US2438992A - Well cementing apparatus - Google Patents

Description

April 6, 1948. R. o. CHILDERs WELL CEMENTING APPARATUS 2 Sheets-Sheet l Filed Apr'i1` s, 1942 05605 0. CHM of@ INVENTOR.'

TTORNEY April s, 1948.

R. o. cH'lLDERs WELL CEMENTING APPARATUS Filed April 5, 1942 2 Sheets-Sheet 2 Roscoe' 0. TH/1.95@

INVENToR.

l. @MM/V 4ATTORNEY Patented Apr. 6, 1948 WELL CEMENTING APPARATUS Roscoe 0. Childers, Olney, Ill., assignor to Baker Oil Tools, Inc., Vernon, Calif., a corporation of California Application April 3; 1942, Serial No. 437,545

(Cl. MiG- 1) 12 Claims.

This invention relates to the cementing of casing in well bores, and is more particularly concerned with the cementing of long strings of casing by ejecting separate charges of cementitious material therefrom at predetermined longitudinally spaced points along the well bore.

In drilling and completing many wells, it is usual practice to cement the casing in the well bore along its entire length in order to prevent migrant waters from contaminating the Well fluids. In deep wells,` it is diiiicult to perform this operation with a single charge of cement slurry ejected from the lower end of the casing, because of the high pressures required to elevate the slurry in the annulus around the casing to the desired level, and the time consumed, which might allow quick acting cement to set prematurely.

It has been proposed to avoid these difculties by cementing the casing in the well bore by stages. ejected from spaced predetermined points along the casing in upwardV sequence until the entire length of the casing is surrounded with the desired sheath of cement. The casing outlets above the lowermost of these predetermined points are initially closed, as by an internal slidable sleeve Valve, and plug devices are employed for opening them at the proper time and sequence. These plug devices not only function to open the sleeve valves, but they also operate as separting elements` between each charge of cement slurry and mud, to prevent their com-mingling and consequent contamination of the slurry.

The plug and sleeve valve arrangements heretofore used have been of such character and cooperate in Such manner as to require the introduction of all plugs and charges of cement slurry separated by predetermined quantities of drilling mud in a single continuous operation in the well casing If errors are made in the extent of the mud column intervening between separate charges of slurry, an upper sleeve valve would be opened by a plug prematurely,` or it would be impossible to open it at all, precluding ejection of the cement slurry in the casing above the mud column. In addition to this diii culty. such plug and sleeve valve arrangements do not permit washing fluid to he circulated through the outlets of a particular stage prior to the cementing of that stage.

The aforementioned diflicultes have been overcome by an apparatus described and claimed in the application of Reuben C, Baker, Serial No. 434,913, led March 16, 1942, now Patent #2,370,-

That is, separate charges of cement` are 833, dated March 6, 1945, for Apparatus for cementing well bores, in which the cement slurry and following mud column of fluid are introduced in the well bore with an intervening flexible top cementing plug. This plug is made of a material which permits its slida-ble engagement with the well casing and radial compression and passage through a sleeve valve bore of materially restricted diameter as compared to the inside diameter of the casing string. Afterl passing through the sleeve valve, the plug expands to its initial shape so as to continue functioning as a top cementing plug in forcing the cement slurry ahead of it down through the casing for ejection therefrom at a predetermined lower point. Following completion of the cementing operation at the lower stage, a bridging member is allowed to gravitate through the mud fluid in the casing into engagement with a companion seat in the sleeve valve to close its central passage, allowing the sleeve Valve to be shifted downwardly by hydraulic actilon to a position opening lateral ports through an upper cementing Stage, This upllerv stage could then be Washed thoroughly by circulating ui'd and placed in condition for the reception of the requisite quantity of cement slurry .pumped down the casing string for ejection through the open ports.

It is an object of the present invention to provide an improved multiple stage cementing apparatus in which charges of cement slurry can be ejected from the well casing at predetermined points independently of one another, and in which the outlets at such points are closed by sleeve valves having a larger central bore than heretofore employed, to permit easier passage of cementing plugs therethrough, and diminishing the danger of inadvertent shifting of the sleeve valves by the plugs to port opening positions. Despite the employment of a sleeve valve having a central passage that is not much smaller than the inside diameter of the casing string, the apparatus still permits the use of `a bridging member capable of gravitating to a companion seat on a device associated with the Sleeve valve, so that the latter may be hydraulically shifted to open position after the cementing operation through a lower stage has been completed.

