US2929610A - Drilling - Google Patents

Description

March 22, 1960 H. STRATTON 2,929,610

DRILLING Filed Dec. 27, 1954 s Sheets-Sheet 1 FIG.

"m W a A IN V EN TOR. HAL STRATTON MMeM A TTORNEYS March 22, 19 60 H. STRATTON DRILLING 5 Sheets-Sheet 2 Filed Dec. 27. 1954 FIG 2.

P 40 l I INVENTOR. HAL STRATTO/V Vii H III March 22, 1960 H. STRATTON 2,929,510

DRILLING Filed Dec. 27, 1954 5 Sheets-Sheet 3 FIG. 3.

Rx 121M525. HAL STRATTON WJZJAMM A 7' TORNE KS H. STRATTON DRILLING March 22,1960

Filed D90. 27, 1954 FIG. 4.

5 Sheets-Sheet 4 INVENTOR. HAL STRATTON March 22, 1960 H. STRATTON DRILLING 5 Sheets-Sheet 5 Filed Dec. 27. 1954 INVENTOR. HAL .STRATTON ATTORNEYS DRILLING Hal Stratton, La Habra, Calif., assignor to Shell Oil Company, Continental Oil Company, both of Los Angeles, Calif., both corporations of Delaware, The Superior Oil Company and Union Oil Company of Caiilornia, both of Los Angeles, Calif., corporations of California ice Patented-Mar. 22, 1960 duit into the well. Thereafter the drill pipe, drill bit and underreamer are withdrawn up through the well con- 7 ing the well to the required depth, the well conduit is Application December 27, 1954, Serial No. 477,307

9 Claims. (Ci. 2551.S)

This invention relates to underwater drilling and more particularly to methods for setting a casing or a well conduit in an underwater well.

At the present time underwater or off-shore well drilling is accomplished from stationary structures rigidly anchored to the underwater formation. These structures provide static bases for drilling equipment and are satisfactory for relatively shallow water, for example, depths of 50 or less. However, for deeper water, for example, depths of several hundred feet, stationary structures are not always economically practical. Furthermore, the structures are sometimes permanent installations which may become navigation hazards. United States Patent 2,808,229 issued October 1, 1957 on application Serial Number 468,214 filed November 12, 1954, describes in detail apparatus and methods for drilling underwater wells from a floating vessel to overcome the disadvantages of static structures. In that co-pending application there is described a receiver assembly connected to the upper end of a well conduit projecting from an underwater well. The receiver assembly is used to guide drilling equipment from the floating vessel into the well. This invention is concerned with methods and apparatus for positioning the well conduit or pipe and receiver assembly in an underwater well.

One technique for accomplishing this objective is described in co-pending application Serial No. 481,529 filed January 13, 1955, and involves drilling the conduit into the formation by providing cutting means on its lower end and rotating the conduit from the vessel much in the nature of a regular drill string. Many formations, however, are of such nature as to impair operations in this manner and to require more sophisticated drilling techniques for penetration. This invention solves this problem by the method of forming the well, or at least the upper portion of the well, in the formation with a drill pipe and thereafter working the well conduit or pipe down into the well over the drill pipe. The word formation is used herein to mean the ground forming and beneath the bottom of a water body.

Preferably, fluid is circulated out the lower end of the well conduit as it is lowered in the well to prevent drill cuttings from being forced up into the well conduit.

in a presently preferred form, the well is drilled with a drill bit and underreamer attached to the lower end of the drill pipe. After the well has been drilled to a depth slightly greater than the total length of well conduit to be positioned, the drill bit and underreamer are raised slightly ofi the well bottom to avoid sticking of the drill pipeby any material which may slough ofi the well Wall. With the drill pipe, drill bit and underreamer in the well, the well conduit is slipped down over the drill pipe and into the well, the drill pipe serving to guide the wellconduit to leave the well conduit in the well.

In some situations, for example, where the well wall tends to slough excessively it is desirable to run the well conduit into the well as the well is drilled. This invention also accomplishes this objective by providing method whereby the well conduit is releasably held around the lower portion of the drill pipe as the well is drilled, and is carried into the well as drilling proceeds. Upon drill released and the drill pipe is withdrawn.

