US2079830A - Apparatus for blanking and cementing off perforated well casings in a well bore - Google Patents

Description

May 11, k1937.

R. C. BAKER El' AL APPARATUS FOR BLANKING AND CEMENTING OF PERFORATED WELL CASINGS IN A WELL BORE ld IN1/EN 0R.

ATTORNEY Filed Nov. 23, 1,955

Patented May 11, 1937 PATENT OFFICE APPARATUS FOR BLANKING CEMENT-- ING OFF PERFORATED WELL CASINGS UNITED STATES IN A WELL BORE tion of California Application November 23, 1935, Serial No. 51,283

8 Claims.

This invention relates to apparatus for blankiig-olf sections of perforated casing in an oil well In some oil elds it is the practice of lining that portion of a well bore extending ,through a producing zone with perforated or screen casing. For various reasons it becomes sometimes 'desirable to blank-olf all or a portion of such perforated casing and to ll the space between the blanked-oif portion of such casing and the well bore with cement to prevent the migration of fluids vertically between the casing and the wall of the hole; and likewise to prevent the entrance of fluid into the casing through the perforations.

It is the principal object of the present invention to provide a simpleandoveryeiiicient apparatus for use in blanking-oif a desired section of perforated well casing while the same is in a well bore, which device being also capable of use in washing out the space exteriorly of the blankedorf casing section, and then lling the same with cement.

One form which the invention may assume Vis exemplified in the following description and illustrated by way of example in the accompanying drawing, in which:

Fig. 1 is a view in central vertical section through a portion of a well bore in which perforated casing is placed, and showingmy improved apparatus positioned therein for operation.

Fig. 2 is a view similar to Fig. 1, showing the apparatus in the position which its parts assume during operation.

Referring more particularly to the accompanying drawing, I0 indicates a well bore and II indicatesa section of perforated casing therein, which' in some ilelds is used to line the bore\where it extends into or through the producing ne. It is s'ometimes desirable to blank-off either a por- `tion or all of the producing zone, which can be accomplished by the use of my apparatus, indicated at I2. i

This apparatus comprises an elongated hollow body including a central tube I4 which is fitted at its upper end with a coupling I5. 'I'he upper end of this coupling is formed with a female lefthand thread so that ,fit/may be connected to the lower end of a. running-in tubing I6. 'I'he reason for the left-hand thread is so that the runningin tubing I6 may, under some conditions, be disconnected from the coupling I5, when it is desired to leave the apparatus I2 in place in the casing but remove the running-in tubing I8.

The central Atube I4 is fitted adjacent its upper f rial. The lower end of this packing sleeve I9 is securely fastened to the lower end of the lower head member I8. In both instances the ends of the sleeve I9 are secured to the heads II and I8 by collars 2li threaded to the heads II and I8, forming a water-tight connection therebetween.

It will be noticed that the exterior diameters of the collars 2li are just slightly less than the interior diameter of the perforated casing II, and it will be likewise noticed thatwhen the sleeve I9 is in its normal or collapsed condition, that it is likewise less in external diameter than the internal diameter of the casing I I.

The central tube or fluid conducting member I4 is provided with two radial ports 2| at a point intermediate the upper head I1 and the lower head I8. These ports are controlled by saxophone type spring-pressed check valves 22, which are arranged on the exterior of the tubing so that pressure from within the tubing will open them.

butwhen the pressure within the packing sleeve I9 exteriorly of the tube I4 is greater than the pressure within the tube I4, the valves will be maintained seated.

The valve members 22 have projecting lugs 23 which projectf` inward-ly through 'the ports -2I to"1V a point within the central tube I4.v The provision of these lugs enables a spear or other tool, such as indicated in dot and dash lines at 24 in Fig. 2, to be lowered down through the central tube I4 to open the valves 22 and enable the packing sleeve I9 to be collapsed byv relieving the pressure therein. I

The lower head I8, as previously stated, is hollow and cylindrical and is fitted within'its upper end with a bridging valve seat member 25 which is connected with thehead member I8 by a shear pin 28. The lower end of the head member I8 is formed with a. central back pressure valve port 21 with which a back pressure poppet type valve 28 cooperates. This valve 28 is provided with a stem 29 guided within the head I8 for vertical reciprocation. An expansion spring 30 is provided which engages a spider 3| in the head I8 at its lower end and a collar 32 at the upper end oi' the valve stem 29 to constantly tend to maintain the valve 28 seated to prevent the passage of Huid upwardly through the lower head I8. The valve seat member 25 is connected by legs 33 to the collar 32 by means of a shear pin 34.

When the valve seat member 25 is held in place, as illustrated in Fig. 1, it, by its connection with the valve stem 29 through the collar 32, holds the valve member 28 unseated so that fluid may pass upwardly through the head member i8 and upwardly through the central tube It. This is desirable because it is necessary when lowering the apparatus I2 into the casing to permit uid already in the bore to pass freely upwardly through the apparatus and through the tubing I6.

