US3430713A

US3430713A - Formation-sampling apparatus

Info

Publication number: US3430713A
Application number: US649929A
Authority: US
Inventors: C P Lanmon
Original assignee: Schlumberger Technology Corp
Current assignee: Schlumberger Technology Corp
Priority date: 1967-06-29
Filing date: 1967-06-29
Publication date: 1969-03-04
Anticipated expiration: 1986-03-04

Description

1 March 4, 1969 c P LANMON n FORMATION SAMPLING APPARATUS Sheet 01'5 Filed June 29. 1967' R 0m N mw am a z C March '4, 1969 c p LANMQN'U 3,430,713

FORMATION-SAMPLING APPARATUS Filed June 29, 1967 Sheet 2 015 C P Ian/77017 INVENTOR ATTORN c P LANMON ll FORMATION-SAMPLING APPARATUS March 4, 196? Sheet Filed June 29, 1967 C P law/770x231 INVENTOR C P LANMON ll FORMATION-SAMPLING APPARATUS March 4,1969

Filed June 29, 1967 INVEN T 0R United States Patent Ofilice 3,430,713 Patented Mar. 4, 1969 3,430,713 FORMATION-SAMPLING APPARATUS C P Lanmon II, Friendswood, Tex., assignor to Schlumberger Technology Corporation, Houston, Tex., a corporation of Texas Filed June 29, 1967, Ser. No. 649,929

US. Cl. 17578 44 Claims Int. Cl. E21b 49/02 ABSTRACT OF THE DISCLOSURE The particular embodiments described herein as illustrative of various forms of the invention are directed to borehole apparatus for obtaining and collecting a plurality of elongated samples from earth formations traversed by the borehole. To accomplish this, the disclosed tool includes cutting wheels that are arranged to cooperate with various guide systems in such a manner that the cutting wheels will be extended and make cuts along the face of an adjacent formation as a carrier supporting the wheels is moved longitudinally. When these cuts are completed, the cutting wheels are retracted by the guide systems and, upon reversal of the direction of the carriers travel, returned to their initial position while still retracted. One or more selectively-operable sample receivers are provided to receive formation samples and, by virtue of certain motion-translation means, keep these samples segregated from one another.

Accordingly, as will subsequently become more apparent, the present invention pertains to new and improved earth formation sample-taking apparatus; and, more particularly, this invention relates to sample-taking apparatus for obtaining continuous samples of earth formations along a substantial interval of the wall of a previously drilled borehole and to means for operating such apparatus.

Heretofore, formation samples have usually been obtained from previously drilled boreholes by explosively propelling into the adjacent wall of a borehole one or more tubular bodies or so-called bullets having appropriately arranged forward cutting edges. As these bullets penetrate the borehole wall, a generally cylindrical core of the formation material is driven into each bullet so that, when the bullets are subsequently retrieved, the cores in each will be recovered at the surface for examination. Typical of such core-taking bullets are those shown in Patents Nos. 2,678,804, 2,923,530, 3,072,202 and 3,220,490.

It is recognized, of course, that although such coretaking bullets have been highly successful, the most ideal arrangement would be to obtain a continuous sample of an earth formation from along a substantial vertical interval of a borehole. Heretofore, this has not been commercially feasible at least from boreholes that have been previously drilled.

One tool as shown in Patent No. 3,173,500 has been proposed, however, in which a pair of rotatable cutting wheels are cooperatively arranged to be extended outwardly to cut their way into an adjacent formation. Then, as they are slowly raised, the cutting wheels will cut a single elongated wedge-shaped formation sample out of the borehole wall. This sample is caught by the tool and returned to the surface. To elevate the cutting wheels of this tool and their driving motor, a large piston is dis posed in an elongated piston cylinder and connected to the driving motor by a long shaft extending out of the lower end of the piston chamber. A hydraulic fluid is confined in the hydraulic chamber above the piston and initially prevented from entering an empty dump chamber in the tool by a remotely operated normallyclosed valve.

When the driving motor and cutting wheels in this patented tool are to be elevated, the remotely operated valve is Opened so that the hydrostatic pressure of the borehole fluids acting on the exposed face of the piston will pull the driving motor upwardly as the hydraulic fluid is slowly displaced by the piston into the dump chamber. An outwardly projecting guide pin on the motor is received in a somewhat U-shaped guide slot in the support, which slot is arranged to extend the cutting wheels and then retract them at the end of the travel of the driving motor. It is, of course, apparent that this tool can obtain only one formation sample during a single trip into a borehole.

Accordingly, it is an object of the present invention to provide a new and improved core-slicing tool that is capable of taking a plurality of formation samples from one or more positions in a borehole during a single trip therein.

It is still another object of the present invention to provide means for controlling the operation of a core-slicing tool of this nature.

These and other objects of the present invention are obtained by arranging formation-sampling means includmg motive means, such as a suitable prime mover, to move longitudinally relative to a support. Formation-cutting means, such as a cooperatively arranged pair of rotatable cutting wheels, are connected by power-transmis- S1011 means to the prime mover. Guide means, such as appropriately-arranged channels or grooves on one of the relatively movable members and cooperative guide pins on the other of the relatively movable members, are provided so that the cutting wheels are successively extended, moved along a predetermined cutting path, and then retracted as the prime mover travels in a desired longitudinal direction in relation to the support. The guide grooves are also arranged to allow the cutting Wheels to then be returned to their initial position while still retracted. Means are also provided from which the position of the cutting wheels can be determined at the surface.

To recover the formation samples, sample-retrieving means with separate rotatable compartments are connected below the cutting means. As another aspect of I the present invention, therefore, motion-translating means are provided to successively index each of the samplereceiving compartments into position to collect a formation sample when it is cut. To accomplish this, the motion-translating means of the present invention include cam means rotatably coupled to the sample-receiving compartments and reciprocating cam-actuating means operatively engaged therewith and connected to the cutting means. During each cycle of the prime mover, the camactuating means are moved relative to the cam means to rotate the sample-receiving compartments a predetermined increment of a revolution. Each partial revolution of the cam means, therefore, brings one of the sample-receiving compartments into position to receive a formation sample. The novel features of the present invention are set forth with particularity in the appended claims. The operation together with further objects and advantages thereof, may best be understood by way of illustration and example of certain embodiments when taken in conjunction with the accompanying drawings, in which: FIGURE 1 depicts a core-slicing tool arranged in accordance with the present invention in a borehole and in position to obtain an elongated formation sample;

FIGURE 2 is a schematic representation of the intermediate portion of the tool shown in FIGURE 1;

FIGURE 3 is a cross-sectional view of one portion 3 of a preferred embodiment of the core-slicing tool shown in FIGURES 1 and 2;

FIGURE 4 is a schematic representation of one arrangement of a groove system arranged in accordance with the present invention;

FIGURE 5 is a cross-sectional view taken along the lines 55 in FIGURE 4;

FIGURES 6' and 8 depict alternative arrangements for groovesystems that are also in accordance with the present invention;

FIGURE 7 depicts an alternative arrangement of a guide pin that may be employed with the groove system illustrated in FIGURE 6;

FIGURE 9 is a sectional view of the motion-translating means of the present invention;

FIGURE 10 is a cross-sectional view taken along the lines 10-10 in FIGURE 9;

FIGURES 11 and 13 show alternate positions of the motion-translating means of the present invention;

FIGURE 12 is a cross-sectional view taken along the lines 12-12 in FIGURE 11;

FIGURE 14 depicts one arrangement of apparatus for use in determining the operating position of the cutting means used with the present invention;

FIGURE 15 is a schematic representation of an electronic circuit for use with the device shown in FIGURE 14; and

FIGURE 16 is a schematic view similar to FIGURE 2 but showing an alternate position-indicator also arranged in accordance with the present invention.

Turning now to FIGURE 1, a core-slicing tool 20 arranged in accordance with the present invention is shown suspended from a cable 21 in a borehole 22 and in position to obtain an elongated prismatic or wedge-shaped sample 23 from the adjacent wall of an earth formation 24. As seen in FIGURE 1, the tool 20 is preferably comprised of a number of tandemly connected housings 2529 suitably arranged for enclosing the various components of the tool. The upper housing 25 preferably encloses typical circuitry for locating the tool 20 at a desired position in the borehole 22 as well as circuitry for controlling the various components in the tool and transmitting power as well as information relating to the operation and position of the tool through the various conductors in the suspension cable 21.

