DOWNHOLE SURGE PRESSURE REDUCTION SYSTEM AND METHOD OF USE

摘要

A system for reducing pressure while running a casing liner (20), hanging a casing liner (20) from a casing (C2) and cementing the liner in a borehole (BH) during a single trip downhole is disclosed. Some of the components of the system are: 1) a bypass or diverter sub (12) for reducing surge pressure having either an incremental breakaway seat or a yieldable seat (140), 2) a container or manifold (10) for launching a smaller ball (52) used to close the bypass (12), a larger ball (66) used to hang the liner (20) in the casing (C2), and a drill pipe wiper dart (42) for cementing, and 3) a guide shoe (14) with multiple openings and no float valve to provide proper flow of drilling fluid up the liner (20) and out the port of the bypass (12) to reduce surge pressure and to provide for proper cementation. Advantageously, methods for operation of this surge pressure reduction system and its components are also disclosed.