US2594292A

US2594292A - Side wall sampler

Info

Publication number: US2594292A
Application number: US80058A
Authority: US
Inventors: Cornelius Paul Dean
Original assignee: Byron Jackson Co
Current assignee: Byron Jackson Co
Priority date: 1949-03-07
Filing date: 1949-03-07
Publication date: 1952-04-29
Anticipated expiration: 1969-04-29

Description

April 29, 1952 P. D. CORNELIUS SIDE WALL SAMPLER 6 Sheets-Sheet l Filed March '7, 1949 INVENTOR. 0m/L D. Coene-U05 af; .11. (Hmw wt TTQNEHS wf .1a.

April 29, 1952 P. D. CORNELIUS 2,594,292

SIDE WALL SAMPLER o g A 'G2 IN VEN TOR.

l paz/L D. Coe/w1 /US www@ April 29, 1952 P. D. coRNELxUs 2,594,292

SIDE WALL SAMPLER Filed March 7, 1949 6 Sheets-Sheet 5 April 29, 1952 P. D. CORNELIUS 2,594,292

SIDE WALL SAMPLER J'o @a 7%. 5.o

INVENToR. 10m/L Q Cagiva/US April 29, 1952 Filed March 7, 1949 P. D. CORNELIUS SIDE WALL SAMPLER 6 Sheets-Sheet 5 INVENTOR.

/qz/ D. Coe/VENUS BY yu/r P. D. CORNELIUS SIDE WALL. SAMPLER April 29, 1952 Filed March 7, 1949 JNVENTOR. QQUL D. Chef/E PatentedA Apr. 29, 1952 SIDE WALL SAMPLER Paul Dean Cornelius, Hollydale, Calif., assignor to Byron Jackson Co., Vernon, Calif., a. corporation of Delaware Application March 7, 1949, Serial No. 80,058

(Cl. Z55-1.4)

36 Claims.

This invention relates generally to well drilling apparatus and is particularly directed to improvements in coring or sampling devices for taking a formation sample from the side wall of a well bore.

In recent years there has been a trend ,in the art of drilling oil and gas wells toward completion of the drilling from the surface to the total depth without interruption, thereby avoiding expensive standby time previously required Iwhile cores or formation samples were obtained. After such drilling operation is completed and while the well bore yet contains drilling fluid, the entire length of the uncased bore is electrically logged in order to select the most promising strata for production of oil or gas. From the information produced by the electrical logging devices the operator may then utilize a side wall sampler for obtaining cores from the side Walls of the bore hole in the regions of the potentially productive formation. While this practice of drilling to the full depth before taking cores is efcient in that it involves a minimum amount of time at the least expense, it does require that a reliable sampling tool be available for extracting formation samples from the side wall of the well bore, which samples will be suitable for complete geological analysis. It is the primary object of the present invention to provide such a side wall sampling tool of novel and improved construction.

Side wall sampling devices heretofore used in field conditions are of three types:

(1) Punch types. These usually employ a corereceiving tube having one end pivotally secured to the lower end of a drill string and arranged to be projected without rotation into the side wall so as to punch or tear out a fragment thereof upon vertical movement of the drill string. A serious disadvantage of the punch type sampler is that it is limited to use with well formations which are comparatively soft. Another difficulty is that the samples obtained are usually so crushed and broken that a full geological analysis is diicult to obtain. Another. disadvantage with the punch (3) Rotary types. These have commonly employed a rotary core bit and sample-receiving tube which are rotated by the drill string. Ordinarily a nonrotary housing is releasably anchored within the well bore at the lower end of the drill string and serves as a guide for the rotary core bit. This type of sampler yields the best core for geological analysis and it is capable of operation in hard formations. A disadvantage of this type of sampler as heretofore employed is that the drill string must necessarily be rotated at a relatively slow rate in order to avoid excessive movement of the nonrotary housing at the lower end of the drill string. Considerable time is thus required to cut a sample from the side wall of the bore hole. Since the sample undergoing extraction is exposed to the drilling fluid it is subject to considerable contamination. Furthermore, side walls samplers of the rotary type have heretofore been constructed so that an accidental increase in pressure of the wall iiuid might result in sticking of the sample-taking tube in the formation. In such devices the tube sometimes becomes so tightly wedged in the formation that it cannot be removed by a wire line or by the drill pipe. Thus an expensive shing job may be re quired. Other types of rotary side wall samplers have been proposed and among these is a type embodying a rotary sampling tool driven by a prime mover positioned in the well as distinguished from rotation by the drill pipe. However, in this proposed construction the sampling tool is not retrievable Ywhile leaving the prime mover in the hole, and hence the drill string must be Withdrawn and reinserted section by section for each sample obtained. The limitations and disadvantages enumerated above are avoided by devices employing my present inventionwhich devices are capable of extracting relatively long samples suitable for complete geological analysis from hard or soft strata on the side wall of the well bore in a minimum amount of time. Accordingly, one of the principal objects of this invention is to provide a novel side wall sampling tool for Wells capable of extracting from formations a core in its natural undisturbed condition and of sufficient size for geological examination. A related object is to provide a novel tool of this type capable of extracting a formation sample which is laterally displaced a sufficient distance from the side wall of the well bore so as to be substantially uncontaminated by the drilling fluid contained within such wellbore.

Y More particularly itis an object of this inven tion to provide side wall sampling apparatus retrievable on a wire line through the'interior of the drill pipe and having a coring tool adapted to be rotated by power means at the lower end of the drill string.

Another object is to provide drilling apparatus for use in a bore hole and having a prime mover mounted in a housing carried on the pipe string, the prime mover being adapted to rotate a cutting tool'retrievable through the drill string.

Another object is to provide improved means for advancing and retracting the coring tool and sample-receiving tube.

Another object is to provide a novel form of signal means for indicating when the coring device has been advanced and fully retracted into the retrievable assembly.

Another object is to provide a novel form of sample tube which is particularly well adapted to transmit both torsion and axial forces to the coring bit.

VAnother object is to provide a side wall sampling device having a sealed mechanism actuated by pressure of drilling iluid, yet sealed from contact therewith.

A further object is to provide a valve device at the lower end of the sampling apparatus which'functions to maintain a back pressure of well fluid on the mechanism in order that the advancing and retracting means for the coring tool may function without danger of sticking while in its extended position.

Other and more detailed objects and advantages will appear hereinafter.

In the drawings:

Figure 1 is a longitudinal sectional view partly broken away showing a preferred embodiment of my invention, the central retrievable portion thereof being shown in elevation. This ligure is separated into three portions in order that the entire length may be shown in convenient size. It will be understood that Figure 1b shows that portion of the device between the lower end of Figure la. and the upper end of Figure 1c.