The next lower housing 26 preferably includes suitable longitudinally spaced, hydraulically actuated pistons 30 for selectively extending a wall-engaging member 31 on the rear of the tool 20 laterally against one side of the borehole 22 to shift the forward face of the core-slicing tool in the opposite direction. In one manner of making the wall-engaging member 31 selectively operable from the surface, a hydraulic pump 32 and chamber 33 (shown only schematically) are arranged to extend the wallengaging member whenever hydraulic fiuid is pumped into the piston chambers behind the pistons 30 and to retract the wall-engaging member whenever hydraulic fluid is pumped into the piston chambers ahead of the pistons. It will be realized, of course, that by maintaining an increased hydraulic pressure behind the pistons 30, the wall-engaging member 31 will urge the forward face of the tool 20 against one wall of the borehole 22 with a corresponding force. Although the hydraulically actuated wall-engaging member 31 may be employed either alone or in conjunction with another extendible member, as at 34, near the lower end of the tool 20, other means such as, for example, outwardly biased springs, extendible arms, or the like, may also be used. In any event, the particular arrangement selected is of little consequence so long as the forward face of the tool 20 is near or against the borehole wall as a formation sample, such as at 23, is being taken.

The intermediate housing 27 of the tool 20 supports the selectively operable formation-sampling means 35 of the tool. As will subsequently be explained in greater detail with respect to FIGURES 2 and 3, these formation-sampling means 35 include cutting means such as a pair of similar cutting wheels 36 that are respectively mounted in converging vertical planes and arranged to rotate about independent, outwardly diverging axes themselves lying generally in the same horizontal plane and intersecting each other at a suitable angle. A longitudinal opening 37 is provided along the forward wall of the housing 27 diametrically opposite from the wall-engaging member 31. The cutting wheels 36 are suitably arranged and sized in relation to one another so that, when extended, their peripheral edges will pass through the housing opening 37 and all but come together at about the point of intersection of the three aforementioned planes. Thus, by moving the wheels 36 in unison in a generally vertical direction, the generally wedge-shaped or triangular prismatic sample 23 will be cut from the adjacent formation 24.

To gain entrance for the cutting wheels 36 into the formation 24, the present invention includes guide means 38 (to be subsequently described) for advancing the wheels outwardly through the housing opening 37 and in an inclined direction until they have reached their outermost lateral position. Then, after a longitudinal cut of a predetermined length has been made, the guide means 38 return the cutting wheels 36 along an upwardly inclined path and back through the housing opening 37 until they are fully retracted. To return the cutting wheels 36 to their original starting position, the guide means 38 then direct the wheels in the opposite longitudinal direction while still maintaining them fully retracted.

As will subsequently become apparent, the lower housing 29 of the tool 20 is arranged to receive a plurality of core samples and keep them segregated from one another. Generally speaking, the housing 29 is arranged in such a manner that a plurality of compartments therein (not shown in FIGURE 1) will be sequentially positioned by motion-translating means in the housing 28 thereabove to successively receive a formation sample 23 as the tool 20 is operated. In this manner, the tool 20 can be employed on a single trip in the borehole 22 to recover a large number of formation samples which are separately disposed in the compartments in a predetermined order.

Turning now to FIGURE 2, a schematic representation is shown of the intermediate housing 27 of the tool 20 in which the formation-sampling means 35 and guide means 38 of the present invention are confined. In general, the formation-sampling means 35 include an enclosed housing or enclosure 39 that is adapted for longitudinal travel in opposite directions in relation to the tool housing 27. In one manner of accomplishing longitudinal travel of the enclosure 39, the enclosure is secured, as by braces 40, to one or, preferably, two tubular members 41 (both seen in FIGURE 3). These tubular members 41 are in turn slidably disposed about substantially longer, paralleled longitudinal rods 42 (both seen'in FIGURE 3) that are secured only at their upper and lower ends to the tool housing 27 and spaced away from the rear wall thereof. Suitable packing means 43 are arranged on the opposite ends of the tubular members 41 for slidably sealing the interior of the tubular members around the elongated rods 42. Piston members 44 (only one shown in FIGURE 2) are respectively fixed at an intermediate position on each of the elongated rods 42 and slidably sealed relative to the internal bore of their associated tubular member 41 to define separate upper and lower fluid-

tight chambers

45 and 46 therein above and below each fixed piston member.

Accordingly, it will be appreciated that by developing a higher fluid pressure in the upper chambers 45 than that in the lower chambers 46, the tubular members 41 and enclosure 39 connected thereto will be moved upwardly along the elongated rods 42 relative to the tool housing 27. Similarly, by imposing a higher pressure in the lower hydraulic chambers 46 than that in the upper hydraulic chambers 45, the enclosure 39 will travel downwardly along the rods 42.

To develop such higher pressures in the

chambers

45 and 46, a suitable hydraulic pump 47 is mounted within the enclosure 39. Fluid lines 48 and 49 are respectively connected between the

hydraulic chambers

45 and 46 and the pump 47. By selecting a reversible-type hydraulic pump 47 and filling the

chambers

45 and 46 with a suitable hydraulic fluid, the pump can be selectively operated from the surface to transfer hydraulic fluid between the chambers to accomplish the desired travel of the enclosure 39 along the elongated rods 42. Although a so-called closed hydraulic system could be employed since the sum of the volumes in the

chambers

45 and 46 is substantially constant, it is preferred to fill the enclosure 39 with the hydraulic fluid and connect one or, preferably, two check valves 50 to the fluid lines 48 and 49 on opposite sides of the pump 47 so that additional hydraulic fluid can be admitted automatically to the system as required irrespective of which direction the pump is being run. In this manner, any hydraulic fluid that is lost as, for example, through seal leakage is immediately replenished.

By arranging a typical movable, but sealed, barrier such as a bellows or piston (neither shown) at a convenient point in a wall of the enclosure 39, the hydraulic fluid in the enclosure and the

chambers

45 and 46 will be maintained at a pressure at least equal to the hydrostatic pressure of fluids or so-called mud in the borehole 22. In this manner, by pressure-balancing the hydraulic system relative to the borehole hydrostatic pres sure, the hydraulic pump 47 needs only to develop a pressure suflicient to overcome the weight of the enclosure 39 and whatever friction there may be encountered in moving the cutting wheels 36 and enclosure.

Although other prime movers can be used, it is preferred to operate the pump 47 by a submersible reversible-type electric motor 51 of suitable dimensions to conveniently fit into the enclosure 39. Electrical conductors (not shown) are connected as required between the motor 51 and controls (not shown) in the upper housing 25 (FIGURE 1) for controlling the motor, with these conductors, of course, being fluidly sealed where they pass through the walls of the sealed enclosure 39.

To power the cutting wheels 36, the formation-sampling means 35 include a prime mover, preferably an electric motor 52, which is also fitted into the enclosure 39 and its shaft 53 connected to the cutting wheels 36 by suitable power-transmission means, such as a universal joint 54 which is connected by way of another shaft 55 to a right-angle gear drive 56 having outwardly diverging wheel shafts 57 at an angle to one another. It will be appreciated that by locating the cutting wheel motor 52 in the enclosure 39, it will also be pressure-balanced in the same manner as the pump motor 51. Similarly, as best seen in FIGURE 3, by enclosing the

shafts

53 and 55 and universal joint 54 in an oil-filled conduit, such as a tube 58 that is fluidly sealed at its opposite ends to the enclosure 39 and gear drive 56 and in fluid communication with each, the power transmission means will also be pressure-balanced.

A pair of depending arms 59 disposed on opposite sides of the protective tube 58 are connected at their lower ends to the gear drive 56 and pivotally connected at their upper ends to the enclosure 39 so as to pivot about an axis lying generally in the same horizontal plane as the pivotal axis of the universal joint 54. As part of the guide means 38, outwardly projecting guides, such as spring-biased keys or pins 60 (both seen in FIGURE 3), near the free ends of the pivoted arms 59 are slidably disposed in a labyrinth-like system of channels, such as slots or grooves 61 (only one system seen in FIGURE 2) that are formed in the interior side walls of the intermediate housing 27 on opposite sides of the longitudinal opening 37 therein. As will subsequently become apparent, these groove systems 61 are so arranged that upward longitudinal travel of the enclosure 39 from its full-line position to its dashed-line position at 62 in FIGURE 2 will 'be effective (through the coaction of the guides 60 in the groove systems) to direct the cutting wheels 36 along the path A-B-C-D depicted in FIGURES 2 and 4. Then, upon downward travel of the enclosure 39 back to the fullline position shown in FIGURE 2, the groove systems 61 and guides 60 will direct the cutting wheels 36 along the path D-A toward their initial position.

