditioned and returned to the mud tank for recirculation.

A bore hole is drilled below the end of the conductor casing string to accept a predetermined length of surface casing 324 which is inserted into the 'bore hole and cemented in place and to the conductor casing string, in a manner described heretofore, to anchor the wellhead control equipment to the well.

When the well has been drilled to the desired depth, a cement plug is set in the conical chamber 236 of the element 228. The cement plug is let down into the chamber on a wire line which has guide elements for the ilexible conductor casing string attached to it in the manner described heretofore.

When the cement plug is set, the clamp 242 is released from its engagement with the element 228 by remote operation from the floating drilling vessel. The flexible conductor casing string, together with the blowout preventer and clamp attached to the end of it, is withdrawn from the water and onto the drilling vessel. The air and water lines to the pontoons may now be severed at the wellhead and reeled aboard the vessel.

As described heretofore the side take off valve 286 is operated through the

lines

292 and 294 to control the flow of fluids from the producing well. It will be appreciated that when the vessel leaves the drilling site these control lines will be disconnected from the vessel and supported at the surface of the water by a buoy '326 so that they may subsequently be retrieved and connected to a `suitable power source to again control the valve.

When it is desired to reopen the well for reworking or other purposes, the clamp 242 is attached to the lower end of the flexible cond-uctor casing string which is guided down to the wellhead on the wire line attached to the element 228 in the manner described heretofore with relation to FIGURES and 6. As has been noted previously, projection 232 is of a generally conical conguration with the smaller diameter positioned uppermost. Thus as the depending skirt 270 of the clamp body approaches the fixed wellhead equipment it will be guided over the upper end of the projection, assisted by the ared portion 272, and thence proceed downwardly along its conical outer surface, guiding the clamp body into a position surrounding and in axial alignment with the projection. When the interior conical surface 274 of the depending skirt portion -seats on the complementary conical surface 230 of the element 228, the clamp will be positioned so that the rams 254 are in -radial alignment with the

grooves

238 and 240. The clamp is then actuated to close the rams onto the projection 232 to secure the lower end of the flexible conductor casing string to tthe fixed wellhead equipment.

An alternative means for reconnecting the llexible conductor casing to the submerged wellhead apparatus is illustrated in FIGURES 11 and 12. In this modification the mass of cement slurry 176 which is used to occlude the opening of the well at the element 228 has embedded in it a socket 328 of drillatble tubular material such as an appropriate synthetic resin, or soft metal. A centralizer 330 of drillable material is attached to the upper portion of the socket in a position to extend above the mass of cement slurry. The socket and centralizer are incorporated in the assemblage prior to the time the basket of slurry is lowered to the wellhead apparatus. The centralizer element is made with an outside diameter which will permit it to slide through the flexible conductor casing string and associated equipment and fit snugly within the opening 234 of the element 228. It is designed to hold the open end of the socket 328 centralized within and in axial alignment with the opening 234. The upper surfaces of the centralizer element and socket are formed with a conical configuration 331 to assist in guiding apparatus into the socket. When the cement is positioned in the conical chamber 236 and is set, the socket will be fixed rigidly in its axially aligned position.

The wire line 332 by which the basket of cement slurry was lowered into the chamber 236 has guide members 334 secured along its length in a manner similar to that of the guide members 184 described heretofore. However, the guide members 334 have an external diameter which will permit a string of pipe or tubing 336 to be slid over them. The wire line and guides are employed to guide the lower end of the string to the submerged wellhead and into the socket 328. The inside diameter of the socket is large enough to receive freely the end of the string 336.

Flexible packing elements

338 and 340 are aixed to and positioned circumferentially around the end of the string where it engages the inner wall of the socket to act as centralizers to hold the lower end of the string in axial alignment with the opening 234 and thus with the element 228.

