US2554276A - Blowout preventer - Google Patents

Description

May 22, 1951 A, L, STQNE 2,554,255

BLOWOUT PREVENTER 3 Sheets-Sheet 2 Filed July 24, 1948 (afa asv@ g/21o?? Mam, lNvENToR.

2. GW W17 ATTORN EY.

May 22, 1951 A, 1 STONE Bpowou'r PREVENTER Filed July 24, 1948 3 Sheets-Sheet 3 Patented May 22, 1951 BLOWOUT PRsvaNfrsa Albert L. Stone, Redondo Beach, Calif., assigner,

by mesne assignments, to Standard @il Development Company, Elizabeth, N. J., a. corporation of Delaware lApplication July 24, 1948, Serial No. 40,571

(Cl. Z55- 19) 9 Claims.

This invention relates to blowout prevention of oil and gas wells and pertains more particularly to means for sealing a Kelly rod against well pressure in order to control the axial outlet of such wells.

In the rotary drilling of boreholes into the subsurface formations for the production of oil and gas, a drill feeding mechanism, such as a Kelly rod, is rotated by an appropriate mechanism. The drill stem is axially connected with the drill feeding mechanism so that rotation of the drill feeding mechanism produces rotation of `the drill stem. The drill rotating mechanism must not only rotate the drill feeding mechanism, but must permit longitudinal movement of the drill feeding mechanism therethrough so as to permit lowering and raising of the drill stem in accomplishing .the drilling. The drill feeding mechanism may be a round Kelly rod of the type having longitudinal grooves on the outer surface thereof which are gripped by elements of a bushing mounted in the drill rotating mechanism for rotating the Kelly rod. In order to provide coinplete control of the well pressure, it is not only necessary to provide sealing means between the well casing and the drill stem but sealing means must also be provided between the well casing and the grooved Kelly rod. Various means have been employed for providing the seal between the well casing and the drill stem which have proven satisfactory in operation. When, however, a round Kelly rod having longitudinally extending grooves on its outer surface is employed, the sealing means ordinarily employed for sealing a drill stem cannot satisfactorily be used for sealing the Kelly rod inasmuch as that portion of the sealing means adjacent the grooves of the kelly will be deformed into these grooves. Deformation of the sealing means, as described above, prevents rotation of the round, grooved kelly when in operative relation with the sealing means.

An important object of this invention is to provide a seal between a round Kelly rod having longitudinally extending grooves in its outer surface and a sealing means mounted on the Well casing. A further object of my invention is to provide a sealing means having a small pressure subject area for a grooved, round kelly which will permit rotation of the kelly and at the same time permit longitudinal movement thereof. A further object is to provide a means for sealing a grooved, round kelly when employing a blowout preventer equipped withsealing means of conventional design.

Briefly, this invention concerns the provision of a member adapted to rotate with a grooved, round Kelly rod, the said member having vertically extending l'ingers, the inner surfaces of the fingers fitting slidably and sealably into the grooves of the kelly and the outer surfaces of the fingers cooperating with therouter surface of the kelly to define a cylindrical surface coinciding with the outer surface of the kelly. With this arrangement the conventional sealing means, such for example -`as rams, of a blowout preventer may be closed around the kelly adjacent the aforementioned fingers thus providing a positive seal so that no well fluid escapes from the well head past the kelly. Of course, with this arrangement, lthe Kelly bar may be rotated While in operative relation with the sealing means and therefore sealed against well pressure and may also be moved vertically While so sealed in accordance with the demands of the drilling operation. Another advantage of this arrangement is that the fingers which slidably and sealably fit the grooves yof the .kelly present a very small area which is exposed to the pressure exerted by the well fluid and, consequently, Aare subjected to a relatively low total pressure. Inasmuch as the total pressure is of a low .order of magnitude, the upward thrust produced by the fingers by reason of the pressure exerted by the Well fluid may easily and simply be absorbed by suitable means. This is a distinct advantage over the prior art devices designed for providing a seal around ra rotating and longitudinally movable kelly. For example, a round grooved kelly, such as I employ, having an overall diameter of 6 inches and provided with sie grooves having a radius of 974 inch and a depth in the kelly of approximately 5A; inch would require six fingers presenting a total area of approximately l sq. in. to the well iiuid.' Assuming a well pressure in the order of 2,000 lbs. per sq. in., the total pressure tending to force the fingers upwardly would be in the order of 2,1000 lbs. This small thrust can easily be taken care of by employing ngers of the proper strength and mounting means for the fingers of the proper design Without resorting to cumbersome arrangements which have been employed in the prior art devices for overcoming the tremendous upward thrusts involved.

