US2148844A - Packing head for oil wells - Google Patents

Description

Feb. v28, 1939. A. `I .vs'roNE ET AL 2,143,844

v v v PACKING HEAD FOR OIL WELLS l Filed Oct. 2, 1936 ."5 Sheets-'Sheet l v Feb. v.23, 1939.

A. sTvNE ET AL PACKING HEAD FOR OIL WELLS Filed oct. 2, 193e 3 Sheets-Sheet 2 Inventar; lrl l Stolze, FIWIIZ'JZ Sawyer.

A. l.. 'sToNE ET AL v PACKING HEAD FOR OIL WELLS Fehlzs, 1939. .y

s sheets-sheet Filed Oct. 2, 1936 /00 Iride/liar? .lbe'll 512226,

Patented Feb. 28, 1939 UNITED STAT ES;

PATENT OFFICE PACKING FR. OIL VVLLSl tion of California Application Octoberl 2,

8 Claims.

This invention has to do generally with` devices ffor sealing around work, e. g. drill pipe and the like, in` oil well drilling operations. In. certain of its aspects, the invention is directed to 5, improvements in packing heads of the type disclosed: in the. copending applications of Frederick Stone et al., on. Packing head, Serial Number 50,482, led November 19, 1935, now Patent No. 2,124,015, issued Julyv 19,v 1938, and Oil Well packlo: ing, heads, Serialf Number 97,632, filed August 24,

@ne ofl our principal objects is to alter and. simplify the type of packing head constituting the subject-matter ofy the copending applications rev,1 ferredf to,'for the purpose of better adapting the head to simpler and:` more economical manufacture, and to certain uses where all` the features of the earlier `disclosed inventions may not/be riequired. In accordance with the present invention', we, have provided an improved form of packing heady capable of general use for sealing around work of various types, shapesv and sizes, and possessing, notwithstanding its simplicity, the capability of controllable positive action that insures dependableY operation and prolonged service.

The invention also embodies another feature of outstanding: importance, that distinguishes it from all prior packing heads or similar devices of which wev are aware. We refer here to the utility of the invention asa stripper that may be used, for example, to. maintain by means of a single packer,v a fluid tighty seal about. elongated work having cross sectional enlargements, for example, collared pipe, as the Work is bei-ng pulled from "z or lowered into the well. Although the packing heads disclosed in tliev above mentioned copending applications also. have been` found to be capable of such operation as strippers, as Well as for sealing: about work that remains without great variation in its cross sectional size or area, the present forms. rif-packing heads are in general better adapted` to thaty type of operation. Different forms of strippers have been proposed, and vsomey are in common use,A but our improved de;- vice diiers from all these in that it involves a distinctly different. structure and mode of operation, particularly as 'regards the provision for rendering the packer expansible to pass the pipe collar, and yet capable of maintaining at all times an effective seal about the. pipe.

Referring particularly to its stripper aspect, thel invention may be described briefly as comprising an expansivepacker together with a movable packing contracter, preferablyv though not 55 necessarilyin the broaderaspects ofthe inven- 1936, Serial No. 103,678y

tion, a fluid pressure actuated piston, that yieldably bears against the packer to maintain it in radially constricted condition about the work. The coaction between the packer and. the contractor isl reciprocal in that the packer' is radially constricted by movement of the contractor, andthe latter-isr inturn displaceable ln response to expansion or movement of the 'packer'. Advantagev isV taken of this condition to adapt the device for use as a stripper, the contractor serves to maintain the packer constricted about the smaller diameter pipe, but enables the packer. to pass the pipe collar because when the packer is expanded by movement of a pipe collar into it, the contractor is 'accordingly displaced by the packer expansion, permitting the collar to pass through the packer. Thereafter, the contractor immediately closes. the packer about the smaller diameter pipe.

All the various features and objects will be more fully explained and understood to better advantage inthe following detailed description of the invention in certain of its typical and illustrative forms. Throughout the description reference is had to the accompanying drawings, in which:

Fig. 1` is a sectional view showing a typical form of invention, with the packer in expanded positiij' Fig. 2 is a View similar to Fig. 1 showing the packer constricted' about the work;

Fig. 3 is a sectional View' illustrating a variational form` of the invention;

Fig'.y 4 is a similar' view showing a modication of the form of Fig, 3; and

Figs. 5 and 6 show additional variant forms in which the packer contractor moves downward against the direction of well flow.