In setting pipe in accordance with this invention drillingfiuid may be continuously circulated. In conventional procedure drilling fluid circulation is interrupted, i.e. discontinued while the well conduit is lowered. This sometimes allows the drilling mud to lose its proper physical condition and makes resuming subsequent working in the well difficult. Continuous circulation of the drilling fluid, when the well conduit is set in accordance with this invention, avoids this difficulty.

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

Fig. 1 is a schematic elevation, partly broken away, showing the position of the well conduit on the drill pipe after the well has been drilled but before the well conduit has been lowered into the well;

Fig. 2 is a schematic elevation, partly broken away, of the floating vessel and associated drilling equipment of Fig. 1 illustrating the position of the well conduit on the drill pipe after the well conduit has been lowered into the well;

Fig. 3 is an elevation, partly in section, of the upper end of the well conduit set in the well with a receiver assembly and a circulating head mounted thereon in sealed relationship;

Fig. 4 is a view taken on line 44 of Fig. 3;

4 Fig. 5 is a view taken on line 55 of Fig. 3;

Fig. 6 is a view taken on line 6-6 of Fig. 3;

Fig. 7 is a View taken on line 7-7 of Fig. 4;

Fig. 8 is a vertical section of an alternate arrangement of a well conduit illustrating an alternate method for positioning the well conduit in a well;

8 Fig.1 9 is an enlarged view taken on line 9-9 of Fig.

Fig. 10 is a vertical section of a modified form of the apparatus shown in Figs. 8 and 9.

Referring to Fig. 1, a floating vessel 10, such as a ship, is anchored by means of anchor lines 11, in a body of water over a formation 12 in which a well 13 is to be drilled. A drawworks 14 and power unit 15 which may be of conventional type, are mounted on the ship to operate a hoisting cable 16 carried over a crown block 17 located at the upper end of a drilling rig 18 erected on the deck of the ship. The traveling end of the hoisting cable carries a traveling block 19 and a hook 20 which supports a swivel joint 21. A Kelly joint 22 with a conventional Kelly valve 23, extends downwardly from the swivel through a Kelly bushing 24 in the center of a.v rotary table 25 mounted on gimbals in a manner such as described in U.S. Patent 2,606,003. The rotary table is supported by a platform 26 directly over a cellar 27 which may be located in the center of a ship as illustrated. Power is supplied to the rotary table through a shaft 28- tut ed b a ro ary ta le power unit 29 waste a 1 a A pressure circulating head 30 is releasably sealed to a receiver assembly 31 attached to the upper end ofa well conduit 32 hanging vertically beneath the cellar from a pair of guide lines 33 temporarily secured, at 33A to the cellar Wall. A string of drill pipe 34 is connected to'the lower end of the Kelly and extends downthrough the cellarycirculating. head, well conduit, and into the.

well. A drill bit 35, underreamer 36, and drill collars re, Q sdts Q he w nd of h 'd l r e l epressurec cul a asi remnants.eases in det ail below, between thefrdtatable,drill pipe and the. l 9 6 80 a when, the .9 ll il. ..t 1 in h W l 4% haun i i a d ll lsefi tlz 9r d 3 a be s m lated fiqm mi d teak. rj t 3 t i b a man al as. hwi h a inll ssf n'usi 1 .9 41 t he wi l t-(n h s cen al fl sw f 9W K9 2 d il p p and dr l ll r b we. ta P e asalaa a e'bs nen the r l Pi e nd thewell wall, out, the; circulating head, andupa flexible. drilling mud'return; hoseldz ex endingffrom the. circulat inghead to, the mudipi tf H I r I Thejrieceiven3; includes an upright sleeve 5 6 (see. Fig.

