US1971514A - Casing plug - Google Patents

Description

2 Sheets-Sheet l Invenfar. Frederme v i :Efiarneg F. STONE CASING PLUG,

Filed July 6, 1931 Aug. 28, 1934.

Patented Aug. 28, 1934 CASING PLUG Frederick same, Los Angeles, Calii'., assignor, by

mesne assignments, to Hydril Company, Loo

Angeies, Calii., acorporation oi California Application July 6, 1931, Serial No. 548,837

13 Claim.

This invention relates generally to plugs for oil well casings and the like, and is more particularly concerned with plugs of the mechanically set type, though not limited thereto in all aspects.

The occasions for plugging of theboresof well pipe casing and the like are well known to those skilled in the art and it will therefore be unnecessary to discuss them here. It will sufilce to say that such occasions do arise, and it frequently occurs that the situation is such as requires a most accurate placement oi. a plug at a predetermined location in the well casing.

Most plugs are of the pump-down type, that is, the plug, by itself, is and then pumped down to approximately the proper position by measuring in a predetermined quantity of pumping fluid. Due to unavoidable leakage of this fluid around the plug and due to the difllculty of measuring with great accuracy the exact amount of fluid used to depress the plug, it is practically impossible to secure the degr'ee of accuracy in plug placement required in certain situations.

It is therefore among the objects of my invention to provide a plug which is mechanically lowered by drill stem, or the like, so, by the easy and accurate method of recording the length of the lowering string as it enters the hole, the operator may know at all times exactly where the plug is with reference to the hole depth and then set the plug when it exactlyreaches the predetermined location.

The plug carries a radially expansible packer which is adapted to be in radially contracted position as the plug is lowered, thus avoiding wear of and damage to the packer as it is passed down through thecasing and past the shoulders presented by the casing joints. when the plug is at the desired location, the packer is radially expanded into fluid tight engagement with, the easing by a spreading mandrel which is controlled from the top of the well through manipulation of the tools by which the plug has been lowered.

It is also an object o! my invention to provide described having a bore arr-.11 mun Astheplmhtoaerve'aaatullharrlel'torflle mmitiimeellarzotmto'dnleol it this time!!! mwmfleflnkletat dropped into the casing.

the predetermined location. Therefore I provide a valve for this passageway, the valve being positively held open during 'descension of the plug, and being released for movement to close off the passageway while the plug is being set. As a so convenience, the same manipulation of the drill stem which accomplishes packer expansion is utilized to eiiect the release of this valve, but it will berealized the provision of this single member as a dual control element is not controlling on the broader aspects of the invention.

After usual plugs have served their purpose as barriers, it is customary to'remove them from the casing by pushing them downwardly and out the open end of the easing into the hole below, the lower end of the casing normally being spaced above the hole bottom; downwardpressure'being applied to the plug either by pumping fluid into the casing or by lowering a string or pipe thereagainst. The plug, then lying in the bottom of the hole, is broken up and drilled out by the subsequently descending boring tool.

After my plug has served its purpose, it may be disposed of as mentioned above, means being provided whereby the packer may first be contracted. The contracting and depressing tool maybeinthenatureofcasingwhichistobeset within the outercasing, in which case the packer precedes it as a guide or shoe. There is such connection between the plug and depressingtool that the plug is maintained connected to and in erect position when it is pushed out the bottom of the outer casing, thus preventingthe plug from being cocked across e open hole and interiering with the final tting ofthe inner casing- However, it is sometimes desirable to retrieve the plug, either for the purpose oi! re-use or for avoiding its presence in the hole bottom. It is therefore a further object of the invention to provide means whereby-the plug may be retrieved I irom the top of the casing, the retriever preterably being of such a nature that it may be manipulated to allow radial contraction of the packer sleeve before the plug is withdrawn, this action not only facilitating the withdrawal of the plug but also the packer by relieving it of peripheral contact with the casing wall.

Other features at novelty and advantages oi! theinvenfionwillhemadeapparentinthe-Iol lowing detailed deacrirflnn. reference being bad to the drawings, in which:

Hg. 1 is an elevatln o! a plug my =1sam msmmma y no Fig. 3 is a view similar to Fig. 2 but showing the plug set within a casing, the parts of the plug having been moved to positions expanding the packer into peripheral engagement with the casing, and the central valve having been moved to closed position;

Fig. 4 is a plan view of Fig. 3, with the casing omitted; i

Fig; 5 is a section on line 5-5 of Fig. 2;

Fig. 6 is a side elevation of a retrieving member used under certain circumstances in connection with the plug;

Fig. '7 is a bottom plan view of Fig. 6;

Fig. 8 is a section on line 8-8 of Fig. 6; and

Fig.- 9 is a fragmentary, reduced elevation, partly in broken away section, of the plug in the condition of Fig. 3, showing additionally the application of the retrieving member.

Referring particularly to Fig. 2, I have shown a tubular body member 10 having the general characteristics of an upright, truncated cone. The lower end of body member 10 is provided with two vertically spaced, annular flanges 11 and 12, the body member being further provided with a bore 13 and a counterbore l4.

Sunk in the conical face of body member 10,

are vertically extending ways 15, these Ways being undercut as at 16' (Fig. 5) there preferably being four such ways which are spaced equally apart about the cone. The bottom walls 16 of the ways recline in parallelism with the face of the cone and serve as backing or wedge faces for wedge slips 17 which are adapted to play longitudinally through ways 15. The outer faces of slips 17 are serrated as at 18, the serrated faces extending vertically while the inner wedge faces, 19 incline complementarily to way-walls 16. Slips 1'7 are provided with side wings or keys 20 which are taken within undercuts 16, the slips thus being held against radial displacement with respect to body member 10.

It will be apparent that relative vertical movement of the slips and body member 10, which may also be termed a slips carrier,causes radial movement of the slips, and considering the several slips together as a radially expansible and contractible gripp means, it will be seen that body member 10 may be considered as an upwardly pointing'wedge which, by vertical movement with relation to the slips, causes radial expansion or contraction of the gripping means.

I have shown springs arranged at the top and bottom of each slip, but the particularities of the spring mounting and the purposes of the s rings may be made apparent to'betteradvanta e at a later point in the discussio Supported within body member 10 is a twopart tubular mandrel 21 made upof a packerexpanding part or spreader 22'and a valve carrying part and spreader actuator 23, these parts being arranged for relative vertical telescopic movement, as will be made apparent.

At the upper end of mandrel part 23 is a horizontal, annular flange 24 which extends radially beyond the upper end of body member 10, the under face 25 of the flange engaging the upper end of body member. 10 and serving to limit the upward movement of slips 17 to prevent their accidental displacement from ways 15. Extending upwardly from flange 24 are ribs 26 which may be described generally as annular, though they are interrupted at diametrically opposite points to provide upwardly opening slots 27 (Figs. 1, 3 and 4). -At opposite sides of slots 27 the ribs areconnected by walls 28 and 29, Wells 28 inclining inwardly and downwardly and the opposing walls 29 being stepped or undercut to provide projections 30 having vertical faces 31 and downwardly presented shoulders 32.- The purpose of slots 2'7 will be considered later.

The upper mandrel-part 23 has rotative sliding fit in body-meinber bore 13, while the shank 33 of mandrel-part 22 has longitudinal sliding fit in counterbore 14, it being later made apparent that said shank is normally frictionally held against rotation. Mandrel-part 23 has a depending tubular extension 34 which is provided with external, right hand threads 35 adapted to be threadedly taken within the threaded bore 36 of mandrelpart 22, this'threaded connection between parts 90 22 and 23 serving to support the former from the latter and to provide means whereby the two parts may be given relative telescopic movement in the direction of their common axis.

The lower end 37 of mandrel-part 22 is given the external characteristics of an upwardly pointing wedge which has at its base a guiding nose 37', preferably of semi spherical characteristics. Ports 38 extend through the walls of the nose and of the wedge faces to allow fluid passage from the casing bore to the bore of hollow wedge portion 37.

