深水无隔水管钻井钻具稳定性计算分析

Analysis and calculation of drill tool stability in deepwater riserless drilling

深水无隔水管钻井技术主要是指钻井作业过程中未安装隔水管,即在开放水域环境下进行钻井作业。无隔水管钻井具有操作简单、节约用时等诸多优点,是深水钻井技术发展的重要方向之一,但无隔水管钻井的钻具易受到深水海浪、海流、平台升沉等多项复杂因素的叠加影响,引起管柱弯曲、疲劳甚至失效,导致井下复杂事故。通过分析深水无隔水管钻井钻具的力学稳定性质,开展钻具受波浪流多重作用、钻具空间形态、钻具动载荷等因素影响的研究分析,为钻具安全稳定性分析提供指导,并结合我国某深海项目采用的无隔水管钻井技术,重点阐述全程无隔水管井下钻具的稳定性分析计算方法及结果,可为日后无隔水管钻井钻具安全性分析提供一定借鉴和指导。

Drilling in the open water without installing deepwater riser is called Riserless Mud Recovery(RMR)technology.It has the advantages such as easy operation and time saving.RMR is one of the important trends for development of deepwater drilling technology.But RMR is also susceptible to superposition of many complex factors such as deep sea waves,currents and rig heave,causing string bending,string fatigue,and even result in the downhole complex accidents.The mechanical stability of drill string in RMR drilling operation is analyzed,and the research and analysis on the influence effectors such as multiple actions of wave and flow,drilling tool spatial configuration,drilling tool dynamic load are carried out,the guidance for the safety of the drilling tool stability analysis is provide.Combined with a deepwater projects in China with RMR technology,the stability of downhole drilling tool in the whole process of RMR drilling is focused on.The research results provide certain guidance for safety analysis of drilling stool in riserless drilling in the future.