US1778252A - Rotary jar - Google Patents

Description

Oct. 14, 1930. FENTRESS 1,778,252

ROTARY JAR Filed Feb. 14, 1928 GEORGE E FENWESS INVE TOR ATTORNEY necessary.

Patented Oct. 14, 1930 PATENT OFFICE GEORGE E. FENTBES S, OF LOS ANGELES, CALIFORNIA ROTARY JAR Application filed February 14, 1928. Serial No. 254,280.

My invention relates to the art of rotary drilling with especial reference to certain improvements in rotary jars.

In oil well drilling and particularly at excessive depths, tools and pipe are liable to become stuck in the hole. A simple straight pull on such objects to the capacity of the hoisting equipment is not always powerful enough to recover them. In such emergencies the operation known as jarring is J arring consists in striking a blow, in either direction, as close to the bound place as is possible, and the purpose of the tool referred to as a jar is to strike such blows. It is an object of my invention 'to provide a jar which produces a steady succession of blows and which is so designed as to be used in rotary drilling.

provide a jar which produces the desiredjarring effect by a simple rotation of the drill pipe while maintaining it under a steady up ward strain. The peculiar advantage of such jarring is that the blow is superimposed on a steady pull, thus greatly increasing its effectiveness. By jarring with a steady upward pull on the pipe any slack due, for instance, to loose connections, is absorbed bythe pull, and the force of the blow is thus transmitted without los's,'direc tly to the part to be jarred free.

.It is a still further object of my invention to provide. a rotary jar including" rugged means for transmitting rotation. Experience has shown that it is good practice to run a jar above the bit when in diflicult drilling. Such use requires the jar adapted to transmit the full drilling torque.

Another object of my invention is to provide a jar which utilizes the elasticity of the drill pipe in the production of blows.

I attain theseobjects by means of the mechanism illustrated in. the accompanying drawing in which:

Figure 1 is a sectional elevation showing the striking elements in contact.

Figure 2 is a sectional elevation showing the striking elements separated and about half set to deliver a blow.

Figure 3 is a section on the line 3-3 of igure 1.

Figure 4 is a section on the line 4.4 of Figure 2.

Figure 5 is F i ure 2.

- y improved jar is connected to the drill pipe by the sub 11 at its upper end, and by the threaded pin 12 at its lower end. The jar thus becomes a part of the drill stem. The body of this jar is composed of two parts, a sleeve l3 and a sub 14, the sub closing the lower end of the sleeve and secured thereto by the threads 15. This body is relatively stationary during jarring, the moving part of the jar being mandrel 16, functioning within the sleeve and joined to the top sub a section on the line 5-5 of 55 I by threads 17. The mandrel extends entire- It is a further object of my invention to.

ly through the body of the jar, the central bore 18 permitting the usual mud circulation. 7 The means for causing the jarring blows comprisesthe thread 19 on the mandrel and the mating thread 20 in the sleeve. These threads are interrupted as indicated in Figure 3. An anvil 21 is provided in the sleeve 7 anda mating hammer 22 is provided on the mandrel. Hammer and anvil are in contact when thethreads are ready to engage. By

' stretched, and as the threads disengage the mandrel is forcibly jerked upward by the elasticity of the pipe, the hammer striking the anvil a goodly blow, depending for its force'on the pipe tension, the weight of the hammer and the speed of rotation.

The means for transmitting rotation through my improved jar comprises the square 23 formed on the mandrel and the socket 24 formed on the sub 14, the socket being adapted to receive said square. When drilling, the mandrel is lowered until these parts engage, thus locking the jar. When again required for use thefree movement of the mandrel inside the sleeve is suflicient to disengage the square 23 from the socket, permitting the mandrel to be rotated without rotating the sleeve.

Mud is excluded from the interior of my improved jar by the stuffing boxes 25 and 26. A suflicient amount of lubricant is maintained inside the jar to materially reduce the wear on the threads.

When using my present invention a bit may be jarred loose' by pulling a suitable stretch in the drill pipeby means of the calf wheel and then rotatingthe drill pipe. The speed.of rotation and the amount of tension are subject to control by the driller. The rotation produces a succession of upward arring blows of great force and as the jar makes headwaythe tension in the pipe is maintained by means of the calf wheel.

4 vInrotary jars heretofore usedit has been necessary to manually operate the jar. The

driller first lowered the drill pipe, rotated it to latch the ars, pulled the desired tension in the drill pipe and finally rotated the pipe backwards to unlatch the jars,'thus allowing the elasticity of the pipe to produce the desired blow. This operation. is obviously laborious and is also destructive to equipment. A distinct danger exists in-rotating the pipe left handed in that a tool joint might unscrew. v

My improved jar is easy on equipment and strikes a ranidsuccesslon of blows. A long travel of the mandrel is neither necessary nor desirable to the production of a hard blow, A large wearing surface is provided to receive the impact, and the threads can be made large enough to wear a considerable time. The economy of such a jar is obvious.

I claim as my invention: 1, A rotary jar comprising: an outersleeve; means at the lower end of said sleeve for connecting the same mandrel longitudinall said sleeve; means at t e upper end'oif said continuous rotation of said mandrel .relative to said sleeve in conjunction with a steady.

upward strain on said drill stem produces a continuous succession of blows of said hammer on said anvil.

2. A rotary jar comprising: an outer sleeve; means at the lower end of said sleeve for connecting the same to a drill stemya mandrel longitudinally disposed through said sleeve; means at the upper end of said mandrel for connecting the same to said drill stem; a hammer on said mandrel within said ward strain on said drill stem. 3. A device as and for the purpose set forth inclaim 2 in which the mandrel is provided with a polygonal section and the sleeve is provided with a socket adapted to receive said polygonal section of the mandrel, when said mandrel -is'lowered in relation to said sleeve, in such manner that rotation ma be transmitted through said jar at the will 0 the operator.

In witness that I claim the foregoing I have hereunto subscribed my name this 9th day of February, 1928.

GEORGE E. FENTRESS.

to a drill stem; al disposed throughmandrel for connecting the same to said drill I stem; a hammer comprising a collar integral with said mandrel and presenting an impacting flat face upwards; an anvil within said sleeve adapted to receive the impact of said hammer. on its entire downward-looking f ce; a plurality of interrupted threads on said mandrel and mating interrupted threads on said sleeve, said threads engaging in such downwardmanner that said hammer moves ly 1n relation to said anvil during the engagement of said threads, said threads being m dependent of said hammer and said anvil, the interruption of said threads being sufficient to permit the mandrel to longitudinalb said sleeve and cause the 1y travel throng hammer tov strike said anvil, said threads,

anvil, and hammer being so arranged that

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