Figure 2 is a sectional view similar to Figure 1c showing the positioner device and the rotary coring tool in extended position.

Figure 3 is a longitudinal sectional elevation partly broken away and showing details of construction of the inner retrievable assembly. This figure is separated into three parts, 3a, 3b and 3c in the mannerV similar to that described in connection with Figure 1.

Figure 4 is an enlarged sectional elevationof a portion of the retrievable assembly shown in Figure 3b with internal parts moved to a different position'.

Figure 5 is a sectional view similar to Figure 4 but with the internal parts moved to a different position.

Figure 6 is a sectional view similar to Figures 3a and 3b showing the internal parts in position for signaling that the coring tool has completed its cycle and is in retracted position.

Figure 'Tis an exploded view of certain of the parts illustrated in Figure 3b.

Figure 8 is a longitudinal sectional View showing the core bit, core tube and sample tube assembly.

Figure 9 is a transverse sectional view taken substantially on the lines 9-9 as shown in Figure 8.

Figure l is a transverse sectionalview taken substantially on the lines I-I as shown in Figure2.

Figure 11 is a transverse sectionalv view taken substantially on the lines II-II as shown in Figure 3a.

Figure 12 is a transverse sectional view taken substantially on the lines I 2-I2 as shown in Figure 3b.

Figure 13 is a longitudinal sectional view showing a modification.

Figure 14 is a perspective View showing a crank and the use thereof in setting the internal mechanism of the retrievable assembly prior to use.

Referring to the drawings, the sectional string of pipe I extends into a well bore II and is connected toa sub I2 at its lower end. The sub in .turnfis' attached to the upper end of a body or 'housing I3 which encloses the side wall sampling device. The housing I3 may be composed of several sections I4, I5, I6, I1 and I8 threaded together end to end. A portion of the housing encloses a turbine unit generally designated I9. This turbine unit is driven by a flow of mud fluid and acts to rotatefa retrievable core barrel assembly 20. The lower end of the assembly 26 is provided with a core bit 2l which may be hydraulically projected laterally through a side window 2,2 in a housing section and into the formation adjacent the well bore. A core cut from theforination is then retracted with the bit ZI back into the interior of the housing. The assemblyv 20 including the core bit 2| and core may then be retracted as a unit on a wire line upwardly through the bore 23 of the pipe string I0. The core is extracted and the assembly 20 may be lowered into the hole on a wire line and additional cores taken without requiring that the housing-I3 be removed from the well hole.

Referring more particularly to the detailed constructionof a preferred embodiment of my invention, the retrievable assembly 2U is adapted to be received within the housing I3. A shoulder 'I on the assembly rests on -an annular abutment 8 provided on the rotary sleeve 9. The sleeve 9 is carried on the thrust'bearing 24 and constitutes the rotor of the turbine generally designated I9. This turbine I9 includes a plurality of stator rings 26 and a plurality of rotor rings 21 arranged in alternate relationship. The blades 28 on the stator rings 26 `are curved in one direction and the blades 29 on the rotor rings 2l are curved in the other direction, as clearly shown in Figure 1b. Each of the stator rings is provided with a lower internal thread l30 adapted to engage an upper external thread 3| on the adjacent stator ring. The support ring 32 for the bearing 24 is threaded tothe lowermost stator ring 26 and rests on the shoulder 33 provided at the upper end of the housing section I6. A collar 34 rests on the uppermost stator ring 26 and confines the outer rim of `a screen 35 against a shoulder 36 on the lower end Vof* the housing section I4. From this description it will be understood that the housingsection I5 encloses the turbine I9 and connes the stator rings 26 between shoulders on the housing sections I 4 and I6.

Means are 'provided for moving the housing I3 away from a central position within the well bore I I and for crowding it against the side wall of the wellv bore. As: shown in the drawings. this means includes the housing section I8 which comprises a cage for the positioner unit generally designated 37. A sliding head 38 is provided with a piston 39at its upper end and a flange 60 at its lower end which are adapted to slide within vthe `central axial bore 4I. One or more sealrngs 42 rnaybeprovided on the piston 39. A wedge cam 43 is pivotallysecured to the cage epesses I8 by means of the pivot bolt 44. The Wedge cam 43 is also pivotally connected to a crosshead member 45 having cylindrical ends 46 adapted to roll on parallel horizontal guides 41 provided on the sliding head 38. The arrangement of parts is such that downward movementl of the head 38 within the cage I8 acts to move the cam member from the retracted position shown in Figure lc to the extended position shown in Figure 2. In the latter position the operative surface 43 on the cam member engages the side wall of the well bore I on one side, thereby displacing the cage I8 into contact with the side wall on the other side of the bore hole II. In the latter position the side opening window 22 in the housing section I1 lies adjacent the side wall of the bore hole.

Downward motion of the silding head 38 is resisted by means of the coil spring 49 positioned at the lower end of the bore 4I. The spring 49 is positioned on a support collar 58 held in place by means of a retaining ring 5|. The lower end of the cage I8 is attached to a hollow plug `52. A replaceable bushing 53 is mounted in the piston 39 and provided with a central opening 52. The opening 52 is closed by a apper valve 54 pivotally supported at 55 and maintained in closed position by means of a relatively weak coil spring 58. When a supply of Huid under pressure is delivered to the space 51 above the piston 39, the apper valve 54 immediately opens and allows fluid to pass through the opening 52 and downwardly into the interior of the head 38. The fluid passes outwardly through the window 58 through which the cam member 43 operates and also passes downwardly through the openings 59 and 68 into the bore hole II. The opening 52 is proportioned to allow a relatively small rate of ilow of well fluid without offering back pressure sufcient to depress the piston 39. When the rate of iiow of well fluid is sufficiently high to actuate the turbine I9, the back passage caused by the restricted orifice 52 is sufficient to depress the sliding head 38 and extend the cam member 43 through the window 58. The function of the flapper valve 54 is to prevent detritus in the well hole from passing upwardly into the interior of the upper housing sections when the housing I3 is initially lowered into the hole on the end of the pipe string I8.

In orderto prevent excessive back pressure in the space 51 and thereabove, a relief valve assembly is provided on the piston 39. As shown in the drawings, this valve assembly includes a replaceable seat 6I cooperating with a valve head 62 which is guided for movement by means of lateral fins 53. The valve head is carried on a valve stem' 84 slidably mounted for movement within a guide 65 provided on the head 38. A coil spring 66 acts resiliently to maintain the valve head 62 in sealing relationship with respect to the valve seat 8|. When the pressure differential across the piston 39 exceeds a predetermined value the valve head 82 moves downwardly to permit iluid to flow through the central opening in the seat 6I.