Encircling mandrel part 22, preferably both about its upper cylindrical shank portion and its lower wedge portion, is an annular packer 39 which is in the form of a radially expansible and contractible sleeve of rubber or the like. The bore of packer sleeve 39 is substantially complementary to the parts of,.the mandrel about which it fits, while it is of substantially uniform outside diameter, except that it may be relieved as at 40 to facilitate its downward passage through the well pipe and joints thereof. As a protection to and guide for the lower end of packer 39, and generally as a guide for the plug, I have provided spring fingers 41 which are anchored at their lower ends to nose 37' and extend freely at their upper ends into longitudinally overlappingrelationship with packer sleeve 39.

The normal outside diameter of packer 39, with 120 the plug in the condition of Fig. 2 (in which case the packer may be considered as in radially contracted conditipn) is such that it will pass freely through the casing to which it is adapted. Interposed between the upper end of the packer 39 and flange 12 is a ring 42 made of relatively hard packing material, said ring being of slightly greater outside diameter than the packer 39 when the latter is radially contracted. Ring 42 serves to protect the upper end of the packing ring but will not be damaged nor will it cause damage if it engages the casing wall during descension of the plug. Fingers 41 and ring 42 may thus be considered as guiding or centering means at opposite ends of the packer which hold said packer annularly spaced from the casing wall during descension and ascension of the plug.

With mandrel parts 22 and 23 in the position shown in Fig. 2,it will be seen that packer 39.is held against longitudinal displacement along mandrel 21 by reason of its being clamped between the external wedge face 38' of part 22 and flange 12 of body member 10. On the other hand, mandrel 21, taken as a whole, is held against longitudinal movement with respect to body member 10 by reason of the fact that flange 24 and packer 39 engage opposite ends of the body member.

One or more vertical 'pins or keys 43 extend through ring 42 and into registering bores provided in the lower end of body member 10 and the 150 upper end of the stem carries a guide spider 56 which is adapted to seat on shoulder 50. Stem. 53 is adapted to slide through spider 55, while a compression spring 5''! encircles stem 53 and is interposed between spiders 55 and 56. This spring exerts an upward force on spider 56 and thus tends to urge rodpr stem 53 upwardly to seat head 54 on shoulder 52 and thus close the bore of mandrel part 23 and hence of the plug, proper.

Bore 45 has an internal, lefthand thread. A controlling sub 58 is connected to the lower end of a drill stem 59, or other suitable lowering and controlling tool. Normally, a string of hollow drill-rods is used for this purpose, and the joints of said rods are made up with right-hand threads. Sub 58 has a through bore 60 whichcommunicates with the bore 61 of drill stem 59, the sub also being provided with transverse ports 62 which open from bore 60' to the exterior of the sub for the relief of pressure raised within the bore of the plug during the lowering thereof.

Any suitable check valve 61' is provided in stem 59 fairly close to sub .58 to prevent fluid from passing upwardly through the stem bore from the plug bore- 7 Sub 58 has a downwardly facing annular shoulder 63, finished to seat tightly on the upper face 64 of mandrel-part 23, a reduced cylindric portion 65 adapted tightly to fit in bore 44, and an axially extending connector and valve-depressor 66 which is externally provided with left-hand threads adapted to fit tightly within the complementary threaded bore 45.

In preparing the plug for setting, sub 58 is screwed tightly home as in Fig. 2 to provide a tight frictional grip between it and body member 10 and and also to depress spider 56 against the action of spring 5'7 and thus maintain valve head 54 unseated to provide a clear passageway. through the plug from a point below packer 39 to a point thereabove. when the plug is subsequently lowered, fluid standing in or rising through the casing bore beneath the plug is then free to pass into the mandrel bore through ports 38 whence it passes into sub bore 60 from which it escapes through ports 62 to the casing bore at a point above the plug. This release of pressure greatly facilitates the lowering of the plug, as will be readily understood.

As I have stated at the forepart of the specification, it is sometimes desirable that the plug be retrieved. When such is the desire, slips 1'7 are supported in a manner now to be described. However, it is to be distinctly borne in mind that the plug so far described can be used to great advantage whether or not it be retrievable. When'it is not desired to retrieve the plug the particular slip support now to be described may be dispensed with/ Accordingly, the following description of a particular slip support is not to beconstruedasin anyway inferring thatthis is "upper end of'paclrer39. Keys 43 thus serve to essential to broader aspect.

