US2658726A - Core taking apparatus - Google Patents

Description

Nov. 10, 1953 J. c. STOKES coma TAKING APPARATUS s sneets-sheet 1 Filed Nov. 8, 194 8 fl VVENTOR 4/0/70 C. Sto/ es 2 [law A r roe y: m

Nov. 10, 1953 J. c. STOKES coma TAKING APPARATUS Filed Nov. 8, 1948 JNVENTOR A T TORNf Y5 iww M A a ##Tf 4 v NOV. 10, 1953 J, c, s o s 2,658,726

CORE TAKING APPARATUS Patented Nov. 10, 1953 CORE TAKING APPARATUS John C. Stokes, Houston, Tex., assignor to Reed Roller Bit Company, Houston, Tex., a corporation of Texas Application November 8, 1948, Serial No. 58,829

11 Claims.

This invention relates in general to core taking apparatus and in particular to improved means for venting the upper end of a core-receiving barrel.

As is well known, the usual core-taking equipment includes a core bit carried by the lower end of an outer barrel which is attached to the drill pipe, and an inner core-receiving barrel which is adapted to receive the core as drilling progresses; The inner barrel is free floating or rotatable with respect to the outer barrel, whereby the outer barrel and core bit may rotate to cut the core While the inner core-receiving barrel remains stationary due to its contact or engagement with the formation or core which moves upwardly therein as the coring operation proceeds. The usual drilling fluid or mud is circulated downwardly through the drill pipe and outer barrel and then upwardly through the open hole for th purpose of washing out the cuttings and for controlling the formation pressures which are encountered and it is desirable, during the drillin operation, to prevent the drilling fluid or mud from washing down through the inner core-receiving barrel. For the purpose of closing the upper end of the inner barrel against th admission of the downwardly circulated drilling fluid and also for venting the core barrel when the core moves upwardly therein, a downwardly closing check valve is mounted in th upper end of the barrel.

When the check valve opens, the upper end of the core barrel may be vented either into the area outside thedrill pipe or into the interior of the drill pipe, the venting being dependent upon the particular well conditions. However, in the past, core taking apparatus has been manufactured as an inside vent or as an outside vent core barrel and once assembled, cannot be used except for the particular purpose, without disassembly and rearrangement.

In connection with the check valve, it is sometimes desirable that prior to the taking of the core but after the core drill has been lowered into the well bore, a washing operation be carried out, circulation being downwardly through the corereceiving barrel to thoroughly cleanse said barrel. In such instances, it is necessary that the check valve be capable of being positioned after the washing operation.

It is, therefore, one object of the present invention to provide a core barrel having an improved venting arrangement whereby the barrel may be selectively vented to either the inside or outside of the drill pipe and may be readily con- 2 verted from one to the other without the necessity of disassembling or uncoupling various parts or adding special subs or the like.

An important object of the invention is to provide an improved core-orienting apparatus which may be selectively employed either with an inside or an outside vent arrangement and which is constructed so that washing down through the core barrel may be accomplished prior to the core operations, after which the upper end of the core barrel may be closed against downward fiow of fluid therethrough to prevent the circulated drilling fluid from entering said barrel during subsequent core-taking operations.

A particular object of the invention is to provide improved core-taking apparatus, of the character described, wherein the check valve arrangement is such that washing down through the barrel may be accomplished, followed by positioning of the check valve which functions to permit venting of the core barrel while preventing downfiow through said barrel, said valve arrangement functioning efficiently regardless of the area, whether interiorly or exteriorly of the drill pipe, to which the core barrel is vented.

A further object of the invention is to provide an improved apparatus, of the character described, wherein the conversion of the apparatus from an inside to an outside venting, or vice-versa, is accomplished by the opening and closing of outlet ports, with said opening and closing being preferably carried out by the insertion and removal of threaded plug lements.

Other objects and advantages more or less ancillaryto the foregoing and the manner in which the various objects are attained, reside in the specific construction and aggroupment of the elements peculiar to this structure, as will become apparent from a more complete examination. of this specification, in the claims of which there are assembled certain specific combinations of parts and specific construction indicative of the scope and spirit of the invention.

Referring to the drawings, in which like symbols designate corresponding parts throughout the several views:

Figure 1 is a longitudinal sectional view of an improved core-taking apparatus, constructed in accordance with the invention, and illustrating the core barrel having an outside vent,

Figure 2 is an enlarged transverse sectional view of the upper portion of the apparatus shown in Figure 1,

Figure 3 is a view similar to Figure 2 and i1- lustrating the upper end of the core barrel vented to the interior of the drill pipe, rather than to by washing down is possible regardless of whether the apparatus is employed with the inside or the outside venting arrangement.

In the drawings, the numeral I'D designates the usual drill pipe or stem and the lower .endth'ereof has a special sub [I connected thereto. The outer barrel l2 of the core taking apparatus has its upper end encircling thelower portion of the sub H and is illustrated as welded tosaidsub; however, the'barrel may be connected by threads .or other means to the lower portion of the sub. The outer barrel 12 .has its lower end connected by welding or otherwise to the upper end of a drill collar 13 and the lower end f said vdrill collar is connected to the usual core drill M. The drill may be of any desired construction and is illustrated as having cutters at its lower portion with an axial bore 1-6 extending therethrough. .A score catcherofany desired construction, generally indicated at H, is mounted upon a suitable shoulder 18 .formed within the bore of the drill l4.

For the purpose :of protecting the .core catcher structure .I1,-a protector 1910f usual construction is insertable within the bore of the bit and comprises a generally sleeve-like member formed with longitudinal slits .20. External lugs .21 .tormed on the protector normally prevent said protector from moving upwardly .into the core barrel :until a predetermined .force is exerted against .the lower end thereof. Downward movement of the protector is prevented .by engage- I merit of the core catcher fingers Ila with suit- .able annular notches or grooves formed in the upper-exterior surface .of the protector. The par-- ticularconstruct-ion of the core drill, catcher and protector form no part of the present invention and are included merely for the purposes of illustration. These parts are, therefore, subject to variation An inner core receiving barrel 2 is mounted within the outer barrel l2 .andhas its lower .end terminating just above the core catcher .str-ucture .11. The core receiving barrel 22 is free floating or rotatable with respect to the outer barrel 1.2 and is mounted .on ball thrust bearings 2.3 and. The bearings 23 and .24 engage upper and lower raceways which are provided on the upper .and lower surfaces of anannularflange 25 which is formed integral with the core receiving barrel 22. The bearings are confined by a retaining collar 26 which is secured to the upper end of a supporting .sleeve .21. The lower portion of the sleeve 21 is engaged within the bore I6 of the core drill and this lower end is packed off or sealed by suitable packing rings 28. .Sealing between the retaining collar 2.6 and the external surface .of the inner barrel 22 is effected by a suitable packing ring 29. The supporting sleeve 2! is spaced from the inner bore of the drill collar 13 by spacing ribs 30 which are welded or otherwise suitably secured to the outer surface of said sleeve. Each rib is formed with an upwardly facing shoulder 3| at its lower portion which .is adapted to engage beneath the drill collar I3 so as to limit upward displacement of the sleeve 27 and the retaining collar 26 connected therewith. Obviously, the space between the inner core receiving barrel and its supporting bearing assembly and the inner bore of the outer barrel and drill collar provides an annular flow space through which the drilling fluid may be circulated. g

It will be apparent that a core whichenters the lower portion of the inner barrel 22 will function to maintain the inner barrel stationary. The outer barrel l2 and the core bit I4 may therefore rotate to cut the core, while the inner core receiving barrel remains stationary. The bearings 23 and 24 provide for free rotation of the core bit and 'its :connected parts with respect to the inner barrel .and also form upper and lower thrust bearings to take any longitudinal thrust imparted to the inner barrel.

The upper end of the inner core receiving barrel- .22 has a valve body 32 threaded thereon and this body has an annular valve seat 33 mounted ins-its .lower portion. The pore 33a. extends through the valve seat is in communication with the upper end of the interior of the barrel .22. A head element 34 has its lower end threadedinto the upper portion of the valve body and is .formed with an axial bore 35, the lower end of which communicates with an enlarged cavity 36 formed within the valve .body.32 .An annular alignment bearing 31, which may be constructed of neoprene orpthersuitablematerial, is confined within the recess 38 formed inwthe exterior surface .of the head element 34. The-annular bearing 13.! has its outer periphery .in.close proximity to the bore of the outer .barrellz and functions to hold the upper end .of the inner barrel in axial alignment within said outer barrel.

