US2482616A - Installation for well control equipment - Google Patents

Description

p 1949- J. N. GREGORY ET AL 2,482,616

INSTALLATION FOR WELL CONTROL EQUIPMENT 7 Filed Nov. '7, 1945 s Sheets-Sheet 1 0 if: J):

\nven'l'orsZ James N. Greqorq Lewiz W. Elder Sept. 20, 1949- J. N. GREGORY ET AL INSTALLATION FOR WELL CONTROL EQUIPMENT 3 Sheets-Sheet 2 Filed Nov. 7, 1945 HqA lnvznTors'. James N. Greqorq Lzw'le W.-Eldzr. BL} Their Artornzq' P 1949. J. N. GREGORY ET AL. 2,482,616

INSTALLATION FOR WELL CONTROL EQUIPMENT Filed Nov. 7, 1945 3 shee'ts sheet 5 .\nvenToi-s'. James N Greqorq Lzwie W. Elder- Patented Sept. 20, 1949 INSTALLATION FOR CONTROL EQUIPMENT James N. Gregory, La Habra, and Lewie W. Elder,

Long Beach, Galifi,

.ment Company, San Francisco,

ration of Delaware assignors to Shell Develop- Calif., a corpo- Applica'tion November 7, 1945, Serial No. 627,114

(01. lot-i=1) 8 Glaims- This invention pertains to the art of drilling, cementing and completing oil and gas wells, and relates in particular to a method and apparatus for the installation of well control equipment in landing the outer or surface casing string.

Dee-p wells are commonly provided with a plurality of concentric casing strings extending to different depths from the surface. The outer casing is known as the surface string and extends usually to a depth prescribed by local regulations, such as about from 400 to roof) feet. A water string is arranged within the surface string concentrically therewith, and extends usually approximately to the top of the on hearing zone. One or more oil string-s may arranged within the water string and serve to bring the oil to the surface or to accommodate the tubing string through which the oil is produced.

Many methods and types of equipment have been heretofore developed for installing, cementing and landing these various casing strings, and for installing and connecting thereto suitable drilling riseryand casing head equipment atthe surface. These methods, however, generally involve certain drawbacks, such for example as a considerable loss of rig time attendant the necessity of waiting for the cement to set before continuing operations, a relatively poor control of the well during the cementing and landing operations, etc. 1

It is therefore an object of this invention to provide .a method and an apparatus whereby the surface casing maybe landed and cemented, and the control equipment at the surface may be installed and connected thereto immediately after the cementing operation, without waiting for the cement to .set, thereby cfllecting a saving of from four to sixteen hours of rig time.

It is also an object of this invention to pro-.- vide a method and an apparatus adapted to eliminate the necessity of welding or otherwise attaching the welding h ad to the surface casing after the latter has been placed in the borehole, thus greatly facilitating the landing and operations, obtaining a better control of the well, and effecting a further saving in time.

It isalso an object :of to provide a system adapted to assure a proper alignment of the landing head and of the surface casing with the center :or axis line .of the well as determined by the line of block t avel.

It is also an object of this invention to provide a system for the landing ofthe surface casing affording an adequate foundation for the cup:

I below.

'2 port of the surface and subsequent or inner strings of casing or tubing dependent thereon.

These and other objects of this invention will be understood from the following description of the installation of a surface string and well head control equipment according to the present invention, taken with reference to the attached drawings, wherein Figures 1 to 4 inclusive illustrate diagrammatically and partly in cross-section four consecutive steps in carrying out this installation, and Fig. 5 showsfanother embodiment of said installation.

Referring to the drawings, 1 shows a preferred cellar detail departure which is desirable to realize fully the advantages of the present invention. A'suitable cellar floor is formed as shown at 10 by pouring concrete with a form 11 placed in the center of the floor. The form H is made of any suitable material, such as wood, iron, cast-iron, steel, eta, having a square or circular shape anda cross-sectional area in a horizontal plane of about from 12 to 16 square feet. This form serves asa conductor box to receive the sub-conductor, as will be shown herein belcw. A cavity 42, from 4 to 20 feet deep is formed for the'sub-oonductor within and below the form 1 l.

