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【标题】Drilling & Exploration Oil Well
【摘要】most oil wells are drilled with rotary method. in this method, a tower holds the drill string, consisting of a series of tubes attached. the chain linking it to the bank spins rotating in the floor of the tower. the drill bit at the end of the chain usually consists of three bevel gears with hardened steel teeth. the drill is brought to the surface by a continuous circulating fluid system driven by a pump. read more... (10-23 05:18)
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