US2731281A - Kelly packer and blowout preventer - Google Patents

Description

Jan. 17, 1956 G. s. KNOX 2,731,281

KELLY PACKER AND BLOWOUT PREVENTER Filed Aug. 19, 1950 3 Sheets-Sheet 3 VIIIIIIIIIIJIIJ IIIIA GQANV/LLE 5: KNOX,

1NVENTOR..

fiTTaQA/Eys United States PatentO fiFice 2,731,281 Patented Jan. 17, 1956 2,731,281 KELLY PACKER AND BLOWOUT 'PREVENTER Granville S. Knox, Los Angeles, Calif., assignor to Hydril Corporation, Los Angeles, Calif., a corporation of Cali fornia Application August 19, 1950, Serial No. 180,480 Claims. (Cl..28616.1)

This invention relates generally to oil well drilling and control equipment and is more particularly concerned with improvements in kelly packers and blowout preventers.

As is well known, the drive from a rotary table to a drill stem is imparted through a grief pipe of non-circular cross section and commonly called a kelly. The cross section of the kelly is usually square or hexagonal but it may be of any non-circular shape which will give it proper drive characteristics.

Because of its non-circular cross section, it is not an easy matter to pack it off eifectively during stripping operations-that is, when the drill stem with its enlarged collars are being moved longitudinally through the well casing. It is therefore an object of the invention to provide particularly effective means for packing off the kelly during stripping operations and certain of my claims are drawn to that feature regardless of whether or not the kelly is rotating during the pack-off period, and there fore the fact that the description will be mainly directed to a packer which is effective during rotation of the kelly, is not to be construed as indicating that the invention, considered in its broader aspects, .is limited to the rotatable packer mounting which I will describe. In other words, the stripping packer is. here shown as being rotatable with respect to the main housing of the device, but this rotatable feature may be dispensed with if stripping, alone, is to be accomplished. And, as a matter of fact, the novel stripping packer, per se, has very considerable advantage in connection with packing off work in environments other than as here disclosed.

Of course, when the kelly, of polygonal cross-section, is rotating, the difiiculty of packing it ofi is increased markedly, and another. object of my invention is to provide means whereby that difliculty is completely overcome. Generally, this is accomplished by rotating the stripping packer with the kelly, rather. than rotating them relatively, and then sealing otf the member, of circular cross-section, which supportandrotates the packer.

The device is especially adaptedfor use in controlled pressure drilling and reverse circulation drilling, and has performed effectively with well pressures as high as 2600 pounds persquare inch while rotating up to 150 R. P. M. It is capable of being quickly put into operative condition when occasion for its usearises and is ,swift and sure of operation.

It is also an object of the invention to provide astrong, sturdy device which is exceedingly compact and, when installed, occupies but relatively little space. Further, I have provided novel, quick acting, and sure means for de tachably locking certain of the units together.

During pressure drilling operations, lengths of pipe can be added to or removed from the drill string without loss of time and without inconvenience. The stripper portion of the assembly need be removed from the rest of the assembly only when passing the'drillbit.

Another important object and feature of the device is the means whereby the-tightness of the seal around the rotating stripper-carrying member may be accurately controlled. It can be controlled with such delicacy that just suflicient leakage of well fluid is permitted to properly lubricate and cool the relatively rotating sealing surfaces.

Many other objects and features of the invention will be apparent from the following detailed description, reference being made to the accompanying drawings, in which:

Fig. 1 is a view, partly in section and partly in elevation, showing my device during the stage of assembling or disassembling the units thereof;

Fig. 2 is a view similar to Fig. l, but showing the units in assembled condition;

Fig. 3 is an enlarged, medial section of the device in a condition similar to that of Fig. 2, but omittingthe kelly and the representations of the rotary table equipment and of the fitting below the preventer;

Fig. 4 is a top, plan view of Fig. 3;

Fig. 5 is a section on line 55 of Fig. 3;

6 is a fragmentary section on line 66 of Fig. 4;

Fig. 7 is a fragmentary section on line 7-7 of Fig. 3;

Fig. 8 is a medial cross section through the packing ring shown in Fig. 7;

Fig. 9 is an enlarged fragmentary section on line 99 of Fig. 3;

Fig. 10 is a fragmentary section illustrating approximately the deformation of the stripper packer when it is engaged by the kelly;

Fig. 11 is a section on line 11-11 of Fig. '10;

Fig" 12 is a section on line 12-42 of Fig. 10;

Fig. 13 is an elevation of a modified. form of packer sleeve; and

Fig. 14 is a top plan view of Fig. 13.

