US2320137A - Rotary drill bit - Google Patents

Description

May 25, 1943. A. w. KAMMERER ROTARY DRILL BIT Filed Aug. 12, 1941 fig. 2.

I N V EN TOR. ARK/ E2 T/l fkllMMb-eee,

BY I

ATTORNEY.

its required diameter.

Patented May 25,

.. norm! mun. m

mm- W.Kammercr,1 ullerton, Calif.

"npplicatlon August 12,

10 Claims.

This invention relates to earth boring tools, and more particularly to drilling bits used in the rotary drilling of oil, gas and similar wells.

The present case is a continuation-in-part of my prior application entitled "Well drilling bits," Serial No. 358,946, filed September 30, 1940.

An object of the present invention is to obtain the discharge of drilling fluid directly upon the bottom of the bore hole being produced by a drill bit of the combined roller and drag cutter type, for the purpose of effectively removing cuttings from the well bore and increasing the rate of penetration of the cutting elements into the formation.

A further object of the invention is to provide a drill bit of the combined roller and drag outter type which is capable of projecting a stream of drillingfluid directly upon the bottom of the bore hole being produced, this stream'also beingefi'ective to maintain the drag cutter and roller cutter elements of the bit free from cuttings.

Yet a further object of the inventoin is to provide a combined roller and drag cutter type of rotary drill bit of stronger and sturdier construction than heretofore available.

This invention possesses many other advantages and has other objects that will become apparent from a consideration of the embodiment shown in the drawing accompanying and forming part of the present specification. This form will now be described in detail to illustrate the general principles of the invention, but it is to be undertsood that such detailed description is not to be taken in a limiting sense, since the inven tion is best defined by the claims appended hereto.

Referring to the drawing:

Figure 1 is an eievational view of a drill bit, parts being removed for purposes of clarity, and other portions being shown in section;

Figure 2 is a generally longitudinal section taken along the line 2"2 of Figure 1; and

Figure 3 is a plan view as seen from the bottom of Figure 1.

As disclosed in the drawing, the drill bit includes amain body or shank i having the usual threaded tapered pin ii at its upper end for attaching the bit to a tubular string of drill pipe (not shown), by means of which the drill bit is rotatable from the surface of the bore hole, in a well-known manner. Depending from the main body i0 is a pair of legs l2, l2 rotatably carrying side or gauge toothed cutters i3, 11 .whose purpose is to remove the outer portions of formation material and maintain the hole to These cutters are each 1941;: Serial No. 408,492

- rotatably mounted on a suitable bearing support il-fl xed to a leg I! and inclined inwardly and downwardly toward the axis of the bit. The cutters l3,. II are preferably of such length as to position the inner ends of their uppermost teeth closely adjacent one another, to permit their cleansing, as described below.

The formation material within the annulus a: cut by the side roller cutters i3 is removed by cutters of the drag or blade type. This drag assembly i5 consists of outer drag cutters i6, its. and inner drag cutters i1, Ila. disposed at an angle to the former and leading them as regards the direction of rotation of the drill bit. The drag assembly is preferably formed of two main parts, each consisting of an outer drag cutter It or its and an inner, leading drag cutter H or l'la connected to the former by a web ill or No.

The outer drag cutters i6, iia are suitably attached to depending legs l9, l9 disposed between the legs l2, I2 supporting the roller cutters it, as by welding material 20. These cutters i6, l6a may extend along their supporting legs l9 for disposition substantially at right angles to the axes of the roller cutters i3. It is to be understood, however that this angle can be varied somewhat, if desired, depending upon the particular portion of each leg l9 to which the outer cutter It or I60. is attached. I

The outer drag cutters It, I to remove an an- .nulus y of formation material from the bottom of the hole within the path a: cut by the roller cutters l3, whereas the inner drag cutters l1, I'Ia remove formation material 2 within the path 1/ traced by the outer cutters. The bottom cutting edges lib ot the outer cutters are preferably disposed above the bottommost cutter teeth l3a or the side roller cutters, while the bottom cutting edges ill) of the inner drag cutters are preferably disposed above that lib of the outer drag outters i8, lid, to enhance the drilling effectiveness of the bit and the production of a vertical hole, as more particularly brought out and claimed in my United StatesrPatent No. 2,244,537, patented June 3, 1941.

