US2651371A - Apparatus for plugging wells - Google Patents

Description

Sept. 8, 1953 L. W. TOELKE APPARATUS FOR PLUGGING WELLS 3 Sheets-Sheet l v Filed Sept. 27, 1948 FIG. 4

IN V EN TOR. L .W. TOELKE FIG. I

ATTORNEY Sept. 8, 1953 w. TOELKE APPARATUS FOR PLUGGING WELLS 3 Sheets-Sheet 3 Filed Sept. 27, 1948 p J W M 6 (I I mm Hv lfi m w L P 1| iii... Mk 1, 4 j, A 3 N F ATTORNEY the plug material beyond Patented Sept. 8, 1953 UNITED STATES PATENT OFFICE APPARATUS FOR PLUGGING WELLS Lester W. Toelke, Houston, Tex. Application September 27, 1948, Serial No. 51,350

6 Claims.

my copending application Serial No. 12,523, filed March 2, 1948, for Plugging Wells.

In the said copending application the method t "erein disclosed, generally stated, comprised inserting a hollow metallic plug into a well pipe, and applying fluid pressure internally of the plug to effect expansion thereof into plugging engagement with the pipe wall. The magnitude of the fluid pressure applied was Method and Apparatus for its elastic limit so that the plug became permanently deformed and set in its expanded condition. The explosion ofa charge of a suitable chemical explosive within the plug was employed fluid pressure, in accordance with one embodiment disclosed in said co-pending application. Another embodiment employed hydraulic pressure to accomplish the desired degree of expanin each embodiment .expansion of the plug was effected by the apsion of the plug. Thus,

plication of fluid terior of the plug.

The improvements contemplated by the present invention employ the previously disclosed principle of expansion of the plug beyond the elastic limit of the material of which it is conpressure directly upon the instructed to thereby effect permanent deformation and set the plug in its expanded condition. However, in accordance with the present invention, the application of fluid pressure is indirect, in that the fluid pressure is applied to drive a mandrel into expanding contact with the walls of the plug to thereby accomplish the same end result'as that contemplated by the earlier 'application. In accordance with the present invention, the requisite fluid pressure is preferably generated by explosion of a chemical explosive charge and is employed to actuate a piston carrying the expanding wedge or mandrel to drive the latter into expansive relationship with the plug. The various objects and advantages of the present invention will become apparent from the following detailed description when read in conjunction with the accompanying drawings which illustrate several useful embodiments in accordance with this invention.

'In the drawings:

Figs. 1 and 1A comprise a longitudinal generally sectional view showing the expanding deof an order to expand 5 to develop the requisite characteristics 2 vice and plug in accordance with one embodiment of this invention inserted in a well pipe preparatory to plugging the same;

Figs. 2 and 2A comprise a view similar to Fig. 1 showing the positions of the parts at completion of the plugging operation;

Figs. 3 and 3A comprise another view similar to Fig. 1 showing the parts of the device at a later stage of operation; and

Figs. 4, 5 and 6 are views showing additional embodiments of the plug after setting.

Referring to Fig. 1, the plug comprises a generally cylindrical metallic body ID, the external diameter of which is normally somewhat less than the internal diameter of a well pipe P in which the plug is to be set so that the plug may be readily insertible through the bore of the pipe. The metallic materials employed for the construction of the plug may be any metallic material possessing a sufficient degree of ductility or plasticity such that when subjected to the requisite expansive pressure, the walls thereof will expand to the desired extent without rupture or cracking and will become permanently set in their expanded condition. Many metals and their alloys possess these characteristics, some of the more useful examples of which are aluminum and magnesium and their various alloys, copper and its alloys including various brasses and bronzes, mild steels, etc. Generally speaking, the metallic materials will be employed in their non-heat-treated form which are generally softer and have greater ductility and plasticity than their heat-treated forms. It will also be found more generally desirable to employ metals having a relatively wide spread between their elastic limits and their ultimate strengths, this spread, of course, being to some extent a measure of the ductility or elongation of the particular metal. Ordinarily, metallic materials capable of elongation of 15 percent or more in two inches, as deterfound to be preferable, although materials of lesser elongation characteristics may be used in particular cases. Generally speaking, the type and character of the metallic material selected in any instance will normally depend upon the particular conditions to be met, such as the degree of expansion required, the pressures to be withstood by the seal, etc.

