US2613916A

US2613916A - Sampling sub with removable cutting collector

Info

Publication number: US2613916A
Application number: US193189A
Authority: US
Inventors: James N Gregory
Original assignee: Shell Development Co
Current assignee: Shell Development Co
Priority date: 1950-10-31
Filing date: 1950-10-31
Publication date: 1952-10-14
Anticipated expiration: 1969-10-14

Description

Uct. 14, 1952 J. N. GREGORY 2,613,916

SAMPLING SUB WITH REMOVABLE CUTTING COLLECTOR Filed Oct. 31, 1950 O 2 SHEETS-SHEET l FIG. 6

lnven+0r= Jo mes N Gregor BLT MW Oct. 14, 1952 J. N. GREGORY SAMPLING SUB WITH REMOVABLE CUTTING COLLECTOR 2 SHEETSSHEET 2 Filed Oct. 31 1950 FIG. 8

FIG]

James N. Gregory \nver'd'or:

His Afiornem,

Patented Oct. 14, 1952 SAMPLING SUB WITH REMOVABLE "CUTTING COLLECTOR .James .N. Gregory, Fullerton, .CalifQ, .assignor to zShell .Development Company, San Francisco, -Ca-lif,, azcorpor-ation of Delaware 'AppIication'October 31, 1950, Serial No. 193,189

The present invention relates to apparatus for drilling and coring or logging wells and pertains more particularly to apparatus for collecting :samples of iormation cuttings from -a stream of drilling fluid at a point near a drill bit during rotary-drilling.

During well drilling operations, -a well may be logged by studying the earth cuttings as they return to the-top of the well in the circulating stream of drilling fiuid. Thefluid is either run through a screen upon which the cuttings are .collected,:or a sample of fluid -is periodically taken from the .drilling fiuid stream, ditch-or pit, and .the cuttings contained therein are later separated from the fluid in a laboratory. The main disadvantages of collecting samples of 'bit cuttings at the top of the well is that the'cuttings are gen- --erally *small in 'size and 'have been contaminated by being carried in the stream 'of drilling fluid for as long as an hour or more. Itis furthermore difficult to correlate the cuttings with the *par- 'ticular depths to which they belong.

"Thus, in order to obtain "relatively large, -un- "contaminated samples of the formation being traversed by a borehole, it is generally necessary 11 Claims. (Cl. 255-i1.'.4)

to resort to -bottomhole or side-wall coring.

These methods of "coring, while normally ade- -quate, result in considerable loss of "time in that drilling operations must be stopped while a core :is taken. "-tainedby conventional apparatus are "often inadequate *for *m'icrofaunal determination because microfauna specimens occur -instreaks which are oftenmissedby taking spot core samples.

Samp'ling 'devices for obtaining bit cuttings from the bottom of a borehole usually have the drawback of being fixedly secured 'to the lower portion of a drill string, necessitating theshut- -ting down 0f drilling operations and the raising [of the entire can string to the surface for the removal of the cuttings' from the=samp1ing device. -It is therefore a primary ob-ject of the present invention to provide apparatus for continuously obtaining samples dfrelattvely'large size 'bit cuttings from 'ithe circulating drilling fluid.

'It' is also an object-of this invention-'to -pro vide apparatus for continuously obtaining uncontaminated samples of earth -or "cuttings near the ibottom of 'a borehole directly after they :are iwashedaway from thedrillbit.

.Ano'ther:obj ect: of .this invention -is to provide n novel type of sampling sub :adapted to contain-a :sampling :device :for :continuously areceiving bit -r cuttings, said ssub being .:provided :with :conduit Additionally, -sidewall samples 'ob- .2 thereth-rough while sample cuttings :are being obtained.

-I hese and other objects .of this invention will be understood from the following description 10f the invention as shown in the accompanying drawing, wherein:

Figures ,1 to 4 are views, partly-in crosssection. of di'fierent embodiments of the present appa- -ratus, .comprising a'sampling device positioned in a specialrsubor section of a drill string.

Figure 5 'isa cross-sectional view taken along the line v5':5 :ofFigure ,1.

Figure 6 is a cross-sectional view taken along the line 6'6 of Figure 3.

Figure 7215 a viewinfront elevation cf'a closure sleeve or :plug adapted to be lowered into the special :sub :in place of a sampling device.

1Figure.8 is :an isometric view of a removable liner-adapted to fit within the chamber of .a;:sampling-device.

