US1301541A - Rotary core-cutting drill for wells. - Google Patents

Description

J. L. CAMERON.

ROTARY com CUTTING umu TUR WELLS. APPLICATION FILED JULY 13, |918. l 95%10 Patented Apr. 22, 1919.

JARRETT L. CAMERON,

0F EDGERLY, LOUISIANA, ASSIGNOR 0F ONE-HALF 'IO` EVANGELINE IRON WORKS LTD., 0F VINTON, LOUISIANA, A CORPORATION OF LOUISIANA.

ROTARY CORE-CUTTING DRILL FOR WELLS.

Specification of Letters Patent.

Patented Apr. 22, i919.

Application led July 13, 1918. Serial No. 244,715.

To all whom it may concern:

Be it known that I, J ARRETT L. CAMERON, a citizen of the United States, residing at Edgerly, in the county of Calcasieu and State of Louisiana, have invented certain new and useful Improvements in Rotary Core-Cutting Drills for Wells, of which the following is a specification` reference being had to the accompanying drawings. a

This invention relates to the art of well drilling and particularly to a rotary milling tool for use in this art.

lVith wells being driven by the hydraulic rotary process, 'or later when producing oil, tools or pipe may become lostl in the well and cannot be recovered thereby obstructing the well tube a-ndpractically ruining the value of the Well. In numbers of such instances, a Well may be worked over by drilling a long slanting hole out through the well casing above Such obstructions and making a new hole down to the oil bearing sands, which operation is commonly called side tracking a well. This operation is begun by'inserting, in the Well a side tracking guide which is usually a solid iron casting having a diameter nearly that of the well casing at its lower end and having a long upwardly sloping face, concaved somewhat tothe circle of the well casing. `This guide is inserted in thc` wel] to the depth at which the new hole is tobe begun and the hole made by a form of rotating milling cutter attached to the drill pipe, rotatal'ile, by means of the -connected sections of drill pipe reaching to machinery for this purpose at the top ofthe well. The thin wall of the well casing -cutting more readily .than the solid iron guide, the cutting tool follows down the sloping taper of the guide. away from the axial center of the well. cutting away the wall of the well casing tol the same sloping slant as "the, inserted giiide, which operation when completed allows of the further deepening of the well out through this hole to proceed by the usual method of drilling.

Heretofore, the openings in the casing of the well have been made with .practically solid steel tools having longitudinally extending peripheral teeth, or tools having a cylindrical body `portion provided with peripheral teeth but having their lower endsmpering centrally and having peripheral to cut and grind rlway all of the wall of the well casing for` the full length of cutting but this method yof operation presented difficulties. Thus the square ended tool lirst referred to has a tendency to cut into the guide casting and thus there was dihculty in getting a long sloping hole through the well casing, which is absolutely necessary for further drilling. That form of tool having a tapering lower end, while not open to the objection of cutting into the guide casting, has a tendency to run clear outside of the well casing as soon as the center of the cutting tool has passed the casing, thus not completing the tapering hole for the full length of the guide. This tended to bend the drill pipe, that is the tubular shank to which the drill is attached and often cause the drill pipe tobe broken ott' and the tool lost, and at the best the opening in the well casing was not of such form as would permit the ready voperation of tools for further deepening the well.

The general object of this invention is to provide a milling tool for the purpose before described, which is so constructed that `it will out a relatively long elliptical face y pleted so that this piece or tongue of metal,

so long as it remains joined at its lower end to the well casing, acts in a manner as a guide so that the tool follows down as near the center of the core as possible until this core or tongue cut from the well casing is cut off at the eXtreme lower end of the taper on the guide.

A further object is to provide a tool of this character so constructed that instead of cutting away all of the well casing with which the tool comes in contact, the tool will saw narrow slots down on each side of the core or tongue, thus making the tool operate ymuch more quickly than if the tool was solid and cut. through all of the material forming that portion of the wall acted upon by the tool.

The further Objectis to improve upon the form of the milling tool by providing a milling tool made in separate sections and which will cut out a core of the well casing to be removed.

