US1785405A - Core-drilling bit - Google Patents

Description

Dec. 16, 1930. y R. R. cANDl-:E E1- AL 1,785,405

CORE DRILLING BIT Filed oct. 5, 1927 y N V//////// E Ji: ATTORNEY.

Patented Dec. 16, 1930 l UNITED STATES .PATENT OFFICE RAPHAEL ROGERS CANDEE, OF MCEITTRICK, AND OSCAR FRED HARDING, OF

COALINGA, CALIFORNIA conn-Dramma Brr `Application led October 5, 1927. Serial No. 224,197.

This invention relates to deep well drilling tools and more especially to a rotary, core cutting tool.

It is highly desirable in the drillingof deep wells that accurate logs be kept of the actual formation which is encountered, strata by strata. With drills not taking a core the ine cuttings mix with the .circulating fluid to' such an extent that only rough estimates can be made as to the probable depth of the strata from the top of the hole and of the thickness of the strata itself. This guess work of logging is very deficient where the deep strata may each be quite thin.

Various types of core taking drills have been devised and quite successfully used. With these diiculty is experienced in removing the core.

The present invention has for an object to '20 take a core of any desired length. A further object is to provide for the ready removal of the core from the drill barrel.

Another deficiency of various forms of core drills is the inability to obtain a good specimen when the drill is running through rather soft formati on which has the tendency to muck and flow down out of the drill when this is pulled out. Therefore another object is to provide means for effectively retaining a core specimen of a soft formation.

An additional object is to provide a drill constructed and designed to cut an annular swarth around a dead center Zone and to form a core on the center and to provide means for by-passing the top of the core in fragments out through the side of the drill stem continuously during operation of the drill after a predetermined length of core has been cut; it being understood that the core shall be so cast off only in cases where the log of the formation is undesired.

There are other objects and advantages and features of construction and combination, and these will be made manifest in the following specification of the herewith illustrated em bodiment; it being understood that modifications, variations and adaptations may be resorted to within the spirit, scope and principle of the invention as it is more directly claimed hereinafter.

. Figure 1 is an axial section of the tool. Figure 2 is a bottom plan of the bit. Figure 3 is a side elevation of the bit. Figure 4 is an end view of a core barrel sleeve section.

Figure 5 is an axial section of the assembled barrel of sleeve and cuff parts.

Figure is an end view of one of the split cuffs.

Figure 7 is a centering ring.

Figure 8 is a plan of the core barrel trap.

Figure 9 is an axial section of the trap.

Figure 10 is a detail, on substantially full plan of the core barrel head scale, of a fragment of the trap showing a mode of mounting a trap finger.

In its illustrated form the tool includes a stout bottom piece or bit body 2 having a tapered top pin 3 for attachment to a drill collar or section 4. The bit body 2 is cen- 70 trally bored and has an intermediate, annular shoulder or ledge 5.

On the bottom face of the bit body 2 is an inner, annular series of cutters 6 having cutting, end lips 6a and extending inwardly 75 along the bit bore and presenting longitudinal cutting edges 6b leaving a central core of the penetrated formation and which core stands in the bit bore as drilling proceeds.

Extending beyond the bit body 2 is a circle 80 of reaming cutters 7 having advance, bottom cuttingedges 7a which are of a length to overlapthe orbit of the inner cutters 6. The cutters 7 have a substantial helical pitch on the body 2, receding from the cutting edges 7*. 85 As the running drill goesdown the core passes into a trapping means in the body 2 which is for the purpose of grappling in the core when the drill is pulled from the hole. The trap, as shown, includes a cage wall 10 90 provided with inwardly and upwardly inclined spring-leaf fingers -ll whose lower ends are riveted at 12 in openings 13 in the cage wall so that the fingers-may lie back flush when the full size body of core is em- 954 braced. Then the tool is pulled up the finf i gers spring in and take hold or if the formation is soft the fingers will flex in to form a bottoni for the 'cage and thus retain a very material port-ionof the penetrated formation.

The fingers, as shown, have a helical pitch reverse from direction of rotation which is for the purpose of facilitating vrotation of the cage while the fingers are engaging a hard core; the fingers having a nut-like effeet advancing on the core.

