US2827264A - Drilling tool - Google Patents

Description

March 18, 1958 H. w. slTToN ET AL 2,327,264

DRILLING TOOL 2 Sheets-Sheet 1 Filed Aug. 4, 1954 INVENTORS ATTORNEY March 18, 1958 H. w. sxTTcN ET AL 2,827,264

DRILLINQ TOOL 2 Sheets-Sheet 2 Filed Aug. 4. 1954 INVENTORS TTOR/VEY United States Patent C DRILLING TOOL Hugh W. Sitton'and Thomas H. Sitton, Corsicana, Tex.

Application August 4, 1954, Serial No. 447,758

4 Claims. (Cl. Z55-Q73) This invention relates to drilling vtools and more particularly to tools adapted for use in the releasing of surface casing set ina Well bore, `or tubing cemented in such a bore, or for similar purposes;

In the drilling of wells and especially in the ldrilling and production of oil and gas wells, surface casing is usually set and cemented in the upper endv of thewell bore, such casing providing anchoring means for surface equipment used in carrying out the drilling and producing operations. Such surface casing is frequently ot relatively large diameter to permit the introduction of drilling equipment whereby the drilling operations may be carried on through the casing, and thecasing usually extends downwardly for several hundred feet from vthe ground level. The casing is usually cemented in place at the top and bottom by a surrounding body of cement which sometimes extends throughout the entire length of the casing.

A well in which the casing has been set in this manner isoften produced by the insertion of'a well tubing of smaller diameter than the casing which may also be cemented in place in the casing at one or morelocations throughout its length. Due to the fact that the bores of such wells are rarely straight, and because-of the relative tiexibility of the production string or weil tubing, the tubing is usually not concentrically disposed relative to the casing and bore, and may contact the inner wall of the casing and bore at various locations throughout its length.

When a well which has been equipped in this manner is abandoned, the surface casing and tubing is usually left in the well, due to the diiculty of releasing them from the cement, which results in great loss of valuable material.

The present invention has for its chief object the provision` of drilling equipment which is adapted to be positioned about the exterior of a pipe set in a well bore, such as a casing or tubing and which may be operated to drill away the surrounding cement to release the-casing or tubing whereby the same may be recovered for reuse.

Another object of the invention is to provide drilling equipment of the impact or percussion type embodying a sleeve-like drill adapted to be positioned about the exterior of a casing or tubing and operable to drill away the surrounding layer of cement to release the casing or tubing therefrom.y

A further object of the invention is the provision of drilling equipment which may be usedin connection with well tubing which has been cemented in a well bore or casing, and which is not concentric with the bore or casing, to drill away the cement and release the tubing without cutting orotherwise damaging the tubing. v

Another'object of the invention is toprovide drilling equipment of the kind referred to embodying-means for frice A still further object of the invention is the provision of drilling equipment constructed for use inthe releasing and recovery of well pipe-such as casing or tubing which has been cemented in a well bore, which equipment is of simple design and rugged construction capable of long withstanding the hard conditions of use andl rough treatment to which such equipment is customarily subjected.'

The above and other important objects andV advantages of the invention may best be understood from the following detailed description, constituting a speciiication of the same when considered in conjunction with the annexed drawings, wherein- Figure 1 is a fragmentary side elevational view illustrating a preferred form 'of the invention and showing the equipment in use in the releasing of well casing from the-bore of a Well;

FigureZ isa cross-sectional view, taken along the line 2 2 of Figure 1, looking in the direction indicated by the arrows;

Figure 3 is a fragmentary, side elevational view partly broken. away andV partly in cross-section, details of construction of' the drill of the inventionV as illustrated in Figure l;

Figure 4 is a fragmentary side elevational view of a somewhat different form of the invention, showing the use of the same in the releasing of a tubing string from a well;

Figure 5 is a cross-sectional View taken along the line 5-5 of Figure 4, looking inthe direction indicated by the arrows; and

Figure 6 is a cross-sectional view taken along the line 6-6 of Figure 5, looking vin the direction Vindicated by the arrows.

Referring now to the drawings in greater detail. the invention is illustrated in Figures 1, 2 and 3 in connection with its use in the releasing of casing from a well whose bore is indicated at O, such casing, designated C, having been set in the bore in the rusual manner with or without cementing. In the present illustration the drilling equipment comprises a drill 10 of the impact or percussion type, which is of generally tubular formation and of a size to fit over the outside of the casing and to pass freely over any couplings or connections therein. The drill 10 has a lower end portion l2 which is cylindrical and which is provided at its lower end with a blade like edge formed with cutters or teeth'. The edge portion may have au inner bevelled surface i6 and the teeth i4 may be outwardly ared if desired, to secure eflicient cutting action and to guide the drill over any couplings or connections in the casing without cutting or otherwise damaging the same.

Above the cylindrical portion 12 the drill may be cut away along one side to form an upper more or less semi.- cylindrical portion 18 which may have a longitudinal groove 2t? along its mid portion. The upper end portion of the drill may be provided with tapered edges, one of which is indicated at 22 in Figure 1 to aid in guiding the drill past any external enlargements'in the casing such as a coupling or connection. When the drill is being withdrawn from ther well the upper edge portion of the cylindricalportion i2 may also be bevelled, as seen at-13 in Figure l, for the same purpose.l

A tubular stem or circulating pipe 24 is positioned. in the groove 2t? and secured to the drill inany suitable man'- ner as by welding, this stern extending above the upper end of the drill and being open at its lower end. A pipe 26, which may be in the form of a exible tube or'hose, is attached to the upper end of the tubular stern 24 wherethev drill` may be raised-and lowered and fluid-may be circulated through the stern.

