深水低压井口下入工具结构设计与承载特性分析

Configuration design and bearing characteristics analysis on running tool of deepwater conductor wellhead

深水低压井口下入工具是低压井口管柱的唯一平台转移和钻台下入工具,影响着深水导管的安全高效下入作业。为打破国外技术服务公司的长期技术垄断,通过对深水低压井口下入工具的结构设计、工作原理、工作过程及深水钻井平台操作工况、作业程序、作业关键技术难题的研究,设计了一种采用圆头T型卡簧推杆、锥面轴套及卡簧相配合的新型深水低压井口下入工具的锁紧与释放结构;应用该锁紧与释放设计结构并配合安装导向头设计结构,可使下入工具适应于深水恶劣操作工况条件;通过对不同作业工况条件下的承载力学特性分析和操作过程仿真分析,研究了结构系统安全性及工具锁紧与释放过程的可行性;数值模拟分析表明,起吊、下入最危险操作工况条件下,许用应力安全系数分别为3.87、4.98。本研究可为安全、高效地开展深水低压井口头平台转运及下入作业提供一种新的设计思路和方法。

Conductor wellhead running tool is the only operating practice to transfer or to run in/out the conductor pipe on platform deck, and it is a key factor on deepwater conductor running. But the related technologies were monopolized by several monopolistic companies abroad. In this paper, one kind of novel locking and releasing mechanical configuration was presented by studying running tool structure, operating principle, operating procedure, as well as operating behavior on semi-submerged platform, job procedure and technical problems on running.It was constructed with T-shaped-round-tip thrusting rod, pyramidal axle sleeve, and circlip. The locking and releasing mechanical structure equipped with guiding mechanism would qualified the running tool to apply in deepwater harsh operating conditions. The stability, the credibility, and the safety of the running tool were conducted by the study on bearing characteristics, operating simulation and finite element simulation on different operating status. The simulation results show that the safety factor of allowable stress is respectively 3.87 and 4.98 under the condition of transferring working procedure and running-in working procedure. By this way, the high cost of deepwater drilling caused by foreign technological embargo in China could be reduced.