Referring ilrst to Fig. 1, the packing head generally indicated at I0 and mounted on the Well casing IIi, comprises a body I2 that may conveniently be made in two sections, the upper section Iii being threaded at I4 on the lower section I5, and the latter attached at I6 to the casing by a threadedconnection or in any other suitable manner.l Suitable packing I'I may be interposed between the body sections to prevent fluid leakage through the joint at I4. Upper body section I3 is shaped to provide an annular cylindric walled chamber I8 to receive the later described packer contracting piston, and has an inner tubular wall I 9 with downwardly tapering surfaces 20 and 2| at the upper and lower ends of the counterbore 22. The opening or bore 23 through the bottom inwardly flanged end 24 of the tubular wall I9 is of suicient diameter to pass the maximum diameters of the work 25, for example, pipe couplings 26, the drill bit (not shown), or other tools that may be carried in the pipe string. The lower body section I5 has a cylindric bore 21 within which the contractor piston works, and an lannular shoulder 28 at the bottom of the bore that serves as a stop to limit the downward travel of the piston.

The tubular packer contracting piston 29 com prises an upper enlarged diameter portion 29a having a substantially sliding fit with the body bore 30 and the outer cylindric surface lila, of wall I3, and a lower reduced diameter portion 29h slidably tting the wall of counter-bore 21 in the lower body section I5. The piston carries packing rings 32 to prevent fluid leakage along the piston from either chamber I8 or space 33, the lower section also containing packing rings 34 that prevent fluid leakage along the piston from yeither space 33 or chamber 35 within the head below the packer. The piston may be regarded as having three pressure areas: the up'- wardly facing surface 3B on the top of the p-iston exposed to 'chamber I8, the downwardly facing surface 31 formed on the piston intermediate its ends and exposed to space 33, and a pressure area generally indicated at 38, on the lower end of the piston, the last mentioned area corresponding to thearea lbetween the work 25 and the lower body section counter-bore 21. For reasons that will later appear, it'isdesirable, as isthe case, that pressure area 36 be greater thanv pressure area 38, in Vorder that the piston may be caused to move downward'by the application of the same fluidpressure per unit-arcate the two surfaces.

A suitable flexible packer 4I, preferably in the form of a continuously annular (as distinguished from segmental annular) rubber sleeve, is conflned between the inwardly projecting piston flange 40 and the lower end of the inner tubular portion I9 of the upper body section. Asillustrated, the packer has a straight rbore 42 with annular clearance in its expanded condition about the work 25, the outer diameter and shape of the packer being made to snugly fit the piston'bore 43 and the Vtop surface of ange 40. While either or both ends of the packer may be connected to the adjacent shouldered surfaces against which the packer ends bear, the packer is shown typically as being fastened to the bottom ofthe body flange 24. Our preferred form of packer connection comprises a fabric 44 embedded in the rubber' at the upper 'and'outer' interiorof the packer and clamped between `flange 24 and a ring 45 held tightly to the'ilange by screws 46. The bottom surface of the ring maybe provided with annular concentricridges 41 which'form grooves or recesses in'to which the rubber is forced upon longitudinal compression, and fromfwhich the air is thereby expelled, so that lthe'pressure applied to the packer also serves as a means of securely holding it to its support. The fabric 44 provides an effective and durable connection for anchoring the packer to the support, in that it is adapted to withstand 'the strains and distortions to which the packer is subjected in being constricted about the work, 'and in being forced tosome extent up through-the flange Ybore 23, when the packer is holding extremely high well 'pressuresl As illustrated in Fig. '2, upon upward movement of the `piston 29, packer 4Iy is constricted radially into'sealing engagement with the work due to longitudinal compression between stationary supporting nange 24 and theY interior piston flange 40. Where the apparatus is to be used for general purposes as a packing head or stripper it is desirab-le to limit the upward piston travel and therefore the extent of packer constriction about the work. For example, -to reduce wear on the packer when employed to seal about a drill pipe or a polygonal cross sectional kelly during drilling operations, it is desired 'to limit the packer contraction tov the point where a slight leakage of well fluid will be allowed through the packer to lubricate its engagement with the work. It is also desirable that piston limiting or stop means be adjustable and capable of regulation to compensate for wear on the packertending to enlarge its normal bore diameter.

In accordance with the invention we have provided an improved type of piston stop means in the form of adjustable screws 53 threaded at 5I into the piston and extending through .the top wall of the body, suitable packing 5I held in place by retaining ring 52 being provided tol prevent fluid leakagel past Athe screws. Each of the stop screws has a flange 53 that cornes into engagement with ring 52 to limit the upward travel of the piston as shown in Fig. 2, all the screws of course being. correspondingly adjusted to give flanges 53 the same spacing from the piston.