3.) disposed co axiallyt about the upper portion of thewell conduit; The sleeve is rigidly attached to the conduit,

for'example, by welding. A pair of diametrically opposed and radially extending guidejpost arms 58 are rigidly 9 tb-flwhfifinil fi a le e n e ien l the guide vpost arms are If beams mounted. with the V flanges of the horizontal. V A separate. upright cylindrical and hollow guide post59iswelded in amatching notchfiormednat the outer end of each. guide post Eaclrguide post extends from the bottombi its respective arm to a substantial distance above the A solid plug 60. is welded in the upper endof each guide post so that each plug is flush'with the upperencl ofits respective 'guide' post. A separate upright triangular plate 61. is 'welded'across the upper surfaces: qf eaqh plug and guide. post; and is providedwith a transverse bore 62. The lower ends of the two guideline cablesare'separately .attachedftothe upper end of a respeetivefguide post by nieans'of a swivel 63 connected to a shackle 6jlwhich is attache alto its respective guide pos t through thebore.

A pair of opposed elongated SHPROITHI'IIIQS, 69 are at- .tached' to the sleeve "56 un de r the: guide post and extend outwardly a substantial distance from the well. The

7 ,each other, e.g., by welding, after the well conduit is suspended in the position shown inFig. 1."Thi' ee externalaligning lugs 72B are welded at 120 intervals to the upper end of the well conduit below, and angularly displacedfrom the guide and landing plates (see Fig. 5). The cir'culating head 30 comprises a frusto-conical shell 73 (see Fig.*3 )"with its upper end connected-to a'well conduit seal housing 74, having an uprightjcylindrical wall 75. The lower end of an annular flexible well conduit seal 76 is friction fitted into an upwardly opening annular channel ,77 formed in thelower end of the well conduit seal housingbetvvecn an upwardly extending ring n men an'anriular bottom IosiirflfiA forithefhbus'ihg the housing Wall. The uppe 'nd'o'f tlie well'condiiit seal' is fritibu'fittedinto down A ardly opeiiing afinillar channel 79 fdrmed in the upper end (if-th vvell conduit seal housing between a downwardly extending ring '80 on an annular upper closure 80A for the housing and the in the wall of the well conduit seal housing so that hydraulic pressure may be applied by means of a hydraulic line (not shown) to the well conduit seal and force it to form a fluid-tight seal with the Well conduit. This also provides positive gripping means by which the circulating head is held down on the well conduit during drilling operations. The lower end of a drilling mud conduit 82 is sealed into the upper end of th'e well conduit seal housing. One'end of a drilling mud return nipple 83 is threaded through the drilling mud conduit wall. The other end of the nipple is connected tothe flexible drilling mud return line 42 (see Fig. 1) which extends to the mud pit 39 d in the vessel. r a

An aligning conduit 85 is co-axially disposed within the mud conduit so that its lower'end terminates just above the upper end; of the well conduit when thecirculating head is in the sealed position illustrated in Fig. 3. An outwardly extending flange 86 attachedto the-intermediate portion of the aligning conduit'is secured by means of b0lts'87 to a matching outwardly extending flange 88 provided on the upper end of the mud conduit. The inside. diameter or the aligning conduit is smaller than they inside diameter of the well {conduit and therefore serves to guide the drill bit into the well conduit and avoid catching of the bit on the upper end of the well conduit as the bit is lowered into drilling position.

1A drill pipe seal housing or body 90 having an outwardly turned flange; 91 at its lower end issecur'ed to airqoutwardly turned flange 92 at the upper end of the aligning. conduit by means of bolts' 93.' external diameter of the body is less than that of thewellconduit seal housing and the body' external diameter is reduced at 94fjust above the'body flange. The body isprovided with a relatively large first internal bore.9. 5 extends from the upper end'of the body down near the portion of the ,housing'which is of reduced external diameter. The bore is then stepped down to a smaller second boref96 for ashort distance, then is stepped down to athird bore 97 for a short distance, then is stepped down to a fourth bore 98 for a short distance, then stepped up to a fifth bore 99, slightly less than that of the third bore to extend to.

a point near the lower end of the body, and is then stepped up to a larger sixth bore. 100 which extends to the lower end of the body. v

