US2287909A

US2287909A - Expansion chamber for pressure core barrels

Info

Publication number: US2287909A
Application number: US318266A
Authority: US
Inventors: Benjamin W Sewell
Original assignee: Standard Oil Development Co
Current assignee: Standard Oil Development Co
Priority date: 1940-02-10
Filing date: 1940-02-10
Publication date: 1942-06-30
Anticipated expiration: 1959-06-30
Also published as: GB547065A

Description

`June 30, 1942. B. w. sEWLL EXPANSION CHAMBER' FOR PRESSURE coRE BARRELS FiledFeb. `1o, 1940 2 sheets-sheet 1 ATTORNEY.

June 30, 17942. B, SEWELL I 2,287,909

EXPANSION CHAMBER FOR PRESSURE CORE BARRELS BY AJ. Cmk

ATro-RNEY.

Patented June30, 1942 v ORE BABBELS Benjamin W. Sewell, Tulsa, Okla.,` assignor to Standard Oil Development Company -acor- Y poration of Delaware Application February l0, 1940. Serial No. 318,266

(ci. ess-12) .claima The present invention relates to expansion members for pressure core barrels. It is an object of the present invention to provide a pressure core'barrel with means for reducing the differential pressure in the barrel when it is withdrawn to the surface of the earth.

It is a further object of the present invention to provide a pressure core barrel with expansible means which will allow the pressure chamber to increase in volume as the core barrel is withdrawn to the surface of the earth and thereby reduce the pressure dlerential within the core barrel.

Another object of the present invention is to provide a core barrel with means which will rev tain the fiuid'in the barrel and yet allow the pressure in the barrel to -be substantially reduced below the pressure of the formation from which the core is obtained.

Other objects and advantages of -the present I invention may be seen from reading the following description and by reference to the accompanying drawings in which:

Fig. 1 is a cross sectional view of a portion of a. pressure core barrel showing one modication of the present invention applied thereto;

Fig.2 is a cross sectional view of a portion of a core barrel similar to that shown in Fig. 1 having yapplied thereto another modication of the present invention;

Fig. 3 is a cross sectional view of a portion of a core barrel showing applied thereto another modicationofthe present invention, while Fig. 4 shows the Asame portion of a core barrel illustrated in Fig. 3 having-.applied thereto still another modification of the present invention.

to Flai, numeral 5 isa cylinder which 'forms a portion of a drill stem. Concentrlcally inside of cylinderv 5 is cylinder 35 whichis provided at its upper end with a cylindrical block 36 provided with a central passage 31. Central passage 31 is enlarged at its lower end to provide annular space 38. At the lower end of annular space 38 is downwardly extending knife edge 53. A radial passage 39' connects space 38 witlr'the exterior of the block. The block is also provided with a laterally offset longitudinal passage 40, controlled by a needle valve 4l and", when open, making connection with a lateral passage l2 provided with a plug d3 Afor the purpose hereinafter specified. Block 36 `isprovided radially extending longitudinal fins ad which space it from cylinder 5.

ceive a core. This core receivlngcylinder is connected to collar 5l which, in turn, is connected to the lower end of rod 25. y As may be seen in the drawings, rod extends upwardly through centrai passage 31 and is connected at its upper end While the present invention maybe appliedf generally to pressure core barrels, it isv shown in the present application as applied to the pressure core barrel described in my Patent 2,238,-

609 o i April 15, 1941 to facilitate the description thereof, parts are designated by the same numerals asare applied to like parts in the abovel mentioned copending application. The complete pressure core barrel described in said patent has not been shown in the present application because the means herein described are applicable to pressure core barrels in general and are not dependent on the mechanism used in any particular core barrel. The operation of the present invention and its relationship to pressure core barrels will be clearly understood from the folonvgvsing description of the accompanying drawaferrmg to die drawings and am 55.

with a coupling 2li which, in turn, is connected to a rod 20. Collar 5l is provided with a laterally extending upper face upon which is. arranged a strip of resilient material 52 of such dimensions as to form seat for the knife edge 53 for reasons ,which will be hereinafter explained.

' Extending upwardly from block 36 is a sleeve de concentric with,v coupling 2B, said sleeve normally having a .smaller inner diameter than the outside diameter of coupling 2l. but being reamed out to form a sliding t for said coupling for a length defined by shoulders and 48, whereby said vcoupling is permitted limited longitudinal movement within said sleeve' for the purpose hereinafter specified. p

At its upper end sleeve Il is provided with radially extending longitudinally arranged iins 41 which have inclined upper edges I8 adapted to form ai' seat for the bevelled edge 49. of the inside edge o the lower end of a cylindrical section 1. Sectio 1 is also provided adjacent its lower end with a external shoulder 50. There is a linkage between ection -1 and the upper end of rod 20 which is not shown in the drawings.

