US1923486A

US1923486A - Core drill

Info

Publication number: US1923486A
Application number: US538211A
Authority: US
Inventors: John H Howard
Original assignee: Globe Oil Tools Co
Current assignee: Globe Oil Tools Co
Priority date: 1931-05-18
Filing date: 1931-05-18
Publication date: 1933-08-22
Anticipated expiration: 1950-08-22

Description

Aug. 22, 1933. J. H. HOWARD CORE DRILL Filed May 18 1931 2 Sheets-Sheet l J. H. HOWARD Aug. 22, 1933.

CORE DRILL Filed 'May 18,

lll'.

Patented Aug. 22, 1933 CORE DRILL John ll. Howard, Huntington Park, Calif., as-

signor to Globe Oil Tools Company, Los Nietos, Calif., a Corporation of California Application May 18, 1931. Serial No. 538,211

8 Claims.

This invention relates to a well tool, and relates more particularly to a core drill for obtaining a core or sample of the formation in a well bore. It is a general object of the present invention to provide a simple, practical, and improved core drill for use in connection with the rotary method of well drilling.

Another object of the inventionis to provide a core drill having novel and effective means l for handling the circulation huid. The tool provided by the present invention includes an inner cutter and an outer cutter and has an annular iluid passage between the two cutters that discharges the circulation fluid into the bottom of the well bore in a manner so that it does not cut out or wash out the core being taken.

It is another objectof the invention to provide a well tool of the character mentioned in which the inner cutter or core cutter proper projects downwardly beyond the outer cutter and is formed so as to protect the. core against disintegration by the circulation fluid.

It is another object of the invention to provide a core drill of the character mentioned in which the inner and outer cutters overlap in their action on the formation so as to remove all of the formation at the bottom of the well bore with the exception of the central core which is re. ceived and retained within the core barrel. The formation and arrangement of cutting parts included in the present invention positively prevents the production of ns or projections of formation in the bottomv of the well bore in the :1,5 event that the edges of the cutting teeth or cutting parts wear away. It is an object of the invention to provide a core taking tool of the character mentioned in which the inner and outer cutters are independ- 43 ently and removably mounted so as to be readily replaceable and/or exchangeable to adapt the tool for use in various formations.

Another object of this invention is to provide a core. drill of the character mentioned in which barrel are vertically slidable as a'unit relative to the outer barrel and outer cutter. It is a feature of the present invention that the inner cutter carried by the corev receiving barrel may pass bo ahead of the outer cutter when the tool breaks through a hard formation into a soft formation so as to prevent loss of the core.

Alfurther object of the invention is to provide a novel and effective means for catching or retaining the core and for cutting off the core'.

Other objects and features of the invention the inner cutter, the core catcher, and the core (Cl. Z-72) will be best and more fully understood from the following detailed description of a typical form and application of the invention, throughout which description reference will be had to the accompanying draWings,`in which:

Fig. 1 is a side elevation of the tool provided by the present invention, showing it in operation at the bottom o f a well bore on the end of an operating string of pipe. Fig. 2 is an enlarged vertical detailed sectional view of one embodiment of the invention, showing it in operation within the well bore. Fig. 3 is a bottom plan view of the tool, be ing a view taken as indicated by line 3-3 on Fig. 2.' Fig. 4 is an enlarged transverse detailed sectional view taken as indicated by line-4 4 on 70 Fig. 2. .Fig. 5 is an enlarged transverse detailed sectional view taken -as indicated by line 5--5 on Fig. 2. Fig. 6 is an enlarged side elevation of the lower end part of the tool. Fig. 7 is a vertical detailed sectional view of the embodiment of the invention illustrated in Figs. 2 to 6 inclusive, being a view taken as indicated by line 7 7 on Fig. 6 showing the core cutting dogs in the actuated or core cutting and supporting position. Fig. 8 is a vertical detailed sectional view of the 80 other embodiment of the invention.

