US3283834A

US3283834A - Rotary expansible drill bits

Info

Publication number: US3283834A
Application number: US343640A
Authority: US
Inventors: Archer W Kammerer
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-02-10
Filing date: 1964-02-10
Publication date: 1966-11-08
Anticipated expiration: 1983-11-08

Description

Nov- 8, 1966 A, w. KAMMERER 3,283,834

ROTARY EXPANSIBLE DRILL BITS lol I N VE NTOR. Heal/E@ W K @n4/145,95@

2 Sheets-$heet l rra EY Nov. 8, 1966 A. w. KAMMr-:RER 3,283,834

ROTARY EXPANSIBLE DRILL BITS Filed Feb. lO, 1964 2 Sheets-Sheet a United States Patent O 3,283,834 RTARY EXPANSIBLE DRILL BITS Archer W. Kammerer, Fullerton, Calif., assigner of onefifth to Archer W. Kammerer, Jr., Houston, Tex., and one-fifth to .lean K. Lamphere, Fullerton, Calif.

Filed Feb. 10, 1964, Ser. No. 343,640 10 Claims. (Cl. 175-267) The present invention relates to drill bits for use in well bores, and more particularly to rotary drill bits through which iiuid can be ejected into the well bores.

An object of the invention is to provide an improved drill bit, such as an expansible rotary drill bit, adapted to perform a drilling operation in a well bore, which is capable of discharging fluid predominantly laterally -against the wall of the well bore in a relatively simple but highly effective manner, for the purpose of conditioning the wall of the well bore, or for discharging cementitious material into the well bore against its wall, the discharging fluid also having the purpose of iiushing the cuttings produced by the bit from its drilling region in the well bore.

This invention possesses many other advantages, and has other objects which may be more clearly apparent from a consideration of a form in which it may be ernbodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the .general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best delined by the appended claims.

Referring to the drawings:

FIGURE l is a longitudinal section, taken along the line 1 1 in FIG. 3, through a drill bit disposed in -a well casing, with its parts in their initial position for moving the drill Ibit in the well bore;

FIG. 2 is an enlarged side elevational view of the lower portion of the drill bit disclosed in FIG. l, with the main portion of the cutters removed therefrom;

FIG. 3 is a cross-section taken along the line 3-3 on FIG. l;

FIG. 4 is a view similar to FIG. l illustrating the drill bit with its cutters expanded outwardly;

FIG. 5 is a view similar to FIG. 4, but on a reduced scale, illustrating the lateral discharge of iiuid from the well bit apparatus and against the wall of a well bore.

The drill bit A illustrated in the drawings is of the expansible type and is specically designed for cutting or milling away a portion of casing B, or similar conduit string, disposed in a well bore C along a desired length. Following milling away of the desired length of casing, fluid can be discharged from the drill bit predominantly laterally against the wall of the exposed well bore D (FIG. 5) to accomplish several purposes, such as the removal of a mud cake therefrom, the hydraulic enlarging of the diameter of the well bore, the depositing of cementitious material in the well bore, or a combination of these several operations. The apparatus A is secured to the lower end of a string of drill pipe E (see FIG. 5) that extends to the top of the well bore, and by means of which the apparatus is lowered through the casing B to a location therein at which the casing milling operation is to commence, and where other operations are also to be performed without removing the drill bit from the well casing.

The expansible rotary drill bit includes an upper mandrel having an upper pin 11 -threadedly connected to the lower end of the string of drill pipe E. This mandrel includes an upper kelly or drill stem member 12 slidably splined to the main body 13 of the bit which has a lower ice guide portion 13a. The exterior of the lower portion 14 of the kelly is non-circular in shape, being telescopically received in a companion non-circular socket 15 formed in the main bit body 13. Specifically, the kelly exterior and `the socket 1S may be hexagonally shaped to enable the kelly 12 to be moved longitudinally with respect to the body 13, while still being capable of transmitting rotary motion to the body.

