| 摘要 |
Oil well drilling apparatus for drilling deep boreholes. The apparatus includes a high frequency, high voltage, AC generator at the surface of the ground which is connected to an electromagnetic hammer drill bit located at the bottom of the borehole. Electric current is conducted along a special drill string to the electromagnetic hammer drill located at the bottom of the hole. The drill string is a co-axial electrically conductive drill pipe which forms spaced annular current flow paths to the downhole electromagnetic hammer drill, while at the same time, drilling fluid flows along an axial flow path to the vibrating bit located at the bottom of the borehole. A special directional drill collar is positioned immediately above the electromagnetic hammer drill for controlling hole deviation. The co-axial electrically conductive lightweight drill pipe, the electrically conducting control deviation drill collars, and the electromagnetic hammer drill bit and pulse transformer each forms a subcombination of the present invention; and, jointly comprise a new method and apparatus for forming boreholes.
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