Extending longitudinally of'body member 19 and through flange 11 is a bore 6'1 provided opposite each slip ((Flgs. 2 and 5). Each bore extends in parallel relationship with the outer face of the body member but is spaced radially inward slightly therefrom, a slot 68 opening from the bore to the periphery of the body member. A compression spring 69 is introduced to the bottom of'bore 6'7 through a clearance hole '70 in flange 12, the spring being held from subsequent downward displacement by a screw plug '71. Extending transversely through slip 1'7 is a screw pin '72 which projects through slot 68 into bore 6'7 in the path of spring 69. The tendency of spring 69 therefore is to lift slip 1'7 and by moving it upwardly along the wedge face of body member 10 to cause its movement radially inwardly toward the axis of the plug to contracted position.

, with the mandrel and the body in the relative positions of Fig. 2, compression springs '73 are interposed between each slip and the underface 25 of flange 24. The lower end of each spring is loosely seated in a socket '74, while the upper end '75 is brought through an opening in flange 24 and bent over the top of this flange as clearly indicated in Fig. 2. Springs '73 have such characteristics that they overpower springs 69 and consequently depress the slips with relation to body member 10 to maintain said slips yieldably in radially expanded position.

With the plugin the condition of Fig. 2, drill stem or casing 59 is lowered to depress said plug through casing C. As the lower ends of the slips (which are preferably beveled as at '76 to facilitate their entrance to and downward passage through the casing) engage the upper ends of the casing they are drawn inwardly due to the relative downward movement of body member 10 (springs '73 yielding to allow this movement) until they are drawn in sufficiently to enter the casing whereupon they travel downwardly with the descending plug but are constantly urged into sliding engagement with the casing wall by springs- '73.

when a suillcient length of drill stem has been measured into the pipe to lower the plug to the predetermined position, a slight pull on the drill stem draws the wedge faces 16 of body member 10 upwardly along slip faces 19 to cause radial expansive movement of the slips, thus engaging 'slip teeth 18 tightly with the pipe or casing, it being remembered that they have been up to this time, slidingly held in contact with said casing by springs '73. With the slips thus set in the easing wall, body member 10.is held against rotational and vertical movement with respect to the casing.

Drill stem 59 and consequently sub 58 are then rotated in a right-hand direction, the frictiontight fit between the sub and mandrel-part 23,

the invention. considered initsmentioned above, initially preventing the break ing of the left hand threaded joint between said sub and mandrel part. Due to this frictional set up. right hand rotation of sub 58 rotates mandrelpart 23 to the right with respect to mandrel space part 22. The latter is frictionallygripped, to prevent its rotation, by packer39which is anchored to body member 10 by keys 43, it being remembered that body member 10 is anchored against rotation by reason of the engagement 'of slips 1'7 with the casing wall. Thus, right-hand rotation of mandrel-part 23 with respect to mandrel-part 22, causes mandrel-part 22 toact as a nut and move upwardly along threads 35. In other words, mandrel- parts 23 and 22 are given relative vertical telescopic movement.

Since slips 17 are likewise holding body 10 against upward movement through the casing, flange 12 serves as a stationary shoulder or abutment to prevent the upward movement of packing sleeve 39. Consequently, the upward movement of the wedge orexpanding portion 37 of mandrel-part 23 acts through the bore of sleeve 39 to spread the latter radially into tight peripheral engagement with the inner wall of casing C, as indicated in Fig. 3. This expansion of sleeve 39 provides a fluid-tight seal between the plug and the casing.

During the initial rotation of mandrel-part 23, the upper ends of springs 73 are pulled out of line and their lower ends are dragged from socket 74. They thus become ineffective further to depress slips 17 and are usually broken off at a point adj acent flange 24 during continued rotation of member 23. The springs thus being disposed of, there is no longer any opposition, from above, to the action of springs 69. Said springs 69 cannot act, of course, at this time to lift the slips since said slips are tightly engaged with the casing, but during the retrieving operation, as soon as the .slips have been' freed from the casing, springs 69 serve to move the slips upwardly and thus into contracted position, as will be described.

