US 1606606 A
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Description (OCR text may contain errors)
Nov. 9 1926. 1,606,606
w. T. THOMAS APPARATUS FOR CEMENTING WELLS Filed June a, i926 31a/vanto@ T/zvmas 'ibatenteld Novo 9 i226.,
intere rarer-rr entre WELLM T. THOMXS, OFIWXCHITA FALLS, TEMS, ASSIGNOR Oli? ONE-HALF T AMERI- UAN lEtN @L MACHINE WORKS, m0., @3F TONKAWA, KLAHOM., A CRPQMTIUN or ontsporen.
application med June t,
This invention relates to apparatus lfor cementing wells and more particularly to an improvement of that type of cementing apparatus illustrated in my prior patent, No.
e 1,576,074, granted March 9, 1926, for apparatus for sealing oil wells.
An important object of the present invention is to provide a construction such that improper location of the cement charge which is being placed in the well is 'absolutely avoided. ln cementing wells by the process employed in the patent above referred to and by similar processes, the cement charge is placed within' the casing. Upon this l5 charge is placed a plug, the function of which is to maintain the charge in position after it has been forced into such position by hydraulic pressure applied through a pump connected with the casin at the u per end thereof. These plugs, i they fit t e casing, often seal above the cement an air pocket, the length of which causes a corresponding displacement of the cement charge,
so that it is improperly spaced. Furthermore, the upper surface of the cement mingles with the hydraulic charge, so that the cement is rendered extremely soup and instable, so that it requires a relatively long time for 'the cement tol set and ad]acentthey lower end of the casing, into which the cement tends to return, there is often a pocket vin which the quality of the cement is so poor that a proper setting thereof is not effected by the time the drilling is begun. In ac- 'cordance with the present invention, means `are provided to prevent the formation of an air pocket and to permit -the cement to return to a predetermined level and by its own pressure drive therefrom any excess fluid which would tend to cause improper setting thereof.
Furthermore, in setting cement in oil wells vby the process set forth in my`^ prior patent, the arrival of the plug at .the pro er point in the casing is determined by the act that since no further duid can flow into the casing, the hydraulic pressure employed for driving` theplug and cement downwardly builds up'relat-ively rapidly. The lug once in position is locked in this osition, so that it cannot return and provides aperpetual seal, so that when the pump pressure is re- APPARATUS EUR CEMENTEE@ WELLS.
1.926. Serial No. 114,492.
moved, there is no tendency to back-How of the fluid employed in providing the pressure against the cement. A further and important object of this invention is to provide a device of this character which, while giving the indication of the arrival of the plug at the proper position in the same manner as in' my prior patent, permits the lug to shlft after it is engaged .with its seat through a vpredetermined distance, which opens a number of minute openings through which water may pass but in which the cement has a tendency'to clog.
These and other objects I attain by the-"- Figure 3 is an enlarged detail sectionalA view through the disk showing the Amanner 3f lrr'egulating the size of the; openings of the lReferring now more particularly to the drawings, the numeral 10 generally designates a casing of a well bore ll-which is to be cemented and 12 indicates a shoe of the casing which is disposed at the lower end thereof. In according with my invention,
a disk 13 is placed Within the casing adjacent the shoe 12' and is preferably held in position by a coupling 14 connecting the shoe with the lower end of the casing. This disk has a central opening 15 in the lower end of a depending neck 16, the upper sur'- face of the connection of the neck withth disk roviding a valve seat 17'. I
llhls disk is formed with a plurality of minute openings`18 which may have any. suitable arrangement and a number of which areformed. in,the neck 16 of-the disk. Theseopenings are preferably about one sixty-fourth of anv inch in diameter.
' no part of my invention.
The plug employed consists of a cylindrical body 20 of less diameter than the interior diameter of the casing in which it is to be employed and is formed at its lower end with a head 21 having a neck 22 of a size to extend through the neck 16 of the disk 13 and the opening 15 thereof. The
lower endA of the neck 22 has an openlng 23 in opposition to which is arranged an upwardly cupped washer element 24 formed of flexible material. This washer element is supported by a rod 25 threaded in the upper head 26 of the plug and extending "through the neck 22 of the lower head 21 thereof. The lower end of the rod has a head 27 and between this head and the washer a spring 28 is disposed which normally urges the washer upwardly for engagement with and sealing of the opening 23 of the neck.l Both the upper and lower heads of the plug may be provided with 'a series of small openings 29, if so desired.
