US1949498A - Pump-down plug - Google Patents

Description

March 6, 1934. F. STONE ET AL PUMP DOWN PLUG 2. Sheets-Sheet l 72 l 1279.12.

Original Filed July 6, 1951 March 6, 1934. F, STON Er AL 1,949,498

PUMP-DOWN PLUG Original Filed July 6, 1931 2 Sheets-Sheet 2 9 us. L E'ngsfromfx .fr/zeg Freo/@fida fmef Patented Mar. 6, 1934 UNITED STATES lPATENT OFFICE PUlVIP-DOWN PLUG Application July 6, 1931, Serial No.` 548,838 Renewed November 25, 1933 Claims.

This invention has to do generally with casing plugs used for closing off the vbores of well pipe, and is more particularly concerned with plugs of the pump-down type, adapted to be pumped down into well pipe against well pressure. Itis particularly well adaptable for use in plugging Well pipe having substantially flush, internal joints.

'I'here 'are various occasions which lead to the desire for or necessity of closing off the bores of well pipe casing, but since these occasions are well known to those skilled in the art, it will be unnecessary to enumerate them here. It will suice to say that such plugs must be of a nature to enable their sure and reasonably accurate setting and to establish a fluid tight barrier across the casing bore.' 1t is therefore the major object of our invention to provide a plug which answers well to these requirements.

- placement may be accurate, it is necessary that leakage ofthe pumpingfluid between the exterior of the plug and the casing walls be reduced to a minimum. We have therefore provided a packing, which we will term a plunger packing, t0

distinguish over the main packer which is expanded when the plug is set, about' the upper end of theplug. This plunger packing is so constructed and arranged that it insures a tight fit between the plug and casing as the plug is being lowered, thus minimizing leakage losses as faras possible. The piston packing'is capable of being adjustably expanded to a predetermined 4diameter prior to the entrance of the plug -to the casing, this diameter being somewhat larger than the inside diameter of the casing so a. snug fit will be insured as soon asthe vplug is introduced. The plunger packing also controls the downward passage of the plug under'certain conditions, and aids in effecting a `plugvsealuwhen the plug is finally set.

As a feature of great advantage, we have pro-y vided a radially expansible packer which, as the plug is being pumped down, remains in radially contracted or inoperative position to avoid undue wear against the casing wall-,and then, after the plugl has been set thrQughwedge slips by relieving the fluid pressure from above', the packer is radially expanded to operative position by a `spreader which is operated by fluid pressure from the slips are complementary to the associated way walls 15 with which they engage, while the outer below. The advantages of this feature will be readily understood by those skilled in the art.

During the descent of the plug the fluid pressure below acts against the packer-expander with a tendency to expand the packer into operative 00 position, but this tendency is overcome by the provision of a piston connected to the packer-expander, said piston being held depressed by the pumped-in fluid and thus holding the expander in an inoperative position until the pressure of 85 the pumped-in fluid is relieved.

We have also provided a novel tell-tale orindicator to keep the operator advised of the position ofthe'plug under certain circumstances.

Various other advantages and features of novelty of the invention will be made apparent in the following detailed description, reference b'eing had to the following drawings, in which:

' Figure 1 is a medial section through a plug embodying our invention, showing said plug within a casing. The plug is not here set, nor is the packer thereon expanded into close-off position; Fig. 2 is a view similar to Fig. 1 but showing the plug set and the packer expanded into closeoff position;

Fig. 3 is a section online 3-3 of Fig. 1;

' Fig. 4 is a section on line 4 4 of Fig. 1;

Fig. 5 is a section on line 5-5 of Figjl; and Fig. '6 is a longitudinally contracted section of a casing showing therein our improved plug with its attached indicator.

The numeral 10 indicates generally the body member of our improved packer 9. For ease of manufacture and assembly, this body member'is preferably made up of two parts 11 and 12 which are threadably connected at 13.

