US1961390A - Well bit - Google Patents

Description

June 5; 1934. J. B. RAGSDALE WELL BIT Filed Feb. 7, 1933 r m M v .M.

John B. Ragzsda/e Patented June 5, 1934 UNITED STATES PATENT OFFICE WELLBII V Ragadale, Whittier, 01111., aaaignor to John B.

Globe Oil Tools 60., Los Nletoa, notation of california Calif acor- Application February 'z, 1933; Serial .No. 655,546 3 Claims. (01. 255-61) This invention relates to a well tool and relates more particularly to a well bit for use in the rotary method of well drilling. A general object of the invention is to provide a simple, practical well drilling bit including a readily detachable and replaceable cutter head having improved cutting parts and a novel and effective means for handling the circulation fluid.

Another object of the invention is to provide a cutter head for a well bit having simple dependable cutting parts formed and related so that they-are particularly rapid and effective in their penetration of the earth formation and insure the drilling of a straight hole or well bore.

Another object of the invention is to provide a well bit including a shank, a cutter head having a detachable flange and bolt connection with the shank, and an improved means for handling the circulation fluid so that the cutting parts of the cutter head are effectively flushed.

Another object of the invention is to provide a well drilling bit of the character mentioned including a plurality of outlets or passages for the discharge of circulation fluid that are positioned and related to the cutting parts of the detachable bit head so that the cutting parts are kept clean and free of cuttings to greatly increase the cutting speed of the tool.

Another object of the invention is to provide a well bit of the character mentioned in which the fluid circulating passages do not complicate the structure and do not in any way interfere with the connection between the shank and the cutter head.

Another object of the invention is to provide a well drilling bit of the character mentioned in which the cutting parts or teeth are formed and related to one another so that the bit operates smoothly and is rapid in its cutting action.

A further object of the invention is to provide a well drilling bit that is sturdy and dependable in construction and simple and inexpensive of manufacture.

The various objects and features of the invention will be better and fully understood from the following detailed description of a typical form and application of the invention, throughout which description reference is panying drawing, in which:

Fig. 1 is a side elevation of the bit provided by the present invention. Fig. 2 is a bottom elevation of the bit, and Fig. 3 is a view of the lower end of the shank with the cutter head removed. The well drilling bit provided by the invention includes generally, a shank 10, a detachable cutter head 11 on the shank 10, and means 12 for handling the circulation fluid.

The shank 10 is an elongate member adapted to be attached to the lower end of an operating string of drill pipe, or the like. The shank 1! inhad to the accomcludes a main part or stem 13 and'an enlarged lower end part 14. A screw-threaded pin 15 is provided on the upper end of the stem 13 to facilitate the connection of the bit with the operating string. A plurality of spaced annular grooves 16 is provided in the stem 13 adjacent its upper end to provide spaced annular wickers or ribs 17 adapted to be engaged by a fishing tool in the event that the bit is lost in the well bore. The enlarged lower end portion 14 of the shank 10 is provided to carry the cutter head 11 and is yoked or formed with two spaced side parts 18 with an elongate groove-or socket 19 between them. The socket 19 extends vertically upward from the lower end of the shank and extends across the enlarged lower end portion 14 from one side to the other. The lower end portion 14 of the shank is enlarged or widened in the direction of the socket 13 so that its side parts 18 project in opposite directions from the lower end of the stem 13. The lower faces or ends 20 of the side parts 18 are flat to form abuttments for receiving the detachable cutter head 11.

