US2169568A - Apparatus for multiple stage cementing - Google Patents

Description

Aug. l5, 1939. o. L.. MoRRlsETT APPARATUS FOR MULTIPLE STAGE CEMENTING Filed Apil 2, 1958 INVENTOR. 0.L./70r'7''se it.

ATTORNEYS.

Patented Aug. 15,1939

UNITED STATES APPARATUS FOR MULTIPLE STAGE CEMENTING O. L. Morrisett, Duncan, Okla., assignor to Halliburton Oil Well Cementing Company, Duncan,

Okla.

Application April 2, 1938, Serial No. 199,575

Claims.

This invention relates to the cementing of oil` wells or the like and more particularly to an arrangement for cementing long strings -of casing or pipe in stages so that all of the cement 5 which fills the annular space around the casing may be supplied thereto without passing around the bottom of the casing.

The multiple stage cementing of wells is now well known to those skilledin the art. A method and apparatus for accomplishing this is fully disclosed in the United States patent to Halliburton, No. 1,860,669, granted May 31, 1932, and in the reissue thereof, No. 19,570, reissued May 14, 1935.

In the multiple stage cementing of wells a valve structure, usually called a multiple stage unit, is made up with the casing. The arrangement is such that at the proper time the valve in this unit is opened so that cement can flow outwardly therethrough to the annular space surrounding the casing. The valve may be a sleeve valve, as taught in the patents mentioned above, and may be opened by one of the cementing plugs used in the multiple stage cementing operation. Y

As taught in the above-mentioned patents, apparatus for multiple stage cementing of wells may involve similar multiple stage units, one made up above another with the casing, each multiple stage unit having a sleeve with a different size inner shoulder or restriction so that plugs of different sizes can move the sleeves with which they respectively cooperate. ,y

It is obvious that if the cement is to be discharged only at the bottom of the casing and at some point above the bottom, only one multiple stage unit need be employed, the cement being first forced out through the bottom of the casing and then out through the multiple stage unit. In some cases, however, especially in very deep wells, it may be necessary or desirable to force the cement not only out at the bottom of the casing but also out at two or more points above the bottom. When such a system is used, two or more multiple stage units must be employed and selective means must be provided for opening the multiple stage units in the proper sequence. Selective actuating means must also be employed Where a multiple stage unit is used in combination with a full hole cementing unit such as is commonly employed near the bottom of a well. What is referred to as a full hole cementing unit is disclosed in the patent to Manning, No. 1,684,551, granted September 18, 1928, for Cementing apparatus.

In the co-pending application of R. E. ODonnell, Serial No. 112,950, led November 27, 1936, for Multiple stage cementing, apparatus em ploying male and female plugs is shown and described for use in connection with the multiple 5 stage cementing of oil wells. In accordance with the present invention it is proposed to use male and female plugs somewhat similar to those described in the ODonnell application for use in connection with apparatus requiring that the casing be opened at more than one point or stage.

Now in accordance with the present invention it is proposed to employ male and female plugs like that disclosed in the ODonnell application for actuating a plurality of multiple stage units or for actuating one or more multiple stage units in connection with a full hole unit.

It is one object of the invention therefore to devise novel means and methods for opening ports in a casing of an cil well at a plurality of points therein.

It is a further object of the invention to devise apparatus and methods for multiple stage cementing of a well in which a male and female plug are employed for opening ports in the casing of the well.

Other objects and advantages reside in certain novel features of the arrangement and method as will become more apparent from a consideration of the following description talien in connection with the accompanying drawing, in which:

Figure 1 is a vertical cross-sectional view of an oil well with casing therein, the casing being provided with a multiple stage unit and a full hole unit and cooperating apparatus illustrating one embodiment of the invention, the parts being in the position which they occupy before either multiple stage unit or the full hole cementing unit shown has-been opened;

Figure 2 is a vertical cross-sectional view of the same apparatus as that shown in Figure 1 but illustrating the position of the parts after cement has been discharged through the full hole cementing unit and is being discharged through th-e multiple stage unit;

Figure 3 is a vertical cross-sectional View of an oil well with apparatus therein illustrating another embodiment of the invention, this' arrangement employing two identical multiple stage 50 units,'the parts being shown in the position which they occupy before cement has been discharged from either unit; and v Figure 4` is a vertical cross-sectional View of the arrangement of Figure 3 but showing the po- 55 sition of the parts after cement has been discharged from the lower multiple stage unit and as it is being discharged from the upper multiple stage unit.