Turning now to FIGURE 4, a schematic representation is shown of one of the groove systems 61 arranged in accordance with the present invention. As seen there, the groove system 61 is arranged in a closed loop having two parallel

longitudinal portions

63 and 64 of unequal length and spaced apart from one another. The shorter grooves 63 are connected at their opposite ends to the longer grooves 64 by oppositely-directed

inclined grooves

65 and 66 which respectively intersect the longer grooves at longitudinally spaced intermediate points.

By directing the lower inclined grooves 65 upwardly and to the right (as viewed in FIGURES 2 and 4) toward the lower ends of the shorter longitudinal grooves 63, once the guide pins 60 are in the lower inclined grooves, upward travel of the enclosure 39 will carry the cutting wheels 36 outwardly and upwardly to their position shown generally at B. Similarly, by directing the upper inclined grooves 66 upwardly and to the left (as viewed in the drawings) from the upper ends of the shorter grooves 63 to the longer grooves 64, further upward travel of the enclosure 39 will move the cutting wheels 36 along their path B-C-D.

Accordingly, as the cutting wheels 36 move along the path A-B, they will be moving upwardly and outwardly as they cut their way into the formation 24. Then, as the cutting Wheels 36 move upwardly from their position at B to their position at C, they will be cutting along a straight path of a length determined by the vertical height of the shorter grooves 63. Upon reaching their position at C, the cutting wheels 36 will be retracted as they move further upwardly and cut their way toward their position at D. Thus, once the cutting wheels 36 have reached the position at D, a prismatic sample 23 with taperer ends will have been cut out of the formation 24 and, as later explained will fall through the housing opening 37 and drop into the core-receiving housing 29 therebelow.

From the foregoing description it will be realized that the groove systems 61 must be arranged to insure that the guide pins 60 are diverted into the lower inclined grooves 65 as the enclosure 39 moves upwardly. Similarly, when the enclosure "39 has reached its uppermost position (as at 62 in FIGURE 2), it is necessary that the guide pins 60 be prevented from re-entering the upper grooves 66 so that the cutting wheels 36 can proceed from their position at D back to their initial position at A. Otherwise, the cutting wheels 36 could return back along the path D-C-B which might require that they cut their way back through the formation 24 should the tool 20 have shifted slightly.

Accordingly, in accordance with the present invention, means are provided to direct the guide pins 66 in a predetermined direction around the circuitous groove systems 61 but prevent these pins from moving in the opposite direction. As seen in FIGURES 4 and 5, stop means, such as an abutment 67 having a downwardly facing abrupt surface 68, are provided in the lower end of each of the longer grooves 64 for preventing the guide pins 60 from entering the longer grooves as they move upwardly. To facilitate the passage of the guide pins 60, the abutment surfaces 68 are extended along the line of the downwardly facing wall of the lower inclined grooves 65 as shown in FIGURE 4.

A similar problem will, of course, exist at the upper ends of the groove systems 61. Once the cutting wheels 36 have reached their position as shown at D, means must be provided to insure that the guide pins will remain in the longer grooves 64 and not re-enter the upper end of the upper inclined grooves 66 as the enclosure 39 is returned downwardly. An abutment 69 having an abrupt surface 70 similar to that at 68 is, therefore, located across the entrance to the upper end of each of the upper inclined grooves 66. Here again, to facilitate the passage of the guide pins 60, the surfaces 70 are made as a continuation of the right-hand (as viewed in FIGURE 4) side walls of the longer grooves 64.

It will be recognized that the

abutments

67 and 69 must not, however, unduly hamper the passage of the guide pins 60 as they move in the correct directions around their respective groove systems 61. Thus, as best seen in FIG- URE 5, the height of each abutment, as at 67, is less than the total depth of its associated groove 64 and an inclined surface or ramp, as at 71, is provided from the bottom of the groove 64 up to the upper surface of the abutment, with this inclined surface being located ahead of the abrupt surface 68 in relation to the direction from which the guide pin 60 is intended to be coming. Thus, as the spring-biased guide pins 60 move downwardly in the grooves 64, for example, they will gradually retract as they move up the inclined ramps 71 of the abutments 67 as the enclosure 39 is moved downwardly. Once the guides 60 reach the abrupt surfaces 68, the springs 72 (FIGURE 3) will urge them outwardly to return them to their normal extended position. The inclined surfaces or ramps 73 (FIGURE 4) on the lower ends of the upper abutments 69 in the slots 63 will, of course, function in the same manner.

The arrangement of the

abutments

67 and 69 shown in FIGURE 4 will, therefore, positively direct the cutting wheels 36 along the path A-B whenever the enclosure 39 is moved upwardly. The abrupt surfaces 68 on the abutments 67 will, of course, prevent the guide pins 60 from continuing further upwardly in the longer grooves 64. Thus, once the guides 60 enter their respective lower inclined grooves 65, further upward travel of the enclosure 39 can only result in the cutting wheels 36 moving from their positions at B to their positions at D. Once the enclosure 39 has reached its upper limit of travel (as shown at 62 in FIGURE 2), the hydraulic pump 47 must, of course, be reversed to return the enclosure to its initial position. Upon downward travel, the guide pins 60 are, of course, prevented from re-entering the upper inclined grooves 66 by the abrupt surfaces 70 of the upper abutments 69.

Accordingly, with the groove systems 61 as shown in FIGURES 2 and 4, the core-slicing tool is capable of taking a formation sample 23 (FIGURE 1) having a height determined by the effective longitudinal length of the

grooves

65, 63 and 66. It is expected, of course, that the cutting wheels 36 will be capable of cutting the full distance through the formation 24. Ordinarily, therefore, for each trip that the cutting wheels 36 make, a single formation sample 23 will be obtained.

It will be appreciated, however, that on occasion malfunctions will occur in even the best of tools. Should, for example, the hydraulic pump 47 fail so that the enclosure 39 cannot be moved further upwardly, a normally-closed solenoid valve 74 (FIGURE 2) connected across the suction and discharge lines of the pump can be opened to equalize any pressure differential between the

hydraulic chambers

45 and 46. Once these pressures are equilized, the weight of the enclosure 39 will carry it and the cutting wheels 36 back downwardly to their initial positions. It will be realized that nothing in the

grooves

66, 63 and 65 will prevent reverse travel of the guide pins 60.

Similarly, should it be believed that for some reason the cutting means 36 were incapable of continuing upwardly, it would, of course, be necessary to reverse the travel of the enclosure 39 and return it and the cutting wheels 36 to their initial positions. This would, however, most likely leave a partially-cut formation sample that might not be recovered since the cutting wheels 36 would be returning along the previously-made kerfs in the formation 24. Thus, to avoid leaving a partially-cut sample, groove systems 61' as seen in FIGURE 6 and arranged in accordance with the present invention can be substituted for the systems 61.

As seen in FIGURE 6, these alternate groove systems 61' are identical to those systems 61 shown in FIGURES 2 and 4 except that an additional inclined groove 75 is provided to join the longitudinal grooves 63 and 64' at an intermediate point. Abutments 76 are provided in each of the shorter grooves 63 and arranged as shown in FIGURE 6 with upwardly facing abrupt surfaces 77 to divert the guide pins 60 back through the intermediate grooves 75 and on into the longer grooves 64 upon downward travel of the enclosure 39 once the guides reach the upper portions of the shorter grooves. In this manner, should, for example, the cutting means 36 be halted once the guides 60 are in the upper portions of the shorter grooves 63, reversal of the travel of the enclosure 39 will return the cutting wheels 36 to their retracted position by way of the intermediate grooves 75. Thus, at least a partial formation sample could be obtained. It will be realized, of course, that additional grooves (not shown) similar to the intermediate grooves 75 could be spaced between the grooves 63' and 64 if desired.

It will be noted in FIGURE 6 that abutments 78 are also included in the exits of the intermediate grooves 75 to the longer grooves 64'. Although these abutments 78 are not necessary to retract the cutting wheels 36, their abrupt surfaces 79 will prevent the guides 60 from moving from the longer grooves 64' into the shorter grooves 63 by way of the intermediate grooves 75 should the enclosure 39 inadvertently be moved upwardly with the guide pins still above the abutments 67 in the lower portion of the longer grooves 64.

There may well be situations where the cutting wheels 36 cannot be further advanced. As just described, the groove systems 61 in FIGURE 6 will enable the cutting wheels 36 to be returned along an alternate intermediate path to at least recover a partial sample. However, it must be realized that should the cutting wheels 36 be no longer operative, they cannot be returned along this alternate path. Accordingly, as seen in FIGURE 7, the guide pins 60 may be replaced with selectively retractable guide pins 60'. In this manner, should the guide pins 60 be above the abutment 76, solenoids 80 operatively connected to these pins can be retracted upon command from the surface to allow the weight of the enclosure 39 to carry the cutting wheels 36 back through their original kerfs along the path CB-A. It will be appreciated that retraction of the glide pins 60 will allow them to clear the abutments 76 and return back through the grooves 63 and The intermediate grooves in the groove systems 61 shown in FIGURE 6 permit a choice to be made after the tool 20 is in position as to whether a long or short formation sample is to be obtained depending upon the circumstances. However, it will be realized that a significant portion of a shorter sample could be damaged as the cutting wheels 36 are returned by their intermediate route. Accordingly, to permit some choice to be made in the length of a formation sample, a groove system 61" as partially shown in FIGURE 8 can be employed. This groove system 61" is generally similar to that shown at 61 in FIGURE 6 but has an upwardly inclined intermediate groove 81 instead. Removable barriers 82 are arranged as shown to be respectively mounted, as by screws 83, in either the entrance of the inclined grooves 81 (as indicated by the dashed lines) or in the shorter longitudinal grooves 63" just above these entrances to establish which of the two paths the guides 60 will follow. These barriers 82 must, of course, be positioned as desired before the tool 20 is placed in the borehole 22. To prevent the guides 60 from re-entering the inclined grooves 81 from the longer longitudinal grooves 64", abutments 84 similar to those already described are provided in the upper ends of these intermediate inclined grooves 81.

It will be noted in FIGURE 2 that the upper ends of the longer grooves 64 extend a considerable distance above the junction of these grooves with the upper inclined grooves 66. Although this extension of the longer grooves 64 is not required to guide the movements of the cutting wheels 36, the enclosure 39 itself is further stabilized by providing longitudinally spaced lateral guides (not shown) thereon adapted to remain at all times in these longer longitudinal grooves. These guides are always above the abutments 67 in the longer grooves 64 and will not, therefore, be prevented from moving either upwardly or downwardly in the grooves.

Turning now to FIGURE 9, the motion-translating means 87 of the present invention are shown. There, a cross-sectioned elevational view is shown of the

housings

28 and 29 coupled immediately below the intermediate tool housing 27. In the housing 28, the motion-translating means 87 are arranged for sequentially indexing a sample receiver 88 in the housing 29 therebelow into position to receive the formation samples, as at 23, as they are freed by the cutting means 36 and to segregate these samples from one another. Since the particular details of this sample receiver 88 are not essential to a full understanding of the present invention, suffice it to say that the receiver is basically comprised of a plurality of upright tubes 89 that are equally spaced about an axial shaft 90 journalled at its opposite ends in the housing 29, with these tubes being adapted to be successively rotated about the longitudinal axis of the housing into position to receive one of the formation samples 23. The upper ends of these tubes 89 are, of course, open and their lower ends are closed.

Accordingly, inasmuch as the sample-receiving tubes 89 are arranged to rotate about the longitudinal axis of the housing 29, the motion-translating means 87 seen in FIGURE 9 are arranged to rotate the sample-receiving tubes a predetermined increment of one revolution for each cycle of the cutting means 36. To accomplish this, the means 87 include an upright spindle 91 that is journalled at each end to the housing 28. To provide clearance for formation samples falling through the housing 28 into the sample receiver 88 therebelow, the spindle 91 is displaced laterally toward the rear of the housing. An upright tubular guide 92 is secured near the front of the housing 28, with its belled upper end 93 being arranged immediately below the place where it is expected that a formation sample 23 will enter the longitudinal housing opening 37 once the sample is out free.

The spindle 91 is provided with circuitous channel means such as a number of circumferentially spaced longitudinal grooves, as at 94, that are separated from one another by helical or slightly inclined grooves, as at 95, connected between the upper and lower ends of the longitudinal grooves. As seen in FIGURE 9, the bottom end of each of these helical grooves 95 opens into the lower portion of that one of the longitudinal grooves 94 immediately adjacent thereto on one side and the upper end of this same helical groove opens into the upper portion of that one of the longitudinal grooves immediately adjacent thereto but on the opposite side of the helical groove.

In this manner, the grooves 94 and 95'form a continuous, uninterrupted but alternating path completely around the circumference of the spindle 91. Thus, by beginning at a given point in any of the

grooves

94 or 95, a continuous path can be traced by following the alter nate changes in direction of the grooves around the spindle 91 and on back to the original starting point. Since four sample-receiving tubes 89 are employed with the preferred embodiment of the present invention, the

spindle 91 has four equally spaced longitudinal grooves 94 interposed between four equally spaced helical grooves 95, with each of the helical grooves connecting the bottom of one longitudinal groove to the top of the next adjacent longitudinal groove.

A spring-biased, laterally projecting guide pin or cam follower 96 is mounted on a sliding block 97 pivotally connected to the lower end of an actuating member 98, with the block being slidably mounted, as by a key and longitudinal slot arrangement 99 between the block and the interior of the rear Wall of the housing 28, for reciprocating longitudinal movement relative thereto. The free end of the spring-biased cam follower 96 is received in one of the

slots

94 or 95. Thus, as will be appreciated, longitudinal movement of the actuating member 98 will shift the cam follower 96 in a corresponding direction along the

grooves

94 and 95. Moreover, as the cam follower 96 is moved along one of the helical grooves 95, the spindle 91 will be rotated an amount corresponding to the lead of the helical grooves. Movement of the cam follower 96 along the longitudinal grooves 94 will, of course, produce no rotation of the spindle 91.

Accordingly, in the preferred embodiment of the present invention, the four sets of

grooves

94 and 95 will result in the spindle 91 being indexed or rotated for each cycle that the actuating member 98 is reciprocated. Although the reverse arrangement could be used, it is preferred to rotate the spindle 91 as the actuating member 98 is moved downwardly with respect to the housing 28. Thus, in a typical operation, the actuating member 98 is initially at its lower limit of travel and the cam follower 96 is near the bottom of one of the longitudinal grooves 94. As the enclosure 39 moves upwardly, a depending probe 100 secured to the enclosure and releasably coupled to the upper end of the actuating member 98 pulls the actuating member and sliding block 97 upwardly. The cam follower 96 is pulled upwardly by this motion along one of the longitudinal grooves 94.

By means to be subsequently described, the actuating member 98 is released from the probe 100 and latched in position to the housing 27 once the cam follower 96 reaches the upper end of the longitudinal groove 94 it is in at the moment so that the uncoupled probe can continue on upwardly along with the enclosure 39, Then, when the enclosure 39 returns toward its initial position (FIGURE 2), the depending probe 100 will again be coupled to the actuating member 98, release it from the housing 27, and return the member and sliding block 97 to their initial positions. As the actuating member 98 is first moved downwardly, the cam follower 96 will enter the upper end of the helical groove connected to the longitudinal groove 94 in which the cam follower was initially in. As the cam follower 96 moves downwardly in the helical groove 95, the spindle 91 is rotated an amount corresponding to the lead of the groove. Thus, once the cam follower 96 reaches the bottom of the helical groove 95 and enters the next longitudinal groove 94, the spindle 91 will have been indexed 90 from its original position. Rotation of the spindle 91, of course, produces a corresponding rotation of the sample-receiving tubes 88 so as to bring an empty tube into alignment With the bottom end of the guide tube 92.

It will be recognized that unless particular measures are taken, downward movement of the actuating member 98 would not necessarily result in the cam follower 96 returning to the bottom of the spindle 91 by way of the appropriate helical groove 95. Similarly, upward travel of the reciprocating actuating member 98 could just as well cause the cam follower 96 to move to the upper end of the spindle 91 by way of a helical groove 95 rather than a longitudinal groove 94.

Accordingly, of particular significance to the proper operation of the motion-translating means 87 of the present invention, abutment means are provided to insure that the cam follower 96 will always travel along a longitudinal groove 94 when moving upwardly and return downwardly through the next adjacent helical groove 95. To provide these abutment means, the bottom surface of each of the longitudinal grooves 94 is sloped upwardly from a maximum groove depth and radially outwardly to a minimum depth near the top of the groove that is still sufiicient to leave lateral side walls in the groove. On the other hand, the bottom surfaces of the helical grooves 95 are all sloped downwardly from a maximum groove depth and radially outwardly to a minimum depth near the bottom of the helical grooves that also leaves side walls in these grooves. As seen in FIGURE 9, these alternate groove arrangements will define abrupt surfaces, as at 101 and 102, at the upper and lower junctions of the

grooves

94 and 95 respectively.

In this manner, when the cam follower 96 is in the bottom of one of the longitudinal grooves 94, the abrupt surface 102 across the lower end of the associated helical groove 95 will prevent the cam follower from entering that helical groove and compel the cam follower to move up the ramp formed in the bottom of the longitudinal groove instead as the actuating member 98 is pulled upwardly. When the cam follower 96 passes the abrupt surface 101 in the upper end of the longitudinal groove 94 it is then in, the spring-biased follower will be urged into the deeper portion of the adjacent helical groove 95. Once the cam follower 96 passes the abrupt surface 101 at the upper end of these

connected grooves

94 and 95, it is prevented by this abrupt surface from re-entering the longitudinal groove 94 it just left. When the actuating member 98 is again moved downwardly, the cam follower 96 can, therefore, return to the bottom of the spindle 91 only by way of the helical groove 95 it is then in,

Accordingly, each complete cycle of reciprocation of the actuating member 98 will index the spindle 91 a partial revolution (90 in the preferred embodiment) and produce a corresponding rotation of the sample-receiving tubes 89. Thus, the motion-translating means 87 of the present invention will successively index each of the sample-receiving tubes 89 a predetermined portion of a revolution each time the cutting means 36 complete a full cycle of operation.

As previously mentioned, the actuating member 98 is detachably coupled to the depending probe 100 and, once released therefrom, is releasably latched to the housing 27 to hold the cam follower 96 at the top of its travel until the actuating member is again recoupled to the probe. To accomplish this, the opposed ends of the actuating member 98 and probe 100 are formed as shown in FIGURE 9 to provide a socket 103 in the lower end of the probe adapted to receive a complementarily shaped head 104 on the upper end of the actuating member. A hooked finger 105 depending from the lower end of the probe 100 along one side of the socket 103 is adapted for reception in a notch 106 on one side of the head 104. Thus, whenever the probe 100 is pulled upwardly by the enclosure 39, the hooked finger 105 will be co-engaged with the notched head 104 and pull the actuating member 98 upwardly along with it.

As the cam follower 96 approaches the upper limit of its travel with respect to the spindle 91, an inwardly projecting bowed spring 107 on the actuating member 98 engages the interior of a passage 108 in the housing 27 and urges the head 104 on the actuating member laterally outwardly. This outward movement of the actuating member 98 shifts the head 104 sufficiently to disengage the hooked finger 105 from the notch 106. Once the finger 105 clears the notch 106, the probe 100 will then be free to move on upwardly with the enclosure 39. To

hold the cam follower 96 at the top of its travel, as best.

seen in FIGURES 11 and 12, the outer corners of the actuating member 98 is notched, as at 109, with these notches being arranged to catch an inwardly directed 12 shoulder 110 on the housing 27. The spring 107 will at this time still be engaged with the inner surface of the passage 108 to maintain the actuating member 98 in this slightly inclined position.

Whenever the enclosure 39 again moves downwardly and the probe approaches the position shown in FIGURE 12, one face 111 of the socket 103 will engage the opposed face 112 of the head 104 to shift the actuating member 98 back over into its vertical position and, in so doing, disengage the notch 109 from the housing shoulder 110. Then, once the notch 109 is disengaged, the finger will again be engaged in the head notch 106 and the actuating member 98 will be moved downwardly relative to the spindle 91. This downward movement of the actuating member 98 will, of course, shift the cam follower 96 back down through one of the inclined spindle grooves 95 to rotate the spindle 91 a portion of a revolution and bring another sample-receiving tube 89 into alignment with the guide tube 92. For further details of the arrangement of the probe 100 and actuating member 98, attention is directed to a co-pending application Ser. No. 649,976 filed simultaneously herewith.

It will be recognized, of course, that it is desirable to have some indication at the surface of the progress of the cutting means 36 during the course of samplerecovering operation. Even though none of the

groove systems

61, 61 and 61", respectively depicted in FIGURES 4, 6 and 8, necessarily require that the exact position of the cutting means 36 be known at all times, such knowledge is nevertheless of obvious benefit to an operator at the surface.

Accordingly, as best seen in FIGURES 2 and 14, in one manner of providing indications at the surface representative of the longitudinal positions of the cutting means 36 in relation to the housing 27, an elongated tapered ramp 113 is secured to the housing in a convenient position that parallels the elongated rods 42. This tapered ramp 113 is suitably arranged to contact the outer end of a laterally movable actuator 114 that is connected to a variable electrical control 115 on the enclosure 39. As best seen in FIGURE 14, it is preferred to mount the control 115 within the enclosure 39 and extend the actuator 114 through a suitable fluid seal 116 in the enclosure wall.

Thus, at all longitudinal positions of the enclosure 39 in relation to the housing 27 and the tapered ramp 113, the actuator 114 will assume corresponding lateral positions that are directly related to the distance between the particular point where the actuator is in contact with the ramp and either end of the ramp. By selecting a potentiometer, for example, as the control 115, it will be recognized that the resistance between the moving contact and one end thereof will vary in accordance with the movement of its actuator 114, with this resistance being directly related to the longitudinal distance between the present position of the enclosure 39 and its initial position as shown in FIGURE 2. This resistance will, of course, be constantly varied as the enclosure 39 moves in either direction in relation to the housing 27.

Turning now to FIGURE 14, one arrangement is shown for mounting the control or potentiometer 115 within the enclosure 39. The potentiometer 115 is a typical fluidtight, so-called linear potentiometer which has a rectilinearily movable contact 117. To protect the potentiometer contact member 117 from damage, the potentiometer 115 is completely confined in the enclosure 39 and the actuator 114 movably disposed in a lateral bore 118 spaced from and parallel to the central axis of the potentiometer. As previously mentioned, the actuator 114 is fluidly sealed relative to the wall of the enclosure 39 by the fluid seal 116. The actuator 114 will, of course, be pressure-balanced since the pressure of the hydraulic fluid in the enclosure is maintained equal to that of the fluids in the borehole 22.

To operate the potentiometer 115, a rigid connecting 13 member 119 is disposed in an opening 120 between the bore 118 and the forward end of the potentiometer 115. The connecting member 119 is secured at its opposite ends to the actuator 114 and the distal end of the movable contact member 114 so that lateral movement of the actuator as it moves along the tapered ramp 113 will cause a corresponding movement of the contact member.

The varying resistance of the potentiometer 115' as the enclosure 39 moves could, of course, be measured directly at the surface to provide an indication of the present position of the cutting means 36 at any given time. It is preferred, however, to employ electronic means which provide a more reliable surface indication. Accordingly, a circuit 121 as seen in FIGURE 15 is employed in the present invention. Inasmuch as this circuit 121 is more fully explained in a copending application Ser. No. 649,978 filed concurrently with the present application, it is believed necessary only to describe this circuit only so far as to show its general relation to the present invention.

In general, therefore, the circuit 121 seen in FIGURE 15 is arranged to provide repetitive electrical pulses at the surface that have a pulse rate representative of the present longitudinal position of the cutting means 36 in relation to the housing 27. As the cutting means 36 change position in relation to the housing 27, the rate of these pulses will also change to provide a detectable indication at the surface characteristic of the new position of the cutting means.

To accomplish this, the fixed terminals of the potentiometer 115 are connected across a constant-voltage power supply 122 and its movable contact 117 is connected to the input of a typical so-called constant-current amplifier 123. This arrangement of the potentiometer 115 will, therefore, provide a voltage-divider circuit that has an output voltage directly related to the relative position of the movable potentiometer contact 117. Since the input impedance to amplifier 123 is constant, the current applied to its input will be directly related to the output voltage of the voltage-divider.

The current amplifier 123 desirably has a high output impedance so that the output current of the amplifier will be constant for any one position of the movable contact 117. Thus, as the input current to the amplifier 123 is varied by the potentiometer 115, the output current from the amplifier will vary accordingly, but will be constant for any single position of the movable contact 117. Thus, the magnitude of the output current from the amplifier 123 will at all times be directly related to the present position of the actuator 114 on the ramp 113.

A capacitor 124 connected across the output terminals of the amplifier 123 is charged by this output current, with the rate at which this capacitor is charged being, of course, directly proportional tothe magnitude of the output current from the amplifier. Thus, a high output current will charge the capacitor 124 at a faster rate than a lower output current.