The invention is also concerned with an improved top cementing plug capable of separating charges of cement slurry and following drilling mud yduring their entire passage through the casing String, and of passing through a sleeve valve closing upper stage ports without shifting such sleeve to open position.

Another object of the invention is to providey an improved top cementing plug of a composite construction, in which the lower portion or member of the plug is effective to separate cement slurry and a following column of mud or other fluids throughout the entire travel of the cement slurry through the casing, and in which an upper portion of the plug travels only part way through the casing string until it reaches a sleeve valve, where it becomes separated from the lower plug portion.

This invention has other objects which will become apparent from a consideration of the, apparatus shown in the drawings accompanying and forming part of the present specication. This apparatus will now be described in, detail to illustrate the general principles of the invention, but it is to be understood that suchdetailed description is not to be taken in a limited sense, since the scope of the invention is best dened by the claims appended hereto.

Referring t the drawings:

Figure 1 is a longitudinal section through a casing string embodying the apparatus of the present invention, with a top cementing plug above a stage collar with which it is to cooperate; Y

Figure 2 is a view similar to Figure 1, with the lower part of the plug shown below the stage collar; Y

Figure 3 is a view similar to Figure 1, disclosing the upper part of the plug after it has effected opening of the stage collar;

Figure 4 is a longitudinal view on an enlarged scale of the plug portion of the apparatus within the stage collar; and

Figure 5 is a view similar te Figure 4 of anotherV embodiment of the invention.

The same reference numerals refer to like parts throughout the several views 'and embodiments of the invention.

In its general aspects, the invention is directed to a well cementing apparatus including a top cementing plug capable of separating cement slurry and a following mud column throughout the entire length of travel of the slurry through a well casing string, and which is alsocapable of opening an upper sleeve valve in the casing string after completion of a cementing operation at a lower stage,

The plug is of such character as to permit the stages to be cemented separately and independently of one another, and it also permits the use of a sleeve valve having a central bore almost as large as the inside diameter of the casing. The cementing plug is made of two main parts with the lower portion capable of passing readily through the sleeve valve, which arrests the upper portion, whereupon the pressure of the iiuid above the plug disconnects the lower portion from the upper portion and permits its continued downward travel through the casing below the sleeve valve as an efiicient top cementing plug in preventing contamination between the cement slurry and mud in the well casing. The two plug members are disconnected at the sleeve valve with the exertion of a separating force that is too low to shift the sleeve valve to port opening position.

The upper plug portion is provided with a central passage of much less diameter than the internal diameter of the casing string, to permit use of a bridging member that Yis small enough to gravitate readily through the uid in the casing above the sleeve and close its bore, allowing an increase in the pressure of iiuid above the upper plug portion to shift the sleeve downwardly to port opening position, and permit the upper stage to be cemented.

The form of invention disclosed in Figures l to 4, inclusive, consists of a tubular collar Ii) adapted to form part of a casing string by being threaded at its opposite ends to upper and lower casing sections II, I2, or to an intervening coupling. This collar is provided with lateral ports or outlets I3 through which fluids may pass from the interior of the casing string into the annulus between its exterior 'and wall of the bore hole. Although not essential to the present invention, if desired, return flow of such fluids is preventable .by any suitable back pressure valve device, which in the present instance consists of a flexible sleeve 'valve Ill of rubber or similar material whose lower end is fixed to the exterior of the collar and whose remaining upper portion is free to ex outwardly away from the ports I3 under the iniiuence of fluids passing therethrough. Any tendency for such vfluids to flow back through the ports is prevented by the rubber sleeve I 4 snugly embracing the ported collarparea.

The action of the flexible sleeve valve i4 can be supplemented by a plurality of closely spaced longitudinal leaf springs i5 extending circumferentially therearound. The lower ends of thesev springs are welded to the collar below the lower end of the exible sleeve I4, and the spring portions extending upwardly from this point of attachment to the collar project over and engage the flexible sleeve valve to add its spring action to the inherent elasticityA oi the flexible sleeve tending to hold it in closed position over the ports I3. It is therefore necessary for the fluid under pressure within the casing string to overcome both the elasticity of the rubber sleeve valve I4 and leaf springs I5 in opening the ports.Y

Not only do the leaf springs assist in the functioning of the rubber sleeve as a back pressure Valve, but they also serve to protect it against damage during lowering of the casing string in the well bore.

Passage of iiuids through the ports I3 is controlled by a sleeve valve I6 slidable within the collar. This valve is initially held over the ports by frangible means, such as shear screws I'I, which position its upper and lower side seals I8, I9 on opposite sides of the ports to prevent iiow of fluids in either ydirection between the exterior of the sleeve I6 and wall of the collar IQ for passage outwardly through the ports I3. The sleeve valve I6 is incapable of moving upwardly from the position in which it is held by the shear screws by engagement of its external shoulder 2l) with a companion shoulder 2i in the interior of the collar. When the screws I1 are sheared, in a manner hereafter described, the sleeve valve I6 is shifted downwardly to a position below the ports I3, limited by engagement of the lower end of the sleeve with a suitable stop, which is disclosed in the drawings as being constituted by the upper Aend of the lower casing section I2.

The collar and sleeve lvalve construction are incorporated in the casing string at a predetermined point along its length for operation as a multiple stage cementing device. That is, it is rst desired to eject cement from a particu-A lar point in the casing below this stage collar, "and after this lower cementing operation has been completed, to shift the sleeve valve I downwardly to open its cooperable ports I3 and permit the cementing operation to occur through them. It is also desired to eject the different charges of cement slurry separately and inde- Instead of forming this member entirely of a readily eompressible material, it isfo'rmed of a body 45 having a iiexible wiper disc 46 at its lower end secured to the body by screws 41 or the like. The upper portion of the body has a packing member 43 molded to it which extends across its upper end and has a depending skirt 49 terminating in a ilange '50 cooperating with an inturned flange I on the body to lock the packing member thereto. This packing member 48 is also furnished with an upwardly projecting flange portion 52 interlocking with the flange 53 at the lower end of the upper body member, in the same manner as was described in connection with the other form of invention. A peripheral packing member lip 54 extends outwardly for slidable sealing engagement with the wall'of the casing as the plug 24 passes through it.

The plug is used in exactly the same manner as the one previously described, The lower body 45 is small enough to pass freely through the sleeve valve It. This is also-true of the wiper disc 46 whose outer margins are deflectable upwardly by the sleeve valve as permitted by the relieved bevel portion 55 at the lower end of the body; and the lip member 54 is also -forced inwardly by the sleeve valve for passage therethrough.

When the shoulder 39 onthe upper plug member 23 engages the sleeve Valve It, its downward movement is stopped, and the pressure of the uid in its passage 4e disengages the interlocking flanges 52, '53 and forces the lower member 23 completely through the sleeve valve, whereupon the wiper disc 4S and packing lip 54 may again expand outwardly into slidable sealing engagement with the casing and continue to function as a top cementing plug in forcing the charge of cement slurry ahead of it through the casing.

It is therefore apparent that the present invention provides an improved apparatus for cementing each stage separately and independently of any other stage. The ports through an upper stage need not be opened until after the cementing operation through a lower stage has been completed, whereupon the upper stage can be thoroughly washed or otherwise fully conditioned prior to receiving its charge of cement slurry.

Iclaim: e

1. Apparatus of the character described, including a tubular member adapted to form part of a well casing and having a lateral outlet, valve means initially 4closing said outlet, an upper member having a passage therethrough and adapted to operate said valve means to open said outlet, a lower member, means releasably securing said upper and lower members together for joint movement downwardly through said casing until said upper member engages said valve means to arrest downward movement of said upper member, said releasable means being releasable to disconnect said lower memberv from said upper member after the latter engages said valvemeans to allow continued downward movement of said lower member below said sleeve valve in slidable sealing engagement with said casing, and means for closing said upper member passage to allow hydraulic pressure to be exerted on said upper member to move said valve means to outlet opening position.

2. Apparatus of the character described, including a tubular member adapted to form part of a well casing and having a lateral outlet, a sleeve Valve within said member initially closing said outlet, a cementing plug movable downwardly through said casing and comprising an upper member having' a passage therethrough and a lower member, means releasably securing said upper and lower members together during their downward movement through said casing toward said sleeve valve, said upper member being engageable with said sleeve valve, said means being releasable to disconnect said lower member from said upper member after engagement of the latter with said sleeve valve to permit said lower member to be moved through'said sleeve valve and slidably engage said c asing below said sleeve Valve, and means adapted to be sent down said well casing to close said upper member pas'- sage and allow hydraulic pressure to be exerted on said upper member and sleeve valve to move said sleeve valve to outlet opening position.