The drills or tools provided by this invention are intended to be employed for obtaining cores or samples of the formation at the ybottom of a well bore, for example, at the Vbottom of an oil well or gas well. The invention -provides two forms or embodiments differentiated from each other principally in the form or type of core catcher or core retaining means. The form of the invention illustrated in Figs. 1 to l inclusive `of /90 the drawings includes a core catching and retaining means that is operable to cut off the core or sample on the formation obtained in the core barrel and to hold or retain it in the core barrel, while the form of the invention disclosed in Fig.' 8 includes a core catching means consisting 'of sets or series of spring fingers for gripping and holding the core passed into the core barrel.

The embodiment of the invention disclosed in Figs. 1 to 7 inclusive of the drawings includes, generally, an outer barrel 10, a bit head or outer cutter 11 carried at the lower end of the outer barrel 10, a core retaining barrel or inner barrel 12 within the barrel 10, an inner cutter 13 carried at the lower end of the inner barrel or core barrel 12, and core catching means 14.

The outer barrel 10 constitutes the body or main portion of the tool and is an elongated tubular member surrounding the core barrel 12 and carrying the outer cutting means 11. The outer barlower end of a string of drill pipe P and may be connected with the operating string in any suitable manner. In the particular case illustrated in the drawings, the upper end of the outer barrel 10 is screw-threaded into the lower end of a sub l5. The sub may be provided at its upper end with a screw-threaded pin 16 for connecting with a tool joint section or coupling member 17 on the lower end of the string of drill pipe P. The outer barrel 10 may be of any suitable length, and its lower end may be screw-threaded into a tubular connecting member or sub 18.

'I he outer cutter or main cutting means 11 is carried at the lower end of the outer barrel 10 and is provided to make an annular out in the formation. In accordance with the present invention, the main cutting means 11 is removably carried at the lower end of the outer barrel 10. In the present embodiment of the invention, the outer or main cutting means 11 includes a body 19 and a bit vhead 20. The body 19 is in the nature of a tubular connecting member or coupling for mounting the bit head 20 on the lower end of the' sub 18. It is to be understood that the bit head 20 may-be attached directly to the lower end of the outer barrel 10 if desired. The body 19 may be of substantially the same internal and external diameter as the sub 18 and may have a screw-threaded connection 21 with the lower end of the sub. The cutter or bit head 20 is annular or tubular in its general configuration and is removably attached to the body 19. The bit head 20 is provided at its upper end with a socket 22 for receiving a screw-threaded` pin 23 on the lower end of the body 19.

A plurality of outwardly projecting cutting parts or blades 24 is provided on the bit head 20. There may be any suitable number of cutting blades 24 and they may be equally or symmetrically spaced around the bit head. In the case illustrated in the drawings, there are four equally spaced cutting blades 24 projecting outwardly from the bit head 20. The blades 24 are inclined or pitched downwardly and forwardly, relative to the direction of rotation of the tool when in operation, and are provided with outer cutting edges 25 for engaging the formation at the walls W of the well bore. The outer cutting edges 25 maybe at substantially uniform distances from the vertical axis of the tool. The blades 24 are provided with lower cutting edges 26 for acting on the formation at the bottom of the well bore to make an annular cut. The lower cutting edges 26 may be substantially radial relative to the vertical center of the tool or may extend slightly forward and outward from the bit head. I Y

In the preferred construction, certain of the cutting blades 24 are longer than the remaining blades so that their lower cutting edges 26 are lower or spaced below the cutting edges of the other blades. In the particular case illustrated in the drawings, one pair of diametrically opposite blades 26 project some distance downwardly from the lower end of the bit head 20 to have their lower cutting edges 26 some distance below the lower end of the bit head, while the other two diametrically opposite blades have vtheir lower edges 26 at or adjacent the lower end of the bit head. It will be apparent that the cutting edges 26 of the two longest blades 24 act on the formation at the bottom of the well bore before the cutting edges of the other blades; and, upon the long blades becoming worn, the shorter blades may act on the formation at the bottom of the 1,923,486 rel 10 is adapted to be carried or operated on the bore. The cutting edges 26 of the several blades are` preferably inclined downwardly and outwardly toward the walls W of the well bore to provide for rapid cutting of the formation and so as to carry the cuttings toward the peripheral walls of the well bore. f

