台风下TLP立管系统可靠性评估

针对在南海海域频发的台风自然灾害,考虑海况随机性、结构随机性以及作业参数的随机性,采用梯度投影确定取样点的响应面法,分别建立P2D、D2P和P2P(P指生产立管,D指钻井立管)三种作业模式下TLP串行立管系统的结构极限状态方程。并在建立立管可靠性分析模型的基础上,确定一种立管可靠度计算方法。算例结合南海某TLP平台给出了上述方法的具体应用。研究表明,10年一遇台风情况下,P2D、D2P和P2P三种工况中生产立管系统的失效概率均小于0.001%,钻井立管系统的可靠度分别为0.016%和0.113%。在大于200年一遇的强台风情况下,P2P工况时的上下游生产立管系统失效概率均大于0.32%和0.018%。因此建议10年一遇台风情况下,停止钻井立管作业;在大于200年一遇的强台风情况下,停止生产立管作业。研究结果可为南海TLP立管系统可靠度评估及安全作业技术支持。

Reliability assessment of TLP riser system under typhoon

A reliability analysis methodology for deep water riser system aiming at typhoon disaster is presented. The stochastic of sea, structure and operating parameters is considered, using RSM for the sampling point determined by the gradient projection to establish the structure of limit state equation of three operation conditions: P2P (production riser to production riser), P2D (production riser to drilling riser) and D2P (drilling riser to production riser). After creating a reliability analysis model of riser, a method for calculating riser reliability is determined. A case study is then conducted for the specific application of the proposed method by using a TLP platform in South China Sea. The result shows that the failure probability of production riser system is less than 0.001%, the failure probability of drilling riser system is respectively 0.016% and 0.113% in three operation conditions under 100 year typhoon. Under more than 200 year typhoon, the upstream and downstream production riser systems are respectively more than 0.32% and 0.018% under P2P. Suspension of drilling is recommended under 10 year typhoon. Suspension of production is recommended under more than 200 year typhoon. The result of study can provide technical support for riser system reliability assessment and safety operation of TLP platform in South China Sea.