Wire line core barrel apparatus

Aug. 19, 1969

Filed April 30, 1968

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R. K. CASPER ET AL 3,461,981

WIRE LINE CORE BARREL APPARATUS . 2 Sheets-Sheet 1

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KAY X. CASPXK REBIRT A. AWW jrrowaYS

Aug. 19, 1969 r κ. casper et al 3,461,981

WIRE LINE CORE BARREL APPARATUS

Filed April 30, 1968 ² Sheets-Sheet 2

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3,461,981

Patented Aug. 19, 1969

United States Patent Office . 3,461,981

WIRE LINE CORE BARREL APPARATUS

Ray K. Casper and Albert L. Linn, Minneapolis, Minn., assignors to E. J. Longyear Company, Minneapolis, Minn., a corporation of Delaware

Filed Apr. 30,1968, Ser. No. 725,399

Int. Cl. E21b 9/20, 25/00

U.S. Cl. 175—246 7 Claims

ABSTRACT OF THE DISCLOSURE

Core barrel apparatus that includes a drill stem having an annular core bit, a landing ring and a latch seat, and a core barrel inner tube assembly having a landing ring mounted on a latch body for abutting against the drill stem landing ring to support said assembly, said latch body having grooves for bypassing drilling fluid in the area adjacent the landing rings, an inner tube, two separate third tube sections in the inner tube, and a stop ring and a plunger for retaining the tube sections in place on the inner tube.

Background of the invention

Core barrel apparatus having an outer tube, a core barrel inner tube and an axially split third tube retained in the inner tube for facilitating the taking of soft and broken core. In prior art apparatus such as U.S. Patents 3,120,282, 3,120,283 and 3,333,647. when used.for drilling cores of soft material or fragmented material there is a problem of removing the drilled core from the inner tube and at the same time retaining the parts of the core in the relative positions as drilled from the earth formation. Additionally a problem of a similar nature as that above mentioned as’ well as other problems are encountered in using” structures such as disclosed in U.S. Patent 2^073,^876 which discloses an outer tu$e,' an inner tube and a non split’third tube haying a major portion thereof located in the inner tube. In order to solve problems of the above mentioned nature as well as other problems, this invention has been made.

Summary of the invention

The invention is directed to providing an axially split third tube in a core barrel inner tube assembly to facilitate taking samples of broken and soft cores and the mounting of the third tube in a manner that it may be readily removed from the inner tube. Other features of the invention include the provision of readily replaceable landing rings on the core barrel outer tube assembly and the core barrel inner tube assembly arid grooved fluid bypass channels in the latch body adjacent the core barrel inner tube assembly landing ring. . .. .

In order that the invention. described herein , may be more fully understood,: the,meaning of certain terminology as used in the specification.will be set forth.,The term “inner” refers to that portion of the drill stem or an element of an assembly in its position “fpr use” in .the,drill stem which is located axially closer to the bit. attached to the drill stem than any other portion of the drill stem or elements being referred to, except where the term refers to the transverse circumference, or the peripheral surface or the diameter of the drill stem of said elements. The term “outer” refers to that portion of the drill stem or. of an element in its “position for use” in the drill stem which is located axially closer to the mouth of the drill hole than the other portion of the drill stem or element being referred to except where the term refers to a transverse circumference or the peripheral surface or the diameter of an element or the drill stem.

Brief description of the drawings

FIGURES 1 and 2 when arranged one above the other, with the center line aligned with FIGURE 1 at the top and FIGURE 2 at the bottom, form a composite longitudinal section through the core barrel inner tube assembly and the drill stem, said assembly being shown in a latched core receiving position. The meeting line between FIGURE 1 (top) and FIGURE 2 (below) is at the line A—A;

FIGURE 3 is a somewhat enlarged, transverse cross sectional view generally taken along the line and in the direction of the arrows 3—3 of FIGURE 1 to illustrate the mounting of. the latches;

FIGURE 4 is a somewhat enlarged, transverse cross sectional view, generally taken along the line and in the direction of the arrows 4—4 of FIGURE 1 to in part illustrate the fluid bypass channels of a core barrel inner tube assembly;

. FIGURE 5 is a somewhat enlarged, transverse cross sectional view generally taken along the line and in the direction of the arrows 5—-5 of FIGURE 2 to illustrate the upper end portion of the core barrel inner tube and the structure located therein;

FIGURE 6 is an enlarged, fragmentary transverse cross sectional view generally taken along the line and in the direction of the arrows 6—6 of FIGURE 2 to illustrate the fluid bypass channels adjacent the core lifter case;

FIGURE 7 is an enlarged fragmentary longitudinal view, part in cross section, to illustrate the relative positions of the stop ring and the split tube liner; and in part of the fluid bypass channel adjacent the core lifter case; and

FIGURE 8 is a longitudinal cross sectional view, part in schematic, illustrating forcing the split tube liner out of the core barrel inner tube.

