US2126933A - Well drilling equipment - Google Patents

Description

Aug. 16, 1938.]

F. STONE ET AL I 2,126,933

WELL DRILLING EQUIPMENT I Filed Aug. 12, 1935 7 Sheets-Shet 1 2,] wu c/rvbo w Frederirfi Sim W, flmeri Z. Si ma Aug." 16, 1938. F. STONE ET AL WELL DRILLING EQUIPMENT led Aug. 12, 1935 7 Sheets-Sheet 2 Aug. 16; 1938. F. STONE ET AL WELL DRILLING EQUIPMENT Filed Aug. 12, 1935 7 Sheets-Sheet 3 Frederic/I" 57012 ll lllrll [Irina-Ii!- g .fllberfl. Stone.

Aug. 16, 1938. F. STONE ET AL WELL DRILLING EQUIPMENT Filed Aug. 12, 193 7 Sheets-Sheet 4 Frederz'rk Sinne- Aug. 16, 1938. F. STONE ET AL 2,126,933

' WELL DRILLING EQUIPMENT Filed Aug. 12, 1935 7 sheets-she t 5 [/95 z0/ 204 2/0, 6 5 W M M X gvvuc/who'm Frederir Stone, .fllberil. Stone.

Aug. 16, 1938. F. STONE ET AL. 2,126,933 WELL DRILLING EQUIPMENT I Filed-Au 12, 1935 7 Sheets-Sheet e n25 I gwu /wbo'w Frederick Sta/1e, .Elbfirfl. 570116.

1933- ,F. STONE ET AL WELL DRILLING EQUIPMENT Fi led Aug. 12, 1935 7 Sheets$heet 7 [ATE/15b OPEN Fred/"12% Sfone, .fllberfl, 67mm LATCHED 00 NT Patented Aug. 16, 1938 2,126,933 I WELL DRILLING EQUIPMENT Frederick Stone, Los Angeles, and Albert L.

Stone, Redondo Beach, Calif., assignors to Hydril Company, Los Angeles, Calif., a corporation of California Application August 12, 1935, Serial No. 35,696

25 Claims.

This invention has to do with well drilling equipment and is more particularly concerned with equipment for drilling wells through formations where there is present oil or gas pressure of relatively high value, or where it is anticipated that such formations might be encountered.

It is not uncommon in certain'fields to drill through formation which develop an effective well pressure of 3,000 or more pounds per sq. in.

In order to control the fluid flow while drilling through such formation, it has become the practice to packoff, near the surface, the annular space between the casing and drill pipe. In going into the hole with the drill pipe and making it 15 up stand by stand, the pipe must thus be passed through the high pressure fluid within the casing. When the length of pipe in the hole is such that its weight is less than that of the effective well pressure tending to lift it, it will be 0 seen that it must be forced down until suflicient stands" have been added to the top of the pipe to allow the force of gravity'to sink it. On the other hand, in coming out of thehole, immediately after the balance point has been reached 25 (that is, the point where the pipe has been shortened by lifting it and unjointing stands from the top until the weight of the pipe left in the hole just balances the effective force of the well pressure tending to lift it) the well pressure tends to 30 eject the pipe from the casing.

The forceful entry of the pipe until after the balance point is passed by adding sufilcie'nt pipe lengths to overcome the-lifting force of the well pressure, is termed snubbing in, and the control of the movement of the pipe under the influence of well pressure in coming out, is termed snubbing out. It will be realized that with high well pressures, the lifting force exerted on the pipe becomes tremendous and if not kept under corr- 40 stant control may easily result in disaster, or, at

least, in causing great delay and damage;

The present invention contemplates the provision of particular efficient means for snubbing well pipe into and out of casing, with an assurance of control over the-pipe at all times, and as one feature has a plurality of controlling clamps of such a nature that if one fails another one automatically comes into play.

The device includes up-control slips which may 50 act either automatically or be manually adjusted to prevent upward movement of the pipe under the lifting tendency of the formation pressure when the snubbing means is released between snubbing strokes, and also includes down-control 5 slips which may act automatically or be manually adjusted to check the descent of the pipe if breakage should occur therein above the slips, or in the event of breakage of the cable. by which the pipe may be lowered or raised after the "balance point has been reached in "going in or before balance 5 point is reached in coming out.

The equipment has afurther feature which automatically prevents damaging action in the following event. Assume there is suflicient pipe in the well to overbalance the effective lifting force '10 of the pressure and that the pipe suddenly breaks at such a point that the broken-off portion extending from the surface is of insuflicient weight to overbalance the well pressure. In the absence of control means, this portion would be forcibly ejected from the well with tremendous speed, ordinarily too fast for a human being to take any counteracting action. Furthermore, in the event the drill'stem is in tension at the time of the break, it may previously have been stretched to the extent of several feet and the sudden parting will release'all the energy stored up during the stretching of the pipe and give added impetus to its upward movement. The up-control slips mentioned above provide means which act automatically to prevent such ejection in spite of the highest pressures which may be encountered.

However, the problem is even greater than merely that of checking the upward rush of the pipe, for such checking tends to cause the pipe to rebound thus loosening the up-control slip which may result in great damage by failure to reset the slips immediately and, at best, putting tremendous strains on the hold-down equipment when the effort to reset is made. With our equipvment, however, this rebound action is automatically checked by the down-acting slips, it resulting that the pipe may only move a very short distance in either direction and will finally and positively be brought to rest without excessive lohgi- 4o tudinal vibration.

