US1941723A - Straight hole drilling device - Google Patents

Description

Jafl- 2 1934. v E. sTRoUD A STRAIGHT HOLE DRILLING DEVICE Filed April 29, 1931 Patented Jan. 2, 1934 STATES STRAIGHT HOLE Voet E. Stroud,

Application April .29, 1931.

3 Claims.

My invention relates to well drilling tools and relates especially to a drilling device which will tend toward maintaining a straight hole.

In drilling wells by the rotary method the drill bit is often caused to work to the side so as to produce a hole which is not straight. This lateral olsetting of the drill is generally caused by inclined subterranean structure.

It is the principal object of my invention to 19 provide a device which may be operated in a a drilling tool adapted to be secured to the lower end of a string of drill pipe, this drilling tool having cutter means secured to the lower end thereof and slidably supporting a pilot member which may be projected from the outer body of the drilling tool into piloting engagement with the bottom of the hole being bored.

It is a further object of the invention to provide a drilling tool of the above character having an outer body adapted to support outer cutters and an inner body adapted to support inner cutters, there being a keyed engagement between said outer and inner bodies for permitting the inner body to slide downwardly into a position of projection from the lower end of the outer body, but at all times causing the inner body to be positively rotated by the outer body.

A further object of the invention is to provide a drilling tool of the above character adapted to use replaceable cutters.

Further objects and advantages of the invention will be made evident throughout the following part of the specification.

' Referring to the drawing, which is for illustrative purposes only,

Fig. l is a vertically sectioned view showing a preferred embodiment of my invention and illustrating one manner in which it may be employed in the drilling of a well.

Fig. 2 is an enlarged fragmentary sectional 50 view showing the lower end of the outer tubular member and further showing the inner member in raised position relative to the outer tubular member.

Fig. 3 is an enlarged cross section on a plane 55 represented by the line 3 3 of Fig. 1.

DRILLING DEVICE Belllower, Calif.

Serial No. 533,678

(Cl. .Z-61) 4 is an enlarged fragmentary section on a plane represented by the line 4-4 oi Fig. 2.

The preferred form of my invention shown in Fig. l includes an outer tubular body 11 having a threaded pin 12 at its upper end adapted to receive a collar 13 which is in turn screwed onto the lower end 14 or" a string of drill pipe. The tubular body 11 has a main bore 15 extending from an upper end point 16 to a lower end point 17, and being longitudinally splined so as to provide longitudinal grooves 18. The lower ends of the grooves 18 are closed by a threaded ring or sleeve 20 which screws into a threaded counterbore 21, this ring or sleeve 20 being of such length that it has a lower end portion 22 projecving below the lower end 23 of the tubular body 1l. An inner tubular member 24 is slidable within the bore 15 of the body 11, this inner tubular member having ribs 25 formed thereon to it the longitudinal grooves 18 oi" the body l1. The ribs 25 are substantiaily in the center of the member 24 so that the ribs 25 act as a division between the upper end 26 and the lower end 27 of the inner tubular member 24. The upper end 25 projects through packing means 3G situated in a counterbore 31 which leads upwardly from the upper extremity 16 of the main bore 15 and includes a lower ring 32 which closes the upper ends or the longitudinal grooves 18, a body of packing material 33, an upper ring 34, and a ring nut 35 which screws into the internal threads 36 formed in the upper portion of the counterbore 31. The extreme lower end 37 of the member 24 is rounded, as shown in Figs. 1 and 2, and has a transverse slot 38, as shown in Fig. 4, adapted to receive an inner cutter member 40 which is held in place in the slot by means 0f a locking screw 4l which is received in a threaded opening 42 in the end 37 and passes through a hole 43 in the inner cutter 40. A mud circulation passage 44 extends axially through the member 24 from the upper end thereof to a point 45 adjacent the extreme lower end 37, and from the lower end or the passage 44 diagonal passages 46 extend downwardly and outwardly so as to discharge streams of drilling mud in iront oi the blades 47 and 43 comprising the inner cutter 40. i

Lugs 5o project outwardly from the lower end or the tubular body 11 and receive bolts 51 for bolting to the lugs the upper blade extensions 52 of outer cutter blades 53 forming an outer cutter 54. The blades 53 are tied together by a ring 55 which is preferably formed or cast integrally with the blades and. is adapted to fit against the lower end face of the body 11, as shown in Fig. 2. The ring 55 ts around the lower portion 27 of the inner member 24 and has a counterbore 56 in the upper portion thereof to t the downwardly extending end 22 of the threaded ring 20 so that the engagement of the counterbore 56 with the projecting end 22 will centralise the cutter 54. As shown in Fig. 2, the inner cutter 40 is of such width that the blades 47 and 48 thereof overlap the inner edges 60 of the blades 53 of the outer cutter 54, and when the inner member 24 is raised to its highest position relative to the outer member 11, as shown in Fig. 2, the cutters 40 and 54 assume the relative positions shown, and the lower cutting edges 6l and 62 of the inner and outer cutter members lie in a flat plane perpendicular to the axis of the members 11 and 24.