Referring now in particular to FIGURES 1 and 2, there is illustrated a hollow drill stem 10 which is made up of sections of pipe coupled together and having an annular drill bit 11 mounted on the inner end thereof. Even though the longitudinal axis of the drill stem as illustrated in FIGURES 1-2 is shown extending in a horizontal direction, it is to be understood that this is for purposes of illustration only; and that, the apparatus of this invention is for use not only when the direction of drilling is generally downwardly such that the angle of drilling direction is not inclined from the vertical in an amount greater than which the core barrel inner tube assembly, generally designated 15,. will free, fall of the drill stem; but also where the latch body release tube and a spear point plug are of a modified construction so that the core barrel inner tube assembly is fluidly propellable to the bit end of the drill regardless of the drilling direction

3,461,981 such as disclosed in U.S. Patent No. 3,120,282, issued Feb. 4, 1964, U.S. Patent No. 3,120,283, issued Feb. 4, 1964, and U.S. Patent No. 3,333,647, issued Aug. 1, 1967. The portion of the drill stem attached to or extending below pipe section 10α is commonly referred to as a core barrel outer tube assembly, generally designated 12; the core barrel outer tube assembly being provided for receiving and retaining the core barrel inner tube assembly 15. Details of construction of the core barrel outer tube assembly of the general nature used in this invention are set forth in the aforementioned patents, however, as will become more apparent hereinafter, the construction of portions of the assembly 12 is different from that described in one or more of the aforementioned patents. The core barrel outer tube assembly 12 is composed of a core barrel outer tube 18, a reaming shell 19 threadedly connected to the inner end of the tube 18, said shell having hardened material such as diamonds, not shown, on the transverse outer reaming surface and an annular core bit 11 for drilling into the earth formation from which the core sample is taken, said bit being threadedly connected to the inner end of the reaming shell. The outer end of the assembly 12 includes a locking coupling 20 which connects one end of the assembly 12 to the adjacent pipe section 10α of the drill stem. The opposite ends of the coupling 20 is connected to an adapter coupling 21 which is provided with hardened lands 22. The lower end of the locking coupling in conjunction with the annular recess 21α of the adapter coupling forms a latch seat inside the surface of the adapter coupling against which the latches (detents) 16, 17 of the core barrel inner tube assembly are seated for removably retaining the assembly 15 adjacent the core bit. Also, the lower end portion of the locking coupling has a projection flange 20a that extends as a partial cylindrical surface to bear against a face of a latch and cause the latch and other portions of the core barrel inner tube assembly to rotate with the drill stem when the latches are in a latch seated position such as indicated in FIGURE 1.

Threadedly connected to the inner end of the adapter coupling is the outer end of the core barrel outer tube 18, the core barrel outer tube having an annular recess 18α to receivingly mount a landing ring 23 in abutting engagement with the adapter coupling (see FIGURE 1). As may be noted, the inner diameter of the landing ring is sufficiently smaller than the inner diameter of the remaining portion of the drill stem that is axially outwardly of the core bit to form a suspension shoulder in the core barrel outer tube.

Not previously mentioned is that the reaming shell and the core bit cooperatively provide an annular recess Ila for seating a stabilizer ring 14 in position to aid in retaining the core barrel inner tube assembly 15 in a centralized condition relative the inner end of the core barrel outer tube assembly. Ring 14 has an annular casing 14α and circumferentially spaced, axially elongated teeth 14b that extend radially outwardly of the casing. Since the axial length of the casing is less than that of the teeth, there is provided a fluid flow path radially between the casing and the core bit to permit the majority of drilling fluid to bypass the adjacent portion of the core barrel inner tube assembly; while the inner diameter of the casing is slightly larger than the outer diameter of the adjacent part of the core barrel inner tube assembly to permit a small amount of fluid bypass between the casing and the core barrel inner tube assembly.