A further object of my invention is to provide a milling tool made in separate seclso tions, any section of4v which when worn out may be replaced by a duplicate sectlon.

A further object is to provide a milling tool of the above character requiring aminimum quant-ity of high tempered cutting steel to accomplish the results required. A further object is to provide a milling tool which will core out a maximum dimension' of the well casing to be out away and provide a means of retaining this oored'center within the tool and the adjacent section of drill pipe when it is removed from the well.

Other objects will appear in the course of the following description.

My invention is illustrated in the accompanying drawings, wherein:

Figure 1 is a side elevation partly in section of my improved milling tool;

Fig. 2 is a sectional view of a -well and casing, and the milling tool as used;

Fig. 3 is a plan viewof the core retaining ring; and

Fig. 4 is a section on the line 4-4 of Fig. 3.

Referring to these figures, it will be seen that my improved tool comprises an annular or tubular body 10, interiorly screw-threaded at its upper end for direct connection to the drill pipe 19 and interiorly screw-threaded at its lower end'for engagement with the screw-threaded body 11 of the drill head-13.

lThe annular body 10 is recessed rearward of the cutting head for the insertion of the core retaining ring 16, this recess being of such depth as to permit of a free rotative movement of the core retaining ringwithin the body, but preventing more than a very slight longitudinal movement of the core retaining ring when the cutting head is in position.

The cutting head is reduced to form the shank portion 11, this shank portion being exteriorly screw-threaded for engagement with the lower end of the section 10 and the cutting head is provided with a plurality of outer cutting edges 14 at dii'erent angles so disposed as to maintain a continuous cutting engagement with the inner circle of a wel casing as the tool progresses down the sloping taper of an inserted guide A, as shown in Fig. 1.

The greatest exterior diameter of the outside edges of the cutting head 13 is equal to the diameter of the new hole to be cut out through the well casing and larger than'the outside diameter of the annular body 10, as shown in the drawings, to thereby cut away la free clearance for the body of the tool.

The interior diameter of the annular body 10 is slightly less than that of the drill pi e 19 and the cutting head has also a slight y less interior diameter. The cutting head 13, in order that it may cut away the wall wof the well casing, must of necessity be made of high grade cutting steel, and by constructing the tool in lccordance with Fig. 2, it is obvious that only a minimum quantity of such steel is-required.-

The core retaining ring 16 is of the same annular formation, is loosely disposed within the recess in the body of the tool, and is held within this recess by the connected end of the cutting head when it is in position. The inward face of this retaining ring 16 is beveled inward and rearward to a sharp edge, and beveled to a suiiciently smaller diameter as to maintain a frictional grip on the cored center of the well casing. This core retaining ring 16 is further provided with a number of longitudinally extending grooves 17 of alesser angle than the beveled face, these grooves being designed to facilitate `the inward passage of rough edges of the cored center of the well casing. It will be seen that by -providing this loosely rotatable retaining ring 16, the cored center is frictionally gripped by this ring and does not tend to rotate with the tool, whereas the cored center would otherwise tend to blnd and rotate with the tool and be broken o 1 As before stated, this tool is constructed for the purpose of cutting a long sloping hole out through the side of the well casing. With a well casing of 6 inches in diameter this sloping hole is from '12 to l5 feet long to allow for further deepening of the welll out through the hole without bending the drill pipe to such 4an extent that it will be vbroken off. It will thus be seen that it is necessary that the lower end. of the drill shall have teeth projecting beyond the body upon which the'cutting head is mounted so as to gradually cut in to theside of the well casing with the drill at a slight angle. Furthermore, it is necessary, under these circumstances, to cut out a core at an angle to the -vertical center of the well and bring out a concave shaped elongated piece of the well casing as a core. It is for this reason that I provide the solid core retaining ring 16 'beveled to a slightly smaller diameter than the inside of the cutting head, this ring being freely rotatable but held from longitudinal movement within the body. lAs the tool is operated to cut downward through the well casing and at an angle to the axis thereof, the tongue so cut out of the well casing will gradually move upward into the interior of the drill and will be engaged by the'ring 16. The ring will, therefore, be held fromrotation and will jam on and bind on the core, bending this concave core slightly as it is forced down thereon. Inasmuch as the retaining ring 16 is smaller in inside diameter than the inside diameter of the body 10,. and is freely rotatable, it remains stationary while the drill rotates sol and it also functions to hold thel core from any great frictional contact with the inside of the body which mighttend to break the core off. The ring is beveled inwardly and upwardly and held from any longitudinal movement so that it may be forced over and maintain a frictional grip on the cored center, as the hole is being made. While not requiring a great force to slip the concave shaped elongated core forward by the tongue cut out of the well casing upwardly. through this bevel retaining ring, a very much greater force will be required to pull it outward against the sharp upper edgeof the ring.