The mandrel 10 has a limited range of longitudinal movement within the body, its relative downward movement being determined by engagement of the lower end 16 of the kelly with an inwardly directed body shoulder 17, and its upward movement being limited by engagement of an external shoulder or piston portion 18 of the kelly with a cylinder head 19 secured to the body against longitudinal movement with respect thereto. The upper end of the head has a flange 20 engaging an upwardly facing body shoulder 21, the liange being prevented from moving upwardly of the body by a split snap retainer ring 22 fitting in a body groove 23 and overlying the flange 20. An annular guide 24 is releasably secured to the body 13 by a split snap ring 25 above the retainer rings 22.

The body has a plurality of expansible parts mounted on it. These include cutter supporting members 26 pivotally mounted in body slots 27 on binge pins 28 suitably secured to the body to prevent their loss therefrom. Each cutter supporting member 26 depends from the hinge pin 28 and carries a drag or milling cutter structure 29 at its lower end, which may be suitably welded, or otherwise attached, to the supporting member 26.

The cutter supporting members 26 and the cutter structures 29 tend to occupy a retracted position substantially entirely within the confines of the main body 13 of the bit. These cutter supporting members and the cutter structures are expandible outwardly to sever the casing B and mill it away by operating upon the upper end F of the casing therebelow. To accomplish the expansion, each cutter supporting member has an inclined expander surface 30 on its inner portion below the hinge pin 28 4that tapers in a downward and inward direction. Each expander surface terminates in a lock surface 31 formed on a lock portion 32 of t-he cutter supporting member 26. The outward expansion is accomplished by producing relative longitudinal movement between the mandrel v10 and the bit body 13, which will produce relative longitudinal movement between the cutter supporting members 26 and the tubular member 33 of the mandrel 10.

The tubular member 33 includes a lower portion 34 slidably mounted within a guide bushing 35 slidable in a bridge 36 secured to the body and extending; across the body slots 27. This guide bushing 35 -is disposed below the lock portions 32 of the cutter supporting members 26. The tubular member 33 extends downwardly of the guide bushing 35 and is adapted to discharge liluid axially, of the drill bit apparatus toward and against diverter or deector surfaces formed in the body at the lower portion of each of the body slots 27, each of these deector surfaces being inclined from the body axis in a downward and outward direction. Each deliector surface 100 commences at an upper position substantially coaxial of the bit body 13 and the mandrel 10, and inclnes in a downward and outward direction at a substantial angle, which, for example, may be about 45 degrees to the axis ofthe apparatus. The fluid discharging from the mandrel 10 will strike all of the lower deiiector surfaces 100 and will be directed predominantly laterally through the lower ends 101 of the slots or openings toward the wall of the well casing B or wall of the well bore D. Preferably, `the deliector surfaces 100 are disposed below the lower ends of the cutters 29 so that the deflected or diverted fluid is not obstructed in being caused to impinge upon the Wall of thewell bore.

Located initially substantially above the guide bushing 35 and below the hinge pins 28, and in cutter member recesses 37, is a mandrel lock and expander 38 which has outer surfaces 39 adapted to engage the expander surfaces 30 and lock surfaces 31. The lock and expander 38 may be formed integrally with the tubular member 33, the upper end of the latter being piloted within a socket 40 -formed on the lower portion 14 of the kelly 12. An enlarged boss 41 on the tubular member 33 engages a downwardly -lacing shoulder 42 of the kelly, the tubular member being held against this shoulder by a suitable split retainer or lock ring 43 snapped into an internal groove 44 encompassing the kelly socket and engaging the lower end of the tubular member boss 41.

Drilling mud or other fluid can pass down through the central passage 45 in the kelly or drill stem 12 and into the central passage 46 that extends completely through the tubular member 33, this fluid or flue-nt material passing through a nozzle 1015 of suitable size secured within the lower end of the tubular member passage 46, and thence directly downwardly, strik-ing the dellector surfaces 100 and then passing laterally outwardly through the lower portions 101 of the body slots 27 in a direction pred'o-minnantly aga-inst the wall of the well casing B or well bore D. In fact, the fluid might strike such wall substanttially normal thereto. Leakage of fluid `around the exterior of the tubular member 33 is prevented by a suitable side seal ring 47 mounted in the kelly and engaging the exteri-or of the boss 41.