The upper end of body part 12 is provided with longitudinally extending ways 14 (preferably, although not necessarily, four in number and equal- 1y spaced apart as viewedin plan) thebottom 95 Walls 15 of these ways inclininginwardly and `upwardly to provide wedge faces which serve as backing for taking radially, inwardly directed thrust of wedge slips 16. The inner faces 17 of facesl of the slips are serrated as at 18 to'provide vertically` extending grlpping'teeth.

Ways 14 are under-cut at 19 to receive the slip wings 20 whereby the slips are held to wedge faces 105 15` throughout their longitudinal play through the ways. V-It will `be seen that f due to this slip mounting, relativelcngitudinalor vertical movement of the slips and body member causes said slips to move radially to and from radially extended positions. When the slips are at their uppermost limits, as determined by the downwardly facing shoulders 21 on body part 11, teeth 18 are preferably substantially flush with the peripheral face of the body member and, when they are moved toward their lowermost or expanded position, the teeth are projected radially beyond said peripheral face.

Considering the several slips together as a radially expansible and contractible gripping means, it will be seen that body member 10 may be considered, in part, as an upwardly pointing wedge which, by vertical movement with relation to the slips, causes radial expansion or contraction of the gripping means.

The upper end of body part 11 has a cylinder wall 21 which defines cylinder or chamber 22 and whose outside diameter is reduced with relation to the diameter of the main body member to provide an upwardly facing, annular shoulder 23, said shoulder preferably inclining inwardly and downwardly at 24 and terminating in a flat shoulder 25. Shoulders 24 and 25 may be considered as defining an annular groove 26 which is of angular cross-section definition.

Slipped over wall 21 is a resilient, annular plunger packer 27 of rubber or the like, the lower end 28 of this member being formed complementarily to and taken in groove 26. Threaded on wall 21 at a point 29 above packing 27, isan adjusting and retaining nut 30 provided with spanner wrench sockets 31. The under face 32 of this nut is grooved to present a downwardly and outwardly inclining annular shoulder 33 which terminates at its upper end in a flat shoulder 34. The upper end 35 of packing ring 27 is complementary to the downwardly facing shoulder of nut 30, being fitted in the groove defined by these shoulders. It will thus be seen that ring 27 is taken endwise between oppositely inclining shoulders on the body member and nut 21, the longitudinal overlap of these shoulders over the ends of the packing ring preventing said ends from outward radial displacement with respect to the body member. By adjusting nut 30 along thread 29, it will be seen that the packing ring may be placed under predetermined longitudinal or endwise compression which bows the ring outwardly by the consequent radial expansion. Nut 30 is adjusted to bow the packing ring so it extends radially beyond the peripheral face of the body member sufficiently to extend into tight peripheral engagement with the particular casing C which is to be plugged. To insure such engagement the packing ring is normally bowed outwardly to about the position indicated in dotted lines in Fig. 1, that is, to give it an initial oversize 'outside diameter.

Further to maintain a fluid tight seal between ring 27 and the casing, the packing ring preferably is provided about midway of its length with an upwardly pointing, annular lip 36 which defines the outside of a groove 37. Fluid pressure pumped into the casing-above the plug enters groove 37 and therefore exerts an effective pressure against the inside offlip 36 tending to expand said lip radially into tight engagement with the casing.

Preferably we reenforce ring 27 internally with rings of fabric or the like 38, the `reenforcement preferably being heavier at the ends of the rings than at the center, as illustrated, both to care for the radial and thrust strains imposed directly on these ends by the opposing shoulders 24 and 33 and to give the ring a natural tendency to bow outwardly when placed under longitudinal compression.

The lower end of body part 12 carries a reduced diameter and externally threaded portion 40, there thus being provided a downwardly facing, annular shoulder 41, this shoulder preferably inclining slightly inwardly and upwardly from the peripheral face of the body member. A radially expansible packer sleeve 42, of rubber or the like, has at its upper end an internal annular flange 43 which defines a bore 44 adapted to take portion 40. The upper end face 45 of packer 42 is complementary to and engages shoulder 41, said upper end and said flange preferably being reenforced as at 46 and 46'.

