Expansible plug for oil wells

Application filed April 18, 1923. Serial No. 832,911.

To dll whom it may concern:

Be it known that I, Harry M. Anderson, a citizen of the United States, residing at San Antonio, in the county of Bexar and 5 State of Texas, have invented certain new and useful Improvements in Expansible Plugs for Oil Wells, of which the following is a specification.

This invention relates to improvements in ¹⁰ expansible plugs for oil wells.

One of the objects of the present invention is to provide a plug which may be readily and economically manufactured from cheap material and without the employment ¹⁵ of any specially designed machinery and which, in use, may be readily disposed within the well and expanded to plug the well to prevent the inflow of water into the bottom thereof.

²⁰ Another object of the invention is’ to provide a plug for oil wells which will bo adapted to expand to true cylindrical form so that upon expansion within the well tubing, it will securely seal the tubing so that ²⁵ there can be no leakage of water or * oil past the plug.

Another object of the invention is to provide a plug so constructed that when ocfiasion requires, a quantity of putty or other ³⁰ sealing material may be disposed within the plug when the plug is introduced into the well, and will be adapted to be forced to the exterior of the plug when the expanding mandrel is driven into place.

³⁸ In the accompanying drawings:

Figure 1 is a view in elevation of the plug embodying the invention, the elements of the expansible body being shown relatively longitudinally displaced so as to re⁴⁰ duce the diameter of the body of the plug;

Figure 2 is a view similar to Figure 1 illustrating the plug expanded;

Figure 3 is a horizontal sectional view on the line 3—3 of Figure 1 looking in the di⁴⁵ rection indicated by the arrows;

Figure 4 is a similar view on the line 4—4 of Figure 2 looking in the direction indicated by the arrows; .. '

Figure 5 is a group perspective view illus⁵⁰ trating the component parts of the plug disassembled but arranged substantially in the relationship which they will occupy when assembled, so far as relative position is concerned.

⁶⁸ Briefly stated, the plug embodying the invention comprises an expansible body indi cated in general by the numeral 1, and an expanding mandrel which is indicated in general by the numeral 2. The body 1, in its expanded form, takes the shape of a cylin- ⁶⁰derand the body is made up of a plurality of elements or staves certain of which are indicated by the numeral 3 and others by the numeral 4. All of the elements 3 are of counter-part form of substantially rectangu- ⁸⁵lar cross section, and likewise all of the elements 4 ai’e of counter-part form of substantially triangular cross section. Each element or stave 3 has downwardly converging flat, side faces 7 and upwardly converging ⁷⁰inner and outer faces, tbe inner face 6 being flat but the outer surface is transversely rounded as indicated by the numeral 5 so as to form a portion of the cylindrical surface of the assembled body 1. Furthermore, this ⁷⁵face 5 of each element 3 is disposed perpendicular and is parallel with the axis of the plug as a whole.

Each element 4 of the expansible body of the plug is of triangular cross section and ⁸⁰has its face 8 which is presented outwardly, in the body 1 or assembled relation of the elements, transversely rounded as indicated by the numeral 8 on the curve of the cylinder body 1. As in the case of the face 5 of each ⁸⁵element 3, the face 8 of the glement 4 is disposed perpendicular, in the · assemblage of ’ the elements forming the body 1, and the line of longitudinal extent of this face is parallel to the axis of the plug as a whole. The two 90 remaining faces of each element 4, which faces are indicated by the numeral 9, are flat and are located in planes converging inwardly from the face 8 and meeting to form a common inner edge, and these faces are 95 likewise converging in the direction of the upper end of the element. By reference to the drawings and particularly by comparison of Figures 1 and 3 and 2 and 4, it will be understood that when the elements 3 and 4 100 are assembled by alternately arranging the elements about an axis and with the lower and minor ends of the elements 3 entering between the lower and major ends of the elements 4, and the upper ends of the two 105 sets of elements arranged in a similar manner, there will be produced a substantially cylindrical body 1 having a bore extending therethrough, the walls of which are defined by the faces 6 of the four elements 3, the no meeting rear or inner edges of the side faces 9 of the elements 4 meeting in the angles be?

