US2690123A - Jet gun perforator for wells - Google Patents

Description

Sept. 28, 154 DY 2,690,123

' JET GUN PERFORATOR FOR WELLS Filed Sept. 11, 1950 21 Fl. I. FIG- 2- INVENTOR.

William E. Kanady,

ATTORNEY.

Patented Sept. 28, 1954 2 696,123 UN I TED .ATENT FF] CE 2,690,123 'JET GUNPERFORATOR FDR WELLS William Kanady, Houston, Tex., assignor,. by

meme-assignments, to Standard Oil Development Company, Elizabeth, N. J., a, corporation of Delaware Application's'eptember 11, 1950, SerialNo..'184,167 2 Claims. (01. 102-203) .1 p 5 I is them from is invention relates to guns for perf r i charges of ehploslves and Sea g in oil wells or the 111 and more particufluid 1n the well bore. The charges are merely 1aflyto guns which use shaped, chargesmf xplaced in the container so that expensive ll'ldiplosive to perforate casing with jet action. vidual seals are not required, and each charge is r in 011 n ith 5 enclosed in a sealed pressure resistant envelope. chi 32 2; lig li ghioh uti lize the Monroe e spaces in the container between the charges efiect are now common. Guns constructed-for 01- explos1ve are filled Wlbh inert filling rnaterial. this purpose ordinarily consist of a steel body'or in accordance with the p esent invention it is carriage which is providedwith-anumber oiports p p ed to use a gunhavlnga container of hi h they eharges'of explosive are individ- 10 xible material for maintaining a seal around uallymounted and sealed. :Since the carriageis c arges of explosive. After the gun has ordinarily hollow and the interior kept free from hee11 10Wered d0Wn through tubing 11a Well, the liquid contamination as the gun is lowered ic container is expanded or bl wn up y through mud or the like-in the wellbore, it must hydrostatic pressure so as to bring the shaped be built strong enough, and each: seal must be 15 Charges out into the P p position Ior firing. to

l ehi hfiuid perforate casin beneath the tubing. i iii fn fi eg if 5235 $2112 Thi cost 0f such The jects of the invention will be apparent carriages and the expense involved in reloading h fOHOWlIIg d scr ption, talien 1n connecthem is high tron with the accompanying drawings in which:

Expendible carriages, such-as those made of 1 1S a gmenta-ry vertical cross-sect onal cardboard, various plastics or the like arepro- Vlew of tubmg (and s ng 1n an 011 Well with a posed in the patent to Davis and'BurrowsNo un perfc h cqnstmcted h acco gh with 2,399,211, but these have not come into general h h lhvehtloh lhwelefi 111th 1 93 111011 thereuse perhapsbecause of the inability of such mathe W Of the gun being in side elevation terials to Withstand high bottom hole pressures. ihg g gg the Shape fo e the container is arria es of solid concrete have alsobeen proposed an d these have been commercially used, 2 1S a View smfllar to hat of Fig. l but bowing a portion of the container cut awa and 1 ome e0 le-skilled in the y i tZ h h i ii es r le becaiie f their tendency luufqhmtmg the Shape 01 e C ntainer and the to burst h Casing position of the charges of explosive after the con- The problem of reducin the expense of jet agg f i V perforation has recently been complicated by ann 1 t 1 'h -s vlonal View of other factor. It has been proposed to lower perf of the $111} h sand fcrating guns through tubing inside the casing vReerrmg to drawlhg all, It Will be in an. oil Well. See for example the application of seenythat the caslhghf an Well 15 there 11- Theodore A. Huber Serial No. 133,025, filed Demshated l Tublng l3 s shown within the ceinber 15 1949, a; Methodof Completing and f l W1th Its lower e d just above the por- Renairing Oil Wells Where the use ofa casingnon f the s Whlch Is o b perforated. An perforating gun capable of being rnnthrough elongated 00111751111? Whlch Constitutes the tubing is required. Large savings in time and 40 body of the gun, is Shown as having been lowcost in drillincan be effe ted in this way if efered n through t t i is of an electric f tiperforzvfion can a accomplished cable 5, although it is within the purview of the In accordance with ap lication Serial No. mvehtloh to Pump the gun down the tubing 0 184,161, filed September 11, 1950, now Patent No. let fall by gravity and a no ct icalv conacaawo, dated May 26, 1953,.by Theodore A. 1160610115 F9 lJhe parts therem- Huber, it is proposed to solve the problem of proposltlon the gun P Operly With p ct to viding elfective firing power to perforate casing the Puhlhg so that it Will upy the proper withan assembly which. is run into and. out of Vertmal 13051151011 in the Casing d or other the well through tubin by arranging. the guns purposes as l D h Y be d c bed, the botjn their carriage o gun body on trunnjons and tom of the 1311191118 [3 15 provided With a 10031101 by providing means for rotating them from the Seatlng nd th top of the container vertical positions which they occupy While being 14 is provided with a d in a tapered lowered into the well, into horizontal'firing posi- Shoulder adapted to come to e t on the ring tions. Inasmuch as the guns may be fired by d Bfieot a Seal therewith. electricity, Huber proposed to-employ an. electric The head i5 hollow and it is p ov d With motor to rotate them exactly the right amount. ainumber of ports 20 b v the shoulder It so as In accordance with the application of Earl to establish connections between the interior of Babcock, Serial No. 184,166, filed on event date the container I l and the fluid in the tubing l3 herewith, it is proposed to "make a camage for Whether or not the head I! is seated on the ring jet perforator gunsof a thin-expendible outer I6. tubular container which completely surrounds Within the container 14 there are a-number of shaped charges of explosive 2|, each individually sealed in its own pressure resistant envelope. These charges may be arranged all pointing the same way or all pointing in different directions. As shown they alternately point to the left and right. They are individually secured to the wall of the container I4 so that when the container expands, as shown in Fig. 2, the charges are so positioned with respect to the casing I2 as to have the proper stand-off distance for most effective perforation of the casing.

