Midline Tie-in

Midline Tie-in or Above Water Tie-in (AWTI) is an operation where two laid down pipelines on the seabed are welded together after being lifted above water using vessel davits. 

For AWTI we determine/provide:

• Steps for recovering the pipelines
• Welded Configuration for recovered pipes
• Steps for lowering the completed pipeline
• Weld excavation analysis
• Minimum weld thickness assessment for removal of the welding clamp
• Offshore Procedures to be followed during execution

Static Code checks (pipeline integrity) are performed for every static loadcase. Dynamic Analysis is performed for the respective worst case in Pipe Recovery, Welded configuration and Laydown. DNV buckle checks are used to ascertain pipe integrity during dynamics.

Software Employed: Orcaflex

source : http://www.oesl.nl/expertise/pipelay