US2344297A - Deep well firing mechanism - Google Patents

Description

March 14, 1944. GREENE DEEP WELL FIRING MECHANISM Filed Aug. 3, 1940 2 Sheets-Sheet l INVENTOR.

HOWARD H.GREE.NE

; ATTORNEY.

March 14, 1944. GREENE 2,344,297

DEEP WELL FIRING MECHANISM Filed Aug. 3, 1940 2 Sheets-Sheet 2 fi if "39 l n W if 3111 mu L. 5 4 2 $21-25 FIG 6 F167.

'INVENTOR.

HOWARD HGREENI:

Patented Mar. 14, 1944 UNITED STATES PATENT OFFICE The invention relates to the shooting of deep well casing, tubing, or drill pipe, preferably at Joints, as may be required, for example, when and through the present device in the position it is desired to recover casing from an abandoned well and the entire string of pipe cannot be withdrawn. Under such circumstances, the pipe is shot at a substantial distance from its lower end and an effort made to withdraw the pipe to a certain level. If this eflort is unsuccessful, the pipe is again shot at a higher level and etfort made to withdraw the pipe above that level, and this operation is repeated until the pipe can be withdrawn.

It has been customary to explode the shots electrically, which necessitates a pressure-resisting seal type of detonator and wiring running to the well head. Also it has been customary to explode the detonator by percussion caps operated by a weight dropped into the same,, the velocity and effectiveness of the dropped weight being subject to fluid in the well and other uncertain factors. Another method of firing a percussion cap has been to drop a length of pipe down a torpedo line until it strikes a firing device hammer. This pipe may cut the line during its descent or the pipe may catch on the casing during its descent, and it may then be necessary to raise the torpedo, in which case the pipe may become dislodged at a point near the top of the well and explode the torpedo at an undesired and, possibly, a dangerous level.

One object of the present invention is to fire the shot by a direct upward pull on the shot can after the same has been lowered to a desired level and irrespective of any support for the device in the well, this object being attended by the incidental object of eliminating the drop-v ping of a pipe or other weight upon a firing pin to eflect discharge of the shot.

Another object of the invention is to safeguard the device against discharge except when desired and to make it possible to remove the device from the well, it necessary, without danger oi accidental explosion and injury to the casing at a higher level than desired-or injury to the operator.

Another object oi. the invention is to secure the safety of everyone handling the device prior to lowering the same into the well.

These and other detail objects of the invention as will appear in the following description are attained by the structure illustrated in the,

accompanying drawings, in which- Figure 1 is a longitudinal section through adjacent well casing members and their coupling which it assumes after having been lowered into the well and Just prior to being raised to fire the detonator.

Figure 2 is a longitudinal section through the apparatus taken on the line 22 of Figure l but drawn on an enlarged scale, the parts being in the same relative positions indicated in Figure 1.

Figures 3 and 4 are horizontal sections taken on the corresponding section lines of Figure 2. Figure 5 is a section, similar to Figure 2, through the firing unit and showing the parts in the positions assumed after the apparatus is raised by its suspension line from the position shown in Figures 1 and 2 and just prior to the instant oi. discharge.

Figured isa similar section showing the parts with the firing hammer released and actuating the firing pin.

Figure '7 is a similar section showing the parts in the position assumed either intentionally or accidentallyunder conditions when the device will not be fired and may be removed from the well without injury to the casing or the operator.

The apparatus includes an elongated can I of substantial diameter and a barrel 2 forming the housing of a firing mechanism unit. Barrel 2 is of comparatively small diameter and is positioned axially of can I. The lower end of can I includes a collar 3 threaded onto the lower portion of barrel 2. A nut I, also threaded onto barrel 2, looks the can and barrel in the positions shown. A ball 5 on the upper end of can I is received in a hook 8 on the lower end or the suspension line I by which the device is lowered into the well and operated to discharge the dynamite, nitroglycerin, or other explosive E packed in can I about barrel 2.

A detonator cartridge III is screwed into and forms a closure for the upper end of barrel 2 and includes a. chamber for the detonating material D and a seat for the detonator percussion cap C. Seated against the shoulder formed by the lower end of cartridge I0 is a collar II slidably receiving a firing pin I2 having a shoulder I3 atits lower end. A spring I4 compressed between shoulder I3 and collar II tends to hold the firing pin in the position indicated in Fi8- ure 5, the key I5 limiting the spring-thrust movement of pin I2.

Rods l6 have their upper ends secured to collar II and hold collars I'|, I8, I9 and '20 in other parts in barrel 2, the cage being held against movement in the barrel by a screw 3|! engaging collar l3.