3. Apparatus of the character described, including a tubular member adapted to form part of a well casing and having a lateral outlet, a sleeve valve within said member for closing said outlet. a plug device comprising upper and lower members initially secured together and movable downwardly through said casing, said upper member having a fluid passage therethrough and being arrested upon engagement with said sleeve valve, said lower member being disengageable from said upper member by hydraulic pressure exerted through said fluid passage and said lower memberbeing adapted for slidable engagement with said casing as lit moves downwardly there-V through below said sleeve valve.

4.,Apparatus of the character described, including a tubular member adapted to form part of a well casing and having a lateral outlet, a sleeve Valve within said member, frangible means initially holding said sleeve valve in closed position over said outlet, a plug device comprising upper and lower members secured to one another and movable downwardly through said casing in slidable engagement therewith, said upper member being arrested upon its engagement with said sleeve valve, said plug device being so constructed and arranged that said lower member is hydraulically 'disco'nnectablev from said upper member after its engagement with said sleeve valve in order that said lower member may move through said sleeve valve without disrupting said frangible means, and means adapted to be sent down said well casing for cooperation with said upper member to enable said frangible means to be disrupted hydraulically and said sleeve valve moved to outlet opening position.

5. Apparatus of the character described, including a tubular member adapted to form part of a well casing and having a lateral outlet, a sleeve valve within said member, frangible means initially holding said sleeve valve in closed posithrough said sleeve valve without disrupting said frangible means, and means adapted to be sent down said well casing to close said upper member passage whereby hydraulic pressure may be exerted on saidV upper member and sleeve valve to disrupt said frangible means and move said sleeve valve to outlet opening position.l

6. Apparatus of the character described, in-

cluding a tubular member adapted to form part of a well casing and having a lateral outlet, a sleeve valve within said member, means initially holding said sleeve valve in closed position over` said outlet, a plug device comprising an upper member having a passage therethrough and a lower member slidably engageable with said casing and secured to said upper member to close one end of said passage, said upper member being arrested upon its engagement with said sleeve valve and said lower member being hydraulically disconnectable from said upper member after such engagement so as to be hydraulically movable through said casing below said sleeve valve, and a bridging ball adapted to be sent down said casing to close said passage whereby said holding means may be rendered ineffective hydraulically and said sleeve valve shif ted to outlet opening position.

7. A plug device adapted for use in well cas ing, including an upper member having a fluid passage therethrough and a lower member, means releasably securing said lower member to a body portion of said upper member, said lower member having means thereon adapted for slidable sealing engagement with the wall of such well casing, said lower member having a body portion so constructed and arranged as to be passable through a bore ofl less diameter than the body portion of said upper member.

8. Apparatus of the character described, including a tubular member having a lateral outlet and adapted to form part of a well casing positioned in a well bore, a sleeve valve slidable within said member for controlling flow of fluid from within said member through said outlet, means adapted to be sent down said tubular member from the surface of said well bore for restricting the bore through said sleeve valve, and means adapted to be sent down said tubular member for closing the bore through said first-mentioned means.

9. Apparatus of the character described, in-

ld said sleeve valve to restrict the bore of the latter, and means adapted to be sent down said tubular member into engagement with said plug device to close its passage.

1G. A plug device adapted for use in well casing, including upper and lower members discon` nectably secured together, said upper member having a body portion provided with a central passage normally closed by said lower member, and said lower member having a body portion passable through a bore of less diameter than the diameter of said upper body portion.

11. A plug device adapted for use in well casing, including upper and lower members discon nectably secured together, said upper member having a body portion provided with a central iiuid passage normally closed by said lower member, said lower member having a body portion passable through a bore of less diameter than the diameter of said upper body portion, and said lower member having a packing thereon adapted for slidable sealing with the wall of such casing.

12. A plug device adapted for use in well casing, including upper and lower members disconnectably secured together, said upper member having a body portion provided with a central fluid passage normally closed by said lower member, packing means secured to said body portion for slidable sealing with the wall of such casing, said lower member having a body portion passable through a bore of less diameter than the diameter of said upper body portion, and said lower member having packing means thereon adapted for slidable sealing with the wall of such casing.

`ROSCOE O. CHILDERS.

REFERENSES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 2,295,822 Armentrout Sept. 15, 1942 2,291,371 Buchanan July 28, 1942 1,866,038 Johnson July 5, 1932 Re. 19,570 Halliburton May 14, 1935 2,327,092 Botkin Aug. 17, 1943 2,330,267 Burt et al Sept. 28, 1943 2,169,568 Morrisett Aug. 15, 1939

Images