US2079941A - Core catcher retainer and seat for a core barrel - Google Patents

Description

' Ma-y'11,19371 2,079,941

` FOR A CORE BARREL Fild Nov. 21, 19:55

G. J. LABARRE CORE dTHER-RETAINER AND SEAT Patented I May 11,. 1937 @TATES conn `chromen.RETAINER AND SEAT Fon A com: BARREL f i l 3 Claims.

The present inventionrelates to a core catcher retainer anc. seat for a core barrel of the type in which the vcoretaker is dropped intothe drill stein andthe core taken `witlioutremoving` the ,drill from the well. .y y y An object oi the invention is to provide anintegral structure to be fastened to a core barrel 4 and which at once. serves to hold thercore catcher in position and to provide asealwith `the drill tit.

Another Objectis @eliminate the use of de,

vices to lock the core taker in the drillbit.

The following additional objects areacconi? The core barrel may be any piece of pipe having the proper diameter and threaded. at each end; the core taker is sealed-against the iiushing liquid; the ywear is taken by an` elastic ring which prevents damaging of the other parts and which is readily renewable; the `core catcher is always free to revolve; and the device isto be used with conventional type equipment. y' d .A

With the foregoing andfother objects in View, the invention will be more fully described hereinafter, and will be more particularly pointed out in the claims appended hereto. l

In the drawing, wherein like symbols refer to like or corresponding parts throughout the several'views, y

Figure l is a sectional view of a drillcollar and bit and a core taker made according to the present invention.

Figure 2 isa transverse secticntaken on `the line 2--2of Figure l, and p Figure 3 is a detail sectionof the' retainer and seat. y

Referring now to Figure l, I designates a drill collar which is affixed `to the bottom of the drill stern and rotated with it. The drill collar I0 carries at its lower end the drill bit II `which holds the cutting blades i2.` `This drill bit is pro-` vided with channels i3 for lubricating and flushing the cutting surfaces of the cutter blades I2. In the type of drill bit to be used there is a central bore it for the purpose of admitting a` core taking tool and the bit is provided at the lower end of this bore with a cutter head I5 for taking the core as the bit is advanced.`

The usual core taking tool consists ina barrel i6 on the tcp of which is fitted a valve cage I1 for the purpose of draining the core barrel IB as it is dropped through the drill stem. `For this purpose the cage I'iis providedwith outlet ports I8 in its sides and with a conventional ball valve (01.255-72l y I eating with the core barrel andw'hich'lvalve is PATENT orifice urged to closed position by'the'spring 20. To

2i 'which is used in retrieving the coreitakerfrom th bill.`

The head of the drnibitcuts out the core as it advances into the ground and forces itlup thruthe bore I4. As a rule a lubricating` and flushing liquid'is circulated down thru the same bore before being forced out in front of the cutter blades I2 thru the channels I3. When taking a sample core it is, therefore, necessary l to seal the core barrel and thesample from this iluid in the bore. This seal has been formed in various ways before, such 4as byusing a set of rubber cups around the core'barrel.` There is also required in a core barrel alcore catcher which serves to retain the core` in the barrel as it is drawn'upV thru the drill stem. In the I present invention combines the duid seal re `quired to prevent contamination of the'sample core `and the core catcher retaining groove or seat into a single article which fulfills these purposes in a manner far superior to the separate' devices formerly employed and in addition ac oomplished a number of other objects.` The form illustrated consists in a cylindrical body portion 22 one end of which (thelower end as used) is reduced to provide a seat for a sealing ring 23 oi rubber or other flexible material. The ring I 23 is subjected to an upward thrust 1in` use andA the body 22 is therefore provided withthe downwardly'4 facing shoulder 24to provide` a backing ior the ring against this thrust. The body 22 is again reduced below `the ring to form the downwardly tapering shoulder 2 5 Awhich rests on thecore' cutter headl5 at the end of the drill bit. Internally the device is bored to receive the corecatcher and thecore barrel I6. `The upper part of the bore is made of greater `diameter than the outside of the core barrel I6 so that it passesthru the body freely.` At a lower point,`

in the neighborhood of the sealing `ring 23, the bore is reduced and threaded for a distance to receivethe'threaded end of the core barrel, forming the socket 26. Below the socket 26 the bore is smooth for a space and then is reduced the upper end of the assembly is fastened a spear to form a shoulder 21. There is thus formed a groove or annular retainer between the end of the core barrel I6 and the face of the shoulder 21 in which is placed the core catcher consisting of a ring 28 and spring ngers 29 securedthereto. The distance between the end of the core barrel in position and the face of the shoulder 21 is xed to suit the type of catcher to be used and must be such that the ring is free to revolve with respect to the retainer at all times.

For convenience in handling the retainer and seat is provided with a set of Spanner holes 30. The use of a spanner wrench protects the surface of the device from the roughening resulting from the use of a Wr-ench of the Stillson type.

The structure of the device is thus seen to be very simple and foolproof. ,In assembling the core taker it is only necessary to drop the catcher into position in the retainer and screw onto the barrel. It will be noted that the socket 26 is located'at the lower end of the bore; this causesv the force of the core barrel to be exerted directly against the sealingring 23 and the surface 25. Likewise the upper part of the bore is larger than the barrel permitting flexing of thebarrel in the socket as the retainer and seat adjusts itself in the bit.

