电机驱动式井下环空防喷器的研制及密封性能分析

针对钻井工艺的复杂性及井型、井段的适应性，研制了一种电机驱动式井下环空防喷器，对其结构、控制方式、工作原理进行了介绍；采用有限元的方法对胶筒座封过程中胶筒与套管不同间距的情况进行仿真分析，得到了胶筒的应力变化规律及“快速密封”的座封方式；利用防喷器实验台架模拟井下溢流的方法测得此防喷器的最大封隔压差以及密封过程中的形态变化，测得硬度为90的胶筒在最大压缩量的时候可以封隔25 MPa压差。此电机驱动式井下环空防喷器结构简单，动作迅速，无需频繁起出钻柱进行防喷器更换，能够重复使用，降低总成本，具有较强的实用性。

Design and sealing performance analysis of motor-driven downhole annular blowout preventer

Aiming at the complexity of drilling process and the adaptability of well type and well section, a motor- driven downhole annular blowout preventer was designed, and its structure, control mode and working principle were introduced. The situation of different spacing from packer element to casing in the process of down and seal the packer for the packer element was simulated and analyzed by using the finite element method, and the stress change rule of packer element and the "rapid sealing" way of down and seal the packer were obtained. The maximum packing differential pressure of the blowout preventer and its morphological change during the sealing process were measured by simulating the downhole overflow through the experiment bench of blowout preventer. It showed that the packer element with hardness of 90 can seal 25 MPa differential pressure when adopting the maximum amount of compression. The motor-driven downhole annular blowout preventer has simple structure and rapid action, without frequently tripping out to replace the blowout preventer. It can be reused and lower the total cost, and has strong practicability.