Referring particularly to the construction of the retractable assembly 28, the pulling plug 18 is provided with a shoulder 1| for engagement by a conventional overshot (not shown). This plug .is attached to the upper end of the signal body 12 by means of threads 13 and pins 14. The lower end of the signal body 12 is connected by threads 15 to the upper end `of the cylindrical pipe 16. An annular piston 11 is slidably mounted within the cylindrical bore 18 of the pipe 18 and is proa vided with one or more sealing rings 19 and 88. A tube 8| extends centrally through the piston and is sealed therewith by means of the inner seal ring 88. The annular piston 11 moves downwardly with respect to the stationary pipe 16 and tube 8| when mud fluid under pressure enters the lateral port 95 in the pipe 1S andpasses into the space 82 above the annular piston 11. The piston 11 is thus free-floating and its function is to separate mud fluid in the chamber 82 from oil contained in the chamber 83 below the piston 11. The tube 8| is threadedly connected at its upper end to the signal rod 84 which is slidably mounted within the signal body 12. The rod 84 and its mounting are more fully described hereinafter.

The lower end of the pipe 15 is connected by threads 85 tothe driving body section 88. Pivoted dogs 81 are mounted in recesses 88 on the body S6, and compression springs 89 are provided to move the dogs in a direction to project the driving edges 98 thereof outwardly beyond the periphery of the Vbody 88. These dogs are adapted to engage within notches 9| formed on the turbine rotor 9 to provide a driving engagement for rotating the retrievable assembly 28. The lower end of the body 88 is connected by threads 92 to the shell 93 which encloses the relatively long coil spring 94.

The lower end of the tube 8| is connected by thread 99 to the upper end of the slotted member 91. As clearly shown in Figure '7 this member is provided with a flange 98 and a downwardly extending cylindrical part 99 having a transverse slot |88 formed therein. 'Ihe slot Ill receives a pair of upwardly extending lugs I8I carried on the collar |82. A cylindrical skirt |83 encircles the member 91 below the level of the ange 98 and is attached to the slotted member 91 by means of screw fittings |84. This skirt ID3 is provided with a pair of bayonet slots |05, each having an upper vertical portion |86, a central horizontal portion |91, and a lower downwardly extending vertical portion |88. Radially extending pins |89 are threadedly secured to circulation tube III! which extends through the collar |02 and slotted member 91. The pins |89 extend radially through openings provided in the collar |82 and project into the bayonet slots |85. The circulation tube III] extends downwardly through the shell 93 and carries an abutment piece III near its lower end. A forward piston II2 is supported on the upper end of the spring 94 and is slidably mounted within the cylindrical bore IIS of the shell 93. A bushing II4 fixed on the piston slidably receives the outer surface of the lower portion of the circulation tube H8.

The feed piston II2 is caused to move downwardly under hydraulic pressure delivered to the space I I5 in a manner described below. The piston moves downwardly within the bore |I3, compressing the spring 94, and eventually contacts the abutment piece I I I. This pulls the cir- Zculation tube ||8 downwardly and therefore moves the pins |89 downwardly within the upper portions |86 of the bayonet slot |85. A torsion spring IIB having its lower end secured to the skirt |83 at |I1 has its upper end secured to the collar |82 at I|8. `A distance piece in the form of a sleeve Illia is positioned within the spring IIS. Accordingly, when the radial pins H19 enter one end of the horizontal portion |81 of the bayonet slot |85, the torsion spring |18 turns the collar |02 through approximately 90 and brings the lugs |8I out of registry with the slot |89.

` piston l2.

This continued downward movement of the circulation tube brings. the lower tapered end ||9 of thelarge trigger collar |20 into Contact. with the inner portion of the latching lug |2|. The collar is attached to the circulation tube ||0 by means of the pin |22. The latching lug |2| is pivotally mounted on a vertical pin |23 fixed on the upper end of the valve body |24, and it operates in a horizontal slot formed in the valve body. As shown in Figures 4 and l2, when the lower tapered end ||9 on the trigger collar |22 engages one end of the latching lug |2|, it moves the other end radially inwardly so that said other end no longer overlies the shoulder |26 formed near the upper end of the valve housing |21. The latching lug |2| is arcuate in shape so that in its inoperative position it lies completely within the annulus formed between the bore |28 of the valve housing |21 and the external cylindrical surface of the valve body |24. When the arcuate latching lug |2| is in this inoperative position as shown by the dotted lines in Figure 12, the valve body |24 is released for movement with respect to the valve housing |21.

The valve body |24, valve housing |21, and associated parts comprise a four-way valve assembly generally designated |29. The function of this four-way valve assembly is to admit pressure fluid above the feed piston to move it downwardly while exhausting fluid below the piston, and then when the feed piston has reached the lower end of its stroke to reverse the action so that the pressure uid is applied beneath the piston and exhausted above it. As shown in the drawings, Figure 4 shows the passageways of the valve assembly |29 arranged to causel downward movement of the feed piston ||2. Oil under pressure from the chamber 83 below the barrier piston 11 passes downwardly through the interior of the body section and into the. passageway |30 formed in the upper end of the valve body |24. This passageway communicates by way of port |3| with an annular groove |32 provided in the valve housing |21. This annular groove |32 is also in communication with passageway |33 formed in the valve housing |21 and communicates with the space ||5 above the feed piston ||2. The space |34 below the feed piston ||2 communicates by way of lateral port |35 and longitudinal passage |36 formed in the wall of the shell 93 with the circumferential groove |31 formed in the valve housing |21 between the sealing rings |38. This annular groove is connected by lateral port |39 to annular groove |40 formed in the outer surface of the valve body |24. A port |4| connects this groove |40 to the annular space |42 between the circulation tube ||9 and the valve body |24. A port |43 is provided through the wall of the circulation tube 0 so that pressure uid exhaustingfrom the space |34 below the feed piston ||2 passes down wardly through the interior of the tube ||0.

