US2162261A - Well cementing - Google Patents

Description

June 13, 1939. 4A LAYNE 2,162,261

' WELL GEMENTING Filed March 5, 1936 2 Sheets-Sheet l INVENTOR. I A. LAYN E ATTORNEYS.

June 13, 1939. 1 A. LAYNE WELL CEMENTING Filed March 3, 1936 2 Sheets-Sheet 2 E il ATTORNEYS atei-liked lune l 531i PATENT .OFFICE 6 Claims.

The invention relates to an improvement in the apparatus and mannerfof packing and cementing the lower end of a string of pipe in wells.

In positioning the string of pipe in a well it is often desirable to form a seal between the outside of the pipe and the well bore. To accomplish this, a packer may be provided around the outside of the pipe so that it may be expanded into contact with the wall of the well, or the usual practice is to pump cement through the pipe so that it passes around the lower end of the pipe and sets in position to form a seal. Both'of these practices are n ot entirely satisfactory because the packer may not form a seal because of the nature of the formation of the wall of the well, and the cement may not form a complete seal because in flowing yinto position it may form channels `and in this manner leave open areas so that a complete seal is not formed. Withi these conditions in mind it is one ofthe objects of the present invention to provide a double packer arrangement in which the packers will move longitudinally to some extent while being set so that there will be a compression of the material adjacent the packers so that a seal will be insured regardless of whether the packer engages the wall4 formation or th e cement. Y Another object of the invention is to provide an apparatus wherein two packers may be set in the well bore following the positioning of the cement, so that the cement may be compressed adjacent the bottom of the pipe by the lowerl packer and against the lower packer by the upper packer.

Another object of the 'invention is to -provide a packer on a string of pipe to`be vcemented so that the expansion ofthe packer will insure centering of the string of pipe in the well and the consequent uniform distribution of the cement about the pipe. y.

Another object of the invention is to provide a pair of spaced packers to confine the vcement therebetween and to prevent the cement from owing about the screen.

Other and further objects of the inventionwill be readily apparent when the following description is considered in connection with theaccompanying drawings wherein:

` Fig. l shows a central vertical secti of the device after it has been lowered into-the well bore and after cement has been pumped'therethrough at a time just `prior to the setting of the packers. l

Fig. 2 is a View similar to Fig..lbut showing 55 the device having been actuated to set the lowermost packer, but with the upper packer as yet unseated. i

Fig. 3 shows both packers set and in compression against the wall formation and against the surrounding cement. 5

Figs.l 4, 5, and 6 show vertical sections of the invention as applied to a full hole pipe and screen assembly where the screen is set with the pipe.

The well bore which has been drilled in the earth formation is indicated generally at 2 and 10 may be of any desired depth or size. It is desired to position a string of pipe 3 in the well bore. 'I'his pipe may be the usual string of Well casing, or in fact it may be any string of pipe which it is desired to locate in the well bore. This string 15 of pipe 3 will be lowered into the well bore in combination with an extension pipe 5 which may be connected thereto by means of the telescoping or sliding connection 6. This connection is formed by a coupling 1 which is threaded at 8 2O v or otherwise connected tov the lower end of the string or pipe. This coupling 1 is fitted about the extension 5 and is prevented-from sliding over the end` thereof by the shoulder 9 thereon. One .or more shear pins Il) may be provided to 25 normally retain 'the coupling 1 inthe position shown in Fig. 1. The extension 5 tends to support the packer assemblies as will be later de. scribed.

The extension 5 is provided with a shoulder 30 i2 which is arranged to provide a seat for a suitable packer` I4. This packer may be of any desired type or conguration, the usual `form of which constitutes wrappings of fabric about the support' in such a manner that when the packer 35 is collapsed it will expand radially as best seen in Fig. 3. 'I'he upper seat for this packing is a shoulder I5 on the coupling 1. The extension 5 may be of any desired length and may have additional sections of pipe such as I6 between its 40 upper and lower ends. The lowei` end is also arranged to carry a packer such as 2|) which is conned between the upper shoulder 2| on the \extension and the lower shoulder 22 on a coupling 24. The coupling 24 may remain stationary while 45 the extension is slidable therethrough in thesame manner as the coupling 1, so that it may move downwardly to cause setting of the packing 20. The enlarged end 25 prevents the coupling 24 -from sliding beyond the end of the extension 5.

Connected to the coupling 24 is a setting sleeve 21 which extends down ,below the end of the extension 5 and may be provided with a guide-shoe 28. This setting sleeve 21 is provided with a reduced portion 30 which is arranged to support 55 a breakout ring 32. This breakout ring may be of any suitable material which is fragile but which is arranged to be broken when contacted by any member such as the cement plug 33. This breakout ring has an opening therethrough to permit the passage of iluid. The lower end of the guideshoe 28 is open at 35 to permit the discharge of cement.

