Patent attributes
A sidetrack window is cut in a cased wellbore by disposing a sidetracking assembly within the cased wellbore. A first ball is deployed into a drill string of the sidetracking assembly. The first ball leaves the drill string and lands on a ball seat of a cement retainer to block fluid outlet of the cement retainer. Then, the cement retainer is set and a second fluid outlet of the cement retainer is exposed. Cement is flowed through the drill string to the portion of the cased wellbore downstream of the cement retainer to plug the portion of the wellbore. The whipstock assembly is separated from the cement retainer. A second ball is deployed inside the drill string to land on the seat of the whipstock assembly to block a fluid outlet of the whipstock assembly. The whipstock assembly is anchored in the cased wellbore and the milling system is actuated to begin cutting the sidetrack window.
