US120186A - Improvement in processes of removing obstructions in oil-wells - Google Patents

Description

JAMES DICKEY.

Improvement in Torpedoes for Oil Wells. N0. 120,186. Patented 0ct.24,1871.

UNITED STATES 120m-sc PATENT OFFICE.

`JAMES .DIcKn or oIL crrY, IENNsYLvANIA.

IMPROVEMENT IN PROCESSES OF REMOVING OBSTRUCTIONS IN OIL-WELLS.

Specification forming part of Letters Patent No. 120,186, dated October 24, 1871.

thereof, reference being` had to the accompanying drawing making part of this specification, in which- Figure 1 is a vertical section of an oil-well to exhibit the relations ofl the several stratums of' rock through which it was bored, and the general direction of' the oil-bearing fissures or cavities in the rock within the well. Fig. 2 is a horizontal section of' the oil-bearing fissures or cavities. Fig. 3 is an elevation of my improved apparatus on a larger scale than the one representedin the well; and Fig. 4, a vertical section of the said apparatus representing the internal structure thereof. p

The saine letters indicate like parts in the several figures.

Fig. l ofthe accompanying drawing represents the general order in which the several stratums are arranged in the oil-region of Pennsylvania; and as the first and second stratums a and b, of soap-stone, are generally of' great thickness, they are reduced in the drawing by broken lines. The first sand or oil-bearing rock is represented at c, and is unimportant, salt water being usually found in the same fissures; and for that and other reasons, that part of the well extending to the lower part of the rst soap-stone stratum a, is cased by a tube and seed-bag, d. The second oil-bearing stratum, e, is a coarse sand-stone varying from six to twenty feet in thickness, overlaid with stratified shells and shale rock. And the third or principal oil-bearing stratum, f, is a conglomerate of white and yellow pebbles and sand, underlying several layers or stratums, g, of shale, the stratum gradually increasing in thickness as they approach the sand or oil-bearing rock. Soft slate is found between the stratum of shale, and generally gas, which is inflammable, and which is usually collected and used as fuel. The sand-rock stratum is from ten to fifty feet in thickness. Between the lower stratum of shale and the stratum of sand-rock are numer` ous fissures or cavities represented in Figs. 1

`deposited in the fissures and against the walls of the well, and so deposited becomes of' a waxhke consistency, which, in theucourse of' time, clogs and stops the fissures so that the oil cannot be forced through into the well bythe heavy pressure to which it is exposed. ln some instances the fissures can be opened and the parafiine removed by the firing of' torpedoes; but,

in many instances, that method instead of yin-` creasing the productiveness of the well, actually stops up the fissures so that the well will no longer supply oil. If the oil-bearing fissures are largest at the bore of the well, as at IL, and grad- ,ually smaller although leading to other fissures,

the force ofthe explosion will drive the parafiine into and completely cork or stop up the smaller part of the fissures. The object of my invention is to so loosen and reduce the paraffne by forcing flame into the fissures, that the internal pressure to which the oil is exposed will force it out of the issures into the bore of the well, from which it can be readily drawn out. To accomplish this, I make use of an apparatus which I denominate a rocket, and which is represented in the accompanying drawing, in which i' is a cylindrical case, made of sheet metal, or paper, or other suitable material, with a bottom, j, and top, k, which case is to be filled with slowburning powder. The upper endof this casez' is fitted to another case, l, of the same diameter, which is simply to increase the weight and length of the entire appara-tus, so that, when dropped into the well, as will be hereinafter described, it will be properly guided. The required weight of the entire apparatus can be obtained by making this part of the case of thick metal, or by filling it with any liquid or granular matter. The upper end of' the case Z I prefer to make conical. Within the compound ca se i l there is a central tube, m, extending the whole length, with a suitable removable cap or stopper, n, at the upper end. The bottomj of the case z' I prefer to make of cast metal.- The upper part has a cylindrical flanch to fit over the case so that it can be slipped on and ofi', and it fulminate priming.

