Excentric casing advancement drilling system

  ODEX systems are most economical solutions for casing drilling in average ground conditions. They are very popular with drilling contractors for casing in water wells, geothermal wells, medium mini-type grouting hole of building, dam and harbour project, and shallow micro-piling work. Because of the ingenious reaming wing, the bit is retrievable and can be used again. ODEX is ideal for short holes in homogenous overburden, thanks to outstanding advantages as simple structure, easy operation, retrievable drilling tools, long service life and good quality.

ODEX (short for “Overburden Drilling Excentric”) is also called Stratex, Tubex or ODS. It is an adaptation of the air-circulation DTH hammer. It is with a swing-out eccentric bit to ream the bottom of the casing. And the percussion bit consists of two parts fixed tips: a concentric pilot bit, and behind it is an eccentric reamer bit that swings out to enlarge the borehole diameter during drilling. After the eccentric bit is a guide device that engages a special internal shouldered casing shoe on the bottom of the ODEX casing. The ODEX is thus pulled down by the drill string as the hole is advanced. Cuttings blow up through the annulus gap between guide device and casing shoe to a swivel conducting them onto the ground or to a sample collector.

Drilling characteristics of ODEX systems are essentially the same as for the DTH hammer drilling method, like:

Rapid removal of cuttings;

High penetration rate, especially in resistant rock formation (e.g. basalt);

Easy soil and groundwater sampling during drilling;

Possible to measure yield estimate at selected depth in the formation;

Advantageous in unconsolidated formations with a high risk of caving (this is probably the most important feature).

Specification Overview: