US2673070A - Jet-type drilling jar - Google Patents

Description

March 23, 1954 w. s. CRAKE JET-TYPE DRILLING JAR Original Filed Dec. 28, 1948 INVEHTOIZ'.

WILF'RED S. CRAKE Hl5 ATTORNEY Patented Mar. 23, 1954 UNITED STATES TENT OF FlCEi Development.

Company, San Francisco,

Califi,

acorporation of Delaware;

Original. application December 28, 1948, Serial No. 67.708. Divided and this application November 18, 1952, Serial No. 321,136

2 Claims.

This application 1 is a division 1 of my copending application Serial Number 67,708, filed on: the

28th day of December; 2635.853.

1948 now U. S; PatentflNo.

This: invention relates to a well tool and per tains more particularly to a jarring tool which may belowered on a cable through a drill string for applyingajarring forceto said drill string.

In drilling an oil well, it occasionally happens thattthe tubing or drill string becomes jammed in: the well: borehole by cavings of sand, formation debris or rock fragments falling into. the borehole and'wedgingthe drill string and drill bit' attached thereto. The. wedging materials aroundthe bit or drill'string are frequently compacted to such extent that circulation of drilling fiuidcannot be relied upon. to wash them away and release the bit. Accordingly, the bit or drill string can only be freed by applying a severe jarring action tothe stuck member.

A tool commonly used. is a mechanical jar adapted to be attached to the lower end of a drill string and. run into the well, where it is connectedto that portion of the drillstring that islodgedl in the jar permits a reciprocating or limited vertical movement of the upper part of the drill string, said reciprocating movement causing jarring action to. the stuck' portion of the drill string. The-main disadvantage with this type of jar is that the drill string must be withdrawn from thewell, equipped: with the jar, and then reinserted into thewell to be connectedito the stuck section of drill: string in the well.

The primary objectof the present invention is to provide a jarring tool adapted to be lowered on a cablewithin a drill string and positioned in' a stuck section of said drill string for engagement therewith;

Another object of this invention is to provide a cable jarring tool adapted to effect a jarring and strong uplifting action at the point, or close to the point, at which the drill string is stuck or wedged.

A further object of this invention is to provide a cable jarring tool adapted to impart a jetting effect to a well fluid within the drill string to aid or restorecirculation within thewell whereby said fluid may dislodge and wash away any materials that tend to immobilize the drill string.

Another object of this invention is to provide a jarring tool of simple and sturdy construction that is readily insertable into and removable from a drill string without the removal of any portion of said drill string.

well borehole. The mechanical between the outer wall Other objects and advantages of the present.

invention will become apparent from the follow.-

ing description, taken with reference to thedraw ing, wherein:

Figure l is a longitudinalview, partly inlcross tool positioned section, of the present jarring within a rotary drill string.

Figure 2 is another jarring tool of Figure 1; after carried by said tool has been detonated.

Figure 3 is a cross-sectional'view of the present. jarring tool incorporating a gas expansible an.

choring means.

i5, carried at the lower end of the drill string; against the wall or more apertures H5 in outlet means: whereby, a. drilling fluid may be circulated during drilling operations by pumping it down through'the drill string l4; out the: apertures l6 and upwards of' said. drill string and the wall 19. ot the borehole.

The present jar lolmay be run into the well onpreferably containing an; insulated a. cable. ll, electrical conductor 38 for firing an explosive.- It is tobe understood that an ordinary cable or wire line may be used employed to ignite the explosive. In this. embodiment the cable II is. attached to a cable socket 39. and the electrical conductor 38 is run through or alongside a sinker bar 12 and a hammer-and-anvil type mechanical jar that may be interposed between the cable H and the tool l0 toaid in sinking the tool jarring it free from the or collar M. The electrical conductor 38 conlll in the well and in tinues downward through the tool 10 terminating at a chamber 33- adapted to contain a detonating mechanism. The jet-type jar I 0 comprises a cylindrical body member 21, reduced diameter. Carried on or formed with said body me'mber 2| is a or multiple slip bowls- 23 having outer tapered faces. movement on said body 2| is a jar integrally anchoring means which comprises a ring or sleeve 24 to which is attached, in any suitable manner, e. g., welding a plurality of vertically depending slip arms 25 which may be either hinged or made of flexible material whereby they may be spread" view in cross sectiontof the. an explosive charge l9 of: the well borehole. One

the drill bit form fluid;

in the annular space l8;

if mechanical devices are.