The cut core passes from the bit body 2 and pin 3 up into the hollow collar 4 and this is provided with a removable core receiver or barrel forming one of the features of this invention. This ,barrel is 'made of a combination of parts4 constructed and arranged to greatly facilitate the extraction of the core and includes a ferrule having a base 15 seating on top of the trap wall 10 and snugly fitting the body bore so as to close off water passage at aline below a series of water holes 2f. Above the base 15 the ferrule is reduced to a cylinder 15a to form a space thereabout to the holes 2a for water and is again reduced at 15b above shoulder 15 to snugly receive a short length of tubing or sleeve 16 of greater length than the ferrule portion 15".

Any desired length of barrel vmay be built up by abutting a number of the sleeves 16, as determined by the length of drill collar 4 or multiples thereof. The abutted sleeves 16 are detachablyalined by suitable means here shown as including a line of inside sections or cuffs 17 which'are of resilient metal and split at 17a along one' side. The cuffs have a diameter, when free, greater than the inside diameter of the sleeves 16 and are of' `Acelve the core as itis cut by advance of the When the tool is pulled, the sections 16-17 are successively removed from the core. To accomplish th1s the sections have pairs of wrench engaging holes 20, which are soA disposed as to never register and therefore prevent water liow from sleeve into culi. First, a sleeve is pulled off endwise and lthen the next cuff is pulled to just clear the next sleeve following which the released cuff will spring open fully loose about the enveloped core.

The free cuff is then easily pulled endwise ter, non-cutting zone by leaving a core on center and where it is not desired yto retam the core for log record we provlde vmeans to automatically discard the core by passing it ofi', in small fragments, and out to one side of the drill Where it is quickly abraded down by the side wall of the hole during rotation of the drill.

The discard means shown includes an upper joint 22 having a pin for the collar and a top box for attachment to the upper drill rbd string (not shown). The joint 22 is chambered to form a Water passage to the collar 4 and receives the upper end of the top core barrel sleeve 16. A iue or deflecting conduit 23 leads from the upper end of the core barrel and discharges at a side aperture 24. The adjacent ends of the conduit 23 and top sleeve 16 are centered and supported by suitable means here shown as a seat ring 25 having marginal water ports 25a to permit circulation to the collar 4. The passageway in the conduit 23 pitches at an an le and therefore when the head of the core impinges on the opposed inclined face of the conduit the weight of the whole tool is effectively useful to transversely break 0E the core, if it is of hard stone.

The ring 25 may be of hard metal and form a fulcrum for the core when the tool acts on the head of the core to break it olf for deflection into the discarding conduit 23.

If the conduit is of removable, renewable installation it can be buttressed by a backing block 27.

The invention claimed is:

1. In combination, in a drill, a bit body head having a series of helical reaming blades with straight bottom cutting edges extending under the bottom of the body and a series of bottom cutting blades; the bottom edges of both series of blades .lying in a common plane.

2. In combination, in a `drill, a bit body head having a series of helical reaming blades with straight bottom cutting edges extending under the bottom of the body for about one-half of the radius and which edges lie on lines tangential to the bit center and at such an angle as to sweep the cuttings inward toward the c nter and an inner set of bottom cutters wit\ edges on the same bottom plane of the outer`-blade.

3. In combination, in a drill, a hollow center bit body having a series of helical reaming blades with straight bottom cutting edges extending under the bottom of the body and which edges lie on lines tangential to the bit center and positioned to sweep the cuttings inward, and an inner series of bottom cutting blades with straight bottom edges which lie tangential to the center and pitch in a reverse direction to the bottom edges of the rea-ming blades; the plane of each blade of the inner series lying at an angle of about 60 from the radial line intersecting its nose, and said inner blades overlappin the orbit of the outer blades and all bla e edges being in a common bottom plane.

4. A drilling tool including a core forming 5 bit, a core trap cage seated therein, a drill' collar detachably secured to the bit stem, a string joint removably attached to the collar, a sectional barrel having a base feriule bearing against the said ca e and having a top 10 section seating in the sald joint and whereby the barrel is clamped in place, and a string of split, self-opening core sleeves lining the barrel in broken joint relation and friction holding Contact. 15 RAPHAEL ROGERS CANDEE.

OSCAR FRED HARDING.

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