In Fig. 2 there is illustrated a conventional rotary table 10 adapted to drivingly receive a central, non-circular, and spl'itmaster or table bushing 11 which, .in turn, drivingly accommodates a usual, non-circular kelly drive bushing 12. The kelly bushing has a non-circular, axial opening 13 to take the non-circular kelly 14 which .is coupled to drill string 15 in the usual. manner. The kelly and kelly bushing are relatively axially slidable, and rotative drive from the table to the kelly is imparted through the interfitting master and table bushings. .I have here illustrated the kelly and the mating opening of the kelly bushing as being of square cross section, but it is obvious that they may have other polygonal shapes.

The drill stem is entered in a usual well casing (not shown) to the upper end of which is coupled any suitable flow-fitting 1'6 i Theassembly 17 comprising my improved kelly packer and blowout preventer, is made up, in the main, of two cooperating units 18 and 19, unit 18 including a kelly stripper packing P, and unit 19 including sealing means .8 for sealing off unit 18 from an outer housing or body member 22 coupled to fitting 16 or to any other suitable fitting which may comprise the upper terminal of the well casing.

'Unit 19 may, in itself, comprise a blowout preventer eftectiveinormally to function as such ondrill pipe or in open hole when unit i8. is not being used, though this is not at all limitative on the broader aspects of my invention. For illustrative purposes I have shown, as a blowout preventer particularly well adapted to the present purpose, the device fully described and claimed in mycopending application entitled Control Head and! Blowout Preventer, Serial No. 691,110, filed August .16, .1946, now Patent No. 2,609,836 issued September 9, 1952, but this showing is not to 'be considered as limitative on my broader claims.

Cap member 23 of housing or .body member 22,.has a central bore '24 which opens to cylinder bore 25, the

pipe 27 is a packer actuator 29 having standpipe 27 is welded at its lower end to the housing and extends upwardly in bore 25. The lower end of pipe 27 has flow-passage notches 28. Annularly spaced from piston fit at 30, 31 and 32 (Fig. 3) with the opposing defining walls of bore 25. The piston head 33 divides a portion of bore 25 into chambers 34 and 35, said chambers being provided with flow passages 36 and 37, respectively, controlled by valves 38 and 39, respectively, whereby fluid under pressure may be selectively admitted to or exhausted from said chambers to cause controlled reciprocation of member 29 or to hold that member in adjusted position.

Actuator 29 has a downwardly converging, conical bore 40 within which is positioned the complementary, conical sealing member generally indicated at S. This member comprises a massive annulus 41 of natural or synthetic rubber or some other suitable resilient plastic. Neoprene having a durometer hardness of 65 to 70, has been found to be a suitable substance. Molded within the annulus are circumfe'rentially spaced, metal inserts 42 which comprise upper and lower plates or flanges 43 and 44, respectively, connected by vertical webs 45. It will be noted that the inner ends 46 of top plates or flanges 43 project radially inward beyond the immediately underlying portion 47 of annulus 41. The member S is held against vertical displacement by the engagement of insert flanges 43 and 44 with the underside 48 of cap 23 and the upper end of standpipe 27, respectively.

When actuator 29 is down in the position of Fig. l, the annulus 41 is inherently radially expanded to an extent which opens the major bore 49 of the annulus and the bore defined by flange ends 46 to extents approximately equal to the diameter of cap-bore 24. It will be seen that by admitting fluid under pressure to chamber 34 and relieving the pressure in chamber 35, actuator 29 is forced upwardly from the position of Fig. 1 and will radially constrict member S and thus reduce the diameter of its effective bore. The inserts 42, with their webs 45 and flanges 43, 44, control the flow of the plastic 41 and prevent harmful axial extrusion thereof, all as explained in detail in said copending application. As soon as the annulus closes about work of any nature, well pressure below member 29 is effective against piston area 50 to aid in further radially constricting the plastic annulus.

n the other hand, when fluid pressure is relieved from chamber 34 and applied in chamber 35 (assuming the actuator 29 is up in the position of Fig. 3) the piston is forced downwardly, and the resiliency of the annulus 41 restores said annulus to the radially expanded condition of Fig. 1.