Other objects and advantages of my invention will be apparent from the following description and the accompanying drawing wherein:

Fig. 1 is a vertical section through a grooved Kelly sealing mechanism in active sealing relation with a grooved kelly and the rams of a blowout preventer, embodying the features of the present invention;

Fig. 2 shows the section on the line II-II of Fig. 1;

Fig. 3 is a perspective view of a grooved Kelly sealing mechanism;

Fig. 4 is a section on the line IV-IV of Fig. 3;

Fig. 5 is a perspective view of another embodiment of a grooved Kelly sealing means;

Fig. 6 is a vertical section through another embodiment of a grooved Kelly sealing mechanism;

Fig. 7 is a View in elevation of a portion of the Kelly bushing shown in Fig. 6;

Fig. 8 is a side View in elevation of the bushing shown in Fig. 7;

Fig. 9 is a section on the line IX-IX of Fig. 6;

Fig. 10 is a section on the line X-X of Fig. 6;

Fig. 11 is a plan view of another embodiment of a grooved Kelly sealing mechanism together with a mounting means for same; and

Fig. 12 is a vertical section on the line XII-XII of Fig. 11.

` Referring first to Figs. 1 to 5, inclusive, of the drawing, a round Kelly bar IU having a plurality of longitudinally extending grooves I I is mounted for rotation about its axis in a Kelly drive bushing C, bushing C carrying therein circulating balls I3 which are adapted to fit into grooves II of Kelly bar I0 for transmitting thereto the rotary motion of rotary table I4 which carries bushing housing I4 thereon with Kelly drive bushing C mounted in said housing. Kelly drive bushing C is removably held in place within bushing housing III by means of retaining member I2. Kelly drive bushing C is also adapted to permit Kelly bar I@ to move longitudinally therethrough with ball bearings I3 in engaging contact with longitudinally extending grooves II. A detailed description of the structure and operation of Kelly drive bushing C and Kelly bar I0 may be found in my copending application Serial No. 66,772, filed December 22, 1948. For the purposes of this invention, it is suiiicient that Kelly drive bushing C transmit rotative motion to kelly IIJ while permitting longitudinal movement thereof. Kelly I0 is also shown as extending through a blowout preventer I5 and the upper portion of a wellhead I 6. In the drawing blowout preventer I5, mounted adjacent kelly I0 with its axis coinciding with the axis of the kelly, has been Shown diagrammatically as consisting of a housing I1 engaged with a wellhead I6, the said housing defining an annular recess I8 adapted to receive oppositely disposed rams I9 consisting of a deformable material, such as rubber, for providing a seal with the outside cylindrical surface of a tubular member when said rams are brought into operative contact with said surface by a suitable mechanism of conventional design, not shown. As will be noted in Fig. 2, rams I9 define an inner surface which is cylindrical in form when the said rams are brought into operative contact with a member having an outer cylindrical surface.

As will be noted from Fig. 1, grooves II extend to the upper extremity of kelly I0 and terminate at their lower ends in surface II, which surface is preferably normal to the surface of grooves II.

The Kelly groove sealing mechanism, perspectively shown in Fig. 3 and designated as assembly A, consists of a circular framework 2| defining a central passage 22 of sufficient diameter to permit passage of kelly I0 therethrough having vertically extending fingers 23 curcumference of central opening 22.

is firmly pressed into groove II.

arranged with the axes of said fingers on the The upper surface of circular framework 2I defines a plurality of threaded holes I. Fingers 23 are spaced cn the circumference of central passage 22 so as to coincide with longitudinally extending grooves II of Kelly rod I0. The inner surface 2li of fingers 23 are shaped to conform to the configuration of grooves I I. In the drawing inner surface 24 of ngers 23 is shown as arcuate in form to conform to the arcuate configuration of grooves II although it will be understood that grooves II may be of any desired configuration and that surface 24 of fingers 23 are to be of corresponding configuration. A thin coating of deformable material 25, such for example as rubber, covers surface 24 so as to provide a fluid-tight seal between surfaces 24 and the surface formed by grooves II when the fingers are in operative relation with the grooves. It will be understood, of course, that deformable material 25 may consist of any deformable material which will Provide a fluid-tight seal between surface 24 and the surface formed by groove II when finger 23 Outer surfaces 26 of fingers 23 must necessarily be arcuate, thc curvature being such that outer surfaces 26 cooperate with the outer surface of the kelly, when deformable material 25 is in sealing contact with groove Ii, to form a cylindrical surface. The surface formed by outer surface 2B of fingers 23 and the outer surface of kelly I0 must necessarily be cylindrical in form so that the said surface may be rotated while in sealing contact with surfaces 20 of rams I9. While the drawing shows six vertically extending fingers 23, it will be understood that the number of ngers 23 must necessarily correspond to the number of grooves II on the outer surface of the kelly.

In Fig. 3 assembly A is shown as consisting of a continuous circular framework 2I having vertically extending fingers 23 mounted thereon, the fingers and framework forming one integral part. Instead, however, of forming one integral part, assembly A may be constructed in segments as shown in Fig. 5. In Fig. 5 circular framework 2I is shown as consisting of three segments, to-wit, a, b. and c, although it will be understood that circular framework 2I may be divided into any number of desired Segments. Fig. 5 also shows fingers 23 mounted on circular framework 2l with the fingers equally divided between segments a, b and c. Each of segments a, b and c define a threaded hole in their upper surface adapted for receiving a threaded bolt or screw. As a matter of fact, the embodiment of assembly A shown in Fig. 5 is identical with the embodiment of assembly A shown in Fig. 3 except for the fact that circular framework is split into segments instead of appearing as a continuous ring. The modification shown in Fig. 5 is secured in place on the housing I1 of blowout preventer I5 similarly to the modifi'- cation shown in Fig. 3.

Longitudinal movement of the grooved .Kelly sealing mechanism is prevented by removably secured roller bearing 21 which is mounted on an outwardly extending ring portion of circular framework 2I and on housing I'I of blowout preventer I5. Bearing 21 is held in position by retaining ring 29 defining upper surface 29 which tapers downwardly and outwardly and by ring 2 which is secured to circular framework 2I by means of screws 3 which are adapted to -pass through ring 2 and to threadedly engage with .threaded :holes I .in .the .upper surface 4of circular framework 2l.. Bearing 27 permits assembly .A to rotate with kelly I .when the kelly is rotated .while rams I9 are in position for sealing the kelly.

.Locking ring 29 is heldin place by means of a lreleasable locking means designated as assembly B which includes a housing 3B secured to the housing I'I of .blowout preventer I5 by suitable meanssuch ascap screws 3 I. Housing .39 denes a passage, rectangular in shape, in which is slid ably arranged a movable Ycam member 32. The outer surface of cam member 32 is generally rectangular in shape which allows it to move slidably within :housing 39 while 1the outer end surface thereof defines 1a slanting or wedge surface 33. Cam member 32defines a central cylindrical cavity which is vadapted to carry piston 34 slidably therein. Piston 34 .is attached to `piston rod which, .in.turn, is secured to housing 30.

.A .packing .3,6 is mounted on piston 34 to preventfleakage between .the exterior surface thereof and `the .cylindrical -wall of cam member 32. Another packing 3'I is provided around ,piston rod 95 toprevent leakage Varound the piston rod. The portion of :the-cavity defined by 'a member 32 between said piston 34 and packing 3'! is designated as 38 While the portion of the cavity between piston 34 andthe end of member 32 delining wedge surface 33 is designated as 39. Piston rod 35 defines a central passage 40 extending longitudinally through said piston rod and communicating with cavity 39 and connected through conduit 4I to a suitable source of hydraulic pressure, not shown. Cam member 32 defines a side port 42 fluidly connecting with cavity 38 and connected through conduit 43 to a suitable source of hydraulic pressure, not shown.

It will be seen that by exerting pressure in cavity 39 while releasing pressure from cavity 38, cam member 32 may be pushed toward locking ring 29 to force wedge surface 33 of cam member .32 into contact with ytapered lsurface 29' of ring 29. With surface 29 and surface 33 in contact, the fluid pressure exerted against cam member 32 biases retaining ring 29 downwardly thus holding bearing 2'I and, in turn, assembly A in place. With assembly A so placed, rams I9 of blowout preventer I5 may be closed about kelly Ill and lingers 23 of assembly A to provide a fluidtight seal between rams I 9 and the kelly. While rams I9 are so closed, .kelly I El may be rotated therein and may simultaneously be .moved longitudinally.

By exerting pressure in-cavity 38 while releas- :3.

ing pressure in cavity 39, cam member .32 may .be pushed away 'from retaining ring .29 thereby disengaging surface 33 of cam 32 from surface .29 of retaining ring 29. With cam 32 in :the aforementioned retracted position, retaining ring 29 may 'be lifted from its position holding bearing 2 in place, bearing 21 may then be removed from its seat on outwardly extending ring 4portion 2S of circular frameworkzl and assembly A may be moved vertically along kelly II] with fingers 23 in'grooves II. In this manner assembly .A `may be moved upwardly on vkelly I9 to any desired or convenient point.

