US3199594A

US3199594A - Explosive jar

Info

Publication number: US3199594A
Authority: US
Inventors: Myron M Kinley
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-01-08
Filing date: 1962-01-08
Publication date: 1965-08-10
Anticipated expiration: 1982-08-10

Description

1965 M. M. KlNLEY V 3,199,594

EXPLOSIVE JAR Filed Jan. 8, 1962 4 Sheets-Sheet l 52?" Mrs? Z i Z BY -i- I i #vM/M J2 z M. M. KINLEY Aug. 10, 1965 EXPLOS IVE JAR 4 Sheets-Sheet 2 Filed Jan. 8, 1962 Myra/7 M /K//7/e5 INVENTOR.

HTTOR/VEVJ:

M. M. KINLEY Aug. 10, 1965 EXPLOSIVE JAR 4 Sheets-Sheet 3 Filed Jan. 8, 1962 Myra/7 M /(//7 /e IN VEN TOR.

ATTO/P/VEKS.

Aug. 10, 1965 M. M. KlNLEY 3,199,594

EXPLOSIVE JAR Filed Jan. 8, 1962 4 Sheets-Sheet 4 Myra/2 M /f//7 /ey INVENTOR.

W4 4i M United States Patent 3,199,594 EXPLGSEVE EAR Myron M. Kinley, Chichasha, (thin, assign-or to .iohn C. Kinley, Houston, Tex. Filed inn. 8, 1952, Ser. No. 166,734- 9 Qlaims. (Cl. res-es This application is a continuation-in-part of application, Serial No. 44,925, filed July 25, 1960, now abandoned.

This invention relates to new and useful improvements in devices for imparting a jarring or impact force, and particularly to an explosive jar or tool for imparting a jarring force in a well.

Mechanical jars and hydraulic jars have previously been the only types of jars or jarring devices available for imparting longitudinal jarring strokes in well operations. Although mechanical jars which may be lowered on and operated by a wire line are used, they generally cannot deliver a very substantial jarring blow; therefore, most jars heretofore known are lowered into an oil well or the like on well tubing or pipe string which involves the usual diiliculties associated with the connecting and disconnecting of the sections of the string during the running in and withdrawal of the jars from the well. In the deeper wells, such difliculties are, of course, increased. Furthermore, in some instances, even the mechanical and hydraulic jars which are lowered on the tubing string do not deliver an adequate enough jarring blow to release a stuck fish, and then the time required for the connection and disconnection during the lowering and raising of the jar in the well is completely lost.

An object of the present invention is to provide a new and improved jarring device capable of delivering a longitudinal jarring blow and which is adapted to be lowered in a well or the like on a wire line or similar flexible support.

An important object of this invention is to provide a new and improved jar which is actuated by the firing of an explosive to provide an increased jarring or impact force as compared to prior known mechanical and bydraulic jars.

An important object of this invention is to provide a new and improved jar which is actuated by the firing of an explosive to provide an increased jarring or impact force as compared to prior known mechanical and hydraulic jars, which jar incorporates means for relieving the pressure in the jar to inhibit excessive build up of pressure therein.

A further object of this invention is to provide a new and improved jarring device which is adapted to have diiferent jarring heads mounted therewith for performing various operations with the device such as jarring a stuck fish loose in a well, taking a lead impression of the upper end of a stuck fish in a well, and puncturing a bull plug at the lower end of a pipe string.

A still further object of the present invention is to provide a jar which obtains a more accurate impression Patented Aug". 3%, 1965 "ice and partly in section, of the upper, intermediate, and lower portions, respectively, of the preferred form of the explosive jar of this invention;

H6. 2 is a cross-sectional view, taken on line 22 of FIG. 1A;

FIG. 3 is a cross-sectional View, taken on line 33 of PEG. 1C;

FIG. 4 is a vertical sectional view illustrating a modified form of the lower portion of the explosive jar or tool of this invention.

FIG. 5 is a vertical sectional view of another modified lower portion of the jar or tool of this invention, shown in position for puncturing a bull plug;

FIG. 6 is a vertical sectional view of another modified lower portion of the explosive jar or tool of this invention; and

PEG. 7 is a vertical sectional view of still another modified lower portion of the explosive jar or tool of this invention.