Bolted at 51 to the upper face of housing cap 24, is an annular drain tray 52 whose bore 53 registers with cap-bore .24, and which tray has a conical positioning shoulder 54, whose purpose will presently be described. An annular cover ring 55 is bolted to the upper edge of the tray-flange 56 and clamped therebetween is a flexible wiper seal 56a made, for instance of molded Hycar. The drain tray has a drainage outlet pipe 57.

Unit 18 is actually assembled about kelly 14 (or some other element of the drill string) and then lowered into unit 19, but it will be more easily described by first assuming it is in the position of Fig. 3, in which figure the kelly is omitted in order to expose the full structure of the unit. Actually, the kelly occupies the bore of unit 18 when that unit is in the position of Fig. 3, and the packing member P will be deformed by the kelly to take approximately the shape shown in Fig. 10.

The housing 58 of stripper unit 18 includes a tubular body portion 59 and a relatively reduced, elongated and tubular neck-portion 60, the junction between the two portions being formed as a conical portion 61 which is adapted to seat on the conical positioning shoulder 54 when the unit 18 is lowered to the position of Fig. 3.

4 When in this position, wiper seal 56a, engages the outer surface of housing 58. The neck portion fits the capbore 24 with working clearance and its lower end 62 extends below cap 23 and, in this extended end, there is provided an annular groove 63 which, when positioning shoulders 54 and 61 are in engagement, lines up horizontally with insert-ends 46. The unit 18 is lowered into unit 19 when the latter is, in the condition of Fig. 1, neck 60 thus being passable, with annular clearance, through the bore of the ring formed by insert flanges 43. Then, when member S is radially constricted by raising actuator 29, as has been described, flange ends 46 enter groove 63 so as to overlie the square-cut, upwardly facing shoulder 63a defining the lower side of the groove and to pressurally engage the groove-bottom 64, thus releasably holding unit 18 against upward dislodgement from and rotation with relation to the unit 19. Continued elevation of actuator 29 causes the plastic material of annulus 41 to flow around the now-stationary inserts 42 and to sealingly engage another element of unit 18, as will be described later. Thus, flange ends 46, or more broadly, member S, form a releasable latch forholding units 18 and 19 in assembly, the latch, thus formed, being controllable by actuation of member 29. Ends 46 may be considered as latching fingers.

A composite tube 65 is rotatably supported within and by body member'59, this tube being made up of a bearing sleeve 66 and a stripper sleeve 67, the two sleeves being telescoped throughout the extent of sleeve 66, while the lower end of sleeve 67 projects downwardly below sleeve 66, and extends, with running fit, through the bore 68 of neck 60. The two sleeves are threadably connected at 69. The lower end of bearing sleeve 66 extends, with annular clearance, into the counterbore 70 of. neck 60, said counterbore communicating through ports 71 with drainage channels 72a sunk in the external face of neck 60 and opening at their upper ends to drainage tray 52.

Bearing sleeve 66 has an upwardly facing, annular shoulder 72 which is flush with the bottom wall 73 of housing-counterbore 74. Within this counterbore and bottomed on shoulder 72 and wall 73, is a stack 75 of radio-thrust bearings preferably, though not necessarily, three in number, and individually designated at 76a, 76b and 76e. This type of bearing not only serves well as a rotational bearing but also has exceptionally high rating as an end thrust bearing. The bearings 76a and 76b are axially separated from one another by outer and inner spacer rings 77 and 78, respectively. Bolted at 79 to the upper end of housing 18 is a bearing ringcap 80 which engages the outer race 81 of bearing 76a, there being vertical clearance 82 between the cap and housing, so by tightening bolts 79, the outer races of all the bearings are rigidly clamped between the cap and housing shoulder 73.

