多项选择题
A.金刚石钻头 B.刮刀钻头 C.牙轮钻头 D.铣齿钻头
A.762mm(30”) B.889mm(35”) C.952.5mm(37-1/2”) D.1016mm(40”)
A.台肩 B.螺纹 C.套管本体 D.丝扣油