Figure 5 shows the position of the passageway in the four-way valve assembly |29 correspond-k ing to delivery of pressure fluid to the space |34 below the feed piston |2 and exhaust ofA pressure iiuid from the space- ||5 abovev the feed The valve body |24 is latched` with respect to the valve housing |21 while the valve parts are inposition to cause the feed piston H2 to move downwardly, but at the lower end of its stroke the circulation tube ||0 is moved axially to trip the latching lug |2| and to release the valve body |24 for axial movement with respect to the valve housing |21. The valve body |24 moves downwardly against the action of the compression springs |44 because of the higher fluid pressure which exists within the space |45 as compared to the relatively low back pressure in the interior of the circulation tube ||0 and hence in space |48. The spring |44 rests on a closure plug |48 threaded to the lower end of the valve housing |21. Upon release of the arcuate latch |2| the valve body |24 moves with a snap action from the position shown in Figure 4 to the position shown in Figure 5. In the latter position passageway |33 connects the space ||5 for exhaust through the interior of the circulation tube ||0 by way of port |4|, annular space |42, and port |43 in the wall of the circulation tube ||0. At the same time, pressure iluid is admitted from the space |45 above the four-way valve assembly |29 into the passageway |30 and ports |41 and |39. The pressure uid then passes into ring groove |31 and into the passageway |36 formed in the wall of the shell 93. The pressure fluid emerges through port |35 into the space |34 below the piston ||2.

The passageway |38 may be formed in the wall of the shell 93 in any convenient manner. I prefer to form a long V-shaped slot extending inwardly from the outer periphery of the shell 93 and then to weld a cover strip over the outer portion of the slot to form the passageway |36.

When the feed piston approaches the upper end of its stroke it engages the stop element |49 which is xed on the circulation tube H0 and positioned within the space H5. This stop element may comprise a pair of half rings mounted in a circular recess |50 on the tube ||0 and held in place by means of a retaining ring |5|. Continued upward movement of the feed piston ||2 carries the stop element |49 and circulation tube H0 upwardly therewith. Upward motion of the feed piston continues until the upper surface of the stop element |49 engages the lower side |52 of the closure collar |48. The fluid pressure which acts to move the feed piston downwardly applies an equal force tending to raise the retrievable assembly 20 upwardly away from the supporting shoulder 8. However, this force is overbalanced by the weight of thegassembly plus the relatively large downward force applied to the assembly by the pressure of the mud fluid within the interior of the drill string |0. The result is that the sleeve 9 of the retrievable assembly 20 remains in position while the core bit 2|l is advanced to the formation.

Rotary motion transmitted from the turbine rotor 9 to the driving body 88 through the pivoted lugs 81 reaches the feed piston ||2 through the sleeve 93 and the long coil spring 94. The coil spring 94 therefore provides a resilient drive for rotating the feed piston and its associated parts as well as for assisting in returning the feed piston |2 to its upper position. A hollow piston rod |53 extends downwardly from the-feed piston and through the interior of the coil spring 94. The hollow piston rod |53 is slidably received in bore |54 in the closure |55 attached to the lower end of the shell 93. A seal ring |56 prevents leakage between the closure and hollow piston rod. The projecting end |51 of the hollow piston rod |53 is threadedly connected to a driving'y collar |58. The driving collar |58 is threadedly connected at |59 to the core-taking unit` generally designated |60. This unit |60 includes a pair of mounting members |6| secured to the opposite ends of a metallic coil spring |62. The upper member |6| is threadedly engaged with the driving collar |50. The spring |62 is imbedded in a cylindrical sheath of rubber |64 to form an integral resilient tube |63.

An annular core-cutting bit 2| of any preferred design is threaded to the member |63 at |65. This annular core-cutting bit may be provided with the usual formation-engaging teeth |66. Any preferred form of core catcher assembly |61 may be provided. As shown in the drawings this core catcher assembly includes a ring |68 having a plurality of lingers |69 pivotally attached thereto at |10. It is the function of the lingers |69 to prevent a core from moving out ofthe interior of the core-taking assembly |60 once it has entered.

The driving collar |58 is slidably received Within the bore |11 of the tail pipe |18 which extends from the curved footpiece |19 to the supporting assembly 32 for the thrust bearing 24. The curved passage in the footpiece |19 communicates with the side opening window 22 described above. An insert member |0| may be mounted in the lower end of the curved passage and provided with an inner rubber sleeve |82 to resist wear. As the rotating hollow piston rod |53 moves downwardly within the tail pipe |18 it causes the resilient tube |63 to rotate and to move outwardly through the window 22. The coring head 2| drills into the formation, leaving a stationary central axial core projecting into the flexible core-receiving tube |1| The driving tube |63 must be sufiiciently flexible to rotate within the curved footpiece |19, must carry adecuate torque for turning the bit 2|, and must carry axial load for forcing the bit 2| into the formation. I have found that the tube |53 composed of a metallic coil spring imbedded within a cylindrical rubber sheath performs these various functions in a highly satisfactory manner. The service on this part is severe, and it is absolutely essential that no fractures or failures occur. The particular construction illustrated has been found to give excellent results in actual tests. At the end of`a long period of service the rubber-metal bond may be broken or the rubber itself may rupture; at such time the old rubber may be burned off and new rubber may be molded about the spring.

Mud fluid is supplied to the cutting bit 2| as is customary in rotary well drilling practice. This mud fluid enters the screen |33 provided on the signal body 12 and passes inwardly through ports |54 and |85. The mud fluid then passes through the restriction bean 136 and enters the upper end of the tube 8|. The lower end of this tube is in communication with the upper end of the circulation tube ||0 andA hence ytube |63.

When the feed piston has moved to the lower end of its travel and then has fully retracted as explained above, the flexible driving tube |63 and coring head 2| are withdrawn back into the interior of the housing i3. Means are provided for signaling to the operator at the ground surface when this cycle has been completed. As shown in the drawings, this means includes a restriction valve generally designated lSl. This valve acts to restrict the flow of mud fluid entering the device from the sub l2 when the coretaking cycle has been completed. The restriction in the circulation path is reiiected by an increase in pressure at the surface, and this is indicated on a pressure gage (not shown). When the pressure suddenly increases the operator is informed that the core-taking cycle has been completed. An overshot (not shown) is then lowered into the well pipe I0 on a wire line to engage the pull plug 10 and the entire retrievable assembly 2t! is withdrawn as a unit.

The signal operating means shown in the drawings includes the latching parts |82 and |93 which are substantially duplicates. As shown in Figures 3a, 6 and ll, each of these parts is substantially U-shaped with one leg of each engaging within the opening of the other. Coil springs |64 are confined within the parts |92 and |93 and act resiliently to maintain them in retracted position. The latching parts are arranged to operate in a cross-slot provided in the signal body 12 and are arranged to underlie an internal shoulder iS formed on the signal valve |01. When the latching parts are retracted as shown in Figure 6 so that they no longer underlie the shoulder |96,M the signal valve |01 drops by gravity and by the velocity effect of the mud fluid stream passing through thel restricted opening |93 formed in the insert piece 19%. A coil spring 200 may be used if desired to supplement the action of gravity and of the mud fluid stream to move the signal valve from the inoperative position shown in Figure 3a to the operative position shown in Figure 5. A bulbous rubber' sleeve 20| may be fixed on the valve |1, and this sleeve closely approaches the diameter of the opening |98 but does not completely fill it so that when the signal valve |91 is in the position shown in Figure 6 the flow of mud fluid is restricted but not entirely shutoff.