The core barrel inner tube assembly 15 includes a latch body 26 having a pair of detents or latches 16, 17 and a latch insert block 25 mounted thereon, a latch release tube 27 for retracting said latches, an inner tube cap 29 threaded onto the outer end of a core receiving tube 28, and a spindle 30 for connecting the cap to the inner end portion of the latch body for limited relative slidable movement. A bearing 32 is mounted on the spindle in abutting engagement with the inner end of the bearing housing 33 which is also slidably mounted onto the spindle and threadedly connected to cap 29; there being provided a coil spring 34 that at one end abuts against said bearing and at the opposite end against a spring retaining washer 31 which in turn abuts against a nut 35 threaded on the spindlb whereby the bearing housing is rotatable and movable axially a limited amount relative the spindle. The bearing housing mounts a thrust bearing assembly 36 in abutting engagement with a first metal washer 37. A lock nut 39 is threaded on and pinned through the spindle in abutting engagement with a second metal washer 37, there being provided a pair of resilient shut off valve washers 38 on the spindle between the first and second washer 37 and a third metal washer between the shut off valve washers 38. A second lock nut 39 is threaded on the spindle in abutting engagement with the inner end of the latch body and to be located axially outwardly of the first mentioned lock nut.

The inner end portion of the latch body has a plurality of circumferentially spaced, axially elongated grooves to provide teeth 26α. The axially inner portions of the teeth extend radially outwardly of the central axis of the core barrel inner tube assembly a shorter distance than the teeth axially outer portions to provide shoulders 26b against which the outer axial surface of a landing ring 42 abuts, the landing ring being press fitted on the latch body to move therewith. As may be noted from FIGURE 1, the inner diameter of the landing ring 42 is substantially less than the inner diameter of the landing ring 23. Further, the outer diameter of landing ring 42 is substantially greater than the inner diameter of landing ring 23 but substantially less than the outer diameter of landing ring 23. Through the provision of landing rings 23, 42 either one or both can be replaced in the event they become damaged.

Additionally, the inner axial ends of the latch body teeth extend, a substantial distance axially inwardly of the landing ring 42. Accordingly, the landing ring 42 in a core barrel inner tube core taking position seats on landing ring . 23 for supporting the core receiving tube out of abutting engagement with the core barrel outer tube assembly and at the same time the grooves in the latch body provide fluid bypass channels to permit fluid to flow from the annular space between the core barrel inner tube assembly and the core barrel outer tube assembly axially outwardly of rings 23, 42 to the annular clearance space axially inwardly of said rings.

A through pin 51 mounts the insert block 25 in the axially elongated latch body slot 26c while a pair of through pins 48 that are mounted in parallel relationship mount the latches 15 and 16 for pivotal movement. To be noted is that the latches 15, 16 are mounted in a common plane in a common slot, the width of the slot 26c in a direction parallel to the pivot axis of pins 48 being only very slightly greater than the corresponding width of a latch. Further, the inward end portions of the latches are rounded to form a close fit with the arcuately curved portions of the insert 25, i.e. the insert having a central portion projecting axially outwardly between the adjacent rounded portions of the latches whereby the latches directly transmit a force from the drill stem to the insert.

The latch release tube 27 is mounted on the outer reduced diameter portion of the latch body that extends outwardly of the latch body teeth for slidable movement between a position abutting against the latch body shoulder 55 and a position axially spaced therefrom. Tube 27 has diametrically opposed slots 56 through which the outer transverse corner portions of the latches may extend to latchingly engage the latch seat 21α. A torsion spring 57 within the latch body slot resiliently urges the latches to pivot about their respective through pin 48 to positions to latchingly engage the latch seat 21α.

An axially elongated slot 58 is formed in the latch body on either side of slot 26c to extend transversely thereto. A through pin 60 is extended through the slots

3,461,981

26c, 58 and and has its opposite ends mountingly retained within opposed apertures in the latch release tube to move therewith. The slots 58 extend axially inwardly sufficiently such that when the pin 60 abuts against the inner edges thereof, the pin is located transversely intermediate the latches and the latch release tube abuts against the latch body shoulder 55; and the pin in an axially outer position, the latch release tube is moved sufficiently relative the latch body to retract the latches. Thus, pin 60 limits the movement of the latch release tube outwardly relative the latch body.

A plug 64 has an inner portion extended into the latch release tube, said inner portion being secured to the latch release tube by a pin 66 to prevent movement of the plug relative the release tube. The plug has a spear point 64α extending outwardly beyond the release tube.