The up and down control slips are manually or automatically shiftable into and out of operating positions through actuation of a single operating lever, or they may both be held by that same lever in neutral or inoperative position. Full stroking of the lever. in one direction moves one set of slips to operative position and the other set further from operative position (assuming the two slips were originally in a neutralor inoperative position) while a full stroke of the lever in the opposite direction reverses the conditions of the two slips. w

The invention has many other features of novelty, but these may be pointed out to bettlwad- 66" vantage in connection with the following detailed description of a preferred embodiment, reference being had to the accompanying drawings, in which: l

Fig. 1 is an elevational view, partly in broken away section, showing an embodiment of our invention Fig. 2 isa detached plan view of a centering thimble used in connection with our device;

Fig. 3 is a section on line 3-3 of Fig. 2;

Fig. 4 is a fragmentary section on line 4-4 of Fig. 2;

Fig. 5 is a fragmentary, enlarged medial sectional view, partly in elevation, of the yoke elements of our device;

Fig. 6 is a fragmentary, enlarged medial sectional view, partly in elevation, of the table elements of our device;

Fig. 7 is a top plan view of Fig. 5; v Fig. 8 is a view showing part of the elements in Fig. 5 but with certain of those elements inin closed condition, making up a part of our device;

Fig. 17 is a top plan view of Fig. 16; 1

Fig. 18 is a section on line 3-48 of Fig. 17;

Fig. 19 is a view similar to Fig. 17 but showing the clamp open;

Fig. 19a is a top plan view of a clamp or slipssetter similar to that of Fig. 17 but turned top for bottom; 7

Figs. 20 to 27, inclusive, are diagrammatic views showing various relative positions of the slip assemblies.

Our invention is adaptable to any suitable type of drilling equipment, though we have illustrated it as applied to a rotary table of the hydraulically raised and lowered type and to a drill pipe which has flush joint characteristics. This choice of illustration, however, is in no way to be taken as limitative on our invention, con sidered in its broader aspects. So also, while the slips are capable of operating to advantage in connection with any suitable supporting structure or spider, whether or not that structure be capable of rotation or 'vertical movement, our invention has been illustrated as applied in a situation where the up and down control slips are supported by the bushing of a vertical re-' ciprocable, rotary table. In this connection, so far as the operationof our improved equipment is concerned, that bushing is, in effect, a fixed part of the table, and therefore where our claims do not specify the supporting structure as of a particular nature,lthatstructure may be considered as of any suitable type and not'as limited to the showing.

Numeral I6 indicates generally a rotary table assembly or, what may be more generally termed a supporting structure or spider for the control slips later to be' described. This table is disposed centrally over well casing II and is adapted to operate the hollow drill stem or pipe l2 made up of sections I3 connected by tool joints I4, and

carrying at its lower end a bit or other tool l5.

of stem l2, past check valve l8, and out through the lower end of tool l5 at l5) passes outwardly from the casing bore through pipe I!) to any suitable treatment apparatus or storage facilities (not shown). Numeral 20 indicates conventionally a valve for controlling the flow through line l9.

Swivel 2| provides for the introduction of circulating or drilling fluid to bore I8, and also provides the means whereby drill pipe I2 is held suspended, lowered, or raised by tackle 22 which leads to'usual hoisting drum and brake equipment (not shown).

We will describe in some detail the particular rotary table or slip supporting structure here illustrated in order better to describe a physical embodiment of our invention, without intending in any way to.limit the broader aspects of that invention to the showing or description. Pistons and piston rod assemblies 23 are mounted for vertical reciprocation within cylinders 24 and carry head 25 upon which rotary table 26 ismounted. Fluid pressure admitted selectively to the tops or bottoms of cylinders 24 by control of valves 21,

28, in lines 29 and 30, respectively,- causes or controls the vertical reciprocation of head 25 and,

hence table 26. Table 26 is mounted for rota tion on bearings 3| (Fig. 6) supported on internal flange 32 of head 25, sleeve bearings or bushings -33 serving to maintain the table and particularly its sleeve portion 34 which definestable bore 9, in proper alinement. Bearings 35 interposed between the underside of flange 32 and the top of sleeve-carried flange 36, hold the table against upward separative movement with respect to I, head 25. Table 26 has an internal ring gear 31 whereby the table is rotated throughpinion 38 imparted to the table is transmitted to the/ bushing. I

The lower shoulders 4| of heads 4| (Fig. 9) engage table 26in a manner to prevent the bushing from dropping through the table bore, while looking pins 43 (Figs. 9 and 13) which aremounted for horizontal reciprocation through table walls 44, are adapted to be projected into sockets 45 provided, one each, in halves 42a and 42b of bushing 42, the locking pins thus releasably holding the bushing from being lifted clear of the table. Pins 43 are adapted to be reciprocated to and from looking or projected positions by vertical stub shafts 41 (Figs. 6 and 13) which have gear teeth engagement-48 with rack teeth 49 on pins 43. Shafts 4'! may be rotated by a socket wrench applied in their axial sockets 41' (Fig. 12) which are exposed at the top of the table.

As will be later described, pipe or work gripping means are mounted in bushing 42 whereby that work may be held against rotation and against vertical movement with respect tothe bushing, it following that rotation of the'table through Gil may be rotated to perform operations within the casing bore. Y

Bushing t2 becomes the direct support for certain wedge slips or work gripping assemblies to be described. But, as mentioned at the forepart of the specification, since this bushing is fixed against movement with respect to table 2%, that table (and this is true whether or not the table is rotatable or vertically reciprocable since it may more broadly be considered as a spider") may be considered as the supporting means for the work gripping assemblies, and broadly speaking, the bore characteristics of the bushing might just as well be considered as formed directly in the bore of the table, so far as our broader claims 7 are concerned.

However, for purposes of describing the illustrated embodiment of the invention, reference will be had to bushing 32 as the supporting member for the slips or as a slip-receiving body member. This body member has oppositely tapering, conical sockets or bores bill and (Figs. 6 and 9) the wall 52 of the upper socket converging inwardly and downwardly, and the wall 53 of the lower socket converging inwardly and upwardly.

An annular groove 5 is provided at the junction of bores '58, El, within which groove is seated a thimble 55 for centering stem 62. The thimble is removable in order to clear the bore of the bushing for passing'shoulder vmembers, such as bit l5, therethrough, and also to permit the substitution of different sized thimbles to take work of diflerent diameters. In Figs. 2, 3 and 4 we have shown the preferredform of thimble, this being in the nature of a halved ring having its inner peripheral wall oppositely chamfered as at 56. Ring-halves 55a and 55b are hingedly connected at one side by link 5i. When the halves are swung together, the ring is of sufficiently small diameter to be passed through the smallest portion of the bushing-bore. When it has been lowered to a position of horizontal alinement with groove 5 the free ends 58 are spread apart, thus projecting the ring-halves into the groove. This spreading is accomplished .by taking up screw 59 which connects the oppositely tapered wedge blocks 50 interposed between the free ends of the ring-halves, the inclined faces El of the wedge block camming the ends of said halves apart in an obvious manner and then serving to hold them apart so the ring is maintained in position within groove 5%.