In the drawings, the letter B designates generally the hollow or tubular body of this invention which is preferably formed of a metal such as steel and which is also preferably formed in several parts, including a main body portion it), a lower body portion ii, an upper body portion 12, and an upper body adapter 14. As will be explained in detail, the body B includes a hollow chamber or bore lilo for receiving an explosive E such as an ordinary gun shell or bullet. Such explosive E is adapted to be fired or detonated by a manipulation of the wire line W or other flexible line upon which the tool is supported and lowered and withdrawn in an oil well or other similar type of location. The explosion from the explosive E imparts a longitudinal movement to a force transmitting member or hammer H which is supported within the body B. Such movement of the hammer H with respect to the body B is transmitted to an anvil A or other jarring member for imparting a jarring force thereto which may be transmitted in various ways as will be more fully explained. Thus, with the tool or jar of this invention, a jar is obtained by means of an explosion within the body of the jar or tool and such explosion provides an extremely great force for producing a longitudinal jarring action which is far greater than the longitudinal jarring forces heretofore known or obtained with conventional mechanical and hydraulic jars. Furthermore, the high force of this device for the jarring action is obtained even though the device is lowered on a wire line or other flexible line, and therefore the tool can be rapidly lowered and raised in a well while at the same time obtaining an extremely hard jarring force with the tool or jar of this invention.

Considering the invention more in detail, the body portion 19 has internal threads Nib formed thereon which are in threaded engagement with external threads 11b on the lower body portion 11 for thereby connecting the main body portion it and the lower body portion 11 together. Of course, it will be appreciated that other suitable means for connecting such body portions 10 and 13. together may be provided and in some instances they may be made integral. The bore 11a of the lower body portion 11 is in alignment with and forms a continuation of the bore ltia of the main body portion 1%. A shear disk 2 3' formed of brass or a similar relatively soft material capable of being sheared is positioned betweenthe upper end of the lower body portion 11 and an annular lateral shoulder 1153c formed in the bore Min of the main body portion 10. Thus, when the threads 10b and 11b are interengaged and are threaded up tightly, the end 110 tightly engages the shear disk 28 to hold same in contact with the shoulder ltic. Such shear disk or plate supports a longitudinally movable hammer or piston H which is positioned in the bore 10a of the body 19. A wadding of rubber or other material 21 is positioned between the explosive E and the upper end of the hammer or piston H for keeping the explosion gases from leaking past the hammer H when the explosion or detonation of the explosive E occurs.

As previously mentioned, the explosive E may be in the form of an ordinary gun shell or bullet and as shown in FIG. 1B, the explosive E includes a shell 23 which has powder 24 or other explosive material therein. A percussion detonator cap 25 is mounted in the upper end of the shell 23 for detonating or firing the powder when the cap 25 is contacted by a firing pin 27. The shell 23 has an annular flange 2311 at its upper end and a closure head 232; at its lower end. The flange 23a rests upon an annular laterally extending shoulder or surface 19d of the main body portion 16.

The shell 23 is retained in position on the flange 19d by the engagement of the lower end 14a of the body adapter 14 with the upper end of the shell 23;. Such contact is maintained due to the threaded connection between the main body portion 16 and the body adapter M which is provided by the interengaging threads 102 on the body portion 10 and external threads lab on the body adapter 14. Of course, any other suitable connection means between the bcdy portion 10 and the body adapter 14 may be provided, and in some cases, they may even be integral.

