US2512783A - Marine drilling - Google Patents

Description

' Filed May 4, 194e s sheets-sheet 1 June 27, 1950 A. J. TUCKER 2,512,783

MARINE DRILLING FIG. 2

.47' 7' ORNE Y June 27, 1950 A. J. TUCKER 2,512,783

MARINE DRILLING Filed May 4, 1946 5 Sheets-Sheet 2 ausw/v5.1 72,6552 52 A INVENTOR.

5 BY Fls @MQ 3 oo 7, 2 l 5, 2

A. J. TUCKER MARINE DRILLING.

June 27, 1950 5 Sheets-Sheet 5 Filed May 4, 1946 AUGUST/Aff .z 7765542 INVENTOR.

FIG. 4

ATTORNEY Patented June 27, 1950 D ST ATENT OFFICE MARINE DRILLING Augustine J. Tucker, Houston, Tex.

Application May 4, 1946, Serial No. 667,290 l Claims.

solid platform, either on piling or on submergible barges or caissons, upon which the conventional drilling derrick and drilling machinery maybe mounted and drilling conducted therefrom in the usual manner.`

Such methods have been successful and reasonably economical when confined to drilling in,

relatively shallow water areas. However, since the depth of the Water puts a physically practical as well as an economically practical limit upon the driving of piles or the construction and operation of a suitably sized submergible barge, the practical maximum depth for these types of operation has been found to be of the order of perhaps 50 to 75 feet. Furthermore, unless rea- (Cl. Z55-2) sonably well protected from excessive wind and 4 wave conditions, drilling by these methods, even in shallow water, is attended by considerable are quite different than those used heretofore in drilling through shallow water.

In conventional drilling, whether practiced on dry land or through shallow water, using the submerged barge or piling arrangements referred to, a relatively rigid connectionmust b e maintained at all times between the well and the ,drilling equipment. rIhe surface casing, for

example, through which the drilling operations are conducted, forms such a connection. The drill stem, in the case of rotary drilling, is another part of such a connection. The result of this conventional arrangement that substantally no relative lateral movement may be permitted between the well and the surface equipment. It is for this reason that conventional marine drilling `techniques require a drilling platform which is rigidly anchored'to, and supported by, Vthe land underneath the water.

It seem obvious, therefore, that when the scene of drilling is shifted to the open ocean inareas where the water depths are of the order of sev-,

eral hundred feet, not only is it practically unfeasible to construct supporting structures which will extend to the bottom at such depths, but also the problem of anchoring such a structure,

with sufficient rigidity to withstand the heavy i wave and wind conditions normally present in the open ocean, becomes well nigh insurmountable.

Moreover, even if it were possible by existing methods to establish fixed platformsin the open ocean and to drill wells there, such structures, if left in place after the .well is completed, since they extend to the surface, would constitute serious hazards to ocean navigation which could be a matter of considerable concern to ship operators. If it were possible to remove the platform structure, the well head would remain so near vthe surface that it would likewise present an objectionable navigational hazard.

Accordingly, a principal object of this invention is to provide a methodv and apparatus for successfully drilling wells through deep water.

Generally speaking, the method of, this inventionfor accomplishment of the aforesaid principal objectY contemplates employment of a floating platform on the water surface for supporting the drilling equipment, a well head, through which the drilling operations are conducted, but

which is submerged at a substantial depthbelow the water surface, and generally 'flexible drilling and other operating connections between the floating platform and the submerged well head.

The iioating platform may be any suitable form of ship or vessel on which the drilling equipment mounted. The submerged well head is .of a novel form which includes a working vplatform adapted to be attachedtothe top of the well casing but atv sulcient depth below y the water surface, so as not to constitute a navigational hazard and tobe unaffected by surface" wind and wave action. The flexible drilling con- `areas through substantial water depths.

Other objects and advantages of this invention will be readily apparent from the following detailed description. when read in conjunction with the accompanying drawings which illustrate useful embodiments in accordance with this in- 5 vention.

