US2574717A

US2574717A - Coring apparatus

Info

Publication number: US2574717A
Application number: US64924A
Authority: US
Inventors: John C Stokes
Original assignee: Reed Roller Bit Co
Current assignee: Reed Roller Bit Co
Priority date: 1948-12-13
Filing date: 1948-12-13
Publication date: 1951-11-13
Anticipated expiration: 1968-11-13

Description

J. C. STOKES CORI Nov. 13, 1951 MG APPARATUS Filed Dec.

ATTORNEYS Patented Nov. 13, 1951 comivc APPARATUS .John C. Stokes, Houston, Tex., assignor to Reed Roller Bit Company, Houston, Tex., a corpora tion of Texas Application December13, 1948, Serial No. 64,924

Claims. 1

This invention relates to new and useful improvements in coring apparatus and more particularly to improved means for mounting the inner core-receiving barrel of such apparatus.

In the conventional core-taking apparatus of the type wherein an inner core-receiving barrel is carried within an outer barrel and is run into the well bore with the drill stem, it is customary to mount the inner core-receiving barrel so that it is freely rotatable within the outer barrel during the coring operations. It is, of course, desir-, able that the core barrel be mounted in a bearing assembly which will not only permit free rotation but which will also take the longitudinal or end thrust to which the inner core barrel may be subjected. Various methods and means of mounting the inner core barrels are in general use but in all such arrangements in which the bearings function as upper and lower end thrust bearings, it has been necessary to locate the bearing assembly at the upper end of the core barrel at a spaced distance from the core bit. Because of this loca-, tion of the bearing assembly, the core barrel must be removed from the upper end of the apparatus, thereby requiring that the connection betweenv the apparatus and the drill pine be broken. Further, with the bearing assembly at the upper end: of the inner core barrel, the core barrel must be fitted with relatively close tolerances between the said bearing assembly and the core bit at the lower end of the apparatus, thereby complicating the structure and increasing the expense of manufacture.

It is, therefore, one object of this invention to provide an improved mounting for the inner core barrel of a core-taking apparatus wherein the supporting bearing assembly is disposed nearer the lower end of the core barrel, whereby the necessity for the close manufacturing tolerances heretofore required is eliminated and also whereby the core barrel may be readily removed from the apparatus by merely removing the core drill and without having to break the upper connec-v tion.

An important object of the invention i to provide an improved mounting for the inner corereceiving barrel of a core-taking apparatus which mounting includes a double set of ball bearings located at the lower portion of the barrel for rotatably supporting the barrel and for taking longitudinal end thrust, the upper end of said barrel being aligned by a simple aligning bearing mem-.

an improved apparatus, of the character described, wherein the double ball bearing assembly on which the core barrel is rotatably supported is confined within a bearing housing, with said housing being disposed within the lower portion of the core-taking apparatus adjacent the core bit, whereby disconnection of the bit allows the, core barrel to be readily removed from the outer barrel of said apparatus.

Still another object of the invention is to provide an improved bearing assembly for mounting an inner core-barrel within the outer barrel of a.

core-taking apparatus, said assembly including upper and lower ball bearings and having suitable packing means for sealing off at the ends of the bearing assembly, together with simplified means for mounting said assembly against upward and downward displacement within the apparatus.

Other objects and advantages more or less ancillary to the foregoing and the manner in which all the various objects are attained will appear in the following description, which considered in connection with the accompanying drawings, sets forth the preferred embodiment of the invention.

In the drawings: v 1

Figure 1 is a longitudinal sectional View of a core-taking apparatus, constructed in accordance with the invention,

Figure 2 is an enlarged longitudinal sectional view of the lower portion of the apparatus and showing the improved mounting for the innercore barrel, and V Figure 3 is a horizontal cross-sectional view taken on the line 33 of Figure 2.

In the drawings, the numeral l0 designates the lower portion of a drill pipe which has a sub ll connected to its lower end. The core-taking apparatus is connected to the .drill pipe through the.

the sub. The lower end of the barrel I2 is con-- nected within the upper end of a drill collar l3,

and this connection is also illustrated as a weld,. although if desired it may be threaded. The.

lower end of the drill collar I3 is formed with the usual threaded pin l4, whereby a core bit l5 may be connected thereto. It will be evident that upon rotation of the drill pipe in, the outer barrel l2, drill collar [3 and core bit l5 will be rotated.