The frictional set-up of sub 58 and mandrelpart 23 is such that this longitudinal movement of the spreading mandrel continues until the desired radial expansion of packer 39 has. been effected. 'I'hereupon the resistance to longitudinal movement of mandrel part 22 becomessufliciently great to hold mandrel part 23 from rota.-. tion, whereupon additional right-hand rotation of sub 58 through stem 59 breaks the left-hand threaded joint between the sub and mandrel part 23, whereupon the sub is continued in rotation until it is entirely cleared from the mandrel and the drill stem is lifted away.

As the depresser or extension 66 of sub 58 moves upwardly through bore 45, spring 5'7 acts on spider 56 to close valve 54, and with the bore of the plug thus closed by head 54, and the annular space between the mandrel and casing closed by the expan'sion packer 39, it will be seen that the plug provides a complete closure for the bore of the pipe. Of course, the upwardly acting fluid pressure on valve head 54 results in seating it more tightly and, in fact, spring 57 may be considered as assisting such pressure inseating the valve.

It will be noted that the length of the threaded connection between bore 45 and depresser. 66 is considerably greater than the extent of movement of valve 54 from 0 en to closed position. Hence, the valve is fully closed before sub 58 is completely unscrewed from actuator 23, giving the operator an opportunity, before he has disconnected the lowering tool from the plug, to allow pressure to build up below the plug and thus determine whether or not the plug is properly anchored and is effecting a proper seal. In other words, since the plug may be expanded and the valve closed ,while the lowering tool is still in supporting connection with the plug (though partially unscrewed therefrom) the operator retains controlover the plug, so if the test be unsuccessful (which may be' due to the location of the plug in a zone of damaged or defective casing) he can close the valve, contract the packer, shift the plug to a new position, and reset the plug and valve, all to obvious advantage.

when the plug has served its purpose, it may be disposed of either by thrusting it downwardly through the casing into the open bore below,

,or by lifting it through the casing. In the first cerned. It is then only necessary to overcome the frictional grip of packer 39 with the casing wall in order to push the plug out. I

However, it is sometimes preferable that packer 39 be contracted before the packer is pushed out, in which case the following operation is carried through. In this case the lowering stem is usually in the form of a casing which is to be set within outer casing C.

Attached to casing string the joints of which are connected by left-hand threads, is a retrieving sub 80, as shownin Figs. 6, 7, 8 and 9. This sub is connected by left hand threads 81 to the end of the drill stem, and is preferably made of relatively frangible material such as cast iron, for a purpose to be described. It consists of a hollow body portion 82 of cylindrical characteristics, a conical portion 83, and a depending, central pin extension or pilot nose.,84. Extension 84 may have a bore 85 in communication with hollow 82, the bore 85 being closed off if desired, by a removable plug 86. Extending downwardly from body portion 82 are diametrically opposite wings 87 which carry upwardly facing hooks 88 at their lower ends. The rear face of each hook is angled at 89' to be substantially complementary to the angle of walls 28 on member 23, while the hooks are so proportioned that they will enter slots 27 from above. Then, when the sub is turned in a left-hand direction, hook noses 90 are projected beneath shoulders 32. Also on the rear face of each hook member is provided a curved spring 91.

In making a connection between sub 80 and member 23, the drill stem is lowered until the underfaces of hooks 88 ride on the upper faces of ribs 26 and is then rotated untilthe noses drop into slots 27 and noses 90 are projected beneath shoulders 32. Springs 91, acting against the inof a length to depress spider 56 when the sub is lowered into connection, thus opening valve 54 to allow pressure from below the plug to be relieved through the -.plug bore and transverse sub ports 81'.