Referring to the drawing in detail and first to the embodiment illustrated in Figures 1 and 2, it will be seen that an oil well is therel illustrated at II, the well being provided with casing I2 which is to be cemented within the well. The lower end of the casing may be provided with a perforated section I3 which is not to be cemented. A

Made up with the casing are two units through which cement may be discharged, the upper one of which is designated I4 and the lower one of which is designated I5. The unit I4 is generally referred to as a multiple stage unit and includes a collar or a casing member within which a sleeve I6 is slidably fitted, the sleeve being held in position by means of shear pins I1 and normally covering ports within the collar such as are shown at I8. These ports may be provided with check valves or other closing means which will prevent fluid flowing inwardly therethrough in accordance with-known practice. The arrangement is such that when the pins I1 are sheared and the sleeve I6 moved downwardly the ports I8 will be opened so 'that cement may be discharged therefrom. As means for forcing the sleeve downwardly, inwardly extending flange or seat I9 is provided, which seat is adapted to be engaged by a cooperating section on one of the cementing plugs as will .presently be described;

The lower discharge unit which is referred to as a full hole unit I5 is somewhat similar to the multiple stage unit just described. It includes a collar provided with ports 20 which Vare initially and normally closed by means of a sleeve 2| which is held in position by means of shear pins 22. The sleeve 2I has an inwardly extending ilange 23 which is provided with a central opening 24 through which fluid may flow downwardly. The flow of fluid upwardly through the opening 24 is prevented by means of a check valve 25 held in position by means of a cage 26.

Also made up with the casing at any convenient point between the multiple stage unit I4 and the full hole cementing unit I5, but preferably immediately below the multiple stage unit, is a female plug 21 which may consist of a body of wood to which flanges or cups of rubber are secured as illustrated and which is provided with a shearable ring 28 fltted into one of the collars of the casing. The female plug 21 is provided with a central opening 29, as illustrated.

The parts just described are made up with the casing before it is lowered into the well. Additional apparatus which yis used in the cementing operationgincludes a male plug such as is shown at 30 in Figure 1, this plug consisting of a wooden body provided with flanges or cups of rubber or fabric such as are illustrated at 3I. The lower end of the plug 30 is provided with a depending guiding pin 32 and with a valve body 33 adapted to engage the corresponding shaped valve seat on the plug 21 so that when these twoplugs are engaged a tight seal is effected therebetween. The valve 30 is so designed as to pass freely through the multiple stage unit I4 without affecting it in any way whatsoever.

As the plug 30 is forced downwardly beneath a body of cement it engages the plug 21 and passes downwardly therewith after the shearing of the ring 28 until the flange 23 of the sleeve of the full hole cementing unit is encountered, at

which time the pins 22 will shear, forcing the sleeve 2I downwardly and opening vthe ports 20 so that cement can flow outwardly therethrough. At this time the parts are in the position shown in the lower portion of Figure 2.

It is common but not essential to employ what is usually referred to as a No. 2 plug which follows the lower batch of cement. If such a plug is used it should be of the type shown at 34 in Figure 2 and consist merely of a wooden body provided with rubber flange members and which is sc designed as to pass freely through the multiple stage unit. I After the cement is forced outwardly through the full hole unit a second batch may be forced out through the multiple stage unit which is operated by-plugs such as are usually employed for that purpose and which in the present arrangei ment are designated 35 and 36, respectively. The second batch of cement may be pumped downwardly at the same time that the first batch is pumped down, being separated by a suitable quantity of mud or other fluid, or the multiple stage unit may be opened by the plug 35 as the rst batch of cement is forced outwardly through the full hole cementing unit and mud or other fluid circulated for some time or even until the first batch of cement has become hardened before the second batch of cement is forced downwardly into the well and out through the multiple stage unit.

The operation of the multiple stage unit will be clear from what has been said above and from a study of the Halliburton patents mentioned above, it being obvious that when the plug 35contacts the inwardly extending flange or seat on the sleeve I8 the ports I8 will be opened and permit the discharge of fluid outwardly therethrough'. The'second batch of cement is followed by a top plug 36 in accordance with known practice.

The embodiment of the invention shown in Figures 3 and 4 is the same in construction and operation as that shownin Figures 1 and 2, except that two multiple stage unitsare illustrated instead of one multiple stage unit and a full hole unit. In Figures 3 and 4 the upper multiple stage unit is designated 31 and the lower one 38. These are identical in construction with each other and with the unit I4 shown in Figure land described above. For this reason the units 31 and 38 will not be described here in detail.

yBetween the multiple stage units 31 and 38a female plug 39 is secured to the casing. This' plug ls identical with the plug 21 shown in Figure 1 except that it is provided with a valve seat 40 at its lower end adapted to cooperate with the inwardly extending flange or ring 4I on the sleeve of the lower multiple stage unit 38.

