东海某井起下钻遇阻及托压现象钻柱力学分析

Mechanical Analysis of Drill String on Tripping Blockage and Backing Pressure in a Well in East China Sea

何阳子

HE Yangzi

中国石油化工股份有限公司上海海洋油气分公司石油工程技术研究院，上海　200120

Institute of Offshore Petroleum Engineering, SINOPEC Shanghai Offshore Oil & Gas Company, Shanghai 200120, China

东海某定向井在三开12-1/4″井眼钻进过程中多次遇阻并发生托压现象。为分析原因，该文基于有限元方法，建立了定向井钻柱的静力学和动力学计算模型，计算了井筒中起下钻时钻柱的准静态受力，以及旋转钻进过程中钻柱的动态受力情况，系统分析了钻进中遇阻及定向托压的原因。结果表明井斜较大井筒中，底部钻具组合与井壁的平均接触力增大，导致摩阻增大进而发生托压现象。底部钻具组合与井壁的剧烈碰撞引发的井壁脱落掉块导致了遇阻。该文对大斜度定向井钻井过程中预防托压现象提出了合理建议，为东海定向井的安全钻进提供有效的参考。

A directional well in East China Sea has encountered many obstacles and backing pressure phenomena in the drilling process of 3-opening 12-1/4″ hole. In order to analyze the reasons, this paper is based on a finite element method to establish the static and dynamic calculation models of directional well drill string, to calculate the quasi-static force of drill string during tripping and the dynamic force of drill string during rotary drilling, and to systematically analyze the phenomenon of drill string blockage and backing pressure. The results show that in the wellbore with large inclination, the average contact force between BHA and borehole wall increases, leading to the increase of friction and thus backing pressure phenomenon. The violent collision between the BHA and the wellbore caused the blockage because segments fall off the wellbore. In this paper, reasonable suggestions are put forward to prevent backing pressure in the drilling process of directional well with high inclination, which provides effective reference for safe drilling of directional well in East China Sea.

https://doi.org/10.3969/j.issn.1008-2336.2023.03.075