Patent GB-774783-A (GB)
Title: Improvements in flow-control apparatus for two-zone wells
IPC: E21B43/14
Filed: 1955-12-09
Abstract: 774,783. Flow control apparatus for wells. OTIS ENGINEERING CORPORATION. Dec. 9, 1955 [March 7, 1955], No. 35426/55. Class 85. Flow control apparatus for a completed two-zone well comprises sub-surface valve means for controlling the flow from the lower zone through a conduit string and sub-surface valve means for controlling the flow from the upper zone through the annulus between the well casing and the conduit string, means for controlling said valves separately or together from ground level, and safety means for automatically closing said valves in response to a predetermined pressure change in the well. Lower zone flow passes through ports 11, Fig. 2C, into the well casing 10, and into the conduit string 12, the annulus between the string 12 and the casing 10 being packed off by a packer 14 just above the ports 11, then up the string 12 through a base 23, past a valve head 58, through ports 44 in a valve sleeve 41 and up the string 12 to a take off connection 16 in the well head. The sleeve 41 is urged upwards by a spring 52 to close the ports 44 by a shoulder 45 engaging a seat 46. Pressure fluid is supplied by a pipe 50 from the well head, through a port 51 to act on a piston 48 attached to the sleeve 41 to push it downwards to open the ports 44, as in Fig. 2A. Upper zone flow passes through ports 15 into the annulus between the casing 10 and the string 12 above the packer 14 and below a packer 22, then through ports 24, upwards through an annulus 26 between an outer fixed sleeve 29 and an inner movable sleeve 28 and then upwards through the annulus 13 between the well casing 10 and the string 12 to a take off connection 17 in the well head. The movable sleeve 29 has packing rings 63 at its lower end, Fig. 2C, and is urged upwards by a spring 65a, Fig. 2B, engaging beneath a piston 60 attached to the upper end of the sleeve so that the packing rings 63 pass above the ports 24 and close the annulus 26. Pressure fluid' is supplied by the pipe 50 through a port 65 to the upper side of the piston 60 to push the sleeve 28 downwards and open the annulus 26. Separate pipes 50 may be used to control each piston 48, 60 separately. Fig. 1 shows an arrangement where the pipe 50 is connected through a flow bean 212 to a reservoir 211 which is connected through pilot valves 215 and flow beans 215a to the connections 16, 17 whereby the valves 215 react to reduce the pressure in the pipe 50 and shut off the flow from both zones in response to predetermined pressure changes in the connections 16, 17. The valve head 58 may be removed on a wire leaving an open central bore through the string 12 for the passage of work-over tools. In a modification the two valves are formed as an inner part of a tool which can be withdrawn from the rest of the tool and conduit string leaving an open central bore for work-over tools. In another modification the movable members of the two valves are formed on the same tubular member and operated together by one piston. In further embodiments, e.g. Fig. 7, the valve means 198 for the upper zone flow is placed in a tubular member 191 which is parallel and side by side to the conduit string 12 containing the valve means 196 for the lower zone flow. Specifications 774,784 774,785 and U.S.A. Specification 2,673,614 are referred to.