To cooperate with the valve seat member 25 ls a bridging ball valve member 55 which is not placed in position in the device' until after the apparatus is lowered to the point of operation. The ball valve 35 may be dropped down through the running-in tubing I6 so that it may seat on the valve seat member 25 and shut off the passage of uid downwardly through the tubing Id.

In operation of the device, assuming that it is constructed and assembled as illustrated in Fig. l, it is lowered into the hole, and, as it' is lowered down the bore, fluid in the bore may pass upwardly through the apparatus, through the central tube I and upwardly through the running-in tubing I6 as it is lowered. The apparatus is lowered to a point Where the packing sleeve i9 will register with that section of the perforated casing I I which it is desired to blank-olf. When this point is reached, the ball 35 is dropped into the tubing I6 and caused to lower until it seats on the upper end of the valve seat member 25. Pressure is then built up in the central tube I d by the pumps connected with the top of the running-in tubing I6.

The pressure which is required to open the valves 22 is less than the pressure required to shear the pin 26 which holds the valve seat member 25 in place. Therefore, the ball valve 35 in cooperating with the seat member 25 eieotively shutsoi the lower end of the central tube Hl. Fluid under pressure is consequently forced outwardly through the valve ports 2| in the central tube I4, and pressure is built up inthe chamber between the packing sleeve I9 and the central tube I 4 until this sleeve expands into tight engagement with the inner periphery of the perforated casing II, eiectively sealing the perforations therein. The pressure required to eiect this seal is less than required to shear the pin 26. However, immediately that a sealing action is effected between the packing sleeve I9 and the perforated casing II, the pressure is built up to a point where it shears the pin 26, thus rendering the bridging valve mechanism at the lower end of the central tube Id ineffective, because the valve seat member 25 is lowered to a point where the ball valve 35 is no longer effective. This is illustrated in Fig. 2. At the same time, the shear pin 34, which connects the valve seat member 25 to the collar 32 on the upper end of the valve stem 29, is sheared releasing the valve member 28 and permitting the same to close.

the tubingI I6 is suiiicient to open the valve 28 to maintain circulation. However, when the pressure within the tubing I6 drops, the pressure in the bore, in conjunction with the spring 30, seats the valve 28, preventing theA passage of fluid upwardly through the lower head I8.

However, the fluid pressure pumped downwardly through aoraeeo If it is merely desired to blank-oli the casing, the tubing I 6 may then be revolved in a left-hand direction, disconnecting it from the coupling I5, thus permitting the tubing I 6 to be removed from the bore. inasmuch as the valves 22 will be closed, the pressure interiorly of the packing sleeve I9 will be sumclent to maintain the seal.

However, it may be desired to cement olf that section of the perforated casing with which the apparatus is aligned. In such an instance the tubing I6 is not disconnected `from the coupling I5 until the cementing operation is complete. In such an instance washing fluid is first pumped downwardly through the tubing I6, downwardly through the central tube I4 and the head member I8 and out of the valve port 2l in the lower end of the head member I8. This fluid will pass out of perforations below the head member I8, and then upwardly between the exterior of the perforated casing II and the wall of the hole, gaining entrance back into the casing through perforations therein above the apparatus I2, thus washing the mud out of this space and preparing this space for cementing. Cement slurry under pressure is then forced downwardly through the tubing I 5 downwardly through the apparatus, and it will follow the same path as the washing iluid. Sufcient cement is pumped downwardly in this'manner until the area between the blanked-oil section and the wall of the vhole is lled with cement. The tubing I6 is then disconnected from the coupling I5, as described, and washed out and removed from the bore.

lf it is desired, however, to remove the apparatus after the cementing operation, a tool such as indicated at 2d in Fig. 2 may be lowered down through the tubing to open the valves 22, collapsing the packing sleeve I9; then the entire apparatus may be removed upwardly from the casing. The removal, however, will unatfect the cement, due to the fact that it will already have set and will act to blank-olf the perforated casing II l 'When the apparatus is used to wash out and cement casing, a bridge may be formed in any preferred manner in the perforated casing II below the point where the lower head I3 of the apparatus will be positioned. Likewise, a circulating jar of any preferred design may be incorporated in the running-in tubing I6 to enable the latter to be Washed out immediately following cementing.

From the foregoing it is obvious that we have provided a, comparatively simple apparatus which may be used in blanking-oi perforated casing while the same is in a well bore, and which also may be used in washing out the space between such blanked off area and the well bore and illling such space with cement.

While we have shown the preferred form of our invention, it is to be understood that various changes may be made in its construction by those skilled in the art without departingr from the spirit of the invention as defined in the appended claims.

Having thus described our invention, what we Nclaim and desire to secure by Letters Patent is:

l. An apparatus of the character described comprising an elongated hollow body adapted to be connected at its upper end to a string of running in tubing, an expansible packing sleeve ooncentrically arranged about said body and connected in ahum-tight manner at its ends to said body, check valve means in said body at a point intermediate the ends of said sleeve to enable fluid to be forced from said body between said body and said sleeve, means in said body below said check valve means preventing the `passage of iluid downwardly through said body, said latter-named means being capable of being rendered ineffective by fluid pressure within the body above that required to open said check valve means.

