Ditch Witch OnGrade - Manual (Page 45)

Systems and Equipment - 44
OnGrade Operator’s Manual
Downhole Tools
CMW
Process
The tools, fluid rate, drilling fluid and process used for backreaming and pulling in pipe will vary based on
soil conditions and operator’s experience and knowledge of the soils in the area. A few key points to
consider are:
• Make as few passes through the bore hole as possible. The walls of the bore may soften with the
addition of drill fluid and additional passes may cause the backreamer or tooling to sink below the
desired line for the bore.
• Monitor the flow of spoils from the far end of the bore hole during backreaming. If spoils are not leaving
the bore, the drilling fluid could frac-out and cause the ground to hump. This hump in the bore could
cause the installed pipe to move up and create an unacceptable dip in the installation.
• If drilling unit operator cannot be confident of keeping spoils return while pulling in the product behind
the backreamer, backream the hole without pulling in pipe. Push back through the hole with pilot drill
head and then pull in product without reaming.