In the drawing two hold-down assemblies B are shown. It will be understood, of course, that the number of such assemblies employed is not critical and that one or more of such assemblies may be utilized with satisfactory results. Actually, I prefer to employ three such .assemblies radially vspaced with respect to r bearing .21 so as 6 to minimize the canting of said bearing in its seat. reduce the vtendency of bearing 21 to cant, but ordinarily it will be found unnecessary to employ more than threeof such assemblies.

It will be further understood that assembly B need not be hydraulically operated. As a matter of fact, any releasable latching means may be employed for holding ring29 in place and maybe either-hand operated or power operated, although I prefer to employ a hydraulically operated latching means for convenience in quickly inserting @or 4removing assembly A. When the sealing mechanismshown -in Figs. 1 and Bis employed for providing a seal .between Kelly rod IIJ -and rams .I9 of blowout preventer Il, assembly A shown in Fig. 3 is `inserted over the upper end of Kelly :rod IIJ with fingers ,23 pointing down- Wardly and .fitting slidably into grooves II. Bearing-2l is-fit into retaining ring 29 after which bearing 2l and ring 2-9 is passed over the upper end 4of ,kelly lil with surface 29' of retaining ring 29 yfacing upwardly. Ring l2 Ais then passed ,over theupper end of kelly Il), after which ring 2 is aiiixed to assembly `A by means of bolts 3 which are passed .through ports 3 and threadedly engaged in holes I `defined byfassembly A. In this manner .bearing 21 is clamped between-outwardly extending `portion 28 of assembly A and ring 2 with retaining ring 29 mounted on the outer periphery of bearing 2?. Assembly A, bearing 27, retaining ring .29, ring 2 and bolts 3, after being assembled in the .aforementioned manner, may then .be .moved along the kelly with fingers 23 in sliding contact with grooves II. Kelly rod I9 is then suspendedby a suitable means and the lower end inserted through -the central opening of rotary .table I4, blowout preventer I5 and wellhead I6 until .the `lower edge .of retaining ring 29abuts againsthousing I'I yof .blowout preventer .I5. Retaining ring Y29 may thenbe locked in place by cam 32 .of assembly B in the manner hereinbefore described. Bushing C may then be inserted over the Upper vend of kelly .IU and lowered into place in rotary table I4. With the vsealing mechanism inthe locked position -kelly bar I may be `rotated by means Yof rotary table I4 and bushing C and when so rotated, assembly A, ring 2, bolts .3 and the inner race vof bearing 21 will also rotate. Whenit is desired to seal kelly I 0 against well pressure, rams I9 of blowout preventer I5 are moved lto the closed position in contact `with kelly I0, thus pressing fingers 23 firmly within ,grooves Il. Inasmuch as the outer surface .29 of fingers 23 cooperate with the outer surface of kelly Ill to denea cylindrical surface in sealing contact Ywith rams I9, kelly I9 may be rotated and movedlongitudinally within rams I9, thus'preventing the Vescape of well fluid past the kelly.

When .kelly .bar Ill :is to be removed fromwellhead 1:6 and .blowoutrpreventer I5, as for example, when .-another section of drill pipe is to be added, cams 32 of assembly -B are retracted as hereinbeiore described vand kelly bar yI9 is raised until the `lower-ends of `fingers 23 abut against surface I.I. Continued raising of the kelly will consequently raise assembly A together with Yring 2, bearing 2l, retaining ring 29 and bolts 3 until such time -as the sealingmechanism abuts against the lower edge of Vbushing C. Continued raising of kelly .I9 will vthen vof course also lift bushing C fromitsseatin-rotary table I4. Kelly bar 3 may thenbe raised to a-sufiicient height to insert an additional section .of .drill pipe-after which Kelly Of course, a larger number would also bar I may be connected thereto. Kelly bar l0 may then be lowered until bushing C again assumes its seat in rotary table I4 and ring 29 abuts against housing l1 of blowout preventer l5, at which time cam 32 may be moved into the closed position for latching the sealing mechanism in position as hereinbefore described.

The modilication of assembly A shown in Fig. 5 is mounted on Kelly bar Il] adjacent blowout preventer l5 in a manner similar to that described in connection with the modification shown in Fig. 3. The only difference between the two mcdications is that in the case of modilication shown in Fig. 5 assembly A need not be slipped over the upper end of kelly i0 inasmuch as assembly A is split into segments a, b and c. Instead,l segments a, b and c may each be moved laterally into position on the outer surface of kelly i!) to form a circular framework around the kelly. After bringing segments a, b and c into position on the kelly, these segments are operatively joined with bearing 21, ring 2, bolts Sand ring 29 in a similar manner to the manner hereinbefore described for assembling these parts with assembly A shown in Fig. 3.

