TBSA is the working seal between formation pressure and the production tubing.
The TBSA is used in single- or multiple-zone installations to provide a surface indication that the seal assembly is correctly positioned in the polished bore Production tubes, tailpipe and other accessories can be added below.
TBSA can be configured for all sizes, run at the end of the tubing and stabbed into the exisitng liner top or lower packer's PBR. The PBR length will be determined based on the amount of themal movement calculated.
Tubing above the TBSA can be crossed over to larger size if required.