Double Wall Drill Pipes are used in drilling of wells with diameter 84 and 93 mm and depth up to 300 m in soils of II-V drillability classes with seams of soils up to VII drillability class in the fulfilment of all necessary prospecting and geochemical operations, in geological mapping and exploration of deposits of solid minerals.
Drilling of wells is carried out with hydro-transport of the core delivered on the surface along the internal channel of the double drill string.
Technical characteristics of pipes
|Standard size||Pipe||Connector||Length L, mm||Weight, kg||Thread|
|External diameter D, mm||Wall thickness t, mm||External diameter D1, mm||Internal diameter d1, mm||OD of tong recess S, mm|
Mechanical properties of pipes (at least)
|Tensile strength, MPa||539||882||390||882|
|Yield strength, MPa||323||686||255||686|
- Mechanical properties of connectors indicated after the volumetric heat treatment.
- Surface hardness after heat treatment – not less 45 HRC.