| 释义 |
ˈunderreamer Oil Industry.
[under-1 5 b.]
A drilling bit that can be used to drill a hole below the casing, of sufficient size for the casing to be lowered further. So ˈunderreaming vbl. n.
1912Under-reamer [see rotary a. 2 c]. 1922D. T. Day Handbk. Petroleum Industry I. 246 Underreaming is accomplished through the medium of an ingeniously designed bit (termed an ‘underreamer’ because it reams under the casing). 1939D. Hager Fund. Petroleum Industry viii. 186 If for any reason the hole has been cased at a certain depth and it is necessary to carry the same diameter of hole deeper without removing the casing, an underreamer is used. |