Assuming .the body 13 of the tool to be elevated relatively along the tubular mandrel 10, the inclined expander surface-s 30 of the cutter supporting members 26 will be shifted upwardly along the lock and expander portion 3S of the tubular member 33. During such upward shifting, the cutter supporting members 26 and the cutter structure-s 29 carried thereby will be pivoted about the hinge pins 28 and urged i-n an outward direction. The upward movement of the body 13 with respect to the tubular mandrel can continue until the cutter structures 29 have been shifted outwardly to their fullest extent, as determined by engagement of stop shoulders 49` on the cutter supporting members 26 with companion shoulders 50 tor-med in the body on opposite sides of the body slots 27. When such engagement occurs, the lower end 16 off the kelly portion 12 of the tubular mandrel will engage the body shoulder 17, and the lock and expander 38 on the tubular member 33 will be disposed behind and in engagement with the lock portions 32 on the cutter supporting members 26 (FIGS. 4 and 5). At the same time, it will be noted that the elevation of the body 13 has brought the deflector surfaces 100 at the lower portions of the body slots 27 closer to the nozzle or discharge outlet 105 of the tubular mandrel portion 33, such that any lluid discharging trom the latter will still possess substantial and high velocity when striking the adjacent incl-ined deector surfaces 100.

Relative longitudinal movement between the tubular mandrel and the body 13 of .the tool is accomplished hydraulically in the specic form of apparatus disclosed in the drawings. The piston or enlarged portion 18 of .the drill stern 12 is received within .a counterbore 51 in the upper portion of the body of the tool. This upper portion actually constitutes a cylinder 52 having a cylinder wall `53 extending trom a lower shoulder 54 defining the bottom ol the counterbore 51 to the cylinder head 19.

A conned cylinder space 55 is formed between the pistion portion 18 of the kelly, fthe periphery of the kelly above the piston, and the cylinder 52. A suitable packing or side seal ring 56 may be mounted on the piston por- 'tion 118, which is adapted to slidably seal against the cylindrical wall 53 of the cylinder `52. Fluid is thereby prevented rom passing in a downward direction between the piston and cylinder. Similarly, lluid is prevented from passing in an upward direct-ion out of the annular cylinder space 55- by an inner side seal ring 58 carried by the cylinder head 19 and slidably `and sealingly engaging the periphery or the kelly 12 above the piston 1.8, and also by an outer side seal ring 60 on the head 19 sealingly engaging lthe cylinder wall 53.

Fluid under pressure in the string of drill pipe E and in the tubular mandrel passage 45 can be fed into the cylinder space 55 through one or more side ports 62 establishing communication between the central pas-sage 45 through the kelly 12 and .the cylinder space. Such lluid under pressure is developed, in the form of invention disclosed inthe drawings, by virtue of the fact that the area through the lower nozzle 105 is substantially less than the area of the passage 45 through the kelly portion of the mandrel, or because of the fact that the passage 46 through the tubular member 33 of the mandrel is of a restricted diameter as compared to the passage 45. As a result, the pumping ot drilling mud, or other fluid, at an adequate rate through the .apparatus results in the building up of a back pressure of fluid in the passage 45, wh-ich pressure will then be imposed on the lluid in the cylinder space 55, such fluid under pressure acting upon the cylinder head 19 .to urge the body 13 of the tool in an upward direction with respect .to the tubular mandrel 10 and secure outward expansion of the cutter supporting members 26 and cutter structures 29 to their fullest extent, as above described. During such upward movement of the body 13 along the mandrel 10, the dellector suraces at the lower ends of the slots 27 are, as has been described above, brought closer to the 4discharge end of the nozzle 105 or tubular member 33.

