US3414067A

US3414067A - Drilling

Info

Publication number: US3414067A
Application number: US649137A
Authority: US
Inventors: Robert F Bauer; Stratton Hal; Aaron D Rhodes
Original assignee: Shell Oil Co
Current assignee: Shell USA Inc
Priority date: 1957-03-28
Filing date: 1957-03-28
Publication date: 1968-12-03
Anticipated expiration: 1985-12-03
Also published as: GB873480A

Description

Dec. 3, 1968 BAUER ET AL DRILLING Filed March 28, 1957 7 Sheets-Sheet 1 INVENTOR'S'. ROBERT E BAUER HAL STRATTON AARON D. RHODES V. AIZORNEYS Dec. 3, 1968 v BAUER ET AL 3,414,067

DRILLING Filed March 28, 1957 7 Sheets-Sheet 2 INVENTORS ROBERT E BAUER HAL .STRATTON BY AARON D. RHODES ATTORNEYS FIG. 2.

DRILLING 7 Sheets-Sheet 5 Filed March 28, 1957 Dec. 3, 1968 R. F. BAUER ET AL 3,414,067

DRILLING Filed March 28, 1957 7 Sheets-Sheet 1 r0 VESSEL INVENTOR-Sf 45 ROBERT F BAUER HAL STRATTON BY AARON 0. R/-/00Es A TTORNEYS Dec. 3, 1968 BAUER ET AL 3,414,067

DRILLING v 7 Filed March 28, 1957 7 Sheets-Sheet 5 INVENTORS ROBERT/T BAUER HAL STRATTON BY AARON D. RHODES Dec. 3, 1968 BAUER ET AL DRILLING 7 Sheets-Sheet 6 Filed March 28. 1957 FIG 6.

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United States Patent 3,414,067 DRILLING Robert F. Bauer, Whittier, Hal Stratton, Pasadena, and

Aaron D. Rhodes, Arcadia, Calif, assiguors, by direct and mesne assignments, to Shell Oil Company, Los

Angeles, Calif., a corporation of Delaware Filed Mar. 28, 1957, Ser. No. 649,137 21 Claims. (CI. 175-7) This invention relates to apparatus for drilling and working on underwater wells.

The apparatus of the invention may be used in connection with wells under any kind of water, whether marine or fresh, but for simplification of explanation of the invention, the apparatus is described as being used in an ocean.

At the present time, there is considerable activity in exploring and drilling for oil and gas at offshore locations. Currently, most of the drilling is done from stationary structures rigidly anchored to the underwater formation. These structures provide static bases for the drilling equipment and are satisfactory for relatively shallow water. However, for deeper water, say depths of several hundred feet, stationary structures are not always economically practical. Furthermore, the stationary structures are permanent installations which may be navigation hazards.

Recently there has been developed, as described in copending application Ser. No. 468,214, filed Nov. 12, 1954, now Patent No. 2,808,229, apparatus and method for drilling underwater wells from a floating vessel. Drilling from a floating vessel has the advantage over drilling from a stationary structure that the floating vessel may be readily moved from one location to another, is less expensive to set up, and may be quickly removed in the event of a storm.

One of the difiiculties in drilling or working on an underwater well from a floating vessel is in guiding drilling and other equipment such .as tubing, casing, etc., to the well from the surface of the water. The movement of a floating vessel due to wind, current and wave action, which is almost invariably present, makes it difficult to relocate the well once equipment is moved from it.

This invention provides drilling apparatus in which equipment may readily be guided from a floating vessel to and from an underwater well.

Briefly, the invention contemplates apparatus for drilling a hole in a formation underlying a body of water. The apparatus includes a floating vessel and means for anchoring the vessel over the hole or well site. A well head base adapted to be secured firmly to the formation is anchored at the well site. The base includes a receiver which overlies the upper end of the hole. An elongated conductor is adapted to fit around .a drill string which is adapted to extend from the vessel into the hole. The conductor is adapted at its lower end to seal to the receiver, and extend from the receiver to the floating vessel to provide a closed passageway around the drill string from the receiver to the vessel. Means are provided for lowering and guiding the conductor so that as it is lowered, the lower end of the conductor fits into sealing relationship with the receiver and registers with the upper end of the hole.

In the preferred form, the elongated conductor is provided with buoyant support to maintain it in a substantially upright position, and in relatively shallow water the conductor also preferably includes a section of flexible hose in its lower portion to accommodate lateral displacement of the conductor. Also in the preferred form, the conductor is adapted to make a quick seal to and release from the receiver by means which are controlled remotely from the floating vessel, so that the conductor may be either quickly sealed to or released from the receiver by remote control.

Also in the preferred embodiment, the receiver includes a blow-out preventer which can be controlled from the surface of the water to close the upper end of thewell. Thus, the well can be safely shut in while drilling operations are temporarily suspended, the top of the conductor then lowered a substantial distance below the water surface and no structure is left at or near the surface of the water which would either be damaged by storm or present a navigation hazard.

