张力腿平台水下丛式井口圆形布局方法研究

Research on the round layout design approach of subsea cluster wellheads for TLP

张力腿平台(TLP)水下丛式井口布局设计关系到立管服役期间的安全性,是含有丛式井口平台设计过程中考虑的主要因素。根据TLP立管安装、钻井以及防碰等要求,考虑尾流效应对丛式立管的影响,研究水下丛式井口布局设计准则,对丛式井口—立管系统进行碰撞分析以确定水下井口间距阈值,提出水下丛式井口圆形布局方法和相应的布局设计流程。通过算例对计算方法进行了具体运用。研究表明:与目前采用的“等边三角形网格”方法相比,水下丛式井口圆形布局方法可允许水下整体基盘安装位置误差达到水下井口间距阈值的20%,立管的最大倾角可达到0.5°,安装作业窗口增加1倍以上。本方法对水下整体基盘安装位置误差的容错能力强,能有效扩大丛式立管钻井和安装作业窗口,提高丛式立管作业安全性,研究结果可为TLP丛式井口的设计提供参考。

The subsea cluster wellheads layout design of Tension Leg Platform(TLP)is closely related to the safety of riser in operation,and also is the main consideration for the design of cluster risers and platform.In this paper,based on requirements for installation,operation and anti-collision of the cluster risers,considering the wake effect,the subsea wellhead spacing threshold is determined by analyzing the collision of cluster wellhead-risers system,and the design criterion of subsea wellhead layout is studied,and the round layout design approach and design procedure of subsea cluster wellheads are proposed.The specific application of the proposed approach is illustrated by an example.The results show that,compared to the equilateral triangular mesh method,the round layout design approach of subsea cluster wellheads allow the installation position error of subsea template to reach the 20%of the subsea wellhead spacing threshold,and the max inclination angle of riser to reach 0.5°,thus the installation operation window of the risers increases more than 1 times.The proposed approach has stronger fault-tolerant ability for the installation position error of subsea template,and larger drilling and installation operation window for cluster risers.Consequently,the operation safety of cluster risers is improved.The proposed approach and related results could provide reference for the design of cluster wellheads.