The vent tube 39 has its lovv'er .end threaded into the upper end of the bore .35 of the head member 34 and this tube extends upwardly into the bore 40 of a wear sleeve 4|, which sleeve is mounted within the axial bore 4.2 of the special sub H. The vent tubeihas an axial bore39a extending entirely therethrough and functions to establish .icommunica'tion between the valve body above the valve seat and the upper reduced portion 420. of the "bore 42 of the sub .11. Suitable annular packing rings '43 are .mounted on the upper portion of the vent tube 139. The reduced portion Ma of the bore of the sub is internally threaded and is adapted-to receive a plug 44. This plug is employed, as will be explained, when the inner core barrel is .to be vented to the outside of the .drill stem and is removed when the device is employed with .a vent to the interior of the stem. .Above the reduced portion 42a, the sub H has its bore enlarged a indicated at 52b. and above this portion, internal threads for connection with the drill pipe l0 are provided.

A plurality of vertical passages 45 extend through the sub I l and establish communication between the .drill stem and the area below the sub. Thus, .drilling fluid may be circulated .downwardly through the drill stem and then through the vertical passages 45 and through the annular space between the inner barrel 22 and the .outer barrel ['2 downwardly to the core drill Hi. This circulation of fluid will, of course, occur during the actual drilling or coring operation.

For establishing an outside vent so that the interior of the core receiving barrel 22 may be vented to the area outside the drill stem, thesub H is formed with a radially extending port 46. As is clearly shown in Figure 2, the port extends through the wall of the sub and establishes communication betweenthe reduced portion 42a of thebore of said sub and the exteriorthereof. The port 48 has its outer portion enlarged and threaded and is adapted, under certain conditions as will be explained, to receive a closure plug4l; When the port 46 is open, it will be evident that a vent from thebore 42a which is in communication with the upper end of the inner barrel l2 through the vent tube 39 and valve body 32 is provided.

A ball valve 48 is adapted to engage the seat 33 within the valve body 32, and this ball is a downwardly closing check valve. The ball valve 48, when in position on the seat 33, will prevent any downflow through the valve body and into the upper end of the inner barrel 22; however, when the pressure within the barrel 22 exceeds the pressure holding the valve closed, said valve may unseat topermit a venting of the upper end of the barrel 22;

In using the apparatus in coring operations, it is possible to selectively vent the upper end of the inner core receiving barrel 22 either to the interior of the drill pipe or stem ID or to the area exteriorly of said pipe or stem. If an inside or interior vent is desirable, the plug 41 is inserted within the radial venting port 46 to close this port and the plug 44 is removed from the bore 42a of the sub l l. The apparatus is then lowered into the well in the usual manner and the coring operation results in a core entering the core receiving barrel 22. During the coring operation, the usual drilling fluid or mud may be circulated downwardly through the drill pipe and through the vertical passages 45 in the sub and downwardly around the inner core receiving barrel 22 to the core drill. The pressure of this circulating fluid will also be acting through the vent tube 39 and against the ball valve 48 which, being downwardly closing, prevents the drilling fluid from entering the upper end of the core receiving barrel, As the core moves upwardly within the inner barrel and it becomes necessary to vent the upper end of said barrel, the pressure built up within the upper end of said barrel will unseat the valve 48 and will allow a venting upwardly through the vent tube and into the downwardly flowing mud stream. Thus, with the plug 41 in place and the plug 44 removed, an inside or interior venting is obtained.

If conditions require that the core barrel 22 be vented to the area exteriorly of the drill pipe,

' venting port 46. In such case, venting of the barrel will be upwardly through the vent tube and then outwardly through the vent port 48. The conversion from an inside to an outside venting arrangement is readily accomplished by merely removing plug 41 and inserting the plug 44.

In certain instances and under certain conditions, it may become desirable to wash downwardly through the inner barrel 22 after the apparatus has been lowered into the well but prior to the time that a coring operation has begun. In such event, it is desirable that the ball valve 48 be positioned after the washing operation is complete and a structure which will permit washing down through the barrel prior to the beginning of the coring operation and subsequent positioning of the check valve is illustrated in Figure 7. In this form, (Figure 7) of the invention, the bore 35 of the head member 34 which is connected in the upper end of the valve body 32 has its upper end enlarged and screw threaded, as indicated at 35a. A vent tube 50 is adapted to have its lower end connected within the threaded portion 35a of the bore 35, this tube being substituted for the smaller vent tube 39 shown in Figure 2. The bore 50a of the tube 50 has substantially the same diameter as the bore 35 and the diameter of these bores is larger than the diameter of the ball valve 48, whereby said ball valve may be freely dropped therethrough and into position on its seat 33. The upper end of the vent tube 50 is disposed within the Wear sleeve 4| which is within the bore 42 of the sub II and suitable packing rings 5| seal off between the tube and the sleeve.