IIn the use of the rotary drill bit A, it is run in the well casing with the cutter supporting members 26 and the cutter structures 29 in their initial retracted positions, such as disclosed in FIG. l. When the drill bit has been lowered to the desired point in the well casing `at which the latter is :to be severed, the pump-s (not shown) at the top of the well bore are started to pump liuid at a sucient rate through the dril'l pipe and into the

mandrel passages

45, 46, and through its lower nozzle 105, building up a back pressure in the kelly passage 45, ports 62 and cylinder space 55, which pressure acts upon the cylinder head 19 to urge the body 13, the cutter supporting members `26 and the cutter structures 29 in an upward direction with respect to .the mandrel 10. During such upward movement, the expander surfaces 30 are brought to bear against the lock and expander portion 38 of the mandrel, the cutter structures being urged in an outward direction against the wall of the well casing. The drill pipe E land the drill bit A are rotated at the proper speed while fluid is being pumped through the apparatus, the outer edges or the cutters 29, acting upon the wall of the casing and gradually milling it away. During this operation, the drill bit is retained in substantially the sam-e longitudinal posit-ion in the well casing. As the casing is cut away, the hydraulic torce acting upon the body 13 raises it and the cutter slipporting members 26 .and cutter structures 29 to a further extent until the outer edges of the cutters have completely severed the casing. Thereafter, rotation of the drill pipe E and the drill bit continues, so that the outer reaming portions of the cutters 29 continue to cut away the casing and dig into the formation until the cutters have been fully expanded outwardly to their maximum extent as determined by engagement of the stop shoulders 49, 50 and the lower end 16 of the kelly portion 12 of ythe mandrel with the body shoulders 17. Wirth the parts in this position, the lock port-ion 32 of each cutter supporting member 26 will bear against the lock and expander portion 38 of the tubular member 33 to preclude inadvertent partial retraction of the cutter structures 29 from the-ir fully expanded position (FIG. 4).

Downweight in the proper amount is now imposed on the string of drill pipe, this downweght being transmitted through the kelly 12 to the body shoulder 17 and from the body 13 to the stop shoulders 50, 49 directly to the cutter supporting members 26 and the cutter structures 29, urging the latter against the upwardly facing severed end F of the well casing. The imposition of the proper downweight or drilling weight on the apparatus and its rotation at the proper speed will cause the cutters 29 to effect a cutting action upon the severed end F of the casing and mill the latter away in a downward direction. During such milling action, drilling fluid is being pumped down through the drill pipe E and mandrel 10, discharging from the lower nozzle 105 against the deflector surfaces 100, which causes the fluid to be directed predominantly laterally toward the wall of the well casing B, the fluid then proceeding upwardly to pass around the cutters 29 and clean them of cuttings, and to carry the cuttings upwardly around the drill bit A and the drill pipe E to the top of the hole (FIG. 4).

After the desired length of casing has been milled away, which, for example, may be of a length of about 20 feet to 40 feet, the downweight imposed on the apparatus A is discontinued. A subsequent operation can now be performed in the well bore without removing the apparatus from the latter. If it is desired to` enlarge the diameter of the well bore D produced by the expanded cutters, circulating fluid is pumped down through the drill pipe E and through the apparatus A, discharging from the lower nozzle S against the deflector surfaces 100 at the lower end of the body slots, the fluid then being caused to move laterally at a substantial angle, which may be approximately 90 degrees, against the wall of the exposed well bore D. The drill string and apparatus connected thereto are rotated at the desired speed during such pumping operation so that the diverted or deflected fluid streams are caused to cover the entire circumference of the well bore D. While the rotation and pumping of fluid operations are continued, the drill pipe E and the drill bit A are gradually elevated, beginning from the lower end of the exposed well bore D, so that the fluid deflected by the inclined lower slot walls 100` is caused to impinge upon the desired length of the wall of the well bore above the lower shoulder F, G provided by the lower end of the severed well casing and the enlarged well bore itself. The apparatus A can be elevated along the entire length of the well bore D, if desired, during its rotation to insure the full coverage of the deflected fluid streams of the entire surface of the exposed well bore. The apparatus can be raised and lowered as often as required to insure the accomplishment of the hole enlarging operation.