The adapter 14 is provided with a lower tapered lower bore 14c in which the firing pin 27 is positioned. Such pin 27 is also tapered so as to have a larger diameter at its lower portion than at its upper portion. In that way, when the explosive or shell E is detonated, the firing pin 27 will be prevented from being blown or discharged upwardly in the bore 14c, and therefore the pressures or gases of the explosion will be confined below the firing pin 27. The body adapter 14 also has an upper bore 14d which is cylindrical and which forms a continuation of the bore 14c. A vent hole or holes 142 is provided from the bore 14d to the exterior of the tool to prevent the entrapment of fluid or gas below a firing pin extension or rod 3t) positioned in the bore 14d. Thus, as will be more fully explained, the extension or rod 39 is longitudinally movable within the adapter 14 for imparting an impact to the firing pin 27. The vent or vents 14c permit the escape of any gas or fiuid below such firing pin extension or rod 30 during the downward movement thereof, which as explained, prevents the entrapment of such fluid or gases and therefore prevents a fluid lock of the extension 30 in the bore 1%. Actually, the pin 27 and the extension 30 could be made of one piece since they move together, but for ease of manufacture and assembly, they are made in the two pieces as illustrated. The upper end of the body adapter 14 is provided with an annular groove 14] and an annular downwardly extending surface 14g to provide a fishing neck for engagement by any conventional fishing tool when the upper body portion 12 has been separated from the body adapter 14-, as will be more fully explained.

Under normal conditions of operation, the body portion 12 is connected to the body adapter 14 by means of interconnecting shear pins 32 of brass or other similar shearable material. As best seen in FIG. 2, such pins extend laterally through the body adapter 14 and project into openings 12a formed in the upper body portion 12. Such pins 32 are sheared or severed by an upward pull on the upper body portion 12 with a sutficient force to move the body portion 12 relative to the body adapter 14. This would not normally occur during the lifting of the tool, but it could be accomplished intentionally by an upward jar as will be explained. The body portion i2 has a bore 12b into which the body adapter 14 extends to make the connection previously described with the shear pins 32. Other types of shearable connections may, of course, be utilized to connect the body portion 12 and the body adapter 14 together. A vent hole or holes 12c is provided in the wall of the body portion 12 for establishing fluid communication between the interior or bore 12b of the body portion 12 and the exterior thereof to prevent entrapment of fluid or gas below a firing head 35 which is mounted with the body portion 12 for longitudinal movement with respect thereto.

The firing head 35 is provided with a contact section 35a which has a diameter no greater than the diameter of the bore 14d so that it can enter the bore 14d for striking or hitting the upper end of the firing pin extension 30. During the running in of the tool in a well, the firing head 35 is positioned as shown in FIG. 1A so that the contact section 35a is above the upper end of the extension 30 and out of contact therewith. Such position of the firing head 35 is maintained by the engagement of an annular shoulder 35b on the head 35' with a corresponding annular shoulder 12d formed in the bore of the body portion 12.

A metal shear pin 36 formed of brass or other similar material extends through the firing head 35 and rests on a support washer 37 which in turn rests upon a lateral shoulder 122 formed on the body portion 12. Thus, under normal conditions, the firing head 35 is prevented from moving longitudinally in either direction with respect to the body portion 12, but when the pin as is sheared or severed, then the firing head 35 may move downwardly with respect to the body portion 12 for contacting the firing ,in extension 30 which imparts movement to the firing pin 27 for detonating or firing the explosive E.

The firing head 35 is connected to a connector sub 41) by any suitable means such as internal threads 40a which are in threaded engagement with external threads 35c at the upper end of the firing head 35. A lock pin or pins 41 extends through suitable openings in the firing head 35' and the connector sub for preventing an inadvertent release of the threads 35c and 43a during the use of the tool. The sub 4i) has a reduced diameter area 461: and an annular flange 40c which is downwardly inclined to provide a fishing neck for engagement by a conventional fishing tool in the event the portion of the tool above the sub 44 is released during the use of the tool in a well.

The upper end of the connector sub 49 has external threads 4001 formed thereon which are in threaded engagement with internal threads 45a formed at the lower end of a weight 4-5. The weight 4-5 is provided in connection with the tool in the event it is necessary to provide additional weight to the body B to prevent or limit the upward travel of the body B in the well when the explosion of the explosive E occurs. In other words, when the explosion of the explosive E occurs, there will be a tendency for the hammer H to move downwardly and the body B to move upwardly. However, if the weight of the body B together with the weight of the weight member 45 are sufficient to prevent the body B from moving upwardly, all of the downward force, or substantially all of such force, will be transmitted to the hammer H for a downward movement thereof.