Figure 9 is a view, taken in cross section, illustrating the present sampling device and :its :associated sub positioned in a drill string at :the :bottom of a well .borehole.

Referringto Figure 1 ofthe-drawing,vthe;present sampling apparatus comprises :an elongated tubular member i=0 having fixedly positioned :in its bore ill suitablecontainer :means such ;as ;a holder l2 .for positioning a sampling device :or cutting collector t3 therein. The tubular "member 1-0, otherwise known as asub orshortsection of :drill pipe or :drill collar, .is threadedzatzits upper :and

lower ends

14 and 15, respectively, :whereby theupper end :l ll maybe connected to .a'section of drill pipe or a drill collar I6, and the lower end 15 may be connected to another ,section 'of the drill pipe or to a bit H. The specialf sub 10 :is preferably .zconnected into :the drill string l6 directly above a wall scraper or drill bit 1|:1, :as

shown in Figure 39, but it is understood that the present sub may be connected between .any two sections of theydrill string.

The tubular smember I0 is provided with :one or more slots'or ports I 8 through the wall l9 thereof to permit earth. cuttings .to enter .the bore :11. Preferably, the axis 'of the slot l8 slants downwardly-to :permit any cuttings :entering :the .SlOt l8 to slide-into "the bore 1 I. Howeven-the ".walls .of the 'slot may have any other slant :(or may extend horizontally, .as shown :in Figure '19-) Preferably, the slot [8 is located near :the upper zend ofthe sub 5E0 and-may be :of any size desired. However, 'the' slot opening shouldihave :an area :of :several times :the size of the cuttings which iit Iimam for permitting 1131 8 ;jfl .;of .drilling zflui'diifib is .idesired-rto- 'collec't. :If :desired, ,an annularrecess 20, having a width at least equal to the length of the slot I8, may be cut in the outerwall of the tubular member II! at the level of the port or ports I8. The purpose of this annular groove or recess 20 will be explained hereinafter.

The axial bore II of the sub I is normally of the'same diameter as the bore of the drill string I6. The holder I2, which may be formed of a tubular member open at its upper end 2| and preferably closed at its lower end 22, is fixedly supported in a preferably coaxialmanner in the bore I I of the sub II] by

support members

23 and 24, seen in Figure 1, or 25 and 26, seen in Figure 5. The holder I2 is provided near its upper end with a longitudinal slot or Window 2! through the wall thereof, said slot 21 being preferably equal in size to the slot I8 in the sub 16, to permit earth cuttings to pass readily therethrough and into a container I3 carried within the holder [2. The supports 23,

' 24, 25 and 26, which may be Welded to both the inner wall of the sub I6 and the outer wall of the holder I2, form a short conduit or fluidtight passage for conducting samples entering the slot I8 in the sub across the annular space between the sub I0 and the holder I2 and through the slot 21 therein. If desired, the supports 23 to 26 and the edges of the slot 21 in the holder I2 may be slanted at substantially the same angle as the walls of slot [6 to facilitate the entrance ofcuttings into the collector I3.

Preferably, a small port 29 is drilled in the wall of the sub II] at a level below the lower end of the holder I2. A similar port 36 is provided in the lower end of the holder I2 and a short section of conduit 3| is inserted through said

ports

29 and 36 and welded therein so that the bore 32 of the holder is in communication with the space outside of the sub Ill. The conduit 3I is preferably slanted to permit cuttings or debris, which may enter the scabbard I2 when the collector I3 is removed, to drain therefrom.

The sampling device or cutting collector I3 comprises an elongated tubular member closed .at both ends to form a chamber 39, the lower end thereof being closed preferably by a removable pointed cap 33. The removable cap 33 facilitates the removal of cuttings from the collector and its pointed shape serves as centering or guide means when'the collector I3 is dropped into the holder I2. The upper end of the collector I3 is provided with an enlarged shoulder 34 which is adapted to be seated on the upper edge 35 of the tubular holder I2, as shown in Figure 1, thus supporting the collector within the holder. The collector I3 is provided with one .or more windows 36, 3'! and 38 which are of such dimensions and are so disposed in the wall of the collector that at least one of them is always in register with the slot 2'! inholder I2, whereby earth cuttings may pass through said slot and windows into the chamber 39.