These and other aspects of the invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic elevation of a well head base and receiver being lowered from a floating vessel into a hole which is being drilled in an underwater formation;

FIG. 2 is an enlarged elevational view of the well head base in its final position on the ocean floor;

FIG. 3 is a fragmentary plan view of the well head base taken on line 33 of FIG. 2;

FIG. 4 is a schematic and fragmentary elevation of the elongated conductor supported by buoyant chambers spaced along its length, the conductor extending from the receiver to the floating vessel;

FIG. 5 is an enlarged schematic and fragmentary elevation, partly in section, showing the sealing mechanism at the lower end of the conductor, the flexible section in the lower portion of the conductor, and the detail of how one of the buoyant chambers is secured to the conductor;

FIG. 6 is a view taken on line 66 of FIG. 5; and

FIG. 7 is a fragmentary schematic elevation, partly in section, showing the presently preferred embodiment of the invention, in which the upper end of the conductor is secured to the floating vessel and provided with a slip joint to permit vertical displacement of the vessel with respect to the lower portion of the conductor.

Referring to the drawings, FIG. 1 shows a well head base 18 supported by support or guide lines 19, and being lowered by the support or guide lines in a body of water 20 from a floating drilling barge 21 toward a well 22 being drilled from the barge in an underwater formation 23. The upper ends of the support or guide lines may be controlled by suitable means, such as winches (not shown). Once the well head base is anchored, as described below, the winches, which are powered through torque converter transmissions (not shown) are used to maintain constant tension in the support or guide lines to preclude their fouling and to aid in guiding equipment down them, as is also described below. The barge is anchored over the well by a plurality of suitable anchor lines 24 extending in opposite directions from the barge and connected to anchors (not shown).

A draw works 25 and a power unit 26, which may be of conventional type, are mounted on the barge to operate the hoisting cable 27 carried over a crown block 28 located at the upper end of a derrick 29. The travelling end of the hoisting cable carries a travelling block 30 and a hook 31 which supports a swivel joint 32. A kelly joint 33 extends downwardly from the swivel through a kelly bushing 34 in the center of a rotary table 36 mounted on gimbals (not shown) in a manner similar to that described in US. Patent 2,606,003. The rotary table is supported on a platform 37 directly over a cellar 38 which may be located in the center of the barge as illustrated. Power is supplied to the rotary table through a shaft 39 turned by a rotary table power unit 40.

A string of drill pipe 41 is connected to the lower end of the kelly and extends down through the cellar, a central opening 42 in the well head base (see FIG. 3), the water and into the well. A drill collar 43 and an underreamer drill bit 44 are attached to the lower end-of the drill pipe for boring the well to a diameter slightly larger than the outside diameter of a casing or anchor 45 which is welded at its upper end to the well head base in the central opening of the well head base, and which projects downwardly from the well head base. One or more blowout preventers 45A are attached to the upper end of the casing 45 and extend above the top of the well head base. A mandrel or receiver 458 in the form of relatively short section of pipe approximately the same diameter as the casing, is attached at its lower end to the blow-out preventers. The blow-out preventers are of conventional type so that the well may be closed off with drill pipe in it or out of it. The blow-out preventers are actuated through a control line 45C which extends from the blowout preventers to the floating vessel.

During the stage of the drilling operation shown in FIG. 1, drilling fluid or seawater is pumped down the drill pipe to wash cuttings out of the Well as drilling proceeds, no attempt being made at this time to obtain return circulation.

As shown in FIG. 2, once the well is drilled to a sufficient depth to receive the casing, the well head base is lowered from the barge by means of guide lines so that the casing slides down around the drill pipe and into the well, the bottom of the well head base resting on the earth formation around the upper end of the well. During this operation, the blow-out preventers are held open so that the casing slides freely down the drill pipe. Preferably, the conductor pipe is of sufticient length to be firmly anchored in the formation by cementing it in place by well known techniques. The under-reamer may be retracted and the drill pipe, drill collar and drill bit removed from the well bore, or drilling may be continued without removing the drill bit from the well until some later period of the drilling operation.

As shown most clearly in FIGS. 2 and 3, the well head base is a relatively flat and wide structure which is hexagonal in shape, as viewed in plan. The periphery of the bottom of the well head base is made up of six sections 46 of I-beams of equal length welded together end to end to form a hexagon. A separate vertical brace 47 is welded to the junctions of the ends of each of the I- beam sections 46 and connects the bottom of the well head base to the top of the well head base, which is also for-med of six sections 48 of I-beams welded together end to end to form a hexagon identical in size and shape to the bottom of the well head base.

An upper set of horizontal and radially extending braces 50 extended from the junctions of the ends of the peripheral sections of the top of the well head base to terminate at the outside diameter of the upper end of the casing, to which they are welded. A lower set of horizontal radially extending braces 51 are similarly welded to the junctions of the ends of the peripheral sections of the bottom of the well head base and are welded at their inner ends to the casing in the plane of the bottom of the well head base. A set of six diagonal braces 52 extending upwardly and inwardly from the junctions of the ends of the peripheral sections of the bottom of the well head base are welded at their lower ends to the base bottom and at their upper ends to the casing.

