US2494363A

US2494363A - Core barrel

Info

Publication number: US2494363A
Application number: US569473A
Authority: US
Inventors: Benjamin W Sewell
Original assignee: Standard Oil Development Co
Current assignee: Standard Oil Development Co
Priority date: 1939-12-21
Filing date: 1944-12-23
Publication date: 1950-01-10
Anticipated expiration: 1967-01-10

Description

Jan. l0, 1950 B. w. sl-:wELL 2,494,363

CORE BARREL l original Filed Deo. 21, 1959 ATTORNEY.

Patented Jan. 10, 1950 UNITED STATES PATENT OFFICE GORE BARREL `Benjamin W. Sewell, Tulsa, Okla., assigner to Standard Oil Development Company, a corporation of Delaware Original application December 21, 1939, Serial No.

i claims; (o1. .c55-72)' VThis is a division of Serial No. 310,284, led

December 21, 1939, now U. S. Patent 2,374,961 and a continuation-impart of applications Serial No. 242,211, filed November 25., 1938, now U. S. Patent 2,216,962, and Serial No. 269,168, led April 2l, 1939, now U. S. Patent 2,238,609, as to common subject matter therein.

The present invention relates to retractable core barrels formed to be dropped through the drill stem to a seat in a core bit and to take a sample of the formation. After a core has'been taken, it may` be sealed under the pressure of the formation and the core barrel withdrawn, leaving the drill stem and the drill in the lbore hole.

It is an object of the present invention-to provide a pressure core barrel which may be dropped down the drill stem and which will be latched in place when it is seated.

It is a further object of the present inventionto provide a device having both an outer pressure barrel and an inner barrel so provided with latches that the inner barrel maybe unlatched and dra-wn within the pressure barrel before the pressure barrel is unlatched from its seat.

Another object oi the present invention is to provide a pressure core barrel having upper and lower valves Vand arranged so that after it has been latched in place in a drill stein the lower valve may be closed before the device 4is unlatched from the drill stem and the upper one may be closed after it is unlatched from the drill stem. A further object of the present invention is to provide a core barrel which may be dropped down a drill stein and which is locked in place.

VWhen it strikes a seat at the lower end of the drill stem. The device is so arranged that, when a conventional type overshot attached to a wireline is dropped down the drill stem, it will fasten to a spear-shaped head on the upper end of the core barrel. Apull upwardly on the wireline will withdraw an inner barrel causing a vvalve in the lower end of the pressure barrel to close and a contimiedV pullwlll unlatch the device from the drill stem and then close a valve in the upper end of the pressure barrel, so effectively sealing a core in the barrel at the pressure of the formation.

Other objects and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawing in which i Fig. l is a cross sectional viewthrough a core drill with a preferred modification of the -device ofv the-present invention installed` therein;

Fig. 2 is a cross sectional view alone the line Fig. 3 is a fragmentary view of a lower portion of the device, taken at to the view shown in l and with Darts broken away to show details of construction.

Referring to the drawing in detail, numeral I designates a .conventional core bit head provided with conventional sn tail cutting edges Z --.2 and a central passage 3- The lower portion of the central passage 3 in drill head I has a -smaller diameter than the upper portion and forms a ledge Il Within the passage,

Core bit head is held in threaded engagement with the lower end of a collar 5, the upper end of theA collar being provided with threads (not shown) for engagement with a conventional tool joint. The lower end of the collar yis provided with a ledge 6 pieroedby central passage 3. vLocated on each side of central passage 3 are smaller passages I 'I which also extend through both ledge 6 and the bit head. Collar 5 is also provided with circumferential grooves I5 and yI6 located at a proper distance above ledge 6, as will hereafter'loe explained. n

