| 摘要 |
<p>A recloseable circulation valve especially for use in oil wells and the like, includes a cylindrical housing (26) having a central flow passage (28) disposed therethrough and having a power port (30) and a circulation port (32) disposed through a wall thereof. An operating mandrel (34) is telescopically received in the upper end (40) of the housing. A valve sleeve (48) is slidably received in the housing and movable to open and close the circulation port. A power mandrel (50) is disposed in the housing and is connected to the valve sleeve for moving the valve sleeve from an initial position toward an open position. A mandrel lock (72) is provided for locking the operating mandrel and power mandrel together after the power mandrel moves the valve sleeve from its initial position. The power mandrel and valve sleeve are initially held in their initial positions by a shear pin (64) assembly. After the power mandrel moves the valve sleeve upward toward its open position, and the power mandrel is locked to the operating mandrel by the mandrel lock, the circulation valve may be subsequently repeatedly opened and closed by picking up weight from, or setting down weight, on the circulation valve. Methods of testing and treating subsurface formations utilizing such a circulation valve are also described.</p> |
