基于海试的水下采油树力学特征影响因素敏感性分析

Sensitivity Analysis of Factors Influencing Mechanical Characteristics of Underwater Christmas Trees Based on Tests

为了探究吊装、入水、深水下放及海底坐落4种典型工况下采油树下放系统力学特性及影响因素的敏感性,基于自主改进的水下采油树下放系统力学模型,结合有限元数值模拟,开展典型工况下采油树下放过程的参数敏感性分析,以此确定各阶段采油树下放系统的力学行为特征。分析结果表明,不同工况、不同影响因素下采油树下放系统力学特性存在较大差异;吊装阶段主要受风载荷的影响,而入水、下放及坐落阶段主要受波浪载荷影响;风载荷主要作用于采油树下放的前40 m,对于深水下放及海底坐落阶段几乎无影响;入水角度与入水砰击力呈正相关,且采油树的极限入水角度为17.6°;平台共振对采油树横向位移量存在一定影响,但对采油树弯矩变化无影响。

In order to discuss the mechanical characteristics of subsea Christmas tree lowering system and the sensitivity of their influencing factors,based on the self-improved mechanical model of subsea Christmas tree lowering system,the parameter sensitivity under four typical working conditions(hoisting,getting-into-water,deep water lowering and seating seabed)in subsea Christmas tree lowering process was analyzed using finite element numerical simulation.The analysis results show that there is a great difference in the influence factors of the mechanical characteristics of the subsea Christmas tree lowering system under different working conditions.In hoisting stage,wind load is main influencing factor.In getting-into-water,deep water lowering and seating seabed stages,wave load is main affecting factor,while the wind load acts mainly in the first 40 m of the lowering process,and it has little effect in deep-water lowering and seating seabed stages.There is a positive correlation between getting-into-water angle and water slamming force,and the limit getting-into-water angle of subsea Christmas tree is 17.6°.Platform resonance has certain influence on lateral displacement of subsea Christmas tree,but it has no influence on bending moment of subsea Christmas tree.