| 摘要 |
A well tubing valve is described, having a substantially tubular body connected in a tubular string and a rotational valve member having at least one aperture. The valve member, which may be a sleeve having a part spherical surface, is rotationally moveable relative to the body to align and misalign the aperture in the valve member with a port in the body. The valve member is actuable to rotate relative to the body in a single direction, and moves from the open position to a closed position and back by rotation in the same sense. In an alternative embodiment, two such valves members are provided and each valve member is actuable from a common control line to at least three operating positions, to incrementally adjust flow through the ports. Methods of operation are also described. |