The bottom or active cutting edges 26 of the several blades 24 extend inwardly to the interior of the bit head 20 or to points below the inner walls of the bit head 20. The two shorter blades 24 are provided with cutting teeth 27. A tooth 27 is provided on each of the shorter blades 24 at the inner end of its cutting edge 26. The teeth or cutting parts 27 project downwardly from the lower end of the bit head ,2D so that their lower cutting edges may be in substantially the same horizontal plane as the cutting edges 26 of the longer blades. The lower edges of the teeth 27 may be beveled or sharpened and may be substantially normal to the longitudinal axis of the well borepand tool. The upper edges 28 of the blades 24 may be inclined downwardly and out-` wardly to facilitate withdrawal of the drill from the well bore.

'Ihe inner barrel or core barrel l2 is provided to receive and retain the core C and is arranged longitudinally within the outer barrel 10. The core barrel '12 is centrally disposed within the outer barrel 10 and is of smaller diameter than the outer barrel l0 to provide an annular fluid passage F between the'two barrels. In accordance with the standard practice, the core barrel 12 may be comparatively long and may be provided at its upper end with a means for discharging fluid when receiving the core C. A suitable relief or discharge valve may be provided on the upper end of the core barrel 12 to permit displacement of fluid from the core barrel upon the core being passed into its lower end. In the particular embodiment of the invention disclosed in the drawings, a tubular cap 29 is screw-threaded on the upper end of the core barrel and a ball 30 is provided to control the passage of fluid through the cap. A crown 31 is mounted on the cap 29 around the ball 30 to prevent displacement of the ball.

It is a feature of the present invention that the core barrel 12 and the parts associated therewith are longitudinally or"vertica1ly movable relative to the outer barrel 10. Means is provided for 125 slidably guiding and centering the upper end portion of the core barrel l2. A plurality of spaced guides or splines 32 are provided on the inner walls of the outer barrel 10 to slidably engage the cap V29. The splines32 operate to slidably 130 guide and center the core barrel within the outer barrel 10 and are spaced apart so as to permit the free downward passage of the fluid through the annular spaceF.

The inner cutter or core cutting means 13 is 135 provided to make an annular cut in the formation at the bottom of the well bore within the annular cut made by the blades 24. The inner cutting means 13 is carried on or connected with the lower end of the core barrel 12 and, in accordance with the invention, is removably connected with the core barrel. In the embodiment of the invention being described, the inner cutting means 13 includes an' elongated tubular r member or body 33 attached to the lower end 14" of the core barrel 12 and carrying the core attaching means 14. The lower end of the core barrel 12 is screw-threaded into a socket 34 in the upper end of the cutter body-33. The body 33 is preferably of substantially the same internal and external diameter as the core barrel 12 so as to provide an annular space or continuation of the uid passage F downwardly through the outer body 19 and bit head 20. In accordance with the invention, the cutter body 33 projects downwardly beyond the lower end of the bit head 20 and is provided at its lower end with the cutting means 13, as will be hereinafter described.

The body 33 may have a loose or sliding connection with the outer bit head 20. A plurality of spaced outwardly projecting lugs are provided on the body 33 to slidably fit longitudinal slots 36 in the interior or inner Wall of the bit head 20. In accordance with the broader aspects of the invention, the various features of the invention may be embodied in a tool in which the body 33 has a rigid connection with the bit head 20, for example, a connection in which lugs on the body 33 are immovably held in sockets or slots in the bit head 20. In the specic embodiment of the invention disclosed in the drawings, the lugs or projections 35 are slidable longitudinally or vertically in the slots 36 so that the assembly of the core barrel 12 and the cutter body 33 has limited longitudinally movement relative to the outer barrel l0 and parts connected therewith. The end of the connecting pin 23 constitutes the upper ends of the slots 36, and the upper ends of the lugs 35 are adapted to engage the lower end of the pin 23 to limit upward movement of the body 33 and core barrel. The lower ends of the lugs 35 are adapted to engage the lower walls` or bottoms of the slots 36 to limit the downward movement of the core barrel and body 33 with respect to the outer barrel 10 and bit head 20. The lugs or projections 35 are sutilciently heavy to effectively transmit the rotational strains from the bit head 20 to the cutter body 33 vduring operation or rotation of the tool and to support the core barrel and core during withdrawal of tl.e tool from the well bore.l