In order to secure a more fluidtight seal between the cutting collector I3 and the inner wall of the holder I2, one or more annular grooves may be cut or formed in the outer surface of the collector I3 to accommodate rings 40 of any suitable packing material. Generally, however, an adequate seal is provided at the point where the shoulder 34 contacts the beveled seat 35.

The top III of the cutting collector is provided with an upwardly-extending axial rod 42 on which is mounted a centralizer of any desired type. As illustrated here, the centralizer comprises a pair of

stop rings

43 and 44 fixedly secured to the rod 42, a pair of

collars

45 and 46 slidably mounted on said rod 42 outside of said stop rings and a plurality of leaf springs 4! and 48 tending to expand and thereby maintained in sliding contact with the inner wall of the drill string IS. The upper end of the rod 42 is provided with a fishing neck 49 for removing the cutting collector I3 from the scabbard I2 and drill string I6.

In another embodiment of the present invention (Figure 2), a sub 56 having a sampling window 5I through the wall thereof is provided with a holder 52 eccentrically and slantingly mounted within the bore 53 of said sub 50. The holder 52 is also provided with a window 54 in the wall thereof which is in register with the Window 5| of the sub 56 when the holder 52 is affixed, as by welding, to the inner wall of the sub 50. The lower end 55 of the holder 52 is closed to form support means for a sample collector 56 adapted to be contained within the holder. A drain port 5! is drilled in one side of the holder 52 near the bottom thereof so as to register with a drain port 56 in the wall of the sub 56. The lower end of the holder 52 is preferably welded to the sub 56 at the drain port 58.

In order fora cutting collector 56 to enter the holder 52 when said collector is dropped down through the drill string I6, it is essential that the holder be of sufficient diameter, or be so positioned in the bore of the sub 56, that at least a portion of the open upper end 59 of the holder intercepts the axis of the subbore 53. Thus, with the collector 56 provided with a pointed cap 60 on its lower end and centralizer springs 6| and 62 near its upper end, the collector will be guided into the open end 59 of the holder and will drop into position in the holder as illustrated in Figure 2. Preferably, the bore 53 of the sub 56 is enlarged below the Window 5| in the sub, as shown at 63, whereby the holder 52 may be fixedly secured to the inner wall of the sub 56 in a tilted position which positions the upper end of the holder substantially in the center of the sub.

Threadedly secured to the top of the collector 56 is a rod member 64 carrying the centralizer springs BI and 62 which may be designed to fit within the holder 52, and rings 65 of suitable packing material for forming a fluidtight seal between the collector 56 and the holder 52. While it is not essential that the collector and the holder be in fluidtight engagement, sealing means are preferably employed to prevent any of the drilling fluid flowing down the pipe string l6 from entering the space between the collector 56 and the holder 52 and thus possibly disturbing the flow of cuttings entering windows 5i and 54. The top of the rod member 64 is also provided with a fishing neck 66 similar to the one in the embodiment of Figure 1. l a

In the embodiment illustratedin Figures 3 and 6, a sub 10 is provided with a pair of diametrically positioned windows or slots II and 12 through the wall thereof. A holder I3 is axially mounted in the bore I4 of the sub In, said bore I4 being enlarged over the portion of the sub adjacent the holder 13 to providean enlarged annular flow passage for fluid as it flows by the holder. The tubular holder I3 is provided with a pair of diametrically opposing

slots

15 and 16 which communicate with the windows II and 12 in the sub 1.6 by a pair of slanting flowout the slots I5 and I6.

TI and I9 are positioned between and engage I plates8I and 83, while supportplates I8 and 80

enga e plates

82 and 84. The members 11 to 84 are welded to the inside wall of the sub I and the outside wall of the holder 13 to form. 1

support means for positioning theholder in the center of the sub.v

The .holder I3 is open at both ends, the upper end 85sbeing beveled to seat the shoulder. 86 of a cutting collector 81 while the lowerend 88 is open to allow any material collecting therein to. be discharged therefrom. When employing a. holder I3 having its lower end open, itmay be. found .desirable to equip the collector 81 with packing rings 89 below its sample receiving slots 90.and 9I' as well as packing rings .92 above said slots thereby preventing any flow of fluid up the holder and out .its windows I and I6.

In; another embodiment of. the present invention, shown in Figure 4, a sub I00, having a single window IOI through the wall thereof, may containa holder I02 having one window I03 and adapted to receive a. cutting collector I04. The Scabbard I02 may be welded to spacer blocks I05, I06 and N1 which are in. turnwelde'dto the inner surface of. the sub I00.

