US 2993554 A
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y 1951' B. H. TOWELL ETAL 2,993,554
WELL SOUNDING GUN 2 Sheets-Sheet 1 Filed May 31, 1956 Air July 25, 1961 Filed May 31, 1956 B. H. TOWELL EIAL WELL SOUNDING GUN 2 Sheets-Sheet 2 United Stat s Patent 2,993,554 WELL SOUNDING GUN Billy H. Towell, Bellaire, and Robert B. Heath, Houston, Tex., assignors to Texaco Inc., a corporation of Delaware Filed May 31, 1956, Ser. No. 588,533 3 Claims. (Cl. 181-.5)
This invention relates to a cartridge firing device for use with acoustic well sounding equipment employed for acoustically determining the depth from the surface to the fluid level in the well.
Well sounders of the present type generally comprise an assembly which includes pressure-proof pipes, fittings, and instruments which are mechanically connected to the well in the test. Such instruments essentially include a cartridge firing device, microphone, recorder, wadding catcher and bleeding valve.
Typical well sounders record directly on chart paper sound pulses produced upon the firing of a blank cartridge in the annular space between the tubing and casing of a well. Sound pulses are reflected by tubing collars, tubing catchers, and any other constriction or enlargement of the gas column above the fluid. The depth to the fluid can be determined by multiplying the number of tubing joints by the average tubing length.- The distance to the fluid is often many thousands of feet and the sound pulses generated by the cartridge in the firing device or gun must be suflicient to travel the distance to the fluid and back to the microphone without nullifying attenuation.
The problem of firing a cartridge into a producing well to create sound therein is somewhat unique because pressures as high as 15-00 lbs. or more per square inch are frequently encountered and the moving parts of the firing device must be sealed against such pressures and against contamination by corrosive well gases, oily fumes and powder fumes which are forced into it by said pressure. The firing device or gun must be designed to cope with this unique problem and such a device should also include adequate safety means to protect the equipment from premature firing of the cartridge.
Accordingly, an object of the present invention is to provide an improved firing device in which blank cartridges can be exploded into a well and which is sealed to prevent contamination by corrosive well gases and powder fumes from the exploded cart-ridge. Another object of the invention is to provide a firing device embodying safety features which prevent the premature firing of the cartridge as when the device is being prepared prior to firing. A still further object of the invention is to provide a firing device having a barrel designed to obtain a much greater efliciency from the cartridge which is fired. Another object of the invention is to provide an improved well-sounding gun which is safer, easier to load, and easier to fire.
In order to accomplish the foregoing and other objects in accordance with this invention, there is provided a cartridge firing device for use with acoustic well-sounding equipment comprising a barrel having a choke in the exit end thereof whereby greater efficiency from the exploded cartridge is obtained, means to detonate said cartridge, and means to connect said firing device to said well sounding equipment. It has been realized that chokes in shot gun barrels to concentrate the pellets from fired shot gun shells are well known. However, a novel effect is obtained by using a choke in the barrel of a firing mechanism for well-sounding to modify the shape of the sound pulse to obtain a lower frequency. This is extremely advantageous since a 'low frequency pulse will travel much further than a relatively high frequency pulse. The means for detonating the cartridge comprise a breech block coupled to the barrel, a firing pin mounted in the coupled end of the breech block and in axial alignment with the barrel, a spring loaded hammer mounted in the breech block, said hammer biased toward said firing pin and in axial alignment therewith, said hammer having a cocking catch and a safety catch along its length, and a spring biased sear pin mounted in the breech block and urged toward the hammer whereby it is engageable with the cocking catch and the safety catch, the safety catch being positioned at a lesser distance from the cocking catch than the distance between the fining pin and the hammer when the sear pin is engaged in the cocking catch whereby the sear pin will engage the safety catch when the hammer rebounds after hitting the firing pin.
Packing means in the form of 0 rings are associated with said firing pin to prevent the entrance of corrosive gases into the breech block.
The invention also includes the method of determining the depth from the surface to the fluid level in a well comprising creating low frequency sound pulses by firing a cartridge into a well from a firing device having a choked barrel, converting reflected sound pulses to electrical pulses, and recording said electrical pulses.
The invention will be further understood by reference to the accompanying drawing wherein FIG. 1 represents a side sectional view of the firing device and FIG. 2 is a view showing the well sounding equipment connected to a well.
The device is connected to the remainder of the wellsounding equipment represented by pipe 2 by means of an internally threaded barrel housing 4, the threaded connection being of 'sufficient strength to withstand the high pressure of the well. The barrel 6 is coupled to the breech block 8 by means of internally threaded union nut 10 which engages the external threads on barrel housing 4. Nut 10 has an internal flanged portion 12 which is adapted to fit over the breech block 8 and engage the extending flanged portion 14 at the coupling end thereof. Within an internally threaded cavity 15 at the coupling end of breech block 8, firing pin guide 16 is threadedly secured. The firing pin 17 with firing-pin head 18 is reciprocably mounted in the firing pin guide 16 and firingpin head 18 is normally urged into a stop position with the shoulder of the chamber opening 19 in the breech block 8. Coil spring 22 which surrounds the firing pin causes this biased engagement of firing-pin head 18 with the shoulder of the chamber opening 19. O-rings 23 and 24 are provided around the firing pin and firing-pin guide, respectively, to prevent the escape of the high pressure well gases and also to prevent corrosive powder fumes and corrosive well gases from entering the firing mechanism. O-ring 23 is held in position by O-ring retainer 26 which, in turn, is fastened to the firing pin guide 16 by means of screws or the like at 28.
