| 摘要 |
The present invention relates to downhole tools, and in particular an underreamer tool for use in a wellbore of an oil or gas well and a method of actuation. In an embodiment, the underreamer tool has body having a longitudinal axis and a fluid conduit, a tool element and an actuation device configured to urge the tool element relative to the body from a first configuration into a second configuration. In this embodiment, a portion of the tool has a curved actuation surface and as the tool element is urged across the curved actuation surface, the tool element is moved radially with respect to the body of the tool. Typically, the actuation device may include a piston driven by pressure of fluid circulated through the fluid flow conduit. |