A hydraulic hole enlarging operation can occur in the manner described above. Such enlarging operation usually results in the removal of the mud cake from the wall of the well bore D, so that cementitious material subsequently deposited in the well bore along its exposed wall will adhere 'firmly to the latter.

Fluid of the required type and at the proper velocity can be pumped through the apparatus A, while the latter is being rotated and elevated along the well bore, merely to condition the well bore D and remove the mud cake from the wall of the latter without substantially enlarging the well bore, if desired, assurance being had that the diverted streams of fluid will impinge upon the exposed well bore in a highly effective manner, the mud cake, and other undesirable elements, in the well bore being flushed upwardly around the drill pipe E to the top of the hole C.

The apparatus A is usable for depositing cement in the well bore along its exposed portion D, to form a cement plug therewithin, without removing it from the hole after the section of casing has been disintegrated. The pumping of cement slurry downwardly through the drill pipe E and through the mandrel 10 will result in the cement slurry, or other cementitious material, discharging from the nozzle 105 at a high velocity, striking the defiector surfaces 100 at the lower ends of the slots 27 and being directed predominantly against the wall of the exposed well bore. The drill pipe and drill bit can be rotated and gradually elevated while the cement slurry is being discharged from the apparatus A, the point of discharge commencing at the lower end G of the exposed bore and the apparatus `elevated while its rotation continues to insure the direct impinging of the cement slurry against the wall of the well bore and its intimate contact therewith. The cement slurry discharges directly against the wall without interference from the cutters 29, since the deilector or diverter surfaces causes the slurry to discharge through the slots 27 below the lower ends of the cutters. The cement slurry will Slough downwardly and form a plug in the enlarged well bore D.

When the desired quantity of cement slurry has been ejected into the exposed well bore D and to the desired height, the apparatus can be elevated above the upper end of the cement. Flushing fluid is pumped downwardly through the drill pipe E to wash the excess cement from the drill pipe and the drill bit A, such cement slurry being carried upwardly around the rotary drill bit and the drill pipe to the top of the well bore C.

The pumping of fluids through the drill pipe and apparatus can now cease, which will discontinue the hydraulic force holding the body 13 of the tool elevated along the mandrel 10 and the cutters 29 in their outwardly expanded position. The body of the tool .will then drop downwardly along the mandrel back to the position illustrated in FIG. l, allowing the cutters 29 to move inwardly to their fully retracted position, whereupon the drill string E and apparatus A can be elevated through the well casing B above the exposed well bore D and removed entirely from the latter at the top of the hole C.

It is, accordingly, apparent that the apparatus A is capable of performing several operations in the well bore with a single round trip, The apparatus is useful in first performing a milling action to expose the well bore D along a desired length, and without removing the apparatus from the well bore. The exposed portion of the latter can be enlarged hydraulically, the mud cake removed therefrom, or cement slurry discharged from the apparatus into the well bore, or any combination of these operations can be performed. The fluid emanating from the nozzle strikes the defleetor surfaces 100 at the lower end of' the slots to insure adirect and intimate contact of the fluent mass against the wall of the well bore, this action resulting from the simple expedient of providing the inclined deilector surfaces on the body 13 of the drill bit at the lower portion of the body slots. Preferably, the deflector surfaces are angled to such an extent that the fluid deflected therefrom strikes the wall of the well bore at substantially 90 degrees thereto, although the fluid streams can strike the wall of the well bore D in a downward and outward direction, but primarily directly against the wall of the well bore.