The contactor piston is operated by f fluid pressure, preferably gas or mixed gas and liquid, communicated selectively to chamber-I8 and space 33 by way of pipes 54 and 55. The piston operating uid may be derived from any suitable source, for example from. the well casing via line 56, or from an independent source through line 51. The communication of the pressure fluid to lines 54 vand 55 is controllable by affour-way valve diagrammatically shown at 51. With the valve positionedY as Vshownin Fig. 1, the operating uid pressure is communicated to chamber I8 and to the upper pressure area 3S of the-piston to maintain the latter in its lower position and the packer 4I in radially expanded condition. The pressure'in space 33 is released via pipe 55 communicating witlr the exhaust line 58. To constrict the vpacker about the` work, `the position of valve 51 is reversed, venting chamber I8 to the exhaust line, and communicating the pressure fluid to space Y33, the application of the fluid pressure to piston surface 31 causing the piston to move upward and to constrict the packer, as shown in Fig. 2. To again open the packer, valve 51 is returned to the position illustrated, and although the pressures then applied to piston areas 36 and 38 may be the same when the well pressure is employed to, operate the piston, the latter will move downward by reason of the differential in the areas as described above.

In normal drilling operations the packer may be maintained constricted about the Work, the drill pipe or polygonal cross sectional kelly, where the Well is under pressure. The head also may be used as a blow-out preventer to close about the work in the event of sudden development of high well pressures. Assuming the packer to be open, as in Fig. 1, and the well to suddenly develop high pressure, the packer may be immediately closed by communicating the pressure viiuid to space 33 to raise the contractor piston.

We have previously referred to the particular advantage of the invention in being capable of operation as a stripper capable of passing and maintaining a fluid tight seal about. successive lengths or stands Yof collared pipe being pulled from or lowered into the well. The adaptability of the head for use as a stripper results from the displaceability of the piston as a result of packerV expansion by the pipe collars, tov permit the collars to pass through'the. packer. Assuming that the pipe string is being pulled from the well with the packer closed about the pipe and a collar 26 raised tothe point Where it has enteredy the lower endof the packer as shown in Fig. 2, continued upward' movement of the collar tends to displace and to longitudinally expand the packer. The result is that the rubber tends to flow andthe lifting force on the collar to be transmitted through the rubber to the piston ange 40, causing the piston to be displaced downwardly a distance sufcient' to accommodate the volume of vrubber displaced' by the collar as it enters and moves through thev packer bore. Consequently, by reason oi' the displaceabi'lity of the piston by the packer, it has been found possible to pull the collar through the packer at any desired speed and Without excessive wear on the rubber or damage to the packer. `Displacement oi the piston is yieldably resisted by the fluid contained in space 33, the connecting lines and the chamber rbelow the piston (valve v51 being reversed from the positions of Fig. l) and as a result, the packer at all times. during this operation tightly engages the surfacev of the collar and immediately constricts about the smaller diameter pipe as the collar moves out: of the packer. As will be apparent, the same piston-action in response to expansion of the packer occurs as the pipe string is being lowered into the well.

While generallysimilar to the described form of the invention shown in Figs. 1 to 2, the variational Yform of Fig., 3 differs mainly with respect to thebody structure and its attachment to the casing, the packer mounting (the packer in this form being carried vby the piston), and the provision of a tapered body shoulder or bore cooperating withthe; piston to radially constrict the packer. rIn Fig. 3 the body 60 has a counter-bore 6| and a lower reduced diameter bore 62 containing the piston 63, the downward travel of the piston being limited by engagement with stop shoulderA 64,. with clearance providedI at 65 to receive the operating fluid introduced through line 55. Here the packer 66 is seated within the comparatively large diameter piston counter-bore 61, the. lower portion 63a and body bore 62 being of reduced diameter so that the piston pressure area 31 is somewhat larger than the corresponding area 31 in Fig. l, and the bottom pressure area 38 is comparatively smaller. Likewise, the differential between the top piston area 36' and the bottom pressure area 38', is comparatively greater than in the first described form.

The body is attached toA the casing by a type ofV joint 68 that may be broken without requiring rotation or substantial elevationr of the head, and permitting the head1 to be shifted laterally to one sidewhen the joint is disconnected. The lower end of the body has a tapered shoulder G9 that seats on the top correspondingly shaped surface of a sleeve T threaded at 'H on the casing.

Sleeve 12, threaded at 13 on the body and having bodily movable with the piston in its vertical travel. The connection between the packer and the piston is similar to the previously described form, and comprises a fabric 11 embedded in the outer interior of the packer and clamped between the annularly grooved ring 18 and the upwardly facing piston surface 1'9. As the piston is moved upwardly, the packer is radially constricted by movement along the tapered bore 80 of head 8l threaded at 82 into` the upper end of the body. In assembling the apparatus, the piston rst may be raised to insert the stop screws through openings 83k in head 8|, and the latter then screwed down to scat on shoulder 84, the piston and packer assembly rotating with the head as the latter is being threaded into the body.