Such weight 45 may take numerous forms, but as illustrated, such weight 45 is merely an elongate bar of solid steel or other metal which is threaded to the connector sub 40 as explained. The upper end of the weight 45 is preferably connected to a conventional wire line mechanical jar J in any known manner. Such jar J is of known construction and merely operates to provide for a mechanical jar upon the manipulation of the wire line W connected at its upper end. The jar J is of the type which provides both an upward jar and a downward jar when desired.

The anvil A may take numerous forms and may serve numerous purposes. One form of the anvil A is shown in FIG. 1C and other possible forms of the anvil are illustrated in FIGS. 4, 5, and 6, as will be explained.

Considering the anvil A of FIG. 1C, such anvil or jarring member A is so constructed that it is adapted to jar a stuck choke or other fish in a well. The anvil A is mounted for limited longitudinal movement within the enlarged bore 11d of the lower body portion 11. The anvil A has an upper annular surface 559 which is adapted to contact a lateral shoulder lle in the bore of the lower body portion 11 so that the upward movement of the anvil A is limited in the body portion 11. It should also be noted that the upper end of the anvil A is positioned a considerable distance below the lower end of the hammer H. Such spacing provides for the travel or stroke of the hammer H to develop the momentum and the jarring force prior to the contact of the hammer H with the anvil A. A vent hole or holes 11 are provided in the wall of the lower body portion 11 to prevent the entrapment of fiuid or gases below the hammer H as it travels downwardly within the body portion 11 during the jarring stroke.

The anvil A also has a lower annular shoulder 51 which is adapted to contact the upper end of an annular split nut 52 which is threaded with its external threads 52a into internal threads llg of the lower body portion 11. The lower end 53 of the anvil A shown in FIG. 1C is recessed to facilitate engagement and contact with the stuck object or choke in the well to be loosened by the jarring action with the jar of this invention, but various configurations and shapes may be provided for such lower end 53 as will be understood by those skilled in the art. in order to retain the various threaded sections together, metal lock rings may be used such as are indicated at 55 and 56 with bent flanges or projections in the known manner.

In the use or operation of the jar or tool of this invention with the anvil A at its lower end, the tool or jar is lowered in a well on the wire line W which may be a piano wire or other similar flexible line. During such running in of the tool or jar of this invention, the firing head 35 is maintained in the position shown in FIGURE 1A and the hammer H is maintained in the position shown in FIGS. 13 and 1C. The shear pin 36 maintains the firing head 35 in its inactive position while the shear disk 2%? maintains the hammer H in its inactive position. The jar or tool of this invention is lowered until the lower end 53 of the anvil A is in contact with the choke or other stuck object or fish to be jarred with the tool or jar of this invention. Then, the wire line is manipulated to operate the wire line mechanical jar I in the known manner for imparting a sulficient jarring force to the weight 45 and the connector sub 46 to shear the pin 36. When the pin 36 is sheared or severed, the firing head 35 moves downwardly, and the contact portion 35a engages the upper end of the firing pin extension 39 to impart a downward force to such firing in extension 39. The downward force of the pin extension 33 is transmitted to the firing pin 27 and the impact from the pin 27 on the cap 25 causes a detonation or firing of the explosive 24 within the shell 23. Such explosion creates a terrific pressure as is well known and since such pressure is conihied within the bore 1%, the explosion force is transmitted downwardly against the head of the hammer H. Such force acting on the hammer H is sufiicient to immediately shear the disk 2% and to cause the hammer or piston H to move rapidly downwardly through the bore 11a of the lo er body portion 11 and into contact with the upper end of the anvil A. As previously pointed out, the weight of the body B and any weight such as the weight 45 thereabove prevents the upward movement of the body B during such explosion. The jarring force transmitted to the anvil or jarring member A is thus imparted to any object such as a stuck choke or fish below the anvil A and engaged thereby. The amount of jarring force thus obtained is substantially greater than is possible 6 with the known types of mechanical and hydraulic jars used in wells.

In the event the jar fails to operate properly or becomes stuck, the shear pins 32 may be sheared by an upward jar with the wire line mechanical jar I so as to pull the upper body portion 12 upwardly away from the body adapter 14, leaving the fishing neck 14g exposed for engagement by a conventional fishing tool. In some instances, the threads 45a and 4M may be separated to expose the fishing neck 4G0 for engagement by a fishing tool rather than releasing the shear pins 32.