Screwed at 82 on the upper end of sleeve 67 is a drive ring 83, and between this ring and bearing 7 6a is a bearing-adjusting collar 84. This collar is keyed at 85 to bearing sleeve 66 and has an annular groove 86 to take upstanding flange 87 on ring cap 80. The flange and groove have running fit at 88, but vertical and annular clearances 89 and 90, respectively, are provided so ring 80 and collar 84 may be capable of relative vertical movement during the adjustment of the bearing 75, as will be described.

Adjusting collar 84 has a depending annular flange 91 engaging the inner race 92 of bearing 76a, and threaded through drive ring 83 are adjustment bolts 93 whose lower, unthreaded ends 94 are entered in sockets 95 provided in adjusting collar 84. By threading the bolts downwardly, adjusting collart84 is depressed in a manner to clamp the assembly of ring 78 and the inner races of bearings 76a, 76b and 76c in longitudinal compression. When the clamping compression is of the proper degree, 'a wire 96 is run through the heads of bolts 93 to releasably lock them, and therefore collar 84 and the bearing elements in adjusted positions.

Preferably a grease sealant ring-assembly 97 is provided between the relatively rotatable adjusting collar 84 and ring 80.

It will be seen that due to the described connection of parts, drive ring 83 acts as a head for composite tube 65, and that this head, in effect, suspends said tube and all parts carried thereby from the bearing stack 75, thus efiiciently mounting the tube for rotation with respect to housing 58. Bearings 76a, 76b and 76c are matched, precision, radio-thrust ball bearings, and the two lower bearings 76b and 760 are mounted in tandem so they equally share the load imposed by the upward thrust of well pressure against rotating tube 65. Upper bearing 76:: resists the comparatively small downward load imposed in passing tool joints down through packer P. The bearings are preferably pre-packed with grease. Greasegun fittings 98 which are in communication with passageways 99 provide means for introducing sealing-grease to the ends of the bearing assembly.

It will be seen that drive ring 83, adjusting collar 84, bearing sleeve 66, and stripper sleeve 67 are adapted to rotate as one when rotative force is applied to drive ring 83.

Mounted on the extended end of stripper sleeve 67 ata point just below neck 60, is a deformable packer sleeve generally indicated at 100. This sleeve is made of any suitable material and may be of various forma tions. For instance, in Figs. 13 and 14, is a one-piece, cylindrical, tubular packer sleeve 100a which may be made, for instance, of Hycar which is a synthetic rubber plastic having a durometer hardness of from 85 to 90. On the other hand, I may use the three piece sleeve shown in Fig. 3, each piece being made up of a ring 101 (see Figs. 7 and 8) of Micarta which is a synthetic which is dead hard and resilient. These rings are split at one side and have circumferentially overlapping portions 102, much in the manner of a piston ring. Corners 103 are preferably chamfered, as shown.

When sealing member S is constricted in the manner previously described, it sealingly engages the annulus 41 with hearing sleeve 100, and radially deforms said sleeve, whether it be of the type shown in Fig. 3 or in Fig. 13, in a manner to sealingly engage it with stripper sleeve 67. Thus, since the annulus is also sealed against actuator 29 and the actuator is sealed at 104 against housing 22 there will be, in effect, a horizontal sealing barrier extending from housing wall 22 to sleeve 67, and fluid under pressure with flow passage 26 will be unable, if the seal is sufficiently tight, to pass upwardly through housing 22 around the outside of sleeve 67. However, the radial constriction of packer sleeve 100 will not prevent rotation between sleeve 67 and the packing elements 'when sufficient torque is applied to sleeve 67.

As a matter of fact, it is a feature of my invention to provide means whereby the radial constriction of the sealing elements is so nicely controllable that just sufficient leakage of Well fluid between sleeves 67 and 100 is permitted to properly lubricate and cool the relatively rorating elements. That is, after a full seal is effected by forcing actuator 29 upwardly a suflicient distance, the actuator is controllably depressed to precisely an extent as will relieve the radial pressure between sleeves 67 and 100 sufficiently to permit the described slight leakage of well fluid. This is accomplishable regardless of the value of the well pressure encountered.