A plurality of separate water tight compartments 53 are attached to the interior of the well head base so that it may be floated and towed to any desired location. A pad-eye 54 welded to one of the radial sections in the top of the well head base provides a convenient means for attaching a tow line (not shown).

An annular circular plate 55, is disposed around the central opening 42 in the well head base. The plate 55 is welded to the top surfaces of the radially extending braces in the top of the well head base. Three cones 57 spaced at 120 intervals on a common circumference are welded to the top surface of the circular plate. A separate pad-eye 58 is welded to the upper end of each cone, and the lower end of a separate guide line 19 is connected to each pad-eye with a swivel 9 a d a Shackle A drilling operation as illustrated in FIG. 1 is commenced with the well head base as follows: 7 The Well head base is towed to the desired location, and the drilling barge is firmly anchored over the well site. The guide lines are connected to the well head base cones, and the tow line is disconnected from the well head base. The buoyant compartments in the well head base are then flooded either by puncturing the wall of the compartments or by opening valves (not shown).

The upper ends of the guide lines being controlled from the drilling barge, the well head base compartments are flooded until the base has a slight negative buoyancy. Suitable handling lines (not shown) are then attached to the base and it is then pulled to the position shown in FIG. 1, i.e., under the cellar in the barge, where it is held by the guide lines at a shallow depth below the cellar. The drill bit, drill collar and drill pipe are then made up on the barge and lowered through the receiver, blow-out preventers, which are open, and the casing. The drilling operation then proceeds as described above until a suflicient depth is reached to permit the casing to be lowered into the well and allow the bottom of the well head base to rest on the ocean floor. Preferably the casing is then cemented in place.

For operation in areas where the water depth is less than the overall length of the desired amount of casing and the well head base, the base is anchored by a slightly different procedure. The base is maneuvered into the position shown in FIG. 1 without the casing, blow-out preventers and receiver. A joint of casing is inserted to the opening of the base and supported by suitable means from the barge so that the lower end of the casing is flush with the bottom of the base. The base and casing are then lowered simultaneously, successive joints of casing being added, until the base is resting on the bottom, and the upper end of the casing extends up into the barge above the water level. Using salt water without return circulation, sufficient hole is drilled with the bit and underrea-mer to receive the desired amount of easing. Salt water is then displaced with mud to keep the hole open, and the top of the casing is lowered a few feet into the upper end of the hole. The drill pipe and bit are withdrawn, and the remainder of the casing is then run down into the hole. The blow-out preventers and receiver are flanged to the upper end of the casing, which is then lowered so that the blow-out preventers rest on the top of the well head base. The drill pipe is also lowered within the upper end of the casing so that is extends down below the blow-out preventers. When the casing reaches its lowermost position, the blow-out preventers are closed on the drill pipe and the casing cemented in place by pumping cement down through the drill pipe and forcing cement into the annular space between the casing and the hole. The drill pipe is then removed and the cement is allowed to set.

At this point it is necessary to have apparatus which will permit equipment to be guided accurately to the Well bore. Such apparatus is shown in FIGS. 2 through 6.

Referring to FIGS. 4 and 5, a guide assembly 64 is adapted to slide up and down the guide lines and carry with it a guide bracket 65 adapted to slide up and down with respect to the guide assembly. The guide assembly includes a horizontal circular hoop brace 66 at its lower end which is made up of three equal segments welded at each end to the lower ends of three hollow vertical guide posts 67. A respective guide line passes through each guide post. The upper end of each guide post is threaded and a separate guide post cap 68 having an outside diameter slightly greater than the diameter of the guide post is screwed on to the upper end of each guide post. Each guide post cap has a central opening 69 to accommodate a respective guide line. A separate hollow guide assembly cone 70 is welded to the lower end of each guide post and adapted to nest on a respective well head base cone so that the guide assembly is centered above the central opening in the well head base when the guide assembly is lowered to rest on it, and so that forces and loads of the guide assembly are transferred to the well head base.

The guide bracket includes three vertical sleeves 71, each sleeve having an inside diameter to make a sliding rit over a respective guide post. The outside diameter of each sleeve is substantially the same as the outside diameter of each guide post cap, which limits the upward travel of the equipment bracket on the guide assembly. A separate, horizontal upper arm 72 is welded at its outer end to each guide post and extends radially and inwardly for a relatively short distance toward the center of the guide assembly. A separate horizontal lower arm 73 is similarly attached to each guide sleeve below a respective upper arm.

