US2236761A - Well fishing tool - Google Patents

Description

April l, 1941.

J. E. NICHOLS WELL FISHING TOOL Filed Sept. 27, 1938 l INVENTOR Patented Apryl, 1941 UNITEDSTATES PATENT OFFICE WELL FISHING TOOL Joe E. Nichols, Coalinga, Calif.

Application September 27, 1938, Serial No. 231,925

6 Claims.

This invention relates to a shing tool for recovering small articles, such as drill bit cones. from the bottom of deep wells and particularly refers to a device which is actuated by fluid or hydrauic pressure through the conventional string of drill pipe and is positively controlled from the drilling floor at the surface of the earth.

During the drilling of deep wells, particularly with cone type bits or others having small parts, there may accumulate in the bottom of the hole a number of such parts, usually of very hard substances, which materially hinder drilling operations. This invention comprehends broadly a shing tool which may be run to the bottom of the hole on a conventional string of hollow drill pipe and there be actuated by hydraulic pressure applied by the drilling fluid, compressed air, or gas, to extend downwardly a plurality of spring ngers to surround and grasp the so-called fish and retain it so that it may be withdrawn from the Well. l

A further object of the invention is to provide a simple and inexpensive fishing tool that will automatically indicate to the operator whether or not the sh has been secured.

Another object is to provide a hydraulically actuated fishing tool that will permit drainage of drilling mud or uid from the drill pipe as the latter is withdrawn from the well bore.

vAnother object is to provide a fishing tool that I may be repeatedly actuated at the bottom of the wellso that if the fish is not secured at the rst attempt the device and the drill pipe supporting it will not have to be taken out of the well to be reset.

`These and other objects and advantages will be more fully apparent from the following description and from the accompanying drawingwhich forms a part of this specification and illustrates a preferred embodiment of the invention.

In the drawing,

Figure 1 is a longitudinal sectional view of a fishing tool constructedaccording to this invention, with the operating parts in their retracted position.

Figure 2 is a longitudinal sectional view of the same device shown in Figure 1, with the parts in extended position ready to surround and pick up the sh.

Referring to the drawing, and particularly to Figure l, reference numeral I0 designates the generally cylindrical body of the device, which is usuallly reduced in diameter at II and is threaded at I2 to receive a correspondingly threaded tool joint of a conventional string of drill pipe, by means of which the device is inserted into and withdrawn from the well bore. The bore I3 of body I0 is preferably smoothly nished and extends from an upper shoulder I4 to a lower threaded section I5, the latter adapted to receive a similarly threadedguide bushing I6 which may retain thev operating parts in the body. Near the upper end of bore I3 are one or more fluid ports- II which are normally closed olf by a tubular valve I8 when the device is being run into the well bore in its retracted position.

Valve I8 rests upon or is secured to a piston generally designated I9, and which is composed of an upper plate 20, a resilient packing 2l, and a lower plate 22, the plates being secured together as by bolts 23. Upper plate 2|) is preferably recessed as at 24 and is provided with a central downwardly extending wash pipe or tube 25, the latter extending through piston I9 and .being provided at its upper end with a seat 28 for a valve member such as a ball 21, the purpose of which will be described below.

Extending downwardly from piston I9, and in this case from lower plate 22, are a plurality of circumferentially spaced resilient or spring ngers 28, shaped substantially as shown and, in their retracted position illustrated in Figure 1, being compressed together and retained at their lower ends by the bore 29 of bushing I6. In order to retain valve I8, piston I9, and spring fingers 28 in their retracted position, there is provided an elastic means such as springs 30 and 3|, guided by members 32, 33 and 3l, all of which move freely within bore I3 of body I Il. These springs are preferably of such size that they will exert a considerable force to urge the piston I9 and the lingers 28 upwardly, to displace outwardly through ports I1 any mud or drilling fluid that may be above the piston, and to securelyhold any sh that may be grasped by that portion of spring lingers below bushing I8.

The lower end of body I0 is preferably notched or serrated as at 35, so that it may be used to Y e drill through minor obstructions or so-caled bridges in the well bore, and also to agitate cuttings that may have settled around the Ilsh so that such cuttings may be removed and Washed upwardly by uid passing through the wash pipe 25. Also, it is desirable that bushing I 6 be spaced somewhat above the bottom of body I8 to form a chamberv into which the sh may enter during such cleaning operations and into which said fish may be drawn while the device is being removed from the well bore.

