Patent GB-798129-A (GB)
Title: Well apparatus
IPC: E21B43/12
Filed: 1956-01-02
Abstract: 798,129. Wells. U.S. INDUSTRIES, Inc. Jan. 2, 1956 [Jan. 26, 1955], No. 67/56. Class 85 [Also in Group XXVI] A valve for use in wells is opened and closed by means exposed on one side to the pressure of the fluid outside the valve and on the opposite side to the pressure of a gas in a chamber, a passage controlled by a further valve being provided between the exterior of the valve and the chamber. The valve 20 (Figs. 3, 4) has inlet and outlet ports 31, 32, and a valve member 34 controlled by the means 21 which are exposed on the one side to the pressure of the fluid passing through the port 31 and on the opposite side to the pressure of gas (air) in the chamber 36. The passage connecting the chamber with the exterior of the valve comprises inlet port 31, an annulus between housings 30, 37, and the bore of the housing 37, the further valves 30a, 42, 43 being interposed in the passage. Tubing 12 is positioned in the well with sleeve valves 26, 45 closed, and a packer 14 is fitted. A wire is fixed to the valve 30a and the valve 20 is lowered within the tubing to seat within the sleeve 25 of valve 26. The valve 20 is latched to sleeve 25 by slips 28, 29, and moves valve 26 to open port 23 so that fluid from the formation 11 flows into the inlet port 31. The fluid flowing into the valve increases the pressure of air in the passage. With the valve 30a held open by the wire the pressure in the chamber is less than the fluid pressure by an amount determined by the strength of the spring on the valve 42. The valve 20 therefore maintains the fluid in the formation under a constant back pressure. A large increase in formation fluid pressure closes valve 30a so that pressure in the chamber is not altered, and the subsequent decrease in formation fluid pressure opens the valve 30a so that the valve 20 again operates to control back pressure. If the pressure in the chamber gives too high a back pressure to operate the well, the valves 45, 16 are opened so that the pressure in the tubing is decreased and the valve 43 opens to decrease pressure in the chamber. When the desired chamber pressure is reached the valve 45 is closed, and the flow up the tubing is controlled by the valve 20. If the back pressure is too low for well operation the valve 16 is closed until fluid pressure opens the valve 42 to increase the chamber pressure. In modifications either the valve 30a or the valves 42, 43 are dispensed with. In the well shown in Fig. 2 the tubing 12 is open at the bottom, a stop 50 having a control bore 52 is held in the tubing by slips 51, and a valve 53 according to the invention, fixed to a stop 55 and seal 59 having a central bore 57, is supported by the stop 50, and has inlets 63, a spring 54 being inserted between the stop 50 and the valve to ensure that the slips 56 of the stop 55 engage the tube. The valve 53 (Figs. 5A, ... 5E, not shown) has a reservoir which may be charged at the surface so that the initial pressure in the chamber is above atmospheric. When the valve is in the well the pressure in the chamber is lowered by opening valve 18, and is increased by closing valves 16, 18. In a modification of the valve 53 (Figs. 6A, 6B, not shown) the valve opening and closing means are exposed to the pressure of the fluid in the tubing above the valve so that fluid is delivered to the surface at a predetermined pressure. In Figs. 7A, 7B the valve is shown offset from tubing 155, and has inlet ports 150 and an outlet 154 leading to the interior of the tubing. The valve opening and closing means include a piston 165 acted upon by the fluid entering the valve through ports 150, and bellows 163 and head 162 acted upon by air in the chamber 164. The operating characteristics of the valve are altered by lowering a tool 180a to shift a sleeve 180 to the position shown to connect the chamber with the fluid outside the tubing, and by raising the sleeve when the desired chamber pressure is reached. Fuid from outside the tubing also flows through ports 192 during the period in which the sleeve is in the position shown. Other kinds of valve actuated by a tool may replace the sleeve 180. In the valve shown in Fig. 11A a resilient sleeve 237 is pressed on the outside by the fluid exterior of the tubing, and on the in side by the air from the chamber 235. Variations in these pressures causes the sleeve 237 to open or close inlet ports 228. When the inlet ports are open a further resilient sleeve 245 acts as a non-return valve so that fluid will not flow from the tube through ports 247 and discharge through ports 228. A sleeve 249 may be raised to close ports 247. In a modified valve (Figs. 12A, 12B, not shown) ports in a sleeve are brought into register with ports in the tubing, the ends of the sleeve being respectively subjected to the pressure of the fluid external of the tubing and the pressure of the air in the chamber. Two of these valves may be arranged one above and one below a common chamber which may be connected to the exterior or interior of the tubing. Valves according to the invention and having sleeves operable by wire from the surface to alter the pressure in the chamber may be installed in tubing to act as gas lifting valves. U.S.A. Specifications 2,790,395 and 2,804,830 are referred to.