A cylindric nut 47 is threaded on extension 40 beneath flange 43, being introduced from the lower end of packer-bore 48. 'I'he upper end of nut 47 is preferably beveled off to provide an annular shoulder 49 which inclines oppositely from shoulder 45. Flange 43 is thus clamped between shoulders 41 and 49 to hold packer 40 from bodily longitudinal displacement with respect to body member 10 the opposite inclination of shoulders 41 and 49 holding the flanged end of the packer from being bodily expanded radially clear of the nut under endwise pressure of the latter.

Adapted to 'reciprocate vertically within cylinder chamber 22 is a piston head 50, preferably having fluid sealing grooves 51, its flange 52 being adapted to seat on the upper end of wall 21 to limitk downward movement of the piston head and its associated parts, thus maintaining the lower end or downwardly facing shoulder of the piston spaced above the end wall 22' of the cylinder. Depending from head 50 is piston rod 53, a lock washer 54 and nut 55 serving, with rod shoulder 56, to clamp the head and rod together.

Rod 53 extends downwardly through bore 57 of body part 11, bore 58 of body part 12 and projects to a point below the end of extension 40, where it terminates in a threaded stem 59.

The diameter of bores 57 and 58 are preferably such with relation to the diameter of rod 53 that there is annular clearance about said rod which provides a passageway along the rod from the bore 48 of packer 42 to cylinder or chamber 22.

Threaded on stem 59 is an upwardly pointing, hollow, spreader wedge or expander 60 which is in the general form of an erect, truncated cone or bell, the lower exterior end or nose of which is preferably rounded as at 61 to facilitate its passage through the casing and casing joints, the major external diameter of the expander being somewhat less than the inside diameter of the casing. Wedge 60 is thus suspended from body member 10 by head 50 and rod 53, head 50 centering and guiding the wedge during its vertical movement.

The nose 6l of the expander is centrally apertured as at 62, while ports 63 extend from the expander hollow 64 through expander hub 65, opening at their upper ends into the bore 48 of packer 42 at a point below extension 40. The lower end of packer 42 is provided with a conical counterbore 65' which is complementary to and tightly engages the inclined wall or wedge face 66 of the expander.

With the parts in the position of Fig. 1, the peripheral face of packer 42 is substantially flush with the peripheral face of body member- 10, but the packer is adapted to be expanded radially into fluid-tight contact with casing C in a manner now to be described.

It will be assumed the plug is to be pumped down through a casing C against pressure in that casing. As the plug is introduced to the casing the slips are checked by the end 'of the casing until the body member has dropped. sufficiently to draw the plug slips radially inward a distance suicient to clear them from the pipe, whereupon said slips pass downwardly with the body member, their teeth 18 sliding along the casing wall. Preferably the lower ends of the slips are angled inwardly and downwardly as at 67 to facilitate their entrance in the casing bore and their movement over internal casing shoulders or other obstructions in their paths.

As has been stated previously, plunger packing 27 will have been radially expanded into tight peripheral engagement with the casing. Fluid is then pumped into the casing bore above the plug to force it downwardly, piston head 50 closing the upper end of the plug bore and taking the pressure of the pumped fluid to hold the expander depressed or in inoperative position against the tendency of the fluid below to lift the expander into operative or packer-expanding position. Packer 42 is thus kept clear of the casing throughout its downward movement, to obvious advantage.

Plungerring 27 closes the annular space between plug and casing to insure, with piston 50, thatall fluid introduced to the casing is effective in forcing down the plug. Leakage thus being avoided, a careful measurement of the uid pumped into the casing will, by proper computa-` tions, keep the operator advised as to the exact position of the plug with respect to the top of the casing.