The capacitor 124 and amplifier 123 are connected to the input of a typical voltage comparator 125. A reference voltage for the comparator 125 is derived from the constant-voltage power supply 122 by way of a pair of serially connected

resistors

126 and 127. The comparator 125 will generate a DC output signal whenever the input signal thereto equals the reference voltage. This DC output signal from the comparator 125 energizes a normallyopen gate 128 which is arranged to shunt the capacitor 124 through a resistor 129. The discharge rate of the capacitor 124 will thus be a function of the values of resistor 129 and the capacitor. The ouptut signal from the comparator 125 also energizes a normally-open gate 130 which then connects the junction between

resistors

126 and 127 through a relatively low-value resistor 131 to ground. Closing of the gate 130 will, therefore, decrease the reference voltage being applied to the comparator 125 due to the higher current passing through resistor 126. Thus, each time the voltage on the capacitor 124 reaches the initial reference voltage of the comparator 125, an output signal is developed by the comparator which continues until the capacitor has been discharged (by resistor 129) to reach a voltage equal to the now lower reference voltage of the comparator. At this time, the output signal of the comparator 125 ceases to re-open the

gates

128 and 130 thus restoring the reference voltage to its initial value.

It can be seen, therefore, that this intermittent operation Will produce pulses from the voltage comparator 125. The on time of these pulses is substantially related to the time required for the capacitor 124 to be discharged from a voltage equal to the high reference level initially applied to the comparator 125 to a voltage equal to the low reference level applied thereto. This time is, of course, a function of the capacitance of the compacitor 124, the resistance of resistor 129 and the difference between the high and low reference voltages. The off time of the pulses is, however, a function of the magnitude of current charging the capacitor 124. Thus, it can be seen that the frequency or pulse rate of the pulses will be proportional to the output current from the amplifier 123 and, therefore, to the several positions of the movable contact 117.

The pulse rate will, therefore, depend upon how rapidly the capacitor 124 is charged. In one position of the actuator 114 on the ramp 113, the output current of the amplifier 123 will be relatively low and the capacitor 124 will be correspondingly slow in charging to a level sufficient to initiate the aforementioned operation of the comparator 125. On the other hand, when the actuator 114 moves to a different position on the ramp 113, the resulting higher output current of the amplifier 123 will more quickly charge the capacitor 124 and, as a result, actuate the comparator 125 sooner than before.

The string of output pulses from the comparator 125 are transmitted through the suspension cable 21 to a suitable pulse-rate detector 132 at the surface. The varying DC output of the pulserate detector 132 is connected to an indicator, such as a voltmeter 133, which is suitably calibrated to provide an indication of the present position of the cutting means 36. Thus, in the operation of the present invention, when the cutting means 36 are in one position, the pulse output of the voltage comparator 125 will be at a rate characteristic of this position. As the cutting means 36 move up or down, this pulse rate will correspondingly change to provide a different indication on the position indicator 133 at the surface.

It will be appreciated that other position-establishing means can be employed instead of the potentiometer 115 and tapered ramp 113. For example, as schematically represented in FIGURE 16, the tapered ramp 113 and potentiometer 115 can be replaced by the position-establishing means 134 shown there. In general, the positionestablishing means 134 are comprised of an elongated rod 135 secured at each end to the housing 27 and arranged parallel to the elongated rods 42 exterior of the enclosure 39. For reasons that will subsequently become apparent, the rod 135 has a lower portion 136 and an upper portion 137 joined in tandem, with each portion being of a material with different magnetic properties. For example, in one embodiment of the present invention, the lower rod portion 136 was made of a stainless steel having a significantly dififerent permeability than that of the upper portion 137 which was made of low-carbon steel. The

rod portions

136 and 137 are joined, as at 138, at a point that is preferably about even with the top of the enclosure 39' when it is in its lowermost position.

A variable-differential transformer 139 having one winding with equal but

opposed portions

140 and 141 and another winding 142 operatively arranged therewith is disposed around the elongated rod 135 and secured to the enclosure 39'. Thus, as the enclosure 39 is moved upwardly in relation to the housing 27', the transformer 139 is moved a corresponding amount in relation to the core rod 135. It will be understood, therefore, that as the upper rod portion 137 enters the transformer 139, the mutual coupling of the transformer will be correspondingly changed. This change of mutual coupling will, of course, be directly related to the distance that the enclosure 39 moves from its lowermost position.

In one manner of coupling the position-establishing means 134 to the circuit 121, one winding of the transformer 139 is connected to a source of AC voltage (not shown) and the other winding connected by way of rectifiers (not shown) across the input terminals of the constant-current amplifier 123 instead of the potentiometer 115. Thus, the movement of the transformer 139 in relation to the core rod 135 will be translated to the position indicator 133 at the surface. It will be recognized, of course, that the same principle can also be employed to vary other electrical circuits as, for example, the frequency of a signal generator (not shown).

Turning now to the operation of the present invention, the core-slicing tool is first brought into position opposite a formation, as at 24, from which a sample is desired. Once the tool 20 is in position, the wall-engaging member 31 is extended to urge the forward face of the tool against the opposite wall of the borehole 22. As best seen in FIGURE 2, the

motors

51 and 52 are then started and, once hydraulic pressure is applied to the upper chambers 45, the enclosure 39 will move upwardly in relation to the now-fixed housing 27. As previously described with reference to, for example, the groove system 61, the cutting wheels 36 will be progressively moved upwardly through their various positions A BCD as the enclosure 39 moves toward its dotted-line position 62 shown in FIGURE 2.

It will be recalled, of course, that the cam follower 96 is at this time moving upwardly through one of the longitudinal spindle grooves 94 until being latched to the housing 27 so that no rotation is imparted to the samplereceiving tubes 89. Once the position indicator 133 indicates that the enclosure 39 is in its uppermost position, it will be assumed that a formation sample, such as at 23, has been cut and has fallen through the opening 37 and guide tube 92 into the sample-receiving tube 89 then in alignment with the guide tube.

When the enclosure 39 is at its uppermost position 62, the pump motor 51 is reversed to relieve the pressure in the upper hydraulic chamber 45 and allow the enclosure to return downwardly to its initial position. The position indicator 133 will, of course, serve as a monitor to observe the progress of the enclosure 39. As the enclosure 39 nears its lowermost position, the depending probe 100 thereon will release the actuating member 98 from the housing 27 and then move the actuating member downwardly in relation to the spindle 91. This downward movement of the actuating member 98 will, of course, carry the cam follower 96 back down through one of the helical spindle grooves 95 and thereby rotate the sample-receiving tubes 90. Once the enclosure 39 has reached its lowermost position, another sample-receiving tube 89 will be aligned with the guide tube 92 for reception of another formation sample.

If more than one formation sample is desired, the wallengaging member 31 is retracted and the core-slicing tool 20 moved to another position in the borehole 22. Then, once the wall-engaging member 31 is again extended, the above-described procedure is repeated. Whenever a sufficient number of formation samples 23 are obtained, the tool 20 is then returned to the surface.

Accordingly, it will be appreciated that the present invention has provided a new and improved means for controlling the operation of a core-slicing tool capable of obtaining a plurality of formation samples from earth formations of interest. Moreover, by arranging the tool of the present invention with the various guide systems described herein, the cutting means will be positively 16 guided and controlled at all times. Similarly, the motiontranslating means of the present invention enable movement of the core-slicing tool to position a sample receiver to receive each sample and segregate it from the others in a predetermined location for later identification.

While particular embodiments of the present invention have been shown and described, it is apparent that changes and modifications be made without departing from this invention is its broader aspects; and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What is claimed is:

1. Apparatus for obtaining samples of earth formations traversed by a borehole comprising: a support adapted for suspension in a borehole; formation-sampling means on said support and adapted for travel relative thereto between longitudinally-spaced positions; guide means for directing said formation-sampling means along one path whenever said formation-sampling means travels in one direction in relation to said support and for directing said formation-sampling means along a different path whenever said formation-sampling means travels in the opposite direction in relation to said support; and means for moving said formation-sampling means along said paths.

2. The apparatus of claim 1 further including: means for collecting formation samples obtained by said formation-sampling means.

