连续循环钻井技术装备与应用

The Technology Facilities of Continuous Circulation Drilling and Their Application

为解决常规钻井在上扣、卸扣时因停止/开始泥浆循环,环空中当量泥浆密度波动较大带来的一系列井下问题,国外开展了连续循环钻井技术研究。所谓连续循环钻井技术,是指在钻井过程中,起下钻接卸单根时,可以不停泵而保持井眼处于连续循环状态的技术。该技术可有效克服因开/停泵造成的井下压力波动,减少因压力波动造成的井下复杂情况及事故,尤其适用于压力敏感井、长水平段水平井、大位移井、深水井、欠平衡井和窄密度窗口井。目前,实现连续循环钻井有两种途径,即采用连续循环钻井系统和连续循环短节技术。连续循环钻井系统采用顶部驱动,利用三重闸板连接器内闸板和旁路管汇的合理开合,保持泥浆不间断流动。连续循环短节技术的研究略晚于连续循环系统,该技术包括二位三通阀短节及快速接头,三通阀短节预先连接在需要连续循环井段的立柱上端,通过转换连接在钻柱中三通阀短节的进液方向,同时配合以旁路循环管线上快速接头与阀短节上侧口的插拔,实现钻井液的连续循环。该工具结构简单,操作灵活,已广泛应用于长水平段水平井、大位移井及高温高压井。

In order to solve the downhole problems of great change of equivalent mud density at annulus created by interrupting circulation for a connection such as making up or breaking out,the foreign companies have researched on continuous circulation drilling.Continuous circulation drilling refers to the wellbore is at the state of continuous circulation with no pumping off when joining and unloading single pipe among tripping in the process of drilling.This technology can make downhole pressure change stop caused by pumping on or off,and make complicated downhole problems and accidents less caused by the pressure change.It fits for pressure-sensitive wells,horizontal wells with long horizontal interval,extended reach wells,deepwater wells,unbalanced wells and wells with narrow density window.There are two types of continuous circulation drilling：continuous circulation system and continuous circulation subs.The former keeps the drilling mud circulating continuously and operates connections functions currently,provided by various drilling equipment,such as top drive connection tool,the coupler,the mud diverter manifold and control system.The later has later research,which consists of two-position three-way valve crossover and automatic coupling.Continuous circulation of drilling fluid may be realized through pre-connection of three-way valve crossover at the top of vertical column of the intervals need to continuous circulation,and fluid-in direction convert under the control of automatic coupling on by-path circulation pipeline and valve crossover.It has simple structure and easy operation,which has been widely applied to horizontal wells with long horizontal interval,extended reach wells,and high-temperature and high-pressure wells.