Body I 8 is provided with an axial bore 1 l which tapers inwardly and downwardly from the upper end thereof toward the lower end which is closed. Adjacent its lower end bore H is reend of piston rod 16.

duced somewhat in diameter to provide a shoulder l2 and to form an axially straight portion [3 below shoulder l2. A passageway [4 extends raidially through the wall of body above shoulder i2 and is adapted to provide communication between bore H and the exterior of body It). A spring-loaded check valve [5 of conventional design is installed in passageway M and arranged to open only in the outward direction, that is, for the discharge of fluid from bore 1 l to the exterior oi the body. A piston rod 16 extends axially into bore H and is provided adjacent its inner end with an enlargement 11 adapted to seat on shoulder 12 and a straight end portion 18 adapted to be slidably inserted in straight por- A plurality of radially arranged shear pins 19 extend through the wall of body ill into locking engagement with end portion It of the piston rod. Piston rod l6" has slidably mounted on an intermediate portion thereof a conical wedge or mandrel 20 which is downwardly and inwardly tapered to complement the slope of bore H but which is of larger base diameter than the upper end of bore ll, so that when the mandrel is driven downwardly into bore H it will effect radial expansion of the walls thereof. Mandrel 20' will normally be constructed of metal which is harder than that of body in. The lower end of mandrel 20 normally extends part-way into bore H and a compressible packing ring 2!, such as a conventional O-ring, is arranged circumferentially between the adjacent surfaces of bore H and mandrel 20 to form a fluid-tight seal therebetween. Piston rod 46 extends into a cylinder 22 through an end wall 23 and sealing rings 24 and 25 are arranged between the cylindrical surface of piston rod l6 and the adjacent surfaces of mandrel 20 and end wall 23, respectively. The end of piston rod 16 extending into the bore of cylinder 22 carries a piston 26 by means of which piston rod I6 is reciprocated in a manner to be described hereinafter. Piston 26 is removably mounted on the end of piston rod it by means of threads 26a and is provided in its upper face with wrench sockets 261) by which the piston may be screwed on-or off the rod. Piston 26 is preferably dimensioned so that a small amount of annular clearance will be provided between the periphery of the piston and the bore of cylinder 22. An annular shoulder 21 is provided at an intermediate portion of the bore of cylinder 22 to limit the extent of downward movement of the piston and thereby provide an explosion chamber 28 between the lower end face of the piston and end wall 23 of the cylinder. The upper end of piston rod i6 is provided with a narrow axial bore 29 extending to a point below the lower face of piston 26, where it is intersected by a plurality of radial passageways 30 providing communication between bore 29 and the interior 0! explosion chamber 28. The upper end of cylinder 22 is provided with a threaded socket 3! adapted to receive the threaded end of a connection member 32, commonly termed in the art a rope socket, to which is connected a cable 33 through which is threaded an electrical conductor 34 which extend through a suitablebore 35 in the rope socket to the lower end thereof where it is conne'cted to a conventional electrically-fired detonating fuze 35, which is directed toward the interior of cylinder 22 and arranged in' general axial alignment with bore 29 in the It will be understood that cable 33 and conductor 34 extend to the surface the bore.

4 at the top of the well and that conductor 33 will be connected to a suitable source of electric current, such as a battery (not shown) by means of a conventional initiating circuit (not shown) for firing fuze 36.

A charge 31 of a suitable chemical explosive is placed in explosion chamber 28 for actuating the expanding device in the manner to be hereinafter described. Charge 3-1 may consist of any of the well known chemical explosive substances including the various detonating and defiagrating types. The detonating type explosives may be exemplified by trinitrotoluene, pentaerythritol tetranitrate, Pentolite, Amytol, Cyclonitel Tetryl, Tetrytol, and the like. The deflagrating types include the various smokeless nitrocellulose base explosives and the various black powders. These explosives may be employed in granular, plastic, or molded and compressed pelletized form. The pressure generating characteristics of all such explosives are well understood and readily determinable for each particular case. It will be understood that the quantity of explosive used will depend in general upon the particular explosive material and the pressures to be developed in each particular case.

