US2488003A - Well-drilling tool - Google Patents

Description

Nov. l5, 1949 T. A. cRElGHToN 2,483,003

WELL DRILLING TOOL Filed March 21, 1945 4@ .-F w 45 47 INVENToR. 43. ZOMAS. TGF/@Hmm BW MM A Trae/Vey.

:on the line 3--3 of Fig.. 2.

Patented Nov. 15,` 1949 WELL-DRILLING TOUL Thomas A. Creighton, Long Beach, Calif., assgnor of .one-third to Martha H. Wright, Los Angeles,

Calif.

Application March `21, 1945, Serial'No. 583,929

(Cl. .Z55- 72) 8 Claims.

This invention relates to lwell drilling tools and deals more particularly with well bits for use in the rotary method of drilling. The present-invention is an .improvement in the general type of bit which is the subject of Patent No. 2,1'l9y0l0, issued November '7., 1939.

As set forth in the aboveidentied-prior patent, during a well drilling operation, it sometimes becomes necessary to perform a survey of the well to test the earth formations being drilled, to determine the direction of the hole being drilled, or to gather other information. In the said prior patent the means or core cutter provided `for 'breaking up the earth formation wor `core at the central portion of the vwell bore is subject to being deflected from the core cutting position by instruments used during surveying'operations and is such as to automatically return to cutting position upon withdrawal of Asuch instruments from the bit. s

A working core cutter of the. character `mentioned is necessarily small and during .use is subjected to forces tending to create great wear and often such `as to cause fracture or failure thereof. Need for replacing the core cutter frequently arises before it is .necessaryto replace other-parts of the bit. With the structure of thersaid prior patent such replacement is generally diiiicult and time consuming and can be accomplished properly only with shop facilities. Y It is an object of the present invention to provide a structure vthat facilitates field replacement of a .core cutter of the general type present in the said prior patent and in other similarl structures. Tt is another object of the invention Yto provide a well bitY in which a core cutting `means `with a hinged core cutter is releasably secured in a counterbore at the lower end `of the central ypassage provided through the body of the bit. Threaded engagement is Apreferably provided Vbetween Lthe core cutting means and the body of the bit.

VThe lvarious objects and features of my invention will be fully understood from the following -detailed description of typical preferred forms and applications of my invention, throughout which-'description reference is made to the accompanying drawings, in which:

Fig. 1 is a side elevational viewof a rotary well drilling bit embodyingone kform-of the invention.

Fig. 2 is an .enlarged 'fragmentary longitudinal :sectional view taken as indicated by line 2-2 .of Fig. .1.

Fig. :3 isa .broken detail `sectional view as taken Fig. 4 is a fragmentary bottom plan view as seen in the direction of the arrow 4 of Fig. 2.

Fig. 5 is a view similar to Fig. 2 of another form of drill bit embodying the invention.

Figs. 6 andv 7 are fragmentary cross sectional views taken on the lines 6-6 and 1 1, respectively, of Fig. 5.

Fig. 8 is a broken detail sectional view as taken on the line 8 8 of Fig. 5.

The present invention may be embodied in well drilling bits of various types and constructions. The following detailed description is based onv typical forms of the invention embodied in drag type rotary bits and therefore it is to be understood that the invention is not to be construed as limited or restricted to the specific details that may be shown or which may be described.

The bit construction shown in Figs. 1 to 4, inclusive, provides a bit body I0 having a central vertical opening or bore II extending through it from one end to the other for receiving or passing a surveying instrument A, cutting means I2 on the body I0 for cutting the well bore to gauge, and core cutting means I3 for cutting or breaking away the central earth formation or core left standing by the cutting means I2.

The body In of the bit is preferably in the form of a stem or shank. Typical means, such as a threaded socket -I 5, may be provided to facilitate connection of the bit with a well drilling string. The bore I I is preferably a central through bore or opening and may be reduced in size at the lower end portion of the bit as shown at Ila. This bore serves both to conduct circulation fluid vduring drilling and to pass the surveying instrument A. Means may be provided to assist in locating and supporting the surveying instrument A and may comprise an annular flange I6 on the wall of the bore I I, spaced below the socket I5. The reduced bore IIb formed by the ange together with the reduced bore portion IIal may serve to center and Alocate the surveying instrument A in the bit body I0 or to guide a portion of f the instrument relative to the bit.