When it is desired to remove the tool or jar of this invention from the well, assuming that it is not stuck in the well itself, the wire line W is raised to thereby raise the entire tool or jar to the surface for the insertion of a new shell or explosive E for another jar when desired.

in PEG. 4, a modification of the invention is shown wherein the lower portion of the jar or tool of this invention is modified. The parts shown in FIG. 4 which are identical with those shown in FIG. 1C bear the same numerals. The anvil A-ll shown in FIG. 4 is modified as compared to the anvil A of FIG. 1C. The anvil A-l has an upper annular shoulder 154 which limits the upward travel of the anvil Al by engagement with the shoulder lie. The anvil A-fl also has a lower annular shoulder 151 which is adapted to engage the upper end of the split retaining nut 52. The travel or stroke of the anvil A4 is longer than that of the anvil A which is accomplished by spacing the shoulder 151 from the upper end of the split nut 52 a greater amount than the distance between the shoulder 51 and the upper end of the split nut 52 in the FlG. 1C modification.

Additionally, the anvil or jarring member A-l has a modified lower end with a cavity 153 and vent holes 53a communicating therewith and with circumferentially spaced longitudinal grooves 151%. Such cavity 153 is adapted to receive an impression member fill (shown in dotted lines) which is formed therein by pouring molten lead into the cavity 153 and the grooves 15317. The vents 153a are not filled with the lead. Such impression member may be formed of impression materials other than lead so long as the material thereof is relatively soft and is capable of bein impressed or deformed by the upper end of a stuck fish or object in a wel In other words, during the use of the anvil or jarring member A-l, the impression member St is in contact with the upper end of the stuck fish or object in the well prior to the explosion within the jar or tool of this invention. When the explosion of the explosive E occurs, the impression member fill is forced downwardly with the jarring action around the upper end of the stuck fish or object in the well to provide a cavity in the member 8i) which conforms with the external shape of the upper end of the stuck fish or object. In that way, an impression is made of the upper end of such stuck fish or object and when the tool or jar of this invention is retrieved to the surface of the well, the operator at the surface will then know what type of fishing operation is necessary and what type of fishing tool should be employed to recover the stuck fish or object.

The operation of the form of the invention shown in FIG. 4 is identical with the form previously described in connection with FEGS. lAlC, except for the obtaining of the impression with the device of FIG. 4 instead of the obtaining of the jar as with the device of FIGS. lA-lC.

Another modified form of the invention is illustrated in FIG. 5 wherein the lower portion of the modified tool is illustrated with the parts which are the same as in FIGS. 1A-1C having the same numerals. The anvil A-Z in FIG. 5 corresponds with the anvil A-ll and the anvil A, except that it is modified for providing a puncturing action when the explosion occurs in the tool or jar. Thus, the anvil or jarring member A-2 includes annular shoulders 25% and 251 which basically correspond with '2 the shoulders and 151 in FIG. 4. The lower end of the anvil or jarring member A-Z is formed with a point 253 so that when the anvil or jarring member A-2 is forced downwardly with the jarring impact as previously explained in connection with FIGS. lA-lC, a puncture can be made in a member such as the bull plug P illustrated in FIG. 5. Such bull plug P is of conventional construction and is merely illustrated by way of example.

During the course of well operations, it often becomes desirable to open the bull plug P to conduct well operations therebelow. Heretofore, there has been no satisfactory way of obtaining the initial puncture in the bull plug. With this device as shown in FIG. 5, the pointed end 253 is forced through the bull plug P with a sufficient jarring force to actually open the plug for subsequent widening if necessary. Additional anvils may be used in subsequent jarring actions which have a greater width to more fully enlarge the opening obtained by the initial puncture with the pointed end 253 so that the bull plug P may be actually opened to substantially the same extent as the internal diameter of the casing to which the plug P is connected. Then, additional well operations may be performed below the plug P by the lowering of well tools through the ruptured bull plug P to the area therebelow.

In the modification of the invention shown in FIGS. 14, the tool is constructed so that well fluids may pass into the body B through the holes 11f, as the body B is lowered into the well bore on the line W.