I'he apparatus may be assembled in the following manner: Piston rod IE will be inserted into bore H of the plug body and straight portion of the rod seated in straight portion [3 of Shear pins 19 will then be inserted through the wall ofbody [0 to lock the plug to the end of the piston rod. Mandrel 20 will then be slipped over the end of the piston rod and inserted into the upper end of bore H to whatever distance may be permitted by the relative normal dimensions of these parts. The upper end piston rod I6 will then be slipped through the opening in end wall 23 of cylinder 22. Explosive charge 31 will be inserted into chamber 28 about piston rod 16, and piston 26 will then be screwed into the end of the piston rod.

With this arrangement it will be seen that plug body It! will be suspended from piston rod l6 which is, in turn, suspended from piston 26 by the engagement of the latter with shoulder 21. Rope socket 32 is then inserted in the upper end of cylinder 22 and the device is thus assembled preparatory to running into pipe P.

The method of plugging a well in accordance with this invention, using the above-described apparatus, may be performed as follows: Charge 31 of the selected explosive material in the predetermined quantity to generate the desired pressure will have been introduced into chamber 28 in the manner previously described and the device assembled as noted. The device will then be lowered on cable 33 into pipe P to the poiht'at which it is desired to set the plug. Initiating current will then be transmitted through conductor 34 to set-on fuse 36. The explosion of the latter will act in the conventional manner to send a high pressure, high temperature blast or flame through bore 29 and passageways 30 into chamber 28 where the blast will set-off charge 31. The resulting explosion of the latter will practically instantaneously generate a high pressure body of gases which, being confined within chamber 28, will act in all directions, driving pisten 26 upwardly and cylinder 22 downwardly. The upward movement of piston 26 will tend to pull body it) over mandrel 20 while the opposite movement of cylinder 22 will tend to drive'ni'andrel downwardly into the bore ofthe body. "I'he resultant of'both actions will beto forcibly drive the mandreldownwardly. into bore II and expand the walls of body I0 outwardly into tight downward-movement of the mandrel. Due tothe conical shape of the mandrel, the expansive pressure thereof on the wall of body will be substantially uniformly distributed circumferentially of the body so that a tight circumferential seal will be effected between body l0 and the wall of pipe P. As noted previously, the quantity and character of the explosive material selected will be predetermined to develop pressure exerted through mandrel 20 to apply an expansive form on the wall of body In such as to exceed the elastic limit of the material of which body I0 is constructed but which will not attain the rupture strength of the body. Under such a force, the wall of body 0 will be permanently deformed and become permanently set in its expanded position so that a tight seal with pipe P will be maintained even after mandrel 20 is withdrawn from the bore of body l0.

Shear pins l9 will be designed to withstand the force driving mandrel 20 into body H) but will be at least partially sheared, as indicated in Fig. 2A. Thereafter, by applying a jerk or sharp pull on cable 33, shearing of the pins l9 may be completed. An upward pull on cable 33 will then draw piston rod I6 upwardly through mandrel 20 until enlargement strikes the lower end of the mandrel (see Fig. 3). Engagement of enlargement I! with the mandrel will cause the latter to be pulled upwardly and out 'of the bore of the plug, whereupon the plugsetting structure may be withdrawn from the Well, as illustrated in Fig. 3.

By the method and device in accordance with this invention, it will be seen that plugs of the character described may be set very quickly and in very tight engagement with the pipe. Due to the relative softness and ductility of the plug metal, the expansive pressure will extrude the metal into pits, cracks or crevices in the pipe wall which serves to increase the efliciency of the seal and to lock the plug to the pipe wall.