Ring 1% is held against downward vertical displace- 'ment along sleeve 67, by the spacing ring 105, which, in turn, is held up by the two-part or diametrically split mounting ring 106. The two halves of ring 106 are entejred in the annular groove 107 provided near the end of sleeve 67, after the removable stripping packer P is mounted on the sleeve. The ring halves are then bolted {at 108 to the packer, said assembly thereafter holding 6 the ring halves against separation and the ring, in turn, suspending the packer from sleeve 67.

Packer P includes ,a rigid metal armature generally indicated at 110, which is made up of rings 111 and 112 held in vertically spaced relation by integral bars 113. These bars are circumferentially spaced apart (Fig. 9) and may be considered, together, as making up ,an openwork cage. Each bar preferably has four vertically extending and equi-angularly spaced ribs 114. The angular spacing between the bars is preferably, though not necessarily approximately equal to the lengths of their minor axes 115. Preferably, also, the bars haveslight inward and downward taper.

Upper ring 111 has an internal horizontal flangeportion 116, a verticalflange portion 117, and, at the top of vertical fl'ange-117,-an external horizontal flange 118. Flange 117 fits nicely around sleeve 67, and, preferably, there is an O ring seal 119 between the opposed peripheral faces of the flange and sleeve.

Flange 118 takes bolts 103, and, when these bolts are tightened up, flange 116 is brought into tight contact with the lower end face 120 of sleeve67,

Armature 110 is preferably molded into the packerproper 121, this packer being in the form of a sleeve of resilient plastic material such as natural or synthetic rubber and preferably has a durometer hardness of from 65 to 70. The upper end 122 of sleeve 121 is molded over the top of armature flange 111. Externally, the sleeve 121 has a cylindrical portion 123, a short, upwardly and inwardly tapered portion 124 above the cylindrical portion, a downwardly and inwardly tapering por tion 125 just below the cylindrical portion, a cylindrical portion 126, amore sharply tapered portion 127, and a terminal cylindrical portion 128.

internally, sleeve 121 has a downwardly converging, tapered bore 129 leading to a cylindric bore 130 which is vertically spaced by the concavity 131 from the smaller-diameter and shorter cylindrical bore 132. An outwardly flaring bore 133 opens to the lower, free end of the packer sleeve.

The sleeve 121 thus has relatively thick walls 134 at its central portion, and a tapered lip formation 135' near its lower end which has a tendency to flex bodily outwardly about concavity 131 when a kelly is inserted therethrough.

The described formation of the armature 11! serves to anchor the material of the upper end of packer 121 so external well pressure will not objectionably radially collapse the upper end of the packer nor cause objectionable axial flow of the packer material.

However, the circumferential spacing of bars M3, permits the limited radial breathing of the packer necessary to the passage of drill string enlargements througl'l its bore.

As an example of relative sizes, I have found the following to give very satisfactory results. With a square kelly which is 3 /2" across the flats, the diameter of bore 130 may be 3%", the major diameter of cavity 131 may be 4" and the diameter of bore 132 may be 2%". When a kelly of such dimension is thrust through a packer having the given dimensions, the packer is deformed to take, approximately, the shape shown in Figs. 10, 11 and 12. The thick-walled central portion of the packer effectively grips the kelly but will not ordinarily engage the full faces thereof, and thus small voids, such as at 136, will be left (Fig. 11). The sealing lip 135 will, however, tightly engage the kelly throughout its perimeter. Then, when the well pressure is applied to the outer face of the packer, the voids 136 disappear, and the central portion 134 of the packer, as well as lip portion 135, sealingly engage the kelly and resist the elforts of even extremely high well pressure to cause leakage between the kelly and the packer.

In this condition, provided the seals from sleeve 67 to housing 22 are inoperative condition, the kellyis'fully packed off with relation to the housing, except for the slight lubricating leakage previously mentioned. When the kelly is rotated, the packer P rotates with it and therefor the non-circular cross-section characteristics of the kelly do not interfere in any way with the rotative movement. On the other hand the seals between such parts as do relatively rotate are on cylindrical surfaces, and therefore can be relatively easily accomplished. By reason'of the described arrangement, the severe Wearing and tearing effects which result from relatively rotating two sealingly engaged parts of which one, at least, is noncircular, are entirely eliminated.

