US1238707A - Roller-bit. - Google Patents

Description

H. A. BARDEEN..

ROLLER BIT.

APPLICATION FILED SEPT. I| 1915.

Lfm, PaIenIeaAug. 28,1917.

,- their action is a grinding one,

HUGH A. BARDEEN, 0F LOS ANGELES, CALIFORNIA.

ROLLER-BIT.

Specification of Letters Patent.

Patented Aug., 28, fllt?.

Application filed September 1, 1915. Serial No. 48,549.

To all whom t may concern Be it known that l, HUGH A. BARDEEN, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles and State of California, have invented a new and useful improvement in RollenBits, of which the following is a specification.

My invention relates to the art of drilling oil wells or the like, that system of drilling commonly designated the rotary system, in which a long column or string of drill pipe is rotated by means of a table located at the surface of the ground, the string of drill pipe carrying at its lower end some sort of a cutting tool commonly designated as a bit The first object of the invention is to provide a bit which will rapidly and economically cut away the bottom of the hole especially when working in very hard rock.`

In the rotary system of drilling, a heavy mud is employed, this, mud being forced downwardly through the string of drill pipe and emerging through holes placed at or near the cutting portion of the hit. This mud is used for the purpose of carrying away the cuttings of the bit and also for the purpose of providing hydrostatic pressure and cementing means for retaining the walls of the well.

It is common practice in the drilling art to employ a bit commonly designated as a fish tail bit, this bit consisting of a dat body having a cutting edge at its lower end, such bits having special efficiency in that the fiat body tends to thoroughly mix the mud and to compact it and force it against the wall of the well. The flat body is also very ecient in guidin the cutting edges so that a straight hole will be roduced. The fish tail bits are objectionab e, however, in that and they do not work well in layers of hard rock, commonly termed shells The second object of my invention is to provide a bit which will have a fiat body adapted to guide the cutting members and y to thoroughly mix the mud, and which at the same time will be provided with very eiicient cutting members, enablin it to drill much more rapidly than the iis tail bit. xthere have been produced in the ast, and are new on the market, a considerale number of bits in lwhich rolling cutters are employed. These bits are quite efficient, but are costly to maintain due to the special form of and particularly to cutters employed and due to the fact that expensive oiling devices have to be provided for the purpose of preventing wear on the cutting members.

The third object of my invention is to provide a bit having a rotary cutting member which will be inexpensive to produce and replace and which will not require any special means of lubrication.

It has generally been assumed in the case of rolling cutters, that they should be designed in such a manner that there would be no rubbing action of the cutters on the bottom of the hole. The majority of inventors who have attempted to produce roller bits, have attempted to use conical rollers so that the speed of travel on all parts of the roller would correspond to the movement of the bit at that point on the bottom of the well. lt is my present opinion that this theory is incorrect and that the cutters of the roller bit should be so designed that there is con siderable rubbing action. It is true that this tends to wear the cutters, but it also tends to givethe bit a greater drilling capacity which is highly desirable.

The fourth object of the invention is to provide a bit in which the cutters not only roll on the bottom of the hole, but in which certain parts of the cutters have an abrasive or cutting action tending to greatly increase the eiiiciency of the bit.

I have found that the most economical way to operate a roller bit is to provide a bit which will have relatively inexpensive cutters which cut rapidly, thereby giving a bit of great capacity and which at the same time can be quickly and easily replaced at nominal cost. i

The fifth object of the invention is to provide means for so securing the cutters of a. roller bit that they can be readily removed and replaced.

I have also found that any oiling system is expensive and troublesome, and the sixth object of the invention is to provide a bit which will operate without the necessity for any such special oiling device.

lf have further found that there is a great tendency for fish tail bits, or similar bits, having a Hat body, to wear on their outer edges so that the usefulness of such body 1s greatly reduced after it has been in the well for a short time.

Further objects and advantages will -be evident to one skilled in the art after an im specti'on of the attachedv drawing and a perusal of the following specification.

In the drawing, which is for illustrative 'purposes only:

Fig. 2 is an enlarged section of a portion of the lower end of the bit with one of the cutters in place thereon.

Fig. 3 isa partial section on the line ac3-m3 of Fig. 1 looking in the direction of the arrows.

In thedrawing, 11 is the lower end of a tool joint or coupling secured to the lower end of the drilling string, the coupling 11 being threaded at 12 to receive a threaded projection 13 formed on the upper end of the body 14 of the'roller bit. The side walls of the well are shown at 15, and the bottom lof the well is shown at 16. The body 14 is of elongated form, as shown, and of slightly smaller diameter than the desired bore of the well. Secured at either'edge the'reof is a removable stripj17 which is dove-tailed into the body 14 of the bit. A drilled hole 18 connects a pair of drilled holes 19 and 20 which extend upwardly from4 the lower edges 21and 22 of the body 14 and come municate with a central hole 23 in the projection 12, which in turn registers with and connects to an open hole 24 in the coupling 11, which is in open communication with the interiorof the string of drilling pipe. Secured to the lower end of the body 14 is a projection 25, slightly wider than the body having two cylindrical pins 26 formed on either side thereof.