The core bit IEmay be of any desired construetion and, as shown in Fig. 2, has a central or.

axial bore l6 which bore is reduced at its lower portion, as indicated at l5a,'whereby an internal 3 shoulder I! is formed within the bit. Suitable cutters l8 are mounted on the lower portion of the bit and vertical fluid passages I9, which extend through the body of said bit, direct fluid onto said cutters during the coring operation. A core catcher 2B, which may be of ordinary construction, is supported upon the internal shoulder l1 within the: bore= of the. bit, and includes pivoted .fingers 2! which are normally urged inwardly into the bore. The body of the core catcher is generally sleeve-like and has its upper portion reduced, as indicated at 20a, whereby,

the exterior surface of the core catcher body is spaced from the bore [6 ofrthe: corabit. body I:

A suitable protector sleeve 22- -is,-.1nitially. suspended within the bore of the bit and is prevented from upward movementthrough the.bit. by means of projections 23 on its external surface. The body of the protector is :provided, with slits 24 and when a sufficient force is exerted against the lower end of. the. protector, the projections 23 -may. flex inwardly, thereby permitting the protector to'move upwardly within the bit. Downward movement of the protector 22 is prevented by the engagement of. the core catcher fingers 2|. with annular grooves or notches.25 formed in said. protector. The protector 22, aswell asthe core. catcher. 2!!- and the core bit l5, are all parts or usual construction,

and. the particular details thereof are subject to variation.

An inner core-receiving barrel. 26-extends axially within the outer barrel l2. and also within the drill collar l 3. and has its lower endterminatingadjacentthe upper. endof the core catcher 20. The upper. end of the. barrel is closed. by avalve cage21 whichis threaded. into this upper portion and. a suitable ball check valve 28. is mounted withinthe cage. The valve cage or body 2.1.is formed in two. pieces which are connected by a. threaded connection, and. an. annular alignment-bearing. 29. is mounted. within an annular groove. 30 formed. inthe upper end oithe valve. cage. or body 21.. .The alignmentbearing. may be constructed of neoprene or other. suitable material and has its outer peripheral surface formed with ribs or ,enlargementswhich are adapted to abut the bore l2a, of'the outer barrel l2. The alignment member 29 functions to axially align the upper end .of the inner barrel 26 within the outer barrel 12, while permitting a downward flow of fluid through the annularspace between said barrels. The valve cage. or body 21 has an axial .bore 21a which communicates with the area adjacent the valve seat 28a,

which is engaged .by the ball valve 28. A vent tube 32 threads into the bore 2.1a and extends upwardly therefrom.

It will be apparent that the ball valve 28 is downwardly closing and will prevent the admission of any fluid which may be flowing downwardly through the drill pipe into the core-receiving barrel 26. However, the pressure. within the core barrel 26 exceeds the pressure acting against theupper end of the ball valve 28, said valve may be unseated to permit a venting of the upper end of the barrel.

For rotatably supporting the lower portion of the inner barrel 26, .said inner barrel is provided with an external annular flange 33 which may be formed integral with said barrel. The flange 33 is located nearer the lowerportion of the barrel 26 and its upper surface provides an upper, bearing. raceway 34 while its lower surface forms a lower bearing raceway 35. Upper .32

rbetween the barrel 26 and the housing 38.

The lower portion of the bearing housing 38 telescopes and is suitably secured to the upper end of atubular, sleeve or casing 42. The upper endiof this'casing or sleeve has the lower bearings 31: supported: thereon, whereby this upper .edge, indicated at 4211, forms a raceway for the "lower ball" bearings 31.

The sleeve or casing 42 extends. downwardly and has its lower end insertable within the bore; l6 of the core bit. An external annular shoulder 43 which is. downwardly facing,v is formed on the lower portion. of. the sleeve or casing 42 and abuts an internal shoulder l5a provided within the core bit, the engagement of the external shoulder 43 with the internalshoulder l5a functioning to limit the downward movement of the sleeve or casing 42. For confining the bearingassembly against. upward. movement with respect to the core, bit and outer barrel, a plurality of spacing ribs, 4.4 are welded. or otherwise secured. to the intermediate portion. of the sleeveor casing .42. Each ribis. formed with an upwardly facing shoulder 45. at its lower end, and this shoulder. is adapted to abut the. Thus, it will.

lower end l3a of the drill collar I3. be seen that when the inner barrel 26 and, its lower bearing assembly are in position within the. outer barrel and vdrill3collar, said inner barrel and bearing assembly is confined against upward:

'bit. It is noted that the spacing ribs 44 also function to axially align the lower portion of the bearing assembly sleeve 42 within the drill collar, and thus, the lower end of the core-receiving barrel 26 is axially aligned with respect to the outer barrel I2.