The assembly is'now in the condition of Fig. 9 and continued left-hand rotation of the stem brings the-forward faces 92 of wings 87 against shoulders 31 and sets up left-hand rotation of mandrel-part 23. Since mandrel part 22 is still held from rotation with respect'to the casing by the frictional grip of sleeve 39 (also remembering that sleeve 39 is additionally held from rotation by reason of keys 43 which connect it to the anchored body member 10) this relative rotation of parts 22 and 23 causes their relative longitudinal extensive movement along threads 35, mandrel 22 thus moving downwardly to allow packer 39 to contract radially by virtue of its inherent resilience. With the packerv 39 thus substantially cleared from the casing wall, a slight downward Jar on the drill stem imparted to body member 10 trees the slips from the cesium whereupon, in the event springs 69 and 73'are used, springs 69 act to urge said slips upwardly and hence radially inwardly to contracted position. It springs I 69 and 73 are not in place, this downward jar trees the slips from the casing sufllciently to permit subsequent lowering of the plug.

The casing 80' is then lowered to force the plug down, the plug then acting as a guide or landing shoe. When the plug is pushed out the bottom of easing C into the open hole below, hooks 88 maintain the plug suspended from string 80',

springs 91 insuring a continued hook-engagement, so said plug may be lowered in erect condition and will not become cocked across the hole bore to interfere with proper landing of the casing, as is apt to be the case where a loose plug is pushed out the casing bottom. A drill may be subsequentlylowered through the bore of stem 80' to drill out frangible sub 80 and the underlying p a In case it is desired to retrieve the plug, stem. 80' and sub 80 are manipulated as above to cause contraction of packer 39 and free slips 1'7 from the casing C. A continued upward pull on stem 80' acts through sub 80, due to the hookengagement beneath theshoulder 32, to lift the plug from the casing, whereupon it may be again prepared for use.

In the event there is no predetermined desire for retrieving the plug and it is merely intended to push it out through the open bottom of the casing after it has served its useful life, springs 69 and '73 may be omitted. In this case the slips tend to drop by gravity to expanded position, it being unnecessary to provide springs 23 since there is no upward force acting on the slips, due to the absence of springs 69. The setting operation will be exactly the same as that previously described. Without. the springs in place, it is of course impossible to retrieve the plug since there is nothing to move the slips to contracted position once they are freed from the, pipe and an upward pull on the drill stem would therefore cause immediate reengagement oi the slips with the casing.

While I have illustrated and described a preferred embodiment of my invention, it will be understood that various changes in the design,

structure and arrangement may be made without departing from the spirit and scope or the appended claims.

I claim:

1. A casing plug through a casing bore to a predetermined point therein, a wedge slip on the plug and movable longitudinally and radially with respect thereto into and out of gripping engagement with the casing, a spring acting on the slip and adapted to urge said slip out oi" gripping engagement, a second spring overpowering saidfirst mentioned spring and urging said slip into gripping engagement to a position holding the plug from subsequent upward movement from said point, and means for rendering said second mentioned spring ineffective whereby said first mentioned spring is subsequently effective to move said slip out of gripping engagement; a radially expansible, annular packer on said plug, said packer being in radially contracted condition and annularly clear 01 the casing while the plug is being lowered, and means for radially expanding said adapted to be depressed packer into peripheral engagement with the easlngnzlvhen said packer is at said predetermined m 0 2. In a casing plug adapted'to be depressed through a casing bore to a predetermined point therein, a wedge 'slip on the plug and movable longitudinally and radially with respect thereto into and out oigrippingengagement with the casing, a spring acting on the slip and adapted to urge said slip out of gripping engagement, a second spring overpowering said first mentioned spring andvurging said slip into gripping engagement to a position holding the plug from subsequent upward movement from said point, and means for rendering said second mentioned spring inefiective whereby said first mentioned spring is subsequently effective to move said slip out of gripping engagement.

