EARTH-BORING TOOLS ATTACHABLE TO A CASING STRING AND METHODS FOR THEIR MANUFACTURE

摘要

Casing bits include a crown having a substantially hollow interior. The bit crown has blades over a face portion thereof, the blades including a plurality of cutting elements attached thereto. The bit crown further includes a composite inlay (85) positioned at least within the substantially hollow interior. Casing bits also include case hardened outer surfaces radially outside the drill-out region. Casing bits further include short- substrate cutting elements. Methods of forming a casing bit are also disclosed.