The string 336 now forms a means connecting the submerged wellhead equipment and the floating drilling platform and can be used as a guide while lowering the end of the flexible conductor casing and its attached clamp to the submerged wellhead equipment for re-attachment thereto. The string of pipe or tubing provides a more rigid guide means than the wire line 332 and hence will assist in guiding the lower end of the flexible conductor casing and its attached equipment more positively into axial alignment with the submerged element 228, especially when rough water or strong ocean currents are present at the drill site. Obviously guide elements similar to the elements 184 described heretofore may be attached to the string 336 at intervals along its length in a manner similar to that described in relation t0 FIGURES 5 and 6, for guiding the flexible conductor casing string to the submerged wellhead. However, if the apparatus of the present modilication is employed, these guide means may be dispensed with by -using a blowout preventer, such as the blowout preventer 276 described hereinbefore, as part of the assembly attached to the lower end of the llexible conductor casing string when it is lowered for reattachment to the submerged wellhead.

In accordance with this latter procedure the blowout preventer 276 is closed lightly upon the string 336 when the llexible conductor casing is to be lowered for reattachment to the submerged wellhead, in a manner to permit the blowout preventer and the equipment connected to it to slide downwardly along the string without permitting appreciable lateral motion of the parts. Thus the string will guide the clamp 242 to the submerged element 228 and substantially in axial alignment with the latter. The depending skirt portion 270` will perform the function as explained hereinbefore .of centering the clamp over the projection 232 and in radial alignment with the

circumferential grooves

238 and 240, so that the clamp rams can be closed to attach the flexible conductor casing string to the submerged wellhead.

The modification of apparatus exemplified in -FIGURES 1l and l2 lends itself to a further alternative means for reattaching the flexible conductor casing string to the submerged wellhead equipment. In this alternative, the blowout preventer 276 is again included in the apparatus attached to the lower end of the flexible conductor casing string. The blowout preventer is closed tightly upon the string 336 and adjacent its lower end prior to the time the string is lowered along the wire line guide. Enough of the lower end of the string 336 is left projecting below and beyond the clamp body so that the lower end of the string may be received within a socket 328` without interference from the equipment attached above it. The lower end of the flexible conductor casing string, together with its associated equipment, is lowered together with the string 336, and the wire line guide means will direct the end of the string into engagement with the socket. When this engagement has been accomplished, the blowout preventer 276 is opened by remote control from the lloating drilling platform a suliicient amount to permit the lower end of the flexible conductor casing string and its associated equipment to slide down the remaining length of the string until the clamp device 248` is positioned to engage and be affixed to the submerged element 228.

As has been explained hereinbefore, after the lower en-d of the flexible conductor casing string has been reattached to the submerged wellhead equipment the wire line, which was used to lower the basket assembly of cement slurry into place to occlude the opening of the well and which subsequently functioned as a guide means for reattaching the flexible conductor casing string to the submerged wellhead equipment, is severed and the cement plug is drilled out to reopen the Well.

It is apparent from the above description of the several exemplary embodiments of the apparatus employed in the method of lthis invention that it achieves the objects set forth at the beginning of the specification. lIt is obvious that other modifications than those illustrated' may be made employing the inventive concept without departing from it; therefore it is desired that this invention not be limited by the specific exemplary embodiments illustrated herein, but that it include all equivalents within the scope of the appended claims.

I claim:

' 1. The method of drilling a well in a submarine location comprising anchoring a floating drilling vessel on the surface of a body of water above a submerged well site, supporting wellhead control equipment on the surface of the water adjacent said vessel by pontoon means of controllable buoyancy, connecting said pontoon means to said vessel by control means to control the buoyancy of said pontoon means from said vessel, connecting one end of a laterally flexible conductor casing separate from said pontoon means to said wellhead control equipment, lowering said wellhead control equipment and the connected said one end of said laterally flexible conductor casing and said pontoon means to the bottom of said body of water by controlling the buoyancy of said pontoon means from said vessel by said control means, afflxing said wellhead control equipment to the earth formations of the underwater bottom to secure said equipment in a submerged position at said underwater bottom, mounting the other end of said laterally flexible conductor casing on said vessel, inserting a drilling mechanism from said vessel longitudinally through said laterally flexible conductor casing and the submerged wellhead control equipment and into contact with the submerged earth formations, operating said drilling mechanism from said vessel and drilling a well bore into said submerged earth formations, and remotely operating said wellhead control equipment from said vessel to control the opening of said well bore at the bottom of said body of water.