surrounding drill stringa portion 22* thereof having a slip bowl Slidably mounted for limited longitudinal waterproof material or container may be employed, said material or outwardly toward the inner wall of said drill string M. The lower ends of the slip arms 25 are provided with gripping elements or slips 2% having toothed or serrated faces that are curved to conform to the inner surface of the drill string M. The slips 25 are mounted in slidable engagement with the slip bowls 23, being normally held in their retracted position, as shown in Figure 1, by a tension spring 21. Pins 28 or other suitable fastening means secure the top of the spring 21 to the body member 2|.

Removably affixed to the bottom of the body member 2|, in any suitable manner, as by screw threads 31, is a thick-walled cylinder 29 having a central chamber 33 formed therein, which,

chamber contains suitable firing mechanism for igniting an explosive charge. A thick-walled housing 30, having an axial bore 3| therethrough. is secured by screw threads 32 to the lower end of cylinder 29. The axial bore 3| of said housing 30 forms a chamber in which a charge of explosive 34 may be carried. Chamber 33 containing an explosive cap or a firing mechanism (not shown) and chamber 3| housing the explosive charge 34 are interconnected by a suitable passageway 35. The lower end of the axial bore 3| may be tapered as at 36, if desired, to concentrate and focus the blast from the charge 34 when said charge is detonated.

Any suitable amount and type of explosive charge 34 may be used depending on the amount of jarring and lifting action desired. Prefer-' a slow-burning type smokeless powder of the type used as a propellent charge for military purposes. It is desirable to use a waterproof type explosive as the borehole of the well is generally filled with fiuid. Alternatively, an explosive charge covered with a carried in a waterproof ably the explosive is container being of an easily destructible and relatively thin material such as, for example, rubber, plastic, parchment, aluminum or other metallic foil, and the like.

When the present jarring jar free a drill string at which the drill string is struck is previously tool is employed to determined by suitable means well known to the" art, such as a magnetic tester. The jarring tool I is then attached to the end of the cable [I and lowered through the drill string M to the level at which the drill pipe is stuck. In this case. the cavings 28 are illustrated as wedging the drill bit |5 in place against the wall of the well Is. Hence, the jarring tool I0 is lowered to a position just above the drill bit l5. In operation, the electrical conductor cable H may be attached to a suitable power source and switch means (not shown) at the surface. With the explosive carrying jarring tool Ill in place as shown in Figure l, the firing mechanism or cap contained in chamber 33 is actuated or fired to igniting the explosive jet charge 34. The gases-generated by the igniting charge 34 discharge downwardly through the axial bore causing the parts of the tool body 2|, 22, 20 and 3D to move vertically upward.

The inertia of the spring-supported slip assembly, comprising ring 24, arms 25 and slips 25.

causes it to stand momentarily substantially still whereby the spring 21 is extended and the slips 26 are caused to move outwardly as the backs of the slips slide over the faces of the rising slip bowls 23. The slips move outwardly until the teeth of the slips 2B engage the inside of l4 with drill bit I5, the point.

the drill string M, as shown in Figure 2. Thus, the upward vertical movement of the tool body 2|, 22, 29 and 3D is arrested and the remainder of the explosive thrust is transferred to the drill string |4 whereby said drill string is subjected to a sharp jarring and uplifting action. Prior to firing the explosive 34, the drill string is preferably subjected to a strong upward pull from the surface so that considerable tension exists in the drill string. The vertically-directed explosive reaction of the jet adds greatly and suddenly to this tension, helping to jar the stuck drill pipe free and causing the cavings 20 to be crushed or jammed into the borehole wall l9.

