US1937247A - Device for cementing wells - Google Patents

Description

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Nov. 28, 1933. 1 A RlTTER DEVICE FOR CEMENTING WELLS Filed May 11, 1929 Patented Nov:3 2%, H9333 Jobin Ai. Ritter, Dallas, Tex., Misterios to Sun @il (Company, Plailadeipbia, Pa., a corporation ci New Jersey Application May lll, MEQ. Serial No. 362,21

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Tliisvinvention relates to the art ci cementing casings in wells and particularly relates to a plug adapted to be used in connection with such cementing.

ln the casing method of cementing casings in cil or other wells, it is customary to lower witi'iin t'ne casing first the bottom plug, tnena charge of cement and a top plug, the combination being pressed downwardly to the lower end or the cas'a ing by pumping above the top plug water or mud under pressure so as to force the plugs and cement downwardly, thereby pressing the cement upwardly around the outside of tbe casing and sealing tbe bottom within tbe bore hole. It is found tliat frequently a pocket oi air is carried down between the cement and the top plug, tiiis pocket of air being forced downwardly when the top plug approaches tbe bottom and upwardly outside tbe casing, causing a destruction ci the'. continuity oi tbe cement by reason ci air bubbles therein.

lit is the object ci tire present invention to prom vide means for automatically removing a pocket ci air which may be entrapped above tbe cement, which is further adapted to prevent the upward passage ci cement citer tbe air pocket .Tries been removed.

ln tbe drawing:

l is vertical section through a bore bolo t and casing therein, snowing tbe operation ci tbe improved device; 1

Fig. 2 is a vertical sectional view of a top plug made in accordance with this invention; and

Fig. 3 is an enlarged sectional view ci a onecle. valve used in tbe top plug.

Referring to -Fig. i, the bore ."ncle of an oil well is indicated et 2. Within this bore Ibole is lc-l cated, as is customary, a casing l extending down-n wardly to a position adjacent tlie bottom of tbe core cole, this casing being surrnounted by a removable cap 6. in cenienting tbe casing in position in tbe bore liole, a lower plug 8 is rst inserted in the casing. Above this plug is then inserted a charge 10 of cement suiicient for the purpose oi lling up the space between the lower 'portion ci the casing and the side walls ci the bore bole. A top plug l2 is inserted above the charge of cement. Because of the weight of the charge of cement, the cement and lower plug usso ually move to a position intermediate the top and bottom of the casing, so that the top plug 12 rnust drop a considerable distance before approaching the top oi. the cement. Inasrnuch as f the top plug has a substantially air-tight contact 55 with the walls of the casing, it will serve to compress a pocket of airl between itself and the top of the column of cement. The plug of the present invention permits the escape of such air, as will be later described.

The plug l2 comprises a central skeleton porn tion 13 ci light wooden construction adapted to permit its ready destruction upon continuation of the drilling. This skeleton portion 13 carriesY upper and lower discs le and 16, which are pro-z vided with leather washers arranged to maintain the plug in proper position relative to the walls te of the casing. A leather or composition cup carried by a top disc lies in substantial liquidI tight contact with the walls of tbe casing, so as to prevent the passage of liquid from one side of tice plug to the other.

Extending through the upper disc ifi is a vent tube 2) surmounted by a cbeclr valve 22 ci form shown in Fig. 3, 'this check valve being provided with an annular seat 2o on which a valve Re rests, the valve nier-ober being pivoted at 28. A cap 3G may close tire side of the valve 22 permitting removal ci tice valve member 26.

Assuming the parts to be in tbe positions shown in Fig. i, during the cementing ci a weil n inud or water 32 will be introduced under pressure tiirougb tire pipe Sei, serving force downwardly tlietop plug l2 and through tne medium thereof the column oi cement and tbe bottoni plug in air Vpocket 36 may, during this process, be enn trapped between the top plug and the cementu The air may freely pass about the lower disc 13 of the top plug and. passes upwardly through onecle valve 26, tbe pressure on the lower side oi which will be slightly greater than the pressure on the upper side, thereby permitting its opening. The escaping air will bubble tiirougbL the water 32. When all of the air escapes, any. cement whiclipasses upwardly to the valve will fail to pass through the same and tire valve will auto 9" matically close by reason of the fact that tbe plug is now resting upon the cement and the prese sures on the upper and lower faces of the valve are substantially the saine, inasmuch as there is liquid on both sides. Accordingly, intermixture of the' water or mud above the plug with the cem :ment therebeneath will be prevented, passage of the water downwardly through the check valve being positively prevented by its closure and there being no tendency for passage of cement upwardly because o t the reasons above mentioned.

It will be obvious that the specic type of check valve may be replaced by many equivalent types and accordingly it is not desired to limit the 110 c1 to the speelde menne disclosed for eiectim the results described.

Wheat l claim und desire to protect nv lettere Petent is:-

l. l device for cementing `veils inclu n. plus erreneed to pass through e well cuisine' eloove n cher-ge of cement und including n body, n lower washer-secured to the body, en upper washer or cupped shape secured to the body und adopted to engage the wells or e, casing, und en upwur opening check vulve controlling n pesseee be tween the upper und lower sides ci the upper wesloer. l v

2. A device for cernc-:ntirurr wells inclu e plug arranged to ps through n well casing nuove e charge of cement und including n body, n washer secured to the body end adapted to engcge the wells of e cursing to close the cesine, end en up= werdu opening check vulve controllinf,r n pessege between the upper end lower sides of the washer.

il.l A device tor cementing wells including u plug munged to pees through c Well casing alcove n charge or cement, und ineens ellowm the pes=1 enge o entr-upped dir upward peut the plug while preventine7 the upward pessuge o cernent,sei.d

member und e, sect tnereor .so related that the vulve `will open und pees er when the plug is subjected to hydraulic pressure from nuove.

4. A method of cementing wells including locating Within e `Well cesingf e emerge of cement, lowering within the casing' nuove the cement e plug provided with ineens allowing the passage of entrepped nir upward pest the plug while the plug is, subjected to hydruulic pressure from shove but preventing the pnssepe o cement, und applying hydraulic pressure above the plus to force the cement downwardly wit the cnsing.

5. l method of cenrentinz';7 wells including locuting within e well casing n cherge of cement, lowering Within the cursing elcove the cernent e plug provided with e check vulve lsllovfine; the passage ol entrepped nir upward pest the plug while the plug is subjected to hydraulic pressure from shove but preventing time pesscge ci cement, end epp hydraulic pressure ebove tire plug lto iorce time ceent dovrrnwerdli Wl il A f. the curing.

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