US2516041A - Shothole water seal - Google Patents

Description

A. J. ABRAMs SHOTHOLE WATER SEAL 2 Sheets-Sheet l l N VEN TUR QM//v J Afan/m15 A T TORNEI July 18, 1950 Filed March 26, 1946 Inf July 18, 1950 Filed March 26, 1946 A. J. ABRAMS SHOTHOLE WATER SEAL 2 Sheets-Sheet 2 /N VEN TOR A T TORNEI Patented July 18, 1950 SHUTHOLE WATER SEAL ArmandLhnms,

Ten. assisnor, by

Dallas, menne assignment, to Soeony-Vacuum il Incorporated corporation of New York New York, N. Y., a

manden mmh ze, 194s. sensi No. 651,291

4 claims. (el. 1oz-so) uable information with respect to the character l oftbesuhsurfacestrata. u

Inconductingseismicsurveysinordertodetermine the probability of oil deposits in various vsectionsoithecountrynithasoitenheenlfound that the subsurface strata into which the shotholes penetrate are of such o porous character that it is diilcult to hold water in them. It freqnently happens that the porous character of such subsurface strata occurs where water is difiiculttoobtainandwhicbisexpensivetohaul from" the nearest available source. The use of water in each shothole is relatively important since itnprovides the needed tamp for the explosive charge. If a temp were not provided, a substantial proportion of the energy generated by the detonation of the charge would be dissipated up the hole and only a small proportion of' it directed into the earth.

In carrying out the present invention in one form thereof, there is provided a means for di recig and concentrating in any predetermined mnethe energy resulting from detonatimi of the explosive charge in the shothole. This means comprises a liquid container disposed lengthwise of the shothole for holding a. predetermined quantity of liquid to form a tamp of the desired weight above the explosive charge. For easy insertion of the container into the shothole, it is preferably folded so that its cross-sectional area is considerably smaller than. that of the shothole.

t It is held in its folded posiia'on by means of moisy ture-absorbing paper or other material distributed long the length and overlapping the folded porons of the container which loses its strength when wet. t... fn :lv after insertion oi the folded container into the shothole, the addition of water meistens the paper-holding means. which thereupon breaks to permit the unfolding of the container into intimate contact with the walls of the shothole.

For a more detailed understanding of the invention. and for further objects and advantages thereof, reference is to be had to the following v taken'inconjunctionwiththeaccomdrawings, in which:

Fig. 1 is an elevation of one embodiment of the invention shown in a shothole:

Fig.2isa f f viewtakenontheline 2-2 ofFig- 1;

Fig. 3 is a sectional view with the lower part of the container partly-expanded or unfolded:

Fig. 4 illustrates the lower portion of the container fully expanded or unfolded;

Fig. 5 is an elevation similar to Fig. 1 of another modication of the invention;

Fig. 6 is a sectional view taken on the line 6-6 of Fig. 5; and

Fig. 7 illustrates a further modication of the invention which may be utilized with either of the modifications of Fig. l or 5.

Referring to the drawings. the invention has been shown'as applied to a shothole I0 which extends from the surface Il of the earth to a suitable depth therebelow; for example, 60 to 100 feet`or more, or less. Where the walls of the shothole I0 are porous or where the material forming the walls is of acharacter which rapidly absorbs water, it will be understood that it will he very difficult to produce and maintain a level of water within the shothole I0 high enough to provide adequate tamping for an explosive charge disposed at the bottom of the hole. In accordance with the present invention, not only is there provided the minimum amount of water needed for a tamp, but the weight of the temp is controlled uniformly for successive shots.

After drilling of the shothole IU, there is inserted therein a container illustrated as having anupper section I2 and a lower section I3. To provide weight `at the bottom of the container and to assist in guiding it into the shothole I0, spacing spokes I4 attached to a. head plate I5 are provided. Thespokes I4 may be omitted, if desired, and the head plate I5 made of considerable Weight to insure the lowering of the container in the shothole. The upper section I2 of the container is preferably somewhat smaller in diameter than the Ashothole I0, and, as shown, the lower section I3 is folded, Fig. 2, so that its cross-sectional area is also smaller than that of the shothole I0. The lower section I3 is restrained in its folded position by means of paper bands I1, I8, and I 9. The container as a, whole may be made of canvas, preferably waterproofed to minimize leakage of water. In general, the explosive charge will be placed in the bottom of the container I3 before it is lowered into the shothole. However. after the container is in the position illustrated in Fig. 1, a charge of dynamite or other explosive may be lowered to the bottom of the container. Water is then added to ll the container to the desired level and to provide a tamp of adequate weight to insure the localization and concentration of the released energy adjacent the bottom of the shothole and to minimize its loss in the upward direction.