After the explosive force is spent, the weight of the tool body 2 22, 29 and 30 is normally sufficient to disengage the slips 26 from the inner surface of the drill string M as the drilling jar is allowed to drop slightly. If this fails to disengage the slips 26, a mechanical jar |3 may be actuated by pull or release of the cable I Either action causes the slip bowl 23 to slide down-, wardly from the position shown in Figure 2 to that shown in Figure 1, whereby the slips 26 are disengaged. The spring 21 pulls the ring 24 and attached slip arms 25 and slips 26 into their retracted position (Figure 1) thus allowing the,

jarring tool It to be withdrawn to the surface by the cable An additional advantage of the present jarring tool is that the explosive discharge jettingaction may be utilized to restore circulation in a well borehole. It occasionally happens that circulation of drilling fluid down the pipe string I it, out the apertures l6 of the bit l5 and into the annulus I8, is blocked by cavings 2|] in the annulus l8 above the drill bit. At such times. the pressure capacity of the mud pumps at the surface is usually not sufficient to cause the pumped fluid to wash these cavings 20 away and restore circulation. By using the present jet jarring tool and firing it immediately above the drill bit |5, a very high pressure is created inside the lower end of the drill string M which is suflicient to dislodge the cavings 20 and restore.

a body member 59 having a recessed wall por-' tion 5| adapted to house a plurality of anchoring slips 52. A plurality of lateral piston chambers 53 are formed in said recessed wall portion,

said chambers being in communication with an axial bore 54 in said body member 5|) which also serves as a chamber for housing detonating means or materials.

'Slidingly mounted for lateral movement in; the piston chambers 53 in a substantially fluid-- tight manner are a plurality of pistons 55 that are fixedly secured to theinner surfaces of the anchoring slips 52.

serrated or toothed for gripping the inner surface of the drill string 56 when expanded thereand into the chamber 54 housing the ignition means (not shown) Threadedly secured to the lower end of the;

Afiixed to a sinker bar l2 The slips 52 are curved to conform with the inner surface of a surround-. ing drill string 56. The faces of the slips 52 arebody member 50 is a housing member having an axial bore therethrough. The upper part 58 of the bore is enlarged to form a chamber for containing an explosive charge 59 while the lower portion 60 of said bore is shaped to direct the explosive blast downwardly.

In operation, the present jarring tool is lowered into a drill string 56 to a predetermined depth where the charge 59 is exploded in a manner previously described. A portion of the gases generated during the explosion is forced into the axial bore 54 of the body member 50. The pistons 55, in communication with said axial bore 54, are instantaneously forced outwardly by the gaseous pressure causing the attached slips 52 to contact the inner wall of the drill string 56, thus fixedly anchoring the tool in place during the time period required by the explosive bases to escape through the bore 60. It will thus be seen that upon the firing of the explosive charge the drill string 56 is subiected to a sharp jarring and strong uplifting action in a manner similar to that described with regard to the apparatus of Figures 1 and 2.

I claim as my invention:

1. A jarring tool adapted to be lowered on a cable within a tubular string in a well, said tool comprising an elongated body member, a chamber in said body containing an explosive charge, means in communication with said chamber for exploding said charge, a downwardly extending passageway from said chamber to guide the explcsive gases escaping therefrom, whereby an upward reaction thrust is developed to move said body member upwards, and anchoring means outwardly carried by said body member, radially expansible slips carried by said anchoring means,

a portion of the inner surfaces of said slips being in communication with said chamber and being actuated by a portion of escaping explosive gases to grip the inner walls of said tubular string, thereby imparting to said string a jarring upward thrust.

2. A jarring tool adapted to be lowered on a cable within a tubular string in a well, said tool comprising an elongated body member having an axial bore formed in the lower portion thereof and a plurality of lateral openings between said axial bore and the outside of said body member, a chamber forming part of the axial bore in said body containing an explosive charge, means in communication with said chamber for exploding said charge, a downwardly extending passageway frcm said chamber to guide the explosive gases escaping therefrom, whereby an upward reaction thrust is developed to move said body member upwards, and anchoring means outwardly carried by said body member, said an- 7 choring means comprising a plurality of piston means mounted in a substantially flui'dtight manner for limited lateral movement in said lateral openings, and gripping means ailixed to said piston means and movable therewith, said anchoring means being actuated by a portion of escaping explosive gases to grip the inner walls of said tubular string, whereby said upward thrust is transmitted to said tubular string.

WILFRED S. CRAKE.

References Cited in the file of this patent UNITED STATES PATENTS Number

Images