A preferred manner of using the device is as follows: In Fig. 1 the drilling device is shown in the lower portion or" a well bore 65, the lower end 66 of which is slightly offset rightwardly. Under ordinary conditions this rightward offset at the lower end of the hole would continue, thereby producing a hole of such croolredness that placing of the casing would be difficult. With my device, however, it is possible to lift the outer tubular member ll by raising upwardly on the string of drill pipe 14, whereupon the inner member 24 will project downwardly from the outer member l1. By raising the outer member 11 through a distance greater than the length of the lower portion 27 of the member 24, it is possible to lift the inner cutter 40 from the bottom 67, as indicated by dotted lines 68, permitting the cutter then to be centralized on the axis A-A of the portion of the hole 65 above the offset lower end 66. Then, by lowering the drill pipe 14 and the parts attached thereto, the cutter 40 may be caused to advance vertically downwardly from the position in which it is shown by dotted lines 68 into engagement with the ilat bottom 67 of the hole 65 and to then penetrate the bottom in the manner shown so as to form a pilot or counterbore 69, which counterbore 69 will of course be eccentric with respect to the lower offset end 66 but will be axially aligned with the straight upper portion of the hole 65. The continued downward movement of the drill pipe 14 will cause the outer body ll and the outer cutter 54 to advance downwardly, and during such downward advance the inner member 24 will guide the outer body axially so that the outer cutter 54 will cut along the dotted lines 7l, concentric with the axis A-A. When the outer cutter 54 reaches and overlaps the inner cutter 40, they will progress downwardly together in overlapped position such as shown in Fig. 2. In the use of my new drilling device the drilling operation is conducted by steps. For instance, fifteen feet of hole will be drilled with the inner and outer cutters 40 and 54 in overlapped relationship as shown in Fig. 2, and the drill pipe will then be raised so as to allow the inner portion 24 to be extended from the outer body 11 due to hydraulic pressure of drilling mud against the upper end of the inner member 24, and a pilot bore 69 will then be iormed in the manner previously described. After the forming of such pilot bore, another fteen feet or other selected length of hole will be bored, and the device again raised and a pilot bore formed. Therefore, the hole will be continued by repeating this process of boring a short length of hole and then forming a pilot bore.

Although I have herein shown and described my invention in simple and practical form, it is recognized that certain parts or elements thereof are representative of other parts, elements, or mechanisms which may be used in substantially the same manner to accomplish substantially the same results; therefore, it is to be understood that the invention is not to be limited to the details disclosed herein but is to be accorded the full scope of the following claims.

I claim as my invention:

1. A drilling device of the character described, including: an outer tubular member having its upper end adapted to be secured to the lower end of a string of drill pipe, and having a bore with longitudinal grooves in the wall of such bore; an inner member slidable within said bore, said inner member having radially projecting ribs adapted to engage said longitudinal grooves, the lower end oi said inner member being adapted to receive an inner cutter of a character to make pilot engagement with the bottom or" the hole being drilled; a ring itted into the lower end of said cuter tubular member, ring providing a lower end wall for said grooves in said outer tubular member; and means on the lower end of said outer tubular member adapted to receive an outer cutter member.

2. A drilling device of the character described, including: an outer tubular member having its upper en d adapted to be secured to the lower end of a string of drill pipe, and having a bore with longitudinal grooves in the wall oi such bore; an inner member slidable within said bore, said inner member having radially projecting ribs adapted to engage said longitudinal grooves, the lower end o said inner member being adapted to receive an inner cutter of a character to make pilot engagement with the bottom of the hole being drilled; a ring fitted into the lower end of said outer tubular member, said ring providing a lower end wall for said grooves in said outer tubular member; means on the lower end of said outer tubular member adapted to receive an outer cutter member; and an outer cutter member secured to said means on the lower end of said outer tubular member, said outer cutter member having an opening therethrough for the passage of the lower end of said inner member.

3. A drilling device of the character described, including: an outer tubular member having its upper end adapted to be secured to the lower end oi a string of drill pipe, and having a bore with longitudinal grooves in the wall of such bore; an inner member slidable within said bore, said inner member having radially projecting ribs adapted to engage said longitudinal grooves, the lower end of said inner member being adapted to re eive an. inner cutter of a character to make pilot engagement with the bottom of the hole being drilled; a ring fitted into the lower end of said outer tubular member, said ring providing a lower end wall for said grooves in said outer tubular' member; means on the lower end of said outer tubular member adapted to receive an outer cutter member; and an outer cutter member secured to said means on the lower end of said outer tubular member, said outer cutter member having an opening therethrough for the passage of the lower end of said inner member, the lower cutting edges of said outer cutter member and said inner cutter lying substantially in a radial plane when said inner cutter is held in fully raised position by said inner member.

VOET E. STROUD.

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