As noted herein with regard to FIG. 1C, holes or passage means 11 in the lower body portion 11 provide a means to relieve the fluid pressure from the body B so that substantially the full force of the explosive B may be transmitted to the hammer H.

In FIGS. 6 and 7, another modification of the invention is illustrated in which the well fluids are sealed off from entering the lower portion 11' of the body B. The parts shown in FIGS. 6 and 7 which are identical with those shown in FIGS. 1C and 4 bear the same numerals. The anvil A3 shown in FIGS. 6 and 7 is modified as compared to the anvil A of FIG. 4. Also, the lower body portion 11 is modified as compared to the body 11 of FIGS. 1C and 4.

The anvil A3 has an upper annular shoulder which limits the upward travel of the anvil A-S by engagement with the lower annular edge of shoulder 16. The anvil A-3 also has a lower annular shoulder 351 which is adapted to engage the upper end of the split retaining nut 52. The travel or stroke of anvil A-3 is longer than that of the anvil A which is accomplished by spacing the shoulder 351 from the upper end of the split nut 52 a greater amount than the distance between the shoulder 51 and the upper end of the split nut 52 in the FIG. 1C modification.

The anvil A-3 has a cavity 153 in the lower end thereof and vent holes 153a. Circumferentially arranged projections 253a and grooves 2535 are preferably provided in the cavity for more securely holding the impression member 86' in place in the cavity 153, although the cavity 153 may have a smooth bore if desired.

The impression member 3% is shown as being formed of lead wool 8th: and lead fidb covering the lead wool. The impression member 89 may be formed of impression materials other than lead so long as the material thereof is capable of being impressed or deformed by the upper end of a stuck fish or object in a well. The lead 80b is shown as assuming the form of a lead disk 80:: which is placed over the lead wool dda and then molten lead is poured over the disk 890 to form the lead layer 80b which extends into the circumferential grooves 25311. The vents 1530 are open.

The anvil A-3 is used to obtain impressions in the same manner as described with regard to the anvil A-l of FIG. 4. The arrangement and relationship of lead wool 80a and lead 891; enable an accurate and deep impression of the fish in the well bore to be obtained. This in turn indicates to the operator the type of fishing tool which .is best suited to engage the fish and retrieve it from the well here.

The lower end of hammer H is shown in FIG. 6 as resting on the shear disk or plate 20 in a manner as described with regard to FIGS. 1C and 4. The body 11 is provided with a bore 11a, but it is to be noted that the fluid escape passage means 111 shown in FIGS. 10 and 4 has been eliminated from the modification shown in FIG. 6.

Also, the anvil A-3 is provided with a seal ring 352 which engages the inner periphery of lower body portion 11' and prevents well fluids from passing into the bore 114: of the lower body portion 11.

Since the bore 11a is sealed off from the entry of well fluids, then the hammer H works in atmospheric pressure as it moves in the bore 11a toward the anvil A-3.

In order to provide an escape means for the fluid, or gas pressure, existing in bore 11a and in advance of the hammer H as it moves down, the top of anvil A-3 has been cut off, thereby forming a cavity 353 in the body portion 11' which receives the atmospheric gases ahead of hammer H as it moves down. This relieves the gas pressure ahead of hammer H and prevents the excessive build up of pressure which might tend to cushion the blow of the hammer H and enables substantially the full force of the explosive E to be extended in moving anvil A3 longitudinally of the body to contact the fish and obtain an impression thereof.

PEG. 7 illustrates another modification of the invention wherein the force of the explosive E is impinged directly on the top of anvil A3. It will be noted in this form of the invention that the hammer H has been eliminated, and the explosive is similar to the explosive E shown in FIG. 1B and like parts are numbered the same as in FIG.

1B. The wadding 21 preferably rests upon the upper end 356 of the anvil A-3 as illustrated in FIG. 7. The operation of the invention with the FIG. 7 form is the same as previously described with regard to FIGS. 1-6, inclusive, except that the force of the explosion gases act directly on the anvil rather than through the hammer H to move the anvil A4: longitudinally of the well bore. In some circumstances, it may be desirable to use the form of the invention shown in FIG. 7 instead of that shown in FIGS. 1-6.