3. A casing plug adapted to bedepressed through acasing bore to a predetermined point therein, a. wedge slip on the plug and movable' longitudinally and radially with respect thereto into and out of gripping engagement with the casing, a spring acting on the slip and adapted to urge said slip out of gripping engagement, a second spring overpowering said first mentioned spring and urging said slip into gripping engagement to a position holding the plug from subsequent upward movement from said point, a radially expansible, annular packer on said plug, said packer being in radially contracted condition and annularly clear of the casing while the plug is beinglowered, and means for radially expanding said packer into peripheral engagement with the casing when said packer is at said predetermined point, said last mentioned means being initially operable to render said second mentioned spring ineffective whereby said first mentioned spring is subsequently effective to move said slip out of gripping engagement. 4. Ina casing plug adapted to be depressed through a casing bore to'a predetermined point Y therein, a wedge slip on the plug and movable longitudinally and radially with respect thereto into and out orgr pping n m n with the casing, a spring acting on the slip and adapted to urge said slip out oi? gripping engagement, a second spring overpowering said first mentioned spring and urging said slip into gripping engagement to a position holding the plug from subsequent upward movement from said point, and rotatable means for rendering said second mentioned spring inefieetive whereby said first men'- tioned spring issubsequently eflective to move said slip out of gripping engagement.

5. In combination, a casing plug, a lowering tool disconnectibly applied to the plug for lowering it through a casing bore to a predetermined point therein, said plug embodying a body member, slips on the body member adapted to engage the casing at said point and thereby hold the body member against rotation within the casing, a radially expansible packer associated with said body member, said packer being in radiallwcontracted condition while the plug is being lowered, a packer expander associated with the packer and movable axially thereof into and out of packer expanding position, said expander being non-rotative with respect to the'body member when the packer is in contracted condi- 'tion, an actuator rotatably carried by the body member, means on the actuator adapted, upon rotation of the actuator, in a given direction, to coact with the expander in a manner moving said expander into packer-expanding position;

and a break-joint initially directly connecting said lowering tool to said actuator and initially holding them against relative rotation whereby initial rotation of said tool rotates 'said actuator and thereby moves said expander into position to expand the packer into tight peripheral engagement with the casing, whereupon the actuator is held against further rotation with respect to the body, a continuation of tool rotation thereafter breaking said joint and disconnecting the tool from the plug.

6. In combination a casing plug, a lowering tool disconnectibly applied to the plug for lowering it through a casing bore to a predetermined point therein, said plug embodying a body member, slips on the body member adapted to engage the casing at said point and thereby hold the body member against rotation within the casing, a radially expansible packer associated with said body member, said packer being in radially contracted condition while the plug is being lowered, a packer expander associated with the packer and movable axially thereof into and out of packer expanding position, said expander being nonrotative with respect to the body member when the packer is in contracted condition, an actuator rotatably carried by the body member, a righthand thread connection between the actuator and expander whereby right-hand rotation of the actuator moves said expander into packer-expanding position, and a frictionally set-up lefthand thread connection between the lowering tool and actuator, all in a manner whereby initial right hand hand rotation of said tool-moves said expander into position to expand the packer into tight peripheral engagement with the easing, whereupon the actuator is held against further rotation with respect to the body, a continued right-hand rotation of the tool breaking said left-hand thread connection and disconnecting the tool from the actuator.

7. In combination, a casing plug, a lowering tool disconnectibly applied to the plug for lowering it through a casing bore to a predetermined point therein, said plug embodying a body mem ber, slips on the body member adapted to engage the casing at said point and thereby hold the body member against rotation within the casing, a radially. expansible packer associated with said body member, said packer being in radially contracted condition while the plug is being lowered, a packer expander associated with the packer and movable axially thereof into and out of packer expanding position, said expander being nonrotative with respect to the body member when the packer is in contracted condition, an actuator rotatably carried by the body member, means on the actuator adapted upon rotation of the actuator, in a given direction, to coact with the expander in a manner moving said expander in'to packer-expanding position; said plug having an internal passageway opening at its lower end to the outside of the plug below the packer and at its upper end to the exterior of the plug above the packer, a valve in said passageway, said lowering tool coacting with said valve to hold it open while the plug is being lowered; and a break-joint,

initially directly connecting said lowering tool to said actuator and initially holding them against relative rotation whereby initial rotation of said tool rotates the actuator and thereby moves said expander into position to expand the packer into tight peripheral engagement with the casing, whereupon the actuator is held against further rotation with respect to the body, a continuation of tool rotation thereafter breaking said joint, freeing said valve for movement to closed position and finally disconnecting the tool from the plug.