In operation, the body III, in the condition shown in Figure 1, is attached to the lower end of a conventional string of drill pipe, to which is connected the usual mud fluid pumps, rotating and hoisting means and other apparatus used for rotary drilling. and the tool is lowered to the bottom of the well bore. Bridges or other obstructions are cleaned out by rotating the tool and circulating mud fluid, gas, or water downwardly through the drill pipe and through wash pipe 25. Springs 30 and II serve to keep the piston I8, valve I8 and fingers 28 in their upper or retracted position during such operations. After cavings or cuttings have been washed or blown away from around the fish to be recovered, the tool is lifted a few feet oi! bottom. and ball valve 21 is dropped into the drill pipe, passing downward through the mud fluid until it rests on seat 26 of piston I8. The tool is then lowered nearly to bottom, the distance above the bottom being about the distance to which spring fingers 2l may be extended as shown in Figure 2. The pressure on the drilling mud, or whatever fluid pressure is being used to actuate the tool, is increased, driving piston I8 downwardly against the springs 30 and 3|, and extending spring fingers 28 downwardly to surround the fish sme mnd win be released through ports l1 as soon as valve I8 moves downward from the position shown in Figure 1, and the area of these ports should be so proportioned to the duid flow that adequate pressure drop therethrough will be provided to compress springs 3 0 and 3l to the desired point.

The tool is then lowered a slight amount to bend inwardly the lower ends of ngers 28, after which the pressure on the actuating fluid is released. This will permit the springs 30 and 2| to expand, raising the piston. I8, valve I8 and spring fingers 28, the latter being squeezed together by the bore 28 of lower bushing I6 to constrict the fingers about the fish. If the operation is not successful, valve I8 will be raised by piston I8 and springs 30 and 3| to its original position to cover ports I1, and this will be indicated to the operator by failure of the liquid level in the drill pipe to fall when the latter is raised. The operations just outlined, namely, increasing the pressure to extend fingers 28, followed by a release of pressure to retract the latter, may be repeated until the ish is secured, without removing the entire tool and string of drill pipe from the well bore.

If the sh is caught by the lower ends of fingers 28, it will prevent the latter from being drawn through bore 28 of bushing |6so that piston I8 and valve I8 will be unable to move to their uppermost position. Ports I1 will thus be left open to drain the drill pipe, as successive lengths are removed from the well. If the fish is quite small, valve I8 may almost reach its uppermost position, in which case the unequally disposed spaces between prongs 38 at the top of valve I8 will permit drainage through at least one of ports I1.

It is obvious that many alterations and changes could be made in the arrangement show-n without departing from the essential features of the invention, and all such modifications as fall within the scope of the appended claims are embraced thereby.

Iciaim:

1. A well lfishing tool comprising a tubular body adapted to be introduced into a well bore on a drill pipe, a piston in said body, a plurality of circumferentially spaced spring fingers extending downwardly from said piston and adapted to be extended out of said body when fluid pressure is admitted thereto above said piston, a spring urging said piston and said fingers toward their retracted position, a fluid passage through said piston, and means operable from the upper end of said drill pipe for controlling iiuid flow through said passage.

2. A well fishing tool according to claim 1 with the addition of a drain port in said body above said piston and a sleeve extending upwardly from said piston for opening and closing said port.

3. A well fishing tool according to claim l with the addition of guide means in said body cooperating with said spring fingers, so constructed and arranged that said fingers will expand outwardly as they are extended from said body and will contract inwardly as they are retracted within said body.

4. A weil shing tool according to claim l, in which the upper face of said piston is provided with a valve seat in said fluid passage, and said ow control means constitutes a ball adapted to be passed downwardly through said drill pipe to rest on said valve seat.

5. A wellfishing tool according to claim 1 in which said body extends downwardly below said fingers when the latter are in their retracted position, to form a chamber into which said fingers may draw an object to be withdrawn from said well bore.

, pressure on said piston, cutting means at the lower end of said body spaced from the lower end of vsaid resilient fingers in their retracted position to clear an annular space below the ob- `iect to be grasped by said fingers so that they may encircle the same when they are extended from said body, and guide means in said body spaced abovethe lower end of said fingers to contract the same inwardly as they are re tracted by said piston.

JOE E. NICHOLS.

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