3. Apparatus for obtaining samples of earth formations traversed by a borehole comprising: a support adapted for suspension in a borehole; formation-sampling means on said support and adapted for travel relative thereto between longitudinally-spaced positions, said formation-sampling means including formation-cutting means adapted, when extended, to penetrate a borehole wall at transversely spaced points and make at least a substantial intersection in an earth formation; means for moving said formation-sampling means from one of said spaced positions to the other of said spaced positions and then returning said formation-sampling means to said one spaced position; and guide means for selectively moving said cutting means laterally in relation to said support from a retracted position to an extended position as said formation-sampling means are moved toward said other spaced position and for retaining said cutting means in said retracted position as said formation-sampling means are moved from said other spaced position toward said one spaced position.

4. The apparatus of claim 3 further including: electrical means responsive to positioning of said formationsampling means relative to said support for providing indications at the surface representative of the longitudinal positions of said formation-sampling means in relation to said support.

5. The apparatus of claim 4 wherein said electrical means include: transformer means including elongated core portion having distinguishable variations of magnetic properties at predetermined intervals of its length and winding portions operatively disposed in relation to said core portion; first means securing one of said transformer means portions between longitudinally-spaced positions on said support; and second means securing the other of said transformer means portions between lon gitudinally-spaced positions on said formation-sampling means for longitudinal travel relative to said one trans former means portion to provide varying electrical indications representative of the longitudinal position of said other transformer means portion relative to said one transformer means portion.

6. The apparatus of claim 3 wherein said guide means are responsive to travel of said formation-sampling means from said one spaced position toward said other spaced position to successively move said cutting means from said retracted position to said extended position and then back to said retracted position.

7. The apparatus of claim 6 wherein said guide means further include: means for alternatively returning said cutting means to said retracted position before said formation-sampling means have reached said other position.

8. The apparatus of claim 7 wherein said means for alternatively returning said cutting means to said retracted position are selectively operable from the surface.

9. The apparatus of claim 3 further including: means for collecting formation samples obtained by said formation-sampling means.

10. The apparatus of claim 9 wherein said sample-collecting means include means responsive to travel of said formation-sampling means for operating said sample-collecting means to segregate individual formation samples.

11. The apparatus of claim 9 wherein said sample-collecting means include: separate compartments respectively adapted to receive a formation sample; means supporting said compartments for successive movement of each of said compartments from an inactive position to a position for reception of a formation sample; and motiontranslating means for successively moving said compartments one at a time into position to receive a formation sample in response to travel of said formation-sampling means between said spaced positions.

12. The apparatus of claim 11 wherein said motiontranslating means are responsive only to travel of said formation-sampling means in one direction between said spaced positions.

13. The apparatus of claim 9 wherein said samplecollecting means include: separate compartments respectively adapted to receive a formation sample; means rotatably supporting said compartments for rotation about a longitudinal axis from an inactive position to a position for reception of a formation sample; and motion-translating means for successively rotating said compartments one at a time into position to receive a formation sample in response to repeated travel of said formation-sampling means between said positions.

14. The apparatus of claim 13 wherein said motiontranslating means include: a shaft operatively journalled for rotation about a longitudinal axis; said shaft having a plurality of longitudinal channels spaced thereabout and a plurality of inclined channels respectively interspersed between adjacent ones of said longitudinal channel with the upper end of each inclined channel opening into the upper portion of the longitudinal channel on one side thereof and the lower end of each inclined channelopening into the lower portion of the longitudinal channel on the other side thereof so as to define a continuous alternating path around the circumference of said shaft; cam means adapted for reciprocating movement relative to said shaft and along said channels; first means between said cam means and said formation-sampling means for reciprocating said cam means along said channels as said formation-sampling means travel between said spaced positions to rotate said shaft whenever said cam means are moved along one of said inclined channels; and second means connecting said shaft to said rotatable support means for rotating said compartments whenever said shaft is rotated.

15. The apparatus of claim 14 further including: first abutment means in each of said longitudinal channels for preventing said cam means from moving in a predetermined direction therein without limiting movement therein of said cam means in the reverse direction; and second abutment means in each of said inclined channels for preventing said cam means from moving in said reverse direction therein without limiting movement therein of said cam means in said predetermined direction.

16. Apparatus for obtaining samples of earth formations traversed by a borehole comprising: a support adapted for suspension from a cable in a borehole; formation-sampling means including motive means on said support and adapted for travel relative thereto in opposite directions between longitudinally-spaced positions, first and second cutting wheels respectively arranged in converging substantially vertical planes having an intersection to one side of said support, means supporting said cutting wheels for lateral movement in relation to said support from a retracted position to an extended position along said one side of said support, and power-transmission means operatively connecting said motive means to said cutting wheels; means selectively operable from the surface for moving said formation-sampling means in one direction from a first of said spaced positions to a second of said spaced positions and then returning said formation-sampling means in the opposite direction to said first spaced position; and guide means operatively arranged between said support and said cutting wheels and responsive to travel of said formation-sampling means in said one direction to successively move said cutting wheels from said retracted position to said extended position and then return said cutting wheels to said retracted position by the time that said formation-sampling means have reached said second position, said guide means being further responsive to travel of said formation-sampling means in said other direction to retain said cutting wheels in said retracted position.

17. The apparatus of claim 16 further including: electrical means responsive to said travel of said formationsampling means for providing indications at the surface representative of the longitudinal positions of said cutting wheels in relation to said support.

18. The apparatus of claim 17 wherein said electrical means include: transformer means including elongated core portion having distinguishable variations of magnetic properties at predetermined intervals of its length and winding portions operatively disposed in relation to said core portion; first means securing one of said transformer means portions between longitudinally-spaced positions on said support; and second means securing the other of said transformer means portions between longitudinally-spaced positions on said formation-sampling means for longitudinal travel relative to said one transformer means portion to provide varying electrical indications representative of the longitudinal position of said other transformer means portion relative to said one transformer means portion.

19. The apparatus of claim 16 wherein said guide means includetfirst and second longitudinal channels spaced from one another on said support and facing said formation-sampling means, said second longitudinal channel being between said first longitudinal channel and said one side of said support; first and second transverse channels spaced from one another on said support and facing said formation-sampling means, one of said transverse channels interconnecting adjacent lower portions of said longitudinal channels and the other of said transverse channels interconnecting adjacent upper portions of said longitudinal channels; and a laterally-projecting guide member having a distal portion adapted for reception in said channels and operatively connected to said cutting wheels for moving said cutting wheels laterally between their said positions as determined by the relative spacings of said channels.

20. The apparatus of claim 19 wherein said guide means further include: abutment means for guiding said guide member out of said first longitudinal channel and into said first transverse channel whenever said formation-sampling means are moved in said one direction without preventing movement of said guide member along said first longitudinal channel whenever said formation-sampling means are moved in said other direction.

21. The apparatus of claim 19 wherein said guide means further include: abutment means for preventing said guide member from leaving said first longitudinal channel and entering said first transverse channel whenever said formation-sampling means are moved in said other direction without preventing said guide member from moving along said first-transverse channel and entering said first longitudinal channel whenever said formation-sampling means are moved in said one direction.

22. The apparatus of claim 19 wherein said guide means further include: first abutment means for guiding said guide member out of said first longitudinal channel and into said first transverse channel whenever said formationsampling means are moved in said one direction; and second abutment means for preventing said guide member from re-entering said second transverse channel after reentering said first longitudinal channel from said second transverse channel whenever said formation-sampling means are moved in said other direction.

23. The apparatus of claim 19 wherein said guide means further include: first abutment means for guiding said guide member out of said first longitudinal channel and into said first transverse channel whenever said formation-sampling means are moved in said one direction without preventing said guide member from moving along said first longitudinal channel whenever said formation-sampling means are moved in said other direction; and second abutment means for preventing said guide member from re-entering said second transverse channel after reentering said first longitudinal channel whenever said formation-sampling means are moved in said other direction without preventing said guide member from moving along said second transverse channel and re-entering said first longitudinal channel whenever said formation-sampling means are moved in said one direction.

24. The apparatus of claim 23 wherein said guide means further include: a third transverse channel intermediate of said first and second transverse channels and interconnecting intermediate portions of said first and second longitudinal channels to provide an alternative path for said guide member to re-enter said first longitudinal channel after entering said second longitudinal channel; and third abutment means selectively positionable in either said third transverse channel or in an intermediate portion of said second longitudinal channel to determine which of the two last-mentioned channels said guide member will enter as said formation-sampling means are moved in said one direction.

25. The apparatus of claim 23 wherein said guide means further include: a third transverse channel intermediate of said first and second transverse channels and interconnecting intermediate portions of said first and second longitudinal channels to provide an alternative path for said guide member to re-enter said first longitudinal channel after entering said second longitudinal channel; and third abutment means for guiding said guide member out of said second longitudinal channel and into said third transverse channel whenever said formation-sampling means are moved in said other direction without preventing said guide member from moving along said second longitudinal channel Whenever said formation-sampling means are moved in said one direction.

