The ODEX Drilling Method

ODEX equipment enables you to drill and case deep holes simultaneously in all types of formation, even those with large boulders. Casing diameters from 108mm (ODEX 85) to 355mm (ODEX 305) can be used in our products range.

The Odex drilling method is based on a pilot bit and eccentric reamer, which together drill a hole slightly larger than the external diameter of the casing tube. This enables the casing tube to follow the drill bit down the hole.

When using ODEX drilling system, part of the impact energy is diverted to the casing tube via a shoulder on the guide device, which in turn impacts a special casing shoe at the lower end of the casing.

In both DTH and top hammer drilling the casing is driven down into the hole without rotation. When the casing enters the bedrock, drilling is stopped briefly, and reverse rotation applied carefully, which causes the reamer to turn in, thus reducing the overall diameter of the drill bit assembly.

When this has been accomplished, the entire drillstring can be pulled up through the inside of the casing tubes, leaving the latter embedded in the bedrock. Drilling can then be continued into the bedrock using a conventional drill string. In difficult conditions, a foaming additive can be added to the compressed air to further improve flushing performance.

Commercially available steel tubes in standard dimensions are used for the casing. They are welded together and left in the ground after the hole has been completed. For applications where the casing is to be reused, it generally pays to use threaded casing tubes.