2. The method for forming and controlling a well in earth formations submerged under water comprising anchoring a drilling platform on the surface of a body of water above a submerged Well site, assembling at said surface of said water apparatus for controlling the opening of a well bore and including a controlled conduit for conducting well fluids from said well bore, connecting said apparatus to said platform by flexible operating means for remote operation of said apparatus from said platform, connecting one end of flexible conductor casing to said well control apparatus by a detachable connector remotely operated from said platform, lowering said well control apparatus to the bottom of said water to rest on the top of the earth formations submerged under said body of water while retaining the other end of said flexible conductor casing at said surface of said water, afixing said Well control apparatus at said bottom of said water, mounting said other end of said flexible conductor casing on said drilling platform, inserting a drilling mechanism from said drilling platform longitudinally through said flexible conductor casing and said well control apparatus, operating said drilling mechanism from said drilling platform to drill a well bore in the submerged earth formations, withdrawing said drilling mechanism from said well bore said well control apparatus and said flexible conductor casing, closing the opening of said well bore at said well control apparatus by remote operation of said well control apparatus from said platform, detaching said one end of said flexible conductor casing from said well control apparatus at said bottom of said water by operating said detachable connector from said platform and retrieving said flexible conductor casing aboard said platform, and controlling the flow of fluids from said well through said conduit by operating said well control apparatus at said bottom of said water from said platform.

3. The method for establishing a wellhead at a well site submerged under water comprising assembling wellhead control equipment at the surface of a body of water, supporting said control equipment at said surface by pontoons of controllable buoyancy, detachably connecting said control equipment to said pontoons by means operable from said surface of the water to detach the connection, connecting one end of a laterally flexible conductor casing separate from said pontoons to said control equipment, connecting said control equipment to actuating means therefor for remote operation of said control equipment from said surface of the water, connecting said pontoons to buoyancy control means therefor for remote control of the buoyancy of said pontoons from said surface of the water, lowering said control equipment and said pontoons connected thereto to the bottom of said body of water by controlling the buoyancy of said pontoons from said surface of the water while retaining the other end of said laterally flexible conductor casing at said surface of the Water, aflixing said control equipment at said bottom of the water to the submerged earth formations, and detaching said pontoons from said control equipment while retaining said laterally flexible conductor casing connected to said control equipment.

4. Apparatus for drilling and working in a well submerged under a body of water from a platform at the surface of the water comprising a platform at the surface of a body of water above a submerged well site, wellhead equipment submerged in said water at said well site, a casing extending downwardly from said paltform through said water to said wellhead equipment, means on said platform for raising and lowering said casing through said water, a remotely controllable connector for connecting and disconnecting an end of said casing and said wellhead equipment, said connector comprising a housing attached to the lower end of said casing and having an opening therethrough in axial alignment with said casing, latching members slidably mounted in said housing and movable transversely with relation to the axis of said opening to project radially inwardly into said opening and to retract radially outwardly from said opening, operating means to move said latching members in opposed relationship alternatively to approach and recede from each other, a remote control means on said platform for said operating means, an exterior portion of said submerged wellhead equipment constructed to be received within said opening in said housing in axial alignment therewith a circumferential recess in said exterior portion, complementary engaging means on said wellhead equipment and on said connector housing disposed to engage each other in concentric relationship as said casing is lowered from said platform and to position said connector on said wellhead equipment with said latching members in transverse alignment with said circumferential recess to be disposed in said circumferential recess when said latching members approach each other.

