BALL SEAT HAVING COLLAPSIBLE HELICAL SEAT

摘要

Apparatuses for restricting fluid flow through a well conduit comprise a tubular member having a helically-shaped seat member disposed within the tubular member. The helically-shaped seat member comprises first and second ends, a first position in which the first and second ends relative to each other to provide a first diameter opening through the helically-shaped seat member for receiving a plug element, and a second position in which the second end is disposed axially below and radially outward relative to the first end to provide a second diameter opening through the helically seat member, the second diameter being greater than the first diameter thereby facilitating the plug element passing through the helically-shaped seat.