The cutter head 11 is in the nature of a unit that is removably attached to the lower end of the shank 10. The cutter head 11 is preferably a single integral unit or part as illustrated throughout the drawing. In accordance with the invention, the cutter head 11 includes a body 21 to engage or seat against the lower end of the shank, a tongue or flange 52 for extending into the socket 19, main or forward cutting parts 22, rear cutting parts 23, inner cutting parts 24 and reaming blades 25. The body 21 of the bit head extends across the lower end of the enlarged portion 14 of the shank and has a flat upper end 25 adapted to seat against the lower end faces 20 of the side parts 18. The flange 52 projects from the upper end of the bit head body 21 and is shaped to fit the socket 19. Enlargements or ribs 28 are provided on the rear side of the flange relative to the direction of rotation of the bit and are received in grooves 29 in the walls of the socket 19. The ribs 28 constitute reinforcements for the reaming blades 25 as will be hereafter described. The ribs 28, in cooperating with the grooves 29, prevent lateral shifting of the flange 52 in the socket 19. The detachable connection between the bit head body 21 and the shank 10 includes bolts 30 extending through spaced transverse openings in the side parts 18 and the flange 52. The heads of the bolts 30 and the nuts 31 threaded on the bolts may be countersunk in the opposite sides of the enlarged lower end 14 of the shank as illustrated in the drawing.

The flange 52 projects from the opposite ends of the socket 19 to provide the reaming blades 25. The blades 25 are adapted to act on the formation at the side walls of the well bore and have comparatively long vertical cutting edges 32. The main or forward cutting parts 22 and the rear cutting parts 23 are in the nature of teeth pro- Jecting downwardly from the lower end of the cutter head 11 to engage the formation at the bottom of the well bore. The forward and rear cutting parts are arranged in two substantially diametrically opposite sets or groups each including a forward cutting part 22 and a rear cutting part 23. The forward cutting parts or teeth 22 project downwardly from the cutter head 11 at points ahead of the reaming blades 32, while 'the rear cutting parts 23 are located behind the reaming blades.

The main or forward cutting parts 22 are comparatively wide or broad extending from beyond the outer ends of the enlarged portion 14 of the shank to points short distances from the vertical axis of the tool. In accordance with the invention, the forward cutting parts 22 are located so that their outer portions extend beyond the forward faces of the cutter head body 21. The forward cutting parts 22 have flat substantially vertical front faces 33 facing-in the direction of rotation of the bit. The outer portions of the forward cutting parts 22 project considerable distances below the cutter head body 21 to provide comparatively long reaming edges 34. In the preferred construction, the forward cutting parts 22 are substantially radial relative to the axis of rotation of the drill as illustrated in Fig. 2 of the drawing. Each forward cutting part 22 is provided with a plurality of stepped cutting edges to engage the formation at the bottom of the well bore. The cutting edges of the forward cutting parts 22 are stepped downwardly and outwardly, that is, each cutting part 22 has a plurality of cutting edges arranged in a downwardly and outwardly stepped series. In accordance with the broader aspects of the invention, the forward cutting parts 22 may be provided with any suitable number of stepped cutting edges. In the particular tool illustrated in the drawing, there are three lower cutting edges 22 22 and 22 provided on each forward cutting part 22. It will be apparent that the forward cutting parts 22 provided with the stepped cutting edges operate to make a series of annular cuts in the formation at the bottom of the well bore, the cuts joining one another to constitute a single comparatively wide annular out. As the innermost cutting edges 22 of the forward cutting parts 22 are spaced from the center or axis of rotation of the drill, they leave a core that is cut or destroyed by the inner cutting parts 24. The forward or main cutting parts 22 may be braced or reinforced by ribs 35 extending downwardly from the lower end of the cutter head body 21.

The rear cutting parts 23 project downwardly from the lower end of the cutter head body 21 and supplement or'aid the outermost cutting edges 22 of the forward cutting parts 22. The rear cutting parts 23 are in the nature of downwardly projecting blades having lower cutting edges 55 which follow the outermost cutting edges 22 of the forward cutting parts 22 in their action on the formation at the bottom of the well bore. The forward faces of the rear cutting parts 23 are preferably fiat and vertical, and substantially radial relative to the central axis of the drill. In the particular cutter head illustrated in the drawing, there is a single rear cutter 23 provided in each set or group of cutting parts and the rear cutting parts 23 of the two groups are substantially diametrically opposite.

The rear cutting parts 23 may be braced or reinforced by ribs 36.

The inner cutting parts 24 are provided to destroy or cut away the core left by the forward cutting parts 22. The inner cutting parts 24 are in the nature of blades resembling the fish tail type of cutting blade. The inner cutting parts 24 project downwardly from the lower end of the cutter head body 21 and extend radially outward in opposite directions from the vertical center of the drill. In accordance with the invention, the inner cutting parts 24 are disposed transversely of the two sets or groups of forward and rear cutting parts. The transverse inner cutting parts 24 may be sufficiently wide to overlap the innermost cutting edges 22= of the forward cutting parts in their action on the formation. The inner cutting parts 24, in being substantially transverse of the other cutting parts of the tool, insure the smooth steady operation of the bit.

The means 12 for flushing the cutting parts of the cutting head provides for the downward discharge of the circulation fluid at points immediately in front of each forward cutting part 22 and between the forward and rear cutting parts. The means 12 for handling the circulation fluid includes a central longitudinal fluid passage 40 in the shank 10. The passage 40 extends downwardly from the upper end of the threaded pin 15 to a point adjacent the enlargement 14 of the shank where it discharges into an enlarged chamber 41. A fluid passage 42 is provided in each side part 18 of the shank enlargement and extends downwardly from the bottom of the chamber 41 to the lower outer sides or corners of the shank enlargements 18.

Nozzles or flow beans 43 are provided on the discharge ends of the passages 42. The flow beans 43 may fit into enlargements or counter bores in the lower ends of the passages 42 and project downwardly from the body 21 of the cutter head at points immediately in front of the forward cutting parts 22. The flow beans 43 may be welded or otherwise attached to the body 21 of the cutter head and project from the lower end of the bit head to bring the discharging circulation fluid to points adjacent the bottom of the well bore immediately forward of the forward cutting parts 22. The fluid passages 42 are of comparatively large diameter and the openings or passages 44 in the flow beans 43 are of less diameter than the passages 42 to increase the velocity of the discharging fluid. The provision of the nozzles or flow beans discharge of the circulation at a high velocity below the lower end of the cutter head and concentrates the wear or abrasive action of the solid matter in the circulation fluid at the flow beans. The flow beans 43 may be comparatively inexpensive and may be easily replaced when worn. The circulation fluid under pressure discharging from the flow beans 43 effectively flushes the forward faces of the cutting parts 22 to prevent the 'accumulation of cuttings or solid matter, and insures an effective circulation at the bottom of the well bore.

It is a feature of the invention that the fluid handling means 12 provides for the discharge of circulation fluid from the cutter head 11 at points between the forward cutting parts 22 and the rear cutting parts 23. Passages 46 are provided in the side parts 18 of the shank and extend downwardly from the chamber 41 to the lower ends 20 of the parts 18. Nozzles or flow beans 47 43 provides for the $1 are arranged in counter bores or enlargements in the lower ends of the passages 46 and project downwardly and outwardly from the faces 20. Openings 48 of elongated cross section are provided in the body 21 of the cutter head to receive or pass the flow beans 47. The flow beans 47 may project from the lower end of the cutter head body 21 as illustrated throughout the drawing. The flow beans 47 discharge from the lower end of the cutter head at points between the forward cutting parts 22 and the rear cutting parts 23. In practice, where the rear cutting parts 23 are comparatively short and the flow beans 47 are directed outwardly as well as downwardly, the flow beans 4'7 may be positioned inwardly of the rear cutting parts 23 as clearly illustrated in Fig. 2 of the drawing. The nozzles or flow beans 4'7, in being positioned behind the forward cutting parts 22, discharge the circulation fluid at points where it is effective in preventing the accumulation of solid matter or cuttings on the lower head of the cutting part 21. The fluid passages 46 may be comparatively large in diameter and the openings 49 in the flow beans 4'7 are of less diameter than the fluid passages 46 to increase the velocity of the fluid under pressure as it discharges from the drill. The reduced openings in the flow beans 4'7 concentrate the scouring or abrasive action of the solid matter in the circulation fluid at the flow beans.