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1,507,983 tween adjacent faces 6 of the elements 3. This bore, due to the oblique disposal of the faces 6 of the elements 3, is tapered from its upper to its lower end, or in other words, 5 from the upper end of the plug body to the lower end of said body.

It will also be understood, and particularly by reference to Figure 1 of the drawings, that when the elements 3 and 4 are respec10 tively moved longitudinally upwardly and downwardly with relation to each other, the body will be contracted or reduced in circumference thus adapting it for ready introduction into the well tube to be plugged. 15 The elements or staves 3 and 4, when assembled? to form the cylindrical body 1, together form a tapered point 15 at the lower end of the body 1 in order to still further facilitate the insertion of . the plug in the well.

The expanding mandrel 2 of the plug is in the form of an elongated-pyramidal core 10, the major upper end of which is provided with a preferably cylindrical driving head 11. The core 10 is four-sided and 25 is tapered to a point at its lower end.

In using the plug and in setting the same into place in the well tubing, the elements 3 and 4 are assembled and are then longitudinally relatively displaced as previously 30 pointed out and as illustrated in Figure 1 of the drawings so that the plug body will then be of a reduced diameter. The assemblage is then introduced into the well tube, the mandrel 2 having been loosely 35 fitted into the bore of the body 1 provided by the assemblage of elements, and pressure or blows are then imposed upon the upper end of the expanding mandrel to force the same into the bore. Due to the tapered 40 form of the bore and the tapered form of the mandrel, the elements comprising the body of the plug will be expanded, and as the elements expand the body will assume a true cylindrical form and will finally com45 pletely fill and snugly fit within the well tube. The lower ends of the elements 4 of the body will of course rest upon the bottom of the well at the time the elements are relatively displaced as shown in Figure 50 1 and it will be understood that as pressure is imposed or blows are delivered upon the expanding mandrel, the elements 3 and 4 will be longitudinally moved together, their obliquely disposed side . faces riding over 55 one another and maintaining a close and fluid-tight contact. The elements comprising the body 1 of the plug, as well as the mandrel 2, will preferably be made of relatively soft wood and it will therefore be eo evident that when the plug has been expanded within the well tube, the inherent properties of the wood comprising the elements and the mandrel will insure of a fluidtight fit. It will also he evident that the 55 elements 3 only are acted upon by the man drel and that the elements 4 perform a useful and indispensable function by wedging between the side faces of adjacent ones of the elements 3 as the said elements 3 are forced outwardly and relatively away from 70 each other by the driving in of the expanding mandrel, so that gaps which would otherwise occur between the said faces of the elements 3, will be completely closed, thus insuring of a fluid-tight fit of the plug 75 body, 1 within the well tube.

Under some conditions, as for example, where the formation into which the plug is to be set is of a porous nature, it will be desirable to make use of a sealing sub- 80 stance such for example as putty and this may be accomplished, during the use of the plug embodying the invention, by filling in a suitable quantity of putty, in a plastic state, in the bore of the body as provided 85 by the assemblage of body elements, the introduction of the expanding mandrel and the driving of this mandrel into place within the bore, serving to expel the putty and cause the same to exude through the cracks ⁹⁰between the body elements of the plug and thus seal the pores of the rock formation.

From the foregoing description of the invention it will be seen that there is provided a plug which may be produced at an ⁸⁵exceptionally low cost and from inexpensive material, and that the component elements of the plug may be readily assembled and the expanding mandrel readily introduced into the bore in the body of the plug and ¹⁰⁰driven or otherwise forced into place so as to expand the elements and thus cause the plug to completely fill and close the well tube. Because of the peculiar contour of the different body elements of the plug, the 105 body of the plug, when expanded, will assume and maintain a true cylindrical form thus insuring of an exact fit within the well tube.' It will furthermore be evident that any pressure from above or from below, no exerted upon the plug after it has been set into place, will serve to only the more tightly wedge the plug in place within the well tube and will not effect a release of the plug as is likely in other constructions heretofore 115 employed.