GB622404A - Cementing casings and the like in wells - Google Patents

Abstract

622,404. Cementing casings &c. in wells. BAKER OIL TOOLS, Inc. March 19, 1947, No. 7594. Convention date, April 4, 1946. [Class 85] Apparatus for cementing casings or other conduits in well bores includes a ported tubular member forming a part of a casing string, a valve within the member controlling flow of fluid through the ports thereof, and means in the member for relieving fluid in the casing string below the valve on downward movement of the latter. In Figs. 1 and 6, a collar 10, threaded in the casing string, has ports 13 and is surrounded by a rubber &c. sleeve 14 fixed at its upper end and protected by a spaced, rigid outer sleeve 15, the lower end of the latter extending over radially-inclined nozzles 16. The ports 13 are initially closed by an internal sleeve valve 18 held by shear screws 23 and provided with packers 19, 20; a further shear screw 31, with a head 30, extends loosely through a shouldered bleeder port 28 in the collar 10. A first charge of cement may be forced down through the lower end of the casing string by a plug 27 sufficiently flexible to pass through the valve 18. A ball &e. 24 is then lowered to close the valve 18, a further charge of cement is filled into the casing string, and pressure is applied to shear the screws 23, 31, and lower the valve 18, the cement then passing through ports 13 to displace the rubber &c. sleeve 14 and then flowing through chamber 17 and nozzles 16; simultaneously, pressure below the valve 18 is relieved through bleeder port 28 and passage 33, the screw-head 30 remaining in position to form a non-return valve. In Fig. 8, a hollow shear screw 23a initially assists in holding the valve 18 and after shearing provides for relief of fluid below the valve, while in Fig. 9, a spring-pressed ball valve 36 closes the relief port 35 until the valve 18 moves.