5. Apparatus for drilling wells in submarine locations comprising a drilling platform at the surface of a body of water above a submerged well site, a landing base positioned at the bottom of said body of water at said well site and resting on the earth formations at said bottom of said body of water, a casing projecting downwardly from said landing base and ailixed to the said earth formations and said landing base, an element permanently affixed t0 and projecting upwardly from said landing base and terminating closely proximate to said bottom of said body of water, a radially enlarged inner chamber in said element communicating axially with said casing, a remotely operable blowout preventer detachably connected to the upper portion of said element and communicating with said chamber, a flexible conductor casing attached at one end to and communicating with said blowout preventer and supported at the other end by said drilling platform, and means adapted to be lowered from said drilling platform through said flexible conductor casing and said blowout preventer and into said radially enlarged inner chamber and operable to form a fluid-tight closure at said inner chamber.

6. Apparatus for drilling and working in oil wells in submarine locations comprising a floating drilling vessel anchored in the water above a well site, wellhead control equipment submerged in and at the bottom of the water at said well site and attached to the earth formations at said bottom of the water, a flexible conductor casing, blowout preventer means connected to the lower end of said flexible conductor casing, a remotely operable detachable connector for connecting said blowout preventer means to said wellhead control equipment, said flexible conductor casing extending upwardly to said ydrilling vessel, operating means connecting said detachable connector with said drilling vessel and operable at said drilling vessel to detach said blowout preventer means from said wellhead control equipment, buoyant supports for said flexible conductor casing attached to said flexible conductor casing at spaced-apart locations throughout the length thereof and providing substantially neutral buoyancy in the water for said flexible conductor casing, gimbal means on said drilling vessel and supporting the upper end of said flexible conductor casing, a rotary table mounted on said Vessel in substantially vertical alignment with said gimbal means, a ,drilling mechanism adapted to be introduced through said rotary table and said flexible conductor casing and said blowout preventer means and said wellhead control equipment and into contact with the submarine earth formations, and means to operate said drilling mechanism from said vessel to drill a well in said submarine earth formations.

7. Apparatus for drilling and working in a well in earth formations submerged under water comprising a drilling platform anchored in a body of water above a submerged well site, wellhead control equipment submerged in and at the bottom of said body of water and aflxed to the submerged earth formations, a flexible conductor casing extending downwardly from said platform through said body of water, a connector means for detachably connecting one end of said flexible conductor casing to said wellhead control equipment, means on said drilling platform for remotely operating said connector means to connect and disconnect said flexible conductor casing and said wellhead control equipment, a gimbal mount on said platform, means slidably supporting the other end of said flexible conductor casing in said gimbal mount, buoyant members attached in spaced-apart locations along the length of said flexible conductor casing to provide substantially neutral buoyancy for said flexible conductor casing in said body of water, a drilling mechanism inserted axially through said flexible conductor casing and said wellhead control equipment and into contact with said earth formations, means to operate said drilling mechanism from said platform, and means for operating said wellhead control apparatus from said platform.

8. Apparatus for offshore -drilling and working in a well wherein a well bore is drilled into the submerged land of an underwater bottom by apparatus lowered through the water from a drilling platform at the surface of the water comprising a casing extending downwardly from said drilling platform through said water, means on said platform for raising and lowering said casing through said water, well control equipment submerged in said water, a connector for connecting and disconnecting the lower end of said casing and said well control equipment, said connector comprising a housing affixed to said end of said casing in fluid-tight relationship and having an opening there` through in axial alignment with said casing, members mounted in said housing and movable transversely with relationz to the axis of said opening, means remotely operating atthe surface of said water to move said members in opposed relationship alternatively to approach and recede from each other, a surface formed on an exterior portion of said well control equipment and proportioned to be received in said opening of said housing, the radially inwardly portions of said members formed to abut said surface in fluid-tight relationship as said members approach each other, means forming a fluid-tight seal between adjacent said members and between said members and said housing when said members abut said surface thereby to connect said housing to said well control equipment in a fluid-tight relationship, and guide means extending from said well contro-l equipment upwardly to the surface of said water and disposed within said casing to guide said connector into alignment with said surface on the submerged said well control equipment as said casing is lowered from said platform.