Figs. 6 to l0, inclusive, show another embodiment of the grooved Kelly sealing mechanism of my invention. In this embodiment, the vertically extending lingers adapted to slidably and sealably lit into the grooves of a grooved kelly are attached directly to the lower end of the Kelly bushing thereby permitting the rotation of the lingers with the kelly without the necessity of providing a bearing and hold-down means as shown in Fig. 1.

Referring to Figs. 6 to l0, inclusive, 50 designates a round Kelly bar having longitudinally extending grooves 5|. Grooves 5| terminate at their lower end in surface 52 which is normal to the surface formed by grooves 5|. Surface 52 is normal to the surface formed by groove 5| instead of being dished, as is normally the case, for a purpose which will hereinafter appear. Kelly 50 is shown arranged within blowout preventer 53 and casinghead 54 and mounted within the central passage 9 formed by Kelly drive bushing C. Kelly drive bushing C consists of housing 10 which is adapted to lit in the conventional manner into rotary table 1| so` as to rotate in cooperation with the rotary table and is remov- :'.1

ably secured to rotary table 1| by means of bolts 10. The inner walls of housing 1U are provided with key ways 12 adapted to receive bushing inserts 13. Inserts 13 are arranged within key ways 12 so that their inner surfaces 58 cooperate to form central passage 9 in bushing C. Inserts 13 are held against vertical movement with respect to housing 10 by means of housing cover 14 which is removably aflixed to housing 10, as by means of threads 15. Bushing inserts 13 deline ball bearing race 5S carrying circulating balls 51. Race 56 is so arranged that a portion of balls '51 partially project beyond the inner surface 58 of inserts 13, the projecting portion of balls 51 fitting into grooves 5| of Kelly rod 5U. Consequently, when rotary table 1| is rotated, Kelly drive bushing C also rotates thereby imparting rotation to Kelly rod by means of the engagement of balls 51 with grooves 5|. Kelly rod 59 is also free to move longitudinally through Kelly drive bushing C and when Kelly rod 50 is moved longitudinally, balls 51 circulate in ball race `56.

Mounted on the lower inner edge of each of bushing inserts 13 is a vertically extending finger 59. each linger being adapted to lit slidably and sealably in a groove 5| of kelly 50 as shown in Figs. 1'1, 8 and 9. It will be understood, however, that a sufficient number of lingers 59 must be affixed to the lower inner edge of inserts 13 to provide a finger for each groove 5| of kelly 5|) as shown in Fig. 10. Thus a suflicient number of inserts 13 must be provided in housing 1|)l to carry suliicient fingers for the aforementioned purpose even though the said inserts are not provided with a ball bearing race carrying ball bearings as shown in Figs. '7, 8 and 9. It will be further understood that the structure shown in Figs. '7, 8 and 9 for engaging and transmitting rotative movement to the kelly forms no part of this invention. As a matter of fact, any Kelly bushing which will transmit rotative movement to the kelly while permitting longitudinal movement of the kelly therethrough may be employed in accordance with the present invention. Fingers 59 are disposed on the circumference of central opening 9 of such a bushing at the lower end thereof so as to lit sealably and slidably in each of the grooves of the kelly. Fingers 59 are of suliicient length to extend along grooves 5| to at least a point below the lower edge 69 of rams `53 carried by blowout preventer 53.

The inner surface 6| of lingers 59 are shaped to conform to the configuration of grooves 5|. In the drawing inn-er surface 6| of lingers 59 is shown as arcuate in form to conform to the arcuate configuration of grooves 5|, although it will be understood that grooves 5| may be of any desired configuration and that surface 6| of lingers 59 is to be of corresponding configuration. A thin coating of deformable material 62, such for example as rubber, covers surface 6| so as to provide a fluid-tight seal between surface 6| and the surface formed by grooves 5| when lingers 59 are tightly pressed into said grooves. It will 1 be understood, of course, that deformable mate- 5| while still permitting Kelly rod 5i] to move longitudinally with respect to said lingers. Outer surfaces 63 of fingers 59 must necessarily be arcuate, the curvature being such that the outer surfaces 63 cooperate with the outer surface of the kelly to form a cylindrical surface when ngers 59 are in sealing slidable contact with grooves 5|. The surface formed by outer surfaces 63 of lingers 55 and the outer surface of kelly 55 must necessarily be cylindrical in form so that the said surface may be rotated in sealing contact with surface E4 of rams 53. The lower end surface of lingers 59 is normal to inner surface 6| of the lingers so that surface 65 can make contact with surface 52 at the lower end of grooves 5|. Fingers 59 are made to possess sufficient strength to support the weight of Kelly drive bushing C on abutment of surface 65 on surface 52.