A sleeve bearing 101, which may be lignurn vitae, for example, is disposed within the large boret' at the upper end of the body, the lower end of the bearing resting on the shoulder formed at the end of the first bore and its uppenend being flush with the upper end oi the body. The, inner diameter of the sleeye, bearing' is le ss,than that of the second bore. Theinner edgaer the'lower endof the annular sleeve bearing is beveled. at 102 to permitwater to'fiow up. through 5. lubricating inlet port 1-93 provided in the horizontal sectionfof the body. wall above the frediiced external diameter of thebo d y. A metal insert 104 having an external diameter at its upper endlslightly lessthan the internal diarnete rof the sleeve bearing is rotatably disposed within the sleeve bearing so that theupper end of the insert is below that oi thefbeariug. An external spiral groove10'5 in the insert wall permits water to be circulated byconvection and friction up from the lubricating inlet port tokeepthe insert cool and lubricated during rotation. A V

Theexternal diameter of the insert 104 is stepped down to a reduced diameter at the same-locationwhere the first bore ofthe body is stepped down to a reduced diameter to form' an external shoulder 106 on'the, insert which restson a thrust'ring bearing 107 carried in the shoulder for'medbetween the "third andfthehfourth bores, offthe body., The upperend of the insert is ,internaliythreaded at 108 toreceive a. threaded bushing 109. which has.an annular external groove 110 neanits-upper end and an outwardlysturned flange 1'11 which rests on theupper edge of the insert.. An 0 ring 112 in the annular groove effects a fluid tight seal between the bushing and the insert.

The insert 104 is provided with a relatively large internal first bore 113 at its upper end which tapers to a reduced second bore 114 near its intermediate portion, then tapers again to a reduced third bore 115 in its lower portion, tapers again to a reduced fourth bore 116 and then steps out to an increased fifth bore 117 to provide a lifting shoulder 118 on which there is disposed a cushion ring 119 which may be made of heavy rubber. An upper thrust ring bearing 120, which may be made of Micarta (a phenolic plastic), is disposed on the upper end of the bushing and supports a retaining ring 121 provided with a pair of diametrically opposed slots 122 in its periphery, each slot being adapted to receive a longitudinally movable locking pin 123. A fastening ring 124 is disposed on top of the upper end of the sleeve bearing and the body wall and is rigidly attached to the body wall by means of bolts 125. The inner periphery of the underside of the fastening ring is provided with a groove 126 which communicates with an annular space 127 formed between the upper thrust ring bearing, the upper end of the bushing, the fastening ring and the sleeve hearing. A plurality of vertical lubricating outlet ports 128 in the fastening ring connect with the groove 126 and permit the lubricating water to flow from the interior of the body.

A pair of horizontal bores 129 through the fastening ring house the locking pins. The bores are of reduced diameter at their outer ends to form a shoulder 130. A compression spring 131 is coaxially disposed around each locking pin and bears against a flange 132 attached to the inner end of each locking pin and bears against the shoulder of the locking pin bores. The outer ends of the locking pins extend out beyond the fastening ring and are each provided with a transverse pin 133 which holds a stop collar 134 around the outer end of each locking pin. A ring handle 135 is welded to the outer end of each stop collar to facilitate its operation.

An annular flexible drill pipe seal 136 is coaxially disposed within the insert and is supported at its upper end by a plurality of metal eyes 137 molded into the seal and held by corresponding hooks 138 formed integrally on a seal ring 139 secured to the underside of the bushing by means of bolts 140. The drill pipe seal has a relatively large first bore 141 at its upper end and tapers to a reduced second bore 142 at its lower end, and is sufficiently flexible to be expandable to a large enough diameter to permit the passage of drill pipe and drill collars. However, under ordinary drilling operations, the seal clamps tightly around the drill pipe or drill pipe joints so as to rotate with the pipe and effect a fluidtight seal.

An insert seal 143 is disposed in the annular space formed between the lower end of the insert 164 and the fifth internal bore 99 of the body. The insert seal is held up in position by means of an insert seal retaining ring 144 secured by means of bolts 145 to the shoulder formed between the fifth and sixth internal bores of the body.