Within socket 50 is provided the wedge slip as- 1 sembly or radially expansible and contractible work gripping means generally indicated at C, this assembly (Figs. 9 and 13) being made up of segmental wedge slips 52 (provided in any suitable number, here shown as three) each having a vertical, serrated face 63 in which the teeth preferably point upward, while the opposite face 64 extends at an angle complementary to and is adapted to engage socket wall 52. As is true in all slips of this character. the inclined face of each slip is cut back at 64c (Fig. 13) so the actual area of contact with the socket wall is reduced for rea-; sons well understood in the art. However, iii order to avoid confusion in the vertical sectional views, this clearance is omitted. Each slip has a tongue or dove-tail key 65 extending longitudinally along face 64 and entered in a complemenin either direction they simultaneously move radially of the body or bushing inwardly or outwardly. Thus, when slip-assembly C is raised, it may be considered as radially expanding or moving toward release position, and when the assembly is moved downwardly it may be considered as moving into radially contracted or work gripping position. When assembly C is inthis last named position (see Fig. 9) it will be seen that stem i2 is held from dropping downwardly with respect to the table, that upward movement of the table will act through the slips assembly to lift stem l2, and rotative movement of the table will impart like movement to the work through bushing 42 and the slip-assembly C. Slip-assembly C may thus be considered as down-control gripping means.

An up-control gripping means or slip-assembly generally indicated at D is mounted within socket 5i and, with the exception of certain characteristics to be described and the fact that the teeth .of its serrated faces 68 point downwardly, is gen- 65 and way 66, respectively. With this mounting in effect, it will be seen that upward vertical movement of assembly D moves that assembly into radially contracted or work gripping position, while downward movement of the assembly causes it to move to radially expanded or inoperative condition.

Surrounding stem it with annular clearance and at a point above assembly C, is a slip-suspension ring it (Figsx and 12) disposed over segmental slips 62. A two-part shifter ring ll, made up of halves bolted together at it, loosely encircles ring it, being received within ring-groove l9. Diametrically opposite trunnions tll on shifter H are taken within the slots Bl provided on the ends of forked arms'tfi, the latter being formed integrally with operating lever 83 which is pivotally and removably mounted at 8% on bracket 35. Bracket 85 is detachably held to head '25 within a socket 86 (Fig. 6) on the latter; Bracket 85 and arm 83 are thus held stationary with respect to head 25, but ring 75 is capable of rotation within shifter W, so the lever and its connections do not prevent relative rotation between head 25 and table 26 with its appurtenances. In the drawings arm 83 and bracket t5 are displaced from their normal positions to bring'them into the same viewing plane as the rest of the table-mechanism, and therefrom the arm is shown as though a portion were broken out to avoid interference with the yoke piston rod, to be described.

Ears .90 depend from ring 85 toward the underlying slip segments 62, a pin M connecting the upstanding lug 92 on each slip segment with the corresponding ear 90. Pins 8i extend through slots 93 in cars 90, these slots allowing for the relative horizontal shift of the wedge segments with respect to the lifting ring when said segments are raised or lowered, and preferably the slots incline downwardly and outwardly, as clear- 1y shown in Fig. 9, so their lower walls 9-1 may have camming action against pins 9! when the lifting ring is raised and thus aid in spreading the segments relatively apart as the slip assembly is lifted.

Lever 83 terminates in handle 95, adjacent to which, under certain operating conditions, there may be applied a weight 96 which tends to rotate lever 83 in a clockwise direction, as viewed in Figs. 6 or 9. Weight 96 may be suspended from lever 83 by hanger bolt 91 and may include provision for adding or taking away fractional weight elements 98 to secure proper balancing effect.

Suspension bolts I 00 (Figs. 6, 9, 12 and 13) depend from ears IOI on ring 15, extending, with lost-motion clearance IOI through that ring, through clearance holes I02 in bushing 42 and through clearance holes I03 in ring I04 which encircles stem I2, with annular clearance, below slips 99. Bolt heads I05 and nuts I06 thus support ring I04 in vertically spaced relation with respect to ring I5, limiting the extent of down ward movement allowed to slips 69. However,

due to theloose mounting of the suspension bolts within the rings said rings are capable of independent movement, within certain limits, the purpose of which will be hereinafter made apparent.

For the purpose of setting forth the operation of the slip mechanism so far described, reference will first be had to Fig. 6. Weight 96 has such efiective force-in tending to swing lever 83 in a clockwise direction in that figure that it just slightly overbalances the weight of the two slips assemblies and all appurtenances supported thereby, some of which are yet to be described. Accordingly, in Fig. 6 to which reference is now being made, it is assumed that the operator is holding up slightly on handle 95, just sufliciently to overcome the otherwise overbalancingefiect of weight 96 and to maintain assemblies C and D in neutral or release positions, both of these assemblies being radially expanded to an extent where their serrated faces clear pipe I2. Now if handle 95 be depressed or if the operator merely releases his hold on that handle to allow weight 96 to exert its full force, the clockwise rotation of lever 83 acts to raise ring 15, (Fig. 11) thus lifting slips 62 and spreading them radially outward to a greater extent, and, through suspension bolts I00 and lifter ring I04, raising assembly D and thus radially contracting it so its individual slips 88 are driven into wedging and biting engagementiwith stem I2.

If, on the other hand, starting from the neutral position of Fig. 6, handle 95 be raised, the counterclockwise movement of lever 83 lowers assembly C into socket 50 (Fig. 9) and hence into a position of radial contraction and wedging engagement with the pipe, and, through bolts I00 and ring I04, further lowers assembly D so its individual slips 69 spread further apart .to'positions of full radial expansion.- Situations. in which these operations are performed and the conditions which they bring about, will be discussed later.

It will be noted however, that when the slips assemblies are lowered by counterclockwise rotation of the operating handle to set, the upper slips assembly C and to lower assembly D to 9,

position of full expansion (Fig. 9) the sliding fit between ring I04 and bolts I00 will allow subsequent movement of assembly D upwardly independently of assembly C and into set position if lifting force be applied independently to ring I04. If the slips assemblies both be in neutral position (Fig. 6) the sliding fit between ring Rings IS-I04, and bolts I00 taken together may thus be considered a slip carriage or actuating assembly R (Fig. 6) controlled by lever 83, whereby both the upper and lower slips may be simultaneously shifted in a manner to set one assembly and release the other, or may be utilized to hold the assemblies in neutral positions, or to allow the slip assemblies to be operated independently by means now to be described.

An automatic setter for assembly D is indicated generally at E (Figs. 6, 9 and 16 to 19, inclusive) this setter being in the nature of a releasable clamp carrying auxiliary wedge slips IIO, the tapered body and teeth of which point in the same direction as slips 69 and their teeth 68. Slips setter E consists .of a tubular body III made up of halves H2 and H3 pivotally connected at H4 and each provided with external flange II5. Bracket flanges II6 (Fig. 9) preferably welded or otherwise suitably attached to the underside of ring I04, extend, one each, beneath flanges II5 to support the setter from the ring, or more broadly, from carriage R, but sufiicient clearance is provided to insure that flanges II5 may slide horizontally over brackets IIIi to enable the opening and closing pivotal movement of halves H2, H3 and also to allow the entire assembly E, when clamped to stem I 2, to rotate with that stem and with respect to carriage R under such operating conditions as may occur during rotation of pipe I 2 with respect to table 26.

Wedge slips I I0 are mounted for vertical reciprocation through ways II'I (Fig. 18) in body member I I I,the radial outward'faces I I8of these ways inclining inwardly and upwardly andthe slips having lateral keys II 9 entered in complementary ways I20. It follows that vertical movement bf slips I I0 is accompanied by horizontal translation thereof, they moving radially inward toward operative or gripping position when they are shifted upwardly through the ways, and being radially retracted to expanded or inoperative position when they are moved downwardly through the ways. The extent of vertical movement allowed to slips H0 is established by a ring-half I 2| bolted at I22 toeach half of. the body member, and weld-plug I23 provided at the upper end of each way.

' At the free end of body section II2 a trunnion block I24 is pivotally mounted in vertically spaced ears I25, keeper straps I26 being welded across the openings of ear-notches I2'I to maintain trunnion pins I28 in said notches. The threaded shank I29 of eye bolt I30 extends, with clearance, through trunnion block I24, a pin I3I pivotally connecting the eye I32 of bolt I30 with the fork T arms I33 of operating lever I34, the latter being pivotally connected at I35 with ears I36 on bodyhalf II3. Compression spring I31 on bolt I30 is interposed between block I24 and adjustment and lock nut I31, I38, respectively, While the bolt also carries an adjustment and lock nut I39 and I40, respectively, at the other side of block I24. When lever I34 is swung to the position of Fig. 17, bolt I30 is drawn to the right and acts through nut I31 and spring I3! to draw halves H2 and H3 into closed or operative position, the power of spring I31, as regulated by adjusting nuts I37 and I38, being such that slips IIO are frictionally engaged with stem I2 when said slips are in the lowermost position, as in Fig. 18. However, the

spring is adjusted so it will not close the body with sufficient tightness to cause any appreciable biting engagement of the slips III! with the pipe and will allow downward movement of the pipe with respect to the slips, but upward movement of the pipe will lift the slips into wedging positions. If there be any irregularities on the pipe surface such as would tend to spread the body halves apart during downward movement of the pipe, spring I31 allows this slight spreading action to take place without damage to any of the clamp parts.

It will be noted that when lever I35 is in the position of Fig. 17, pin l3l has passed behind a line common to centers I28 and I35, a self-lock thus being accomplished. However, in order to insure against any possibility of accidental release, a locking pin llll may be dropped through holes provided in arms I33 and behind lug IEE-on eye I32, which will prevent clockwise movement of lever I36, as viewed in that figure. A storage socket I53 on lever I35 takes pin I ll when not in use and the pin may be chained to the handle as at M4 to prevent its loss.

Assuming now the slip assembly D is in the condition of Figs. 6 or 9 and setter E is in the condition of Figs. 6, 9 or 18, if pipe l2 starts upwardly under the influence of well pressure from below, the frictional engagement of slips ill) with pipe I? will cause those slips to be carried upwardly along with the pipe and thus be wedged between the pipe and body lll, resulting finally in lifting that body and with it the ring llll, sliding that ring upwardly along bolts Hill and hence wedging slips 69 between pipe l2 and bushing 12 to radially contact assembly D (see Fig. 10) and thus check further upward movement of the pipe with respect to the table bushing.

When setter E is in the closed position of Fig. 17, nut I39 is spaced from block I26 so as to avoid interference with the body-closing action of spring I37. However, with key l ll removed, clockwise rotation of lever l3l towards the position of Fig. 19 moves nut I 39 into contact with block I23, whereupon further movement of the lever forces open the setter body, thus clearing slips ill) from pipe l2.

The automatic setter for the down-control slip assembly C is indicated generally at B and is of the same construction as setter E but is turned top for bottom (Fig. 19a) so that its slips l (Fig. 9) point in the same direction as slips t2 and so its teeth l5l point in the same direction as teeth 63. Since the structure is otherwise the same, similar numerals except for the addition of the exponent a have been applied to its elements, so the above description of setter E may be applied to the structure of setter B.

Flanges l l5a here rest on top ring l5, the fiange on one body half l Isa preferably being welded at MS or otherwise suitably secured to the underlying lifter ring it. However, this ring is preferably capable of sufiicient horizontal movement with respect to bolts Hi2 and shifter ill to allow the wedge segments I50 of the clamp half which is welded to ring ill to be cleared from pipe l2 when the setter is fully opened up to a position corresponding to Fig. 19, though of course in this case the setter is reversed side for side .with respect to the showing in that figure. When setter B is closed, as in Fig. 19a, its spring I3la maintains slips I50 in frictional contact with the pipe l2 but does not prevent upward movement of said pipe with respect to the setter or, considered otherwise, does not prevent the downward movemerit of assembly C with respect to bushing 42 or downward movement or carriage R. However, should the pipe suddenly start to drop due to breakage above the table, the pipe will carry slips I50 with it, wedging them between the pipe and body Illa (Fig. 9) and then carrying setter B,- ring I5, and slips assembly C downwardly, overpowering weight 96, and thus causing slips assembly C to be radially contracted into operative or gripping positionpnd thereby preventing further descent of pipe l2.

In this connection it will be noted that where weight 96 is not employed, the operator must exert a continuous pressure downwardly on handle 55 in order tohold slips assembly C out of work gripping or operative position, and 'under such conditions if the operator should release his hold on handle 95, slips assembly C will drop and thus be automatically set to prevent dropping of the pipe. However, when weight 96 is used, it is preferable (though not necessary) that setter B be closed'about the pipe during all periods except when the pipe is being intentionally lowered or when table 26 is being raised, with the pipe remaining stationary, (as during actual drilling-head operation) so slips assembly C will be automatically set by setter B in the event of breakage above the table which would otherwise allow the pipe to drop, for, if the operator fails to lift handle 95 under those conditions, or if he releases his hold on the handle, as he is very apt to do in his attempt to get out from under in the event a break suddenly occurs, weight 96 would prevent the setting of slips assembly C.

The equipment so far described is fully operative irrespective of the means used for snubbing in or snubbing out the pipe, or it may be used Where snubbing operations are not being actually employed but where there is a possibility that excessive well pressures may be reached in drilling down. We willnow proceed to describe a particularly effective type of snubbing mechanism which is novel, not only in itself, but also in association with the-slip and slip operating mechanism above described and which, during the snubbing in or out operations may be considered as a part of the snubbing equipment. I

Numeral I68 indicates generally a snubbing yoke made up of two side bars Mil which are spread apart at their centers to take drill pipe l2 and certain clamping mechanism, and are brought together at their ends, bolts lfiE and spacer blocks I63 holding the side bars in proper fixed position. The yoke is'supported on piston rods lfil carrying pistons l 65 (Fig. 1) which are mounted for reciprocation within cylinders llili, here shown as being attached through heads lfi'l to the stationary cross head N38 provided at the top of cylinders i l. By admitting fluid under pressure alternately to the opposite ends of cylinders I166 through, lines it? and l68, as controlled by valves llll and lll, respectively, yoke llill may be reciprocated or controlled in its reciprocation.

Preferably, theupper section 672' (Fig. 5) of each piston rod Hi l is detachably connected as at H3, so the yoke may be readily removed from or attached to the equipment during diiferent phases of operation. Brackets ll i, welded to sections ll2, carry at their upper eolres guide flanges llli to take the lower edge of yoke I60 while adjusting screws I'll carried by the brackets engage the under side of the yoke to allow for proper lining up of the yoke and piston rods and for maintaining them in proper relation.

The yoke clamp or slips assembly is generally all her or slips-socket I18 which is flattened at I18 (Fig. 15) to flt between yoke arms iii, and has a heavy base flange I88. Head casting I8I has a bore I82 in alinement with the bore I88 (Fig. 5) of body I18, and preferably is made up of halves I8I' (Fig. 14) bolted together at I84, the halves being individually welded to the underlying yoke arms I8I. A head flange I88lhas a depending tubular portion I81 which fits. within the bore I82, and compression bolts I88 extend from flange I88 to flange I88, serving to hold body I18 up and to hold flange I 88 down against opposite sides of bars I8I, thus rigidly tying together all the parts so far mentioned. In Figs. 5 and 8, a section of pipe I2 has been broken away to disclose parts which would otherwise be hidden thereby.

Tube I89 is mounted in the bore of flange I 88 and its extension I81 for vertical reciprocation, this tube functioning as a slips-releaser, or depresser, as will appear. Welded to the lower end of tube I89 is a collar or shoe I98 having a plurality of angularly spaced slips-depressing fingers I9I which project downwardly into slip ways I92 (Fig. 15) in body I 18. These slip ways are provided in any suitable number and their radially outward faces I92 incline upward and inwardly as clearly indicated in Fig. 5. Since these ways open to bore I82, their inclined faces may be considered together as deflnlng inwardly and upwardly converging walls.

' Slips I83, one for each way, are mounted for A vertical reciprocation with'respect to body membea I18. Their inner faces are serrated with downwardly pointing teeth I94 while their outer faces carry lateral tongues I 95 (Fig. 15) engaged in complementary grooves I96 which open to ways I 92. It follows that vertical movement of the slips causes simultaneous horizontal translation thereof, so upward movement of slips assembly A with respect to body member I18 radially contracts the slip assembly, and downward vertical .movement of said assembly causes simultaneous radial expansion thereof.

Engaging the top of tube I88 is a cross head 288 from which extend the diametrically opposite bolts 28I, the latter passing with clearance through holes 282 in flange I88 and through holes 283 in plates 284, the latter being welded on top of flange I88. Bolts 28I carry at their lower ends "a slip-supporting and setting ring- 285 which extends horizontally beneath the lower ends of slips I 98. On the other hand, flngers I 9| engage the upper ends of slips I98, it following that vertical movement of the slip carriage generally indiated at T (and made up of cross head 288, tube I88, flngers I8I, ring 285, and bolts 28I) in either direction with respect to the yoke and body I18 causes coincident vertical and horizontal movement of the slips and thus moves them into and out of gripping or release positions. Thus, the slip assembly A is radially contracted or moved into setting position by upward movement of carriage 'I' and is radially expanded by down movement of that carriage. Individually, ring 285 may be considered as a slips setter, and flngers I 9| as slips depressers or releasers, and the slips are depressible to an extent that their radial movement is sufficient to open up a bore of a size to pass shoulder elements on pipe I2,' such a bit I8.

I Compression springs 288 encircle bolts 28I 'between'cross head 288 and plate 284 and thus tend constantly to raise carriage T and move slips assembly A to operative or gripping position.

However, during-certain phases of operation, it

1 2,120,933 indicated at A and includes a tubular body membecom, necessary or desirable to hold the carriage its lowermost position against the action of spring 288 and thus hold the slips assembly A in radially expanded or released position. While any suitable type of latch may be employed, we have here illustrated a bar' or latch member 2I8 which is pivoted at 2 to' lifter ring 285, spring 2I2 tending constantly to rotate this latch in a counterclockwise direction as viewed in Fig. 5. Throughout the normal stroke of carriage T, the edge 2| 3 of latch 2I8 merely slides along the lower corner of flange I88, but if ring 285 be separated from flange I88 bymore than its normal stroke, for instance, by holding down on cableloop 2 (depending from ring 285) while yoke I68 is raised, spring 2I2 will rotate latch 2| 8 beneath flange I88, notch 2I5 being provided for thereception of the-flange corner, and the latch thereafter prevents upward movement of the carriage to return the slips to operative or radially con- .tracted position until said latch is manually released by swinging itagainst the action of spring 2I2. This release may be accomplished even though the-yoke be near the upper limit of its stroke, through the medium of cable 2I6 applied through link 2I1 to offset lug 2I8 on latch 2I8.

Without attempting to discuss all the various manners and situations in which our equipment may be used, we will describe briefly a few typical operations. For this purpose reference will be had particularly to Figs. 20 to 27, inclusive, wherein the elements are indicated diagrammatically. In these views, where the slips are shown in dotted lines they are to be considered as out of engagement-with the drill stem (for instance, clamps B or E would be open, as in Figs. 6 and 19, respectively; slips A would be ,latched open, as in Fig. 8, and assemblies C or D would be out of pipe engaging position, for instance in the neutral'position of Fig. 6); where the slips are indicated in full lines but with no hatching within them they are to be considered as engaging but not gripping the drill stem, so they will allow the stem to slide or-ratchet through them in one direction, but will grippingly engage the stem if it'starts in the other direction,

(for instance, clamps B or E would be closed but the slips therein would be relatively radially expanded); and where the slips are indicated in full lines with hatching within them, they are, to be considered as being wedged into gripping engagement with the drill stem.

Figs. 5, 6 and 20 illustrate the condition of parts on the down-stroke of the yoke in snubbing-in.

In this situation, the operator holds up on handle to hold the stem down against well pressure) assembly E will be carried up by the pressurelifted pipe and will set assembly D, as has been previously described, to check further upward movement of the pipe. Or if the operator depresses handle or if he drops the handle and thus allows weight 88 to act, the resultant upward movement of carriage R. will set assembly D, leaving E in the condition of Fig. 11. When assembly I) is automatically set by the upward movement of setter E (Fig. 10) assembly C will remain in its neutral position, for ring I04 will merely ride up on bolts I02. Where assembly D is set by depression of handle 95, either manually or by allowing weight 96 to act automatically (Fig. 11), assembly C willbe lifted higher to a position of full radial expansion.

As the yoke starts up to take a new bite on the pipe, the well pressure acts to raise the pipe and setter E along with it, thus setting assembly D, as has been described, and the parts are in the condition of Fig. 21, setter B either being left open or being manually closed,asthedriller may elect, but in neither event does it resist upward movement of the pipe. As soon as upward movement of the pipe is checked by assembly D, further upward movement of the yoke has the efiect of depressing fingers [IN to withdraw slip-teeth H96 from biting engagement with the pipe, whereupon carriage T travels upwardly with the yoke and slips ass ratchet over the pipe, ready to take a new grip when the yoke starts down again. If, during the upstroke of the yoke, assembly D fails for any reason, the upwardly forced pipe will carry yoke slips E93 with it and thus set them in a manner to put the pipe under the control of the yoke. If, as a precaution, setter B has been closed during the upstroke of the yoke, it must be reopened before the downstroke'is started.

After the balance point, as defined above, has been passed, the pipe is lowered in by cable, in which case the elements are put in the condition of Fig. 22, the yoke slips either being latched open (in a manner to be later described in connection with another operation) or the yoke entirely removed. In this case assemblies C and D are held in neutral or release positions (Fig. 6) setter B is opened, and setter E is closed, though it does not resist downward movement of the pipe. If, however, the pipe breaks below E, so the weight of the upper broken-d portion thereof is insuficient to overcome the well pressure tending to lift it, setter E is carried. up by the pipe and automatically sets assembly D, as previously described. If setter E should fail or if it happened to have been left open, the operator, merely by dropping handle E35 and thus putting lever t3 under the control of weight 95, may cause an elevation of carriage R and thus set slips D.

Fig. 23 illustrates 'a situation where the stem is supported in slips assembly C and being rotated by them through table-rotation, it being assumed either that weight 26 has been removed. or that the operator is lifting handle at torlower assembly 0 into operative or set position. In the event of a breakage such as that described in connection with Fig. 22, setter E will act to set assembly D, also as described in connection with that figure. Assembly C will check such rebound of the pipe as may be caused by the action of assembly D in suddenly checking the up-rush, and the pipe will thus be brought to rest with minimum longitudinal vibration and with minimum extent of travel in either direction. If weight 96 has been left on lever 83 during this period and the operator releases his hold on handle iii; (which'otherwise would result in assembly-C going to full release position) setter B will come into play as the pipe starts down on its rebound stroke and thus automatically set assembly C, in spite of weight 96, and check the rebound. However, the finally predominant'uppressure will leave the several assemblies in the relative positions of Fig. 24, for the pipe on its last upstroke will clear setter B and assembly C from gripping engagement therewith and weight 96 will become effective to raise both of them.

Fig. 25 illustrates the condition of elements when pulling the stem out by cable before the balance point is reached. Assemblies C and D are in release positiornsetter E is open, while setter B is closed and in condition to ratchet to allow the lifting of the pipe, though it will automatically set assembly C if the pipe starts to drop.- If the pipe breaks and the well pressure becomes efiective to eject the pipe, the operator need merely depress or drop handle 95 which will cause the setting of assembly D.

Fig. 26 illustrates the up-stroke of the yoke in the snubbing out operation. Assemblies C and D are held in neutral position, setter E is open (as in Fig, 19) and setter B may be closed or not, as the operator desires. Since yoke slips A are in work-gripping position, the upward movement of the pipe is controlled by regulation of the fluid pressure within cylinders iBS. Just before the yoke reaches the top of its strokathe operator closes setter E and holds downon cable 2M, thus holding ring 2635 and carrier T stationary while the yoke continues'upwardly, freeing slips [I23 from the pipe. As the end of the yokestroke is more nearly approached to increase the separation between flange Hat and ring 205, spring 2ii1,rotates latch 25d beneath flange ilBil to hold them separated and thus latch the yoke slips down in expanded or release position.

Since setter E has been closed it will have been eiiective, under theinfiuence, of the pipe as lifted by well-pressure, to set assembly D and thus hold the pipe from further upward movement after assembly A has been released, so, with the yoke slips latched down, (Fig. 27) the yoke may be lowered to take a new bite, whereupon cable Zia is pulled to swing latch 2H3 from holding position and thereby allow springs 206 to act to elevate carrier T and reset slips H93 on the pipe. Thereafter, clampE is re-opened and the snubbing out" cycle repeated.

. There are many other situations in which the equipment plays an important part, but it is believed the above illustrations will sufiice to point out the cooperation between elements and the general utility of the equipment. However, various changes in design, structure and arrangement may be made without departing from the spirit and scope of the appended claims.

We claim:

1. In combination, a supporting structure having an upwardly and inwardly tapering bore adapted to take a vertically extending pipe, a wedge slip assembly within the bore and movable upwardly therethrough from inoperative position into pipe-engaging position, a carrier for said assembly and engaging it from beneath, means for shifting said carrier vertically to move the assembly into pipe-engaging position, said means embodying a member applied to the pipe and to the carrier and adapted automatically to move said carrier and thereby the assembly upwardly upon initial upward movement of the pipe; 3. snubbing yoke mounted for vertical reciprocation above the supporting structure and having a bore adapted to take the pipe, and releasable pipe-gripping elements carried by the yoke.

2. In combination, a supporting structure having an upward and inwardly tapering bore adapted to take a vertically extending pipe, a wedge slip assembly within the bore and movable vertically therethrough into and out of pipe-en gaging position, a carrier for said assembly and engaging it from beneath, and means applied to said pipe and to said carrier and operable upon initial upward movement of the pipe to elevate said carrier and thereby move said assembly into pipe-engaging position.

3. In combination, a supporting structure having an upwardly and inwardly tapering bore adapted to take a vertically extending pipe, a wedge slip assembly within the bore and movable vertically therethrough into and out of pipe-engaging position, a carrier for said assembly and engaging it from beneath, manually operated means for shifting said carrier vertically,-and means applied to said pipe and to said carrier and operable independently of said manually operated means upon initial upward movement of the pipe to elevate said carrier and thereby move said assembly into pipe-engaging position.

4. In combination, a supporting structure having an upward and inwardly tapering bore adapted to take a vertically extending pipe, a wedge slip assembly within the bore and movable vertically therethrough into and out of pipeengaging position, a carrier for said assembly, and means applied to said pipe and to said carrier and operable upon initial upward movement of the pipe to elevate said carrier and thereby move said assembly into pipe-engaging position, said means embodying a tubular body member connected to the carrier and having a bore through which the pipe extends, said last named bore tapering upwardly and inwardly, and wedge slips in said body bore and about the pipe.

5. In a device of the character described, a

supporting structure having a bore whose upper portion tapers upwardly and outwardly and whose lower portion tapers downwardly and outwardly, a pair of wedge-slip assemblies complementary to and entered, one each, in said bore-portions, and a removable pipe-centering thimble supported by the structure between said assemblies.

6. In a device of the character described, a supporting structure having a bore whose upper portion tapers upwardly and outwardly and whose lower portion tapers downwardly and outwardly, a pair of wedge-slip assemblies complementary to and entered, one each, in said boreportions, and a removable pipe-centering thimble supported by the structure between said assemblies, said thimble embodying a parted ring, and means for spreading the ring-parts into a groove opening to said bore. q

7. A centering thimble embodying a parted ring, a pivotal connection between one set of opposed ring-ends, a wedge entered between the other set of ring ends, and means for urging the wedge between said ends to swing the ring parts about the pivotal connection.

8. In combination, a supporting structure having an upwardly and inwardly tapering bore adapted to take a vertically extending pipe, a suspension ring about the pipe above the bore, means for reciprocating said ring vertically along the pipe, suspension elements depending from the ring, and a wedge slip assembly within said bore and about the pipe, a second ring carried by said suspension elements and supporting said assembly, and a releasable pipe clamp carried by said second ring and engageable with said pipe, said clamp being adapted to move the assembly upwardly independently of the first ring, by virtue of initial upward movement of the pipe.

9. In a. device of the character described, a

supporting structure having a vertically tapering bore adapted to take a vertically extending pipe, 8.

tion as the first named bore, and wedge slips insaid body bore and about the pipe.

10. In adevice of the character described, a supporting structure having a vertically tapering bore adapted to take a vertically extending pipe, a wedge slip assembly within the bore and movable vertically therethrough in one direction from inoperative position into pipe-engaging position,

and releasable means applied to said pipe and said assembly and operable upon initial movement of the pipe in said one direction to move said assembly in said one direction, said means embodying a setter-body associated with said slip-assembly and having a bore through which the pipe extends, said last named bore tapering in the same direction as the first named bore, and wedge slips in said body bore and about the pipe.

11. In a device of the character described; a supporting structure having a vertically tapering bore adapted to take a vertically extending pipe, a wedge slip assembly within the bore and movable vertically therethrough in one direction from inoperative position into pipe-engaging position,

i and means applied to said pipe and said assembly and operable upon initial movement of the pipe in said one direction to move said assembly in,

ing bore adapted to take a vertically extending pipe, a wedge slip assembly within the bore and movable vertically therethrough in one direction from inoperative position into pipe-engaging position, and means applied to said pipe and said assembly and operable upon initial movement of the pipe in said one direction to move said assembly in said one direction, said means embodying a setter-body associated with said slip-assembly and having a bore through which the pipe extends, said last named bore tapering in the same direction as the first named bore, and wedge slips in said body bore and about the, pipe, said setter body being made up of a plurality of connected segments, and yieldable means for holding the segment-assembly constricted about the pipe.

13. In a device of the character described, a supporting structure having a vertically tapering bore adapted to take a vertically extending pipe,

a wedge slip assembly within the bore and mov ter body connected to the slip assembly in a manner to impart vertical movementthereto and capable of rotation with respect to the assembly, and pipe-engaging members carried by said body.

14. In a device of the character described, a supporting structure having an upward and inwardly tapering bore adapted to take a vertically extending pipe, a wedge slip assembly within the bore and movable vertically therethrough into and out of pipe engaging position, a carrier for said assembly, a suspension member for the carrier and extending upwardly to a point above said supporting structure, means for lifting the suspension member to move the slip assembly into operative position, said assembly being movable upwardly independently of the suspension member, and a slip setter below the slip assembly and engaged with the pipe, said setter being adapted to move said assembly upwardly upon initial upward movement of the pipe.