The exterior of the plug adjacent its upper end has preferably secured thereto an annular bristle clump 30, the bristles o f which are relatively sti and engage against the walls of the casing. These bristles serve to brush from the walls of the casing any cement which has a tendency to adhere thereto, so that' this cement will not dry u on the walls of the casing and afterwards uring the drilling operation flake 0E.
The method of employing the apparatus is as follows: The disk 13 having been positioned and cemer admitted to the well, the plug is dropped in o top ofthe cement and hydraulic pressure applied to the well to force the cement to its position between the wall ot the bore 11 and the casing. When the plug comes into contact with the disk, the washer 24 will pass below the disk and the plu will come into sealing engagement with t e seat 17. 'Ihe sudden rise in pressure will advise the operator of the pump that the plug is in engagement with the disk and 'pressure is shut 0E and the well opened. he cement will then tend to return to the casing and the Huid on top of the cement will be forced through the openings 18 and thus permitted to escape from the cement. The cement coming into contact with these openings will seal the same, preventing loss of any appreciable quantity of the cement. At the same time, liquid or air may move through the interstices `of the cement particles to the openings and thus escape.
It isv pointed out that at this time, the plug'20 may move upwardly so that this plug does not seal the openings 18, washer 24 coming into engagement with the lower end of the yoke 25 and providing a seal for the large opening 15 of the disk 13 while at the same time limiting upward movement of the plug. While the plug 20 will not seal all of theopenings 18, when seated thereagainst, it is advisable that this plug4 be permitted to move upwardly, as otherwise a complete separation of the water and cement is difcult to obtain. These openings 18 will, of course, permit the passage not only of water but any other trapped Huid, suchv as air.
Since the construction hereinbfefore set forth is obviously capable of a certain range of change and modification without matcf rially departing from the spirit of lthe invention, I do not limit myself to such spe- A ciic structure except as hereinafter claimed.
1. Inljcementing apparatus for oil wells, a disk adapted to be secured within the lower end of the well casing and having a large opening formed therein, a series of minute openings likewise formed inI the disk and a plug adapted to be placed upon the cement within the well and to engage with the disk to seal the large opening of the disk and lock the plugto the'disk.
2. In cementing apparatus for oil wells, a disk adapted to be secured within the lower end ofthe well casing and having a large opening formedvtherein, a series of minute openings likewise formed in the disk and a hollow plug adapted to be placed upon the cement Within the well and to engage with the disk to seal the large opening of the disk and lock the plug to the disk, said. plug being formed in its upper and lower ends with a series of minute openings.
3. In .cementing apparatus for oil wells,
a disk adapted to be'secured within the lower end of the well casing and having a large opening formed therein, a series of minute openings likewise formed in the disk andv a plug adapted t0 bepplaced uponthe cement wlthin the well having at its lower end means adapted -to pass through the openingoi' the disk when the plug comes into contact with the disk and to seal the disk at the unv der surface thereof.
4. In cementing apparatus for oil wells, a disk adapted to be secured within the lower end of the well `casing and having formed therein an opening for the passage of cement and other openings permitting the passage of Huid but preventlng the passage of ce,y
Lucano@ ment and a plu adapted to be placed upon the cement and aving engagement with the disk sealing the first named opening.
5. In cementing apparatus for oil Wells, a disk adapted to be secured Within the lower end of the Well casing and having formed therein an opening for the passage of cement and other openings permitting the passage of fluid but preventing the passage of cement and a plug adapted to be placed upon the cement and having engagement withl the disk sealing the first named opening and locking the plug to the disk.
6. A plug for use in cementing oil wells adapted to be placed upon the top of the 'cement Within the Well, said plug being of less diameter than the internal diameter of the casing and having projecting outwardly therefrom a circumferential bristle clump the bristles of Which are adapted to engage against the interior Walls of the casing to remove adhering cement therefrom.
ln testimony whereof I hereunto affix my signature.
WILLIAM T. THOMAS.