8. In combination, a casing plug, a lowering tool disconnectibly applied to the plug for lowering it through a casing bore to a predetermined point therein, said plug embodying a body mem-- ber, slips on the body member adapted to engage the casing at said point and thereby hold the body member against rotation within the casing, a radially expansible packer associated with said body member, said packer being in radially contracted condition while the plug is being lowered, a packer expander associated with the packer and movable axially thereof into and out of packer expanding position, said expander being nonrotative with respect to the body member when the packer is in' contracted condition, an actuator rotatably carried by the body member, means on the actuator adapted, upon rotation of the actuator, in a given direction,to coact with the expander in a manner moving said expander into packer-expanding position; said plug having an internal passageway opening at its lower end to the outside of the plug below the packer and at its upper end to the exterior of the plug above the packer, a valve in said passageway, said lowering tool coacting with said valve to hold it open while the plug is being lowered, and means connecting the lowering tool to the actuator and adapted initially to hold them against relative rotation whereby rotation of said tool rotates the actuator and thereby moves the expander into position to expand the packer into peripheral tight engagement with the casing, whereupon the actuator is held against further rotation with respect to the body, a continuation of tool rotation setting up relative rotation between said tool and. actuator and thereby relieving the tool from coaction with the valve to free said valve for movement to closed position.

9. In combination, a casing plug, a lowering tool disconnectibly applied to the plug for supporting it and lowering it through a casing bore to a predetermined point therein, said plug embodying a body member, anannular packer associated with said plug adapted to have peripheral engagement with the casing, said plug havingan internal passageway opening at its lower end to the outside of the plug below the packer and at its upper end to the exterior of the plug above the packer, and a movable closure for said passageway, said closure being initially out of closing position and being movable into closing position while said tool is in supporting connection with said plug.

10. In combination, a casing plug, a lowering tool disconnectibly applied to the plug for supporting it and lowering, it through a casing bore to a predetermined point therein, said plug embodying a body member, an annular packer associated with said plug adapted to have peripheral engagement with the casing, said plug having an internal passageway opening at its lower endto the outside of the plug below the packer and at its upper end to the exterior of the plug above the packer, and a movable closure for said passageway, said closure being movable intoand out 01' closing position while said tool is in supporting connection with said plug.

11. In combination, a hollow casing plug having openings from the hollow portion to opposite ends of the plug, a valve seat and valve in the plug and cooperating to control fluid-flow through the plug hollow, a tubular lowering tool screw- 150 threadably connected to the plug with its bore in communication with the plug-hollow, said tool being normally screwed into the plug to a given position with relation thereto, and a member on said lowering tool cooperating with said valve, when said tool is in said position, to hold the valve from the seat, said valve being movable toward said seat when the lowering tool is unscrewed from said position.

12. In combination, a hollow casing plug having openings from the hollow portion to opposite ends of the plug a valve seat in the plug, a valve movable axially of the plug to and from a position engaging the seat to control fluid-flow through the plug hollow, a tubular lowering tool,-

a screw-thread connection between said tool and the plug, the bore of the tool being in communication with the plug-holiow a, member on said tool cooperating with the valve, when the-tool is screwed'home in the plug, to hold said valve a predetermined distance from said seat, the ef- Iective length of said screw thread connection being appreciably greater than said distance. whereby said valve is movable toward said seat as unscrewing movement is imparted to the tool and said valve is movable into contact with the seat before said tool is entirely unscrewed from the plug. 1

13. A casing plug adapted to be lowered through a-casing bore to a predetermined point therein, said plug embodying a body member, slips on the body member adapted to engage the casing at said point and thereby hold the body against rotation within the casing, a radially expansible packer associated with the body member, said packer being in radially contracted condition while the plug is being lowered, a key connection between said packer and body member to hold them against relative rotation when said packer is in readily contracted condition, a packer expander associated with the packer and movable axially thereof into and out of packer-expanding position, said packer, in its contracted condition, being adapted to hold the expander against rotation with respect thereto; an actuator rotatably carried by the body member, and means on the actuator adapted, upon rotation of the actuator, in a given direction, to coact with the expander in a manner moving said expander into packerexpanding position.

FREDERICK STONE.

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