It is believed that the operation of the well drill provided by the present invention will be readily apparent from the foregoing detailed description. It is to be noted that the shank 10 and the cutter head 11 are of simple, sturdy construction and that the cutter head 11 may be easily and quickly attached and detached from the shank. The cutting parts are arranged and related to provide for a smooth and rapid cutting action or penetration of the earth formation. The forward cutting parts 22 provided with the stepped cutting edges 22*, 22 and 22 make an annular cut in the earth formation having a stepped lower wall and are thus effective in drilling a straight hole or bore. The rear cutting parts 23 follow the outermost cutting edges 22 of the forward cutting parts in their action on the formation at the bottom of the well bore and aid in stabilizing the drill during operation. The inner cutting parts 24 remove the core left by the forward cutting parts 22 and in being disposed transversely of the cutter head, provide for the smooth steady operation of the drill. The means 12 include the fluid passage discharging immediately in front of each forward cutting part 22, and the fluid passages discharging between the cutting parts greatly increase the cutting speed of the drill as it keeps the cutting parts free of accumulations of cuttings. The four fluid discharge nozzles or flow beans effectively distribute the circulation fluid to flush the cutter head and provide for the proper circulation at the bottom of the well bore. The provision of the four fluid discharge passages does not complicate or render the construction expensive as the two forward discharge passages 42 are entirely within the shank, and do not necessitate the provision of openings or passages the cutter head. It is to be noted that the fluid handling passages do not intersect or in any way interfere with either the socket 19 or the openings passing the bolts 30.

Having described only a typical form and application of my invention, I do not wish to limit myself to the specific details set forth, but wish to reserve to myself any changes or variations that may appear to those skilled in the art or fall within the scope of the following claims:

Having described my invention, I claim:

1. A well bit including a shank, a detachable cutter head on the shank, a flange and socket connection between the head and shank, and sets of downwardly projecting cutting parts on the head each set including, a forward tooth and a rear tooth spaced behind the forward tooth relative to the direction of rotation of the bit, there being a fluid duct extending downwardly into the shank from its upper end, there being a plurality of fluid passages in the shank communicating with this duct and discharging downwardly immediately in front of the forward teeth, an aperture in the lower end of the head between the teeth of each set, fluid passages in the shank communicating with said duct and discharging downwardly through said apertures, the fluid passages being spaced from the socket and flange of said connection, and flow beans at the discharge ends of the passages projecting through the apertures and having reduced openings passing the fluid.

2. A well bit including a shank having a lower end face, a detachable cutter head on the shank having a part engaging said face and having ports therein, two sets of cutting parts on the head each set including, a forwardtooth, and a rear tooth spaced behind theforward tooth relative to the direction of rotation of the bit, there being fluid passages in the shank extending to said face to direct fluid to the front of the forward teeth, and discharge nozzles carried in the lower ends of the said passages and projecting from the shank downwardly through the parts in the head to points beyond the lower end of the head.

3. A cutter head for a well bit including a shank having an enlarged lower end portion having a diametrically disposed slot extending up- 1 wardly into it from its lower face, a body having a flange projecting upwardly into the slot, bolts extending transversely through the shank and flange to retain the flange in the slot, substantially diametrically opposite outer cutting blades projecting from the lower end of the body, the blades being substantially radially disposed and having a plurality of downwardly and outwardly stepped lower cutting edges, the innermost cutting edges being substantially spaced from the central axis of the body, reaming edges on the outer ends of the blades, rear teeth projecting from the lower end of the body behind the outermost cutting edges of said blade, reaming cutters on the body spaced above rearwardly of the said blades, and a fish tail blade projecting from the lower end of the body and located concentric with the longitudinal axis of the bit with its blades in a plane angularly related to the outer cutting blades, there being fluid passages in the shank extending to its lower end,

' and there being apertures in the body registering with the fluid passages, and flow beans at the discharge ends of the passages projecting through the apertures and disposed to direct fluid to the blades.

JOHN B. RAGSDALE.

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