In the drawings:

Fig. 1 is a plan view of the layout of the mooring connections forthe operating vessel;

Fig. 2 is a side elevation showing theI general arrangement of the well head, surface Vessel and mooring connections in relation to the Water surface and underlying land;

Eig. 3 illustrates the general assembly ofthe'- surface vessel, well head, well and drilling. eduip-` 15 ment, in accordance with this invention; and

Fig. 4 is a vertical, largely sectionalixniew'f'of the: A well head which shows the significant details.. thereof.

Referring to the drawings, Figs. l and 2 in pal:- ticular, a number of heavy mooringbuoys ;I0',ar ranged'in Va .circle on-the water surface, are an'- i chored'to 'the' land Vbottom byv means "of 'anchors II, preferably of themushroomtype, being connected thereto b y chains I2, the'lengths of which are preferablyabout %v4 greater than Ithedepth of the water in which the buoys are moored.` The number of buoysmay be varied, six beingshownmby `way of example. Similarly the diameter of the circle Aon which the buoys'; are AI hoored1ma-y:been varied and'is largely dependent upon various conditionstobe faced, such as the depth of -thewater, the'size of the vessel employed inthedrilling operations, and wind and Waveconditions generally prevalent in theareas where drilling 35 is tobe conducted. An operatingvesselr, with; its; bow generally centered: in theA mooring circle; is suitably moored fore and :aft to, the circlev of buoys by means of cables I4, insucha manner as to reduce to a minimum the ,degree of yaw,. 'iil particularly, and .to thereby holdpthe bow Yof the vessel as nearly ,.centrallyppositioned Within the circle lof buoysas possible. It will'abe obvious. that the' other. motions commonly affecting avessel in the open seat Will not be'materially -altered 11. or affected 4by, the type of mooring; since it will be. clear that pitching, rolling, and. .vertical rise and, fall,of theluesselwill bewery little aiected bythe. mooringdescribed While it would be.de' sirableif allsuchmotionsrcould be eliminated .or ,.50 greatlyreduced. this is deemed to be practically.. impossible of accomplishment and is not an impedment toachievingtheobjects of thisinven.- tion.,

Referring particularly to Fig.' 2, where the un- 5, deryzater.. mooring connections, `are best illus-g trated, a well headA designated generallmbythe numeral I5.is mooredinthecenter .of .the circle formed ,by 1b110ys maand. submerged .a suitable.. depth below the Y,surfacem Cables. |6 connect .the G0 Wel-1,. head ,to buoys .,I .and to Aanchor chains I2-..1 Arrangement is made,when.,dri1ling..of..the well isompletedto release .each ofthe combined ,connectionsfor-med bylcables. I6. and .chain.l2 from. theinattachmenttothe .buoys.` lIIL. so thai-...thesefr combinations will. form drectmoorings from anchors I I .to thewell Ihead.. thageneral. posi-tionrof this connection being shoWnatJB'. l When thus-. mooredto the .buoys Il), wellhead I5 will begenera1ly alignedwiththebow of.lvessel, |3 fromjo whichrdrilling, operations ...are conducted, as will be describedhereinafter. Although the vessel will necessarily undergoyarious degrees ,of motion,A under the. faction. of wind and-.Wave while the well head will be relatively unaiected.` the moor- 75 tal 4 ing arrangement described will keep the lateral movements of the bow of vessel I3 relative to the well head at a minimum.

Well head I5 (Fig. 4) comprises upper and lower otation chambers I'I and I8 respectively, which are vertically spaced apart and rigidly connected together by means of cross braces I 9. These otation chambers I'I and I8 are equipped with conventional control gear4 (not shown) for filling and emptying thechambers in order to control the buoyancy and thereby the depth of submergence of the well head. The arrangement of the otation chambers is so designed, that operationof the control gear will cause the well -head to-float. in.an upright position while submerged at any desired suitable depth. Mooring lugs Ia arefattached to upper flotation compartment.,I.`I .for connection thereto of mooring cables Upper dotation kchamber I'I ,is provided in the top thereof with a large ...funnel-shaped mouth 20which connects vto a large diameter tube '2|' extending entirely through the center @f both upper. and lower .flotationchambers A section of vtube 2 I between the two chambers may be cut out .t0 provide' access to the interior of the tube H and...to Y. th'e, equipment passing therethrough; For convenience, tube 2'I may be'composed of two axially alignedspaced apart sections as illustrated particularly in Fig.' 4. Thetop of chamber IB is providedwith an enclosing railing 22 and serves .as al working platform for divers in conducting certain .operationsto be described. The

