Development of a Re-closable Snubbing Service Tool

In order to avoid the reservoir damage and environmental pollution caused by the well killing operations, a new type of re-closable snubbing service tool was designed based on the structural principle of track reciprocating displacement and spring-energized reset mechanism, which developed to replace the large and complex snubbing unit. Through structural mechanics analysis, the multi-phase small-angle reversing guide rail has the characteristics of short switching travel and small frictional resistance, which could overcome the travel limitation of spring reset. Through in-house testing, the guide rail failed to switch positions result from spring torque, an embedded bearing was designed to eliminate the spring torque and enable the guide rail to switch positions smoothly. Through field test verification, this new snubbing service tool was able to withstand pressure of 35 MPa and temperature of 90 ℃, as well as able to be repeatedly switched and used, with the advantages of easy operating, safety, environmental protection and economic. The operation period was shortened by 50% compared with the conventional anti-spill and liquid production operation, which have a significant economic benefits.