The fluid pressure applied from above is, of course, so maintained that it overpowers the casing pressure below the plug. When` the amount of fluid pumped in on top the plug issufcient to depress the p lug to the desired point in the casing, pressure from above is ,relieved and the pressure belowr the plug acts on the body member to lift it suiciently to cause wedge action between 4faces 15 and 17 which, since the slips 16 are` alreadyv in engagement with the casing, radially expands the slips and drives teeth 18 into ,gripping engagement with the casing walls. The

wardly and thuswedge it into the packer 42, thisl action tending to expand the `packer radially into tight engagement with said casing wall for it will be seen that the casing uidunder pressure from below passes upwardly through port 62, hollow 64, ports 63 and bores 58 and;57 around rod 53 into chamber 22 where it acts on the lower end of piston head 50 to raise, through :rod.53, expander 60 into said packer-expandingor operative position. The upwardly ,directed iiuid pressure is also imposed against the lower end 61 of expander 60 downwardly facing shoulder'k 66"`presented by the under-face of expander-hub 65, v

Since the fluid 'cannot pass upwardly beyond the lower'endof head"`50,'due to `the piston-like lit of this head-with vthe cylinder wa1l 21, the plug now'makes a barrier across the entire bore of casing C, isolating the portion of the casing bore above the plug from the portion which lies below said plug. Plunger packing 27 aids, of course, in maintaining the uid seal between the body member 10 and the casing.

It will thus be seen that we have provided a plug which is adapted to be pumped down to a predetermined position with the packer-expander held in inoperative position, and then, after the plug has been slip-set in that position, a mere release of pumping pressure allows the well pressure from below to set and maintain the expansible packer in' a condition to plug oil? the casing.

Head 50, rod 53 and spreader wedge 60 may be considered together as an expander, said expander having an upwardly facing shoulder (the top of piston 50) exposed to downwardlyA directed fluid pressure, and downwardly presented shoulders 61, 66 and 50 exposed to fluid pressure in the casing bore below the plug; the expander being raised into packer-spreading position by virtue of the iiuid pressure exerted against these latter faces after the pressure on the upwardly facing shoulder is relieved.

In Fig. 6 we have illustrated a novel form of indicator `or tell-tale. This indicator includes a float 70 of any suitable material attached by light cable 7l to piston rod 53 (and hence to plug 9) as by threading it through transverse opening 72. The length of cable 71 is greater than the length of the shortest stand of casing C. A stand of casing represents the linear extent of casing between the particular couplings which are made or broken in going into or coming out of the hole. Usually, though not necessarily, a stand is made up of two or more lengths of coupled casing, which lengths are handled as a single unit in going into or coming out of the hole, it therefore being only necessary to make or break the couplings between stands, rather than between individual casing' lengths, during such operations. For example, say stand 73, made up of two casing lengths 73' and 73", is the shortest stand in the casing string, then cable 71 is longer than this stand. The string is broken only at the stand ljoints 74, 75, the intermediate length-joints in a given stand remaining made-up.

Float 70, which may be considered the free upper end of the indicator, maintains cable 71 stretched to its full length. Now if when pulling the casing andbreaking stand-joint 74, oat 70 appears in sight, the operator knows the plug 9 is near the upper end of stand 76 and pumps the plug down. He is thus able to keep the plug depressed to a position where it will not be accidently removed along with any stand being disconnected, it being realized that such accidental removal would open the casing top and result in a loss of the control of well pressure.

While we have shown and described only a single embodiment of our invention, it will be. understood that various changes in design, structure, and arrangement, may be made without departing from the spirit and scope of the appended claims.

We claim:

1. A plug for casing, embodying a tubular body member, a tubular, radially expansible packer on the body memberya piston slidable vertically in and closing ol the body member bore near its upper end and above the packer, an upwardly w the body member bore and connecting the wedge and piston, there being passageways through the lwedge and body member from the exterior of the plug below the packer to the underside of said piston, and the upper side of said piston being exposed to fluid pressure in the casing above the plug.