After the cellar has been formed as illustrated in Fig. i, the derrick is erected, the derricksub-structure, generally indicated for example at M and I5 in Fig. 2, being positioned preparatory to installing the conductor. The derrick floor 14 is provided with the customary rotary table opening 16, substantially coaxial with the cavity 12 and the center line of the derrick, which normally coincides with the line of block travel. I

Referring to Fig. *2, the conductor pipe assembly or unit of the present invention consists of an elongated tubular conductor element having an upper portion 2% of a relatively larger diameter, such for example as inches, and a lower or su'bconductor portion 2| having a relatively smaller diameter such for example as 20 inches. The length oi the conductor element is regulated by desired spacing oi the landing head with regard to the rotary sill, which is necessary in order that the drilling riser and wellsfittings may subsequently be positioned at the proper level, as will be explained herein- In general, the length of the conductor element may vary fromabout 10 to about 20 feet, and that of the sub-tconductorelement from about '4 to about .20 feet.

and 2| are provided with connector means such as flange or plate members 23 and 25 respectively, formed integrally therewith, or permanently attached thereto by any desired means, such as welding, whereby the conductor and the sub-conductor may be .detachably joined together by means of bolts-21 passing through said flanges. A packing ring 24 should preferably be provided between the abutting faces of the flanges 23 and 25 to form a fluid-tight seal therebetween. Owing to the larger diameter of the conductor 28, the flange or plate connection between the members and 2| forms an internal annularshoulder 29 about the upper orifice of the sub-conductor 2|, which shoulder is used accordingto this invention for purposes to be described hereinbelow. The conductor 2E3 is open at its upper end 3 0, and is provided near said upper end with a radical flow outlet pipe connection 3 I, and near its lower end with a flushing pipe connection 33, which may have a considerably I smaller diameter than the pipe 3|. The conductor 20 is also provided near its upper end with outwardly extending support or bracket members 35, provided with suitable locking means for attachment to the derrick structure, as will be described hereinbelow.

In applying the method of the present invention, the form H of "Fig. 1 is removed, and the conductor 20 is bolted to the sub-conductor 2| to form a single unit, which is lowered into the cellar and is supported by means of brackets 35 from the sills or beams 31; forming part of the derrick structure.- The supporting brackets 35 are so spaced with regardgto the sub-conductor plate that when the conductor unit is suspended from thesills 3 1, saidplate 25 is substantially level with the cellar floor, and is thus correctly positioned to permit the subsequent installation of well fittings ;with respect thereto.

Before the conductor unit is finally affixed to the sills 31, its centeror axis line is aligned with the center line of the well to be drilled, as determined by the line of block travel. For purposes of this lateral adjustment, the brackets are provided with radially elongated slots for the bolts 39, attaching-the brackets 35 to the sills 31. With the conductor unit supported from the sills, cement or concrete is poured into the excavation l2, up to the plate 25 and substantially level with the floor ofthe cellar. After the cement has set, the plate 25, which may be circular or square in shape, and which has preferably a diameter larger than the conductor pipe 25, is firmly supported thereon.

Under certain conditions it may be desirable to provide a guide sleeve within the conductor 2% for the purpose of guiding drilling tools from the large diameter conductor 20 to the relatively smaller diameter sub-conductor 2| without stabbing at the annular shoulder 29. This guide sleeve comprises a tubular member 4|, having an internal diameter equal to that .of the subconductor, said tubularmember being flared at the top to an external diameter substantially equal, but slightly less than the internal diameter of the conductor 20, whereby the guide sleeve is adapted for a sliding fit within the conductor p pe. a

The guide sleeve MI-maybe provided near its lower end with guide elements such as wing guides shown at to centralize it within the conductor 253 and to align'it in register with the sub-conductor 2 Two ormore'lifting or link elements, such as cables or rods 41 are amxed in any suitable manner to the flaredlportion of the guide sleeve,

4 near its upper edge, being arranged diametrically opposite to each other and in close proximity to the inner wall .of the COI'ldllCtOl 20. These lifting rods may advantageously terminate in the form of a loop or eye 48, or similar suitable attachment device-at a level immediately above to open top of the conductor 20, and may be connected by a becket or bail 49. The becket 49 is prefer- 1 ably semi-circular in shape and, when in an inoperative position, as shown in the drawing, rests on the rim of the conductor without obstructing its opening, being however adapted to be engaged bya device such asa ,catline hook for the insertion or removal of the guide sleeve from the conductor. Upon-insertion, the guide sleeve rests with its lowerend on the annular shoulder 29.