The cutting means I2 may comprise cutting blades Il on the lower end portion of the body and may include cutting blades I8 on the upper end portion of the body Ill. The blades I1 may be termed leading or pilot blades and may act to form .an annular out in the earth formations to receive, with suitable clearance, the bit body It. The blades I8 may serve as reaming or bore yenlarging cutters acting to enlarge the well hole formed -by thev :blades all .so vthat .the hole is. of

the desired size and so there is ample clearance for return flow of circulating iiuid.

The core cutting means I3 is provided to remove, cut, or break away the inner or central earth formations of the Well unaffected by the cutters I'I and I8, and, as contemplated, is a unit threaded to the bit body and is provided with a cutter that is retractable or dislodgeable from its cutting position to permit the surveying instrument A to be arranged in or passed through the body bore II to make a well survey.

The core cutting means I3 may comprise one or more retractable cutters or cutting dogs I9. One such cutter is shown in the drawing. According to the invention, means are provided whereby the core cutting means I3 may be easily and quickly removed from the bodyof the bit for replacement and/or repair.

One manner of applying the means I3 to the bit includes an insert or member such as a ring 20 disposed in a seat 2l or seat opening formed in the body I from its lower end, and having threaded engagement with the body as at 22. Threads on the exterior of the ring member enjgage threads on the wall of the seat opening in the body that receives the ring member. The axial bore 23 of the ring member forms an eX- tension or continuation of the bore portion ila in the body II). The seat or seat opening 2l may be of such size as to leave the Wall portion 24 of the body surrounding the ring suiiciently strong to effectively support the means I3 and at the same time allow the ring 20 to be thick enough to accommodate and effectively hold a pivot pin 2-5 for supporting the cutter I9. The inner end of the cutter i9 may be disposed in a notch or seat 26 formed in the ring 2B. The cutter is preferably provided with means normally yieldingly holding it in operation position where it extends to the center of the opening in the ring member 20. One such means is preferably a yielding means and may comprise a torsion spring 2 around the pivot pin 25 and having its ends in engagement with the ring at 28 and the dog at 23. Spring 2l' returns the cutter to working position after it has been depressed or deflected by passage of an object or instrument through the means I3. The cutter YI9 is preferably provided with a blade or cutting edge portion 30, so arranged with respect to the blades I'I as to completely break or cut away the core left by said blades II.

It will be recognized that the cutter I9 is necessarily limited in size and that the necessary details of its design are such that it is `subject to wear and possibly injury before the other parts of the bit are Worn or need replacement.

Should replacement of the cutter I9 become necessary, quick removal of the Worm or broken means I3, and replacement with similar means in good repair, may be accomplished by merely unthreading the means I3 from its seat 2I and threading another like element into its place. Drilling operations may then proceed. In this manner the bit I is given longer life and much time is saved with resultant economic savings.

In other respects the bit of the instant invention functions similarly to those disclosed in the above mentioned patent.

In the form of the invention shown in Figs. to 8, inclusive, the bit may comprise a body 40 having a longitudinal bore 4I, cutting means 42, and one or more retractable cutting means 43. The body 40 may be provided with a threaded socket 44 for connection with a drilling string and the cutting means 42 may follow generally the design of the blades I'I.

In this form of the invention a cutter 45 may be carried by a bar 46 arranged, preferably, in a longitudinal slot 41 in the body 40. In this manner the means 43 may be assembled into the bit from the top end thereof and held in place against shoulders or stops 48 on the body by the pin, on a part of a drill string, engaged in the socket 44. As before described, the cutter '45 may be pivoted to the bar as on a pin 49 and spring means 5B may be provided to normally yieldingly hold the cutter in scraping or cutting position. The above provisions suitably locate the means 43 longitudinally in the body of the bit. To hold the bar against inward displacement the slot 4l may be a dove-tail slot, as shown best in Fig. 7, and the bar 46 similarly shaped to fit the slot. The front or inner wall 5I of said bar may be made'concave to complete the bore 4I. In other vital respects this form of the invention may follow the form shown in Figs. 1 to 4. Replacement of the means 43 may be made easily and with little loss of time.