When it is desired to seal kelly 59 against the passage of well liuid from casinghead 54, rams 53' are closed tightly around kelly 5U. rlhe pressure of rams 53 forces the deformable material 62 carried by the inner surface GI of lingers 59 into close contact with the surface defined by grooves 5| and also provides a fluid-tight seal around the surface delined by outer surface 63 of lingers 59 and the outer surface of kelly 5D. Thusly, the closing of rams 53 prevent the passage of well liuid from casinghead 64 inasmuch as an effective seal is provided between kelly 50 Y9L and blowout preventer 53. At times, such for example as when an additional string of drill pipe is to be added, it will be necessary t withdraw the kelly from the casinghead and the blowout preventer. During such an opera-tion, the Kelly drive bushing employed is conventionally permitted to remain on the Kelly bar and after the Kelly bar is disconnected from the drill pipe, the Kelly bar and the Kelly drive bushing are lifted from the hole. When such an operation is to be carried out with the embodiment shown in Figs. 6 to 10, inclusive, the Kelly bar itself is raised in the conventional manner, bolts 10', which removably secure bushing C" to rotary table having been removed. After the Kelly bar has been raised a suflicient distance, end surface 65 of fingers |50 abuts .against surface 52 at the lower terminus of each groove Continued raising of the Kellyv bar will result in lifting Kelly drive bushing C from its seat in the rotary table. inasmuch as lingers 59 are made of sufficient strength to carry the weight of Kelly drive bushing C in the aforedescribed manner, Kelly rod 50, together with Kelly drive bushing C', may be moved to .any desired point on the derrick, such for example as the rat hole. Since fingers 50` are made to t closely into grooves 5|, bushing C' and fingers 59 will retain their intended positions with respect to Kelly bar 50 and consequently Kelly bar 50, together with bushing C', may be returned to their normal positions in the well at the desired time without displacing fingers 09 from grooves 5 Inasmuch as fingers 00 shown in modification of Figs. 6 to 10, inclusive, are affixed to the lower end of bushing inserts 73, the sealing mechanism of this modification is brought into operative position within blowout prei/enter 53 at the same time it is desired to render bushing C operative for rotating Kelly bar 50.

Figs. 1l and 12 show still another modification of the sealing means and a mounting means therefor which may be employed in accordance with my invention. Rather than employing the` assembly A of Figs. 3 or 5 in conjunction with the hold-down means (assembly B) and the bearing arrangement shown in Fig. l, thev modification which is shown in Figs. 11 and 12 may be instead employed. In Figs. 11 and 12 circular framework |00 is shown as consisting of three segments, towit, |00a, |0027 and |000, although it will be understood that circular framework may be divided into a larger number of segments if desired. Each of the ends of segments |00a, |0012 and |000 are adapted to receive a pinv |0| for joining the said segments together to form circular framework |00. Circular framework |00 defines a central passage |02 of sufficient diameter to permit passage of kelly I0 of Fig. l therethrough and carries vertically extending fingers |03 arranged with the axis of said fingers on the circumference of central opening |02. Fingers |03 are spaced on the circumference of central passage |02 so as to coincideV with longitudinally extending grooves of kelly l0. The inner surface |00 of fingers-|03 is shaped to conform to the configuration` ofr grooves In the drawinginner surface |00v of fingers |05 isJ shown as arcuate in form to conform to theV arcuate configuration of groove of the kelly shown in Fig. 1 although it will be understood that grooves may be of any desired configuration and that surface |04 of fingers |03 is to be of corresponding configuration. A thin coating of deformable material |05,such, for example, asrubber, coverssu'rface |04 so as to provide a duid-tight seal between surfaces |04 and the surface formed by grooves when said fingers are placed in operative relation with the said grooves. The outer surfaces |00 of fingers |03 must necessarily be arcuate, the curvature being such that the outer surfaces |00 cooperate with the outer surface of kelly I0 when deformable material |05 is in sealing contact with curves lv of kelly l0, to form a cylindrical surface. The surface formed by outer surface |00 of fingers |03 and the outer surface of kelly l0 must necessarily be cylindrical in form .so-that the said surface may be rotated in sealing contact with surfaces` 20 of rams I9 shown in Fig. l. While the drawing shows six vertically extending fingers |03, it will be understood that the number of fingers must necessarily correspond to the number ofY grooves onithe outer surface of the kelly which is to be sealed".

Mounted on the outer surface of circular framework |00 is a plurality of radially spaced axles |01, the longitudinal ax'es of which pass through the geometric center of circular framework |00. Mounted onA each of axles |07 are beveled roller' bearings |08 which are adapted to rotatel about the axes of said axles. Each o1' said roller bearings |08A may be tapered outwardly as' shown.

