摘要 |
According to the invention a flexible drill pipe constructed of a closed pitch cylindrical spiral coil of wire rod, a female tool joint is attached to one end of the coil of wire rod and a male tool joint is attached to the other end. A plurality of wire wound flexible shafts are laid through the coil of wire rod attaching to the female and male tool joints and enclosing a hollow internal support assembly. The wire wound flexible shafts support the coil of wire rod so it can carry high tension loads and not let it over extend its length. The hollow internal support assembly keeps the coil of wire rod from collapsing under high torsion loads, provides a passage way for drilling fluids to be pumped through the flexible drill pipe, and provides an even distribution of flexibility over the length of the coil of wire rod.
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