Means are provided for retracting the latching members |92 and |93, and as shown in the drawings this means includes a pointed pin 202 fixed on the upper end of the signal rod 84. The

signal rod is slidably mounted within the signal body 12 and is provided with a vertical slot 203 forreception of a pin 204 xed on the body 12.

' The slot and pin cooperate to prevent relative rotary movement kbetween the rod 84 and body 112. y Since therod Si! is carried onthe upper end lil of the tube 8| it moves as a unit therewith. Upward movement of the rod 8| and hence of the rod 84 and latch actuating pin 202 is caused by upward movement of the circulation tube when the feed piston H2 returns to the upper end of its stroke. The downward movement of the feed piston resulted in movement of the lugs |0| out of the slot |00 as described above and repositioning of the lugs |0| in a position out of registry with the slot |00. Accordingly, when the circulation tube ||0 is moved upwardly as the feed piston completes its operative cycle, the upper faces 205 of the lugs |0| engage the lower surfaces 206 on the cylindrical extension 99 of the member 91. Continued upward movement. of the feed piston ||2, circulation tube ||0 and lugs |0| serves to raise the member 9'| and tube 8|. This in turn moves the signal rod 84 upwardly to cause the latch operating pin 202 to retract the latch members |92 and |93. The sig-l nal valve |91 then moves downwardly as described above to restrict the flow of mud fluid and thereby apprise the operator that the retractable unit is ready for removal through the pipe string |0.

When the retractable unit 20 reaches the surface the core-taking unit |60 is removed from the driving collar |58 by disengaging the threads |59. The core is then removed from the tube for geological analysis. The plug 201 in the; 30 side of the body 86 is removed to permit introduction of a new supply of oil or other hydraulic fluid into the space 83 below the barrier piston 87. A suitable tool such as, for example, the crank tool 208 as shown in Figure 14, is in-,35 serted through the open lower end of the hollow piston rod |53. A laterally projecting part 209 on the end of the tool 208 is inserted into the bayonet slot 2|0 in the fitting |81 on the lower end of the circulation tube 0. The crank isf-40 turned to oppose the action of the torsion spring ||6 and a thrust is applied to move the laterally extending pins |09 into the upper vertical portions |0 of the bayonet slots |05. This action resets the tool for use and in effect contracts the ,i overall length of the tubes l0 and 8|. A coil spring 2|| returns the valve latch |2| to its operative position. The signal valve 91 is raised against the action of the coil spring 200 to permit the latching members |92 and |93 to move.; outwardly into the operative position. A new core-taking assembly is threaded to the driving collar |58 and the tool is ready for lowering again into the pipe string 0 on a wire line.

When the supply of mud fluid is cut off at `55 the surface the positioner unit generally designated 31 moves back to its inoperative position as shown in Figure 1c. The pipe string may then be manipulated to present a new location for taking another core. This process may be repeated and as many side wall sample cores taken as desired without requiring that the pipe string I0 be removed from the well bore My invention is not limited to devices for taking a core from formation adjacent a well bore, but may also be employed in connection with the drilling of lateral drainage holes in tight formations, and may also be used for drilling holes in casing. When a hole is to be drilled in the casing the surface 48 on the wedge cam 43 is curved to fit the inner surface of the casing wall and may be serrated to prevent slipping. It will be understood that in this specification and claims the words bore hole include either a cased or an uncased hole. In this connection the devices may be used as a coring tool for taking a formation sample through the wall of the casing. In such cases the rotary bit rst cuts a hole in the wall of the casing and is subsequently eX- tended through the hole to take a core from the well formation. In the modied form of my invention illustrated in Figure 13, the barrier piston is not used. Instead mud fluid enters through the port a and passes through the annular passage 220 into the space 22|. Mud fluid also passes inwardly through the screen |83a and into the interior of the signal rod 84a through lateral ports |84a and |85a. in the manner described above. The remainder of the device in this modified form is substantially the same as that previously described, and the similar parts are designated by the same numeral with the suffix a.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claims.

I claim:

1. Drilling apparatus for use in a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, a prime mover in the housing having a rotary drive element, and a retrievable drilling unit including a rotary cutting tool adapted to be lowered through the interior of the pipe string into driving relationship with said drive element.

2. Drilling apparatus for use in a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, a prime mover in the housing having a rotary drive element, a retrievable drilling unit including a rotary cutting tool adapted to be lowered through the interior of the pipe string into the housing, the drive element and the drilling unit having cooperating parts providing a releasable driving connection whereby the retrievable drilling unit and cutting tool may be rotated by the rotary drive element.

3. Drilling apparatus for use in a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, a prime mover in the housing driven by pressure fluid supplied through said pipe string, said prime mover having a rotary drive element, a retrievable drilling unit including a rotary cutting tool adapted to be lowered through the interior of the pipe string into the housing, and cooperating parts on the drive element and the drilling unit providing a releasable driving connection whereby the retrievable drilling unit and cutting tool may be rotated by the rotary drive element.

4. Drilling apparatus for use in a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, a prime mover in the housing driven by pressure fluid supplied through said pipe string, said prime mover having a rotary drive element, a retrievable drilling unit including a rotary cutting tool adapted to be lowered through the interior of the pipe string into the housing, cooperating parts on the drive element and the drilling unit providing a releasable driving connection whereby the retrievable drilling unit and cutting tool may be rotated by the rotary drive element, and a fluid actuated feed element on the retrievable unit for advancing the cutting tool.

5. Drilling apparatus for use in a bore hole,

comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, a fluid driven turbine in the housing having a rotor, the turbine being driven by pressure fluid supplied through the pipe string, a retrievable drilling .unit including a rotary cutting tool adapted to be lowered through the interior of the pipe string into driving engagement with the rotor, and a Huid actuated feed element on the retrievable unit for advancing the cutting tool.

6. Apparatus for securing a core sample from the formation .adjacent a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, a prime mover in the housing having a rotary drive element, a retrievable sampling unit adapted to be lowered through the interior of the pipe string into the housing, cooperating parts on the sampling unit and drive element forming a releasable driving connection whereby the sampling unit may be driven by the rotary drive element, the sampling unit including a rotary coring tool and a feed element for advancing the coring tool into the formation.