Y The cutting par ts on the lower end of the cutter body 33 are in the nature of a plurality of cir' cumferentially spaced blades or teeth 37. The cutting teeth 37 project downwardly from the lower end of the body 33 and are inclined downwardly and forwardly relative to the direction of rotation of the tool. The cutting parts or teeth 37 project downwardly below the cutting edges 26 of the lowest blades 24. The lower edges 38 of the teeth 37 may be beveled or sharpened to effectively cut the formation and may be substantially normal relative to the Vertical axis of the tool. In accordance with the invention, the cutting teeth 37 project radially inward from the interior of the body 33 so as to cut or trim the core C to a size to readily pass upwardly into the core barrel l2. Further, certain of the cutting parts or teeth 37 project outwardly from the exterior of the body 33 suiicient distances so that their outer edges are in vertical planes spaced outwardly of the vertical planes occupied by the inner edges of the blades 24 and, accordingly, so as to have greater active or cutting radii than the blades 24. In this manner, the cutting action of the blades 24 and the teeth 37 overlap to ensure the complete cutting of the formation at the bottom of the tool so that projections cannot remain on the formation to project upwardly between the body 33 and the bit head 20. The wider cutting teeth 37, i. e., the cutting teeth which project outwardly beyond the inner edges of the blades 24, are adapted to extend into slots or sockets 39 provided in the lower end of the bit head 20 when the body 33 and core barrel 12 are in the up position with respect to the bit head 20. The slots 39 are adjusted to pass these larger teeth 37 when assembling the tool. The cutter body 33 extends into the annular cut made by the teeth 37 so that the iluid discharge downwardly through the annular passage F cannot Wash out the bottom of the cylindrical core C' cut by the teeth 37.

The core catching or core retaining means 14 is carried by the body 33 and includes a row or series of leaf springs 40 for engaging the core4 C, and a plurality of pivoted dogs 41 for cutting and supporting the core. y'The springs 40 may be attached to or carried by a ring 43 arranged in the lower en d of the socket 34 and retained in position by the lower end of the core barrel 12. The lower ends of the springs 40 may be riveted or otherwise attached to the rings 43, and the springs extend upwardly and inwardly from the ring, asl illustrated throughout the drawings. During passage of the core C into the barrel, the springs 40 are ilexed backwardly or outwardly and, upon the tool being moved upwardly to withdraw the core C, their upper edges bite into the core, as illustrated in Fig. 7 of the drawings.

'll'he pivoted dogs 41 are pivotally mounted on the interior oi the body 33 and are operable to cut 0E the core C and to support or aid in supporting the core. The lower or outer ends of the dogs 41 are pivotally mounted in the lower ends of vertical recesses or slots 42 formed in the inner walls of the body 33. Pivot pins 44 extend through the lower ends of the slots 42 and openings in the dogs to pivotally attach the dogs to lthe body 33. In the preferred construction, the

'ends of the dogs 41 co-operate with the recesses lli 46 so that the thrusts or strains to which the dogs 41 may be subjected are directly transmitted to the body 33 and do not subject the pivot pins 44 to excessive strains. core C into the core barrel 12, the lugs 41 are in up positions where their major portions are disposed within the slots 42. Spring means is provided for urging the dogs 41 downwardly and inwardly to bite into the core. Aleaf spring 47 is mounted on the inner wall of each recess or slot 42 to normally urge the dog 41 into engagement with the core C.

