Table 1
. Comparison of underreamer and bi-center reamer casing and drill bit specifications.|
Casing OD (in.) |
Casing weight (lb/ft) |
Casing drift ID (in.) |
Buttress coupling OD (in.) |
Drill bit option (in.) |
DDI bi-center drill-in casing model number |
HOC underreamer (in.) |
|
| DTU 95 | DTU 1175 | ||||||
| 20 | 94 | 18.936 | 21 | Jet-in | B#182x215 | ----- | 22 |
| 16 | 75 | 14.936 | 17 | 18.5 | B#145x185 | ----- | 20 |
| 13.375 | 54.5 | 12.459 | 14.375 | 14¾ | B#122x146 | 14¾ | ----- |
| 10.75 | 40.5 | 9.894 | 11.75 | 12¼ | ----- | 14¾ | ----- |
Notes: OD = outer diameter; ID = inner diameter; DDI = Downhole Design, Inc.; HOC = Hole Opener Corporation; DTU is part of the model number.