PROCEDURE
Enlarging pilot hole
The pilot hole is enlarged usually approximately 1.5 times the largest outside diameter OD of the pipe string, (up to 30% over cut till 45% depending on the ground conditions) by pulling back increasingly larger reamers, or reaming heads, from the pipe “Exit Point” to the rig side, conventionally defined as “Entry Point”. To achieve the appropriate bore path size it may be necessary to perform several reaming operations.
Generally, all reaming procedures prior to the actual product pipe installation are referred to as Pre Reaming, and the final ream to which the product pipe is connected is referred to as the Back Reaming
fig. 2 Enlarging pilot hole
PROCEDURE DESCRIPTION
