US2097040A - Drill bit - Google Patents

Description

06h26, 1937. y F, L, PNQTO 2,097,040

DRILL BIT Filed March 13, 1936 520mm 3.0M?

Patented Oct. 26, 1937 UNITED STATES ATENT OFFICE 3 Claims.

The invention relates to an improvement in drill bits of the type used in the rotary method of drilling wells.

It is one of the objects of the invention to provide a bit having cutting edges and wall wipers so that the bit will be maintained in an accurately centered position in the hole being drilled, and so that the wall will be maintained at the proper diameter.

Another object of the invention is to provide a drill bit having cutting edges in combination with wiper guide portions so that the cuttings from the bit will be agitated and removed from a point adjacent the cutting edge. g

Another object of the invention is to provide an inclined wiper blade for drill bits so that there will be an agitation in front of the cutter blade to assist in removing the cutters.

Other and further objects of the invention will be readily apparent when the following description is considered in connection with the accompanying drawing wherein:

Fig. l is a side elevation of the drill bit looking at the edge of the cutter blades and illustrating the wiper portions extending from the bit body.

Fig. 2 is a side elevation looking at the edge of the wiper portions and illustrating the positioning of the same with respect to the cutter blades.

Fig. 3 is a bottom plan View looking at the cutter edges and showing the circumferential arrangement of the blades and wiper.

Fig. 4 is a top plan view looking down on the bit.

The bit body is illustrated generally at 2 and is here shown as being formed with a box or socket 3 which is threaded at 4 to receive the pin member of the drill collar or tool joint whereby rotation is imparted to the drill bit. The bit may be constructed with a. pin member instead of the boX member 3 as sho-wn, either form being well known in the art.

The box member 3 extends downwardly into the body and has the passages 6 and I diverging therefrom in order to form the discharge ports 8 and 9 whereby the flushing fluid is discharged closely adjacent the cutting edge of the bit.

The lowei` portion of the body 2 is rounded as at Ii! to form a rather blunt nosed portion from which the cutter blades II and I2 extend on opposite sides thereof. These cutter blades as seen in Fig. 1 are inclined slightly forward at I3 and provided with a sharp edge at I4. The rear portion is rounded 01T at I5 to eliminate any excessive drag. As will be seen in Fig. l the port 8 discharges onto the curved face I3 of the bit and (Cl. Z55-61) tends to curl up any shavings or cuttings of the formation which are being shaved off by the rotation of the bit. The mud or water thus discharged tends to break the chips 01T quite frequently and prevents balling up of the bit or sticking of the chips on the cutting face. It will be obvious that the quicker the chips can be removed from the cutting face the less they will interfere with the advancement of the bit.

As the bit is rotated and the chips are removed from adjacent the cutting area they move upwardly around the blunt nose I of the bit and pass upwardly through the well bore. If the chips are large they will naturally settle by gravity in the flow of water or flushing fluid and it is therefore desirable to cause an agitation closely adjacent the cutting area of the bit so as to break up any of the large chips or cuttings and to assist in carrying the cuttings away from the face of the bit. With this in mind, the wipers or guide portions 20 and 2| have also been formed as extending laterally from the body 2. These guides are best seen in Fig. 1 and are upwardly and outwardly beveled at 22 on their lower edges and inwardly and upwardly beveled at 23 on their upper ends. The outer edges 24 of each of these blades is vertical and of such conguration that it will agitate the body of liquid as it moves upwardly away from the cutting edge of the bit. It will be understood that bits of this type rotate anywhere from 40 to 200 revolutions per minute, and that these wiper blades therefore elect a considerable agitation of the liquid in the well bore.

A particular feature of these blades is the fact that the side portions 24 thereof are constantly wiping the walls of the well and tending to plaster up the face of the formation to prevent caving, particular attention being directed to the rounded portion 26 of the wiper blade which tends to throw the liquid in the well bore sharply against the face of the wall formation which has just been uncovered by the cutting edge I4 of the bit. Attention is also directed to the streamlined curvature 2'I of the rear face of the wiper blade 20 which prevents any suction being applied to the face of the well bore which would tend to break down the cake which is being formed by the front face of the blade.

In Fig. 2 the lower end of the wiper blade 20 is shown as rearwardly curved at 30 to assist in agitation of the liquid adjacent the cutting edge. It seems obvious that there will be a flow of fluid around this curved end 3B as the bit rotates and will increase the eddy currents of the liquid so as to assist in removing the cuttings from the cutting area.

Attention is also directed to the fact that the cutter blades Il and I2 terminate at the elevation 32 which is below the elevation of the inclined shoulders 23 on the wiper blades. Thus the smallest area of the well bore which is open to circulation is that area above the lower edge 22 of the wiper blades 2G and the upper edge 32 of the cutter blades ll and I2. In this area therefore will be the greatest compression of the wall formation so that the formation will be packed to prevent caving. It is well understood that when there is little or no caving that greater progress can be made by the bit.

Broadly the invention contemplates a drill bit which will remove the cuttings from the ormation and agitate the liquid about the cutting head in such a manner that the cuttings will be broken up and driven into the wall of the formation so as to prevent caving and to wipe the walls of the formation smoothly so that there will be little or no obstruction to the circulation of the liquid through the well bore.

What is claimed is:

1. A drill bit comprising a body, a rounded nose on the lower end thereof, cutter blades projecting below said nose and projecting laterally from said body to cut the formation being penetrated, and wiper blades projecting laterally from said body between said cutter blades, upwardly and outwardly inclined lower edges on said wiper blades, and upwardly and inwardly inclined edges on the top of said wiper blades above the top of said cutter blades whereby the flow of fluid and cuttings from said bit will be agitated by said wiper blades.

2. A combination cutter and wiper bit having a body, cutter and wiper blades alternatively arranged on said body and projecting radially therefrom, the leading edge of said wiper blades being rounded to force the cuttings from the cutter blades against the wall of the well bore and to agitate the cuttings to disintegrate them as they leave the cutter blades, the trailing surface of said wiper blades curving gradually from said rounded leading edge to prevent eddies in the fluid adjacent said trailing surface.

3. In a drag bit having cutter blades, a plurality of wiper blades projecting laterally between said cutter blades, the forward faces of said wiper bla-des having rearwardly and outwardly Slo-ping surfaces terminating in a rounded edge whereby the cuttings are thrown from the bit sharply against the wall of the well bore to disintegrate the cuttings so that the flow of flushing fluid will readily carry the cuttings away from the drilling area, the lower edge of said wiper blades being inclined rearwardly.

FELIX L, PIVOTO.

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