I claim:

1. In rotary drill bit apparatus to be lowered in a bore hole on a tubular drill string: a body having an opening through its exterior, said body at the lower portion of said opening having a deflector surface inclined downwardly and laterally outwardly; expandible cutter means on said body; the lower end of said cutter means being located substantially above said deilector surface to provide a substantial unobstructed longitudinal space through the lower portion of said opening between said lower end of said cutter means and said deilector surface; a mandrel movable longitudinally in said body and having a passage adapted to receive fluid from the drill string, the lower end of said passage terminating above said deilector surface, whereby fluid discharged from said lower end strikes said dellector surface and is deflected thereby laterally outwardly through said unobstructed longitudinal space of said opening against the wall of the bore hole; said dellector surface being angled to a degree causing the fluid discharged thereagainst to 7 strike the wall of the bore hole `at substantially 90 degrees thereto without directly striking said cutter means; and coengageable means on said mandrel and cutter means for expanding said cutter means in response to relative longitudinal movement between said body and mandrel.

2. In rotary drill bit apparatus to be lowered in a bore hole on a tubular drill string: a body having an opening through its exterior, said body at the lower portion of said opening having a deilector surface inclined downwardly and laterally outwardly; expandible cutter means on Said body; the lower end of said cutter means being located substantially above said deector surface to provide a substantial unobstructed longitudinal space through the lower portion of said opening between said lower end of said cutter means and said deflector surface; means for expanding said cutter means laterally outwardly of said body, comprising a mandrel movable longitudinally in said body and having a passage adapted to receive fluid from the drill string, the lower end of said passage terminating above and adjacent to said deector surface, whereby uid discharged from said lower end strikes said detlector surface and is deflected thereby laterally outwardly through said unobstructed longitudinal space of said opening against the wall of the bore hole; said deector surface being angled to a degree causing the uid discharge thereagainst to strike the wall of the bore hole at substantially 90 degrees thereto without directly striking said cutter means.

3. In rotary drill bit apparatus to be lowered in a bore hole on a tubular drill string: a body having an opening through its exterior, said body at the lower portion of said opening having a deflector surface inclined downwardly and laterally outwardly; expandible cutter means on said body; the lower end of said cutter means being located substantially above said deflector surface to provide a substantial unobstructed longitudinal space through the lower portion if said opening between said lower end of said cutter means and said deflector surface; means for expanding said cutter means laterally outwardly of said body; passage means in said body adapted to receive uid from the drill string and having a lower end terminating above and adjacent to said decctor surface, whereby fluid discharged from said lower end strikes said deflector surface and is deected thereby laterally outwardly through said unobstructed longitudinal space of said opening against the wall of the bore hole; said deflector surface being angled to a degree causing the fluid discharged thereagainst to strike the wall of the bore hole at `substantially 9() degrees thereto without directly striking said cutter means.

4. In rotary drill bit apparatus to be lowered in a bore hole on a tubular drill string: a body having an opening through its exterior, said body at the lower portion of said opening having a deilector surface inclined downwardly and laterally outwardly; cutter means on said body; the lower end of said cutter means being located substantially above said deflector surface to provide a substantial unobstructed longitudinal space through the lower portion of said opening between said lower end of said cutter means and said deector surface; passage means in said body adapted to receive fluid from the drill string and having a lower end terminating above and adjacent to `said detlector surface, whereby lluid discharged from said lower end strikes said deflector surface and is deected thereby laterally outwardly through said unobstructed longitudinal space of said opening against the wall of the bore hole; said deflector surface being angled to a degree causing the lluid discharged thereagainst to strike the wall of the bore hole at substantially 90 degrees thereto without directly striking said cutter means.

5. In rotary drill bit apparatus adapted to be lowered in a bore hole on a tubular drill string: a body having a plurality of circumferentially spaced slots, said body at the lower portion of each slot having a deflector surface inclined downwardly and laterally outwardly substantially from the axis of said body; expandible cutter means on said body in said slots; the lower ends of said cutter means being located substantially above said deflector surfaces to provide substantial unobstructed longitudinal spaces through the lower portions of said slots between said lower ends of said cutter means and said deflector surfaces; a mandrel movable longitudinally in said body and having a central passage coaxial of said body adapted to receive fluid from the drill string, the lower end of said passage terminating above the inner portions of said deflector surfaces at the body axis, whereby tiuid discharged from said lower end strikes said deflector surfaces and is deflected outwardly through said unobstructed longitudinal spaces of said slots against the wall of the bore hole; said defiector surfaces being angled to a degree causing the uid discharged thereagainst to strike the wall of the bore hole at substantially 90 degrees thereto without directly striking said cutter means; and coengageable means on said mandrel and cutter means for expanding said cutter means in response to relative longitudinal movement between said body and mandrel.

