| 摘要 |
A method for disconnecting tubular members and a ball-drop release device including an upper housing connected to tubing and a lower housing connected to a bottom hole assembly. The upper housing includes a recess end having grooves, and the lower housing includes an extension end having splines that fit into the upper housing grooves. The splined connection is designed to resist drilling motor backup torque and prevent the release mechanism from locking up. In the pre-release position, a ball sleeve is disposed within the extension and held in place by shear screws. To actuate the device, a ball, preferably having a density equal to the density of the drilling fluid, is dropped into the well and pumped to engage the ball sleeve. The ball seats with the ball sleeve whether the well bore is disposed vertically, laterally, or sloped upwardly. Once the ball seats, pressure builds behind the sleeve until the shear screws shear. The ball sleeve moves into a recess in the lower housing thereby making the upper and lower housings separable. Before disconnecting the upper and lower housings, fluid flows into the well through recirculation ports on the lower end of the ball sleeve. After separating the upper and lower housings, a fishing tool can grapple the extension to retrieve the lower housing and bottom hole assembly when necessary. When the fishing tool is attached, flow can be resumed into the well through the ball sleeve recirculation ports to aid in retrieval. |