Hold-down assembly Dconsists of hold-downv ring mettons' un and retaining nuts' lll. Hoid'- down ring |00 is shown as consisting ofl two seg- Ine'nts' USZ'aIid |090, although it will be understood that ring 09 may be divided into a greater number of segments. Segment |090 defines a pair of outwardly' extending ears ||2` at each of' its ends, each ear defining a port H3 while segment |09d defines a single ear I4 at each of its ends, ear I4 defining a port |5 which mates with ports ||3 in ears ||2. Segments |09c and |0911 are joined together to form ring |09 by mating ports ||3and ||5 and said ports.

Bing N30-defines on its inner surface an annular recess or track` I0 for receiving rollers |08. The upper surface H7 of annular recess ||6V is beveled downwardly and outwardly while the roller surface 8 is beveled upwardly and outwardly. Surfaces and ||8 are beveled so as' to receive rollers |08.

In employing theV modification shown in Figs. 11 and l2, in connection with kelly and blowout preventers shown in Fig. 1, segments |0011, |001) and |00c are placed on kelly l0 with fingers |03 fitted into grooves The aforementioned segments are then joined by means of pins |'0|. Segments |096' and |00d are then placed around ring |00 so that rollers |08` engage with track l0 as shown in Fig. 12. Segments |000 and IdV are then joined by means of bolts ||0 and retaining nuts' This assembly is then moved downwardly along the kelly to a point just above the blow-'out preventers at which time bolts ||0 are threadedly engaged with threaded wells IIB provided in housing of blow-out preventers I5.

A spacer |20 may be provided between ring |09 and housing il. When the assembly is mounted in the afcredescrib'ed manner, circular frame- Work |00, together with ngers |03, may be r0- tated in cooperation with the kelly while ring |09 provides a mounting on the blow-out preventer for roller bearings |08 carried by framework |00.

When it is desired to remove kelly' |0 shown in Fig. 1 from the axis of the borehole for any reason, ring |00, fingers |03 and ring |00 may be passing bolt H0' through permitted to remain on the kelly by merely disengaging retaining nuts l ll from bolts |||l, thus permitting ring IES to slip off the said bolts. If it is desired that ring |09 also remain on the kelly, temporary pins, not shown, may be inserted in ports ||3 and H5 to hold |090 and lllSd together, Ordinarily, however, segments |09c and I|l9d will be temporarily removed from their position on the kelly until the kelly is again returned to its position in the borehole. When the kelly is so returned and since framework and fingers |03 are already mounted on the kelly, all that remains to be done to secure framework |03 above blow-out preventer I5 is to again assemble ring |69 in the manner hereinbefore described and to secure ring |09 over bolts ||0 by means of retaining nuts I,

The nature and objects of the present invention having been fully described and illustrated, what I Wish to claim as new and useful and to secure by Letters Patent is:

l. A device for providing a fluid-tight seal between a grooved round kelly and the sealing means of a blowout preventer adapted to seal circumferentially a cylindrical surface comprising, in combination, a member defining la central opening concentric with the axis of the kelly and carrying vertically extending fingers, each nger defining an inner and outer surface, said fingers being arranged With their axes on the circumference of said central opening and having their inner surfaces fitting slidably and sealably in the grooves of the kelly and their outer surfaces cooperating with the outer surface of the kelly to define a uniform cylindrical surface.

2. A device for providing a fluid-tight seal between a grooved round kelly and the sealing means of a blow out preventer adapted to seal circumferentially a cylindrical surface comprising, in combination, a member mounted for rotation with the kelly defining a central opening concentric with the axis of the kelly and carrying vertically extending fingers, each nger defining an inner and outer surface, said fingers being arranged with their axes on the circumference of said central opening and having their inner surfaces fitting slidably and sealably in the grooves of the kelly and their outer surfaces cooperating with the outer surface of the kelly to define a uniform cylindrical surface adjacent the sealing means of the blowout preventer.

3. A device for providing a fluid-tight seal between a grooved round kelly and the sealing means of a blowout preventer adapted to seal circumferentially a cylindrical surface comprising, in combination, a circular framework defining a central opening concentric with the axis of the kelly and carrying vertically extending fingers, each finger defining an inner and outer surface, said fingers being arranged with their axes on the circumference of said central opening and having their inner surfaces fitting slidably and sealably in the grooves of the kelly and their outer surfaces cooperating with the outer surfaces of the kelly to define a uniform cylindrical surface, a mounting adapted to be removably secured to a blowout preventer and bearings arranged to support said framework for free rotation on said mounting.