. I will now describe the means whereby the rotative drive of kelly 14 is imparted to tube 65 and hence to packer P, so said kelly and packer rotate as one. Bolted at 137 to drive ring 83 is a driving head or ring 138 which has an annular groove 139 to take, with clearance, the heads of adjustment bolts 93. The head 138 has an internal flange 140 which fits the bore of sleeve 66, the flange being vertically extended to form lugs 141 which project into notches 142 provided in the upper end of sleeve 67. The notched-and-lug engagement helps in transmitting rotary drive from head 138 to sleeve 67 and also prevents the accidental unscrewing of sleeve 67 from sleeve 66. When it is desired or necessary to replace sleeve 67, it is merely necessary to detach head 138 from ring 83, and unscrew sleeve 67 from sleeve 66, it being noted that this replacement operation does not involve any manipulation or unlocking of the bearing adjustment bolts 93. Sleeve 67 is preferably made of steel which has been flame-hardened and thus has long service life, but when occasion finally arises for its replacement, the replacing operation is very simple and quickly accomplished.

In connection with replacement due to wear, consideration must be given to the fact that bearing sleeve 100 is exposed to severe wear effects. If replacement becomes necessary, it is an easy matter to dismount packer P, strip spacer 105 and sleeve 100 from sleeve 67, put on the new bearing sleeve, and remount the spacer and packer. However, it will be noted that the sleeve 100 may wear almost completely away before it needs replacement, for sealing member S is self-adjusting to the sleeve regardless of its diminished diameter. In fact, if sleeve 100 wearsaway completely, the sealing member S will adjust itself to and seal off directly against sleeve 67. While direct contact between sealing member S andsleeve 67 is not ordinarily to be desired because of the relatively rapid wear on annulus 41, it is not at all fatal if it occurs, and my invention broadly contemplates inclusion of a device in which such direct contact exists.

Driving head 138 has an enlarged counterbore 144, defined by vertical flange 145', adapted to receive the drive bushing 146 which, during certain stages of operation, bottoms on the upwardly facing shoulder 147. Bushing 1.46 may be of any suitable form which will transmit rotary drive from kelly 14 to head 138, but I have illustrated a preferred form which is particularly easily engageable with the kelly and with the head. The bushing is made up of upper and lower rings 148 and 149, respectively, each of which is diametrically divided so the rings may be readily assembled about the kelly. Thus each ring is made up of two half-sections 150a. The rings, which have square openings 150 to take the kelly 14 with working clearance, are arranged so the parting line 7 between the sections of one ring is normal to the parting line pa between the sections of the other ring (Fig. 4). It follows that when the rings are connected by bolts, the entire assembly of sections is held intact. It thus becomes possible to have vertically extending connecting bolts instead of radially or tangentially extending fastening means, thus leaving the entire outer periphery of the bushing available for driving lugs or the like.

Bushing 146 has a series of twelve circumferentially spaced, vertically extending driving lugs 152, though this number is not at all limitative. Each full lug is made up of a half-lug 152a on ring 148 which matches a halflug 15211 on ring 149, as shown in Fig. 6. The full lugs are pointed at both ends, as at 153, so the bushing may be reversed top for bottom if occasion arises.

Flange is provided with four, equi-angularlyspaced, vertical driving lugs 154 which are of a width to be taken between any two bushing lugs 152, and their upper ends are pointed as at 155. When bushing 146 is lowered into head 138 during a stage of the operation to be described later, lugs 154 enter between pairs of lugs 152, the pointed ends 153 and 155 acting as cams to rotate bushing 146 with relation to head 138 sufficiently to register the lugs and the between-lug spaces 152d if they are originally out of line. The lugs are of such arrangement and number that no matter where the head and bushing first engage, it will require only slight relative rotation to bring about full registration of lugs and between-lug spaces.