26. The apparatus of claim 16 further including: means for collecting formation samples obtained by said cutting wheels including a plurality of compartments respectively adapted to receive a formation sample, means rotatably supporting said compartments for rotation about a longitudinal axis from an inactive position to a position for reception of a formation sample, and motion-translating means for successively rotating said compartments one at a time into position to receive a formation sample in response to repeated travel of said formation-sampling means between said positions.

27. The apparatus of claim 26 wherein said motiontranslating means are responsive only to travel of said formation-sampling means in one direction between said spaced positions.

28. The apparatus of claim 26 further including: electrical means responsive to said travel of said formationsampling means for providing indications at the surface representative of the longitudinal positions of said cutting wheels in relation to said support.

29. The apparatus of claim 28 wherein said electrical means include: transformer means including elongated core portion having distinguishable variations of magnetic properties at predetermined intervals of its length and winding portions operatively disposed in relation to said core portion; first means securing one of said transformer means portions between longitudinally-spaced positions on said support; and second means securing the other of said transformer means portions between longitudinallyspaced positions on said formation-sampling means for longitudinal travel relative to said one transformer means portion to provide varying electrical indications representative of the longitudinal position of said other transformer means portion relative to said one transformer means portion.

30. The apparatus of claim 26 wherein said motiontranslating means include: a shaft operatively journalled for rotation about a longitudinal axis; said shaft having a plurality of longitudinal channels spaced thereabout and a plurality of inclined channels respectively interspersed between adjacent ones of said longitudinal channels with the upper end of each inclined channel opening into the upper portion of the longitudinal channel on one side thereof and the lower end of each inclined channel opening into the lower portion of the longitudinal channel on the other side thereof so as to define a continuous alternating path around the circumference of said shaft; cam means adapted for reciprocating movement relative to said shaft and along said channels; first means between said cam means and said formation-sampling means for reciprocating said cam means along said channels as said formation-sampling means travel between said spaced positions to rotate said shaft whenever said cam means are moved along one of said inclined channels; and second means connecting said shaft to said rotatable support means for rotating said compartments whenever said shaft is rotated.

31. The apparatus of claim 30 further including: first abutment means in each of said longitudinal channels for preventing said cam means from moving in a predetermined direction therein without limiting movement therein of said cam means in the reverse direction; and second abutment means in each of said inclined channels for preventing said cam means for moving in said reverse direction therein without limiting movement therein of said cam means in said predetermined direction.

32. The apparatus of claim 26 wherein said guide means include: first and second longitudinal channels spaced from one another on said support and facing said formation-sampling means, said second longitudinal support channel being between said first longitudinal support channel and said one side of said support; first and second transverse channels spaced from one another on said support and facing said formation-sampling means, one of said transverse channels interconnecting adjacent lower portions of said longitudinal support channels and the other of said transverse channels interconnecting adjacent upper portions of said longitudinal support channels; and a laterally-projecting guide member having a distal portion adapted for reception in said support channels and operatively connected to said cutting wheels for moving said cutting wheels laterally between their said positions as determined by the relative spacings of said support channels.

33. The apparatus of claim 32 wherein said guide means further include: abutment means for guiding said guide member out of said first longitudinal support channel and into said first transverse channel whenever said formation-sampling means are moved in said one direction without preventing movement of said guide member along said first longitudinal support channel whenever said formation-sampling means are moved in said other direction.

34. The apparatus of claim 32 wherein said guide means further include: abutment means for preventing said guide member from leaving said first longitudinal support channel and entering said first transverse channel Whenever said formation-sampling means are moved in said other direction without preventing said guide member from moving along said first-transverse channel and entering said first longitudinal support channel whenever said formation-sampling means are moved in said one direction.

35. The apparatus of claim 32 wherein said guide means further include: first abutment means for guiding said guide member out of said first longitudinal support channel and into said first transverse channel whenever said formation-sampling means are moved in said one direction; and second abutment means for preventing said guide member from re-entering said second transverse channel after re-entering said first longitudinal support channel from said second transverse channel whenever said formation-sampling means are moved in said other direction.

36. The apparatus of claim 32 wherein said guide means further include: first abutment means for guiding said guide member out of said first longitudinal support channel and into said first transverse channel whenever said formation-sampling means are moved in said one direction without preventing said guide member from moving along said first longitudinal support channel whenever said formation-sampling means are moved in said other direction; and second abutment means for preventing said guide member from re-entering said second transverse channel after re-entering said first longitudinal support channel whenever said formation-sampling means are moved in said other direction without preventing said guide member from moving along said second transverse channel and re-entering said first longitudinal support channel whenever said formation-sampling means are moved in said one direction.

37. A well tool comprising: a support adapted for reception in a well bore; first means adapted for reciprocating movement between longitudinally-spaced positions on said support; second means operatively connected to said first means and adapted for lateral movement in relation to said support between retracted and extended positions; guide means operatively arranged between said support and said second means for successively moving said second means from said retracted position to said extended position and then back to said retracted position Whenever said first means are moved relative to said support from one of said spaced positions to another of said spaced positions and then retaining said second means in said retracted position whenever said first means are moved relative to said support from said other spaced position to said one spaced position; third means adapted for rotation in relation to said support about a longitudinal axis; and motion-translating means operatively connected between said first and third means for rotating said third means in response to reciprocating movement of said first means.

38. The well tool of claim 37 wherein said motiontranslating means are operative only in response to movement of said first means in one longitudinal direction.

39. The well tool of claim 37 wherein said guide means include: first and second longitudinal channels spaced from one another on said support and facing said second means; first and second transverse channels spaced from one another on said support and facing said second means, one of said transverse channels interconnecting adjacent lower portions of said longitudinal channels and the other of said transverse channels interconnecting adjacent upper portions of said longitudinal channels; and a laterally-projecting guide member having a distal portion adapted for reception in said channels and operatively connected to said second means for moving said second means laterally between their said positions as determined by the relative spacings of said channels.

40. The well tool of claim 39 wherein said guide means further include: abutment means for guiding said guide member out of said first longitudinal channels and into said first transverse channel whenever said first means are moved in one direction without preventing movement of said guide member along said first longitudinal channel whenever said first means are moved in the opposite direction.

41. The well tool of claim 39 wherein said guide means further include: abut-ment means for preventing said guide member from leaving said first longitudinal channel and entering said first transverse channel whenever said first means are moved in one direction without preventing said guide member from moving along said first-transverse channel and entering said first longitudinal channel whenever said first means are moved in the opposite direction.

42. The Well tool of claim 39 wherein said guide mean further include: first abutment means for guiding said guide member out of said first longitudinal channel and into said first transverse channel whenever said first means are moved in one direction; and second abutment means for preventing said guide member from re-entering said second transverse channel after re-entering said first longitudinal channel from said second transverse channel whenever said first means are moved in the opposite direction.

43. The well tool of claim 39 wherein said guide means further include: first abutment means for guiding said guide member out of said first longitudinal channel and into said first transverse channel whenever said first means are moved in one direction without preventing said guide member from moving along said first longitudinal channel whenever said first means are moved in the opposite direction; and second abutment means for preventing said guide member from re-entering said second transverse channel after re-entering said first longitudinal channel whenever said first means are moved in said opposite direction without preventing said guide member from moving along said second transverse channel and reentering said first longitudinal channel whenever said first means are moved in said one direction.

44. The well tool of claim 43 wherein said guide means further include: a third transverse channel intermediate of said first and second transverse channels and interconnecting intermediate portions of said first and second longitudinal channels to provide an alternative path for said guide member to re-enter said first longitudinal channel after entering said second longitudinal channel; and third abutment means selectively positionable in either said third transverse channel or in an intermediate portion of said second longitudinal channel to determine which of the two last-mentioned channels said guide member will enter as said first means are moved in said one direction.

References Cited UNITED STATES PATENTS 1,599,140 9/1926 Mason 58 X 2,327,023 8/1943 Danner 17578 X 2,599,405 6/1952 Mennecier 175-78 X 2,896,913 7/1959 Holmes et a1. 17578 X 3,173,500 3/1965 Stuart et al 175-78 X 3,225,828 12/1965 Wisenbaker et al. 16655 3,353,612 11/1967 Bannister 175-58 X DAVID H. BROWN, Primary Examiner.

U.S. Cl. X.R.