A firing hammer 2| is slidably'received in collars l1 and i3 and has a shoulder "at its upper end. a relatively strong spring 23 is compressed between collar I1 and shoulder 22, and it is the compression and release of this spring, as explained below, which thrusts hammer 2| against firing pin |2 to discharge cap C. The lower portion of hammer 2| terminates in an annulus 24 having beveled upper and lower faces.

A plunger 25 is slidably received in collars l3 and 20 and is provided with a key. 25 forming a seat for a plunger spring 21, the other end of which is seated on collar 20. Spring 21 thrusts plunger 25 upwardly until key 25 engages the lower face of collar I3. I

A pair of spring arms 28 extend upwardly from plunger 25 terminating in inturned fingers 23 thrust towards each other by the inherent resiliency of the arms so as to grip the lower end of hammer 2| between them when the parts are in the positions shown in Figures 1 and 2.

The lower end of plunger 25 is secured to an inverted conical member 3| to which are attached a plurality of spring wires 32 extending upwardly and outwardly for engagement with the well casing W and slidable freely along the latter as the apparatus is being lowered into the well but adapted to engage a joint in the casing well, as indicated at J in Figure 1, when the apparatus is raised from a lowered position. The securing of plunger 25 and member 3| may be effected by threading the lower end of plunger 25 and screwing a nut or collar 33 onto the same to form a shoulder and then screwing the projecting end of plunger 25 into a nut or boss 34 forming a part of member 3|.

Operation.ther elements providing safety features will be referred to below but the principal operation of the device will be fully understood from consideration of the parts described above.

The device is lowered to the desired level in the well and then raised to engage wires 32 with the nearest casing joint J, whereupon spring wires 32, member 3|, plunger 25, including spring arms 28, remain stationary. Further pull on lift line 1 causes the can I, barrel 2, and the parts enclosed thereby, other than plunger 25, to be raised except that firing hammer 2| will be held temporarily by spring fingers 29 until the parts assume the positions shown in Figure in which the fingers have slid almost to the edge of annulus 24 and the firing hammer spring 23 has been compressed, th hammer moving away from the head of firing pin l2 and spring H of the latter having moved the .pin to its lowermost position. The hammer is now cocked.

Further pull on line 1 causes fingers 23 to'slip off of annulus 24 releasing the hammer, whereupon its spring 23 drives the hammer against firing pin i2 moving the pin against the relatively slight resistance of its spring |4 striking the cap C to initiate the discharge.

Safety devices.--There can be no blow on pin l2 or cap C so long as the hammer is in the position shown in Figure 2, and it is firmly held and up to the moment of its being lowered into the well, plunger 25 and barrel 2, are held against relative movement by a safety pin 35 (Figure 1) extending transversely through plunger 25 and a nut 33 screwed onto the lower end of barrel 2. It will be understood that this pin can only secure the associated parts against movement when they are in the positions shown in Figures 1 and 2.; i. e., when the firing hammer is elevated. Hence, there is no possibility of the removal of pin 35 releasing the plunger or the hammer from -a cocked position in which their respective springs would move the plunger and barrel relative to each other. In other words, pin 35 merely holds barrel 2 and elements 25, 3| and 32 against rela tive movement which is necessary to fire the device.

When the device is lowered into the well, there is a possibility that hook a would become disengaged from ball 5 accidentally and before detonation was desired. It is possible also that desired detonation or explosion could be'prevented because of defective explosives, detonator, or for other reasons, and it would be desirable to remove the device from the well. Under such circumstances it would be important to prevent accidental discharge of the device by upward movement of the apparatus through the well.

To secure this objective, there is provided a safety pawl 31 pivoted to collar l1 and provided with a spring 38 (Figure 7) which tends to thrust the pawl towards hammer 2| so that it may engage one of the peripheral shoulders 33 formed on the hammer, which would prevent the hammers striking of the firing pin and discharging the detonator. A .pin 40 on pawl 31 extends laterally through an opening in the side of barrel 2 and has a transverse aperture near its outer end which receives a safety wire 4| bearing against the outer face of the barrel, and normally holding pawl 31 in non-functioning position, as shown in Figures 2, 5 and 6. A tie 42 connects safety wire 4| with suspension line I.

Assuming that bail 5 and hook 5 become disengaged accidentally and the apparatus drops, tie 42 is immediately tightened and safety wire 4| is jerked from pin 40 releasing pawl 31 so that it may function as shown in Figure 7 if firing barrel 2 is subsequently pulled into firing position. A supplementary tie 43 between line I and bail 5 is provided with sufficient slack that it cannot checkthe downward movement of the apparatus until after tie 42 has functioned as described. Assuming that the operator attempts to discharge the device and for some unknown reason there is no explosion and it becomes necessary to remove the apparatus from the well and inspect it or lower another device, the operator first intentionally disengages ball 5 and hook 5 by lowering the device until it strikes the bottom of the well or an obstruction which takes the weight of the apparatus oil of line 1. Having disengaged hook 5 and bail 5, the line I is raised, immediately tightening tie 42 and releasing pawl 31.