Preferably, split spacing collars 156, having square holes to take kelly 14, are arranged on the kelly between driving bushing 146 and the underside of kelly bushing 12. The sections 156a of each spacing collar are bolted together at 158 to hold them in assembly about the kelly. The collars 156 are supplied in a variety of thicknesses, so a selected number may be combined to make up an overall spacing element which will reach from bushing 146 to bushing 12 in any given installation. The combined spacers act to add the weight of kelly bushing 12, as well as their own weight, to the weight of bushing 146, to insure sufiicient force to cam-rotate bushing 146 to bring lugs 152 into registry with the spaces between lugs 154 if they are out of line when the bushing 146 first engages head I38. Spacers 156 also act to transmit upward force from bushing 146 to bushing 12 when the kelly is lifted sufiiciently to unseat bushing 146 from'head 138, as will be described, thus causing coincident elevation of kelly bushing 12 and freeing it from master bushing 11.

To describe the assembly and operation of the device, it will first be assumed that we are about to apply and use the device in connection with pressure drilling. However, the following discussion of step-by-step procedure is notto be considered as implying in any way that, this is the only procedure or the only order of steps that are feasible in the use of my device. Nor is it to be considered that the operations I will describe are the only ones that can be performed with the device.

We will assume that rising pressure in the well has warned the operator that he must prepare for pressure drilling and he has accordingly lifted the entire string from the well and has closed off the master valve (not shown) provided in the casing below fitting 16. The sealing member S of preventer unit 19 will be in the wide open condition of Fig. l. The bit (not shown) is detached from the drill collar C (since the bit is the only normal drillstring element which cannot be stripped through packer P). Drain tray 52 is bolted to preventer cap 23, and unit 1.8 is lowered into the bore of unit 19, but is not, at this time, locked in by latch fingers 46. Detachable hoisting eyes 158 on body 59 provide convenient means for applying a hoisting or cat-line to unit 18 for controllably lowering it to place. The drill collar is now dropped down through tube 65 and its lower end is forced through packer P, a tapered applying mandrel (not shown) being attached, if desired, to the lower end of the drill collar to aid in opening the packer to receive the body of the drill collar. The packer P now tightly and sealingly engages the drill collar.

The operator then lifts unit 18 out of unit 19 by hoisting the drill collar C, for the friction grip had by the packer P on that collar is sufficient to hold the unit from dropping off the collar-end. The device is now in the condition of Fig. l. The bit is screwed back onto the lower, exposed end of the drill collar C and unit 18 is again lowered into unit 19 by lowering away on the drill collar. The drill collar, by the way, will be provided with a usual back pressure valve (not shown) to prevent well fluid under pressure from subsequently passing upwardly through the drill string bore.

Sealing member S is now closed about tube 65 in the manner previously described, flanges 46 entering groove 63 in neck 60 to releasably lock units 18 and 19 together, and annulus 41 packing oil the tube 67 at packer sleeve 100, as previously described. Since there is now a seal completely about the kelly and the tube 65, the master valve is reopened and the drill collar is forced downwardly through packer P, which now is located within standpipe 27. The drill string is now made up stand-by-stand and gradually passed downwardly through packer P, said packer radially yielding sufficiently to allow tool joints (not shown) and other enlargements on the drill string to strip therethrough, but maintaining a seal on the drill pipe irrespective of its changing outside diameter.

When the string has been extended and lowered to about drilling depth, kelly 14 is applied to the uppermost stand. To this kelly there will have been applied the drive bushing 146, spacing collars 156 and kelly bushing 12, the assembly of bushings and collars being kept from dropping ofi" the end of the kelly by virtue of the shoulder 159 formed at the junction of the round and square portions of the kelly. The string is now further lowered by the kelly until lugs 152 on drive bushing 146 operatively engage lugs 154 on driving head 138, at which time the apparatus will be in the condition of Fig. 3, except that kelly 14 will occupy the bores of tube 65 and packer P, and the packer will have been deformed as in Fig. 10.

The kelly is now lowered to bottom the bit, and usual drilling operations are carried on by simultaneously rotating and lowering the kelly; tube 65 and packer P rotating as one with the kelly due to the connections described above. The kelly continues to be packed olf throughout the operation.

In coming out of the hole the operations are performed in reverse order, the tool joints being stripped through packer P but the seal being maintained constantly regardless of the changing effective diameter of the drill string.