When a cutting collector I04 is provided with a single window I08, it: is necessary to provide.

projects horizontally a short distance into the bore II thereof. As the collector I04 is lowered into thesubbody I00, the projecting pin II2 will rideuup the shoulder H0 and cause the col- 1ecto'r'I04 to rotate invthe bore of the sub I00 until: the-pin I12 and slot I09 are. in vertical alignment. In this position thewindows IN and I08 in the sub.I00 and collector? I04, respectively, are: in. register. 3

During drilling operations when no sampling off cuttings is desired, a cutting collector, such for example, as 81 (Fig. 3), may be removed and replaced with a suitable'plug or closure means for closing the slots I5 and 18 inthe holder whereby a drilling fluid being circulated down the'drillstring I6 will not by-pass the bit and As shown in Figure 7, one embodiment of a slot closure means may comprise a tubular member or closure sleeve H5 which'is equipped with a seating shoulder II-S near the upper end thereof which is adapted to engage the shoulder 85 at the top of the holder I3. The length of the tubular member 5' is such that the bottom of said member extends below the slots I5 and 1B, effectively closing them. The upper end of theclosure sleeve,

30 in the cutting collector I3, maybe, closed bya removable plug 33 which is secured ineany suit.-

able manner, as in screw-threaded engagement,-

tofthe bottom-of the collector I3. Ely-removing theplug 33, the collected-cuttings may-be readily removed from the chamber 39. If; desired, the collector may be equipped with a removable liner I20 (Figure 8), having an open top and a closed lower end; The linerjis formed of a thin material shaped. to fit within the annular chamber 39. Whilea thinmetallic liner I20 may be used,

' it=is preferably made of a transparent. plastic cuttings in the'liner I will be arranged in. the

'lector '13, by a inverse order in which the strata are penetrated. The cutting collector is :loweredbyc'able .or

dropped through the drill string i 6. and, into position-in the sub I0, as shownsin Figure a If: acable I2'3 is employed to .lower the'co-ll'ector, the cable is withdrawn tothe surface before drillingoperations are resumed. Drilling fluid being circulated-down the drill string; Ifiepasses through-the annular space II around theholder I2, through the bit I1, and up the annular 'pase sageway-I2'4 between the drill t6 and. the

wall or theborehole. ,1

The present cutting collector operates on the "principle that the velocity of .thetcirculating fluid rising in the annular passageway. I'21I..is reduced wh'enfthe fluid passes the slot; I8 and window 21- in the sub-I0 and the sample collector, respectively; An annular. recess 2 0'. v(Figure 1) in the outer wall of the sub 1 01 also acts to reduce thevelocity-ofthe-fiuid flow," The. re.-'

sulting decrease in the circulating. fluid velo'city' together withthe turbulence created by the slots reducesthe carrying power ofthe circulating fluid; The earth cuttings, especially thesl'arger and more desirable ones, are thrown Jouto'fethe mud stream and into 'the chamberr39- of: the collector I3. Thecollected cuttings may beiraised tothe surface of -the well along with the colfishing tool I22 at thetendofra cable I23.

I claim as -my invention:

1. Apparatus for collecting earth cuttings; from mudflush circulating in a borehole, comprising in combination a. tubular: member adapted to be connected into a drill string, a tubularholder fixedly carried within the: bore vofi said tubular member co-longitudi'nally therewith, the: outer -"diamet'eri ofsaid holder being appreciably smaller walls of said tubular member and said tubular holder adapted to register with said window means when said collector is insertedin. said holder, and fishing head means affixed' to the upper part of said collector for raising said? collector -fromsaid holder.

thereto by a. plurality of spaced lugs II8. Suit-- able centralizing springs I2I are also secured to-theupper end of the sleeve II5.