It may be desirable when employing the form shown in FIG. 7 to provide additional weights 45 to aid in properly positioning the body B as the device is actuated.

The various types of anvils or jarring members at the lower end of the tool or jar of this invention are merely illustrative of the scope of this invention.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the size, shape, and materials as well as in the details of the illustrated construction, may be made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed is:

1. An explosive jar adapted to deliver a jarring blow in a well comprising,

(a) a body having a chamber therein,

(b) an explosive disposed in said chamber,

(c) a force transmitting member operably connected with said body and longitudinally movable relative thereto when said explosive is fired,

(d) a jarring member adapted to be hit by said force transmitting member with a jarring force for imparting a jarring movement to said jarring member to thereby apply a jarring force to any object contacted by said jarring member,

(e) means for mounting said jarring member for longitudinal movement relative to said body and so that the jarring member projects below the lower end of said body before and after detonation of the explosive, and

(f) coacting means on the body and the jarring member to prevent the jarring member from being expelled from the body.

2. An explosive jar adapted to deliver a jarring blow in a well comprising,

(a) a body having a chamber therein,

(b) an explosive disposed in said chamber,

(c) means for detonating said explosive,

(d) a force transmitting member operably connected with said body and longitudinally movable relative thereto when said explosive is fired,

(e) a jarring member adapted to be hit by said force transmitting member with a jarring force for imparting a jarring movement to said jarring member to thereby apply a jarring force to any object contacted by said jarring member, and

(f) means for mounting said jarring member for longitudinal movement relative to said body and so that the jarring member projects below the lower end of said body before and after detonation of the explosive,

(g) means on said jarring member and said body to limit upward travel of said jarring member relative to said body to maintain the jarring member projecting below the body at all times after a jarring blow has been struck, and

(h) coacting means on the body and the jarring membeer to prevent the jarring member from being expelled from the body.

3. An explosive jar adapted to deliver a jarring blow in a well comprising,

(a) a tubular body,

(b) a longitudinally movable hammer in said body,

(c) an explosive disposed in said tubular body above said hammer for moving said hammer longitudinally in said body,

(d) an anvil positioned in said body for longitudinal movement relative thereto,

(e) the upper end of said anvil being spaced from the lower end of said hammer a greater distance than the travel of said anvil in said body after contact by said hammer,

(f) means for guiding said hammer into contact with said anvil to impart a longitudinal jarring blow thereto which is transmitted to any object contacted by the lower end of said anvil,

(g) means for mounting said anvil in said body so as to dispose the lower end of the anvil below the lower end of the tubular body at all times, both before and after the explosive is detonated, and

(h) coacting means on the body and the jarring member to prevent the jarring member from being expelled from the body.

4. The structure set forth in claim 3 including,

(a) a relatively soft impression material at the lower end of said anv-i-l adapted to engage a stuck object or the like in a well for making an impression in such material of the configuration of the upper part of the stuck object, and

(b) means mounting said material on said anvil for movement therewith whereby the jarring force imparted to the anvil is utilized for making the impression in said material.

5. The structure set forth in claim 3 wherein said anvil has a puncturing head at its lower end for puncturing a bull plug or the like or for enlarging an opening in a bull plug or the like when the jarring blow is transmitted to said anvil from said hammer.

6. An explosive jar adapted to be run in a well with a mechanical jar connected at the upper end thereof comprising, (a) a body having a chamber therein, (b) an explosive in said chamber, (c) means operable by a jarring of the mechanical jar for detonating said explosive,

(d) a force transmitting member operably connected with said body and longitudinally movable relative thereto when said explosive is fired, (e) a jarring member adapted to be hit by said force transmitting member with a jarring force for imparting a jarring movement to said jarring member to thereby apply a jarring force to any object contacted by said jarring member; said jarring member having (1) an upper external lateral shoulder and a lower external lateral shoulder and (2) a portion with longitudinally extending external guide surfaces; said body having (1) an internal upper shoulder adapted to be contacted by said upper external lateral shoulder on said jarring member when said jarring member is in engagement with the object to be jarred, (2) a lower internal shoulder adapted to be engaged by said lower external lateral shoulder on said jarring member, said body having (3) sufiicient weight to prevent any appreciable upward movement thereof so that a downward jar on the object by the jarring member is eifected.