In summing up it will be observed that I have designed a tool that will bring out as a cored center a maximum dimension of the well casing to be cut away and designed a tool in which a minimum amount of high grade cutting steel will accomplish the -result requiredo lt is further to be observed that until the sliver or tongue cut from the well casing and which forms the core is entirely cut away at its lower end, this' sliver or tongue forms a guide for the drill which prevents the drill from suddenly moving out beyond the well casing and running clear outside of the well casing. This sliver or tongue, therefore, acts' as a guide for the tool and the tool follows as near to the center of the core as possible until it is forced to cut olf the core at the extreme lower end of the taper. This tool when withdrawn, therefore, leaves the well casing with a long, relatively narrow opening in its side wall through which further drilling can proceed without difficulty, and thus during the greater portion of its movement, the drill is cutting merely two slits in the metal of the well casing of approximately a width of Having thus described my invention, what l claim is:

1. A tool of the character described comprising an annular body, .including a cutting head, a freely rotatable non-expansible core retaining ring disposed within the body and held from longitudinal movement relative to the body, the ring having an inwardly and rearwardly beveled face, beveled to a slightly smaller circle than the interior diameter of the cutting head and having longitudinally extending grooves.

.2. A tool of the character described comprising an annular body, a core retaining ring disposed within the body-rotatable relative thereto but held from longitudinal movement relative thereto, and a cylindrical citting head detachably carried by the body and having a plurality of radially extending cutting teeth projecting laterally beyond the body and having cutting edges extending parallel to the body and then downward and inward toward the longitudinal axis of the body, the exterior diameter of the cutting teeth being greater than that of the body, the lower end 'of the body being formed with radially disposed teeth.

3. A tool of the character described comprising a hollow body having its interior diameter increased at one end and screwthreaded for' a portion of its length, there being a shoulder defining the .inner end of this portion of the body, an annular cutting head having cuttin teeth at one end and exteriorly screwreaded for engagement with the interior screw-threads of the body, the ,inner end of the cutter head being spaced from said shoulder when the cutter head is in place, and acore engaging ring disposed between the shoulder and the inner end of the cutter head and having free rotation therein but held from longitudinal movement, thering having an interior diameter slightly less than the interior diameter of the body and being beveled centrally and away from the cutter head.`

4. ln combination/with a well drill pi-pe, a rotary milling tool for side tracking wells comprising an annular body having a cylindrical cutting head larger in diameter than the body, the cutting head being formed with radially projecting teeth extending parallel to the axis of the body, downwardly and centrally extending cutting teeth, and the lower end of the body being formed with. radially disposed cutting teeth.

5. A rotary milling tool for side tracking wells including a body annular throughout its entire extent, the lower end of the body having an enlarged head and formed to provide radial teeth extending parallel to the axis of the body, downwardly and inwardly extending teeth, radial .teeth at the lower end of the body, and a core retaining ring disposed within the body and having free rotation therein -an'd held from longitudinal movement. f

ln testimony whereof l hereunto affix my Asi, ;nature in the presence of two`witnesses.

JARRETT L. CAMERON. `llVitnesses:

ALSER WEHRn, FRED SMITH.

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