Positioned within collar 5 is the pressure. core barrel. An outer cylinder 8 having suicient wall thickness to resist a large pressure differential has arranged within it a concentric cylinder 9. The lower end of cylinder 8 is upset to provide a threaded shoulder Ill to which is attached cylindrical sleeve I l, which has .an inwardly projecting shoulder I2 at its lower end. Sleeve AII is provided with inwardly projecting stub shafts I3--I3- Mountedon the stub shafts for rotation 'within the space defined by shoulders In and I2 and the interior of sleeve II is a steel ball I4. Steel ball I4 is provided with a transverse circular opening adapted to receive inner cylinder 9. Shoulders I9 and VI2 are suitably cut away to conform with the shape of steel ball I4 and, in

addition, shoulder Ill is recessed just above the cut-away portion to receive a packing ring I'I which is of vsuch configuration as to form a fluidti'ght seal with surface of the ball.

Stub shafts I 3-I3 carry springs I 8-I 8 and are provided with stops 29 which cooperate with projecting studsv I9 carried by steel ball I4 to limit the angular Vmotion of said ball to 90. The upper end of cylinder 8 is provided with screw threads and attached thereto by mating threads is a. cylindrical block 2|. Block-2| is in the form of a cylinder with outside portions of its upper end milled away to leave a circular shoulder 22 having ribs 23-23 joined thereto. Shoulder 22 screwed to the upper end of bolt 42. -upper face f cap 46 is arranged a disk of resilient is provided with a central passage 25 and has its under-portion bevelled for reasons which will later appear. A passage 26 of smaller diameter than the interior of cylinder 8 extends longitudinally from the lower end of block 2| to the cut-away portions thereof and has a knife edge 2`| formed onV the lower end thereof. Attached to ribs 23-23 by means of rivets 28-28 are dogs 29-29. The cylindrical block 2| is also provided with laterally olfset longitudinal passage 30 controlled by a needle valve 3| and when opened making connection with a lateral passage 32 provided with a plug 33 for the purpose hereafter specified. Access to needle valve 3| is provided by a slot 35 milled in block 2|.

Positioned within the pressure barrel is inner cylinder 9 provided at its lower end with a core catcher 34 and having a cylindrical valve head 36 attached to its other end by means of suitable screw threads. The valve head is provided around its circumference with slots 3l below which is arranged a seat 38 for a ball valve 39. The upper end of the valve head is provided with a recess in which thrust bearings 4| are arranged. A bolt 42 has its head 43 resting on thrust bearings 4|, the bolt being held in place by a screw cap 44 carried by the upper end of the valve head. A stud 45 is screwed into cap 46 which, in turn, is Upon the material 4l which is of such dimensions as to form a seat for the knife edge 2l attached to the lower face of cylindrical block 2|.

The stud 45 is screwed into a cylindrical block 48. rhe central portion of block 48 is provided with a slot 49 and attached within slot 48 by rivets 50-58 are dogs 5|-5|. Block 48 is also provided with laterally projecting pin 52. Fitting slidingly over block 48 is a sleeve 53 provided with a spear head 54 and lhaving its center portion providedwith slots 55-55 and 5656. Slots 55 are so arranged that the upper ends of dogs may extend outwardly through them when sleeve 53v is resting in its lowerrnost position in which the upper ends of slots 56 rest on pin 52.

An outer sleeve 51 fits slidingly over cylindrical block 2|. The upper end of sleeve 5l is provided with pins 58-58 which project into the slots .E5-55 of sleeve 53. Sleeve 51 is additionally provided with slots ssi-59 placed so that the upper F ends of dogs 25E-29 may extend outwardly through them when sleeve 5l is resting upon cylindrical block` 2| in its lowerrnost position.

The above described device may briey be said to comprise a heavy pressure barrel provided with valves at its upper and lower ends and an inner barrel slidingly arranged within the pressure barrel. When the device is ready for taking a core, locking means lock the inner barrel against longitudinal movement with respect to the pressure barrel, its lower end protruding from the lower end of the pressure barrel and other locking means, in turn, lock the pressure barrel in the lower end of the drill stem provided with a core bit. The lower end of said inner barrel projects into the head of the core bit in order to receive a core. When a core has been received by the inner barrel, a pull on the upper end of the device unlocks said inner barrel and retracts it within the pressure barrel to allow the valve in .the lower end ofthe pressure barrel to close. A continued pull on the upper end of the device next-unlocks the pressure barrel from the drill Vstem and then closes the valve in the upper end of the pressure barrel to hermetically seal the core within the pressure barrel.

