Safety check valve for coiled tubing

摘要

A spring-loaded check valve, mounted between a coiled tubing stripper and a BOP stack seals well bore pressure from the atmosphere when the coiled tubing is removed from the well bore. When no coiled tubing is in use, the check valve is shut against well bore pressure. When coiled tubing is inserted through the stripper and before the coiled tubing enters the BOP stack, the coiled tubing butts against the check valve and opens it, permitting insertion of the coiled tubing.