.Referring to Fig. 3, an upper pair of diametrically opposed and radially extending guide brackets 147 (preferably short sections of relatively small I beams) are welded to the external surface of the drilling mud conduit on the circulating head. A separate sleeve 148 in the form of an upright, hollow, truncated, four-sided pyramid is attached to the outer end of each guide bracket by means of a pair of vertical, spaced plates 148A which are welded at one end to the sleeve and arranged at the other end to fit on each side of the guide brackets The plates are attached to the guide bracket by means of bolts 14?. A slot 150 (see Fig. 6) is provided in the sleeve wall between the two plates and a respective guide line 33 is-slipped into each sleeve 148 before the sleeve is bolted to the guide bracket -147.

A separate, outwardly extending plate- 151, curved'concave downwardly, is attached to the upper and outer edge of each guide sleeve to reduce the wear on the guide lines as the circulating head is raised and lowered.

A similar pair of lower guide brackets 152 are attached to the external surface of the aligning funnel 73 at the lower portion of the circulating head. A separate guide sleeve 153 is attached to the outer end of each lower guide bracket, the principal difference from the upper sleeves 148 being that the curved plate is omitted. The guide sleeves are adapted to slip on and off the guide post and accurately align the circulating head on the receiver assembly.

The well conduit 32 is positioned in the well by the method illustrated in Fig. 1 through Fig. 7 as follows:

rior to the lowering of the drill string or pipe 34, the well conduit and the supporting receiver assembly 31 are hoisted over the side of the ship by a conventional ring (not shown). The external guide and landing plates 72A on the well conduit are welded to the internal guide lugs 72 in the receiver assembly sleeve 56. The well conduit and receiver assembly are then lowered in the water beneath the keel of the ship and maneuvered into an upright position to be supported by the guide cables The rotatable insert 104 the drill pipe seal housing is removed and the drill bit 35, underreamer 36, drill collars 37, and drill pipe 34 are coupled together and lowered through the circulating head 30, receiver assembly 31 and well conduit 32 until the bit nears the ocean bottom. The rotatable insert 104 is then slipped on over the upper end of the drill pipe and locked into the drill pipe seal housing 90 by the locking pins 123. The Kelly joint 22 is then coupled to the upper end of the drill pipe and the drill bit is rotated by power supplied to the rotary table 25. Drilling fluid or sea water is pumped down the drill string to wash cuttings out of the well as drilling proceeds. The well is drilled to a depth equal to the length of the well conduit plus an additional amount to allow for sloughing of formation from the wall of the well. After the required depth is reached, rotation of the drill pipe is stopped and the drill pipe is raised slightly off the bottom of the well as shown in Fig. 1. Hydraulic pressure is applied to the well conduit seal 76 so that the circulating head is sealed to the well conduit 32. The guide lines 33 are then lowered to allow the well conduit to slide down over the drill pipe and into the well, as shown in Fig. 2. With the Kelly valve 23 closed, drilling fluid or sea water is pumped into the drilling mud return line (which is temporarily connected to the pump discharge) and out the lower end of the well conduit 32 as it is lowered to prevent drill cuttings from being forced up into the well conduit and possibly sticking the drill pipe 33 to the well conduit 32. The weight of the well conduit and circulating head is suflicient to overcome the friction between the drill pipe and the drill pipe seal 136. The well conduit may then either be cemented or held in the position shown in Fig. 2 until the formation has had suflicient time to settle around the well conduit and anchor it firmly in place.

Pressure is then released from the well conduit seal housing 76 and the drill pipe, underreamer and drill bit are raised. The drill bit engages the internal cushion ring 119 in the drill pipe seal housing 90 and raises the circulating head 30 to the dotted line position shown in Fig. 2. One of the guide lines extends forward under the keel of the vessel, over a supporting pulley carried by a forward bridle 161 slung under the forward part of the vessel. A weight 162 is attached to the free end of the guide line and hangs in the water-to maintain a constant tension on the guide line. A similar weight 153 is hung on the freeend of the other cable which extends rearwardly under the keel of the vessel and is run through a supporting pulley 164 carried by a rear bridle Ids-slung under the rear portion of the vessel.

33 directly under the cellar.

' duit.

The drill bit and underrean es combination may then be replacedhy a conventignaldrill bit and drilling may the be Q T T B.. l o. the eq red, dept as described in ctr-pe d n apn i t o i Serial Num e 8,214, filed.

