| 摘要 |
A method and apparatus for a drilling with casing includes therewith a drill shoe (10) configured for later drilling through thereof in situ, with cutter s retainable thereon in response to the forces encountered during borehole drilling, yet moveable from the envelope through which the later drill shoe will pass when cutting through the in situ drill shoe (10). The drill shoe (10) includes one or more profiles thereon, into which blades (26) carrying the formation drilling cutters are disposed. The profiles include at least o ne projection thereon, which is received within a mating slot in the blades. Th e blades (26) also may be configured to have opposed sections which are configured with respect to one another to have an included angle (136) of le ss than ninety degrees.
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