GB688727A - Positive shut-off ported casing apparatus for well cementing - Google Patents

Abstract

688,727. Well packers. BAKER OIL TOOLS, Inc. Dec. 4, 1950, No. 29655/50. Class 85. A valve-controlled ported casing apparatus for cementing a well bore, Fig. 1, comprises a tubular member 10 forming part of a conduit string B, C and having a side port 14, a lower inner sleeve valve member 15 disposed initially across the port to close it, and an outer sleeve valve member 31 on the exterior of the tubular member which is disposed initially to allow fluid passage through the port but which is hydraulically shiftable to the port-closing position by fluid fed under pressure through an opening 37, normally closed by a releasably secured upper inner sleeve valve member 45. In operation, with both sets of ports 14, 37 closed as in Fig. 1, cement slurry is pumped directly into the casing string and passes through the-central bores of the inner valve members 15, 45 to be discharged, e.g. from a casing shoe, into the annulus around the casing string. A weighted plug member 51, Fig. 5, is then dropped into the well casing and passes through the fluid therein to seat itself within the bore 50 of the member 15, so that, when pressure is again applied to the fluid, the screws 19 shear thus allowing the valve member 15, to move downwards and open the port 14. During downward movement of the valve member 15, cement below the valve member is allowed to bleed past the seal ring 20 and the stop 25 to the enlarged diameter groove 23. Washing fluid followed by cement slurry is now discharged through the ports 14. To close the ports upon discharge of the required quantity of cement slurry, a top cementing .plug 58, comprising a metalcapped rubber body 70 attached to a fluted - guide. 75, is placed within the bore of the upper inner sleeve valve member 45. When the fluid above the plug 58 is pressurized, the screws 48 shear and the valve member 45 moves downwards to expose'the upper ends of the elongated ports 37 to the fluid which passes therethrough and into the cylinder space 38. The fluid then shears the screws 36 and moves the outer sleeve valve member 31 down to close the ports 14 as shown in Fig. 5. Should well conditions tend. to prevent the member 31 moving down sufficiently to close the port 14, the fluid force on the plug 58 causes the plug and the inner sleeve valve member 45 to move downwards, the force being transmitted to the outer sleeve valve member via the keys 82. The slurry trapped between the members 15, 45 passes out through passages in the plug 51, the passages being initially closed by a valve head retained by a frangible pin.