' N mber; 1 .5

' I si d dur n he dr l ng o t e e l p o to ti he llccad 21a ea ng. uni s m ar to that of. thev well conduit seal76 can be usedto replace the drill pipe Seal 136 or'be mounted jonthe upperend of the drill pipe seal to provide means for gripping the drill pipe 34 with adjustable pressure, This type, of arrangement has the advantage of rigidlyholding and aligninglthe circulating head 35), receiver assembly 31. and well conduit 32 around the drillpipe as the well conduit is lowered into the well: Figs, 8 and 9 -illust rate;an alternate method for positioninga well conduit; 179 in an, underwater well 171. The upper portion of thewellconduit is rotatably disposed through a sleeve 172; and the-upper end of the well conduitextends abovethe sleeve.v A pair of; opposed and outwardly-extendingguide. post arms 173 are attached to the sleeve. Aseparatmiupright guide post 174 is attached to the outer end ofeach guidepost arm. The lower end ofe'acb guide post projects downwardly and outwardly .past its respective guide 'arm to form an anchoring spike 175; A separate, upwardly extending guide line176-is attached to the, upper end of each guide post.

An, annular lower bearing race 177' is attached to the the lower end ofa drill pipe 181 which extendsto. the

surface of the. waterto be powered by the drilling rig on V the floating vessel asdescribed for; the arrangement in Figs, 1 through 6. A; plurality of. conventional holddown anchors 18-2, e.g. ofthe Guiberson type, are provided in the portion, of the drill pipe Within the well'conduit, An anchor of this type is, illustrated in the Composite Catalog of ;O il Field and- Pipe Line Equipment, twentieth edition, 1 954,-55,, ,page 1940. -A plurality of laterally displaceable plugs 183 in; each hold-down anchor are actuatedby the hydraulic pressure of the drilling fluid within thedrill pipe and are iorced out against the interior of the well conduit to the drill pipe, An in erted swab cup lfi i is provided around the drill pipe near the lowerend ofthewellconduit, to seal the annular space between the. drill} pipe and; the well conduit, Thus the fluid pumped out ofithe drill bit is forced to return up the annularspace between the well conduit and the wellwall; to avoidthe possibility of'drill cutting s being c rried nt th qndu t ter nrand k n the drill pipe Within the wellconduin The well is drilled and the well conduit 1 70v positioned hin t e llls multaae uslv s fo w T e d l p p .14 r tatedb the dr ll a; g, ausi g e dn'llrbit and underrearner 186 t'o -drill a well. The hold-down anchors ili cause thewell conduittq rotate and move down with the drill-pipe During the rotation of the drill pipe, the; guide lines 176, extend upwardly and outwardly and are held. in; aspread-position to avoid fouling with the drill pipeas-it isrotated; This ,aids the anchoring spikes 1751:- preventrotation of; the guide post arms as the well is drilled; After the. required welldepth-is reached, the hydraulic pressure within the drill pipe isreleased, thus releasing-the hold-downi-anchors 182 from the wellcon- 'The retractable blades 185 .on the underreamer alsomove in; when. thehydraulic pressure is, released.

shown; in'dottedlines in I V, A V

Underreamers: of this type-,areawellrknown in the; drilling industry, as for example Baker model DT rotary hydran 1ic expansion wall scraper described, in the Composite Catalog of Oil Field and, Pipe Line Equipment, twentieth l edition, 195455, pages 5235527 The well conduit 170 may: be cemented in place or'the formation may be ale lowed to settle around the well conduit.

i be modified so the well conduit is rigidly connected to the sleeve guide, post arms 173 and guide posts174, the rotational feature being omitted, and the well conduit set in a. manner similar to that described in Figs. 8 and 9. Even with the anchors 175. in the groundand the well conduit rigidly connected to the: guide, post arms, the as.- sembly will rotate because the first few feet of ocean bottom is generally relatively soft. The casing is carried: downwardly with the drill pipe, until the anchors are in the ground firm enough toprevent further rotation, thus, establishing a firm footing for the upper end oi the well conduit. With such an arrangement theguide lines 176; are temporarily secured to the dirll pipe (or to the 'well conduit initially if the length of the conduit exceeds the water depth) above the water level and are allowed to rotate with the drill pipe. The guide, lines. may be secured to the well conduit oridrill, pipe in several ways,