'7. Apparatus for securing a core sample from the formation adjacent a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, a prime mover in the housing having a rotary drive element, a retrievable sampling unit adapted to be lowered through the interior of the pipe string into the housing, cooperating parts on the sampling unit and drive element forming a releasable driving connection whereby the sampling unit may be driven by the rotary drive element, the sampling unit including a rotary coring tool and a feed element for advancing and retracting the coring tool into and out of the formation.

8. Apparatus for securing a core sample from the formation adjacent a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, a fluid-operated turbine in the housing having a rotor driven by pressure fluid supplied through the pipe string rotor, a retrievable sampling unit adapted to be lowered through the interior of the pipe string into the housing, cooperating parts on the sampling unit and rotor forming a releasable driving connection whereby the sampling unit may be driven by the turbine rotor, the sampling unit including a rotary coring tool and a fluid-operated feed element for projecting and retracting the coring tool into and out of the formation.

9. Apparatusfor securing a core sample from the side wall of a bore hole, comprising in combination: a housing adapted to be secured to a pipe string'and positioned within the bore hole, the housing being provided with a lateral opening in a side wall thereof, a prime mover in the housing having a rotary drive element, a retrievable sampling unit adapted to be lowered through the interior of the pipe string into the housing, cooperating parts on the 'sampling unit and drive element forming a releasable driving' connection whereby the sampling unit may be driven by the rotary drive element, the sampling unit including a rotary coring tool adapted to extend through the said lateral opening in the housing.

1G. Apparatus for securing a core sample from the side wall of a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole,

rotary drive element, the sampling unit including a rotary coring tool and a feed element for projecting the coring tool through the said lateral vopening in the housing.

ll. Apparatus for securing a core sample from the side wall of a bore hole, comprising in oombinationz a housing adapted to be secured to a pipe string and positioned within the bore hole, the housing being provided with a lateral opening in a side wall thereof, a fluid-operated turbine in the housing having a rotor driven by pressure fluid supplied through the pipe string, a retrievable sampling unit adapted to be lowered through the interior of the pipe string into the housing, cooperating parts on the sampling unit and rotor forming a releasable driving connection whereby the sampling unit may be driven by the turbine rotor, the sampling unit including a rotary coring tool and a fluid-operated feed element for projecting and retracting the coring tool through the said lateral opening in the housing.

12. Apparatus for securing a core sample from the side wall of a -bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned Iwithin the bore hole, the housing being provided with a lateral opening in a side wall thereof, an hydraulically actuated member on the housing engageable wit with the side wall of the bore hole for moving the housing laterally within the bore hole to position said lateral opening against the side wall surface of the bore hole, a fluid-operated tur-bine in the housing having a rotor driven by pressure fluid supplied through the pipe string, a retrievable sampling unit adapted to -be lowered through `the interior of the pipe string into the housing, cooperating parts on the sampling unit and rotor forming a releasable driving connection whereby the sampling unit may be driven by the turbine rotor, the sampling unit including a rotory coring tool and a duid-operated feed element for projecting and retracting the coring tool through the said lateral opening in the housing.

13. Apparatus for securing a core sample from the side -wall of a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, the housing being provided with a lateral openn ing in a side wall thereof, a laterally movable member on the housing engageable with the side wall of the bore hole for moving the housing laterally within the bore hole to position said lateral opening against the side wall surface of the 'bore hole, a prime mover in the housing having a rotory drive element, a retrievable sampling unit adapted to be lowered through the interior of. the pipe string into driving engagement with said drive element, the sampling unit including a rotary coring tool and a feed element for projecting and retracting the coring tool through said lateral opening in the housing.

14. Apparatus for securing a core sample from the side wall of a -bore hole, comprising in combination: a housing adapted to be secured to a lr`pipe string and positioned within the bore hole, the housing being provided with a lateral opening in a side wall thereof, a prime mover in the housing, the prime mover having an axially eX- tending drive element provided with an axial opening, a retrievable sampling unit adapted to be lowered through the interior of the pipe string into driving engagement lwith said drive element, the sampling unit including a rotary coring tool at its lower end adapted to pass through said axial opening in the drive element.

15. Apparauts for securing a core sample from the side `wall of a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the -bore hole, the housing being provided with a lateral opening in a side wall thereof, a fluid operated turbine in the housing having a rotor driven by pressure fluid supplied through the pipe string, the rotor having an axial opening, a retrievable sampling unit adapted to be lowered through the interior of the pipe string into the housing, cooperating parts on the sampling unit and rotor forming a releasable driving connection whereby the sampling unit may be driven by the turbine rotor, the sampling unit including a coring tool at its lower end adapted to pass through said axial opening in the drive element- 16. Apparatus for securing a core sample from the side wall of a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, the housing being provided with a lateral opening in a side Wall thereof, a uid operated turbine in the housing having a rotor driven by pressure fluid supplied through the pipe string, the rotor having an axial opening, a seat formed in the opening, a retrievable sampling unit adapted to be lowered through the interior of the pipe string to rest on said seat, cooperating parts on the sampling unit and rotor forming a releasable driving `connection whereby the sampling unit may be driven by the turbine rotor, the sampling unit including a coring tool at its lower end adapted to pass through said axial opening in the drive element, the upper end of the retrievable sampling unit extending above the turbine rotor.

17. Drilling apparatus for use in a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned Within the bore hole, a prime mover in the housing having a rotor drive element, said element being provided with an axial opening, a retrievable drilling Iunit adapted to be lowered through the interior of the pipe string into driving relationship with said drive element, said retrievable drilling unit including a rotary cutting tool adapted to pass through said axial opening in the rotary drive element.

18. Drilling apparatus for use in a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, the housing being provided with a lateral opening in a side wall thereof, a prime mover in the housing having a rotary drive element, a retrievable drilling unit adapted to be lowered through the interior of the pipe string into the housing, cooperating parts on the drilling unit and drive element forming a releasable driving connection whereby the drilling unit may be driven by the rotary drive element, the drilling unit including a rotary cutting tool adapted to extend through the said lateral opening in the housing.

19. Drilling apparatus for` use .in a bore hole, comprising in combination:l a housingadapted .to

be secured to a pipe string and positioned within the bore hole, the housing being provided with a lateral opening in a side Wall thereof, a iluid operated turbine in the housing having a rotor driven by pressure fluid supplied through the pipe string, a retrievable drilling unit adapted to be lowered through the interior of the pipe string into the housing, cooperating parts on the drilling unit and rotor forming a releasable driving connection whereby the drilling unit may be driven by the turbine rotor, the drilling unit including a rotary cutting tool and a uid operated feed element for projecting and retracting the cutting tool through the said lateral opening in the housing.