It 'is' realized that various changes and modiflcations may be made in the elements described herein without departing from the principles of this-inventioni As described with regard to the embodimentillustrated in Figure 1, the chamber 2. Apparatus for collecting earth cuttings from mudflush circulating in a borehole, comprising in combination a tubular member adapted to be connected into a drill string, a tubular holder open at. its upper end and closed at'its lower end positioned within the bore of said tubular member coaxially therewith, the outer diameter of 'said'holder being appreciably smaller than the innerdiameter of said bore, whereby an annular fluid passage is formed'within said bor'e about said holder, spider means in said passage fixedly attaching said holder to said member, conduit means through' the-wall of said tubularmemher and through the wall of said tubular holder near the lower end thereof,.a hollow cylindrical sample collector slidably fitting within theholder, radial windows through the: walls of said;:.col- 'lector near the upper end thereof, "ported radial conduit meansithrough'the walls. dfzsaid tubular member and said tubular holder adapted. to register with said windows when said. collector is inserted in said holder, and fishing head means afiixed .to the upper part of said collector for raising said collectorfrom saidholder. 1

3. Apparatus for collecting earth cuttings. from mudflush, circulating in :a borehole, comprising in combination a tubular-member adapted to be connected into a drill string, atubular holder fixedly carried eccentrically within the bore of said tubular member co-longitudinally therewith,

the axis of the bore of said tubularmemberbeing arranged at an angle, inclined ,to -.the axis ofcthe bore of said tubular; holder, the outer I diameter of said holder. being considerably smaller than the inner diameter,.ofsaidcbore, whereby a fluid passage is formed within said I bore outside said holder, a hollow cylindrical sample collector slidably fitting within the holder,

. radial window means throu h the walls of said collector, a ported radial conduitthrough the walls of said tubular, member and said tubular,

holder adapted to register with said window means when said collector is" insertedinsaid holder, and fishing head means 'afiiXed to the upper part of said collector for-raising said'collector from said holder. 1 a h 1 4. Apparatus for collecting earth ,cuttingsfrorn mudflush circulating in a borehole, comprising in combination a tubular member adapted :to be connected into a drill string, a tubularholder fixedly carried eccentricallyand slantingly within the bore of said tubular member,- substantially co-longitudinally therewith in a manner suchthat the axis of the bore of said tubular member passes within the periphery of .the upper open endof the bore of saidho-lder, said holder being closed at the lower end thereof, the outer diameter of said holder being appreciably smaller than the inner diameter of said bore, whereby a fluid passage is formed within said bore outside said holder, a hollow cylindrical sample collector slidably fitting within-the holder, said collector having a tapered lower end for guiding said collector into said holder, radial win- .dow means through the walls of said collector,

a ported radial conduit through the walls of said tubular member and said tubular holder adapted to register with said window means-when said collector is inserted in said holder; a ported drain conduit extending outwardly through the wall of said tubular member and inwardly through the wall of said holder in communication with the closed lower endthereof, and fishing head means afiixed to the upper part ofsaid collector for raising said collector from said holder. 7 w I 1 5, Apparatus for. collectingearth cuttings from mudfiush circulating'in a borehole, comprising in combination a tubularmember adapted to be connected into a drill string, a tubular holder having an open upper end fixedlycarried within the bore of said'tubular member co -longitudinally therewith, thev outer diameter of saidholder window when said collector is inserted :in .saidholder, fishing head means affixed to the upper part of said collector for raising said collector from said holder, "and registering first and second guide-*means respectively carried by-said holder and said collector, whereby the engagement of said first and-second guide meansupon the downward sliding of said collector within the bore of saidtubular holder moves said collector to a position wherein the'window thereof registers with thelported conduit through said tubular member and holder. l 1- 6. Apparatus for collecting earth cuttingsfrom mudfiush circulating in a borehole,comprising in combination a tubular member'adapted to be connected into a drill string, a tubularholder fixedly carried within the bore of said tubular member co-longitudinallyv therewith, the outer diameter of said :h'older being 'lc'ons'iderably smaller than the inner,..diam'eter of said'bore, whereby a fluidpassage-is formedunwithini said bore about said holder, a hollow cylindricalisample collector slidably fitting within the holder,

a' radial window through the walls of 'said'collector, a ported radial conduit through the walls of said tubular member and said tubular holder adaptedto register with said:window whensaid collector is inserted in said holdenifishing head means affixed to the upper part'of said collector forraising said collector from said holder? and registering pin and guide means, one ofsaid means carried by said'collector and the other by saidholder, whereby the engagement :of said guide means with said pin means 'upon theentry ofsaid collector intolthe bore ofwthe tubular holder causes said collector to rotate until the window thereof is in register withusaid' ported radial conduit through the tubular'member. and holder as the collector i'sloweredlinto the holder.

