US2178553A - Well slotter - Google Patents

Description

Nov. 7, 1939.

' c. P. BowlE WELL SLOTTER- Filed May 17, 1937 7 @awww A TT ORNEYS.

Patented Nov. 7, 1939 UNITED STATES PATENT OFFICE 9 Claims.

The present invention relates to apparatus for increasing the effective producing area of a drilled well.

The principal object of the invention is to provide an apparatus which is capable of being lowered into a drilled well, and which can be operated from the surface, to cut slots in the formation into or through which the well has been drilled. The slots are vertical and extend out radially from the well, and there may be as many such slots cut, one at a time, as is desired. Each slot greatly increases the exposed area of the formation, from which the fluid may exude. Some wells which, when drilled in the ordinary way as cylindrical holes, produce comparatively r little fluid because of certain adverse conditions of underground structure or pressure, can be greatly improved by increasing their effective area and thereby securing greater production. By cutting a plurality of narrow slots in the fornation, instead of reamng it out into an enlarged cylindrical chamber, the exposed area is greatly increased, without the danger of destructive caving.

A second object of the invention is to provide an apparatus for the purpose described above which is simple and rugged in construction and easy to operate, and which requires only one source of power or power transmitting connection to provide both its cutting and feeding movements. Other objects and advantages of the invention will be apparent from the following description, which should be read with the un\ derstanding that changes, within the scope of the claims hereto appended, may be made in the form, construction and arrangement of the several parts herein shown and described.

A preferred embodiment of the invention is illustrated in the accompanying drawing, in

which Fig. l is a vertical section showing the device in position in the well.

Fig. 2 is a vertical section taken at right angles to the plane of Fig. 1.

The apparatus requires suitable means for locating or orienting it in the well and holding it securely in position, and suitable driving means for supplying the cutting and feeding power. These holding and driving means may be located either in the well in proximity to the apparatus itself, or at the Surface and connected with the apparatus by strings of tubing. The latter arrangement is shown in the drawing, the reference numeral II indicating a string of tubing to which the apparatus is attached and by which it is lowered or raised and held in position, and I2 indicating a smaller string of either tubing or rods which are rotated to provide the power. The means at the surface for holding the string Il and rotating the string I2 are not shown.

(CI. Z55-1) The drive tubing I2 has a bevel pinion I3 secured to its lower end, which meshes with a gear I4 secured upon a horizontal shaft I5 mounted in the supporting tubing Il. Chains I6 connect said shaft I5 with a second horizontal shaft I1, on which is a sprocket I8. Suitable support must be provided for the bevel pinion I3, such as a spider I9 which provides a journal for the lower' end of the tubing I2.

The diameter of the supporting tubing II is reduced below the shaft I1. Within this reduced portion isa vertically slidable extension 20, which vis prevented from rotating by a guide pin 2l and slot 22. 'I'he lower end of said extension is enlarged, flattened and slotted, as shown at 23, and carries a horizontal spindle 24, upon which an idler sprocket 25 iS mounted in the slot of said end 23. The spindle 24 also serves as a pivot for the forked upper end 26 of an arm 21, said arm extending downwardly and having an idler sprocket 28 mounted in its forked lower end 29.

A flexible endless cutter in the form of a chain 30, having spaced projecting teeth 3|, operates over the sprockets I8, 25 and 28. When thefdrive tubing I2 is rotated in such a manner as to cause the left hand run of the chain to move upwardly, the pull of said chain will swing the arm 21 to the left (Fig. 1). The teeth 3| will, therefore, dig into the left .hand side of the well, cutting a narrow slot in the formation. This continues as long as the drive tubing is rotated, the chain pulling up on the lower sprocket 28 and swinging the arm 21 more and more to the left as the cutting progresses. At the same time, the extension 20, carrying the sprocket 25, moves down to keep the chain tight. A spring 32 may be provided if necessary to assist the weight of the extension 20 to force the sprocket 25 down.

When the device has reached the position shown in broken lines, the slot in the formation will have the shape shown by the dotted line 33. The drive tubing I2 is then raised sufficiently to disengage the bevel gears I3 and I ll, after which the supporting tubing II is pulled up, vthereby straightening out the chain and forcing the arm 21 back to vertical position. The supporting tubing II is then turned to a new position and lowered again, whereupon a new slot can be cut. If necessary, the drive tubing I2 can be rotated in the reverse direction to help straighten out the arm 21. A bearing plate 34 is provided upon the back of the fork 23, to keep the right hand run of the chain from rubbing against the side of the well opposite the slot.