20. Drilling apparatus for use in a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned Within the bore hole, a prime mover in the housing driven by pressure uid supplied through said pipe string, said prime mover having a rotary drive element, a retrievable drilling unit including a rotary cutting tool adapted to be lowered through the interior of the pipe string into the housing, cooperating parts on the drive element and the drilling unit providing a releasable driving connection whereby the retrievable drilling unit and cutting tool may be rotated by the rotary drive element, a fluid actuated feed element on the retrievable unit for advancing and retracting the cutting tool, a signal valve movable from an inoperative position providing a relatively unrestricted passage from the drill string into the housing to an operative position restricting said passage, the signal valve inoperative position imposing a back pressure on the fluid in the pipe string to provide a signal at its upper end, and mechanical linkage operable upon completion of retracting movement of the cutting tool to move the valve to operative position.

21. Apparatus for securing a lcore sample from the side wall of a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, the housing being provided with a lateral opening in a side wall thereof, a fluid-operated turbine in the housing having a rotor driven by pressure uid supplied through the pipe string, a retrievable sampling unit adapted to be lowered through the interior of the pipe string into the housing, cooperating parts on the sampling unit and rotor forming a releasable driving connection whereby the sampling unit may be driven by the turbine rotor, the sampling unit including a rotary coring tool and a fluid-operated feed element for projecting and retracting the coring tool through the said lateral opening in the housing, a signal valve movable from an inoperative position providing a relatively unrestricted passage from the drill string into the housing to an operative position restricting said passage, the signal valve in operative position imposing a back pressure on the iiuid in the pipe string to provide a signal at its upper end, and mechanical linkage operable upon completion of retracting movement of the curing tool to move the valve to operative position.

22. Apparatus for'securing a core sample from the side wall of a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned Within the bore hole, the housing being provided with a lateral opening in a side wall thereof, a retrievable sampling unit adapted to be lowered through the interior of the pipe string into the housing, the sampling unit including a coring tool adapted to extend through said lateral opening in the housing, a feed element operable to advance and retract the coring tool through said lateral opening, a-signal valvemovable from an inoperative position providing a relatively unrestricted passage from the drill string into the housing to an operative position restricting said passage, the signal valve in operative position imposing a back pressure on the fluid in the pipe string to provide a signal at its upper end, and mechanical linkage operable upon completion of retracting movement of the coring tool to move the valve to operative position.

A23. Apparatus for securing a core sample from thev side wall of a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, the housing being provided with a lateral opening in a side Wall thereof, a retrievable sampling unit adapted to be lowered throughl the interior of the pipe string into the housing, thev sampling unit including a coring tool adapted to extend through said lateral opening in the housing, a feed element operable by pressure fluid supplied through the pipe string to advance and retract lthe coring tool through said lateral opening, a valve movable from an inoperative position providing a relatively unrestricted passage from the drill string into the housing to an operative position restricting said passage, and mechanical linkage including a member movable by said feed element, said member including inter-engaging parts adapted to render the member 4effective to actuate the valve when the coring tool approaches its retracted position.v

24. VApparatus for securing a core sample from the side Wall of a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned Within the bore hole, the housing being provided with a lateral opening in a side Wall thereof, a retrievable sampling unit adapted to be lowered through the interior of the pipe string into the housing, the sampling unit including a coring tool adapted to extend through said lateral opening in the housing, a feed piston movable within a cylinder provided on the sampling unit by pressure fiuid supplied through the drill string and operably connected to advance the coring tool through said lateral opening in the housing, a valve movable from an inoperative position providing a relatively unrestricted passage from the drill string into the housing to an operative position restricting said passage, a latch device for maintaining the valve in its inoperative position, a member extending axially of the sampling unit and adapted to be moved axially by said feed piston, cooperating parts on said member adapted to render the member effective to trip the latch device to actuate the valve when the coring tool approaches its retracted position.

25. Apparatus for securing a core sample from the side wall of a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, the housing being provided With a lateral opening in a side wall thereof, a retrievable sampling unit adapted to be lowered through the interior of the pipe string into the housing, the sampling unit including a coring tool adapted to extend through said lateral opening in the housing, a feed piston positioned Within a cylinder provided on the sampling unit, said piston being movable in. response to pressure fluid supplied through said pipe string and operably connected to advance and retract the coring tool through said lateral opening in the housing, a valve movable from an inoperative position providing a relatively unrestricted passage for the pressure fluid from the drill string into the housing to an operative position restricting the flow of pressure fluid through said passage, a latch device for maintaining the valve in its inoperative position, a trip member extending axially of the sampling unit and adapted tobe moved axiallyby said feed piston, cooperating parts on said member adapted to increase the effective lengththereof upon completion of movement of the feed piston in a direction to advance the coring tool, and cooperating parts whereby said elongated trip member may release the latch device as the feed piston approaches its retracted position.

26. Apparatus for securing a core sample from the side wall of a bore hole, comprising in combination: a housing adapted to be secured `to a pipe string and positioned within the bore hole, the housing being provided with a lateral opening in a side Wall thereof, a retrievable sampling unit adaptedto be lowered through the interior of the pipe string into the housing, the sampling unit including a coring tool adapted to extend through said lateral opening in the housing, a feed piston positioned within a cylinder provided on the sampling unit, said piston being movable in response to pressure fluid supplied through said pipe string and operably connected to ad- Vance and retract the coring tool through said lateral opening in the housing, a valve movable from an inoperative position providing a relatively unrestricted passage for the pressure fluid from the drill string into the housing to an operative position restricting the flow of pressure iiuid through said passage, a latch device for maintaining the valve in its inoperative position, a sectional trip member adapted to release the latch device whereby the valve may move to operative position to restrict the flow of pressure fluid, a first stop on a lower section of said member engageable by said feed piston near one end of its travel, cooperating parts connecting the lower section with an upper section of said member and adapted to increase the effective length of the sectional member upon movement of the stop by the feed piston, and a second stop on the lower section engageable by the feed piston near the other end of its travel to move the elongated sectional member in a direction to release the latch device.

27. Drilling apparatus for use in a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, a drilling unit including a cutting tool positioned within the housing, a feed element on the drilling unit for advancing the cutting tool from the interior to the exterior of the housing, said feed element being subjected on one side to pressure fluid supplied through the pipe string and on the other side to pressure within the bore hole, the housing including a member provided with an orifice through which pressure fluid from the interior of the pipe string escapes into the bore hole whereby a pressure differential is maintained between the interior and exterior of the pipe string.