In place of the plug 44 illustrated in Figure 2, a valve seat 52 is threaded into the reduced portion 42a of the bore 42 of the sub H, and a ball valve 53 is arranged to engage this seat. It is noted that the bore or opening 52a through said seat is of substantially the same size as the bore 52a of the vent tube 59, whereby the ball 48 which seats within the valve body 32 may be dropped downwardly through the upper valve seat 52. The

ball 53 is, of course, considerably larger than the lower ball 48.

In using the apparatus shown in Figure '7 as an inside vent, the plug 41 is threaded into the port 48 and the apparatus is lowered into position within the well bore. At this time, neither the ball 48 nor the ball 53 are in position. After the apparatus has been lowered into the well bore, a washing operation may be carried out downwardly through the inner barrel 22 to thoroughly clean said barrel. The smaller or lower ball 48 is then dropped downwardly through the upper valve seat 52, then through the vent tube 50 and bore 35 of the head member 34 and finally onto thelower seat 33.

As the coring operation is carried out and the core enters the core receiving barrel 22, the upper end of said barrel is closed to the downwardly circulating drilling fluid with the check valve 48 being closed. When the upper end of the barrel is vented, the valve 48 is unseated by the internal pressure within said barrel so that venting of the barrel to the interior of the drill pipe is possible. As was pointed out, the plug 41 closes the radial outlet port 46 at this time.

When the apparatus is to be used for venting to the outside of the drill pipe, the plug 47 is removed from the vent port 46 prior to the time that the apparatus is lowered into position. If a washing down operation is to be performed, the lower ball check 48 and the upper ball check 53 are not in position on their respective seats and. are not dropped downwardly within the drill pipe until after such washing has been accomplished. Prior to the start of the coring operation the smaller ball 48 is first dropped downwardly onto its seat 33 followed by positioning of the upper or larger ball 53 on its seat 52. Drilling is then carried out and as the core enters the interior of the barrel, the internal pressure in its upper end increases. When this pressure reaches a predetermined point, the lower ball 48 is unseated and immediately the escape is through the open vent port 43. The upper ball valve is, of course, held on its seat by the pressure of the downwardly circulated drilling fluid and 0bviously venting will occur through the open port 46 before the ball 53 is unseated. Thus, it becomes obvious that the apparatus in Figure 7 may be employed for either inside or outside venting and yet may permit a washing down through the core barrel prior to the start of the nori-ngaoperation. Only the removal or insertion of the plug-diliinto the vent port is necessary to convert the apparatus :from an interior to an exterior venting, :or vice-versa.

'The device is extremely simple in construction and permits conversion of the apparatus to the particular ventingrarrangement which is most suitable for the well conditions. In the firstiorm of the invention shown .in Figure '2, only replacement or in-sertionof one or the other plugs 4'4 and 4 is required to effect the conversion. :In the second form, theremoval or insertion ofa single plug makes the device adaptable tor venting either interi'orly or exteriorly of the drill pipe. It ispointed out that the tube 50 maybe employed place of the :tube 39 in Figure 2, in which case the lower ball 48 could be dropped into position when the apparatus in Figure 2 :is used as an inside vent arrangement. In other words, with the plug A l of Figure 2 removed and the ;plug 41 in position in the vent port '56, the ball valve 48 may be positioned by dropping said ball downwardly through the drill pipe after .a downward washing through the barrel22 is completed. Thus, a washing action may be per formed prior to the coring operation in the form shown in Figure 2, so long as an inside venting arrangement is desired. If an outside vent is to be employed and it is desired to perform a washing operation "before cor-ing, then the plug 44 is replaced by the upper valve seat 52 and ball valve 53. .If no downward washing through the core barrel .22 is necessary and it is desirable only to provide an apparatus which is convertible from either an inside to an outside venting arrangement, thenthe apparatus in Figure 2 will be satisfactory.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details (of the illustrated construction may be made within-the scope of the appended claims without departing from the spirit of the invention.