This retainer and seat is designed to be used with a drill bit of the type in which the cutter headis built at the end of the boreprovided for core taking and in such a bit the device will rest on the cutter head and on the usual shoulder provided a short distance above the head. The lower end of the retainer is tapered to seat against the cutter head While the rubber ring 23 is provided to form a seal with the seat of the drill bit. The only requirement as to size of the drill bit is that the core taking bore be not a great deal larger than the smallest tool joint in the drill stem as the diameter of the core taker including the seats in vthe drill bit otherwise therewill be no seal formed.

The core taker to be used with the present device consists in the ordinary valve cage and overshot spear assembly but may have for a core barrel any'length of pipe of suitable diameter having threads at each end. The upper end is secured into the valve cage assembly and the lower end into the retainer and seat. It will thus appear that as any piece of pipe may be .usedv the length of the core to be taken may be varied at will.

Whereas formerly the core barrel required to be machined and was of expensive construction so that it was not practical to have various sizes of core barrels. Before the core barrel is fastened to the retainer a core catcher of the conventional ring type is droppedonto the seat below the threaded inner portion of the retainer and then when the core barrel is secured into position the catcher is held in an annular track which is designed to be of sufficient height so that the catcher will always be free to revolve.

The retainer will be made of a high grade forged. steel andheattreated for hardness. In addition to this the points which will receive the greatest amount of wear will be protected with a harder metal such as stellite. The ring 23 will be made of rubber and may if desired be reinforced with fabric.

When in position in the drill bit it will be noted that the top of the retainerl is below the inside port vholes for the water containers 3 in the bit and therefore there are no channels required in the retainer as are found in many of the retainers known in the art.

When it is desired to take a core the whole core taking assembly is dropped into the drill stern. As the core taker strikes the mud and water in the stem the ball valve I9 opens permitting ow through the barrel so that the taker may progress downward through the mud. When tool joints are encountered the rubber ring 23 absorbs the greater part of the shock thereby protecting both the taker mechanism and the ljoints. As the core taker enters the drill collar and bil: the retainer will center up due to the closeness of its fit with the bore and will settle into position on the seat and against the core cutter head. When this position is reached the ball valve I9 will close and remain closed until forced open by the pressure of the core which is being introduced at the lower end of the barrel. As the core enters the barrel the catcher fingers 29 will engage it and remain stationary with it while the retainer and bit continue to rotate. When sufficient length of core has been taken the taker is shed out of the drill collar and raised to the surface. In the course of raising, the core is held in the barrel by the spring ngers 29 of the core catcher.

Using this type of retainer on the core barrel eliminates the necessity of using the usual latch assembly to hold the barrel down, and rubber rings used to receive shock in the droppingL of the barrel eliminate the renewal of expensive seats frequently necessary in other barrels. The bit used in connection with this retainer has the core cutter built right into it thus relieving the drilling operation from the necessity of carefully checking the weight carried on the bit which must be done when separate core cutters are used. The core cutter is reinforced as its wearing points by dressing and building up with hard metal just as is done with the cutter blades themselves. The advantages of this type of bit are numerous, it will drill faster and in gauge longer than the bit without the cutter head built into it, due to the control of water or mud. There is no danger of a core barrel becoming stuck due to the burning of the core cutter head as is the case where the core cutter head is secured to the core barrel. The bit to be used in connection with this core barrel can be of either box type or pin type, preferably box type and either two or more blades may be used on the gumbo bit. When used on a rock bit as many cutters may be employed as is thought desirable. The bit used will be drilled through center a small fraction of an inch larger than the outside diameter of 'the core catcher retainer so as to permit the retainer to drop in and be retrieved through the main body of the bit.

It is to be noted that this type of core taker operates regardless of the pump pressure used and also the speed at which the core is taken. Another advantage is that as the cutter head is not fast to the core barrel there can be no breaking of the core taking tool at the end of the drill bit.

It is obvious that variouschanges and modications may be made in the details of construction and 'design of the above specifically described embodiment of this invention without departing from the spirit thereof, such changes and modifications being restricted only by the scope of the following claims.

What is claimed is:

1. An integral core barrel attachment, comprising a cylindrical body portion having an integral inwardly extending flange at its lower end for supporting a core catcher and provided above said ange with an integral socket portion `to receive the lower end of a core barrel and hold the same above the core catcher for conning thelatter between the core barrel and the flange, said cylindrical body also having an exterior gasket supporting portion in the zone of said internal iiange adapted to carry a sealing gasket to engage the seat in a drill bit, said cylindrical body further having a downwardly tapering portion below said gasket supporting por tion for engagement in the drill bit below the der. and a seating and shock absorbing ring on the body against said shoulder, said ring adapted to rest on said annular seat and being of the same diameter as the body so as to lie ush with the sides of said body to exert the pressure of the apparatus directly on the said annular seat to seal against flushing liquid in the bore of said bit.

3. In combination with a drill bit having a central sample taking bore, a sample cutter at the end of the' bore and an annular seat in the bore above the cutter; a core catcher retainer and seat for a core barrel comprising a hollow cylindrical body of a diameter substantially the same as that of the bore in the bit, said body having a downwardly directed external annular seating shoulder near its lower end, a seating and shock absorbing ring on the outside of said body against said shoulder for engagement on said annular seat in the bit, core catcher retaining means inside said body, and core barrel holding means inside said body.

GUSTAVE J. LABARRE.

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