In operation the device will be lowered into the well bore, assembled as shown in Fig, 1. Ilk

cement is to be applied about the-lower end of the string of pipe 3 to form a seal, then the cement will be deposited in the pipe 3 and pumped downwardly by applying liquid pressure thereto. It is usual to place a cement plug 33 on top of the cement in the pipe. Liquid pressure is then applied to the column of cement and the plug to force it downwardly through the pipe. The cement will, of course, be discharged through the extension 5, the sleeve 21. and the guide-shoe 28, and out the opening 35 Awhere it will be compelled to move upwardly around the apparatus and about the pipe 3 as best seen in Fig. 1.

The cement plug 33 serves the purpose also of advising the operator when the cement has been discharged from the pipe because it moves downwardly to engage the breakout ring 32. As previously pointed out the breakout ring prevents telescoping movement between the extension 5 and the setting sleeve 21, but when the cement plug 33 engages the breakout ring liquid pressure applied thereto will break the ring so that it will move downwardly with the cement plug to the position shown in Fig. 2.

At the same time that the breakout ring is removed if all or part of the weight of the string of pipe 3 is applied to the apparatus the extension 5 will telescope into the setting sleeve 21. The coupling 24 will remain stationary as the extension 5 telescopes downwardly through it. This movement brings the shoulder 2| toward the shoulder 22 to expand the packing 20 so that it will move outwardly to engage the wall 2 of the well bore as best seen in Fig. 2.

It will be seen by this operation that the shoulder 22 remains stationary, whereas the shoulder 2| moves downwardly to perform a downward'movement of the packer during its expansion or setting. During this period the pressure is maintained inside the string of pipe and against the cement plug 33 so that therethe setting sleeve 21 and below the packer 20 is trapped in this area and is subjected to a compressive force by the downward expanding movement of the packer. If the cement plug 33 has merely broken the ring 32 but has not moved all the way down to the Fig. 2 position then the end 25 of the extension 5 will abut against the plug as the pipes are telescoped to set the packer. 'I'his contact will push the plug along ahead of the extension 5 and additional compression will be obtained by the continued movement of the cement plug v33 as it moves downward ahead of the pipe. In order that the plug 33 will withstand this pressure the top leather or seal ring 34 may be reenforced at 34'..

It seems apparent from this operation that the body of cement 40 around the lower end of the device may be subjected to a compression by the simultaneous movement of the packer and plug so that if it has channeled while it was being f positioned that the channels will be destroyed and the cement so disturbed and compressed that a positive seal will be created. When the plug 33 has passed below the bottom end of pipe 25 the cup leather 34 on top thereof will expand and thus the plug 33 is kept from moving back into pipe 5.

Another advantage of expanding the packer while the cement is liquid is that the pipe will be moved by the expanding packer to a central position. It is to be understood that a majority of well bores are not exactly vertical; many of them are inclined'up to 5 or 6 degrees so that when the casing is -lowered it slides along the low side of the bore. If. the pipe were in close contact with one side of the bore no cement would be deposited 'on that side. With the present arrangement, however, the expansion of the packer will lift the pipe from the low side of the bore to a central position. The liquid cement about the pipe being under pressure will be caused to flow in under the pipe as it is moved away from the side of the bore. In this manner a uniform distribution of the cement will be insured. Any channels which have formed will be destroyed and the cement forced rmly against the pipe and the wall of the well bore.

After the lower packer 20 has been set and the pipe centered it is then desirable to form an additional seal and compression of cement 50 between the packers I4 and 20.

It is intended that the shear pins II) will be so calculated and designed that they will withstand a shear force. to accomplish the setting of the lower packer 20 but will be of such a strength that when a force exceeding that required to set the packer 20 is applied to them they will shear and permit the setting of the upper packer I4. 'I'he extension 5 may telescope to the position shown in Figs. 2 and 3 and its further movement prevented because of the resistance to further compression of the packer 20.

If, however, the packer 20 expands a maximum amount, then the lower end 5I of the extension 5 may engage the shoulder 52 in the sleeve 21 so as to provide a denite stop for the extension. Regardless of whether this extension is prevented from downward movement by the stop 52 or by the compression of the packer 20, the shoulder I2 will remain stationary upon shearing of the pins I so that downward movement of the string of pipe 3 will move the coupling 1'downward and expand the packer I4 as seen in Fig. 3.

There' will be a certain Aamount of downward movement of the upper portions of the packer I4 while it is being set in this manner so that the body of cement 5I) which is trapped between the two packers will be subjected to a compressive force and insure thatany channels ,therein will be destroyed and that the cement will be forced against the wall 2 of the well. l

While the invention has been described in combination `with a cementing operation-it seems obvious that the double seal may be obtained when no cement is present if such a seal is desired. Under such circumstances any instrument may be dropped into the string of pipe 3 to destroy the breakout ring 32 to permit the setting of the lowermost packer in lieu of destroying the breakout ring with the cement plug 33.

f Figs. 4, 5, and 6 show a slightly modified form of the invention wherein the parts are substantially constructed and arranged Athe same as in the Fig. 1 form of the invention except that replacmg theguide shoe 28 is a coupling 60 which lor lli

' 5 and the packer support.

has' connected thereto any desired form of strainer or screen 6l. This screen nmay be of any desired length and will in turn have the guide shoe 2B attached to its lower end. When a screen of this type is embodied in the assembly it is usual to employ-a back pressure valve tito prevent an iniiow of sand or other material at the position of the screen.