upper.end .of the, -section of. tube. 2| passing through j,.lower.- chamber I 8 Vis provided with any suitableiormof .slipbowl `il'for the reception of pipe .grippingslipslil The upper section of tube ZI passingthroughlupper. chamber I l is equipped Y with yerticallyA spaced setsof spring controlled centering pawlsV 2 5..which are employed to center and .to `guide ..pipe such. as casing 26,. 'which is passed through,the,tube. A similark set of centeringspawls'` 2l `are.disposed..;1;1ear ther lower end. of the lower section of tube 2| passing through lower chamber. l I 8.1 Slips I24 and ,slipbowl 23 'cooperateswith pawls 2 .1forcentering the pipe sectionspassingl through .the lower section of tube 2 I Y,and forV aligning.. them lwith the. pipe Asections passing-.through thefuppersectonof tube 2I.

The lower end of tube 2|,.whichextends below chamber. I.8is provided with a collar 28 adapted for .attachment.thereto of a pilot tube29 which is of a. lengthsuicientto extend well into the land bottom from the ,lower end, of thewell head.

Pilot tube 29 yacts as a stabilizing anchor for the Well Ahead-as Wellas a guidecasing, through which allririlling .operations areconducted.

The-,.above ,describedgequipment is assembled and.arrangedin preparation. for. Vthe drillingioperationsI f-proper, in the. following manner: The

mooring. buoys-V I 0 are i anchored, as .described above, in .a circle.- Thediameter. of which may be,.forexample, y1200feet. ,Thewell head is then .towed Ainto the center, of 'themooring circle,

and. with,cables I6 .attaching it to the.buoys, the

controlsfon V,therflotation chambers are operated to cause .the .well head `to attain-.an upright position...while .,being, submergedl to .the desired depth,... This depth is preferably on. the order. of about 100 feet, as ,this is a depth which is sumciently shallowso thatdivers may work reasonably, comf ortably .en the wellhead and which is at the same time, wellbelow a depth at which the ,well head will .be aiected ,by surfaceA wind and wave conditions and out of theway of any asians ordinary surface trafc. fWh'en the well head' has attained the desired submerged position, in the center of the mooring circle, vessel I3 is'then moored to buoys I so that its bow is substantially centered in the mooring circle rand therefore, in general vertical alignment with the well head. As indicated above, exactitude of alignment is unnecessary, it being one of the advantages of this invention that such exact alignment need not be maintained.

With the vessel and well head in position as noted above, sections of pilottube 29 arev lowered from the vessel through mouth 20 of the well head and as the sectionsv pass downwardly through tube 2l, they are made up by divers working `on the well head until the pilot tube attains a length suicient to reach from' the bottom of the well head to the underlying land bottom. Enough additional sections are added to the pilot tube to allow its `lower end to sink as far as it is capable, by its own weight, into the ocean bottom. When this point is attained, the upper end of pilot tube 29 is welded to collar 28 and the well head is thus provided with a solid connection to the ocean bottom and which cooperates with the moorings to buoys I l) to hold the well head firmly in place for the conduct therethrough of the subsequent operations.

With the well headI in position and stabilized, as described, drilling operations may be begun and such operations and the equipment employed therefor will now be described.

A hollow buoy 30,'termed the drilling buoy,

yis moored to the bow of vessel I3 above the well head. Buoy 30 is shown in Fig. 3 outside the bow of the vessel, chiefly for purposes of clearer illustration. vIn practice this buoy will normally be positioned inside a well within the bow of the vessel, as indicated in Figs. 1 and 2, where it will be better protected against Wave and wind conditions and more accessible tothe operating crew on board the vessel.