9. The method for establishing wellhead control equipment at a well site submerged under water comprising connecting together an assembly of wellhead control equipment at the surface of a body of water, supporting said assembly at said surface by float means of controllable buoyancy, connecting said float means to a control vessel at said surface by means for remote control of the buoyancy of said float means from said vessel, connecting one end of a laterally flexible conductor casing separate from said float means to said assembly, lowering said float means and said assembly to the bottom of said body of water by decreasing the buoyancy of said float means by operation of said means for remote control thereof, con necting the other end of said laterally flexible conductor casing to a drilling vessel at said surface, lowering a holeforming apparatus from said drilling vessel through said laterally flexible conductor casing and said assembly and forming a hole in the submerged earth, lowering a length o`f rigid casing through said laterally flexible conductor casing and said assembly and into said hole and terminating the upper end of said length of rigid casing within a portion of said assembly, lowering a cementing tool from said vessel through said laterally flexible conductor casing and said assembly and into said length of rigid casing and operating said cementing tool to cement said rigid casing to the submerged earth formations and to said portion of said assembly.

10. Apparatus for completing a well drilled into a formation under a body of water comprising a casing in the well, concrete sealing the casing exterior to the formation, a buoyantly supported floating vessel, elongated and laterally flexible anchoring means holding the vessel in tension over the well, a tubular conduit, elongated guide means extending from the bottom of the water body to the surface, means maintaining the lower extremity of the guide means in fixed relation to the casing, means maintaining the upper extremity of the guide means in the region of the vessel, means for lowering the tubular conduit from the vessel in engagement with the guide means whereby the tubular conduit is constrained by the guide means to enter the casing as it is lowered, and means for sealing the conduit and casing in fixed communicating relation below the water surface.

11. Apparatus for completing a well drilled into a formation under a body of water comprising a casing in the well, concrete sealing the casing exterior to the formation, a buoyantly supported floating vessel, elongated and laterally flexible anchoring means holding the vessel in tension over the well, a tubing, elongated guide means extending from the bottom of the water body to the surface, means maintaining the lower extremity of the guide means in fixed relation to the casing, means maintaining the upper extremity of the guide means in the region of the vessel, means for lowering the tubing from the vessel in engagement with the guide means whereby the tubing iS constrained by the guide means to enter the casing as it is lowered, means for sealing the tubing and casing in fixed communicating relation, and a flow conduit extending between the tubing and the water surface.

12. Apparatus for carrying out operations such as drilling and working in a Well in a formation underlying a body of water comprising:

a floating vessel;

a generally upright elongated hollow conductor means disposed beneath the vessel so that the upper end of the conductor means terminates in the vicinity of the vessel;

an anchor including an opening therethrough communicating at one end with the upper end of the well;

releasable coupling means for connecting the lower end of the conductor means to the anchor to form through the opening in the anchor a continuous conduit wall structure between the well and the vessel;

means for releasing the coupling means from the Water surface to per-mit the conductor means and anchor to be separated from each other; and

means for guiding the conductor means from the floating vessel to the anchor so the coupling means connects to the anchor to form the said continuous conduit wall structure;

said continuous conduit wall structure defining equipment guiding means.