Within the breech block 8 a reciprocably mounted hammer 20 is normally urged toward the firing pin by spring 32. The spring 32 is confined between the flange 34 protruding laterally from the hammer 20, at one end, and a spring retainer 36 fastened to the breech block 8 by screw means 37 or the like at its other end. The hammer 20 is provided with a handle 30 to facilitate cocking.
Extending perpendicularly from and through the breech block 8 is sear pin 38 which is urged into engagement with the side of hammer 20 by means of coil spring 40 which is confined between a flanged portion 41 on the sear pin and sear pin retainer 42. The scar pin 38 is usually provided with a ring through hole 44 to facilitate firing. Hammer 20 has a cocking slot or catch 46 which is seen engaged with end 48 of the sear pin 38. A safety catch or slot 50 is provided in hammer 20 at a lesser distance from the cooking catch 46 than the distance between "firing pin 17 and hammer 20 when sear pin 38-is in engagement with cocking catch "46. A channel portion 52 is provided in the hammer 20 between catch 46 and extending slightly past catch 50 to maintain the sear pin in the correct position on the hammer relative to the catches 46 and 50. The hammer 20 when released from the cocked position will travel fast enough [to prevent the sear pin 38 from engaging safety cateh 50. However, after hammer 20 strikes firing pin 17, it will rebound slightly and the sear pin 38 will engage safetycatch 50 at this point. This holds the hammer 20 safely away from the head 18 of firing pin -17, thereby preventing the accidental detonation of a new cartridge.
Cooking is accomplished by pulling sear pin 38 out of safety position 50 and then pulling hammer 20 out until sear pin 38 engages in cocking slot or catch 46.
Barrel 6 is provided with a choke or restricted portion at 54. This combination of barrel and choke permits a surprisingly greater eificient utilization of the energy from the cartridge 68 to be used by modifying the sound pulse to a lower frequency when the cartridge is fired. 'This allows the use 'of a cartridge containing less powder and consequently reduces the expense and ultimate corrosion caused by excessive smoke from a cartridge or shell burning more powder. In the preferred embodiment, the firing device is designed to accommodate a .410 gauge shotgun shell and the barrel length is about 12 inches long. The choke is of an inch and extends over the last A inch of the exit end of the barrel.
As seen in FIG. 2, the well sounding equipment is attached to the well at valve 60 by means of a bushing and union. A wadding catcher 62 is placed in a section of pipe below the exit end of barrel 6 to prevent the wadding from the cartridge entering into the well. Bleeder valve 64 is provided to permit release of pressure in the well sounding equipment after valve 60 is closed so that the firing device can be removed.
Microphone 66 converts the sound pulses to electrical impulses and transmits them to the recorder.
Obviously, many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof and, therefore, only such limitations should be imposed as are indicated in the appended claims.
1. A cartridge firing device for use with acoustic well sounding equipment comprising a barrel, a breech block coupled to said barrel, a firing pin mounted in the coupled end of the breech block and in axial alignment with 'said "barrel, a 'spring'loaded hammer mounted'in the breech block, said hammer biased toward said firing pin and in axial alignment therewith, said hammer having a cooking catch and a safety catch along its length, a spring biased sear pin mounted in said breech block and urged toward said hammer whereby it is rengageable with said cocking catch and said :safety'catch, said safety catch being positioned at a lesser-distance from the cooking catch than the distance between said firing pin and said hammer when said sear pin is engaged in said cocking catch whereby the sear pin will engage the safety catch when said hammer rebounds after'striking said firing pin, and means to connect said firing device to said well sounding equipment.
2. A cartridge firing device as described in claim 1 wherein said hammer has a channeled portion along its length between said cocking catch and said safety catch and extending slightly past said safety catch whereby the end of said sear pin will ride in said channel when the device is fired.
3. A cartridge firing device for use with acousticwell sounding equipment comprising a barrel, a breech block coupled to said barrel, a firing pin mounted in thecoupled end of the breech block and in axial alignment with said barrel, packing means associated with said firing pin to prevent the entry of corrosive gases into said breech block, a spring loaded hammer mounted in the breech block, said hammer biased toward said firing pin and in axial alignment therewith, said hammer having a cocking catch and a safety catch along its length, a spring biased sear pin mounted in said breech block and urged toward said hammer whereby it is engageable with said cocking catch and said safety catch,
said safety catch being positioned at a lesser distance from the cocking catch than the distance between said firing pin and said hammer when said searjpin is engaged in said cocking catch whereby the sear pin will engage the safety catch when said hammer rebounds after striking said firing pin, and means to connect said firing device to said well sounding equipment.
References Cited in the file of this patent UNITED STATES PATENTS 570,458 Coston Nov. 3, 1896 602,422 Batcheller Apr. .-19, .1898 1,422,865 Jobson July 18, 1922 1,772,656 Abbott Aug. 12, 1930 2,232,476 Ritzmann Feb. '18, 1941 2,560,911 Wolf July 17, v'1