The inner end of each guide bracket arm is welded to the exterior of a conductor seal housing $0, which has an upright central bore 82 through it adapted to fit over the upper end of the receiver. A short, vertical tubular coupling 84 is welded around the upper end of bore 82, which is of substantially the same diameter as the internal bore of the receiver. The lower end of a strong heavy-wall, flexible section of rubber hose 86 is connected by a clamp 88 to the coupling, and the upper end of the rubber hose is connected by clamp 90 to the lower end of an elongated conductor 92 which is made up of a plurality of pipe sections 93 threaded at each end and held together by external collars 94 which form external shoulders 95 (see FIG. 5) on the conductor. The rubber hose section may be omitted if the length of the conductor is suflicient to provide the necessary flexibility to accommodate the random motion of the barge. A separate annular buoyant chamber 96 is disposed around the conductor under each collar. With this arrangement the conductor is free to flex laterally within its elastic limit and not be constrained by the buoyant chambers.

As shown in FIG. 4, one end of a conductor supporting cable 98 is attached to a lug 99 welded to the upper end of the conductor. The other end of the conductor cable extends upwardly from lug 99 past a roller 100 to a winch (not shown) on the drilling barge. The winch is powered by a torque converter transmission so the supporting cable is held under constant tension to support the conductor, and yet leave the floating vessel free to move vertically with respect to the conductor. One or more additional conductor cables and winches may 'be provided symmetrically around the upper end of the conductor to provide a balanced support for it. The upper end of the conductor has a lateral conduit 108 through which drilling mud returns to a mud pit 84. An annular guard ring 109 is attached to the barge cellar walls and makes a close sliding fit around the conductor below lug 9'9 and permits relative vertical movement between the barge and conductor, while at the same time limiting relative lateral movement between the barge and conductor.

The lower end of the conductor is adapted to be releasably sealed to the receiver by means of a heavy-wall rubber sleeve 110 (see FIG. 5) mounted within the conductor seal housing. Starting at the top of the housing, the central bore 82 is of substantially the same diameter as the internal diameter of the receiver. The bore is then stepped to an increased diameter to form an upper section 112 and then increased again to form a central section 114. The upper end of the seal sleeve 110 is molded into an annular groove 116 formed in the shoulder between bores 112 and 114. Below central section 114 of the central bore in the seal housing, the bore is stepped down to form a section 118 of the same diameter as section 112. The lower end of the seal sleeve is molded into an annular groove 120 in the shoulder formed between sections 114 and 118. The lower end of the bore has a section 122 which tapers downwardly and outwardly to match a similar surface on the upper end of the blow-out preventer. A conduit seal control line 124 extends down from the floating vessel and is adapted to supply fluid pressure to an annular spacing 125 formed between the seal sleeve and the seal housing. With the seal housing disposed over the receiver as shown in FIG. 5, fluid pressure applied by line 124 forces the sleeve to extend inwardly and seal around the receiver, providing a closed path for the flow of drilling fluid back to the floating vessel.

The installation and use of the conductor is as follows:

Once it is determined that return circulation is necessary, or that equipment must be removed from and returned to the well, the guide lines 19 are threaded through the hollow guide posts of the guide assembly on the barge. The upper end of each respective guide line is then disposed over a separate winch (not shown) powered by a torque converter transmission, and held taut. The conductor seal housing, the section of rubber hose, and the first section of casing, all of which are previously made up on the barge, are then held suspended in the cellar of the floating vessel. The first buoyant chamber, which is to be the lowest chamber once the conductor is sealed in the position shown in FIG. 4, is slipped on to the upper end of the section of conductor pipe connecte to the rubber base. A collar and the next section of conductor pipe are then coupled to the upper end of the section of conductor pipe. This process is repeated, making the conductor up to the required length and lowering it as sections of the conductor pipe collars and buoyant chambers are added. This procedure continues until the conductor pipe is of the length shown in FIG. 4. At this time, the guide assembly cones nest over the well base cones and center the conductor seal housing over the upper end of the receiver. The conductor is then lowered a short distance, permitting the sleeve 71 to slide down the guide post so that the seal housing comes to rest in the position shown in FIGS. 4 and 5. Fluid pressure is then supplied to the seal housing through line 124 to seal the conductor pipe to the receiver.

The placing of the conductor in the position shown in FIGS. 4 and 5 as described above, may be achieved with the drill pipe either in or out of the well, the drill pipe being disconnected from the kelly and the conductor being stripped down over it in the event the drill pipe is left in the well.

With the apparatus in the position shown in FIGS. 4 and 5, drilling proceeds in a routine fashion, additional casing 139 and blow-out preventers (not shown) being guided through the conductor pipe, and set as drilling proceeds to greater depths.

The advantage of the apparatus of this invention is that repeated trips in and out of the well with drilling or other equipment may be made through the conductor pipe, so that the flexible guide means are necessary primarily only for the relatively infrequent occasion for sealing the lower end of the conductor to the receiver.

The well site may be temporarily abandoned by several different procedures, the particular procedure depending on the conditions.