It is believed that the operation ol' the tool illustrated in Figs. 1 to 7 inclusive of the drawings will be readily apparent from the foregoing detailed description. As the tool is rotated and ied downwardly into the formation, the lower cutting teeth 37 operate to make an annular cut in the formation to provide the cylindrical upwardly projecting core C. The lowermost cutting edges 26 of the outer blades engage the formation at the bottom of the bore to make an annular cut During passage of the around the cut made by the teeth 37. It is to be noted that certain of the blades v37 make a cut in the formation having a larger outside diameter than the inside diameter made by the cutting blades 24. In this manner, the teeth 37 and the blades 24 overlap in their operation or action on the formation to positively ensure the complete cutting away of the formation at the lower end of the bit head 20. The outer edges 25 of the blades cut and engage the walls of the well bore so that the tool does not have any eccentric or undesirable motion, thus ensuring smooth operation of the drill. The circulation fluid is passed downwardly between the inner and outer core cutters through the passage F to discharge downwardly around the projecting end of the body 33. The fiuid discharged at the lower end of the tool is eective in washing the cutting blades 24 and the cutting teeth '37. The downwardly projecting body 33 prevents the discharged circulation uid from striking against and washing out the core C being cut by the teeth 37. During normal operation, the body 33 is in an up position where the lugs 35 are in engagement with the lower end of the pin 23 so that the teeth 37 are Apositively fed into the formation. In the event that the drill passes through or breaks through a hard formation into soft formation, the body 33 and parts connected therewith are free to drop or advance downwardly ahead of the cutting means 11 so that the core will not be destroyed or lost.

When it is desired to remove the tool from the well, the string of pipe P may be drawn upwardly so that the bottom ends of the slots 42 come into engagement with the lower ends ofthe lugs 35. The cutter body 33 and core barrel 12 are then moved upwardly together with the outer barrel 10. Upon upward movement of the tool, the spring fingers cut or bite into the core C and the dogs 41 bite into the core C. If desired, the

tool may be rotated after or when an upward strain is exerted on the string P so that the dogs i1 may cut off the core C. After the core C has been broken or cut from the formation at the bottom of the core, the dogs 41 are operable to assume substantially horizontal positions where they engage under the core and support the core within the barrel 12. It is particularly noted that the invention provides a core drill in which a free annular fluid'passage is provided between the inner andouter barrels to pass fluid downwardly between the inner and outer cutters. The inner assembly is connected with the outer assembly in an effective manner without the use of screw-threaded connections and without the use of annular shoulders or abutting parts which might materially interfere with the downward circulation of fluid between the two barrels. The

' lug and slot connection between the body 33 and the outer bit head 20 permits the provision of the annular fluid passage F and provides for the effective transmission of the operating strains from the body 33 to the outer assembly. o

In the embodiment of the invention illustrated in Fig. 8 of the drawings, the outer barrel 10 and 4the outer cutting means 11 may be identical with those described above, and the, core barrel may be similar to the core barrel 12 described above. In this form of the invention, the core catching means 14B includes two annular rows or sets df spring fingers 60. The upper set of spring fingers 60 may be mounted in the same manner as the fingers 40 described above, i. e., 'they-may be carried by a\ ring 61 arranged in the interior of the tool and held between the lower end of thev core barrel 12 and a shoulder 62. In the conwalls of the sub 63 so that a ring 61 is carried by j the member or sub 63. The sub 63 has a pin 64 on its lower end screw-threaded into a socket 65 V in the upper end of the cutter body 33a. The lower set of spring fingers 60 for gripping and retaining the core are carried by an annular member or ring 66 arranged in the bottom of the socket 65. The ring 66 isiheld in position by the lower end of the pin 64 threaded into the socket. The several fingers 60 project upwardly from the rings `61 and 66 and their upper ends may be bowed inwardly to effectively engage and carry the core. The other parts of the drill illustrated in Fig. 8 of the drawings may be similar to the corresponding parts illustrated in Figs. 1 to'7 inclusive of the drawings and described above.

The tool illustrated in Fig. 8 of the drawings operates in substantially e same manner as the embodiment of the invention first described. The

two sets of core catching spring fingers 60 are.

operable to effectively gripand support the core.

Having described only typical preferred forms of my invention, I do not wish to^limit myself to the specific details set forth, but wish to reserve to myself any changes or variations that may appear to those skilled in the art or fall within the scope of the following claims:

Having described my invention, I claim:

1. A well tool of the character described including, an outer barrel, a bit head detachably mount-v ed on the lower end of the barrel having cutting parts for making an annular cut in the formation, a core barrel in the outer barrel movable longitudinally relative to the outer barrel, an annular body. on the core barrel projecting downwardly below the lower end of the bit head, cutting blades on the body projecting downwardly below the said cutting parts and projecting outwardly between the said cutting parts, there being an annular fluid passage between the core barrel and body and the outer barrel discharging around the projecting end of the body, and a lug on the body cooperating with a vertically elongate .socket in the bit head to limit longitudinal movement of the core barrel and body in both directions.