Having described the invention, vI claim:

1. The combination with a core-taking apparatus which includes a :drill pipe and core bit, :of an inner core-receiving barrel, meansfor establishing communication between the upper end of the barrel and the area exteriorly of the drill pipe, means for establishing communication between the upper end of the barrel and the interior of the "drill pipe, :a removable closure for each communication-establishing means whereby the barrel may be-selectively vented to the interior or exterior of said drill pipe, and a downwardly closing check valve located below the means for establishing communication between the upper end of the barrel and the area exteriorly of the drill pipe to permit venting of the barrel while preventing downflow therethrough.

2. The combination as set forth in claim 1, wherein the check valve may be positioned after the apparatus has been lowered into the well *bore.

In combination, a core bit, a drill stem, a core-receiving barrel within the drill stem having a passage extending from its upper end, a sub connected in the drill stem above the core barrel and having a bore which establishes com munication between the core barrel passage and the interior of the drill stem, said sub also having .a vent .port establishing communication between thepassage and the area exteriorly of the drill stem, removable closure means for the bore oi the :sub and for the vent port, whereby said bore and port may :be selectively openedand closed to selectively connect the vcore-rbarrel'lpas sage to either the interior of the drill stem or (to the area -exteriorl-y :of said stem, and azdownwardly closing check valve mounted within the core :barrel passagebe'low' the vent port :for permitting upflow :from :said barrel while preventing downflow therethroug-h.

4. The-combination set forth in claim 3.,wherein'the check valve may be introduced through the drill stem and bore of the sub into position within the passage.

5.. In-combination, :a core bit, a drill :stem.'=.a core-receiving barrel within the drill stem having a passage extending :f-rom'zits iupper'end, a sub connected in the drill stem above the core barrel and having a bore which establishes communication between the core barrel passage and the interior of the drill astem, said sub also having a vent port establishing communication between the passage and the area exteriorly of the drill stem,-a removableplug tor closing the vent port, and .a downwardly closing check valve within the passage below the vent port for allowing upfiow from the core barrel while preventing :downil'ow therethrough.

6. In combination, a core bit, a drill stem, 12. core -receiv-i-ng barrel within the drill :stem having a passage extending from its upper end, a sub connected in the drill stem above the "core barrel and having a bore which establishesicommunica tion between the core barrel passage and the interior of the drill :stern, said sub also drawing a vent port establishing comml'mication between the passage and the area exteriorly of the dull stem, .a downwardly :closi-ng check valve mounted within the 'core barrel passage for permitting upflow from said barrel while preventing downflow therethrough, and closure means .inthe upper end offithe :bore of the "sub for closing said bore and shutting off communication between the passage and the interior of the drill stem.

7. The combination as :set forth in claim 6, wherein the closure means for the .upper end of the [sub bore .is 'a removable plug threaded into said :bore.

#8. The combination as set forth in claim '6, wherein the closure means for the upper end :of the sub .bore is azdownwardly closing check valve disposed atthe upper end of said bore.

9. In combination, a core bit, a drill stem, a core-areceiving barrel withinthe drill stem'hav-i-ng a passage extending from its upper end, .a sub connected in the drill stem above the core barrel and having a bore which establishes communication "between the core barrel passage and the interior of the drill stem, said subalso having a vent port establishing communication between the passage and the area exteriorly of the drill stem, a valve seat in the core barrel passage, a ball check valveadapted to engage said seat and arranged-to 'close -.against downward flow while permitting upward now through the passage, :a valve 'seat removablymounted in the bore of-the sub, and'an upper .ballcheck adapted to engage the seat in the sub bore "to close against :downward flow, the ball valves being capable of introduction through the drill stem after thezappae ratns is located within the well bore.

.10. The combination as set *forth in claim F9, wherein the ball valve within the passage is of lesser diameter thanthe upper ball valve, whereby said lower valve may be dropped into operating position through the upper valve seat and bore of the sub.

9 10 l 11. A core-taking apparatus including, a drill References Cited in the file of this patent stem, a core bit, an inner core-receiving barrel, UNITED STATES PATENTS a vent tube extending from the upper end of the barrel, and means for selectively and inter- Number Name Date changeably establishing communication between 5 18500 stoPe June 1932 the outlet end of said tube and the area inte- 2'040889 Whmnen May 1936 riorly of the drill stem or the area exteriorly of 2126'684 Humason et a1 1938 said drill stem, and a downwardly closing check valve in the vent tube below the outlet end of the vent tube. 10

JOHN C STOKES.

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