| Oil consumption in the world grows rapidly, especially in China. Offshore platform, as the infrastructure of offshore oil and gas exploration, plays a very important role. There have been more than 200 offshore platforms built in China since the 1960s, most of which are jacket offshore platforms. Some of them were damaged in extreme environment, as the resistance of these platforms reduces differently in hostile environment, and some of them need to extend their service for exploitation needs, so safety evaluation of them is needed.With large redundancy of jacket platform, it is more reasonable to evaluate the system safety level of these jacket platform structures. The API codes have provided the demands of safety evaluation of the structure system without the safety index of the whole structure system so that it can't be applied in actual projects. In this paper, the system safety level of jacket platform structure is analyzed and calibrated with the specific structure of JZ20-2-3 jacket platform, and main contents are as follows:1A finite element model of JZ20-2-3 jacket platform is established as well as its environmental load and combination load cases are determined.2The ultimate strength of the structure with different combination load cases and different directions of key load is figured out and analyzed so that direction of the weakest platform strength and dominate load combination case are found out. Then, in order to provide basis of the determination of system safety index, the ultimate strength of the structure with different damage is calculated.3The deterministic system safety index and reliability system safety index are calibrated. And the impact of the different design reference periods and environment load return periods on these indexes is analyzed.This research provides some references and suggestions on the safety evaluation of other jacket platform structures and calibrating the system safety level of jacket platforms structure. |
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