'7. An explosive jar adapted to be run in a well comprising,

(a) a body having a chamber therein,

(b) an explosive disposed in said chamber,

(0) a firing pin adapted to detonate said explosive,

(d) a longitudinally movable firing head movable downwardly to hit said firing pin to effect the detonation of the explosive,

(e) a force transmitting member operably connected with said body and longitudinally movable relative thereto when said explosive is fired,

(t) a jarring member adapted to be hit by said force transmitting member with a jarring force for imparting a jarring movement to said jarring member to thereby apply a jarring force to any object contacted by said jarring member,

(g) a wire line, and

(h) means attaching the upper end of said firing head to the lower end of said wire line to prevent relative movement therebetween for lowering the jar in a well or the like by a lowering of said wire line.

8. An explosive jar comprising, a body having a chamber therein, an explosive disposed in said chamber, means mounted in said body to detonate said explosive, longitudinally movable means mounted to move longitudinally in said body and against which the explosion gases of said explosives react to move same longitudinally of said body, said longitudinally movable means including a cavity in its lower end, lead wool in said cavity, and lead covering said lead wool whereby the jarring force imparted to said longitudinally movable means is utilized to obtain an impression in said lead and lead wool.

9. An explosive jar adapted to be run in a well com- 7 prising,

(a) a body having a chamber therein,

(b) an explosive disposed in said chamber,

(c) a firing pin adapted to detonate said explosive,

(f) a jarring member adapted to be hit by said force transmitting member with a jarring force for imparting a jarring movement to said jarring member to thereby apply a jarring force to any object contacted by said jarring member,

(g) a wire line,

(h) means attaching the upper end of said firing head to the lower end of said wire line to prevent relative movement therebetween for lowering the jar in a Well or the like by a lowering of said wire line,

(i) means for mounting said jarring member for longitudinal movement relative to said body and so that the jarring member projects below the lower end of said body before and after detonation of the explosive, and

(j) means on said jarring member and said body to limit upward travel of said jarring member relative to said body to maintain the jarring member projecting below the body at all times after a jarring blow has been struck.

References Cited by the Examiner UNITED STATES PATENTS 1/40 Kinley 166-63 X 12 2,628,816 2/53 Malian 175-4 X 2,729,292 1/56 Hinson 16663 2,978,028 4/61 Webb 16663 FOREIGN PATENTS 806,102 12/58 Great Britain.

OTHER REFERENCES 10 1946, 3rd edition, page 55?.

CHARLES E. OCONNELL, Primary Examiner.

Claims

1. AN EXPLOSIVE JAR ADAPTED TO DELIVER A JARRING BLOW IN A WELL COMPRISING, (A) A BODY HAVING A CHAMBER THEREIN, (B) AN EXPLOSIVE DISPOSED IN SAID CHAMBER, (C) A FORCE TRANSMITTING MEMBER OPERABLY CONNECTED WITH SAID BODY AND LONGITUDINALLY MOVABLE RELATIVE THERETO WHEN SAID EXPLOSIVE IS FIRED, (D) A JARRING MEMBER ADAPTED TO BE HIT BY SAID FORCE TRANSMITTING MEMBER WITH A JARRING FORCE FOR IMPARTING A JARRING MOVEMENT TO SAID JARRING MEMBER TO THEREBY APPLY A JARRING FORCE TO ANY OBJECT CONTACTED BY SAID JARRING MEMBER, (E) MEANS FOR MOUNTING SAID JARRING MEMBER FOR LONGITUDINAL MOVEMENT RELATIVE TO SAID BODY AND SO THAT THE JARRING MEMBER PROJECTS BELOW THE LOWER END OF SAID BODY BEFORE AND AFTER DETONATION OF THE EXPLOSIVE, AND (F) COATING MEANS ON THE BODY AND THE JARRING MEMBER TO PREVENT THE JARRING MEMBER FROM BEING EXPELLED FROM THE BODY.