Fast drilling tools and age validation
Based on the glaciological characteristics established, WP2 will propose several sites where WP3 will deploy a set of different rapid reconnaissance tools able to validate the suitability of the investigated sites for a deep drilling operation. WP3 will also provide means for age validation through a range of dating methods and to build the best strategy for dating the “Oldest Ice” core.
RADIX from UBERN
The design of RADIX is based on the established technique of coiled tubing drilling (Clow and Koci, 2002, Schwander et al., 2014) in forward flow mode. A downhole hydraulic motor is powered by high-pressure fluid in the coiled tubing/hose, and cuttings are flushed to the surface along the space between the hole wall and the tubing/hose. At surface ice cuttings are separated from the fluid, which is recycled to the hydraulic pump. Ice cuttings are sampled sequentially for further analysis. The drilling fluid also serves to maintain a balanced hydrostatic pressure in the hole. The goal is to optimize the system for low weight and good speed of penetration. The fluid represents a significant part of the total weight and cost of a drilling. Therefore we set minimizing the hole size as a major constraint of the design. Hole size, hydraulic hose dimensions, hydraulic pressures, power for drilling, drilling speed, etc., are closely interrelated.
Clow GD and Koci B (2002) A fast mechanical-access drill for polar glaciology, paleoclimatology, geology, tectonics and biology. Mem. Natl Inst. Polar Res., Special Issue 56, 5–37
J. Schwander, S. Marending, T.F. Stocker, H. Fischer, RADIX: a minimal-resources rapid-access drilling system, Annals of Glaciology 55(68) 2014 doi: 10.3189/2014AoG68A015
Main system parameters:
- Hole diameter: 20 mm
- Drill diameter: 50 mm
- Hydraulic motor: 3D laser sintered progressive cavity displacement motor: Diameter: 15 mm, Mechanical power: 50 W, nominal rpm: 15 sec-1
- Hydraulic pump: Triplex piston 2L/min, 200 bar
- Hydraulic hose: 3000 m; od/id: 14/8 mm
- Nominal drilling speed: 10 mm/sec
- Cycle time for 3000 m hole including logging: 2 weeks.
- Fluid requirement: 1000 kg/hole (optional recovery of fluid after drilling)