the simplestbeing merely totie the lines to the conduitv or drill pipe with a rope 188. As the Well is drilledand the CQnduit 170 and drillpipe 181 move down, the guide lines if7dareintermittently disconnected and re-secured at a higher point to rotate with the drill pipe. 7 Thus, the guide lines rotate with the drill pipe and wellconduit, and donotbecome tangled, as would happen if-their upper ends Were held in a fixed location on the floating vessel, The underreamer may also beomitted, thelower end of the well conduit being serratedasshown at 186 (Fig. 8) so that it aids the drill bit in cutting a well of diameter large enough to accommodate the well conduit. After the well is drilled to the proper. depth, the well conduit may be anchored in place With cement187, or the formation may be allowed to settle around the well conduit. The guide linesare'released from the drill pipe and secured to supporting pulleys as described for Fig. 2. The hold-down anchors 182 are released and the, drill pipe withdrawn from the well conduit 170.

I claim:

1; The method of setting pipe in a formation, underlying at body of water comprising locating a floating vessel overthe formation, anchoring the vessel with elongated and laterally flexibleanchoring means in tension to permit limited horizontal and vertical movement of the vessel by the elements while anchored; supporting a drill string from the vessel extending through the water to the formation and carrying drilling means for forming a hole of larger diameter: than the.pipe,lowering the drill string from the vessel into contact with the formation, form ing in the formation with the drilling means a hole larger in diameter than the pipe, pumping fluid down through the drill string to cause fluidto flow up the annulus between the drill stringand the wall of the hole, suspending the.

pipe in tension around the drill string, lowering the pipe in the hole and affixing" at least aportion of theouter wall of the pipe: to thefOrmation while maintainingla flexible connection between, the: floating vessel ,and the pipein thesholejtolpermit:lateral displacementpf-thevessel; withlh'e. Pipe in,the-;h0le.. i

I 2,; Themethod according to claim lin which thefluid m nt ined lathe holeswhilelqw ri g he :P PP is rillin mud. g V l 3. The method according to claim 1 which includes leaving the drill string in the hole while the pipe is further lowered, and'pumping fluid down the drill string to maintain a flow of fluid up the annulus between the drill string and the ,wall of the hole while the pipe is lowered. I I

4. The method of setting pipe in a formation underlying a body of water comprising-locating a floating vessel over the formation, anchoring the vessel with elongated and laterally flexible anchoring means in tension to permit limited horizontal and vertical movement of the vessel by the elements while anchored, supporting a drill string from the vessel extending through the water to the formation and carrying drilling means for forming a hole of larger diameter than the pipe, lowering the drill string from the vessel into contact with the formation, forming in the formation with the drilling means a hole larger in diameter than the pipe, pumping fluid down through the drill string to cause fluid to flow up the annulus between the drill string and the wall of the hole, suspending the pipe in tension around the drill string, lowering the pipe in tension around the drill string while maintaining the drill string in the hole, guiding the lower portion of the pipe into the hole with the drill string, further lowering the pipe into the hole while maintaining the hole substantially full of fluid to provide lubrication between the pipe and the wall of the hole while the pipe is being lowered, limiting the downward movement of the pipe in the hole and affixing at least a portion of the outer wall of the pipe to the formation while maintaining a flexible connection between the floating vessel and the pipe in the hole to permit lateral displacement of the vessel with the pipe in the hole, thereafter advancing the drill string through the pipe, and drilling additional hole with the drill string below the lower end of the pipe.

5. The method according to claim 4 in which the pipe is anchored in the hole by pumping a fluidized cement into the annulus between the pipe and the wall of the hole.