is also formed with a hollow central plug, o, which lits into the lower end of the cyliividrical tube m, and the bore oi' this plug is of a sufficient capacity to receive a small cartridge with When the cartridge is tired the llame passes through a touch-hole in the upper end ot' the plug to the charge of powder in the case For the purpose of tiring the cartridge, a small cylindrical hammer, p, is fitted to slide in the cartridge-claimber of the plug o, and this hammer is a central projection from a circlila-r disk, q, the periphery of which is fitted to slide freely within a cylindrical ilanch, fr, projectin g from the bottom j ofthe case The central tube 'm is to be filled with chlorate of potash or equivalent substance, which will evolve oxygen gas when heated, and thc cascfi is to be iilled wi th slow-burnin g powderthat is,coarsegrained powder-which is introduced through the lower end when the bottom j is removed; some of the said charge of powder being placed in the lower end of the central tube on., to be ignited by the lire from the cartridge when that is fired; and the fire from the powder at the lower end of the central tube communicates with the charge in the'case 'L' through lateral holes in the central tube, as represented at s s.

The apparatus, charged as above', is applied to oil-wells in the following' manner: rlhe liquid is pumped out ot the well to some distance below the oil-bearing rock, say to the line t, andthe apparatus is dropped into the well down which it descends with accelerated velocity, and when it reaches the liquid in the well, the disk q striking the liquid forces the hammer p against the cartridge, which is thereby iired, and the fire communicated to the charge of powder, the firing of which drives out the bottom j of the case, and, by reaction, the case is forced up toward the top of the well in the same manner as a rocket is projected in the air. rIhe heat generated by the firing of the powder acts on the charge of chlorate of potash and evolves oxygen, which .unites with the inflammable gases always present in oil-wells, and the heated :llame thusproduced is forced into all the fissures and cavities of the rock and melts the paraiiine, while, at the same time. the force due to the expansion of the gases Vacts upward on the rock, having an up-heaving tendency. Shortly after the explosion the gases are condensed and a reaction takes place. The oil in the fissures leading to the well, and which in the natural condition are under heavy pressure, due, as is generally believed, to the force of gases in the rock or natural reservoirs of oil, and which, by the force of the explosion and inflaming of the. gases in the well was forced back 'away from the well, on being relieved by the condensation from the pressure induced, which drove it back, reacts, and is in turn forced toward the well, and thereby drives the melted or partially melted parafine and other deposits out of the fissures into the well, thereby eifectually reopening the passages which had been obstructed. rlhis process may also be worked by pumping out the liquid inthe well to about the level of the oil-bearin g rock, or a little above or below it, and charging the case z' wi th faster-burning powder, and with or without the charge of chlorate of potash. When such a rocket is dropped into the well, the explosion ot' the charge takes place at the instant of striking the surface of the liquid in the well, and the downward force, due to the momentum ofthe weight of the rocket descending with accelerated velocity, will resist the upward force of the explosion, which will then be mainly exerted downward on the liquid in the well, and laterally against the walls ofthe well. In this way the rock will be eifectually fractmed, and the oil in the lissures driven back, as before described, and then when relieved from the force of the explosion, will react by the force which naturally tends to force it toward the well, and more eifectually clear out the paraiiine and other obstructions than by the mode of using torpedoes, heretofore employed, in which Water-tamping is employed, because, with Water-tamping, the whole column of liquid in the well-is lifted at the same time that the oil in the fissures is forced away from the Well by the force of the explosion; and after the explosion, when the oil in the fissures reacts, it is eifectually resisted by. the action of the tamping column of water as it is falling back to its original level, no such counteracting force being present with my improved process. I prefer to make my improved apparatus of a diameter from one to three inches less than the bore of the well.

What I claim as my invention, and desire to secure by Letters Patent, is-v 1. The improved process of clearing obstructions in oil-Wells by dropping onto the liquid in the well a rocket, which will tire the contained charge on striking the surface of the liquid in the Well, thereby using' the momentum of the falling apparatus to resist the upward force of the discharge, substantially as and for the purpose set forth.

2. In the apparatus above described, the case for containing the powder, in combination with t .1e movable bottom and the sliding hammer for ii ing the charge when it strikes the liquid in the well, substantially as and for the purpose specified.

3. The combination of the case for containing the charge of powder with the chamber for containing chlorate of potash or equivalent chemical agent, and the means for firing the charge, substantially as and for the purpose specified.

JAMES DICKEY.

Witnesses WM. H. Brsrror, A. J. DELACY. (124)

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