If it is desirable to leave the well site in the shortest possible time, say, due to a sudden storm, and drilling is in progress, several sections of drill pipe are quickly removed and the upper end of the drill pipe is plugged. The drill pipe is then lowered until the drill bit is almost on bottom and the blow-out preventers are closed around it. The blow-out preventer control line is sealed under pressure, buoyed and cast ofl. The upper portion of the conductor is removed below the water surface, and stored on the floating vessel, as is the conductor supporting cable. The guide lines and control line 124 are buoyed and cast off from the floating vessel. The barge is then moved away from the conductor. The buoys mark the well site for the return of the barge when drilling is to be resumed.

Ordinarily, suflicient advance notice is available to allow time to leave the well site so that all or most of the drill pipe can be retracted and so that the conductor can be released from the receiver and withdrawn to the floating vessel. Under these conditions, the blow-out preventers are left closed and the control lines, along with the guide lines, are left buoyed as before.

FIG. 7 shows the presently preferred embodiment of the invention in which the apparatus is adapted to be abandoned temporarily and in a relatively short period of time, such as might be required due to the sudden occurrence of a storm. The conductor 92 is secured by the conductor seal housing 80 to the well head receiver 45B as described with respect to FIG. 5. The upper end of the conductor terminates in a slip joint 139 located a substantial distance below the surface of the water to provide safe navigational clearance for the drilling barge and other vessels which might be in the area, and to be below any substantial wave effects. An annular buoyant chamber 140 is connected to the upper end of the conductor below the slip joint 139 and provides suflicient buoyancy to support the conductor in the upright position shown. The

control lines

45C and 124 for the blowout preventers and conduit seal housing, respectively, are secured by a clamp 141 to the chamber and extend on to the barge.

An annular extension conduit seal housing 142 is secured to the upper surface of the buoyant chamber around the central opening in the chamber. The lower end of an upright extension conduit 144 extends down into the conduit seal housing and the opening in the buoyant chamber. The conduit seal housing is adapted to be sealed firmly to the extension conduit by an internal rubber sleeve 146 which is secured at each end to the housing and actuated by fluid pressure applied through a line 148 extending to the drilling barge. A horizontal stop piston 150 is disposed in a cylinder 151 on the upper end of the conduit seal housing, and is urged inwardly by a compression spring 152 against the extension conduit sothe piston will engage an annular groove 154 near the lower end of the extension conduit when the conduit is raised, and thereby prevent the conduit from being pulled inadvertently up out of the conduit seal housing. Fluid pressure may be applied through a line 156 to hold the locking piston outwardly against the spring to permit the withdrawal of the extension conduit when desired.

A slidable tube 158 is disposed in, and projects upwardly from, the upper end of the extension conduit. A packing gland 160 in the upper end of the extension conduit may be adjusted by bolts 162 to provide the desired sealing between the tube and the extension conduit, i.e., the gland is adjusted to permit the tube to slide freely with the vertical motion of the drilling barge, and yet be tight enough to prevent leakage of drilling mud. An external gutter 164 is on the extension conduit under the packing gland to catch any drilling mud which might leak through the gland. A suitable sump pump (not shown) has its intake disposed in the sump to carry away any drilling mud which might be collected in the gutter.

The upper end of the sliding conduit is supported by a cable 166 which is secured by suitable means to the barge. The drill pipe extends coaxially down through the tube, the extension conduit, the conductor, and into the well, as described previously with respect to FIG. 5.

A mud return nipple 168 on the upper end of the tube is connected by flanges 170 to a mud return hose 172 which discharges on to a shaker and screens 174, which are disposed above a collector 176 which returns mud to the mud pit.

The operation of the apparatus shown in FIG. 7 is relatively simple. With the well head base located as shown and described with respect to FIG. 5, the conductor and conductor seal housing are lowered down the guidelines and sealed to the receiver conduit as shown in FIG. 7, the upper end of the sliding tube being retained on the drilling barge. Fluid pressure is applied to the extension conduit seal so that the extension conduit is firmly held with respect to the buoyant chamber. Drill pipe is then lowered down the tube and into the well, and drilling operations are conducted in a substantially conventional fashion, i.e., drilling mud is circulated down the drill pipe as the pipe is rotated, and the mud returns back up the annular space between the drill pipe, the conductor, and the tube. The crnud flows out of the mud return nipple, through the mud return hose and on to the shaker screens. As the drilling barge is moved up and down by wave action, the sliding tube and shakers and screens move with it so that there is always a constant elevation between the mud return nipple and the shaker screens to provide for the steady and uninterrupted return of the drilling mud. The packing gland between the tube and the extension conduit permits tne tube to slide and yet maintain a fluid tight seal with the extension conduit. The packing gland and its adjustment are located above the water level so that its operation can be easily observed and so that it can readily be adjusted or repaired. At any time it may be desired, the fluid pressure applied to the extension conduit seal housing can be released to permit the extension conduit to be adjusted to any required height, the locking piston 150 and the annular groove in the lower portion of the extension conduit preventing the inadvertent removal of the extension conduit from its sealing housing.

