自升式钻井平台重复就位滑移分析及控制

Slide analysis and control of jack-up rig during repeat placement

摘要:

自升式钻井平台在东海的作业量随着西湖地区勘探开发的不断发展而在增加。因受台风影响及在同一地点多次作业的原因，自升式钻井平台不可避免地会在上一次作业位置附近重复作业，引起桩靴滑移现象，可能造成就位后悬臂梁覆盖能力下降，无法满足钻井作业需求，甚至影响平台结构安全，造成工程事故，大大增加了作业风险。本文以H9自升式钻井平台桩靴为例，分析了桩靴部分重合工况下的受力特点，研究了海底土体破坏形式，提出了不同类型土质条件下的桩靴水平力计算模型，并利用滑移线有限差分法近似计算桩靴极限载荷。对H9平台在现场重复就位时采取的措施进行了分析，并根据海上作业要求提出了一系列安全控制措施，为安全高效地实现平台重复就位提供了参考。

关键词:自升式钻井平台;重复就位;桩靴滑移;极限承载力;控制措施

Abstract:

With the continuous development of exploration and development in the Xihu area， the number of jack-up drilling platforms in the East China Sea is also increasing. Due to the influence of typhoon and multiple operations in the same location， the jack-up drilling platform will inevitably repeat the operation near their previous position， and cause the pile shoe slide phenomenon； thus leading to the decrease of cantilever operation range when in place， and failure to meet the needs of drilling operation. In the worse case， it may even affect the structural safety of the platform， resulting in engineering accidents with high operation risk. Taking the pile shoe of H9 jack-up drilling platform as an example， this paper analyzes the mechanical characteristics of the pile shoe under partial coincidence conditions， studies the failure mode of seabed soil， and puts forward horizontal force calculation models of the pile shoe in different types of soil. The finite differential method of the slide line is used to calculate the ultimate bearing capacity of the pile shoe. This paper analyzes the measures taken during H9 platform repeat placement， with a series of safety control measures put forward according to the requirements of offshore operation， which can provide a reference for safe and efficient jack-up rig repeat placement.

Key words:jack-up rig;repeat placement;sliding of pile shoe;ultimate bearing capacity;control measures