2. A well tool of the character describedincluding, an outer barrel, cutting means on the lower end of the outer barrel to make an annular cut in the formation, a core barrel within the outer barrel, a tubular body on the lower end of the core barrel having cutting parts below the said cutting means, there being an annular fluid passage between the cutting means and the said body, and a connection between the outer barrel and core barrel whereby the core barrel is movable longitudinally relative to the outer barrel and is rotated with the outer barrel including an integral lug on the said body extending into an elongate socket in the said cutting means and adapted to engage the lower end wall of the socket to limit downward movement of the core barrel and body.

3. A well tool of thecharacter described includ-r ing, an outer barrel, cutting means on the lower end of the outer barrel to make an annular cut in the formation, a core'barrel within the outer lthe said cutting means, there being an annular fluid passage between the cutting means and the said body, and a connection between the outer barrel and core whereby the core barrel has limited longitudinal movement relative to the outer barrel and is rotated (with the outer barrel, said connection including lugs von the body co-operating with sockets in the said cutting means and adapted to engage the lower ends of the sockets to limit movement of the core barrel and body.

roamed 4. A well tool oi' the character described including, ari/outer barrel, a bit head on the lower end lof the outer barrel having spaced cutting blades to make an annular cut in the formation, a core barrel within the outer barrel, a tubular body on the lower end of the core barrel having cutting parts projecting below the said cutting blades and projecting outwardly between said blades, there being an annular fluid passage between the cutting means and the said body, core catching means in the core barrel, and a connection between the outer barrelvand core barrel whereby the core barrel has limited relative longitudinal movement relative to the outer barrel and is rotated with the outer barrel and is spaced from the 'outer barrel to provide said annular fluid passage, said connection including circumferentially spaced lugs on said body slidably cooperating with elongate sockets in the interior of the bit head. j

5. A well tool of the character describedfincluding, an outer barrel, cutting means on the lower end of the outer barrel, a core barrel within the outer barrel, a tubular body on the lower end of the core barrel having cutting parts, a connection between the outer barrel andthe core barrel whereby the core barrel is rotated with the outer barrel and is movable longitudinally relative to the outer barrel, said connection including a lug portion on the said body slidably cooperating with a groove in the outer barrel,v and a dog pivotally mounted in a socket in the said lug portion operable to cut a core upon rotation of the tool.

6. A well tool including an outer barrel, a bit head on the lower end of the outerbarrel operable to make an annular cut in the formation, an inner barrel within the outer barrel, a tubular body on ymounted in the recesses.

the outer barrel to provide an annular uid passage around the inner barrel and said body, there being sockets in theinterior of said body in the lug portions, and core engaging dogs pivotally mounted in the last mentioned sockets.A

L well tool includingan outer barrel, a bit head on the lower end of the outer barrel operable to make an annular cut in the formation, an inner barrel within the outer barrel, a tubular body on the lower end of the inner barrel having cutting partsprojecting below the bit head, lug portions on the said body cooperating with vertically elongate sockets in the bit head to connect the inner barrel with the outer barrel for limited longitudinal movement relative .to the outer barrel ,and spacing the inner barrel and the said body from the outer barrel to provide an annular fluid passage around the inner barrel and said body, there being sockets in the interior of said ybody in the lug portions, core engaging dogs, and pins pivotally mounting the dogs in the last mentionedl 'barrel withinthe outer. barrel, a tubular bodydetachably connected with the lower end of the inner barrel and having cutting parts projecting below the bit head, lugportions on said body cooperating with vertically elongate sockets in the bit head to connect theinner barrel and the body with the outer barrel for limited longitudinal movement relative to the outer barrel and spacing the inner barrel and said body from the outer barrel to provide an annular fluidpassage around the inner barrel and said body, and operable to prevent loss of the said' body in the event that it becomes disconnected from the inner barrel, there being recesses in the interior of the said body in the lug portions, and core engagingr dogs pivotally