US2038792A - Core drill - Google Patents

Description

COREV DRILL ril 28, 1936. Q1. H. HOWARD Er AL.

Original Filed Aug. 7, 1935 Patented Apr. 28, 1936 UNITED ST 'r oFFlcle:Y

CORE DRILL John H. Howard, Huntington Park, and Alfred C. Catland, Alhambra, Calif., assignors to Globe Oil Tools Company, Los Nietos, Calif., a corporation of California 3 Claims.

'Ihis invention relates to a well drilling tool and relates more particularly to a well core drill for obtaining cores or samples of the earth formations. A general object of the invention is to provide a simple practical and improved core drill having a floating or rotatably supported inner barrel for receiving the core.

This application is a division of our application. for 'United States Letters Patent entitled Core drill, led August 7, 1933, Serial No. 684,018.

It has been found desirable to mount the inner core receiving barrel of a rotary core drill in a manner so that it may not rotate with respect to the core when the drill is rotated during the drilling operation. In the core drills that have been introduced having floating inner barrels that may be held against rotation through contact with the core, theinner barrels are usually rotatably supported from their upper ends. Rotatably supporting the inner. barrel of a core drill from its upper end greatly complicates the construction of the drill and necessitates the provision of guiding means and packing means at the lower end of the barrel to prevent the circulation fluid from washing away the core.

An object of the present invention is to provide a core drill having an inner barrel for receiving a core that is rotatably supported at its lower end in a simple effective manner, so that it may be held against rotation through contact with the core when the `drill is rotated during drilling.

Another object of the invention is to provide a core drill including a floating inner barrel whose rotatable mounting at its lower end is entirely within the bit head of the drill whereby the construction is materiallyV simpliiied and whereby thercirculation uid flows directly from the annular space between the inner and outer barrels to the discharge ports in the bit head without interfering. with the rotatable mounting of the inner barrel. l Another object of the invention is to provide a core drill embodying an inner barrel rotatably supported in the bit head and a core catcher independently rotatably mounted in the bit head at the rotatable mounting of the inner barrel.

A further object of the invention is to provide a core drill embodying an inner barrel rotatably mounted at its lower end within the bit head and a core catcher independently supported in the bit head'at the lower end of the barrel for independent rotation and limited longitudinal movement, and having core gripping dogs which (Cl. Z55-72) are positively actuated or forced into the core by upward movement of the drill.

Other objects and features of the invention may be better and morefully understood from the following detailed description of a typical form and application of the invention, throughout which description reference is had to the accompanying drawing, in which:

Fig. l is a side elevation of a core drill embodying the present invention with the principal parts broken away to appear in Vvertical cross section. Fig. 2 is an enlarged transverse ldetailed sectional view taken substantially as indicated by line 2 2 on Fig. 1 and Fig. 3 is an enlarged fragmentary detailed sectional view of the lower portion of the drill illustrating the rotatable.

mounting of the inner barrel and the core Y catcher'.

The core drill provided by this invention includes, generally, an outer barrel IIJ, a bit. head Il Yon the lower end of the outer barrel I 0, an inner barrel I2 for receiving the core cut by the bit head, means X rotatably mounting orV supporting the inner barrel I2 in the bit head II, and a core catcher I3 rotatably supported in the bit head Il.

The outer barrel Ill is an elongate tubular structure adapted to be attached to the lower end of a well drilling string of drill pipe, or the like. The outer barrel I0 comprises a tubular main section I 5 provided at its upper end with a sub IS. The sub I6 has an upstanding screw threaded pin I1 for facilitating connection of the drill with the drilling string. A sub I8 is threaded on the lower end of the section I5 and carries a bit head sub I9.

The bit head I! is attached to the lower end of the sub I9 and is adapted to make an annular j cut in the earth formation and provide a core for reception by the inner barrel I2. The bit head il includesa tubular shoe or body 2U having a plurality of circumferentially spaced cutting blades. Each of the cutting blades includes a pilot portion 2| and a reaming portion 22. The pilot teeth or portions 2| project downwardly directly below the lower end of the bit head body 2t and operate to cut a comparatively narrow annular channel in the formation and form a core which is received in the inner barrel I2 with suitable clearance. The reaming portions 22 of the cutting blades project substantially radially from the bit head body 20 and operate to cut or enlarge the bore to size. The cutting blades core while the upper end'of thebarrel I'2-is charging circulation yeiner.v The bit headV 'body 20 has a central longitudinal opening for passing the core into the inner'barrel I2 and has Va screw threadedV socket 23 in its upperlend for Y receiving the threaded pin on theV lowerrend of the sub I9.-