If it becomes necessary to leave the well site quickly, the drill pipe is either completely removed from the hole, or else a suflicient length is removed from its upper end to permit it to be plugged and lowered back into the well so that its upper end is well below the surface of the water. The blow-out preventers are closed to shut in the well, and the mud return nipple is disconnected from the mud return hose. Pressure is released from the extension conduit seal housing and the extension conduit and tube are lowered from the drilling barge until the annular gutter on the extension conduit rests on the upper surface of the extension conduit seal housing, and the drilling mud return nipple rests on the upper end of the extension conduit.

Control lines

45C, 124, 148 and 156 are sealed, disconnected from the barge, buoyed and cast olf. Supporting cable 166 and the guide lines are buoyed and cast off, so the barge can then be moved from the loca- -tion.

When drilling is to be resumed, the barge is returned to and anchored over the well site, being guided by the buoys. The control lines, guide lines and cable 166 are picked up and arranged on the drilling barge as described previously. The slidable tube is then raise-d by cable 166. An annular external lip 178 on the lower end of the tube engages an internal annular lip 1 at the upper end of the extension conduit and raises the extension conduit to the desired position. Line 148 is re-connected to the source of fluid pressure on the barge, and pressurized to lock the extension conduit in the required position. The tube is again supported by line 166 as shown in FIG. 7, and the drill pipe, if left in the well, is retrieved by a conventional fishing operation, and drilling is then resumed as described above.

As can be appreciated from the foregoing description, the well can be abandoned in a relatively short time, and drilling operations can be resumed with a minimum amount of difficulty.

We claim:

1. 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 disposed over the Well site, a rotary drilling rig including a rotary table mounted on the vessel, an elongated hollow conductor extending between the vessel and the formation, the conductor being made up of an upper section and a lower section, remotely controllable coupling means near the bottom of the water body for sealing the two conductor sections together, the upper end of the upper section being spaced below the rotary table to have a free space between them and the lower end of the lower section of the conductor being disposed in the well, means for raising and lowering the upper section of the conductor, means for finmly anchoring and sealing the lower end of the lower section of the conductor to the formation, a blow-out preventer disposed in the conductor below the coupling means, a buoyant support attached to the upper portion of the conductor, a slip joint in the conductor above the buoyant chamber, means for changing the effective length of the upper section of the conductor, means for attaching the conductor to the vessel above the slip joint, a drill pipe extending down through the rotary table into the conductor, means for pumping drilling mud down through the drill pipe, a mud screen mounted on the vessel, a lateral conduit connected at one end to the upper portion of the conductor and having its other end disposed over the screen, an elongated laterally flexible support member attached at its lower end to the lower section of the conductor, and terminating at its upper end at the vessel, and means interconnecting the upper section of the conductor and the support member so that as the lower end of the upper sec tion of conductor is lowered, it is constrained by the support member to register with the upper end of the lower section of the conductor.

2. 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 disposed beneath the vessel so the upper end of the conductor 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 to the anchor to form through the opening in the anchor a continuous conduit between the well and the vessel, means for moving equipment to and from the well through the conductor, remote control means for releasing the coupling means from the water surface to permit the conductor and anchor to be separated from each other, and means for guiding the conductor from the floating vessel to the anchor so the coupling means connects to the anchor to form the said continuous conduit.

3. 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 disposed over the well site, an elongated casing disposed beneath the vessel, an elongated laterally flexible support member attached at one end to the casing and terminating at its other end at the floating vessel, means for lowering the casing from the vessel toward the formation with the support member, means for guiding the casing to the formation so the casing enters the well, means forming an elongated enclosed passage between the vessel and the well and collinear with the casing, means for firmly anchoring and sealing the lower portion of the passage forming means to the formation, and means for moving equipment between the vessel and well through the passage.

4. 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 disposed beneath the vessel so that the upper end of the conductor 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 to the anchor to [form through the opening in the anchor a continuous conduit between the well and the vessel, means for moving equipment to and from the well through the conductor, means for releasing the coupling means from the water surface to permit the conductor :and anchor to be separated from each other, and means for guiding the conductor from the floating vessel to the anchor so the coupling means connects to the anchor to form said continuous conduit.

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 disposed over a well site, an elongated hollow conductor disposed beneath the floating vessel so that the upper end of the conductor is connectable to the vessel, means sealing the lower end of the conductor to the well, a slip joint in the conductor below the water surface, said slip joint being of such a length so as to permit the lowering of the upper end of the conductor from an operating position to a position substantially below the surface of the water, and a buoyant support attached to the conductor below the slip joint, said buoyant support having sufficient buoyancy to support the portion of the conductor disposed below the slip joint in a substantially vertical position.

6. 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 disposed over the well site, an elongated hollow conductor disposed beneath the floating vessel with the upper end of the conductor terminating in the vicinity of the vessel, means sealing the lower end of the conductor to the well, a slip joint in the conductor below the water surface, said slip joint being of such a length as to permit the lowering of the upper end of the conductor from an operating position to a position substantially below the surface of the water, a buoyant support attached to the conductor below the slip joint, said buoyant support having sufficient buoyancy to support the portion of the conductor disposed below the slip joint in a substantially vertical position, and a blow out preventer in the conductor below the buoyant support.