In use, the apparatus is assembled as shown in Figure 1 with the inner core-receiving barrel 26 supported upon the double set of

ball bearings

36 and 31 at its lower portion. The upper end of the core-receiving barrel 26 is maintained in axial alignment within the outer barrel I2 by the annular alignment bearing member 23. As the coring operation is carried out by rotating the drill pipe, outer barrel I2 and core bit l5, the core which, is cut ,moves upwardly within the bore of the inner barrel 26. The inner barrel, being mounted on the upper and lower bearings 36 and31, may remain stationary, While the outer barrel and core bit rotate. The bearing assembly sleeve 42 has its lower end engaged within the bore of the core bitandthis sleeve will, rotate with the bit. As is clearly shown in Figure 2, the bearing assembly sleeve 42 and the confining bearing housing 38, which is attached to said sleeve, are rotated with thecore bit and outer barrel. The inner core-receiving barrel 26 remains stationary because of its engagement with the core, and free rotation of the bearing assembly housing and sleeve is possible because of the

double ball bearings

38 and 31. Any end thrust which might occur longitudinally of the inner barrel 26 is taken by the

bearings

36 and 31, upward thrusts being absorbed by the upper bearings 36 with the downward thrust being upon a the lower bearings 31.

After a core has been taken, it is only necessary to disconnect the core bit I from the drill collar l3. As the bit is removed, the lower portion of the bearing assembly sleeve 42 is disengaged from the bore l6 of said bit. The entire inner barrel 26, together with the lower bearing assembly, may then be removed through the lower end of the barrel l2 and its drill collar l3. Removal of the barrel 26 results in a removal of the check valve arrangement 28 as well as the vent tube 32 which are secured to the upper end of said inner barrel. Thus, it is possible to retrieve the core without having to break the connection between the drill pipe and the outer barrel l2 at the upper end of said outer barrel. Furthermore, since the main bearing support is at the lower end of the inner barrel 26 and the upper end of said barrel is maintained in axial alignment by a simple annular bearing element, close tolerances in arranging the bearings are not necessary. As illustrated, there may be a substantial distance between the upper end of the valve cage 27 and the lower end of the connecting sub II. In prior devices, where the double bearing assembly is located at the upper end, the lower end of the barrel must be supported within the core bit and the tolerances must be held fairly close. In the present arrangement, wide tolerances are allowed which simplify manufacturing and reduce costs.

The particular bearing assembly is extremely simple and provides not only for free rotation of the inner barrel with respect to the core bit and outer barrel, but also functions to take care of any longitudinal end thrust in any direction. The bearing housing 38 may be provided with a suitable fitting 41 which would permit lubricant to be directed to the

bearings

36 and 31. If desired, the supporting sleeve or casing 42' of the assembly may have a radial port or ports 48 extending through its wall, whereby the drilling fluid or mud which is circulated downwardly between the inner barrel 26 and the outer barrel I2 during the coring operation may enter the interior of the sleeve or casing 42 and function to lubricate the various parts. The bearing assembly and the lower end of the core-receiving barrel 26 are actually supported within the core bit [5 and upward displacement of the parts is prevented by the external shoulders '45 of the spacing ribs 44 which are secured to the exterior surface of the bearing assembly; This makes it possible to readily insert or remove the inner core-receiving barrel 26 by merely removing the core bit l5. J

Having described the invention, I claim:

1. In a coring apparatus, an outer barrel, a core bit threaded onto the lower end of said barrel, an inner core-receiving barrel extending axially within the barrel, and a bearing assembly supported within the core bit and including an elongate sleeve extending upwardly and encircling the lower portion of the inner barrel,

bearing means between the sleeve and inner barrel for rotatably suspending said inner barrel within the outer barrel, and means for sealing the space between the sleeve and barrel above the bearing means to protect the bearing means from contact with fluid circulating downwardly around the exterior of the inner barrel.