4. A device for providing a fluid-tight seal between a grooved round kelly and the sealing means of a blowout preventer adapted to seal circumferentially a cylindrical surface comprising, in combination, a plurality of arcuate segments carrying vertically extending fingers, each finger defining an inner and outer surface, said segments being adapted to be joined to form a central framework defining a central opening concentric with the axis of the kelly with said fingers arranged with their axes on the circumference of said central opening and having their inner surfaces fitting slidably and sealably in the grooves of the kelly and their outer surfaces cooperating with the outer surface of the kelly to define a uniform cylindrical surface, a mounting means adapted to be removably secured to a blowout preventer and bearings arranged to support said framework for free rotation on said mounting.

5. A device for providing a fiuid-tight seal between a grooved round kelly and the sealing means of a blowout preventer adapted to seal circumferentially a cylindrical surface comprising, in combination, a plurality of members carrying means adapted to transmit rotative movement to said kelly and to permit longitudinal movement thereof, the inner surfaces of said members cooperating to define a central opening concentric with the axis of the kelly, vertically extending fingers, each defining an inner and outer surface, mounted on the lower end of said members, said fingers being arranged with their axes on the circumference of said central opening and having their inner surfaces fitting slidably and sealably in the grooves of the kelly and their cuter surfaces cooperating with the outer surface of the kelly to define a uniform cylindrical surface adapted to cooperate with the sealing means of the blowout preventer to form a fluidtight seal between said kelly and the body of the blowout preventer.

6. A device adapted to be used when deepening a borehole provided with a casing and having a blowout preventer mounted thereon comprising, in combination, a grooved round kelly, a member defining a central opening concentric with the axis of the kelly and carrying vertically extending fingers, each finger defining an inner and outer surface, said fingers being arranged with their axes on the circumference of said central opening and having their inner surfaces fitting slidably and sealably in the grooves of the kelly and their outer surfaces cooperating with the outer surface of the kelly to define a uniform cylindrical surface adapted to cooperate with the sealing means of the blowout preventer to form a fluid-tight seal between said kelly and the body of the blowout preventer.

7. A deviceadapted to be used when deepening a borehole provided with a casing and having a blowout preventer mounted thereon comprising, in combination, a grooved round kelly, a circular framework defining a central opening concentric with the axis of the kelly and carrying vertically extending fingers, each finger defining an inner and outer surface, said fingers being arranged with their axes on the circumference of said central opening and having their inner' surfaces fitting slidably and sealably in the grooves of the kelly and their outer surfaces cooperating with the outer surface of the kelly to define a uniform cylindrical surface adapted to cooperate with the sealing means of the blowout preventer to form a fluid-tight seal between said kelly and the body of the blowout preventer, a mounting adapted to be removably secured to the blowout preventer and bearings arranged to support said framework for free rotation on said mountlng.

8. A device adapted to be used when deepening borehole provided with a casing and having a blowout preventer mounted thereon comprising, in combination, a grooved round kelly, a plurality of arcuate segments carrying vertically extending ngers, each finger defining an inner and outer surface, said segments being adapted to be joined to form a circular framework defining a central opening concentric with the axis of the kelly with said fingers arranged with their axes on the circumference of said central opening and having their inner surfaces tting slidably and sealably in the grooves of the kelly and their outer surfaces coooperating with the outer surface of the kelly to define a uniform cylindrical surface adapted to cooperate with the sealing means of the blowout preventer to form a fluid-tight seal between said kelly and the body of the blowout preventer, a mounting adapted to be removably secured to the blowout preventer and bearings arranged to support saidsegments for free rotation on said mounting.

9. A device adapted to be used when deepening a borehole provided with a casing and having a blowout preventer mounted thereon comprising, in combination, a grooved round kelly, a plurality of members carrying means adapted to transmit rotative movement to said kelly and to permit 14 longitudinal movement thereof, the inner surfaces of said members cooperating to dene a central opening concentric with the axis of the kelly, vertically extending fingers, each dening an inner and outer surface, mounted on the lower end of said members, said fingers being arranged with their axes on the circumference of said central opening and having their inner surfaces fitting slidably and sealably in the grooves of the kelly and their outer surfaces cooperating with the outer surfaces of the kelly to dene a uniform cylindrical surface adapted to cooperate with the sealing means of the blowout preventer to form a fluid-tight seal between said kelly and the body of the blowout preventer.

ALBERT L. STONE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,831,956 Harrington Nov. 17, 1931 1,902,906 Seamark Mar. 28, 1933 2,126,007 Guiberson et al Aug. 9, 1938 2,287,205 Stone June 23, 1942

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