,In making use of this iorm'of the invention, the drill,

v carry away the cuttings or mud formed.-

. the cement or earth formation surroundingl lthecasing mayV then be gradually drilled away from raround the casing, the drill thus forming an enlarged bore about the casing.

During the drilling operation VtheV bore thus formed may be-kept iilled or partly lled with water'supplied thereto through the pipe 26 and tubular stern 24. if desired water may beV circulated Ydownwardly through Vthe stem 24 to pass upwardly about the drill and casing to -When a suticient length of the Vcasing has been thus released from the well bore'it mayV beI-uncoupled'or cut off and removed from the well by the Vuse Vot" any convenient type of conventionalrequipment,provided for that purpose.

A somewhat different form of the drilling equipment of the invention is illustrated in Figures 4, and 6, which is'adapted for use in releasing a welltubing which is not in a position concentric with the well bore and which may be in contact with the wall of the bore or the interior of a well casing therein at one or more locations. In Figures 4, 5 and 6, the well bore orV casing is indicated at O, within which a well` tubing T is positioned, the tubing being ,out of concentric relation to the bore, whereby the tubing is at certain location closer to or in contact with the interior of the bore or casing. In this form of the equipment the drill 12 is of generally tubular shape and is cutaway along one side, as indicated at 18', throughout its length. The opening 18' Yis of somewhat greater width than the external diameter of-the tubing about which the drillris tobe positioned, and is preferably Vprovided with inwardly bevelled side edges 22 throughout the length of the opening so that theV tubing Y' or any coupling or connection thereon may readily pass through the opening in positioning the drill about the tub- The drill 10 is formed with lower end cutters or teeth 14' similar to the teeth 14 of the drill 10 previously described, and has an inwardly bevelled surface 16' which served as a means for grinding the drill past couplings in the tubing. The drill 10 has a longitudinal groove 20T along its mid portion in which a tubular stem 24 is secured in the same manner as in the previously described form of the invention, to which stem a pipe or hose, not shown, may be connected for raising and lowering the drill in the manner previously described.

In making use of this form of the invention, the enlarged borre about the upper end of the tubing may be started with the drill 10 of the form illustrated in Figures V1, 2 and 3, in the manner previously set forth. .Vi/hen the drill in the bore, the tubing passing through the open- Y ing 18 during such lowering of the drill.

By then rotating the drill 10 about the tubing and elevating and dropping the drill at positions where it will not become wedged between the tubing and the wall of the bore, the cement may be drilled away and the tubing released from locationswhere the tubing is not in vconcentric relation to the well bore.. i v

After the drill 10 has been thus used to clear a `location where the tubing is closeV to or in contact with the wall of the bore, it may be withdrawn and the drill 10' againuse-d to carry out further drilling where the tubing is spaced inwardly from the wall of the bore. In this manner substantial lengths of tubing may be released and recovered from the well,'without danger of cutting through the tubing at locations where the tubing is close Y to or in contact with the wall of the bore.

In other respects the drill 1,0 is operated like the drill 10, water being supplied to Vtherbore through the tubular stem 24 in the samemanner as previously described.

It will thus be seen that the invention constructed and operated as described above'p'rovides `drilling equipment which is economical inconstruction and eicient in operation and by which valuable well casing or tubing, which would otherwise be lost, may be released and recovered for further use.

While the invention has been disclosed herein in connection with certain specific embodiments of the same, it will'beV understood that this is intended by wayof illustration only, and that'numerous changes can be made Y in the structure and arrangement of the drills without departing from the spirit of the invention or the scope of the appended lclaims.

Having thus clearly shown and described the invention, what is claimed as newand desired to secure by Letters Patent is: Y

1. A drilling tool for drilling around a pipe set in a well bore comprising a tubular drill shaped to tit over a pipe in a well bore and to operate against the formation around said pipe, cutters on the lower end of the drill, said drill having an external longitudinal groove terminating above Ythe lower end of the drill and a tubular stem in said groove connected to the drill and whose lower end is open.

2. A drilling tool for drilling around a pipe set in a well boreV comprising a drill of generally tubular formation having a cylindrical lower end portion shaped to tit over a pipe in a'well bore and to operate against .the formation around said pipe and aV portion above said cylindrical portion which is arcuate in cross-section, cutters on the lower end of the drill, said lower end portion having an upper inwardly bevelled edge portion positioned to engage an external enlargement on the pipe to guide the drill past said enlargement, said drill having an eXternal longitudinal groove terminating above the lower end of the drill, and a tubular stern in said groove connected to the drill and whose lower end is open.

3. A drilling tool for drilling around a pipe set in a well bore comprising a drill of generally tubular formation having a cylindrical lower end portion shaped to tit over a pipe in a well bore and to operate against the formation around the pipe and an arcuate portion above said cylindrical portion, the lower end of the drill being outwardly flared, cutters on the lower end of the drill, said lower end portion having an upper inwardly bevelled edge portion positioned to engage an external enlargement on the pipe to guide the drill past said enlargement.

4. A drilling tool for drilling around a pipe set in a well bore comprising an elongated drill of arcuate formation in cross-section shapedfto partially surround a pipe in a well bore and to operate against the formation around the pipe, said drill having an external longitudinal groove yand a tubular stem positioned in said groove and connected to the drill and whose lower end is open.

References Cited in the file of this patent UNITED STATES 'PATENTS 187,670 Poney et ai Feb. 2o, 1377 295,045 Parker Mar. 11, 1884 880,881 Hardsocg Mar. 3, 1908 1,345,299 Welsh June 29, 1920 1,882,906 Renter Oct. 18,1932 2,214,970 Mooney Sept. 19, 1940 v 2,305,200 Sitton Dec. 15, 1942 2,449,841 Claypool et al Sept. 21, 1948

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