The drilling string comprises a drill bit 3|, of generally conventional construction, which is attached to any suitable form of in-head engine 32, which may be of turbine, rotary or reciprocating type, above which is'connected a stabilizing cylinder 33 of suitable length, for example, 50 feet, to guide the bit in the drilling of a straight hole. Drill bit 3|, engine32, and stabilizing cylinder 33 comprise whatmay be termed the drilling head. Connected to the in-head engine 32, through stabilizing cylinder 33, is a `ilexible drill pipe 34 which extends upwardly through pilot casing 29, well head I5 and drilling buoy 3l) onto the deck or into the hold offvessel' I3, where vit is coiled down .and connected toe/a slush pump 35. This iiexible` drill pipe may be of any form suitable for the purposes .of this invention, and may conveniently be ofzthe same general type as was employed, Xforexample, inw

the flexible pipe lines laid throughtheeEnglish Channel during the war, beingadapted to withstand a bursting pressure of over 4000 pounds per square inch. Flexible drillpipe 34 is fed and guided over the bow of the Vessel by means of a series of sheaves and rollers, designated generally as a reeling mechanismY 36. ','A`cable 31 fed from a winch 38, is strung over conventional deck booms 39` and parallels the drill pipe, being connected to stabilizing cylindery 33r of the drilling head. Cable 31 is employed in connection, particularly with the raising of the drill pipe, as will be described hereinafter, A drilling mud tank 40, is provided within the hull of vessel I3 and is divided by a partition 4I to form a suction compartment 42 from which pump 35 takes suction on thek drilling 'fluid through a suction pipe Initial drilling operations for the purpose of setting surface Vcasing are begun by lowering the drilling head through drillingbuoy 30, well head I5 and pilot tube 29 to the bottom of the pilot tube. driving bit 3|, being discharged into the annular space between the wall of the well and the exterior of the drill pipe. During this initial operation the discharged drilling fluid and drill cuttings are washed upward to the mouth of thev well head which is open to the surrounding water, the fluid and cuttings being merely dissipated therein. When the well has reacheda suitable depth for the purpose of setting surface casing, an air supply 50 on board -vessel I3 is connected to the inbound end of llexible drill pipe 34 and isvemployed to blow the pipe clear of the drilling fluid. As the heavy drilling uid is blown from the drill pipe and is replaced by reeling mechanism is relatively small, and the need for the very heavy derricks and hoisting equipment normally required in rotary drilling is thereby avoided. In fact, cable 31 will serve ordinarily for applying an emergency pull to the drill string, in the event the drill head should stick in the hole. By providing suitable valving (not shown) in the drill head, the lower end of the drill pipe may be closed oil, `when the air has iinally displaced all the drilling fluid, such valving being of` afgenerally conventional form which is responsive to the change from liquid to gas passing therethrough to effect closing of the valve. With the drill pipe lled with` air,

it will, of course, have great buoyancy, so that, asl indicated, minimum effort is required to remove it from the well. In fact, control must be exercised in the rate of displacement of drilling uid by air, in order that the rate of withdrawal of the drill pipe at alltimes willbe undersuicient control to permit a steady and smooth operation of the reeling mechanism in coiling down the drill 'pipe as it comes aboard.

When the drill string has been withdrawn, as described, following the drilling of sufficient hole for vsetting the surface casing, the latter, designated by numeral 26,is lowered in sections from vessel I3, through the well head, the joints being made up by divers working on the well head plat:

form, and the string of casing, thus made up, isy

lowered through pilot tube 29 into the well and set on the bottom thereof. y casing 2B is'allowed to extend above the top of the well head and a master drilling gate valve 46 anda blow outpreventer 41, all of generally conventional construction, are connected to the topof casing 26'. A section of large diameter ilexible tube 48,'wl'iich is not required to withstand high pressures, and may, therefore, be of any suitable low pressure construction, is lowered through I drilling buoy 30 and its'lower end connected Vto blow out Apreventer 41. The upper end of ilexible tube 48 is provided with a Tftting' 49.v the Drilling is begun, the drilling uid, after The last section of nectedftheretowandl discharges` into mudbtank 1.40. a. Thecthenend1branch of yT ttingli; is providedw withaa stuffing box' 52L=throughiwhich drill pipe 34 and cable 31 are adapted to pass for further a* drillingxoperations. i Suitable hydraulic connec.