The pins 26 are machined to form smoothl clinders and the body of the bit is mac ined at right angles to the axis of the pins to form shoulders 27. Each of the pins 26 has an opening 28 drilled therein, the outer end of the opening bein threaded as shown at 29, and the inner en being smooth and of a somewhat smaller diameter than the threaded portion 29. Threaded in the openings 28 are cap bolts 30. Each of these bolts has a head 31, somewhat larger in diameter than the pins 26, a threaded portion 32, fitting tightly in the threaded` portion 29 of the opening 28, a portion 33 of smaller diameter than the portion 32 and having a locking oove 34 out therein, and a small end 35 w ich projects slightly through the projection 25 and ts into a small hole in an inner Washer 36. The inner washers 36 are placed on the pins 26 and are locked in place not only by the end 35 but also by the clamping action of a stationary bushing 37 which is held in place by the clamping action of the cap bolts 30. An outer Washer 38 is etter illustrate the method, of

and the method of attaching the placed between each of the heads 31 and the stationary bushings 37. The washer 36, the bushing 37, and the washer 38 form a removable stationary bearing surface for the cutters 40 and 41, loose bushings 42 turning freely in the borey of the cutters upon the bushings 37. Pins 43 are driven through holes formed in the projection 25 engaging the grooves 34 and locking the cap bolts 30 firmly in place.

rlhe pins 26 are inclined as shown in the drawing, with the horizontal, the outer cutter 41 bearing on a conical surface 50 adjacent to the walls of the hole 15, and the inner cutter 40 lbearing on an inner cone 51 .having its apex at the center of the hole. As the bit is rotated the cutter 40 continually rolls upon and cuts the cone 51, and the cutter 41 continually rolls upon and cuts the cone 50.

The method of operation is'as Jfollows:

' The drill pipe Vbeing rotated by any of the standard methods, and mud being forced downwardly therethrough, this mud passes through the holes 19 and 20, being forced downwardly over the cutters 40 and41, these cutters rolling upon the bottom of the hole and cutting the cones 50' and 51 as previously described. The cutters in their preferred form have a screw thread cut on the periphery thereof. The cutters wear relatively rapidly, but being of simple form they are cheap to produce and can be replaced at a very small expense. 1f desired transverse cuts can be made across the face of the cutteirs 40 and 41 to produce a serrated cutting e e. i

find in practice that one set of bushings will outlast several sets of cutters. The pins 26 and 27 do not wear at all, being protected by bushings 37, and the washers 36 and 38 are readily replaced, these washers, however, wearing comparatively slowly. The long bod 14 steadies the bit in the hole, thorough y mixes' the mud, and greatly assists in diggin through the relatively soft formations. Iglo `dove-tailed edges 17 are readily replaced as they become worn, so that the body 0 pensive portion, can be operated indefinitely, the wearing parts all being replaceable.

The inclination of the cutters is very important, as it is practically impossible to placev a cylindrical cutter in a well unless it is so inclined, due to the' diliiculty of reaching the outer edge of ithe hole with a cylindrical cutter. A cylindrical cutter can not be laced in'a vertical hole, with its axis at an angle of approximatelyr25 lt claim as my invention:

l. A roller bit for use .in an oil well comprising a body, an outer pin and' an inner' pin secured in said body at an inclination to the axis of the well, an outer cutter on said outer pin, and an inner cutter on said inner pin, said pins being so located that Ieaid outer cutter rolls on a path around the outer portion of the bottom of the well, and said inner cutter rolls on a path inside of the path of said outer cutter comprising approximately all of the remainder of the bottom or" the well.

'2. A roller bit for use in an oil well comprising a body, an outer pin and an inner pin secured in said body at an inclination to the axis of the well and approximately pan allel With each other, an outer cutter on said outer pin, and an inner cutter on said inner pin, said pins being so located that said outer cutter rolls on a path around the outer portion of the bottom of the well, and Said inner cutter rolls on a path inside of the path of said outer cutter comprising approximately all of the remainder of the bottom of the Well.

3. A roller bit for use in an oil well eemprising a body, an outer pin and an inner pin secured in said body at au inclination to the axis of the well, a cylindrical outer cutter ou said outer pin, and a cylindrical inner eutter on said inner pin, Said pins being S0 located that said outer cutter rolls on a path around the outell portion ol the bottom of the well, and said inner cutter rolls on a path inside of the path of said outer cutter comprising approximately all of the remainder of the bottom of the well.

if. A roller bit for use in an oil well coinprisinga body, an outer pin and an inner pin secured in said body at au inclination to the axis of the well and approximately parallel with each other, a cylindrical outer eutter on said outer pin, and a cylindrical inner cutter ou said inner pin, said pins being so located that said outer cutter rolle on a path around the outer portion of the bottoni of the well, and said inner cutter rolls on a path inside ol the path of said outer cutter comprising approximately all ot the remainder of the bottom of the well.

ln testin'iony whereof, l here hereunto set my hand at Los Angeles, California, this 27th day of August, 1915.

HUGH A. BARDFICN.

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