While I have shown and described a preferred embodiment of my invention, it will be understood various changes in design, structure and arrangement may be made without departing from the spirit and scope of the appended claims.

I claim:

1. In a device of the character described, a housing having a vertically arranged, axial bore, a radially constrictable annular packing member in the housing and coaxial with the housing bore, means for controllably constricting said packer member and allowing it to expand; circumferentially arranged, rigid inserts carried by said packing member and individually movable radially inward and outward when the packing member is constricting and expanding, respectively, a second housing removably entered in the housing bore above the packing member, there being an external annular groove in said second housing exposed within the bore of the first housing and in the horizontal plane of said inserts, said inserts entering said groove when the packing member is radially constricted and thereby holding the two housings against vertical separative movement, a sleeve rotatably mounted in said second housing and held against axial movement with respect thereto, said sleeve extending through and below said packing member, the packing member being operatively constrictable about the sleeve, and a second packing annulus of resilient, plastic material attached to the extended end of said sleeve and radially constrictable to close upon work extending axially through the sleeve bore.

2. In a device of the character described, a first housing having a vertically arranged, axial bore, a radially constrictable annular packing member in the housing and coaxial with the housing bore, means for controllably constricting said packing member and allowing it to expand, a second housing removably entered in said housing bore above the packing member, an upwardly facing shoulder on the second housing, a latch member supported Within the first housing and movable to and from a position overlying said shoulder, said latching member, when in said position, positively holding the second housing against upward vertical movement with respect to the first housing, a sleeve rotatably mounted in the second housing and held against axial movement with respect thereto, said sleeve passing through said packing member, said packing member being operatively constrictable with respect to the sleeve, and a second packing annulus of resilient, plastic material on the sleeve and radially constrictable to close upon work extending axially through the sleeve bore.

3. A device as in claim 2; wherein said sleeve has an axial extension beyond said packing member, and said second packing annulus is mounted on said extension.

4. A device as in claim 2, in which said latch member is carried by the first mentioned packing member.

5. A device as in claim 2, in which said latch member is carried by the first mentioned packing member and is actuatable by constrictive and expansive movement of said first mentioned packing member.

6. A device as in claim 2, in which said second packing member comprises an armature connected at one end to said sleeve, the armature comprising a rigid ring secured to the sleeve, a plurality of circumferentially spaced, rigid bars connected to the ring and extending substantially parallel to the ring axis, and an annulus of resilient plastic material embedding said bars and having a portion extending axially beyond the free end of the armature, the plastic material which extends circumferentially from bar to bar also extending continuously, in a radial direction, from the inside to the outside peripheral faces of the annulus.

7. A device as in claim 6, in which said armature further comprises a second rigid ring embedded in said annulus and connecting the bars at their ends which are remote from the first mentioned ring.

8. A device as in claim 2; including also a bearing annulus mounted on said sleeve and held in the efiective horizontal plane of and engageable by said first packing member upon constriction thereof, said bearing annulus being radially contractible about said sleeve and into sealing engagement therewith, and being so contracted by forcible radial constriction of the first packing member thereabout.

9. A device as in claim 2, including also a bearing annulus mounted on said sleeve and held in the effective horizontal plane of and engageable by said first packing member upon constriction thereof, said bearing annulus comprising a plurality of split rings adapted sealingly to engage said sleeve when the first packing member is radially constricted thereabout.

10. A device as in claim 2, in which said second packing member comprises an armature connected at one end to said sleeve, the armature comprising an annular rigid, open-work cage, and an annulus of resilient plastic material embedding said armature, the annulus having portions extending radially through and beyond the cage and extending continuously from the inner to the outer peripheral faces of the annulus.

References (Iited in the file of this: patent UNITED STATES PATENTS 2,103,586 Kitchel et al Dec. 28, 1937 2,124,015 Stone et al July 19, 1938 2,145,458 Penick et a1 Jan. 31, 1939 2,159,541 MacClatchie May 23, 1939 2,163,813 Stone et al June 27, 1939 2,170,915 Schweitzer Aug. 29, 1939 2,170,916 Schweitzer et al Aug. 29, 1939

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