nected'stothe operatinghandles of *drilling masterV valve`=46 randblowout preventer 41-to enable controlling these devices fromfthei-drillingfbuoy thei eventrit isinecessany to close kthese devicesof;

Flexible tube 48;*-connectedas described,forms V a continuous, ,closed;;llexible connection-b etween .l

surface 'off the-.waterland the- -well head,l represented @by-:ther zupper.-,end fof V,casing r26, and this exiblefconneotion is utilizedfor allffurther drill-- ingqopera'tions; Surface casing. 26 may now be cemented ,sin thef` conventional ,-manner` through flexible tubef 48f=and upon- `completion of this'y op'- eration, drilling ofitheiwellfproper-is commenced t byfjeedingf` the: drill :pipe vthrough ilexible tube 48- and'casingl to thebottom, andpumping drilling iluidisfrom tank-AZ'to the drill head to drive `the l biirflThe drilling fluid exhausting from -the/drillf' ingsheadwillnow flowfbackto mudtank- 40, being conned.- inthe annular lspace between... the drill pipeiand casingflfand then VbetweenV the drill pipeand'y flexible v'tube Maand the conventional'- drillingnmud circulationwill'thus be maintainedw Wheni drilling iscompletedfto theefproducing 1 formation;:the inaly casing and tubing strings may bemunzgintdthewell.directlyfrom the surfacei if the .weather .is'suilicient-ly calm or lmay. be lowered,

ini-sections,:beingfzmadelup by-divers working at. thes'casing 4head-.f The usualfwell headtflow con-.--v

nectionslare then -made'to the topgof thecasing, andfithe'well drilledffin and placedfin `production in thegusualmannen Tof avoidi'bringing: any riinalfwell connectionsr:

to or near '.the'surface of thefwater,y the usual. productioniioutlet'sfat the :wellfhead (not shown) mayr befconnected by 5a' submarine pipe vlinev to "asuit-.e

able; shorestation:wheres theusual oil and `gas l..

separatorsrand storage tanks: mayl belocated.l g.

When .the wellis completed-fand placed in pro- Y duction,^f,cables;! 8 and anchorchainsfl 2 vmay-be releasedflfromibuoys'll and the anchors-connectedxiirectlyto' thewellrhead by cables I lasnotedA abcves: The". mooring buoys I0 may-then be re moyedf'ga'nd'uponrremoving yeesel-` iSv-iromthe'wellvicinityr: together with drilling buoy ,30,-I all pose.

siblzfnavigational hazards!A will bev removed.L A

small marking buoy may be left to markthelocai tion of the? lwell: or conventional l detection gearfor detecting underwater objects.may be em ployedi'.to"-locate theg well, 'whenever it. :maybe desireiitto return to itzf.'

Manly: alterations and. changes f mayfbe emade :in f.

the'fdetailsz'of ftheapparatus fand methods herein l described-@without vdeparting from l.the-scope .off thei appended claimsV but withinfthe-spirit' of this invention: .e

What claim:A andidesirei to securefbyLetters l; Marine drilling apparatus, ;I comprisingpzin l.

combination-a floating vesselfmoored jonzthe' surfaceof body ofWater, a ,chamberedw structure oflcbntrollable'. buoyancy 'submerged' beneath theA l vessel4 andi-between the; surface and 'the underlyingxrland` bottom; a vrigidiV vconduit connecting saidI structureV to Ysaid bottom; va large ldiameter .tubeaY composed oi:ritmo-axially4 alignedr spacecbapartl sections extending.l through L said; structurel andv Y communicatingfwith said conduit,. a submerged working.l p1atio1'm,disposed v'on said.y structure,.-:an.

opening' ein isaidfftube, adjacentfsaid platformflto merged-well. casing extending through ,said.tube .A and-saidconduit -a.exible. drilling-through con-v v duitextending-.betweenthe upper-.end of said ,casing-andsaid'tvesselfandmeansfor feeding va ilexible drill st emtfrom l saidvessel through .said l flexible drillingrthrough conduit.