The addition of the water to the container,

either by slow seepage or external flow over the surface, produces a wetting or moistening of the paper bands II-I9 and so reduces their strength that the weight of the water inthe lower section I3 causes them to break. As shown in Fig. 2, the lower section may be provided with a series of folds 2t. Moreover, instead of the lower section I3 being constructed entirely of canvas, it may be made out of fibre sections 2l to which the folds 2t of canvas or other material may be suitably secured as by sewing and/or cementing. While it has been suggested that the bands require moistening, it is to be understood that need not be the case since the only requirement is that the weight of the water in the section I3 shall produce a force on the bands il-I 9 great enough to break them. Since the lower end of the drill hole is nearly always wet due to the use of water in drilling it and also due to subsurface water, in some cases, the paper bands will soon absorb water for reduction in their strength. When this occurs, the weight of the water moves the sections 2i outwardly, as shown in Fig. 3, unfolding the folds 26 until the sections 2i are in contact with the inner wall of the shothole It. The shothole is then effectively plugged or blocked. The fully expanded position of the lower section I3 is shown in Fig. 4.

Since the container is provided with a closure at its lower end, the tamp may be made effective with the explosive charge supported at points above the bottom of the container i3. When the container is supported by a ring 22, or otherwise, with its lower end above the bottom of the shothole iii, the tamp of water disposed therein will be eiective to localize the energy 4of the explosive charge at the desired point.

In some locations, the subsurface strata may not only be porous but there may also be encountered relatively large voids, as indicated at 25. Fig. 5. These' voids may be relatively small or they may be large. They may connect to fissures and otherwise render it diilicult to hold water within the shothole lil. Instead of the container shown in Figs. 1-4, a water-tamp may be provided by a container 2e formed of canvas or of a heavy waterproofed kraft paper provided with a plurality of folds 2i of the pleated or accordion type. The container 25 is held in its folded position by means of a spirally-Wound paper strip 30 extending from substantially the top to the bottom of the shothole it. In this case, the explosive charge 32 is disposed at the bottom of the shothole ill, leadwires -33 and 34 extending therefrom to the firing or detonating apparatus 35. As in the case of Figs. 1-4, the strip 3U may be of paper which loses its strength after absorption of moisture or wetting thereof, or it may be of a material insufficiently strong to withstand the expanding force due to the weight of water within the container 2S. In either case,

the weight of the water breaks the tape and permits the container 26 to expand outwardly and into engagement with the wall of the shothole I0.

Where the head plate or the weight at the bottom of the container is not adequate to insure easy insertion of the container in the shothole, there may be provided one or more tabs, such-as a tab 3l shown in Fig. 7, having a reinforced opening or eyelet 39 into which there may be inserted a long rod for forcibly moving the container 3l downwardly in the shothole. It is to be understood,v of course, that the tab 31, together with its reinforced eyelet ,39, may be applied to' the modifications of Figs. 1 and 5, or in some cases it may be utilized alone and without the need for the folding of the container prior to insertion in the shothole. The eyelet 39 may be formed in the body-portion of the container I3 by closing the lower end, as by sewing or cementing it at a point above the eyelet.

It is to be understood that other modifications may be made within the spirit and scope of the 1 appended claims.

for directing and concentrating in a prede-v termined zone the energy resulting from detonation of an explosive charge in a shothole comprising a liquid retaining, moisture permeable container folded to a relatively small size for insertion lengthwise of said shothole and moisture absorbing paper means distributed along the length and overlapping the folded portions of said container for absorbing moisture from said moisture permeable container and for holding said container folded until after absorption of moisture by said paper means which. upon addition of Water to said container, automatically wets said paper means to` decrease its strength for breakage by the weight of said water to permit unfolding of said container.

2. In a seismic wave generating system, means for directing and concentrating in a predetermined zone the energy resulting from detonation of an explosive charge in a shothole comprising an abrasive resistant, liquid retaining fabric container folded t0 a relatively small size for insertion lengthwise of said shothole, and moisture absorbing paper means distributed along the length and overlapping the folded portions of said fabric container to absorb moisture therefrom and to hold said fabric container folded, which paper means, upon the addition of water to said container, automatically is 'weakened for breakage by the weight of said water to permit unfolding of said container.

3. In a seismic wave generating system, means for directing and concentrating in a predetermined zone the energy resulting from detona ing said container folded until after' absorption of moisture of said paper means which paper means, upon the addition of'water'to said container, automatically' decreases its strength for breakage by the weight of said water to permit unfolding of said container.

4. In a seismic wave generating system, means for. directing and concentrating in a predetermined zone the energy resulting from detonation of an explosive charge in a shothole comprising an abrasive resisting, liquid retaining container folded to a relatively small size for insertion lengthwise oi said shothole, and moisture absorbing paper means encircling said folded container a plurality of times, the respective encirclements being at regions spaced along the length of said container with intervening spaces therebetween for holding said container folded until after absorption of moisture by said paper means which upon overiiow of water added to said container and the wetting of the exterior thereof automatically wets said encircling paper means to decrease its strength for breakage by the weight of said water in said container to permit unfolding of said container.

' ARMAND J. ABRAMS.

REFERENCES CITED The followingY references are of record in theYV le of this patent:

UNITED STATES PATENTS Number Number Name Date Hallock Sept. 28, 1880 Settle June 8, 1886 Babney Jan. 25. 1910 Ellis Mar. 27, 1917 Clark Aug. 14, 1923 Holderer June 30, 1925 Lindner Sept. 13, 1927 Kennedy Apr. 13, 1943 Lubelsky et al July 2, 1946 FOREIGN PATENTS Country Date Great Britain of 1886 Great Britain of 1910 Great Britain ..--1 Nov.,22, 1923 Germany of 1912

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