If an electric cable I5 is employed to lower the gun into the well, the charges 2I may be fired electrically and, for purposes of illustration, a cable 22 is shown inside the container I l with leads 23 coming off to each charge 2I. If the charges are in copper or other metallic housings, these housings may be grounded by one of the wires in the cable 22 and leads 2?. to the head I'I while another wire of the cable 22 and leads 23 is connected to the conductor of the lowering cable I5. If no electrical cable I5 is employed, the charges may be fired by a prima cord connected to a firing system located in the head H in accordance with the teachings of the Babcock application referred to above.

As shown in Figs. 2 and 3, the container It may be made of rubber, neoprene, elastic plastic or like expendible material. It could be made of canvas or other cloth and it need not be absolutely water tight though it must be so nearly so as to cause it to expand when the internal pressure exceeds the external pressure thereof. It may be provided with vertically extending cords 24, as shown in Fig. 3 of cotton, nylon, steel or other material. These cords serve to hold the container in shape, to some extent, but their main purpose is to make a connection from the lower shoe 25 of the gun body to the head 11. Since it is intended that the body I4 blow up when the charges are fired, and since it is desirable to remove from the well as much of the remnants thereof as possible, without fishing for them, it is desirable to maintain connection with as much of the container III as possible. However, the invention is not limited to such a construction and in any event the cords 24 should not be so strong but what they will break and permit the head IT to be retrieved from the well, no matter what happens to the remainder of the gun when it is fired.

In considering the operation of the gun, let it be assumed that the well bore is filled with oil and it is desired to lower the gun down through the tubing I3 and perforate the casing I2. The gun is placed in the tubing I3 at the well head while it is empty so that there will be no tendency for the container I4 to bulge or belly out which would cause difficulty in placing it in the tubing. After it is in the tubing it may fill with oil from the tubing but this is of no moment since the ports 29 in the head are open and there is no difference in pressure across the walls of the container I4 and hence no forces tending to move it out of the natural hanging position shown in Fig. 1.

When the gun is in position at the bottom of the tubing as shown in Fig. 1, pressure is put on the oil in the tubing I3, as by a pump at the surface of the ground. Since the ports are above the seating ring Hi, this will create a difference in pressure between the inside and outside of the tubing and a difierential pressure across the walls of container I4 and cause the gun to take the shape shown in Fig. 2, with the charges 2I in the optimum position for effective perforation of the casing I2 when they are fired. If fired electrically, a source of electricity may then be connected to the conductor of the cable I5 and all the charges 2| fired simultaneously or practically so. The head I1, so much of the container I4 as remains attached thereto and the shoe 25, if it is still attached to the head I! may then be retrieved from the well by the cable I5 and the well completed in accordance with the teachings of the Huber application, Serial No. 133,025 mentioned above.

While only one embodiment of the invention has been shown and described herein it is obvious that various changes may be made without departing from the spirit of the invention or the scope of the annexed claims.

I claim:

1. In an arrangement for perforating casing in an oil well or the like, in combination, an elongated, hollow, expansible, flexible container small enough to be run through tubing inside the casing to be perforated, said tubing having a ring affixed to its inner surface adjacent its lower end, a head on said container having means for engaging the ring in the lower end of the tubing and maintaining a seal therewith, said head having ports for maintaining fluid connection from a point above said engaging means to the interior of said container and a plurality of shaped charges of explosive within the container and individually secured to the wall thereof, the arrangement being such that said head may support the container and charges on the ring at the lower end of the tubing and the charges may then be brought into optimum firing position with respect to the casing by exerting fiuid pressure in the tubing.

2. In an arrangement for perforating casing in an oil well or the like, in combination, a tubing string suspended in said oil well within said casing, a ring affixed to the inner surface of said tubing adjacent its lower end, an elongated, hollow, expansible, flexible container small enough to be run through said tubing, a head on said container small enough in diameter to pass through said tubing and having means for engaging said ring and maintaining a seal therewith, said head having ports for maintaining fluid connection from a point above said engaging means to the interior of said container and a plurality of shaped charges of explosive within the container and individually secured to the wall thereof, the arrangement being such that said head may support the container and charges on said ring and the charges may then be brought into optimum firing position with respect to the casing by exerting fiuid pressure in the tubing above said ring.

References Cited in the file of this patent UNITED STATES PATENTS

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