2.. Marine-drilling. apparatus, comprising in combinationa` vessel aoaton-.a bodyof water,

--a plurality of mooringbuoysl arrangedgenerallyl.

circularly ',about:said. Ivessel and anchored to Vtheunderlying,landbottom;J mooring connections between saidfvesseland saidzbuoysa buoyant 4Workingzplatformsubmerged in said body of- Water below-saidtvessel and above the underlying f land bottom, mooringzconnections-extending from saidplatform 'to said fbuoys-l and` thence to said an` chord-:saidanooringconnections being releasable.

from saidxbuoys, a lar-ge diametertube composedVV of twola'xiallyf aligned spaced rapart sectionsv extending'througl'i-saidl platform, an enlarged con-.. duitfconnected-tosaidtube andextending to said landcbottom;.a4 submerged well casing extending. y

through-said tubeandfsaidfconduit, andafiexible drilling-'through f connection extending between said; vessel andsaidcasing;` f

3. Marinecdrilling.apparatus, .comprising Vin ed-to Vone end-:of said-tube and-extendinglto the land bottom,.a submerged well-.casing extending througlrsaid tube-A and -said conduit,l and a flexible-drilling-through .conduit extending between the'upperendfof vsaidhcasing; and said vessel;

4. Marine drilling. apparatus, comprising in combination,a iloati-ng-vessel mooredonthe sui'-,

face of a body ofwateryanunderwaterworking f.

plat-formisubmergedein :said: bodyof Awater `betweenfsa'id vessel'zand theyunderlyingland bottom, a conduit forming arigid connection betweensaid l platfor'mand saidi bottom", alarge diameter ftube= composed'of twoaxially'aligned spacedapart sections extending throughA said-platform communi catingwithfsaidconduit, a well casing extending throughaidf-:tubeland said conduit'into said;4 bottom;-.wellicontrol; ttingsr'mounted on the upperl end'of said 'casingpa :fiexible drilling-through Vcoriduiticonnected to 'saidcontrol fittings and extend-4 I ing'tosaidfvesselfandfmeanson saidl Vessel for feeding andiactuating a flexible d rill stem with a. f. drill' b'itf'mounted thereon through psaid 'flexible` connectionandsaidfcasingffor drilling a well.

5. Marinetidrilling:apparatus comprising in n combination, afiloatingvessel moored onfthe surfacel of Water;` a. buoyantwvorking: platform submergedcin said'fbodyaof ywaterfbelow said? vessel and? aboie .the i underlying land bottom; 'a large diametertuberrcomposed' of :two 'axially aligned spaced'eapartfy sections extending through'A said` platform, an@` enlarged rigidconduit connected' to 1onefendl of -fsaidfrtube and extending to' said landcbottoma submergedwell casing extending 'Y thrughlsaid.platforrntand said conduit Iinto said 'f.

bottom; a flexible f,drilling-through4 conduit conf necting the :upper end .of 'said casing to saidl vessel,1 fa flexible. hollow. drill stem-extending. from said,v yesselwthroughfsaid rflexible fconduit and said casing:tosaidfbottom,a duid actuated` engine-inheadedrillingrbit connectedto the lower end'of l Ysaid drillv stemgwandfmeans'on saidfvesseleto sup! ply actuating fluid through said hollow drill stem Number to said bit. 1,829,304 AUGUSTINE J. TUCKER. 1,998,803 2,013,070 REFERENCES CITED 5 2,171,672 The following references are of record in the 2187871 file of this patent:

UNITED STATES PATENTS Number Number Name Date 10 160,865

873,056 Lake Dec. 10, 1907 Name Date Schroeder Oct. 27, 1931 Collins Apr. 23, 1935 Sheridan Sept. 3, 1935 Plummer Sept. 5, 1939 Voorhees Jan. 23, 1940 FOREIGN PATENTS Country Date Great Britain Apr. 27, 1921

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