| Answer | Crossword Clue |
|---|---|
| wells | hole drilled in the earth to reach water, oil, etc. |
| well | hole drilled in the earth to reach water, oil, etc. |
| borehole | hole drilled in the earth, as for the purpose of extracting a core, releasing gas, oil, water, etc. |
| boreholes | A deep, narrow hole made in the ground, esp. to locate water or oil |
| waterflood | a flood of water; an inundation to inject water to maintain pressure in a reservoir and to drive the oil, etc towards the production wells |