It is to be noted that a space 3 remains between the upper inner edges of the outer drag cutters I6, I61: to allow positioning of the uppermost teeth I31) of the side roller cutters i3 ad jacent one another. The inner drag cutters l1, Ila. fastened to the outer cutters I6, I61: by the respective connecting webs l8, l8a, are disposed on opposite sides or a central plane ofthe drill bit, which plane lies generally along the axes of the roller cutters it. These inner drag cutters are substantially parallel to one another, being spaced apart by a small distance 6, resulting in the tendency for a core of material to remain as the drill bit rotates that is of too small a size to sustain itself during operation of the drill bit on the bottom oi the hole. breaks off and cannot impede effective and emcient operation of the drilling tool in the well bore.

Unification of the entire bit construction is completed by welding the outer upper portions" 2| of each inner drag cutter I1, I10. to the stationary bearing support ll of one oi the roller cutters l3, and attaching its inner portion to the opposed stationary bearing through the medium of a transverse arm 22 welded or otherwise se cured to both of these members l4 and I1, Ila. Inasmuch as the stationary bearing supports l4 carying the side cutters l3 and the outer drag cutters l6, Ilia are welded to their respective depending legs l2, IS, the welding of the generally parallel, spaced, inner drag cutters I I, Fla and their arms 22 to the opposed bearing supports i4 integrates and unifies the entire bit construction.

The bearing supports I4 are made functionally integral with one another by the inner drag cutters l1, lla and their arms 22, which, in effect, provide two spaced braces therebetween. Moreover, the outer drag cutters I6, lGa are given material support in addition to that afforded by their attached legs by the integrating of each inner drag cutter I! or Ila and its associated arm 22 to the bearing supports [4. Still further support is given to the outer and inner drag cutters on each side of the bit, since the bearing supports it themselves serve as a means for transmitting loads from one set of drag cutters l6, I! through the other set I611, I111 to the drag cutter leg l9 on the other side of the bit. strong and sturdy combined roller and drag cutter bit construction has been provided, permitting operation without failure under heavy drilling weights and at high rotative speeds.

The side roller cutters l3 and outer drag cutters l6, Ilia are maintained free from detritus by fluid issuing from suitable nozzles 23 communicating with a fluid chamber 24 merging into a fluid passage 25 extending through the bit body l and upper threaded pin ii. A central nozzle 26 is provided in the bit body to receive fluid from the fiuid chamber 24 and discharge it downwardly through the spaces between the outer drag cutters l6, Mia and the space d between the inner drag cutters i'la directly onto the bottom of the bore hole, from where the cuttings are flushed outwardly towards the side of the bit for upward passage therearound and along the exterior of the drilling string to the surface of the well bore. As was stated above, the core of formation material at the bottom of the hole that might tend to form as a result of spacing the inner drag cutters from each other is eliminated automatically during operation of the bit since it is of too small dimension to sustain itself, and therefore, readily disintegrates. This action is assisted by the hydraulic force of the fluid jet issuing from the central nozzle 26 which not only acts directly upon the bottom of the hole to maintain it free from cuttings, but also acts upon the cutting faces of the inner drag cutters l1, l'la to keep them clean and available for efilcient penetra- It is, therefore, apparent that a,

This core readily tion into the hole bottom. The central nozzle 28 can also accomplish a further purpose by directing fluid for action upon the inner portions l3b of the side cutter teeth as they reach their uppermost positions, to clean them of any adherent cuttings and place them in condition for maximum penetration into the formation at the bottom of the bore hole.