,This assembly is known as a full hole assembly when the screen is lowered into the well bore at. the same time Vas the casing. This assembly may be used, however, ywhen the pipe 5 is the liner which is to be set in the lower end of a string of well casing. `In either instance, it is desirable to form a seal in the well bore above the screen to prevent the discharge flow of eX- traneous liquid and preventcaving in and around` the screen. In this manner the screenv is closed on so that it is only open at the prospective formation opposite whichV it has been located. i

With an assembly such as the foregoingthe present invention as described in connection with Figs. 1 to 3, inclusive, may be utilized by pro` coupling 66 whichiis the same as the coupling ll of Fig. 1. Y

It is through these ports that the cement will be discharged into the well bore outside of the pipe in order to form a seal.` r[he packers are assembled in lthe same relationship as they are in Fig. 1, but in Fig. 4 a bottom plug '61 has been inserted in the pipe below the body 68 of cement and this plug will be of suiicient length to contact the breakout ring 32 at its lower end while the upper endor sealing portion 69' thereof is at an elevation above theports 65 as best seen in Fig. 4.' With the ports in this position the cement cannot be discharged into the well bore until the ring 32 has been broken out by the' plug 61 and by-applying pressure to the body of cement 61 the ring 32 will be broken out and fall into the bottom of the screen as seen in Fig. 5. The plug tl, however, carries a shoulder 'I0 which is arranged to abut against a stop ring 'Il in the lower end of the extension 5, so that the plug El will remain in the position shown in Fig. 5. 'I'he nose l2 of the plug 6l causes thev breakout ring 32 to be ruptured and this nose is of a size to pass through the opening in the stop collar l i. It will be noted in Fig. 5 that the upper endv 69 of the plug has moved below the elevation of the ports 65 so that the weight of thel string of pipe is lowered onto the packer 2li to eiect its expan-` sion as the cement begins to discharge when the ports t5 are uncovered, the packer being setby the telescoping lmovement between the extension In this manner the upper portionof the packer will be bathed in cement as it is set in position and the cement will then ow outwardly and upwardly as best seen in Fig. 5 to any desired elevation -depending upon how much cement is to be positioned.

The top plug 33 is seen in Fig. 6 as having moved down through the pipe the same as described in connection with Fig. 1 and advises the operator thatl all of the cement has been discharged when it abuts against the *top'of the plug til.v The operator can now lower such additional weight onto the pipe as may be necessary in order to shear the pin. l@ in order to release the upper packer it, the same as described `in connection with Fig. 1.

It will be apparent from the foregoing that an arrangement has been provided whereby a suitable body of cement can be discharged above vision' of a positive double seal about the lower end of a string of pipe and the compression of the liquid which is about the pipe Aat the time the packers are being set.

What is claimed is:

1. A method of sealing a pipe in a well bore which comprises the steps of pumping cement through the pipe ahead of a cement plug so that it discharges about the pipe and around a packer on the pipe, maintaining ,pressure on the cement plug to release the packer, and setting the packer by telescoping the pipe so as to compress the cement between the packer and plug and about they pipe. y 2. A method of positioning material about a pipe in a well under pressure which consists of the steps of trapping the material about the pipe between a plug inside the pipe and a packer on the outside of the pipe, moving the plug through the pipe by fluid pressure and telescoping the pipe to set the packer simultaneously whereby the trapped material is placed under compression and forced into the formation under pressure 3. A method of positioning cement about a pipe in wells including the steps of pumping the cement` through and around the pipe, setting a packer on the outside of the pipe to trap the cement about the lower end thereof by telescoping the pipe, and simultaneously moving the -cem-ent plug downwardly with `the pipe to apply pressure tothe trapped cement. 4. A method of positioning cement about a pipe in wells which consists in pumping the cement through the pipe, and out around the pipe, trapping a body of the cement about the pipe between a packer on the pipe and the cement plug in the pipe and forcing the cement into the formation upon setting of the packer. I

5. A method of positioning cement about a pip in wells which consists in pumping the cement through the pipe and out around the pipe, trapping a body of the cement about the pipe be- 'tween a packer on the pipe and the cement plug in the pipe and forcing the cement into the formation upon setting of the packer, trapping a second body of cement with a second packer above the rst packer, andl setting the second packer to force the second body of cement into the formation.

6. In combination with awell pipe and screen,

LESLIE A. LAYNE.

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