| 摘要 |
Casing valves for selective well stimulation and control. A well system includes at least one valve interconnected in a casing string operable via at least one line external to the casing string to selectively control fluid flow between an exterior and interior of the casing string, and the casing string, valve and line being cemented in a wellbore. A valve for use in a tubular string in a subterranean well, the valve including: a sleeve having first and second opposite ends, the sleeve being displaceable between open and closed positions to thereby selectively permit and prevent flow through a sidewall of a housing assembly; and first and second pistons at the respective first and second ends of the sleeve, pressure differentials applied to the first and second pistons being operative to displace the sleeve between its open and closed positions. 34 22 24 26 28 30 40 36 40 4 40 30 20 |