2. A plug for casing, embodying a tubular body member, a tubular, radially expansible packer on the body member, a piston slidable vertically in and closing off the body member bore near its upper end and above the packer, an upwardly pointing, hollow spreader wedge enteredin the bore of the packer, there being an opening through the wedge wall from the outside of the plug to the wedge hollow, and a piston rod extending through the body member bore and connecting the wedge and piston, there being passageways through the wedge and body member from the wedge hollow to the underside of the piston.

3. A plug for casing, embodying a tubular body member, a tubular, radially expansible packer depending from the body member, a downwardly facing shoulder on the body member and engaging the top of the packer to hold itv against upward bodily longitudinal displacement along the body member, a piston slidable vertically in and closing oi the body member bore near its upper end and above the packer, an upwardly pointing spreader wedge entered in the bore of the packer, and a piston rod extending through the body member bore and connecting the wedge and piston, there being passageways through the wedge and body member from the exterior of the plug below the packer to the underside of said piston, and the upper side of said piston being exposed to fluid pressure in the casing above the plug.

4. A plug for casing, embodying a tubular body member, a tubular radially expansible packer on the body member, a piston slidable vertically in and closing ofi the body member bore near its upper end and above the packer, an upwardly pointing spreader wedge entered in the bore of the packer, and a piston rod extending through the body member bore and connecting the wedge and piston, the top of said piston being exposed to casing pressure above the plug.

5. A pump-down plug for casing and embodying a body member, a radially expansible packer carried by said member, an expander carried by said body member and movable upwardly into packer-expanding position, a piston carried by and movable vertically with respect to the body member, means connecting the piston and expander, said piston having its upper end exposed to pressure within the casing above the plug to hold said expander in inoperative position while the plug is being pumped down, and slips having longitudinally extending, wedge face engagement with said body member whereby upward movement of the body member with relation to the slips moves said' slips radially outward.

6. A pump-down plug for casing and embodying a body member, a radially expansible packer carried by said membenan expander carried by said body member and movable upwardly into packer-expanding position, said expander having a downwardly disposed pressure-taking face exposed to pressure within the casing below the plug, the expander being movable upwardly into packer-expanding position by virtue of such pressure applied to said race, and a packing ring around the body member at a point above the packer.

7. A pump-down plug for casing and embody- 75 ing a body member, a radially expansible packer carried by said member, an expander carried by said body member and movable upwardly into packer-expanding position, said expander having a downwardly disposed pressure-taking face exposed to pressure within the casing below the plug, the expander being movable upwardly into packer-expanding position by virtue of such pressure applied to saidl face, a radially expansible packing ring around the body member at a point above the packer, and means for expanding the packing ring radially prior to insertion of the plug in the casing.

8. A pump-down plug for casing and embodying a body member, a radially expansible packer carried by said member, an expander carried by said body member and movable upwardly into packer-expanding position, said expander having a downwardly disposed pressure-taking face exposed to pressure within the casing below the plug, the expander being movable upwardly into packer-expanding position by virtue of such pressure applied to said face, a radially expansible packing ring around the body member at a point above the packer, and means for exerting endwise pressure on the packing ring thereby to expand it radially.

9. A pump-down plug for casing and embodying a body member, a radially expansible packer carried by said member, an expander carried by said body member and movable upwardly into packer-expanding position, said expander having a downwardly disposed pressure-taking face exposed to pressure within the casing below the plug, the expander being movable upwardly into packer-expanding position by virtue of such pressure applied to said face, a radially expansible packing ring around the body member at a point above the packer, and a nut threaded on the body member and engaging one end of the packing ring whereby to exert regulated endwise pressure on 115 the ring and thereby expand it radially and selectively.

