A.1~2 B.3~5 C.10~15 D.60~90
A.起下鉆桿 B.起下鉆鋌 C.空井 D.鉆進(jìn)
A.容易產(chǎn)生水擊現(xiàn)象 B.關(guān)井時(shí)間比較長(zhǎng) C.對(duì)井口沖擊比較小 D.關(guān)井時(shí)間比較短