, 2; In a coring apparatus, an outer barrel, a core bit threaded onto the lower end of said barrel, an inner core-receiving barrel extending axially within the barrel, and a bearing assembly supported within the core bit and attached to the core-receiving barrel, said bearing assembly extending upwardly to encircle the lower portion of the inner barrel and having means for rotatably suspending said inner barrel within the outer barrel, means within the core bit engageable by the lower portion of the bearing assembly for supporting the assembly and inner barrel, whereby disconnection of the bit from the outer barrel disengages said bit from the lower portion of the assembly,and said assembly and the inner core barrel may be subsequently removed as a unit from the outer barrel through the lower end thereof.

3. A coring apparatus including, an outer tubular barrel, a core bit connected to the lower end of the barrel, an inner core-receiving barrel extending axially within the outer barrel and having an annular projection on its lower portion, a bearing assembly including a tubular member surrounding the lower portion of the inner barrel and also including upper and lower bearing elements within the bore of the tubular member engaging opposite sides of the annular projection, whereby the inner barrel is rotatably suspended on said bearing elements, and means at the lower end of the bearing assembly for engaging the core bit to support said assembly.

4. A coring apparatus including, an outer tubular barrel, a core bit connected to the lower end of the barrel, an inner core-receiving barrel extending axially within the outer barrel, an external annular projection on the lower portion of the inner barrel and having its upper and lower surfaces forming bearing raceways, bearing elements on said raceways, and a confining housing surrounding the inner barrel and confining said bearing elements on their respective raceways, means for mounting the housing against displacement from the inner barrel, and means for supporting the housing within the outer barrel, whereby the inner barrel is rotatably suspended within the outer barrel by means of said bearing elements and housing.

5. A coring apparatus including, an outer tubular barrel, a core bit connected to the lower end of the barrel, an inner core-receiving barrel extending axially within the outer barrel, an external annular projection on the lower portion of the inner barrel and having its upper and lower surfaces forming bearing raceways, bearing elements on said raceways, a confining housing surrounding the inner barrel and confining said bearing elements on their respective raceways, means for mounting the housing against displacement from the inner barrel, and means for supporting the housing within the outer barrel, whereby the inner barrel is rotatably suspended within the outer barrel by means of said bearing elements and housing, and an aligning means carried by the upper portion of the inner core-receiving barrel for maintaining the inner barrel in axial alignment within the outer barrel.

6. A coring apparatus as set forth in claim 2,

7 weat w th h a in Me n at he up r 29 tion of the inner core-receiving barrel for axially aligning said inner barrel Within the-outer barrel.

'7. A coring apparatusas set forth in claim 4, wherein the means for supporting the housing within the outer barrel comprises an internal shoulder within the core bit engageable by the lower end of the housing, and also wherein said housing is formed. with an external projection which engages the lower portion of the drill Stem for limiting upward displacement of saidhousing relative to the drill stem to thereby limit upward axial movement of the inner barrel relative to theouter barrel.

8. A coring apparatus as set forth in claim 4, together with a packin means interposed b e-v tween bearing housing and the inner core barrel for packing off between these parts above the bearing elements.

9. A coring apparatus as set forth in claim 4, wherein the supporting means for the bearing housing comprises an external shoulder at its lower portion which is adapted to engage and rest upon an internal shoulder in the core bit, where? by when the bit is disconnected from the outer barrel its external shoulder disengages the hearing housing and said housing and inner barrel may be removed as a unit from theouter barrel through thelower end of said outer barrel.

1 0 A coring apparatus includjng, a drill stem,

8; a core'bit connected to thelower end of theidrill stem, a core-receiving. :barrelmounted axially within the lower portion of the drill stem, a hear-.- ing assembly surrounding the lower portion of the core receiving barrel-for rotatably supporting the lower end. of the core barrel, means mounting the bearing assembly against displacement from the core-receiving barrel, means on the core bit engaging the lower bearing assembl to maintain JOHN C. STOKES.

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

UNITED STATES PATENTS Number Name Date 1,305,727 mith -.-4-.V---,.---:--V M 3i 1 345,23 B ow F b: 93

8 5 2 'S uermen f fe- Au 1932