The device is prepared for taking a core by having the longitudinal axis of the opening in steel ball |4 in line with the longitudinal axis of outer cylinder 8, the lower end of cylinder 9 being extended through the opening in steel ball I4 and then projected a predetermined distance beyond it. It will be apparent that cylinder 9 is the sole means for opposing the rotative force applied to the ball by springs |8| 8 and hence for retaining the opening in the steel ball in line with the axis of cylinder 8. In the upper end of the device, upper ends of dogs 29-29 and 5 |-5I are momentarily retained inwardly in order to allow sleeves 53 and 5'| to assume their lowermost positions, and are afterwards allowed to fall outwardly. When this occurs, relative longitudinal movement between cylinders 8 and 9 will be prevented because cylinder 8 is attached to block 2| While cylinder 9 is attached to block 48 through stud 45, and since block 48 rests on a face of block 2| it cannot move downwardly and upward movement is prevented by dogs 5|-5l resting against that part of block 2| which .forms shoulder 22.

With the inner and outer barrels locked together as described in the preceding paragraph, the device is ready to be lowered into a drill stem in order to take a core. A drill stem having at its lower end a collar and core bit head as shown in Fig. 1 may be in position in a bore hole with the cutting edges of the bit at the point in the hole at which it is desired to obtain a core. The core barrel may then be placed within the drill stem and allowed to fall under the force of gravity. If there is no obstruction within the drill stem, shoulder l2 will strike the ledge 6 of the collar and the device will then be locked in this position by dogs 29-29 which fall outwardly and engage notch i5, as shown in Fig. l. If there is a" small obstruction between ledge and shoulder |2, shoulder l2 will rest on this obstruction and the device will be locked in position by engaging notch I6. In either event the lower end of cylinder 9 will project within passage 3 for the purpose of receiving a core. After the device has been locked in place, the drill stem may be rotated and drilling duid forced down the drill stem and out through passages 1-7 into the bore hole in the conventional manner. As the drill stem rotates, cutting edges 2-2 will cut a core which enters central passage 2 and hence cylinder 9.

It will be evident that the rotary movement ci inner cylinder 9 will be independent of the rotary movement of the drill stem and the outer cylinder 8 because cylinder 9 is connected to these other members through the thrust bearings 4|. As the core enters cylinder 9, drilling fluid will be displaced upwardly through ball valve 39 and oui through slots 3l.

When a core of the desired length has been cui by the bit, the rotation of the drill stem may be stopped and an overshot attached to a wire line dropped down through the drill stem and allowed to engage with spear head 54. Since such overshots are conventional to the art, this device ir itself forms no part of the present invention and hence, is not illustrated in the drawing. An upward pull on the wire line attached to the overshot lifts sleeve 53 until the lower portions o:

Aslots 55 strike dogs 5|, pulling them inwardly thereby unlocking cylinder 8 with respect to cylinder 9. A continued pull upwardly on sleeve 5l causes pins 52 to rest on the lower ends of slot 56, transmitting the pull to stud 45 which retracts cylinder 9 within steel ball I4 and allows springs |8-l8 to rotate the steel ball to 90 to close off the lower end of cylinder 8. Continuing the pull on sleeve 53 causes the bottoms of slots 55 to strike pins 58 and pull sleeve 51 upwardly to disengage dogs 29 from notch l5. All the pull is now transmitted directly through block 48 to stud 45 which causes disk 41 to seat against knife edge 21, sealing off the upper end of cylinder 8 and allowing the force to be transmitted to cylinder 8 in order to withdraw the entire device from the bore hole.

