| 摘要 |
[0035] In wellbore completions it is desirable to access multiple formation zones in a single well where the more formation zones that can be accessed tend to make the well increasingly economically viable. In an embodiment of the current invention a dart having a tapered or angled spline with a particular width on the darts exterior surface is pumped into a casing string having a number of devices Incorporated at strategic locations along the casing string. Each of the devices incorporated into the casing string have a slot as a part of the device. Each slot also has a particular width. As the dart passes through the devices incorporated in the casing string but towards the surface of the targeted device, the width of the tapered or angled spline is less than the minimum width of the slots in each of those upper devices. Therefore the dart does not engage or otherwise affect any of the upstream devices. However when the dart reaches the targeted device the width of the spline matches the width of the slot such that the slot captures the spline and the dart to which the spline is attached thereby sealing the wellbore at the targeted device. |
