Comparing the Results of a Simplified Numerical Model With DNV Guidelines for Installation of Subsea Platforms

Installation engineering of subsea platforms has always been one of the major areas of concerns in subsea engineering. These days, conventional installation method, on which subsea modules are lowered directly toward seabed through a lifting wire, is being used widely by offshore operators. Accurate prediction of hydrodynamic forces on subsea structures, particularly when they are passing through water surface zone, is a challenging task in installation engineering of subsea platforms. DNV Rules for Marine Operations are used around the world for prediction of hydrodynamic loads during subsea lifting, checking structural strength and verifying the capacity of the lifting equipments. This paper presents a simplified numerical model for more accurate estimating of characteristic hydrodynamic forces on subsea platforms. Series of different conventional installation analyses are performed in this study to compare the results of the numerical models with DNV guidelines. The main purpose of this study is to figure out the sensitivity of the numerical and DNV results to main input parameters in installation of subsea platforms.