6. In rotary drill bit apparatus adapted to be lowered in a bore hole on a tubular drill string: a body having a plurality of circumferentially spaced slots, said body at the lower portion of each slot having a detiector surface inclined downwardly and laterally outwardly substantially from the axis of said body; expandible cutter means on said body in said slots; the lower ends of said cutter means being located substantially above said deector surfaces to provide substantial unobstructed longitudinal spaces through the lower portions of said slots between said lower ends of said cutter means and said deflector surfaces; means for expanding said cutter means laterally outwardly of said body, comprising a mandrel movable longitudinally in said body and having a central passage coaxial of said body adapted to receive fluid from the drill string, the lower end of said passage terminating above and adjacent to the inner portions of said deector surfaces at the body axis, whereby fluid discharged from said lower end strikes said deflector surfaces and is deflected outwardly through said unobstructed longitudinal spaces of said slots against the wall of the bore hole; said deflector surfaces being angled to a degree causing the fluid discharged thereagainst to strike the wall of the bore hole at substantially 90 degrees thereto without directly striking said cutter means.

7. In rotary drill bit apparatus adapted to be lowered in a bore hole on a tubular drill string: a body having a plurality of circumferentially spaced slots, said body at the lower portion of each slot having a deilector surface inclined downwardly and laterally outwardly substantially from the axis of said body; expandible cutter means on said body in said slots; the lower ends of said cutter means being located substantially above said deflector surfaces to provide substantial unobstructed longitudinal spaces through the lower portions of said slots between said lower ends of said cutter means and said deflector surfaces; means for expanding said cutter means laterally outwardly of said body; passage means in said body coaxial thereof and adapted to receive fluid from the drill string and having a lower end terminating above and adjacent to the inner portions of said deflector surfaces at the body axis, whereby fluid discharged from said lower end strikes said deflector surfaces and is deflected outwardly through said unobstructed longitudinal spaces of said slots against the wall of the bore hole; said deflector surfaces being angled to a degree causing the fluid discharged thereagainst to strike the wall of the bore hole at substantially degrees thereto without directly striking said cutter means.

8. In rotary drill bit apparatus to be lowered in a bore hole on a tubular drill string: a body having a plurality of circumferentially spaced openings, said body at the lower portion of each opening having a deiiector surface in- Cliued downwardly and laterally outwardly substantially from the axis of said body; cutter means on said body; the lower ends of said cutter means being located substantially above said deilector surfaces to provide substantial unobstructed longitudinal spaces through the lower portions of said openings between said lower ends of said cutter means and said deflector surfaces; passage means in said body coaxial thereof and adapted to receive fluid from the drill string and having a lower end terminating above and adjacent to the inner portions of said deflector surfaces at the body axis, whereby lluid discharged from said lower end strikes said deflector surfaces and is deflected outwardly through said unobstructed longitudinal spaces of said openings against the wall of the bore hole; said detiector surfaces being angled to a degree causing the luid discharged thereagainst to strike the wall of the bore hole at substantially 90 degrees thereto without directly striking said cutter means.

9. In a rotary drill bit adapted to be lowered in a bore hole on a tubular string: a body having a plurality of circumferentially spaced slots; expandible cutter means on said body in said slots; said body at the lower portion of each slot having a deflector surface below the lower end of the cutter in said slot inclined downwardly and laterally outwardly substantially from the axis of said body; the lower ends of said cutter means being located substantially above said deflector surfaces to provide substantial unobstructed longitudinal spaces through the lower portions of said slots between said lower ends of said cutter means and said deflector surfaces; a mandrel movable longitudinally in said body and having a central passage coaxial of said body adapted to receive luid from the drill string, the lower end of said passage terminating above the inner portions of said defiector surfaces at the body axis, whereby uid discharged from said lower end strikes said delector surfaces and is deflected outwardly through said unobstructed longitudinal spaces of said slots and below said cutter means against the wall of the bore hole; said deector surfaces being angled to a degree causing the fluid discharged thereagainst to strike the wall of the bore hole at substantially degrees thereto without directly striking said cutter means; and coengageable means on said mandrel and cutter means for expanding said cutter means in response to relative longitudinal movement between said body and mandrel.