A latch is provided to keep the extension 2|) in elevated position, and thereby to keep the chain straight and the arm 21 vertical, while the machine is being lowered into the well and while it is being turned from one cutting position to another. As an example of such a latch, I have the sprocket I8 rotates clock-wise, the hook 35 is disengaged from the keeper 36, but when said sprocket is reversed, .the finger only is moved without affecting the hook.

As long as the keeper 36 is engaged by the hook 35, the extension 2U Vis held up, and the arm 21 has no tendency to swing away from its vertical position. However, when the sprocket I8 begins to rotate in the cutting direction, the hook is released, thereby allowing the extension 20V to drop down as soon as the arm 21 swings out.

The hook and keeper are provided with inclinedfaces as shown, so that they -automatically engage When the extension 2D is raised by the straightening out of the chain.

The machine is illustrated as operating below the bottom of the well casing, which is shown at 4|. It is entirely possible, however, that with` cutters 3| of the proper material, the slots could `be cut through the casing. Thus the machine can be operated at any point in the depth of the well.

It will be seen that the cutting means, i. e., the chain, 30 is self-feeding. The same power, applied through the rotating tubing I2, not only moves the chain linearly but also, on account of the pivotal mounting of the arm 2l, causes the cutting run of said chain to swing out and feed itself laterally and upwardly into the formation. Thus only one power connection is necessary, outside of that for raising, lowering and holding the entire machine.

It will also be seen that, when the device is in inoperative position the cutter chain forms an elongated loop with substantially vertical parallel side runs, and the three supporting sprockets I8, 25 and 28 are substantially in vertical alignment, thus enabling the machine to be lowered into the well. The cutting movement of the chain, however, pulls said supporting sprockets out of alignment, and causes the side runs of the chain to spread' apart into the form of a triangular loop, one of said side runs being forced against ethe side wall of the well to cut a slot therein.

I claim:

1. A well slotter. comprising a body capable of being lowered into a well, a flexible endless cutter carried by said body, said cutter having two subsaid cutter when inoperative in the form of anV elongated loop with susbtantially vertical side runs, and driving means for moving said cutter, the force exerted by saiddriving means 'causing the side runs of said cutter to spread apart so,

that vat leastc one of said runs will cut into the wall of thc well.

3. A well slotter comprising a body capable of being lowered into a well, a flexible endless cutter, movably connected supporting members therefor Afin-` positioned to hold said cutter when inoperative in the form of an elongated loop with substantially vertical side runs, driving means for moving said cutter, the force exerted by said driving lmeans causing the side runs of said cutter to moving said cutter, the force exerted by said driv-l ing means causing the side runs of said cutter to spread apart so that at least one of said runs will cut into the Wall of the Well, and the movement of said cutter releasing said locking means to permit said supporting members to follow the spreading movement of said cutter, thereby keeping the loop thereof tight.

5. A well slotter comprising a body capable of being lowered into a well, a flexible endless cutter carried by said body, means for moving said cutter, a plurality of supporting means over which said cutter runs, said supporting means being substantially in vertical alignment to maintain the cutter in the form of an elongated loop with susbtantially vertical side runs when inoperative, and said supporting means being movable out of vertical alignment to spread the side runs of said cutter apart to cause at least one of them to cut into the wall of the well.

6. A Well slotter comprising a pair of movably connected body sections, a iiexible endless cutter passing around said sections, said cutter having the form of a vertically elongated loop and said sections being in substantial alignment when in inoperative position, said sections being movable out of alignment to spread the loop of said cutter laterally to cause it to cut into a wall of the well, and means for moving said cutter.

7. A well slotter comprising a body capable of being lowered into a Well, a ilexible endless cutter carried by said body, said cutter being in the form of a loop with two substantially vertical runs, means for moving said cutter, and means for changing the shape of said loop to spread said runs apart and cause one of them to cut a slot in the wall of the well.

8.`A well slotter comprising a body capable of being lowered'into a well, a iiexible endless cutter carried by said body, means for moving said cutter, a plurality of supporting means over which said cutter runs in the form of a loop, and means for changing the relative positions of said supporting means to change the shape of the loop of said cutter.

9. A well slotter comprising a body capable of being lowered into a well, a vertically movable member carried by said body, a second member pivotally connected with the first member for horizontal swinging movement, a iiexible endless cutter, guiding means for said cutter rcarried by said body and said second member, said cutter causing said second member to swing horizontally When said first member is moved vertically, and

means for moving said cutter.

CLIFFORD P. BOVVIE.

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