The operation of the last described form of the invention is similar to the previously described form, as will be apparent without the necessity for repetitious description. It may be observed in passing, that the main difference in operation is the eifect of the tapered bore 8l) in causing radial contraction of the packer by inwardly displacing it as the piston moves upwardly. Also it may be observed that this form of head is capable of operation as a stripper in the manner previously described, since the piston and packer are reciprocally displaceable, i. e., each is displaced in response to movement of the other.

The second variational form of the invention shown in Fig. 4 diiers from that ofv Fig. 3 in that it is designedy to provide a somewhat simpler and less expensive head intended, though not necessarily limited, for use only as a blowout preventer. Here the piston stop screws are eliminated to simplify the construction and cheapen the cost of manufacture. This is permissible where the apparatus is to be used as a blow-out preventer (and the same applies to the previously described.

forms) since, although the provision of stop means for` limiting the full conti-active position of the piston may be desirable, such means may be dispensed with inv favor of cheaper construction adapted to the specific purpose. It will be noted that in Fig. 4, the samey type of connection at 68 is employed for attaching the body to the casing, a readily disconnectible joint of this type being desirable in order to enable the stripper head to be quickly applied to and removed from the casing. Fig. 4 illustrates an additional feature in the provision of an annular shoulder 85 at the upper end oi the tapered bore 30, and which is engaged` by the upper end of the packer so that the latter is confined between shoulder 85 and the pistou shoulder, and held against bodily upward movement as in the case of Fig. 3. As will be apparent, when the piston moves upward, the packer is radially constricted by longitudinal compression as in the form or" Fig. l, and is also subjected to inward displacement as the rubber is pressed against the tapered surface 80.

To further simplify the construction in this form, the pressure fluid connection with chamber i8 above the piston may be omitted, and merely a vent opening provided. at 88 or some other suitable location. In the absence of a pressure fluid connection for moving the piston downward. to open the packer, the latter may be'released from the work and the contractor returned to its lower position, by relieving the well pressure acting upwardly against the piston and packer. Thus, assuming a blow-outv to have occurred and the packer to have been closed by fluid pressure communicated through line to lspace 33, circulating mud may be pumped into thewell through cof the drill string to kill the' well, whereupon the pressure in space 33 may be released, permitting the packer to expand longitudinally and move the piston down.

Figs. 5 and 6 show additional variant forms of the invention similar in principle to the described embodiments, but differing primarily in the arrangement of thepiston so that it moves downwardly in constricting the packer, in opposition to the direction of pressure communication from the well, instead of moving upwardly with the well pressure, as in the rst described forms. InFig. 5, the packer 88 is contained within the inverted cup-shaped piston 89 that slidably engages the bore 90 of body section 9|, the packer being attached to the shouldered wall y89a by the previously described type of connection generally indicated at 92. The upper reduced diameter tubular portion 89h of the piston Vslidably ts bore 93 in the top wall of the body. The packer 88 is confined between the piston shoulder 89a. andthe stationary upper end 94a of the lower body section 94, so that as the piston is moved downwardly by pressure uid communicated to chamber 95, the rubber is longitudinally compressed and radiallycontracted between the shoulders 89a and 94a. If desired, a pressure iluid connection 96 may be provided for delivering operating fluid to chamber 9'| to raise the contractor and release the packer. The head is shown to be mounted on the casing by threading the lower body section 94 on the upper end of the casing.

In Fig. 6, the inverted piston 98 is extended upwardly through bore 99 in the top of the body |00, the top of the piston being exposed, with the packer |0| attached to its under surface at |02. Upon downward movement of the piston, the packer is pressed against the downwardly tapering stationary surface |03 of the lower body section |04, the piston being forced downwardly by uid pressure communicated to chamber |09. As in Fig. 5, the piston may be raised to release the packer by pressure iiuid introduced to chamber |06, or, in case the fluid connection |06a is not used, by relieving the well pressure in the manner previously explained and allowing the packer to expand to release itself from sealing engagement with the work.