VThe'Y inner barrel I2 extends longitudinally throughY the outerrbarrel I 3 and is provided to receive the core cut by the bit head II. feature of the invention that the inner barrel I2 is rotatably supported in the bit head II by the means X in a manner so that it may be held against rotation through contact with the core during drilling. Theinner barrelV I2 is an elongate tubular member extending from within the bit head II Vto a point adjacent the sub I6. The

lower end of the barrel I2 is open to receive the closed by a valve I4. The valve I4 preventsthe downwardly flowing circulation fluid from entering the upper end of the barrel l2and is.

adapted to open to permit the `discharrge of fluid from the inner barrel as it is displaced by the Y core entering the inner barrel. The assembly of 30. Y yinner barrel I2 is notprovided with threads its Y inner barrel I2 Vand surrounds a substantial por-V the inner barrel I2 and the valve HIY is more fully Y described and is claimed in our application for Letters Patent Y referred toV above. The inner barrel I2'may not be threaded at any point and; therefore, may have comparatively thin .walls as illustrated throughout Ythe` drawing. Asr the walls do not have to withstand engagement and handling by wrenches, tongs orV other turning: tools, and, therefore,.may be comparatively thin, The core drill provided with the thin-wall .inner barrel I2 `may be proportioned to cut and receive acore ormaximum diameter with respect to the external diameter ofthe drill. The thinwalled inner barrelv I2.may be formed of aflength gof tubingand may be light in weight and inexpensive.

Thefmeans X for rotatably supporting the iin-` nerbarrel I2 mounts the linner barrel in thebit head AI liso that itmay Vbe held against rotation through engagementwith the. core when the drill is being rotated duringdrilling. In accordance with the invention themeans XA includes or provides an kannular recess 25 in. the interiorof the bit head Vbody 23.` The recess 25 is spaced above the lowerlend of the bit head. body 20.and its bottomV or lower end forms an Y upwardlynfacing yshoulder 28..4 Two vertically spaced vannular shoulders 26 and 2'I are provided on the wall of the recess .25. der 2S is normal to the longitudinal axis of the drill and the shoulder 21 is inclined downwardly and inwardly. The lower end of the inner bar- Y rel ,I2V is rotatably supported in the upper portion of therecess` 25iand the core catcherV I3 is supported in the lower portion ofv the recess. v

The inner barrel supporting or mounting means X includes airing or enlargement 29 on the lower'endV of the inner barrel Yfor cooperating with therinterior of the bithead body 25. The enlargement' 29 is preferably welded to the tion of thelower end of the inner barrel.V 'Ihe enlargement 29V projects downwardly from the inner barrel I2Y into'the upper portion ofthe recess 25. The lower end of theenlargement 29 is adapted Vto engage or rotatably bear on the shoulder 26 to limit the downward movement of Vthe inner barrel in the drill and to rotatably` support the inner barrel. The means X provides for the effective transmission of upward thrusts It Vis a- The upper shoul-V from the inher'harrei to the hit head subis when 'Y the engagement of the core with the inner barrel imposes such thrusts on the inner barrel.v A hardened bushing or bearing ring 30 is pressed into an annular recess 3| in the lower endlof Y the sub I9. VThe enlargement 29 is shaped so that its upper portion projects upwardly into this Y ring 3U.

rounds the lower end of the reduced portion of the enlargement V29 whichextends upwardly I free to float during the drilling operation butVv is heldk against lateral movement or wobbling. The enlargement 29 onl the innerbarrel I2 has A bushing 32 is provided on Ythe en- Y Alargement 29 to rotatably bear'upwardly against the lower end of the ring 30. .The ring V32V sur-V 10 `Y extensive Yengagement with the walls of the ref J cess 25 in the bit'head'body.

Y The core catcher I3 is rotatably supported thek bit head IVI so that itmay be heldl againstY rotationV with respect to the core. The core catcher I3 illustrated in the drawing is described and claimed in our Letters Patent entitledCo're,Y

catcher, granted'to usFebruary 11, 1936, and

numbered 2,030,297. .The annular body of the core catcher` I3 is rotatably arranged in the recess f 25 between the shoulder 28 and theupper enclofv ythe recessr33. The core catcher'body includes two rings, an outer ring 35 and aninner ring 36. The opening 38 of the core catcher is in vertical registerandV alignment with the opening 24 in the bit.V

head and is adapted to freely pass the core upwardly into the inner barrel I2.

wardly in the core catcher body from its upper end and continue through the wall of the core catcher bodyto have their lower ends opposing the shoulder 2'I. k Y