l0. In rotary drill bit apparatus to be lowered in a bore hole on a tubular drill string: a body having a plurality of circumferentially spaced openings; cutter means on said body; said body at the lower portion of each opening and below said cutter means having a deflector surface inclined downwardly and laterally outwardly substantially from the axis of said body; the lower ends of said cutter means being located substantially above said deiiector surfaces to provide substantial unobstructed longitudinal spaces through the lower portions of said openings between said lower ends of lsaid cutter means and said dellector surfaces; passage means in said body adapted to receive fluid from the drill string and having a lower end terminating above and adjacent to the inner portions of said deflector surfaces at the body axis, whereby fluid discharged from said lower end strikes said defiector surfaces and is deliected outwardly through said unobstructed longitudinal spaces of said openings below said cutter means and against the wall of the bore hole; said deilector surfaces being angled to a degree causing the fluid discharged thereagain-st to strike the wall of the bore hole at substantially 90 degrees thereto without directly striking said cutter means.

References Cited by the Examiner UNITED STATES PATENTS 2,545,036 3/1951 Kammerer 175-271 2,754,089 7/1956 Kammerer 175-268 2,758,819 8/ 1956 Kammerer 175-267 3,126,065 3/ 1964 Chadderdon 175-269 CHARLES E. OCONNELL, Primary Examiner.

D. H. BROWN, Assistant Examiner.

Claims

1. IN ROTARY DRILL BIT APPARATUS TO BE LOWERED IN A BORE HOLE ON A TUBULAR DRILL STRING: A BODY HAVING AN OPENING THROUGH ITS EXTERIOR, SAID BODY AT THE LOWER PORTION OF SAID OPENING HAVING A DEFLECTOR SURFACE INCLINED DOWNWARDLY AND LATERALLY OUTWARDLY; EXPANDIBLE CUTTER MEANS ON SAID BODY; THE LOWER END OF SAID CUTTER MEANS BEING LOCATED SUBSTANTIALLY ABOVE SAID DEFLECTOR SURFACE TO PROVIDE A SUBSTANTIAL UNOBSTRUCTED LONGITUDINAL SPACE THROUGH THE LOWER PORTION OF SAID OPENING BETWEEN SAID LOWER END OF SAID CUTTER MEANS AND SAID DEFLECTOR SURFACE; A MANDREL MOVABLE LONGITUDINALLY IN SAID BODY AND HAVING A PASSAGE ADAPTED TO RECEIVE FLUID FROM THE DRILL STRING, THE LOWER END OF SAID PASSAGE TERMINATING ABOVE SAID DEFLECTOR SURFACE, WHEREBY FLUID DISCHARGED FROM SAID LOWER END STRIKES SAID DEFLECTOR SURFACE AND IS DEFLECTED THEREBY LATERALLY OUTWARDLY THROUGH SAID UNOBSTRUCTED LONGITUDINAL SPACE OF SAID OPENING AGAINST THE WALL OF THE BORE HOLE; SAID DEFLECTOR SURFACE BEING ANGLED TO A DEGREE CAUSING THE FLUID DISCHARGED THEREAGAINST TO STRIKE THE WALL OF THE BORE HOLE AT SUBSTANTIALLY 90 DEGREES THERETO WITHOUT DIRECTLY STRIKING SAID CUTTER MEANS; AND COENGAGEABLE MEANS ON SAID MANDREL AND CUTTER MEANS FOR EXPANDING SAID CUTTER MEANS IN RESPONSE TO RELATIVE LONGITUDINAL MOVEMENT BETWEEN SAID BODY AND MANDREL.