'Further pull on line 1 will raise the apparatus until wires 32 strike an obstruction, whereupon the plunger and firing mechanism will be operated as described above under Operation except that the spring-impelled movement of hamagainst movement upwardly from this position v mar 2| will be checked by pawl 31, as indicated in Figure 7. Further and intensified pull on line 1 will double back the relatively weak wires 32 and the device may be removed from the well.

irrespective of frictional contact with the side of I Obviously the details illustrated may be changed substantially and some of the features may be omitted, if desired, without departing from the spirit of the invention, and the exclusive use of all modifications which come within the scope of the appended claims is contemplated.

What is claimed is:

1. In a deep well firing device, a member having upwardly and outwardly inclined yielding elements for sliding freely down a well but resisting movement of said member upwardly in the well, a frame slidable relative to said member, a firing hammer movably mounted on said frame, a spring having an upwardlyfacing seat on said frame and thrusting said hammer upwardly, a spring having an upwardly facing seat on said frame and supporting said member, jaws on said member yieldingly engaging said hammer to hold it against the initial thrust of said hammer spring but releasing their hold on said hammer when said hammer spring is sufficiently compressed, a detonator carried on said frame and adapted to be exploded by said hammer when said hammer is released from said jaws, and means for lifting said frame in the well while the well-engaging elements of said member are functioning.

2. A device as described in claim 1 in which the frame comprises an elongated tubular barrel enclosing the hammer, springs and the hammer engaging jaws, and the member carrying the well-engaging elements is partly received in the barreLand partly projects from one end of the barrel and the detonator is mounted on the other end of the barrel, there being an elongated container surrounding said barrel and the lower portion of said detonator and fixed to said barrel and packed with explosive about said barrel.

3. In a deep well firing device, a unit containing explosive material and arranged for direct attachment to a suspension line whereby the unit may be lowered into a well, said unit including a detonator flreable by impact, a spring seated on said unit, another unit supported on said spring'unit and including elements for engaging the side of the well to resist movement of the latter-mentioned unit upwardly in the well, a firing hammer associated with said detonator, another spring seated on said first-mentioned unit and thrusting said hammer in one direction, and means on said second-mentioned unit operable by lifting said first-mentioned unit after said elements have engaged the well side to cock the hammer in the opposite direction and compress the hammer supporting spring and then to release said hammer for firing operation by its spring.

4. A device as described in claim 3 which also includes a safety member on the hammer carrying unit movable into contact with said hammer to check the discharge movement of thelatter, a spring for so moving said member, a detent engaging said member against the thrust of said spring, and selective means for withdrawing said detent by the device suspension line.

5. A device as described in claim 3 which includes a detachable hook connecting the detonator unit to the suspension line, a supplemental lost motion device connecting the detonator unit and the suspension line and functioning whenthe hook is detached from the detonator unit, there being a spring-actuated safety member for preventing the hammer from firing, means for operating said safety member including a holding pin for restraining the safety member spring, and a tie between said pin and the suspension line of such length as to be drawn taut and thereby withdraw said pin from said member upon detachment of said hook and taking up a substantial portion of the lost motion in said device but before all the lost motion is taken up in said device.

6. In a deep well firing device, a detonator, a spring-actuated hammer therefor, means operable to cook and fire said hammer by lowering the device into a well and then raising a portion of the device, and means selectively operable from the well head for preventing the hammer from firing when it is desired to raise the device from the well without discharging the detonator.

7. In a deep well firing device, a detonator, a spring-actuated hammer therefor, means operable to cock and fire said hammer by lowering the device into a well and then raising a portion of the device, and structure for preventing the firing of the device at the will of the operator after the device has been lowered into the well, said structure comprising a member movable into position to check the hammer inits movement from cocked position towards the detonator, a spring for so moving the member, a latch normally holding the member retracted against the thrust of its spring, and means operable from the well head for withdrawing the latch from the member.

8. In a deep well firing device, a unit adapted to be detachably engaged to the lower end of a suspension line, a detonator associated with said unit, a hammer movable on said unit into cocking and discharging positions to fire the detonator by impact, a unit movable relative to said first-mentioned unit and-including elements for engaging the side of the well when the device is raised by the suspension line, elements on said second-mentioned unit frictlonally engaging the hammer and moving the same to cocking position upon predetermined relative movement of said units and releasing the hammer for discharge movement upon further relative movement or said units, a spring-actuated member for checking the discharge movement of the hammer, a latch slidable on said first-mentioned unit for holding said member inactive, and a slack line between said latch and the lower end of the suspension line for withdrawing the latch from latch holding position upondisengagement of the suspension line from the first-mentioned unit.

HOWARD H. GREENE.

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