Core catching dogs 4I areV pivotally mounted in the slots 39 to project into the core catcher for engaging the core. The pivotal mountings of the Ydogs Y4l include pins 42 which extend through transverse openings in the dogs and havek their Circumfer-V entially spaced sockets orslots 39 extend downopposite end portions received in an annular openingLiB in the core catcher body. The annular opening 43 may be formed by making an annular groove in one of the rings 35 or'3I.V The projecting ends of the dog supporting pins 42 may be flat- Y Vtened toY cooperate with the wall of the annular e opening 43 to prevent rotation of the'pins. Rivets f 44 extend through radial openings in the rings 35 and 36 to securely connect them. The rivets j 4d are preferably positioned to intersect the annular openingY 43 adjacentY the ends of the Ypins 42 and thus preventlongitudinal shifting of the pins.

YThe rivets. may be such that they maybe'V drilled outto permit disconnection of the-rings Y 35 Vand 36Y and allow V,the removal of the pins l42 nThe core` projectinto the and dogs 4I for replacement, etc.V catcher dogsAI are adapted to opening 38 of the core catcher to grip andsupport the core. Y' 4 I converge to comparatively sharp edges 46. The slots 39 are proportioned to receive the dogs 4I so V The upper and lower sides of the dogs that the dogs may pivot to up inoperative :posif tions Where they doV not interfere with the core;

The dogs -4I are of different lengths wherebysome of them are capable of effectively gripping and supporting hard cores,while others are adapted to bite into and support cores of softer formations. The longest oi the dogs 4I are such that they may support cores which are broken or shattered to prevent such cores from being lost when the drill is withdrawn from the well. The longer dogs 4I may project upwardly beyond the core catcher body when in the inoperative positions and the opening 29a is proportioned to receive their upper ends when in these positions.

In accordance with the invention means is provided for normally yieldingly urging the dogs 4| downwardly and inwardly and means is provided for positively pivoting the dogs downwardly and inwardly into engagement with the core when the drill is raised. The means for yieldingly urging the dogs 4I into contact with the core comprises torsional springs 49 surrounding the pins 42 in notches 48 in the dogs. The springs 49 each have an end reacting against the body of the core catcher and an end reacting against a dog 4| to normally tend to pivot the dogs downwardly and outwardly. The means for positively pivoting the dogs 4I downwardly and outwardly into the core when the drill is raised also operates to dependably support the pivoted ends of the dogs on the body 20 of the bit head. This dog operating and supporting means comprises a cam part or shoulder 52 on the pivoted end of each dog 4I for cooperating with the shoulder 21. In accordance with the invention the core catcher is proportioned to have limited relative longitudinal movement in the recesses 25 and 33 and the cam parts 52 cooperate with the shoulder 21 to pivot the active ends of the dogs downwardly and outwardly into the core when the drill is raised. With the dogs 4I in the projected core supporting positions the upper ends of the cam parts 52 cooperate with the lower end of the ring 35 whereby the dogs are dependably supported. Flat faces 50 are provided on the dogs 4| to cooperate with the lower ends of the slots 39 when the dogs are in the core supporting positions. The engagement of the cam parts 52 with the lower end of the ring 35 and the engagement of the faces 50 with the lower ends of the slots 39 positively limits the downward pivoting of the dogs and provides for the dependable supporting of the dogs when they are carrying the core.

The invention includes improved means for circulating or conducting the drilling iluid or rotary mud directly from the annular space S between the barrels I0 and I2 to passages in the bit head I I. In accordance with the usual practice rotary mud or circulation fluid is pumped downwardly through the drilling string and iiows downwardly through the annular space S between the two barrels. Downwardly and outwardly extending ports BIJ are provided in the enlargement 29 of the inner barrel to conduct the circulation fluid from the lower end of the space S to an annular channel 6I in the bit head body 20. The ports 60 are spaced a considerable distance above the lower end of the enlargement 29 and extend below or under the bushing ring 32. The channel 6I is also spaced a substantial distance above the shoulder 26 and the lower end of the` enlargement 29.

The annular channel 6I is provided to distribute the fluid to a plurality of vertical discharge passages 62 in the bit head body 20. The passages 62 discharge downwardly at the lower end of the bit head body adjacent or immediately in front of the cutting blades. The passages 62 may be rectangular in transverse cross section and their outer sides may be closed by replaceable plates 63. It is to be particularly noted that the circulation fluid or rotary mud passing through the ports 60, channel 6I and passages 62 does not in any way interfere with the freedom of the inner barrel I2 or the core catcher I3. The fluid flowing through the passages has no tendency to mud up the rotatable mounting means X or the core Y catcher I3.

During operation the core drill is operated on the lower end of a string of drilling pipe in the usual manner. 'Ihe circulation fluid is continuously pumped down through the drilling string to discharge from the lower ends of the ports 62. The pilot portions 2| of the cutting blades make a comparatively narrow annular channel in the.

earth formation cutting a core which is received in the opening 24 and the inner barrel I2. As the core enters the drill the dogs 4I are pivoted upwardly into the slots 39 and the engagement of the dogs with the core during the drilling operation retains the dogs in this inoperative position. The springs 49 yieldingly urgethe. dogs against the core so that the core catcher I3 may be held against rotation. The core catcher I3 in being independently rotatably mounted in the bit head I I may be held against rotation through the engagement of the dogs 4I with the core, without endangering the dogs and without destroying or cutting away the core. As the core catcher is mounted to remain stationary with respect to the core there may be but slight clearance between the wall of the core catcher body 3 and the core, so that there is little or no danger of the core slipping back through the core catcher when the drill is raised and removed from the well. As the core is cut or formed by the bit head I I it is received by the inner barrel I2 and the frictional engagement of the core with the interior of the inner barrel may hold the inner barrel against rotation.

The means X supports the inner barrel I2 at its lower end, so that it may have but little tendency to turn or rotate as the drill is rotated, when it is in contact or engagement with the core. It is to be noted that the inner barrel I2 and the core catcher I3 are independently rotatably supported in the bit head II so that the rotation of either one will not affect the other. The location of the ports 60 and the annular channel 6I is' such that the downwardly flowing circulation fluid does not deposit sand or solid matter in the rotatable mountings of the inner barrel I2 or the core catcher I3. Any circulation fluid that may leak around the enlargement 29 merely acts to lubricate the mounting X. The inner barrel I2 is light in weight and is eiTectively rotatably supported by the means X so that a minimum amount of engagement or contact of the inner barrel with the core is required to hold the inner barrel against turning.

When a core of sufficient length has been cut the drill may be raised and withdrawn from the well. Raising of the drill results in upward movement of the bit head I I relative to the core catcher I3. The engagement of the dogs 4I with the core yieldingly holds the core catcher against upward movement during the initial raising of the drill. In this manner the shoulder 21 is brought into actuating contact with the cam parts 52 causing the dogs 4I to be pivoted downwardly and into the core. Upward movement of the drill thus results in full positive actuation of the core gripping dogs 4I so that they obtain rm holds on the bular bit head kon the'lower end of the outer bar- Y inner barrel, and a core catcher movably support- Y ed'in the last mentioned recess and the communicoreandcause'` the coreto be broken away from the'formation as theV drill is raised. Theinde-V pendent supporting of the inner barrel l2 on'fthe ,Y shoulder 26 prevents'the inner barrelY I2 or its enlargement 2,9 from interferingY with the proper operationiof the core catcher I3.

- Having described only a typical form'and application of our invention, We do not Wish to be Y Y limited or `restricted to the speciiic form and ap-V plication herein described, but wish to'reserve to ourselves any changes or Variationsthat may appear Vto thoseskilled in the art'or fall within Vtheiscope of the following claims.

Having described our'invention, we claim: V1. kA core drill including, anV outer barrel, a turelthe bit head having an internal'recess, an inner barrel'extending through and spaced from the'interior of1 the outer barrel, an enlargement Y on theinner barrel rotatable in therecess to rotatably supportV the inner barrel in the bit head, there being a recess'in the interior of the enlargement joining'the recess in the bit Yhead and hav ing Va diameter greater than the opening in the eating portion of the recess inthe bit head.

2. A core drill including, an outer barrel, a bit head on the lower end of the outer barrel having anrannular internal recess, an`upward1y facing shoulder'on 'the wall of the recess, an'innei" barrelVY extending through the outer barrel, an enlarge'-V Y ment on the inneribarrelin the recess andA adapted to have its lower end rotatably bearon said mentioned recess and said portion of the first'l mentioned recess.

' 3. In a core drill, a bit head for making 'anv anular cut and having an opening for'receiving the core, there being an upwardly facing shoulder in the opening, a member on the upper end ofnthe head presenting a downwardly facing" shoulder spaced from and opposing the first named shoulder, an inner barrel, a projecting bearing on the lower portion of the` inner barrel rotatable in the said opening, the lowerend of the bearing being adaptedl to bearron the iirst' named shoulder, the bearing having a portion ofv reduced diameter rotatably bearing on the interior surface oi said member and a shoulder' op' posing the second named shoulder, a bearing ring Yon the second named shoulder, and a bearing ring on the shoulder of the barrel adapted to co-Y operate with the rst mentioned ring.

JOHN H. HOWARD. ALFRED C. CATLAND.

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