Study of the Influence of Initial Conditions on Jacket Structure Launching Operation

Abstract

Launching is one of the most hazardous stage in the jacket structure installation. The jacket is launched into the sea by a barge. This study aims to determine the effect of initial launching conditions and analyze the jacket structure during the launching process. The initial conditions of barge trim and draft will be varied to determine the effect of these parameters on barge stability, separation time, rocker arm reaction, jacket bottom clearance, maximum barge trim and jacket strength. Overall 24 variations of initial barge trim and draft have been investigated. The results show that the minimum barge stability range is 49.02o, the minimum area ratio (K) is 12.16 and the minimum metacentric (GM) is 22.90 m. These values meet the limiting criteria of barge stability for launching process. Further, the effect of barge trim is found to be more significant than the draft on the separation time, rocker arm reaction, and maximum barge trim. The effect of barge trim and draft is not significant on the bottom clearance jacket. On jacket strength, there are 14 combinations of barge trim and draft where the structure is safe to be launched as shown by the UC value of less than 1.0.