`2. An apparatus of the character described comprising an elongated hollow body adapted to be detachably connected at its upper end to a string of running in tubing, an elongated expansible packing sleeve of a diameter greater than the diameter of the central portion of said body, said sleeve being arranged concentrically on said body, a duid-tight connection between the ends of said sleeve and said body, said body having valve ports formed therein at a point be-` tween the ends o'f the sleeve whereby fluid from within the body may pass into the space between the sleeve and the exterior of the body to expand the sleeve, check valves normally preventing the return of iluid from between the sleeve and the body into said body, bridging valve means in the bodyfbelow said ports to interrupt the ow of iiuidA through the body, said bridging valve means capable of being rendered ineffective by duid pressure within the body,`the pressure required to render said bridging valve means ineiective being greater than required to open said check valves and expand said sleeve.

3. An apparatus of the character described comprising `an elongated hollow body adapted to be detachably connected at its upper end to a string of running in tubing, an elongated expansible packing sleeve of a diameter greater than the diameter of the central portion of said body, said sleeve being arranged concentrically on said body, a uid-tight connection between the ends of said sleeve and said body, said body having valve ports formed therein at a point between the ends of the sleeve whereby iluid from within the body may pass into the space between the sleeve and the exterior of the body to expand the sleeve, check valves normally preventing the return of iluid from between the sleeve and the body into said body, the lower end of said body being formed with a valve port, a back pressure valve normally controlling said port, bridging valve means in said body between said back pressure valve and said check valves normally preventing the passage of fluid downwardly through the body, said bridging valve means capable of being rendered ineective by uid pressure within the body above the same, the fluid pressure to render the said bridging valve means ineffective being considerably greater than that required to open said check valves and expand said sleeve.

4. An apparatus of the character described comprising an elongated hollow body adapted to be detachably connected at its upper end to a string of running in tubing, an elongated ex- -pansible packing sleeve of a diameter greater than the diameter of the central portion of said body, said sleeve being arranged concentricallyl `on said body, a fluid-tight connection between the ends of said sleeve and said body, said body having valve ports formed therein at a point between the ends of the sleeve whereby fluid'from within the body may pass into the space between the sleeve and the exterior of the body to expand the sleeve, check valves normally, preventing the return of fluid"from between the sleeve and the valve means in said body between said back pres# sure valve and said check valves normally preventing the passage of fluid downwardly through the body, said bridging valve means capable of being lrendered ineiective by fluid pressure within the body above the same, the iiuid pressure to render the said bridging valve means ineffective being considerably greater than that required to open said check valves and expand said sleeve, a connection between said bridging Valve means and said back pressure valve holding said back pressure valve open, said connection being disrupted when said bridging valve means is rendered ineffective.

5. An apparatus of the character described comprising an elongated hollow body adapted to be connected at its upper end to a string of running in tubing, an expansible packing sleeve concentrically arranged about said body and connected in a duid-tight manner at its ends to said body, check valve means in said body at a point intermediate the ends of said sleeve to enable fluid to be forced from said body between said body and said sleeve, means in said body below said check valve means preventing the passage of fluid downwardly through the lower end of the body until the iluid pressure in the body exceeds that necessary to open said check valve means and expand said sleeve.

6. An apparatus of the character described comprising,` a center tube adapted to be connected to the lower end of a string of running in tubing, an upper and a lower head member connected with said tube, back pressure valve means in the lower head member to permit fluid to be pumped downwardly through 'said tube and head member but not in the opposite direction, an expansible sleeve arranged concentrically about said center tube and connected at its ends in a fluid-tight manner to said head members, said center tube having ports formed therein between said head members to enable uid to be pumped in the space between said tube andsaid sleeve to expand the latter, check valve means controlling said ports to prevent the back flow of uid into the body, and bridging valve means between said back pressure valve and said valve ports vto prevent the ow of fluid downwardly through said tube until the fluid pressure in the tube reaches a point exceeding that required to open said check valve means and expand said sleeve.

7. An apparatus of the character described comprising a center tube adapted to be connected to the lower end of a string of running in tubing, an upper and a lower head member connected with said tube, back pressure valve means in the lwer head member to permit iiuid to be pumped downwardly through said tube and head member but not in the opposite direction, an expansible sleeve arranged concentrically about said center tube and connected at its ends in a fluid-tight manner to said head members, said center tube having ports formed therein between said head members to enable uid to be pumped in the space between said tube and said sleeve to expand the latter, check valve means controlling said ports to prevent the back flow of uid into the body, and means for opening said check valve means from within said body.

8. An apparatus of the character described comprising a center tube adapted to be connected to theilower end of a string of running intubing, an upper and a lower head member connected with said tube, back pressure valve means in the lower head member to permit fluid to be pumped 1o ports to prevent the beek ow of uicl into the aoeaeee body, bridging valve means between said back pressure valve and said valve ports to prevent the ow of fluid downwardly through said tube until the uid pressure in the tube reaches a predetermined point above that required to pen said check valve means and expand said sleeve, and means for opening said check valve means from within said body to relieve said pressure.

REUBEN C. BAKER. CLARENCE E. BURT.

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