It will be apparent that the cutting components of the bit will function to eiectively bore a hole and that the center of said hole is removed or broken during drilling by the core cutting means provided in the bit. When a surveying instrument is operated in or through the bit the core cutter may be readily dislodged or moved to a retracted position by the instrument A and upon withdrawal of the instrument A the core cutter will resume a normal core cutting position.

Having described only typical preferred forms and applications of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modications that may appear to those skilled in the art and fall within the scope of the following claims.

Having described my invention, I claim:

1. A well drilling bit including a body having a longitudinal bore, cutting means on the body operable to make an annular cut in the earth formation leaving a central core of earth formation, core breaking means on the body including a cutter operable to cut away said core and retractable by an object passed through the opening, and means releasably connecting said body and said core breaking means including, a longitudinal seat in said body and a member pivotally supporting the cutter of said core breaking means and carried by said seat, the seat being a longitudinal channel in the body and said member being an elongate bar retained in the channel.

2. A well drilling bit including an elongate body having a central longitudinal passage therethrough and a counterbore at the lower end of the passage entering the body from its lower end, cutting means on the lower portion of the body operable tc make an annular cut, member mounted in the counterbore and having an opening therethrough registering with and corresponding in size to the said passage of the body, a core cutter pivotally carried by said member, and means normally yieldingly holding the core cutter in position to act on material left by the said cutting means.

3. A well drilling bit including an elongate body having a central longitudinal passage therethrough and a threaded counterbore 'at the lower end of the passage entering the body from 'its lower end, cutting means on the lower portion of the body operable to make a cut, an annular ma In 4. A well drilling bit including a body havingA a longitudinal bore, cutting means on the body operable to make an annular cut in the earth formation leaving a central core of earth formation, core breaking means, and means releasably connecting said body and said core breaking means including, threads on the body and mating ,threads on said core breaking means, the core breaking means including a pivoted cutter operable to cut away said core and retractable by an object passed through the opening.

5. A Well drilling bit including a body having a longitudinal bore, cutting means on the body operable to make an annular cut in the earth formation leaving a central core of earth formation, core breaking means including, a cutter, a member engageable with the body and means pivotally connecting the cutter and said member so the cutter is operable to cut away said core and is retractable by an object passed through the opening, and means releasably connecting said body and said core breaking means including a longitudinal seat in said body carrying said member.

6. A well drilling rbit including a body having a longitudinal bore adapted to receive an object passed downwardly through the bit, cutting means on the body acting to make an annular cut around a core, core cutting means including a member engageable with the body, a cutter, means connecting the cutter to said member to move relative thereto between a core cutting position and a retracted position, and resilient means normally holding the cutter in the rst mentioned position, and means releasably connecting said core cutting means and said body including, threads on the body and mating threads on the core cutting means, the cutter of the core cutting means being operable to the retracted position by an object passed through the bit.

'7. A well drilling bit including a body having a longitudinal bore adapted to receive an object passed downwardly through the bit, cutting means on the body for making an annular cut around a core, core breaking means for normally acting to remove the core and retractable to an inoperative position by the mentioned object, said latter means including, a cutter, a member engageable with the body, means mounting the cutter on said member to move between a core fcutting and a retracted position, and means yieldingly holding the cutter in the core cutting position, and means releasably connecting said core breaking means and body, said latter means including a longitudinally disposed threaded seat located centrally in said body and a thread on the said member of the core breaking means having engagement with the seat.

8. In a bit of the character described having a cutter supporting body with a central opening therethrough, core breaking means comprising an annular member carried in the body, the opening through said member being in register with and the same size as the opening of the fbody, Vand a resiliently mounted cutter carried by said member, and means on said member releasably engaged with the bit including threads on the exterior of said member and cooperatively engaging threads on the body.

'THOMAS A. CREIGHTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,351,003 Pace Aug. 24, 1920 2,170,716 Higgins, Jr. Aug. 22, 1939 2,179,010 Creighton Nov. 7, 1939

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