The inner end portion of the cap 29 has an axially extending bore 67, bore 67 having an internally threaded inner end portion 67α that threadingly engages the external threads of the inner tube 28. Bore portion 67α opens to a reduced diameter intermediate, threaded bore portion 675, which in turn opens to the axially outer bore portion 67c. A plurality of transverse bores 68 at their one ends open to bore portion 67c and at their other ends open to the cap exterior surface. Mounted in bore 67 is a check valve that comprises a valve seat member 69 that threadingly extends into bore portion 67b. The valve seat member has an internal bore 70 that has an axially intermediate bore portion 70α that is of progressively smaller diameters in an axially inward direction. An O-ring 71 is mounted in a groove in a portion of the valve seat member that defines bore portion 70α, there being provided a steel ball 72 seatable against the O-ring to prevent fluid flowing radially inwardly through channel 68 and thence through bore portion 67c to bore portion 67α; but at the same time permitting the ball 72 moving axially outwardly of the O-ring to permit fluid flow through bore 70 from bore portion 67α in a direction toward and to bore portion 67c. Through the provision of this structure a substantially greater volume of fluid may flow from the inner tube to bores 68 than through a small vent hole in the inner tube, but at the same time prevents fluid flow in the opposite direction.

Slidably mounted in the core barrel inner tube is a plug 74, said plug having an external annular groove that mounts an O-ring 75 for forming a fluid seal between the plug and the inner peripheral wall of the inner tube. The plug has a cylindrical recess 76 that opens toward the valve seat member, the inner diameter of said recess being larger than the maximum outer diameter of the valve seat member. A threaded bore 77 is provided in the plug to open to recess 76 and through the surface of the plug axially opposite said recess.

The inner end portion of the plug is of a slightly reduced diameter to provide a shoulder 78, the outer end of the third tube (tube liner) 80, 81 being seated against said shoulder. The third tube is made up of two half sections, each of which in transverse cross section extends through an arc of 180°. The third tube is of very thin material, for example of steel, and is of such a size to fit snugly inside the inner tube 28 when in place. In order to keep the third tube from moving axially out of contact with the plunger 74, there is provided a beveled stop ring 83. The stop ring is mounted in an annular groove or recess 84 formed in the inner peripheral wall of the core lifter case 85, recess 84 having an annular edge substantially coextensive with the inner annular edge of the inner tube when the core lifter case is properly threaded on the inner tube. The stop ring is a hard resilient steel snap ring that is axially split at 83α and has a beveled edge 835 that in an axially outwardly direction, extends radially inwardly toward the central axis of the core barrel inner tube assembly. Further, the beveled edge is angled at about an equal but opposite angle relative the inner beveled edge of the third tube, the beveled edges being radially opposite one another even when the stop ring is moved in the recess 84 a maximum distance axially away from the inner tube. Further, the inner diameter of the stop ring is less than the inner diameter of the third tube when it is in place in the inner tube 28.

Mounted within the core lifter case for limited axial movement between the position illustrated in FIGURE 2 and a position abutting against the stop ring 83 is a core lifter 87, the core lifter case and core lifter 87 having abutting beveled surfaces to limit the maximum movement of the core lifter away from the stop ring to the position shown in FIGURE 2. The maximum inside diameter of the core lifter 87 is the same or slightly less than the inside diameter of the stop ring; while the diameter of the core bit aperture 115 is substantially the same as the maximum inside diameter of the core lifter.

An axially elongated groove 11c is formed in the inner peripheral wall of the bit 11 to have one end thereof opened between the stabilizing ring casing 14α and groove 11α, grooves He, 11α being radially opposite the core lifter case when the core barrel inner tube assembly is in a latched seated, core receiving position. A plurality of circumferentially spaced, axially elongated holes 88 at their one ends open to groove 11c and at their opposite ends through the bit face lid at locations radially outwardly of the bit aperture 115. Axially between groove 11c and aperture 115, the core bit and core lifter case (when the core barrel inner tube assembly is in a core receiving position) form a loose slip fit one inside the other to provide a restriction to the flow of cooling and flushing fluid so that the greater portion of said fluid must pass through the holes 88 and out across the face of the bit. A small part of the fluid passes between the core lifter case and bit and outwardly through the aperture 115. The purpose of the above is to direct most of the fluid away from the inner peripheral wall of the bit defining aperture 115 to prevent the fluid washing away the soft areas of the core.

In order to facilitate the removal of the third tube from the inner tube, there is provided a small plug 96 for being threaded in bore 77 of plug 74 to block passage of fluid through said bore, and an auxiliary cap 91 to be threaded on the outer axial end of the core receiving tube 28. A line 92 connects the cap 91 to a pump 94 for applying fluid under pressure to the interior of cap 91, there being provided a valve 93 in line 92 for discontinuing the application of fluid under pressure through the line.