When the device is withdrawn to the surface of the earth with a core under formation pressure in barrel 8, the gaseous components of the sample may be collected by removing plug 33 from block 2l and attaching a conduit from passage 33 to a suitable device for containing these components. Needle valve 2l may next be opened to allow the gaseous constituents to be withdrawn from the core barrel to the sample container, thereby relieving the pressure in the core barrel. The core barrel may then be dismounted to obtain the core and the core barrel then reassembled and arranged to take another core in the manner previously described.

While I have disclosed ya specic modification of the present invention it is obvious that various changes in the shape, size and arrangement of the parts may be made Without departing from the scope of the invention. For example, the number and shape of the locking dogs used in the device may be altered, other means may be used for withdrawing the gaseous constituents from the sample chamber and other types of core bits may be used. I therefore do not intend to be limited to the above described modicaticn.

I claim:

1. A pressure retaining coring assembly to recover a core on the surface of the ground at thesame pressure the core left the formation, comprising a string of drill tubing, a core barrel adapted to be lowered into and raised completely out of the string of drill tubing during normal drilling operations, a bit having a passage in the center thereof attached to the end of the drill tubing to cut a core, the core when cut passing upwardly through the passage in the bit and into the lower end of the core barrel, a valve means arranged adjacent the lower end of the core barrel adapted when open to pass said core barrel and when closed to seal the lower end of said core barrel, said core barrel passing through said valve during the coring operation, and means carried by said core barrel for breaking off the core below said valve at the end of said coring operation.

2. A pressure retaining coring assembly to recover a core on the surface of the ground at the same pressure the core left the formation cornprising a string of drill tubing, a core barrel adapted to be lowered into and raised completely out of the string of drill tubing during normal drilling operations, a bit having a passage in the center thereof attached to the end of the drill tubing to cut a core, the core when cut passing upwardly through the passage in the bit and into the lower end of the core barrel, a rotatable valve arranged adjacent the lower end of the core barrel adapted when open to pass said core barrel and when closed to seal the lower end of said core barrel, said core barrel passing through said valve during the coring operation and means carried by said core barrel for breaking off the core below said valve at the end of said coring opera- `ing to its lower end, a seat on the lower end of the drill tubing to support the casing member when the core barrel assembly is in core-taking position, a bit having a passage in the center thereof attached to the end of the drill tubing to cut the core, a rst valve means associated with the upper end of the casing member and adapted to seal the upper end thereof in a duid-tight manner, a second valve means mounted on the lower end of the casing member and arranged for sealing the lower end thereof in a fluid-tight manner, a core barrel slidably mounted in the casing member and arranged to have its lower end extend below the second valve member into the passage of the bit when in core-taking position and to be within the casing member above the second valve member when in a retracted position, and core breakers carried by the core barrel at a point below the second valve member when the core barrel is in core-taking position.

4. A pressure retaining coring assembly to recover a core on the surface of the ground at the same pressure the core left the formation, comprising a string of drill tubing, a core barrel assembly adapted to be lowered into and raised completely out of the string of drill tubing during normal drilling operations and including a casing member having a central passage extending to its lower end, a core barrel slidably mounted in the casing member and arranged to assume a forward position and a retracted position, a seat on the lower end of the drill tubing to support the casing member when the core barrel asn sembly is in core-taking position, a bit having a passage in the center thereof attached to the end of the drill tubing to cut the core, a valve means associated with the upper end of the casing member and adapted to seal the upper end thereof in a huid-tight manner, a rotatable valve mounted on the lower end of the casing member and adapted to pass said core barrel when the latter is in its forward position and to seal the lower end of the casing in a uuid-tight manner when the core barrel is in its retracted position, and core breakers carried by the core barrel at a point below the rotatable valve when the core barrel is in its forward position.

BENJAMIN W. SEWEIL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,108,949 Snyder Feb. 22, 1938 2,164,598 Thrift July 4, 1939 2,216,962 Sewell Oct. 8, 1940 2,238,609 Sewell Apr. 15, 1941 2,374,961 Sewell May 1, 1945