Sammensetning omfattende en holdekile og et setteverktøy for frigjøring av holdekilen, og fremgangsmåte for låsing og selektiv frigjøring av holdekilen

A downhole tool includes a lock for maintaining a slip in a reduced diameter position when running the tool in the well, and selectively releases the slip to move radially outward to a set position to suspend an anchored portion of the tool within a downhole tubular. The tool includes a mandrel having a through passage, with a hydraulic port within the mandrel that is closed to mandrel internal pressure as the tool is run in the wellbore. A ball seat covers hydraulic ports in the mandrel. A ball may be dropped to seat and increase pressure to open the ports. A piston moves in response to mandrel internal pressure applied through the hydraulic port to unlock the locking device, such that further movement of the piston releases the slip from the reduced diameter position to the set position.