13. Apparatus for carrying out operations such as drilling and working in a well in a formation underlying a body of water comprising:

a lloating vessel;

a rotary drilling rig including a rotary table mounted on the vessel;

a generally upright elongated hollow conductor means disposed beneath the vessel so the upper end of the conductor means terminates at the Vessel below the rotary table to leave a free space between the table and the upper end of the conductor means;

means for moving the conductor means down and up to bring the conductor means lower end into and out of a coupling position with the anchor;

remotely actuatable coupling means for connecting the lower end of the conductor means, when in the coupling position, to the anchor to form through the opening in the anchor a continuous conduit wall structure between the well and the vessel;

a lateraly flexible elongated guide member;

means connecting the guide member lower end to the formation adjacent the well, said guide member extending upwardly to the vessel;

means engaging the conductor means and guide member so that as the conductor means is lowered it is constrained by the guide member to cause the conductor means, coupling means, and anchor to be in the coupling position; and

remote control -means for actuating the coupling means from the water surface to permit the conductor means and anchor to be connected to and separated from each other;

said continuous conduit wall structure defining equipment guiding means.

.14. Apparatus to facilitate operations such as drilling and working in a well in a formation underlying a body of water comprising:

a floating vessel;

generally upright elongated hollow condutor means disposed beneath the vessel sothe upper end of the conductor means terminates at the lvessel;

anchor means secured to the formation and having an opening communicating with the upper end of the Well;

releasable coupling means for sealing the lower end of the conductor means to said anchor means to form a continuous conduit wall structure between the well and the vessel;

an elongated guide member extending down from the vessel through the conductor means and into the opening in said anchor means;

means for supporting the guide member in a generally upright position;

means for lowering or raising the conductor means with respect to the anchor means to move it into or out of sealing position with the anchor means while the guide member is disposed in the anchor means to constrain and guide the conductor means; and

remote control means external of the conductor means for releasing the coupling means from the water surface to permit the conductor means and anchor means to be separated from each other so the conductor means can be raised from the anchor means while the guide member is in the anchor means.

1-5. Apparatus for carrying out operations such as drilling and working in a well in a formation underlying a body of water comprising:

a floating vessel; generally upright elongated hollow conductor means disposed beneath the vessel so that the upper end of the conductor means terminates in the vicinity of the vessel; an anchor including an opening therethrough communicating at one end with the upper end of the well; releasable coupling means for connecting a lower portion of the conductor means to the anchor to form through the opening in the anchor a continuous conduit wall structure between the well and the vessel;

said releasable coupling means being axially immobilized with respect to said lower portion of said conductor means,

means for releasing the coupling means from the water surface to permit the conductor means and anchor to be separated from each other; and -means for guiding the conductor means from the floating vessel to the anchor so the coupling means connects to the anchor to form said continuous conduit Wall structure, with said releasable coupling means being axially immobilized with respect to said lower portion of said conductor means and said lower portion of said conductor means being axially immobilized with respect to said anchor;

said continuous conduit -wall structure defining drilling equipment guiding means.

16. Apparatus to facilitate operations such as drilling and working in a well in a formation underlying a body of water comprising:

a floating vessel;

generally upright elongated hollow conductor means disposed beneath the vessel so the upper end of the conductor means terminates at the vessel;

anchor means secured to the lformation and having an opening communicating with the upper end of the well;

releasable coupling means for connecting a lower portion of the conductor means to said anchor means to form a continuous conduit wall structure between the well and the vessel;

an elongated guide member extending down from the vessel and into connected relation with said anchor means;

means for supporting the guide member in a generally upright position;

means for lowering or raising the conductor means with respect to the anchor means to move it into or out of connecting position with the anchor means while the guide member is connected with the anchor means, with said guide member operating, during lowering of said conductor means, to constrain and guide the conductor means from said floating vessel to said anchor means; and

remote control means for releasing the coupling means from the water surface to permit the conductor means and anchor means to be separated from each other so the conductor means can be raised from the anchor means while the guide member is connected with the anchor means;

said releasable coupling means being axially immo- Abilized with respect to said lower portion of said conductor means.

17. Apparatus to facilitate operations such as drilling and working in a well in a formation underlying a body of water comprising:

a floating vessel;

means for supporting the guide member in a generally upright position;

remote control means for releasing the coupling means from the water surface to permit the conductor means and anchor means to be separated from each other so the conductor means can raised from the anchor means while the guide member is connected with the anchor means;

said releasable coupling means -being axially immobilized with respect to said lower portion of said conductor means; and

said continuous conduit wall structure defining drilling equipment guiding means.