28. Apparatus for securing a core sample from the formation adjacent a bore hole, comprising in combination: a housing adapted to be secured to a pipestrng and positioned within the' bore hole, a fluid operated turbine in the housing having a rotor driven by pressure fluid supplied through the pipe string, a retrievable sampling unit adapted to be lowered through the interior of the pipe string into driving relationship with the turbine rotor, the sampling unit including a rotary coring tool. a feed element on the sampling unit for advancing the coring tool outwardly from the interior of the housing, said feed element being subjected on one side to pressure fluid supplied through the pipe string and on the other side to pressure within the bore hole, the housing including a member provided with an orice through which pressure fluid from the interior of the pipe string escapes into the bore hole whereby a pressure differential is maintained between the interior and exterior of the pipe string.

29. Apparatus for securing a core sample from the side wall of a bore hole, comprising in combination: a housing adapted to be secured to pipe string and positioned within the bore hole, the housing being provided with a lateral opening in a side wall thereof, a fluid-operated turbine in the housing having a rotor driven by `pressure iiuid supplied through the pipe string, a retrievable sampling unit adapted to be lowered through the interior of the pipe string into the housing, cooperating parts on the sampling unit and rotor forming a releasable driving connection whereby the sampling unit may be driven by the turbine rotor, the sampling unit including a rotary coring tool, a feed element on the drilling unit for advancing the rotary coring tool through the said lateral opening in the housing, said feed element being subjected on one side to pressure uid supplied through the pipe string and on the other side to pressure within the bore hole, the housing including a member positioned below the turbine and provided with an orifice through which pressure fluid may escape from the interior of the pipe string into the bore hole.

30. Drilling apparatus for use in a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned Within the bore hole, a drilling unit including a cutting tool positioned within the housing, a feed element on the drilling unit for advancing the cutting tool from the interior of the housing into the formation adjacent the bore hole, said feed element being subjected on one side topressure fluid supplied through the pipe string and on the other side to pressure within the boie hole, the housing including a member provided with an orifice through which pressure fluid from the interior of the pipe string escapes into the bore hole, a movable valve element positioned to restrict fiow through the orifice, and a spring acting to move the valve in a flow-restricting direction.

31. Apparatus for securing a core sample from the side wall of a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, the housing being provided with a lateral opening in a side wall thereof, a fluid-operated turbine in the housing having a rotor driven by pressure fluid supplied through the pipe string, a retrievable sampling unit adapted to be lowered through the interior of the |pipe string into the housing. cooperating parts on the sampling unit and rotor forming a releasable driving connection whereby the sampling unit may be driven by the turbine rotor, the sampling `unit including a rotary coring tool and a iiuid-operated feed element for projecting and retracting the coring tool through the said lateral opening in the housing, the housing including a member provided with an orifice through which pressure fluid from the interior of the pipe string may escape into the bore hole, a movable valve element positioned to restrict iiow through the orifice, and a spring acting to move the valve in a now-restricting direction.

32. Apparatus for securing a core sample from the formation adjacent a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, a prime mover in the housing having a rotary drive element, a retrievable sampling unit adapted to be lowered through the interior of the pipe string into the housing, cooperating parts on the sampling unit and drive element forming a releasable driving connection whereby the sampling .unit may be driven by the rotary drive element, the sampling unit including a rotary coring tool 'and a feed element for advancing and retracting the coring tool into and out of the formation, a barrier near the lower end of the retrievable sampling unit adapted to exclude bore hole 'detritus from the interior of the unit while it is being lowered through the pipe string, the barrier having a port extending therethrough, and a valve member normally closing the port and movable to an inoperative position by fluid pressure within said unit.

33. Drilling apparatus for use in a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, a drilling unit in the housing including a rotary cutting tool, a feed piston positioned within a cylinder provided on the drilling unit, a movable barrier member on the drilling unit subjected on its upper side to pressure of a first fluid supplied through said pipe string, the drilling unit being provided with a passage for a second fluid, the passage connecting the lower side of the barrier member to the cylinder, whereby the feed piston moves in response to motion of the barrier member to move the cutting tool out of the housing.

34. Drilling apparatus for use in a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, a drilling unitl in the housing including a rotary cutting tool, a feed piston positioned within a cylinder provided on the drilling unit, a movable barrier member on the drilling unit subjected on its upper side to pressure of a first uid supplied through said pipe string, the drilling unit being provided with a passage for a second iiuid, the passage connecting the lower side of the barrier member to the cylinder, whereby the feed piston moves in response to motion of the barrier member to move the cutting tool out of the housing', and a valve device operatively interposed in said passage and adapted to deliver the second uid into the cylinder either above or below the feed piston.

35. Apparatus for securing a core sample from the side wall of a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned within the bore hole, the housing being provided with a lateral opening in a side wall thereof, a retrieveable sampling unit adapted to be lowered through the interior of the pipe string into the housing, the sampling unit including a coring tool adapted to extend through said lateral opening in the housing, a feed piston positioned with a cylinder provided on the sampling unit, and operably connected to advance and retract the ooring tool through said lateral opening in the housing, a, movable barrier member on the sampling unit subjected on its upper side to pressure uid supplied through said pipe string, the sampling unit being provided with an oil filled .passage connecting the lower side of the barrier member to the cylinder, whereby the feed piston moves in response to motion of the barrier member to move the coring tool through said lateral opening in the housing.

36. Apparatus for securing a core sample from the side Wall of a bore hole, comprising in combination: a housing adapted to be secured to a pipe string and positioned Within the bore hole, the housing being provided With a lateral opening in a side Wall thereof, a retrievable sampling unit adapted to be lowered through the interior of the pipe string into the housing, the sampling unit including a coring tool adapted to extend through said lateral opening in the housing, a feed piston positioned with a cylinder provided on the sampling unit, and operably connected to advance and retract the coring tool through said lateral opening in the housing, a movable barrier member on the sampling unit subjected on its upper side to pressure fluid supplied through 22 said pipe string, the sampling unit being provided with an oil lled passage connecting the lower side of the barrier member to the cylinder, whereby the feed piston moves in response to motion of the barrier member to move the coring tool through said lateral opening in the housing, and a valve device operatively interposed in said passage and adapted to deliver oil into the cylinder either above or below the feed piston.

PAUL DEAN CORNELIUS.

REFERENCES CTED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,886,829 Lee Nov. 8, 1932 1,999,051 Kennedy Apr. 23, 1935 2,252,620 DeLong Aug. 12, 1941 2,296,161 Hall, Jr. Sept. 15, 1942 2,327,023 Danner Aug, 17, 1943 2,487,203 Wilber Nov. 8, 1949