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Initial Drill for Re-Entry - This 14 7/8 inch four roller cone tungsten carbide insert roller bit is used to drill the initial hole after the re-entry cone has been landed on the ocean bottom. It is used to run the 16-inch casing which is hung below the cone. Then comes the 11 3/4-inch casing necessary to prevent deep penetration holes from filling up with debris. A similar 10-inches in diameter is used to drill the remainder of the hole.

Initial Drill for Re-Entry - This 14 7/8 inch four roller cone tungsten carbide insert roller bit is used to drill the ini...