With 'theconductor unit arranged as shown in the drawing, the hole for the surface casing may be drilled by guiding a drill string and bit (not shown) through the guide sleeve and sub-conductor and circulating the drilling fluid, in the usual manner, for-example, down the drill string and up through the annular space between the drill string and said sub-conductor and sleeve, and out through pipe connection 3|.

Before installing the surface casing string by means of the present apparatus, as shown in Fig. 3, the guide sleeve 40 isremoved from the conductor, the casing and the bore drilled therefor are measured for length, and a landing head 5!] is attached by welding or threading to the uppermost casing'joint. 58, which operation can conveniently be effected in a shop prior to running the unit thusformed; intothe borehole.

The surface string landing or casing head used in the system ofthe present invention comprises a bowl-shaped element 50, of an outside diameter somewhat larger than that of the surface casing, which head is adapted to be connected to the uppermost casing joint and is provided with an upper flange 53. Extending radially from the bowl 5!] are a plurality of spaced lugs 5|, welded or otherwise integrally attached to the casing head 50. Thedownwardly-directed faces 55 of the lugs 5| are shaped and dimensioned in such manner as to seat on the annular shoulder 29 and thus to provide for the support of the surface string and of all subsequent dependent strings from the plate25. If desired the lugs 5| may be attached to element 58 instead of 50.

In lowering the casing unit comprising the joint 58 of the surface string and the casing head 50 attached thereto, the flange 53 is first connected by bolts 59 to the lowerflange 5! of a lifting nipple 6U, andthe assembly is then lowered into the well until the lugs 5| come to rest on the annular shoulder 29. The lugs 5| are built of such an external diameter that they are slidably guided by the conductor 20 to land the surface casing 58 in axial alignment with the center line of the sub-conductor 2 I.

Should it be required, for some reason, to land the surface string in non-axial alignment-with the sub-conductor, the bolts 21 connecting the conductor 20 with the sub-conductor 2| may be removed prior to the landing, which will permit the casing head 50 and surface casing 58 to be shifted together with the conductor 20 in a horizontal plane with regard to the sub-conductor. Such operation may, for example, be necessary when the centering of the sub-conductor 2| is faulty, or when a drive pipe similar to the subconductor 2| had been-substituted therefor, it being impractical to align such drive-pipe with the well center. l w

After'the head .50 has :beenlanded on the plate 25, the surfacestring is cemented inplace by pumping .a cement charge down through the lifting nipple 60 and circulatingfluid out through the pipe connection 3|. Irthe, cement charge fills all the annular space between the surface string and the walls of the borehole and sub-conductor 2i excess cement may be flushed out through the lower pipe connection 33.

As soon as the cementing operation is com-.

sub-conductor, instead of the arrangement in- 2 3 and andbolts 21 shown in volving flanges Fig. 2, i'nvolve an arrangment comprising a flange forming a slip bowl 509 welded to, or otherwise permanently attached to the sub-conductor, into which the lower end of the conductor 200 is inserted to form a slip joint the r'ewith.

The guiding lugs 5H) of the surface string, which are shown attached to the upper casing joint instead of to the casing head as in Figs. 1-4, are provided with slanting or wedge-shaped extensions 5I l, which project downwards from the fiat portion of the lugs seating on the annular collar, and serve to center the surface casing string with regard to the sub-conductor, a function which is fulfilled in the embodiment of Figs. 1-4 by the slanting internal shoulder of the flange 23 attached to conductor Ell, as shown in Fig. 2. It is understood that the sparate features shown in Fig. 5 can be each used with the structure of Figs. 1-4, while the various features shown in Figs. 1-4 can in turn be used with the embodiment of Fig. 5.

We claim as our invention:

1. For use in a well derrick cellar structure, a tubular conductor unit for installing a surface casing string, said conductor unit comprising a lower tubular sub-conductor element of relatively smaller diameter adapted to be permanently embedded in a cement mixture immediately below the cellar floor, a removable upper conductor element of a diameter larger than that of the subconductor element adapted to extend in axial register with the sub-conductor element above the cellar floor, connector means for detachably affixing said elements to each other and anchoring them to the cellar floor, said connector means forming between said elements an annular shoulder transverse to the axis of said elements, support means exteriorly carried by the conductor element near the upper end thereof, and laterally adjustable means for detachably locking said support means to the derrick structure, whereby said conductor unit can be centered with regard to the derrick floor. 7

2. The apparatus of claim 1, comprising a tubular guide sleeve removably inserted in the conductor element, said guide sleeve having its lower end seated on the annular shoulder of the connector means, said lower end having radial dimensions substantially equal to those of the drilling through the surface slightly modified embodimento-t 6. subconductor element, the upper end of said guide sleeve being flared to form a funnel having radial dimensions substantially equal to those'of the conductor element; 7

3. The device of claim 2,'having radial centering means outwardly carried by said tubular guide sleeve, .said centering. means having a radial than the difference between length slightly less the internal radius of the-conductor element and the-outside radius of the tubular guide sleeve.