15. In a device of the character described, a supporting structure having an upward and inwardly tapering bore adapted to take a vertically extending pipe, a wedge slip assembly within the bore and movable vertically therethrough into and out of pipe engaging position, a carrier for said assembly, a suspension member for the carrier and extending upwardly to a 'point above said supporting structure, means for lifting the suspension member to move the slip assembly into operative position, and a slip setter below the slip assembly and engaged with the pipe, said setter being adapted to move said assembly upwardly upon initial upward movement of the pipe.

16. In combination, a supporting. structure having an upwardly and inwardly tapering bore adapted to take a vertically extending pipe, a Wedge slip assembly within the bore and movable upwardly therethrough from inoperative position into pipe-engaging position, a carrier for said assembly supported from above said assembly but engaging it from beneath, means for shifting said carrier vertically to move the assembly into pipeengaging position, said means embodying a member applied to the pipe and to the carrier and adapted automatically to move said carrier and thereby the assembly upwardly upon initial upward movement of the pipe; 9. snubbing yoke mounted for vertical reciprocation above the supporting structure and having a bore adapted to take the pipe, and releasable pipe-gripping elements carried by the yoke.

17. In combination, a supporting structure having an upward and inwardly tapering bore adapted to take a vertically extending pipe, a

wedge slip assembly within the bore and movable vertically therethrough into and out of pipeengaging position, a carrier for said assembly sup ported from above said assembly but engaging it from beneath, and means applied to said pipe and to said carrier and operable upon initial upward movement of the pipe to elevate said carrier and thereby move said assembly into pipe-engaging position.

18. In a device of the character.described, a supporting structure having a bore adapted to take vertically extending pipe therethrough, said bore having a portion tapering upwardly and outwardly and another portion tapering downwardly and outwardly, a pair .of wedge-slip assemblies complementary to and entered, one each, in said bore-portions, said assemblies being independently movable vertically through their respective bore-portions in opposite directions from inoperative position into pipe engaging positions,

and a slip-setter applied to one of said assemblies being operable upon initial movement of the pipe in one direction to move the associated assembly into' pipe engaging position without effectively moving the other assembly.

9. In a device of the character described, a supporting structure having a bore adapted to take vertically extending pipe therethrough, said bore having a portion tapering upwardly and outwardly and another' portion tapering downwardly and outwardly, a pair of wedge-slip assemblies complementary to and entered, one each, in said bore portions, said assemblies being independently movable vertically through their respective bore-portions in opposite directions from. inoperative positions into pipe-engaging positions, and a slip-setter applied to one of said assemblies and adapted to be applied to the pipe, said setter being operable upon initial movement of the pipe in one direction to move the associated assembly into pipe engaging position while the other assembly remains in pipeengaging position.

20.- In a device of the character described, a supporting structure having a bore adapted to take vertically extending pipe therethrough, said bore having a portion tapering upwardly and outwardly and another portion tapering downwardly and outwardly, a pair of wedge-slip assemblies complementary to and entered, oneeach, in said bore-portions, said assemblies being independently movable vertically through their respective bore-:portlons in opposite directions from inoperative positions into pipe-engaging positions, and a pair of slip setters adapted to be applied to said pipe and applied, one each, directly to said assemblies, one of said setters being operable upon initial movement of the pipe in one direction to move its associated assembly into pipe-engaging position, and the other setter being operable upon initial movement of the pipe in the opposite direction to move its associated assembly into pipe-engaging position.

'21. In a device ofthe character described, a

supporting structure having a bore adapted to take vertically extendlngpipe therethrough, said bore having a portion tapering upwardly and outwardly and another portion tapering downwardly and outwardly, a pair of wedge-slip assemblies complementary to and entered, one each, in said bore-portions, said assemblies being movable vertically through their respective bore-portions in opposite directions from inop erative positions into pipe-engaging positions, and a pair of independently releasable slip set ters adapted to be applied to said pipe and applied, one each, to said assemblies, one of said setters being operable upon initial movement of the pipe in one direction to move its associated ifig positions, a slip-setter applied to one of said assemblies and adapted to be applied to the pipe, said setter being operable upon initial movement of the pipe in one direction to move the" associated assembly into pipe engaging position, and means for moving the other assembly into and out of pipe engaging position without eifec tlvely moving said on'eassembly.

23. In combination," a supporting structure having an upwardly and inwardly tapering bore adapted to take a vertically extending pipe. a wedge-slip assembly within the .bore and movable upwardly therethrough from inoperative position into pipe-engaging position, manually operated means for movingsaid assembly upwardly, and a slip-setter 'operatively connected to the assembly and engageable with said pipe; said setter, when engaged with the pipe, being adapted automatically to move said assembly upwardly upon initial upward movement ot-the pipe without coincident efiective movement of said manually operated means.

24. In combination, a supporting structure having an upwardly and inwardly tapering bore adapted to take a vertically extending pipe. & wedge-slip assembly within the bore and movable upwardly therethrough from inoperative position into pipe-engaging position, manually options from inoperative positions into pipe-engagerated means for movingsaid assembly upwardly,

and a slip-setter' positioned below and operatively connected to the assembly and engageable with said pipe; said setter, when engaged with the pipe, being adapted automatically to move said assembly upwardly upon initial upward movement of -the pipe without coincident efiective movement of-said-manually operated means.

, 25. In a device of the character described, a supporting structure having a bore adapted to take vefiically extending pipe therethrough, said bore having a portion tapering upwardly and outwardly and another portion tapering downwardly and outwardly, a pair of wedge-slip assemblies complementary to and entered, one each, in said bore-portions, said assemblies being independently movable vertically through their respective bore-portions in opposite directions from inoperative positions into pipe-engaging positions, manually operated means for moving said assemblies vertically, and a slip-setter operatively connected to one of said assemblies and engageable with the pipe, said setter, when engaged with the pipe, being adapted automatically to-move said one assembly into pipe-engaging position without coincident\efi'ective movement of said manually operated means. I r FREDERICK STONE.

ALBERT L. STONE.

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