1, WHY OVERBURDERN DRILLING?
Soft soil is normally drilled with augers or by the rotary method but DTH hammers have
adapted to soft conditions by being able to drill and case the hole simultaneously using an eccentric bit which can be withdrawn on completion of the bore hole, leaving the casing in situ, thus preventing hole collapse.
The systems achieve this by enabling the down the hole drill string and casing to be lowered simultaneously. A down the hole hammer is used to which is fitted a driver and eccentric bit.
2, How the Overburden Drilling system works ?
http://hiphotos.baidu.com/sinodrills/pic/item/f230df77d0160924e5565757d40735fae7cd346d.jpg
Drilling into the ground,the eccentric bit rotates outwards to drill
a larger diameter hole than the following casing.
http://hiphotos.baidu.com/sinodrills/pic/item/d49f1533720e0cf36792bbb70a46f21fbf09aa70.jpg
After reaching the required cased depth the drill string is rotated in the opposite direction, the eccentric bit is then withdrawn into thecasing.
http://hiphotos.baidu.com/sinodrills/pic/item/fdccc781f603738ddf2ef96eb31bb051f919ec71.jpg
This enables the entire drill string to be pulled out, leaving the casing in situ in the bedrock
http://hiphotos.baidu.com/sinodrills/pic/item/7f0a122cf8dcd10089d50d6d728b4710b8122f0b.jpg
Drilling can then be continued using a standard DTH button bit through
the casing.
3, the composition of ODEX Overburden drilling system:Guide device, Reamer, Pilot bits, Casing shoe.
The usual ODEX size:
ODEX 90, ODEX 115, ODEX 140, ODEX 144, ODEX 165 , ODEX 190, ODEX 240
3" DTH hammer bits (90mm - 105mm): DHD 3.5, COP 34, COP 32, Mission 30, BR 3, Mach 303,
4" DTH hammer bits (105mm- 130mm): DHD 340/COP 44, COP 42, QL 40, SD 4, Mission 40, XL 4, Mach 44,
5" DTH hammer bits (130mm- 152mm): DHD 350/COP 54, COP 52, QL 50, SD 5, Mission 50, XL 5,
6" DTH hammer bits (152mm- 171mm): DHD 360/ COP 64, COP 62, QL 60, SD 6, Mission 60, XL 6,
8" DTH hammer bits (200mm- 305mm): DHD380, QL 80, SD 8, Mission 80, COP 84;
3, Drill rods diameter range: 76mm, 89mm, 102mm, 114mm, 127mm;
4, ODEX overburden drilling system:
ODEX 90, ODEX 115, ODEX 140, ODEX 144, ODEX 165 , ODEX 190, ODEX 240
5, Symmetrix overburden drilling system and spare parts.
Mr Jack Chan/ Products Manager
Mob: +86-13985434402
Guizhou Sinodrills Equipment Co., LTD.
Web: http://www.sinodrills.net
E-mail: [email protected]
MSN: [email protected]
Tel: +86-851-6821628, 6821268, 6800738, EXT: 8012;
Fax: +86-851-6830552;