4. The device of claim 2,'having link means attachable to the flared portion' of :the guide sleeve near the outer edge thereof for lowering andlifting said guide sleeve within the conductor element.

5. The apparatus of claim 1, having'radially arranged pipe connection means through the Walls'of the conductor element.

6. In a wellinstallation comprising a derrick having an opening through the floor thereof, a cellar and a cavity in the cellar floor in substantial alignment with the derrick floor opening, the improvement comprising a conductor unit for in stalling a surface casing string, said unit com- .prising ;a tubular sub-conductor element of relaembedded in;

tively smaller diameter permanently a cement mixture in said cavity in the cellar floor, a removable upper conductor element, of a diameter larger than that of the sub-conductor element in. axial register with the sub-conductor element above the cellar floor, connector means detachably affixing the lower end of the conductor element to the upper end of the sub-conductor element, said connector means forming between said elements an annular shoulder transverse to the axis thereof, support means exteriorly carried by the conductor element near the upper end thereof, and laterally adjustable centering means detachably locking said support means to the derrick structure in adjustable alignment with said cavity in the cellar floor.

'7. In a well derrick cellar structure, in combination, a conductor unit comprising a lower tubular sub-conductor element of relatively smaller diameter permanently embedded in a cement mixture below the cellar floor, a removable upper conductor element of a diameter larger than that of the sub-conductor element in axial register with the sub-conductor element above the cellar floor, connector means detachably affixing said elements end to end to each other, said connector means being anchored to the cellar floor, said connector means forming between said elements an annular shoulder transverse to the axis of said elements, support means exteriorly carried by the conductor element near the upper end thereof, laterally adjustable centering means detachably locking said support means to the derrick structure, a surface casing unit extending through the conductor unit coaxially therewith, said casing unit comprising a casing string having an outside diameter smaller than the inside diameter of the sub-conductor element, a casing head connected in said string, said casing head having an outside diameter smaller than the in- 7 side diameter of the conductor element but larger than that of the sub-conductor element, and spaced radial lugs exteriorly carried by said casing unit below the casing head, said lugs seating on said annular collar of the connector means to support the casing unit thereon, the spaces between said lugs forming flow channel means for fluid circulation between the annular space around the casing string below said connector means and theannular space arounds the casing string above the connector means.

8; For use in a'well structure comprising a derrick having an opening through the floor thereof in substantial alignment with the well bore, a cellar under the'derri'ck floor anda cavity in the cellar floor substantially co-axial with the well bore, in combination, 'a conductor unit comprising a lower tubular sub-conductor element of relatively smaller diameter permanently embedded in a cement mixture in said cavity, a removable upper conductor element of a diameter larger tha'nthat of the sub-conductor element in axial register with the sub-conductor element above the cellar floor, connector means anchored to the cellar floor detachably'aifixing said elements to each other, said connector means forming between said elements an annular shoulder transverse to the axis of said elements,isupport means exteriorly carried by the conductor element near the upperend thereof, laterally adjustable centering means 'detachably locking said support means to the derrick, radial flow pipe connection means through the walls of the conductor elemerit, a surface casing unit extending into the well bore through the conductor unit co-axially therewith, said casing unit comprising a casing string having an outside diameter smaller than the inside diameter of the sub-conductor element, a casing head connected in said string having an 8 outside diameter smaller than the inside diameter of the conductor 'elementbut'larger than the inside diameter of the sub-conductor element, and spaced radial lugs exteriorly carried by the casing unit below the-casing head, said lugs seating on said annular-collar of the connector means to support the casing unitthereon, said lugs forming therebetween channel means for fluid circulation between saidlradial flow pipe connection means, the annular space around the casing string within the conductor element and the annular space around thecasingstring in the well bore below said conductor element.

' JAMES N. GREGORY.

i LEWIE W. ELDER.

,. REFERENCES CITED The followingreferences are of record in the file of this patent:

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