Coupled Motion Analysis Of Semi-submersible Living Platform And Production Platform During Berthing

The semi-submersible living platform is connected to the production platform through a telescopic gangway,maintaining the continuous operation of the production platform at sea,which significantly improves the production efficiency.During the berthing of the two platforms,due to the combined effect of wind,wave and current,it is easy to cause large movements of the platform and induce major safety accidents.Therefore,focus on the berthing process of the two platforms,researching the hydrodynamic loads and the coupled motion response of two platforms have important engineering significance for ensuring the safety of the platform berthing process and achieving smooth transfer of goods and personnel.This paper designs a new type of side-by-side mode for the berthing of semi-submersible living platform and production platform.Based on the three-dimensional potential flow theory,the coupled multi-body's wave load and motion response in frequency domain is calculated to analyze the influence which is caused by different spacing,different wave directions and hydrodynamic interaction.The method of setting different parameters in Kalman filter gain and controlling gain is studied before analyzing the dynamic positioning motion response in time domain.The coupled motion analysis model of two semi-submersible platforms are established in time domain.The dynamic positioning control parameters of two platforms are optimized and tuned through a large number of numerical simulations,and two groups of dynamic positioning control parameters which are most likely to improve the sea condition for berthing operation are got.Considering eight kinds of sea conditions and 24 kinds of wave angles to calculate the environmental loads and the coupled motion response of two platforms.Considering the dynamic positioning capability of the berthing system and the allowed relative displacement of two platforms,the sea conditions for safe berthing operation are determined.Based on a large number of analysis and research work,the frequency domain hydrodynamic response characteristics of two semi-submersible platforms in large spacing side by side berthing mode are obtained.The tuning method for DP control parameters of multi-body in the time domain calculation is proposed.Based on the experience,the upper limit conditions of two platforms' relative displacement are designed,and the safe sea conditions for berthing operation are determined.The work of this paper has guiding significance for the application development of semi-submersible living platforms and the innovation of development mode of oil and gas fields.