We claim:

1. In a packing head applied to a well pipe, a tubular housing adapted to pass collared tubing through its bore, a packer in the housing and radially contractible about said tubing to prevent fluid escape from said pipe through the housing, a continuously annular packer contracter movable vertically within the housing and directly engaging the packer, one end of said packer being bodily and vertically movable with said co-ntractor in its contracting movement, a packer support, ilexible means embedded in the packer and attached to said support, and means for selectively introducing into fluid-tight spaces Within said housing and substantially closed from communication with said well pipe through the housing bore, uid under pressure to move the contracter'in opposite directions and thereby to cause the packer to radially expand and contract.

2. In a packing head applied to a well pipe, a tubular housing adapted to pass collared tubing through its bore, a continuously annular packer vthrough the housing, said packer having a longitudinally tapered portion, a continuously annular packer contracter movable vertically within the housing and directly engaging the packer, one end of said packer being bodily movable with said contracter in'its contracting movement, a packer support, exible means embedded in the packer and attached to saidV support, Wedge means engaging said tapered portion of the packer and acting to radially constrict the packer during packer contracting movement of said contracter, and means for selectively introducing into fluidtight spaces within said housing and substantially closed from communication with said well pipe through the housing bore, fluid under pressure to actuate the contractor and thereby to cause the packer-to radially expand and contract.

3. In a packing head applied to a well pipe, a tubular housing adapted to pass collared pipe through its bore, a packer in the housing and radially contractible about said tubing to prevent iiuid escape from said pipe through the housing, a continuously annular packer contracter movable vertically within theY housing and directly engaging and surrounding theY outside of the packer, one end of said packer being bodily movable with said contractor in its ,contracting movement, flexible means connecting said end of the packerv to the contracter, and means for introducing into a fluid-tight space within said housing and substantially closed from communication with said Well pipe through the housing bore, fluid under pressure to actuate the contracter.

4. In a packing head applied to a well pipe, a tubular housing adapted to pass collared tubing through its bore, a packer in the housing and radially contractible about said tubing to prevent fluid escape from said pipe through the housing, I

a continuously annular packer contracter movable vertically withinV the housing and directly engaging the packer, an annular. shoulder on said contracter supporting one end of said packer, said end of the packer being bodily Ymovable with the contracter in its contracting movement, supporting means stationary with relation tol the housing and supporting the opposite end of the packer, fabric embedded in the packer and projecting from the last mentioned end thereof, means connecting the fabric to said support, and means for selectively introducing into fluid-tight spaces within said housing and substantially closed from communication with said well pipe through the housing bore, fluid under pressure to move the contracter in opposite directions and therebyr to cause the packer to radially expand and contract.

5. In a well pipe packing head, a tubular housing adapted totake an elongated member through its bore, a radially contractibleV packer in the Vhousing and about said member, a'packer contracting piston movable vertically within the housing, one end ofsaid packer being suported. directly by and movable vertically with said piston in its contracting movement, fabric embedded in said end of the packer and connected to the piston, and a clamp ring securing said fabric to the piston.

6. In a well pipe packing head, a tubular housing adapted to take an elongatedv member through its bore, a radially contractible packer in the housingV and about said member, a packer contracting piston movable vertically within the housing, one end of said packer being supported directly by and movable vertically with said piston in its'contracting movement, and fabric em.- bedded in said end of the packer and connected to the piston. .f

7. In a packing head applied to a well pipe, a tubular housing adapted to pass collared tubing through its bore, a packer contracting piston movable vertically Within the housing and having differential pressure areas, an annular shoulder formed on and within said piston, a stationary annular shoulder spaced axially of the housing from said piston shoulder, a packer between said shoulders and surrounding the housing bore, flexible means embedded Within and extending beyond the end of the packer, means attaching said ilexible means to said stationary shoulder, the end of the packer adjacent the rst inentioned shoulder being bodily movable with the piston, valve means for selectively introducing into fluid-tight spaces Within said housing and substantially closed from communication with said well pipe through the housing bore, fluid under pressure acting against said differential piston areas to move the piston in opposite directions.

8. In a packing head applied to a Well pipe, a tubular housing adapted to pass oollared pipe through its bore, a packer contracting piston movable vertically within the housing, an annular shoulder formed on and Within said piston, a sta tionary shoulder spaced axially of the housing from said piston shoulder, a packer between said shoulders and surrounding the housing bore, fabric embedded Within the packer, means attaching said fabric to said stationary shoulder, means forming on said contracter oppositely facing differential area pressure surfaces intermediate its ends, and means for selectively introducing into' fluid-tight spaces Within said housing and substantially closed from communication with said well pipe through the housing bore, fluid under pressure acting against said dilerential area surfaces to move the contracter in opposite directions and thereby to cause the packer toY radially expand and contract, the end of the packer nearest said annular shoulder being bodily movable with the piston.

ALBERT L. STONE. FRANK R. SEAVER.

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