It is accordingly apparent that a rotary drill bit has been provided which is not only of sturdier construction than tools of similar types heretofore available, but which also assures the maintenance of the bit and bottom of the hole free from cuttings or other adherent matter with greater facility.

I claim:

1. A drill bit, including a main body, bearing supporting means carried by 'said body. side roller cutters rotatably mounted on said bearing supporting means, a drag assembly secured to said main body and having inner and outer cutters disposed at an angle to each other, said inner cutters lying in separate planes that are spaced from each other, and means for securing said inner cutters to said bearing supporting means. I

2. A drill bit, including a main body having a pair of depending legs, bearing supporting means extending inwardly from said legs, side roller cutters rotatable on said bearing supporting means, a second pair of legs depending from said body between said first-mentioned pair, a drag assembly secured to said second pair of legs and having inner and outer cutters disposed at an angle to each other, said inner cutters being arranged in spaced, generally parallel relation on opposite sides of a central axial plane of the bit; and means for securing said inner cutters to said bearing supporting means. a

3. A drill bit, including a main body, bearing supporting means carried by said body, roller cutters rotatably mounted on said bearing supporting means, spaced drag cutters extending between said main body and bearing supporting means and secured directly to both said main body and said bearing supporting means, and means for projecting fluid through the space between said drag cutter directly onto the bottom of the bore hole being produced by the drill bit.

4. A drill bit, including a main body, bearing supporting means carried by said body, roller cutters rotatably mounted on said bearing supporting means, and spaced drag cutters securing said bearing suporting means together, said drag cutters lying in separate planes that are spaced from each other so as to provide a plurality of spaced braces between said bearing supporting means.

5. A drill bit, including a main body having a pair oi-depending legs, bearing supporting means extending inwardly from said legs, side roller cutters rotatable on said bearing supporting means, and a pair of drag cutters extending between and securing said bearing supporting means together, said drag cutters lying in spaced, generally parallel relation on opposite sides of a central axial plane of the bit so as to provide a pair of spaced braces between said bearing supporting means.

6. A drill bit as defined in claim 4, including nozzle means for directing drilling fluid through the space between said drag cutters directly upon the bottom of a bore hole being produced. 7. A drill bit as defined in claim 5, including centrally located nozzle means for directing drilling fluid through the space between said drag cutters directly upon the bottom of a bore hole being produced.

,8. A drill bit, including a main body having a pair of depending legs, opposed bearing supports extending inwardly and downwardly from said legs, side roller cutters rotatable on said bearing supports with their upper portions adjacent one another, a pair of drag cutters extending between and securing said bearing supports together, said drag cutters lying in spaced, generally parallel relation on opposite sides of a central axial plane of the bit, and nozzle means for directing drilling fluid'onto said adjacent side cutter portions and through the space between said drag cutters directly upon the bottom of a bore hole being produced.

9. A drill bit, including a main body having a pair of depending legs, opposed bearing supports extending inwardly from said legs, a roller cutter rotatably mounted on each bearing support, a second pair of legs depending from said body between said first-mentioned pair, a drag assembly secured to said second pair of legs and having inner and outer cutters disposed at an angle to each other, said inner cutters being arranged in spaced, generally parallel relation on opposite sides of a central axial plane of the bit, means for securing said inner cutters to said bearing supports, and a nozzle for projecting drilling fluid through the space between said inner cutters directly upon the bottom of a bore hole being produced.

10. A drill bit, including a main body having a pair of depending legs, opposed, inclined bearing supports extending inwardly and downwardly from said legs, a roller cutter rotatably mounted on each bearing support, drag cutters secured to said main body and lying generally at right angles to the axes of said roller cutters, said drag cutters being spaced from one another to permit the upper, inner portions of said roller cuttersto lie closely adjacent one another.

ARCHER W. KAMMERER.

Images