The apparatus of this invention having been described, the use thereof will now be set forth. For purposes of facilitating the description and operation of the inner tube assembly 15, it will· be assumed that the drill stem is extended into a hole in the earth formation in a generally vertical direction and that the core barrel inner tube assembly is being lowered in the drill stem. At this time the latches are retained in a retracted position by the inner peripheral wall of the drill stem. If the inner tube assembly is being lowered at a sufficiently high rate of speed, if fluid were trapped in the core barrel inner tube, it would act to compress the shut off valve washers 38 to an extent to block the passage of fluid past said washer. However, the fluid in the inner tube passes through bore 77 and moves the ball 72 relative the valve seat member to permit fluid to flow through bore 70 and axially outwardly through bores 68. That is, in some cases with prior art core barrel inner tube assemblies where only a small vent hole is provided to the core barrel inner tube, the small vent hole does not allow enough fluid to bypass with the result that such an upward pressure was developed (especially in larger diameter models) that the rubber shut off valves 38 were compressed to such a degree as to be permanently deformed.

As the inner end of the core lifter case moves adjacent to the portion of the bit defining aperture 115, the latches 15 and 16 are located radially adjacent the latch seat, and are resiliently urged to a latch seating condi3,461,981 tion by the torsion spring. Further, at this time the core barrel inner tube assembly landing ring 42 abuts against the core barrel outer tube landing ring 23 to support the core barrel inner tube assembly in the position illustrated in FIGURES 1 and 2. At this time, there is provided a fluid bypass channel that extends from axially adjacent the plug 64, axially along the latch release tube and thence radially inwardly through the latch body grooves to bypass the landing rings 23, 42 and then downwardly in the drill stem to adjacent the stabilizer ring to bypass said stabilizer ring and then through the groove 11c and primary outwardly through holes 88 and partially outwardly through the drill bit aperture lib as previously described. Now the core drilling operation is started whereby the cutting of core is begun. Because of the shape of the core bit, an even deepening hole is cut with a rod shaped core being produced. As the drilling continues, the core barrel outer tube and core bit move relative the core whereby the core extends through the core bit aperture 11b and thence in the core lifter case to abut against adjacent surfaces of the core lifter. As the axial length of the core increases, the core lifter case moves relative the core lifter until the core lifter abuts against the stop ring. Thereafter the core lifter case, the core lifter and the stop ring and the core barrel inner tube move together as a unit. Further drilling results in core being received in the third tube 80, 81. The drilling of core results in core moving into the core barrel inner tube and third tube and pushing fluid outwardly through bore 77, bore 70 and bores 68. However, ball. 72 prevents the flow of fluid in the opposite direction which, if not blocked, would wash away soft portions of the core.

After core of the desired length has been cut, for example when a high pressure signal is applied at the surface through the provision of the resilient shut off washers 38, the drilling is stopped and the drill stem pulled outwardly a short distance. Pulling of the drill stem outwardly results in the core lifter case moving axially relative the core and the core lifter whereby through the drag of the core lifter and the core, the core lifter is further axially spaced from the stop ring and is transversely compressed to grippingly hold the core and break the core. Now the core barrel inner tube assembly along with the core is retracted by a suitable overshot assembly (not shown).

After the inner tube assembly full of core has been retracted from the hole, the core lifter case 85 is unscrewed from the inner tube 28, and the inner tube is unscrewed from the cap 29. Now the pipe plug 90 is threaded into bore 77 and cap 91 threaded on the outer axial end of the core receiving tube. At this time plugs 90, 74 and the O-ring provide a piston inside the inner tube 28. Upon opening valve 93 to apply fluid under pressure from pump 94 to cap 91, the plug 74 is forced axially toward the inner axial end of the core receiving tube, and as a result of the plug abutting against tube sections 80, 81, the third tube is forced out of the inner tube 28. Once the third tube has been removed from the inner tube, the top half of the third tube can be lifted off, exposing the undisturbed core sample which is supported in place in the other half section of the third tube. Thus, during the time the core is being removed from the inner tube, the third tube retains the core in the condition in which it was drilled.

In addition to being useful for forcing the third tube out of the inner tube, the plunger 74 serves another useful purpose. That is when the third tube is to be inserted into the inner tube, plunger 74 retains the split tube sections in proper relative positions as the third tube is inserted into the inner tube.