7. 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 disposed over the well site, an elongated hollow conductor disposed beneath the floating vessel, the conductor including a lower section and an upper section, the lower section being beneath the water surface and the upper section being slidable within the upper portion of the lower section and having its upper end terminating in the vicinity of the vessel, whereby .the upper section may be slidably lowered within the lower section so that the upper end of the upper section is lowered from an operating position to a position substantially below the surface of the water, means sealing the lower end of the lower section of the conductor to the well, a buoyant support, and means attaching the buoyant support to the upper portion of the lower section of the conductor so as to maintain the lower section of the conductor in a substantially vertical position.

8. 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 disposed over the well site, buoyant support means within the water and below the bottom of the vessel, an elongated hollow conductor disposed beneath the floating vessel, said conductor including a lower section and an extension section, the extension section being slidable within the lower section and having its upper end terminating in the vicinity of the vessel, means sealing the lower end of the lower section of the conductor to the well, means connecting the upper end of the lower section of the conductor to the buoyant support means so as to maintain the lower section in a substantially vertical position, and means for selectively locking the extension section in various positions against its longitudinal movement within the lower section so that the overall length. of the conductor is selectively variable between a maximum length when the conductor is in its operating position and a minimum length when the upper end of the extension section is a substantial distance below the surface of the water.

9. Apparatus in accordance with claim 8 further including means for remotely operating the locking means.

10. 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 disposed over the well site, a drilling mud shaker screen on the vessel, an elongated hollow conductor disposed beneath the floating 'vessel, said conductor including a lower section and an extension section, the extension section being slidable within the lower section and having its upper end terminating in the vicinity of the vessel, means sealing the lower end of the lower section to the well, buoyant support means, means connecting the lower section to v the buoyant support means so as to maintain the lower section in a substantially vertical position, means for selectively locking the extension section in various longitudinal positions within the lower section so as to selectively vary the overall length of the conductor between a retracted length in which the upper end of the extension section is a substantial distance below the surface of: the water and an operating length, a tubular section slidably fitted Within the upper end of the extension section, and a lateral mud line having one end attached to the upper portion of the tubular section and its other end open ing over the shaker screen.

11. Apparatus, for carrying out operations such as drilling and working in a well in a formation underlying a body of water from a vessel floating on the water, comprising an elongated hollow conductor extending upwardly from the formation, a slip joint in the conductor which divides the conductor into an upper portion and a lower portion, said slip joint being positioned along the conductor so as to permit the lowering of the upper end of the upper conductor portion from an operating position to a position a substantial distance below the surface of the water, means sealing the lower end of the lower conductor portion to the formation, buoyant support means, and means for connecting buoyant support means to the upper end of the lower conductor portion so as to maintain the lower conductor portion in a substantially vertical position.

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 disposed beneath the vessel so the upper end of the conductor terminates at the vessel, an anchor including an opening therethrough communicating at one end with the upper end of v the well, means for moving the conductor down and up to bring the conductor lower end into and out of a coupling position with the anchor, remotely actuatable coupling means for connecting the lower end of the conductor, when in the coupling position, to the anchor to form through the opening in the anchor a continuous conduit between the well and the vessel, an 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 and guide member so that as the conductor is lowered it is constrained by the guide member to cause the conductor lower end, coupling means, and anchor to be in the coupling position, remote control means for actuating the coupling means from the water surface to permit the conductor and anchor to be connected to and separated from each other, and means for moving equipment to and from the well through the conductor when it is connected to the anchor.

13. Apparatus according to claim 12 which includes buoyant supporting means for the conductor.

14. Apparatus according to claim 12 which includes a plurality of longitudinally spaced buoyancy chambers attached to the conductor.

15. Apparatus according to claim 12 in which conductor includes a slip joint to permit one part of the conductor to move longitudinally with respect to another part.

16. 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 disposed beneath the vessel so the upper end of the conductor terminates at the vessel, a casing disposed in the well, means for sealing the casing in the well, blow-out preventer means connected in the casing, remote control means for actuating the blow-out preventer means, means for moving the conductor down and up to bring the conductor lower end into and out of a coupling position with the casing, remotely actuatable coupling means connectable between the lower end of the conductor, when in the coupling position, and to the casing so as to provide fluid communication therebetween, an 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 and guide member so that as the conductor is lowered it is constrained by the guide member to cause the conductor, coupling means, and casing to be in the coupling position, remote control means for actuating the coupling means from the water surface to permit the conductor and casing to be connected to and separated from each other, and means for moving equipment to and from the well through the conductor when it is connected to the casing.

