| 摘要 |
A cementing port collar has an opening sleeve biased from a closed position to an opened position relative to the collar's exit port, and a first restraint temporarily holds the opening sleeve closed. The collar also has a closing sleeve biased from an opened position to a closed position, and a second restraint temporarily holds the closing sleeve opened. During cementing, the first restraint is electronically activated with a first trigger to release the opening sleeve opened so cement slurry can pass out of the collar's exit port to the borehole annulus. When cementing is completed, the second restraint is electronically activated with a second trigger to release the closing sleeve closed to close off the collar to the borehole so the cement can set. The restraints can include bands of synthetic fiber, which are burned by fuses activated by a controller of the collar responding to passage of RFID tags. |
