Spanner Joint System
Tradition has dictated that all landing string operations conducted on a well using a semi-submersible or a dynamically positioned drilling vessel must make use of a subsea test tree/subsea intervention system. This is true when dealing with an underbalanced or ‘live’ well.
However, an ever increasing number of operations, particularly in the U.S. Gulf of Mexico, work in an overbalanced condition. This, in combination with low to moderate heave and predictable weather conditions of 24-hour notice, means that operators can consider a simpler and more cost effective solution such as the Halliburton spanner joint system. This system allows the operator the ability to access the well using the traditional tubing hanger running tool, close and isolate the annulus with the blowout prevention pipe rams, close and circulate the riser using the annulars and also have the fall back position of a shearable sub.
Using this system eliminates the dual barrier protection provided by the safety tree, and any coiled tubing cutting capability. The gain is simplicity and considerable cost savings.
Of course, each completion or workover has its own individual circumstances and safety should not be compromised at any time. Therefore it is essential that before selecting this type of solution, operators should ensure that the necessary barriers are in place for each operation (both planned and unplanned).