17. 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 rotary drilling rig including a rotary table mounted on the vessel, a generally upright elongated hollow conductor disposed beneath the vessel so the upper end of the conductor terminates at the vessel below the rotary table to leave a free space between the table and the upper end of the conductor, an anchor including an opening therethrough communicating at one end with the upper end of the well, means for moving the conductor down and up to bring the conductor lower end into and out of a coupling position with the anchor, remotely actuatable coupling means for connecting the lower end of the conductor, when in the coupling position, to the anchor to form through the opening in the anchor a continuous conduit between the well and the vessel, a laterally 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 and guide member so that as the conductor is lowered it is constrained by the guide member to cause the conductor, coupling means, and anchor to be in the coupling position, remote control means for actuating the coupling means from the water surface to permit the conductor and anchor to be connected to and separated from each other, and means for moving equipment to and from the well through the conductor when it is connected to the anchor.

18. 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, 21 well head base having an opening through it, an elongated support member attached at one end to the base and terminating at its other end at the floating vessel, means for lowering the well head base from the vessel toward the formation by the support member, means for positioning the base with respect to the formation so the base opening is aligned with the well, an elongated conduit extending downwardly from the vessel, means for guiding the conduit through the base opening and into the Well, means for firmly anchoring the lower portion of the conduit to the formation, and means for moving equipment between the vessel and well through the conduit.

1?. 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 well head base having an opening through it, an elongated laterally flexible support member attached at one end to the base and terminating at its other end at the floating vessel, means for lowering the 'well head base from the vessel toward the formation by the supporting member, means for positioning the base with respect to the formation so the base opening is aligned with the well, an elongated conduit extending downwardly from the vessel, means for guiding the conduit through the base opening and into the well, means for firmly anchoring the lower portion of the conduit to the formation, means for moving equipment between the vessel and well through the conduit, and a buoyant support connected to the conduit.

20. 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 well head base having an openingthrough it, an elongated laterally flexible support member attached at one end to the base and terminating at its other end at the floating vessel, means for lowering the well head base from the vessel toward the formation by the support member, means for positioning the base with respect to the formation so the base opening is aligned with the well, an elongated conduit extending downwardly from the vessel, means for guiding the conduit through the base opening and into the well, means for supporting the conduit at the well head base, means for firmly anchoring the lower portion of the conduit to the formation, and means for moving equipment between the vessel and well through the conduit.

21. 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 disposed beneath the vessel so the upper end of the conductor terminates at the vessel, an anchor including an opening therethrough communicating at one end with the upper end of the Well, means for moving the conductor down and up to bring the conductor lower end into and out of a coupling position with the anchor, coupling means for connecting the lower end of the conductor, when in the coupling position, to the anchor to form through the opening in the anchor a continuous conduit between the well and the vessel, an 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 and guide member so that as the conductor is lowered it is constrained by the guide member to cause the conductor, coupling means, and anchor to be in the coupling position, and means for moving equipment to and from the well through the conductor when it is connected to the anchor.

References Cited UNITED STATES PATENTS 2,628,818 2/1953 Graham -9 339,630 4/1886 Douglas 166-46 X 2,248,015 7/1941 Armstrong 175-9 X 2,676,787 4/1954 Johnson 175-7 2,684,575 7/1954 Pryor et al 175-8 X 2,810,442 10/1957 Tausch 166-.5 X 2,836,247 5/1958 McCulloch 166-46 1,524,677 2/1925 Thompson 285-302 1,764,488 6/1930 Zublin 166-241 1,766,628 6/1930 Grant 175-10 2,512,783 6/1950 Tucker 175-8 2,606,003 8/1952 McNeill 175-7 2,610,028 9/1952 Smith 166-224 2,476,309 7/1949 Lang 175-8 2,808,229 10/1957 Bauer et al 175-7 CHARLES E. OCONNELL, Primary Examiner.

R. E. FAVREAU, Assistant Examiner.

Claims

2. APPARATUS FOR CARRYING OUT OPERATIONS SUCH AS DRILLING A WORKING IN A WELL IN A FORMING UNDERLYING A BODY OF WATER COMPRISING A FLOATING VESSEL, A GENERALLY UPRIGHT ELONGATED HOLLOW CONDUCTOR DISPOSED BENEATH THE VESSEL SO THE UPPER END OF THE CONDUCTOR 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 TO THE ANCHOR TO FORM THROUGH THE OPENING IN THE ANCHOR A CONTINUOUS CONDUIT BETWEEN THE WELL AND THE VESSEL, MEANS FOR MOVING EQUIPMENT TO AND FROM THE WELL THROUGH THE CONDUCTOR, REMOTE CONTROL MEANS FOR RELEASING THE COUPLING MEANS FROM THE WATER SURFACE TO PERMIT THE CONDUCTOR AND ANCHOR TO BE SEPARATED FROM EACH OTHER, AND MEANS FOR GUIDING THE CONDUCTOR FROM THE FLOATING VESSEL TO THE ANCHOR SO THE COUPLING MEANS CONNECTS TO THE ANCHOR TO FORM THE SAID CONTINUOUS CONDUIT.