7. Apparatus for collecting earth cuttings from mudfiush circulating in a boreholaycomprising in combination a tubular member adapted to be connecteduinto a drill string, a tubular holder fixedly carried within the. bore of, said tubular member co-longitudinally therewith, the outer diameter of said; holder being considerably smaller than the inner diameter of said bore, whereby, a fluid passage is formedwithin-said bore about said holder, a'hollow cylindrical sam ple collector slidably fitting within the holder, radial window means through the walls of said cllector, ported radialconduit means through the walls of said tubular member and said tubular holder adapted to register with said window means when said collector is inserted in said holdenthe outer wall of; said tubular member having an armular recess formed therein at the level of the ported'radial conduit means, and fishing head means afiixed to the upper part of said collector, for raising said collector from said holder. I I w 8. Apparatus for collecting earth cuttings from mudflush circulating in a borehole, comprising open upper end, spider means fixedly supporting said holder member within said enlarged bore portion, an annular fluid passage being formed within said enlarged bore portion about said holder, a hollow cylindrical sample collector slidably fitting into the holder, radial windows through the walls of said collector, ported radial conduit means through the walls of said tubular member and said tubular holder adapted to register with said Windows when said collector is inserted in said holder, and fishing neck means affixed to the upper part of said collector for raising said collector from said holder.

9. Apparatus for collecting earth cuttings from mudfiush circulating in a borehole, comprising in combination a tubular member adapted to be connected into a drill string, tubular holder means fixedly positioned within the bore of the tubular member, said holder means being open at the upper end and having an outside diameter substantially smaller than that of the bore of said tubular member, whereby a flow passage is formed between the outer wall of said holder means and the wall of said bore, drain means in the lower end of said holder means, conduit means through the walls of said tubular member and said holder means inv communication between the bore of said holder means and the space outside said tubular means, an elongated hollow cylindrical sample collector fitting slidably within the holder means for insertion and removal through the upper open end thereof, an axially-elongated chamber in said sample collector closed to the space within said drill string, radial window means opening to said chamber through the walls of said sample collector, said window means being adapted to register with the conduit means of said tubular member and holder means when said sample collector is placed therein, and centralizer means carried by said sample collector for centering said sample collector as it passes downwardly through the drill string,

10. Apparatus for collecting earth cuttings from mudfiush circulating in a borehole, comprising in combination a tubular member adapted to be connected into a drill string, a tubular hold-' er fixedly positioned within the bore of the tubular member, said holder being open at its upper end and having an outside diameter appreciably smaller than the bore of said tubular member whereby a flow passage is formed between the outer wall of said holder and the wall of said bore, drain means in the lower end of said holder, conduit means through the walls of said tubular member and said holder, an elongated hollow cylindrical sample collector fitting slidably within the holder for insertion and removal through the upper open end thereof, said collector having a tapered lower end, shoulder means formed on the outer wall of said collector near the upper end thereof arranged to seat on the upper end of said holder, an axially-elongated chamber in said sample collector closed to the space within said drill string, radial window means opening to said chamber through the walls of said sample collector, said window means being adapted toregister with the conduit means of said tubular member and container means when said sample collector is supported therein, and centralizer means carried by said samplecollector for centering said sample collector as it passes downwardly through the drill string.

11. Apparatus for collecting earth cuttings from mudfiush circulating in a borehole, comprising in combination a tubular member adapted to be connected into a drill string, a tubularholder fixedly positioned within the bore of the tubular member, said holder being open at its upper end and having an outside diameter substantially smaller than the bore of said tubular member whereby a flow passage is formed between the outer wall of said holder and the inner wall of said member, drain means in the lower end of said holder, conduit means through the walls of said tubular member and said holder, an elongated hollow cylindrical sample collector fitting slidably within the holder for upward removal therefrom, said collector having a removable tapered lower end, shoulder means ,formed on the outer wall of said collector arranged to contact the upper end of said holder'for supporting the collector therein, an axially-elongated'chamber in said sample collector closed to the space within said drill string, radial window means opening to said chamber through the walls of said sample collector, said window means being adapted to register with the conduit means of said tubular member and container means when said sample collector is supported therein, a removable open-top liner carried within said chamber below said window means, and centralizer means carried by said sample collector for coaxially centering said sample collector as it passes downwardly through the drill string.

JAMES N. GREGORY.

REFERENCES CITED UNITED STATES PATENTS Name Date Sewell Oct. 19, 1943 Number