[油气] 钻铤公称质量 nominal mass: 名义质量drill collar: 防偏钻杆; 钻挺; 钻头钻油台; 钻铤decentralized drill collar: 偏心钻铤drill collar annulus: 钻铤环空drill collar bore: 钻铤内孔下载手机词典可随时随地查词查翻译