US2243998A - Drill bit for boring wells - Google Patents

Description

Jmm 3, 1941. L w. BLAU 2,243,998

DRILL BIT FOR BORING WELLS Filed March 19,. 1938 14 FIG 6 Q INVENTOR.

Patented June 3, 1941 DRILL BIT FOR BORING WELLS Ludwig W. Blau, Houston, Tex., assignor to Standard Oil Development Company, a corporation of Delaware Application March 19, 1938, Serial No. 196,856

1 Claim.

The present invention is directed to a bit for drilling in so-called soft formations.

The principal object of the present invention is the provision ofv a bit of the character described which will have slicing action as distinguished from a scraping action, and which has a cutting edge of such configuration that the earth through which it passes exerts a sharpening effect upon it.

Another object of, the present invention is the provision of a bit' of the character described having blades of such configuration that the cutting proceeds from the center of the hole outwardly and rearwardly and an outward thrust is imparted to the cuttings.

Other objects and advantages of the present invention will appear from the accompanying drawing in which Figure 1 is a front elevation of a bit according to the present invention;

Fig. 2 is a side elevation thereof;

Fig. 3 is a bottom view of Figure 1;

Fig, 4 is a view, partly in cross section, taken along the line A-A of Fig. 2;

Fig. 5 is a view, partly in cross section, taken along the line B-B of Fig. 2;

Fig. 6 is a view, partly in cross section, taken along the line C-C of Fig. 2; and

Fig. '7 is a view, partly in cross section, taken along the line D-D of Fig. 2.

Referring to the drawing in detail, the bit is provided with a shank I which is illustrated as a sleeve having internal threads 2 to receive the end of a drill stem. It is to be understood that the shank, instead of being an internally threaded sleeve, can be an externally threaded cylinder.

Extending forwardly of the shank is the blade which may be cast or formed integrally with the shank or may be welded thereto in the known manner. The blade, as shown, is bifurcated with each half 4 of the blade separately attached to the shank. For convenience in describing the bit the shankis considered to be joined by the blade halves along plane 3, but, as stated above, in practice the blademay be formed integrally with the shank.

Each half 4, of the blade has a fiat face 5, these faces being placed in juxtaposed position so that in the front view they are divided by the space 6. The upperend or base of each face is a line formed by the intersection of face 5 with plane 3 and gives each face 5 a fiat base. In addition, each face has a pair of curved sides 8 and 8 convexed in the same direction and converging to a point ID. The two faces are arranged with their convex sides all converging to the same point so that in a side view thextwo faces have the appearance of a pair of tongs.

The cutting edge ll of each half 4 of theblade begins at the point In and extends outwardly from the center, upwardly from point Ill and clockwise with respect to the bottom face of the bit in the path of a spiral. That is to say, each cutting edge is convex with respect to the formation to be drilled as shown in Fig. 2 and is convex with respect to the direction of rotation of the bit as may be seen in Fig. 3. The cutting edges of the two halves of the blade, when viewed from the bottom, form a continuous line having the general appearance of the letter S with the convex portion of each half of the letter facing the direction of rotation of the blade. The point at which the cutting edge terminates is removed clrcumferentially from a point on the circular base of the bit intersected by a line tangent to the cutting edge at the'point ID by about 30. The circumferential distance between these points may be greater or less between the limits of about 10 and The front face l3 of each half of the blade, that is the side of the blade which faces in the direction of rotation, is concave with respect to the direction of rotation. In actual configuration it is an arcuate parallelogram having as its short sides the convex edge II and a fiat edge, and as its long sides the curved edges [5 and 8 with edge I5 convex in the same direction as edge 8. Viewed from the front, face 13 approximates a rectangle, since from this angle edge 8 is and edge I5 approximates a straight line and only edge II is curved. Face l3, therefore, is in the form of a scoop with its lower edge convexed in the direction of rotation of the bit as shown by line I2 in Figure 3.

The remaining face I6 of each half of the blade is a segment of a cylinder or other curved surface having its lower end warped inwardly. Surface I6 is bounded by the curved line 15, the curved line 9, the curved line H and the curved line forming the boundary between the upper cylindrical end of surface I6 and plane 3. The boundary between faces l3 and i6, namely line I5, is not necessarily as distinct as pictured. .In practice, these faces will often actually merge and line [5 will be a rounded surface. A distinct boundary is shown, however, in order to facilitate description.

Extending through each half of the blade is a passage I! having its outlet on the face l3 01' each hair of the blade, at a point which is preferably within three inches or the edge II, and having its inlet at the bottom 0! the sleeve l, or in case the shank is a solid member, at the top or solid member so that the passage is in fluid communication with the interior of the drill stem to which the shank is attached. Each water-course is so directed that it discharges water adjacent the leading end 01. the cutting edge of its half of the blade.

as. a forward thrust on the formation being drilled, giving in eii'ect a slicing action and at the same time forcing the cuttings toward the of the hole. This results in the cuttings being squeezed between the bit and the wall of the 'hole, whereby the wall of the hole is plastered.

The nature and objects of the present invention having been thus described and illustrated,

Various changes in design may be made in the above described bit without departing from the present invention which contemplates a bit having a cutting edge which begins substantially at the center of the bit and extends outwardly V and upwardly when viewed from the sides andpreferably outwardly and rearwardly in a curved path when viewed from the bottom and has a scoop-like leading face which is curved rearwardly from the convex portion 01' the cutting edge and then forwardly to the shank of the bit. As can be seen, the leading end of the cutting edge of each half of the bit is at the center 01' the bit and as the bit rotates progressive sections of the cutting edge exert a radial as well what is claimed as new and useful and is desired to be secured by Letters Patent is:

A fish tail bit for rotary drilling comprising a shank adapted to be connected to a drill stem, a pair of spaced blade sections extending forwardly of said shank, each blade section being separate from the other section throughout its to the direction of rotation,

nunwro w. BLAU.

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