6. The method of setting pipe in a formation underlying a body of water comprising locating a floating vessel over the formation, anchoring the vessel with elongated and laterally flexible anchoring means in tension to permit limited horizontal and vertical movement of the vessel by the elements while anchored, suspending the pipe in tension beneath the vessel, supporting a drill string from the vessel extending throughthe water to the formation and carrying drilling means for forming a hole of larger diameter than the pipe, lowering the drill string from the vessel through the suspended pipe into contact with the formation, forming in the formation with the drilling means a hole larger in diameter than the pipe, pumping fluid down through the drill string to cause fluid to flow up the annulus between the drill string and the wall of the hole, lowering the pipe in tension around the drill string while maintaining the drill string in the hole, guiding the lower portion of the pipe into the hole with the drill string, further lowering the pipe into the hole while maintaining the hole substantially full of fluid to provide lubrication between the pipe and the wall of the hole while the pipe is being lowered, and limiting the downward movement of the pipe in the hole and aflixing at least a portion of the outer wall of the pipe to the formation while maintaining a flexible connection between the floating vessel and the pipe in the hole to permit lateral displacement of the vessel with the pipe in the hole.

7. The method of setting pipe in a formation underlying a body of water comprising locating a floating vessel over the formation, anchoring the vessel with elongated and laterally flexible anchoring means in tension to permit limited horizontal and vertical movement of the vessel by the elements while anchored, suspending the pipe in tension beneath the vessel with a flexible line, lowering a drill string from the vessel through the pipe angstahole larger in diameter than the pipe, pumping fluid down through the drill string to cause fluid to flow up the annulus between the drill string and the, wall of the hole, lowering the pipe in tension around the drill string by paying out the flexible line while maintaining the drill string in the hole, guiding the lower portion of the pipe into the hole with the drill string, further lowering the pipe into the hole while maintaining the hole substantially full of fluid to provide lubrication between the pipe and the wall of the hole while the pipe is being lowered, and limiting the downward movement of the pipe in the hole and affixing at least a portion of the outer wall of the pipe to the formation, while maintaining the flexible line between the floating vessel and the pipe in the hole topermit lateral displacement of the vessel with the pipe in the hole.

8. The method of setting pipe in a formation underlying a body of water comprising locating a floating vessel over the formation, anchoring the vessel with elongated and laterally flexible anchoring means in tension to permit limited horizontal and vertical movement of the vessel by the elements while anchored, suspending the pipe in tension from and beneath the vessel, lowering a drill string from the vessel through the pipe to contact the formation, the drill string carrying drilling means for forming a hole of larger diameter than the pipe, forming in the formation with the drilling means a hole larger in diameter than the pipe, pumping fluid down through the drill string to cause fluid to flow up the annulus between the drill string and the wall of the hole, suspending the pipe in tension around the drill string, lowering the pipe in tension around the drill string while maintaining the drill string in the hole, guiding the lower portion of the pipe into the hole with the. drill string, further lowering the pipe into the hole while maintaining the hole substantially full of fluid to provide lubrication be tween the pipe and the wall of the hole while the pipe is being lowered, and limiting the downward movement of the pipe in the hole and aflixing at least a portion of the outer wall of the pipe to the formation while maintaining a flexible connection between the floating vessel and the pipe in the hole to permit lateral displacement of the vessel with the pipe in the hole, said aflixing of at least a portion of the outer wall of the pipe to the formation being accomplished by placing the lower end of the drill string adjacent the lower end of the pipe and pumping cement through the drill string to flow upwardly in the annulus between the pipe and the wall of the hole and allowing the cement to set.

9. The method of setting pipe in a formation underlying a body of water comprising locating a floating vessel over the formation, anchoring the vessel with elongated and laterally flexible anchoring means in tension to permit limited horizontal and vertical movement of the vessel by the elements while anchored, supporting a drill string from the vessel extending through the water to the formation and carrying drilling means for forming a hole of larger diameter than the pipe, lowering the drill string from the vessel into contact with the formation, forming in the formation with the drilling means a hole larger in diameter than the pipe, pumping fluid down through the drill string to cause fluid to flow up the annulus between the drill string and the wall of the hole, suspending the pipe in tension around the drill string with the lower end of the pipe spaced above the formation, lowering the pipe in tension around the drill string while maintaining the drill string in the hole, guiding the lower portion of the pipe into the hole with the drill string, further lowering the pipe into the hole while maintaining the hole substantially full of fluid to provide lubrication between the pipe and the wall of the hole while the pipe is being lowered, and limiting the down-

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