10. A pump-down plug for casing and embodying a body member, a radially expansible packer carried by said member, an expander carried by 120 said body member and movable upwardly into packer-expanding position, said expander having a downwardly disposed pressure-taking face exposed to pressure within the casing below the plug, the expander being movable upwardly into packer-expanding position by virtue of such pressure applied to said face, slips having longitudinally extending, wedge face engagement with said body member whereby upward movement of the body membervwith relation to the slips moves saidl 130 slips radially outward, and an annular packing ring around the body member at a point/above the packer.

l1. A pump-down plug for casing and embodying a body member, a radially expansible packer carried by said member, an expander carried by said body member and movable vupwardly into packer-expanding position, said expander having a downwardly disposed pressure-taking face exposed to pressure within the casing below the plug, the expander being movable upwardly into packer-expanding position by virtue of such pressure applied to said face,slips having longitudinally extending, wedge face engagement with said body member whereby upward movement of the body member with relation to the slips moves said slips radially outward, a radially expansible packing ring around the body member at a point above the packer, and means on the body member for radially expanding said packing ring. l5() 12. A casing plug embodying a body member, a tubular, radially expansible packer on the member, a piston freely slidable vertically in a bore provided in the body member, an upwardly pointing spreader wedge in the bore of the packer, said piston and'wedge being connected for movement one by the other, and casing-gripping means on said body member. 13. A pump-down plug for casing made up of a plurality of disconnectible stands, said plug embodying a body member, a radially expansible packer carried by said member, an expander carried by said body member and movable upwardly into packer-expanding position, said expander having a downwardly disposed pressure-taking face exposed to pressure within the casing below the plug, the expander being movable upwardly into packer-expanding position by virtue of such pressure applied to said face; and a position indicator attached to said plug extending upwardly from said plug, said indicator having a yfree upper end and being of a length greater than the length of a given stand.

l 14. A pump-down plug for casing made up of a plurality of disconnectible stands, said plug embodying a body member,.a radially expansible packerr carried by said member, an expander carried by said body member and movable upwardly intc'packer-expa'nding position," saidexpander havinga downwardly disposed pressuretaking face exposed to pressure within the casing below the plug, the expander being movable upwardly in'to packer-expanding position by virtue of such pressure applied to y:said face; a cable extending from the upper end of the plug, and

a iloat applied to said cable.

15. In combination, a plug adapted to be depressed through a casing made up of a, plurality of disconnectible lengths; a cable extending from `the upper end of the plug, and a float applied having a downwardly disposed pressure-taking face exposed to such uid pressurewithin the casing below the plug, the expander being movable upwardly into packer-expanding position by virtue of such pressure applied to lsaid face.

17. A plug 'adapted to be set within a casing or the like against upwardly directed fluid pressure therein, said plug embodying a body member, a tubular, radially expansble packer, a member applied to the upper end of the packer and to the lower end of the body member to secure one to the other, an expander carried by said body member and movable upwardly with respect thereto and through the bore of the packer into packer-expanding position, said expander having a downwardly disposed pressure-taking face exposed to such fluid pressure within the casing below the plug, the expander being movable upwardly into packer-expanding position by virtue of such pressure applied to said face,and an upwardly facing shoulderV on said expander and exposed to iluid pressure from above the plug.

.18. A casing plug embodying a body member, a tubular, radially expansible packer on the member, a piston freely slidable vertically in a bore provided in the body member, means limiting the downward movement of the piston, and an upwardly pointing spreader wedge in the bore of the packer, said piston and wecme being connected for movement one by the other.

19. A casing plug embodying a body member, a tubular radially expansible packer on the member, a piston freely slidable vertically in a bore provided in the body member, and an upwardly pointing spreader wedge in the bore of the packer, said piston and wedge being `connected for movement one bythe other.

20. A plug for casing embodying a tubular body member, a radially expansible packer on the member, a piston slidable vertically in and closing off the body member bore above the packer, a packer expander below the packer and movable upwardly with respect to the body member into packer-expanding position, and a piston rod extending through thebody member bore and connecting the expander and piston, the under side of said piston being exposed to iiuid pressure in the casing below the plug, and the upper side of said piston being exposed to fluid pressure in the casing above the plug. f

` FREDERICK STONE.

RUFUS L. ENGSTROM.

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