Figs. 4, 5 and 6 illustrate alternative embodiments of the form of the plug element showing, in each case, the plug in position in pipe P after expansion in the manner previously described. In Fig. 4 the upper portion of the exterior of body I0 is provided with .a. circumferential compressible sealing ring 40, which may be constructed of rubber or rubber like composition, and a plurality of circumferentially arranged toothed slip segments 4|. Upon expansion of body ID in the manner previously described, sealing ring 4|) will be compressed tightly between the plug and the pipe to assure additional sealing efficiency, while slips 4| will be driven into gripping engagement with the pipe wall to prevent displacement of the plug in the pipe. In Fig. 5 only the compressible sealing ring 40 is employed, while in Fig. 6 only the toothed slips 4| are employed. In each case, the principal plugging seal is formed by the permanent deformation of body In in compression against the pipe wall, while sealing ring 40 and slips 4| are employed as supplemental sealing and gripping means, respectively.

' Due to their very simple construction, the plugs herein" desbribed may be easily' a1'1'd-readily drilled out whenever it isdesir'ed to remov'e'the'm fromthepipe. T?

It will be understood'that' various changes and alterations may be made in the'details' of this inyention and in the various embodiments there-; of herein described without -departing'from the scope of the appended claims but, within the spirit of this invention.

What I claim and desire to secure byLetters Patehtis: a

l. A well plugging device of the character described, comprising, a ductile metallic body insertible in a well pipe, a downwardly and inwardly tapering bore in said body, a wedge member similar in shape to said bore longitudinally movable interiorly of said bore to expand the wall of said body, a piston rod slidable axially through said wedge member, means for anchoring the inner end of said piston rod to said body below the inner end of said wedge member, a cylinder enclosing the outer end of said rod, a piston mounted on the outer end of said rod within said cylinder, and explosive material disposed in said cylinder below said piston.

2. A well plugging device of the character described, comprising, a hollow ductile metallic body insertible in a well pipe, a downwardly and inwardly tapering bore in said body, a wedge member similar in shape to said bore longitudinally movable interiorly of said bore to radially expand the wall thereof, an outwardly opening valved passageway through the wall of said body communicating with the bore thereof below the inner end of said wedge member at its most advanced inward position in said bore, and means for actuating said wedge member.

3. A well plugging device of the character described, comprising, a, generally cylindrical ductile metallic body insertible in a well pipe, a downwardly tapering generally conical bore in said body closed at its lower end, a wedge member similar in shape to said bore movable longitudinally therein to radially expand the wall thereof, circumferential sealing means mounted on the exterior of said wedge member for slidable sealing engagement with the wall of said bore, a passageway through the wall of said body communicating with said bore below the inner end of said wedge member at its most advanced inward position in said bore, an outwardly opening check valve in said passageway, and explosive means for actuating said wedge member.

4. A well plugging device of the character described, comprising, a generally cylindrical ductile metallic body insertible in a well pipe, a downwardly and inwardly tapering generally conical bore in said body closed at its lower end, a, wedge member similar in shape to said bore longitudinally movable therein to radially expand the wall of said bore, annular seal means arranged between the exterior of said wedge member and the bore wall, an outwardly opening valved passageway through the wall of said body communicating with said bore below the inner end of said wedge member at its most advanced inward position in said bore, a piston rod slidably axially through said wedge member, frangible means anchoring the inner end of said piston rod in said bore below the inner end of said wedge member, a cylinder enclosing the outer end of said rod, a piston mounted on the outer end of said rod reciprocable in said cylinder, an explosive charge disposed in said cylinder below said piston, and means for firing said charge.

"- 1.5, A well plusxing device according to clain} 4,

wherein said firing means comprises a passageway extending through the outer end portion of said rod to provide communication between the portions of said cylinder above and-below said piston, and means for firing an initiating explosive charge in the portion of said cylinder above'said piston.

6. A well plugging devioeaccording to claim 4 wherein said piston rod has an enlargement on its lower end engageable with the lower end of said wedge member. I LESTER: W. TOELKE.

8 Beferences (liked in the file of this patent UNITED STATES PATENTS Number Name Date 1 Alexander June 1-5, 1226 Henderson Jan. 31,1928 Broyles Feb. 13, 1940 Roe Aug. 27, 1940 English Sept. 1-0; 1940 I Baker Apr. 3, I945

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