为: support; stand for更换: renewal; change; replace; tr ...钻头: boring crown; bore bit; dril ...进行: be in progress; be underway; ...起: rise; get up; stand up下: below; down; under; undernea ...钻: drill; auger作业: school assignment强行起下钻作业: snubbing service; stripping-in operations起下钻作业: round trip operations; tripping operation为改变底部钻具组合而进行的起下钻作业: bha trips为换钻头起下钻: bit trips更换钻头: bit change可更换钻头: interchangeable bit过早更换钻头: premature bit change进行短途起下钻: make a short trip井下更换钻头式钻机: changeable bit drill起下钻: make a trip; round trip换钻头: bit change cambio de barrena; bit changing用防喷器在压力下强行起下钻: stripping in and out of the hole短起下钻: short trip刮拭起下钻: wiper trip划眼起下钻: wiper trip扩眼起下钻: reaming trip起下钻方式: trimode