18. Apparatus for drilling and working in a well submerged under a body of water from a platform at the surface of the water comprising:

a platform at the -surface of a body of water above a submerged well site,

well head equipment submerged in said water at Said well site,

casing means extending downwardly from said platform through -said water to said well head equipment,

means on said platform for raising and lowering said casing means through said water,

a remotely controllable connector for connecting and disconnecting a lower portion of said casing means and said well head equipment,

said remotely controllable connector including rst coupling means including a body means having an opening therethrough in axial alignment with said casing means,

latching members movably mounted on said body means and movable, at least in part, transversely with relation to the axis of said opening,

operating mean-s operable to move said latching members in generally opposed relationship alternatively to generally recede from and approach each other,

a remote control means on said platform for said operating means,

second coupling means connectable with said first coupling means when disposed in generally axial alignment with said first coupling means,

recess means on said second coupling means extending generally transversely of said axis of said opening .and operable to Ireceive said latching members,

first and second complementary engaging means carried respectively by said submerged well head equipment and said casing means, said first and second complementary engaging means being engageable with each other in generally concentric relationship in response to lowering of said casing means from said platform and positioning said first coupling means with said latchng members in generally transverse alignment with said recess means,

22 one of said rst and second coupling means being attached to said lower portion of said casing means, and the other of said first and second coupling means being attached to said submerged well head equipment. 19. The method for forming and controlling a well in earth formations submerged under water comprising:

anchoring a drilling platform on the surface of a body of water above a submerged Well site;

assembling at said surface of said water control apparatus for controlling the opening of a well lbore and including a controlled conduit for conducting well uids from said well bore;

connecting said apparatus to said platform by ilexible operating means for remote operation of said apparatus from said platform;

releasably connecting the lower end of conductor means to said apparatus to axially immobilize said lower end of said conductor means in fixed relation relative to said apparatus and in communication with said controlled circuit, with the connection between said conductor means and said apparatus being selectively releasable from said platform;

mechanically and releasably maintaining said connection between said conductor means and said apparatus;

lowering said well control apparatus to the bottom of said water to rest on the top of the earth formations submerged under said body of water while retaining the other end of said conductor means at said surface of said water;

aflixing said well control apparatus at said bottom of said water;

mounting said other end of said conductor means on said drilling platform;

inserting a drilling mechanism from said drilling platform longitudinally through said conductor means and said well control apparatus;

operating said drilling mechanism from said drilling platform to drill a well bore in the submerged formations;

Withdrawing said drilling mechanism from said well bore, said ywell control apparatus and said conductor means;

closing the opening of said well bore at said well control lapparatus by remote operation of said Well control apparatus from said platform;

detaching said one end of said conductor means from said well control apparatus at said bottom of said water by operating said selectively releasable connection from said platform and retrieving said conductor means aboard said platform;

and controlling the flow of fluids from said well through said conduit by operating said control apparatus at said Ibottom of said water from said platform.

References Cited UNITED STATES PATENTS Re.24,083 1l/l955 McNeill 175--7 1,766,628 6/1930 Grant 175-7 1,960,261 5/1934 `Centeno 166-72 2,187,871 l/l940 Voorhees 175--7 2,873,027 2/1957 Gilbert 175-7 2,808,230 10/1957 McNeill et al 175-7 962,019 6/1910 Flood et al. 175-7 1,764,488 6/1930 Zublin l66-241 2,476,309 7/1949 Lang 175-7 2,512,783 6/1950 Tucker 175--7 2,610,028 9/ 1952 Smith 166-224 2,684,575 7/1954 *Pryor et al. 175-7 2,854,215 9/1958V Cox et al. 175-7 2,676,787 4/1954 Johnson 175-7 CHARLES E. OCONNELL, Primary Examiner.

RICHARD E. FAVOREAU, Assistant Examiner.