During the cementing operation the arrangement of Figures 3 and 4 a male plug 42 is employed, this plug being identical with the vplug 30 shown in Figures 1 and 2. Upon the plug 42 contacting the plug 39 the ring which supports the plug 39 shears and the plugs 39 and 42 move downwardly through the casing until the ring 4I is encountered, at which time the pins in this multiple stage unit shear, opening the ports there.- in so that the lower batch of cement can be discharged outwardly therethrough. The parts in the lower multiple stage unit 38 then take the position shown in Figure 4.

The lower batch of cement in the arrangement of Figures 3 and 4 may be followed by a plug 43 which is the same as the plug 34 in the arrangement of Figure 2 and the operation of the multiple stage cementing unit 31 is the same as the operation of the unit I4 in Figures 1 and 2.

From the above description it will be seen that a plurality of multiple stage units or one or more multiple stage units in combination with a full hole unit can be operated by means constructed in accordance with the principles of the invention. If more than two multiple stage units are to be employed, two or more female plugs such as those shown at 21 and 39 may be employed, each having different size openings and the apparatus including two or more male plugs such as those shown at 30 and 42, these being of different sizes to properly cooperate with the female plugs.

The use of male and female plugs in addition to operating the lower unit, whether the lower unit be a multiple stage or a full hole unit, has the advantages pointed out in the ODonnell application cited above. The flanges on the female unit may be made of aluminum or other drillable, but inflexible, material so as to scrape the walls of the casing as it moves downwardly therein, as is pointed out and specifically claimed in the aforesaid QDonnell application While only two embodiments of the invention haveI been shown and described herein, various changes may be made in the arrangement and method without departing from the spirit of the invention or the scope of the annexed claims.

I claim:

l. Apparatus for use in the multiple stage cementing of a casing in a well, including in combination with-the casing, an upper and a lower unit made up with the casing at spacedl points therein, each unit having ports for discharging cement or other fluid therethrough and meansy normally closing said ports, a female plug releasably securedv in the casing between said units, a male plug adapted to engage said female plug to cause the same to be released from the casing under the influence of fluid pressure, whereby the male and female plugs may move downwardly to contact and move the closing means in said lower unit to open the ports in said lower unit under the inuence of fluid pressure, and an additional plug adapted to cooperate with the closing means in upper of said units to operate the same to uncover the ports therein under the influence of fluid pressure.

2. Apparatus for use in the multiple stage cementing of a casing in a well including, in combination with the casing, a unit made up with the casing, said unit having ports therein for the discharge of cement or other fluid there-y through and means normally closing said ports, a female plug releasably secured in the casing above said unit, a male plug movable freely in said casing and adapted to engage said female plug to cause the same to be released from the casing under the influence of fluid pressure whereby said male and female plugs may move downwardly to move the closing means therein to open the ports under the influence of fluid pressure, upon said plugs contacting said unit.

3. Apparatus for use in the multiple stage cementing of a casing in a well including, in combination with the casing, a unit made up with the casing, said unit having ports therein for the discharge of cement or other fluid therethrough and means normally closing said ports, a plug releasably secured in the casing abovesaid unit and having an opening therein adapted to conduct fluid therethrough while secured to said casing, a second plug adapted to cooperate with said first mentioned /plug to seal said opening whereby said first mentioned plug may be released froxn the casing upon fluid pressure .being exerted upon said plugs jointly, whereby said male and female plugs may move downwardly tovmove said closing means to open said ports under' the influence of fluid pressure, upon said plugs contacting said unit.

4. Apparatus for use in the multiple stage cementing of a casing in a well, including, in combination with the casing an upper and a lower multiple stage unit of identical construction, each unit havingports therein and means normally closing said ports, a plug having an opening therein releasably secured in said casing between said' units, a second plug adapted to seat upon said first mentioned plug to release the same upon fluid pressure being exerted thereon jointly, thereby causing the aforesaid plugs to move downwardly and operate the closing means in the lower lof said units to open the ports therein and a third plug adaptedto operate the closing means in the upper of said units to open the ports therein. l

5. Apparatus for use in the multiple stage cementing of a casing in a well, including in combination with the casing,an upper and a lower full hole cementing unit, each unit having ports therein and means normally closing said ports, a plug having an opening therein releasably secured in said casing between said units, a second plug-adapted to seat upon said first mentioned plug to release the same upon fluid pressure being exerted thereon jointly, thereby causing the aforesaid plugs to move downwardly and operate the closing means in said full hole cementing unit to open the ports therein and a third plug adapted to operate the closing means in said multiple stage unit to open the ports

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