In this figure an expandable means is provided by a rubber sleeve Ili which embraces metal cylinder 35. Clamps |02 form a fluid-tight joint between-sleeve IUI and cylinder 3.5 at the endsexpandable a core in the manner conventional to the art and as the solid core enters the cylinder 35 it displaces drilling fluid through passage Il. After a suitable core has been cut, an upward pull is communicated from sleeve 1 through the locking means, not shown, to rod 2l which. in turn.`

communicates the pull through collar 2l, rod 25 and collar I to the inner core barrel (not shown). This upward pull withdraws the inner core barrel within cylinder 3l and allows a valve (not shown) at.the lower end'of cylinder 35 to A continued pull draws collar 5| provided close. with seat 52 against knife edge 53 eilectivelyclosing the upper portion of cylinder 35. With Acylinder 35 sealed on'. at the upper and' lower end the core barrel containing the core may Abe withdrawn to the surface of the earth.

` It will be appreciated that, when the core is obtained. it is sealed in a duid-tight manner under the pressure of the formation from which it is obtained and that ordinarily, as the core barrel is withdrawn to the surface of the earth.

the -pressure differential becomes successively greater because the pressure on the exterior of the cylinder holding the core`becomes' less and: less, while the pressure within it remains constant. However, in the present'case cylinder 35 is provided with expansible sleeve lli which allows the gases within the pressure core barrel to expand. At the formation pressure the gases in the core occupy only a small part ol?` the total volume occupied by the core, so the volume required for gas expansion in order to greatly reduce the pressure within the barrel need not be large. It will be understood that the volume required. for expansion may be several times larger than the volume required to contain the core itself, but that this volume is not large compared with the great pressure reduction obtained. For example. it is preferred to keep the differential pressure within the core barrel at from fifty to one hundred pounds 'per square inch when the device is withdrawn to the surface of the earth, and 'at times the formation pressure under which the core is sealed within the barrel may be as great as four thousand pounds per square inch. It will be understood that the drawing is not shown Ato scale and that communicates with the interior of the core barrel in this figure the cylindrical head 36 is proarubber balloon.

the lower portion of arm 41 is of such dimensions as to provide room for the expansible member |05. It will be understood that in withdrawing the device from' the bore hole shoulder 41 moves upwardly with respect'to the upper face of block 35, seals the upper end of cylinder I5 and, in so doing, increases the space in which the Sylphon bellows l I5 may expand in order to reduce the pressure within cylinder 25.

Fig. 3 is a view of the portion oi' the core barrels illustrated in the preceding fisuras provided with an expansible member |05 in the form o! This device is operated in the same general manneras the Sylphon bellows shownin Fig. 2, the only dinerence being that a balloon is used as the expansible member in stead of the Sylphon bellows.

In Fig. 4, aa modincation of the 4invention is shown in which the expansion member is telescoping member |01. -The device shown in this figure operates in the same manner as that shown in Figs. 2 and 3.

While I have shown the modiiication o! the present invention as applied to the core barrel described in my copending application Serial No. 269.168, it will be apparent that these medidostions may be applied to the pressure core barrels shown in copending Patents Nos. 2,213,595 of Sept. 13, 1940, and 2,216,962 of Oct. 8, 1940, and copending application No. 310,284 filed Dec. 21, 1939. The modifications of the present invention may be applied not only to any of the above mentioned core barrels, but also to other pressure core barrels to which an expansible member may be attached to allow the pressure within the. core barrel to be reduced as the core barrel is withdrawn from the bore hole to the surface.

of the earth.

Having fully described and illustrated the present invention, what I desire to claimvis:

1. In a pressure core barrel provided with a pressure chamber adaptedto be closed in a fluidtight manner, a duid-tight expansible member fluidly connected to the pressure chamber.

2. A pressure core barrel comprising .a cylin- 4. An apparatus in accordance with claim 3 in which the expansible-member comprises a rubber sleeve circumferentially embracing the cylindrical member and provided with clamps firmly attaching its ends to said cylindrical member.

5. An apparatus in accordance with claim 3 in which a .chamber having expansible walls-is attached to the upper end of the core barrel and by a passage through its upper end.

6. Anv apparatus in accordance with claim 3 in which the expansible member is a telescoping device arranged in the upper end of said core barrel.

BENJAMIN W. SEWELL.