ANDRILL: ANtarctic geological DRILLing
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Drill Rig
The ANDRILL drilling system operated during the MIS and SMS projects is based around a drilling rig constructed by UDR in Brisbane. This type of rig is commonly used in minerals drilling, but has been customized for ANDRILL scientific requirements and for Antarctic conditions.
Customization includes:
  • Reconfiguration of the main winch for a double line pull to deploy sea riser casing, which weighs up to 30 tons.
  • Tide compensation to allow for up to 1.5 meters of vertical tidal movement of the ice shelf or sea-ce platform.
  • Enclosure to provide a warm environment for workers and equipment on the drill floor.
  • Separation of the rig hydraulic power pack (in an insulated container) and the drill mast and winches to provide the best heated location.

The entire system can be broken down into components allowing transport on sledges. The rig components can be airlifted. Some parts of the system, such as the drill platform and catwalk, have been designed and fabricated to incorporate sledge bases for ease of transportation across snow and ice.
Aside from the drill rig itself, other components of the drilling system include:
The drill platform, which supports and encloses the drill rig, and provides the location for the tide compensation system and the hot water drilling system.The jack-up drill platform was designed by Opus (Christchurch) and constructed by Goughs Engineering in Christchurch. The base of the platform is a 13-meter long sledge that can be towed across snow and ice in Antarctica. The platform jacks up three metres to allow space for tidal movement of the ice when the drill pipe is connected to the sea floor.
The catwalk sledge & rod ramp, which provide the staging area for the sea riser and drill pipe as they go into and come out of the hole, and also where the core is first taken out of the core barrel. Pegasus Engineering in Christchurch fabricated the Catwalk sledge and Rod Ramp. The catwalk sledge is 12.5 meters long. The rod ramp can be hauled into its location between the drill rig floor and the catwalk by using the winches on the drill rig. The catwalk and rod ramp can accommodate 3, 6 or 9-meter lengths of pipe.
Drill Rig Catwalk img
Drill fluids (mud) system pic
The drill fluids (mud) system, which provides a fluid for cooling the drill bit and lifting drill cuttings from the base of the hole. Cuttings are removed from the fluid using a centrifuge and other systems, so that the cleaned fluid can be reused. The entire system is based on the use of sea water and environmentally acceptable additives to provide a fluid of a suitable viscosity and weight. Once cuttings have been removed, the 'mud' is returned to the system for reuse. The fluid is pumped to the drill rig from the drill fluids system, which is housed in three ISO containers that are linked to the catwalk sledge. Waste heat from the boilers is ducted to the other parts of the system.
The cementing system, which can supply cement to anchor the sea riser to the sea floor, case the hole, to plug off the hole at the completion of drilling. The cementing system is housed in a container adjacent to the catwalk along with some of the drill fluids equipment, and was also refurbished/built by Webster Drilling & Exploration. It incorporates a palletized batch cementing system consisting of cement mixing tank, hydraulic mixer and cement pump, and an electric/hydraulic power pack (reassembled from CRP hydraulic components) to power the cement system and mud tank agitators. The cement system can mix a batch of 6-700 liters of cement.
Power supply, which is in two parts: (1) the hydraulic systems, which supply the drill rig, and (2) the electrical system supplying the drill fluids and other ancillary systems. The 315 horsepower hydraulic power pack for the Drilling Rig is housed in a container which sits next to the platform and is connected via several hydraulic hoses to the rig. The drillsite also has two generators for supply to the drill fluids and other auxillary systems. These have a combined capacity of 175kVA.
Hot Water Drilling system, which will make a hole through approximately 100 meters of shelf ice, and keep the hole open around the sea riser pipe to prevent any pressure from the ice shelf.
The Hot Water Drill system was designed and built in New Zealand, with hoses supplied by IVG in Italy, and consists of several major components:
  • an initial surface water supply (melted snow on site);
  • boilers to heat the low pressure primary heating circuit;
  • a secondary high pressure circuit with heat exchangers and high pressure pump;
  • a high pressure pump suitable for heated water;
  • a submersible pump for water recirculation; and
  • flexible hoses, winches and jetting tools.
  • HWDS Drill Rig pic
    The Hot Water Drill System uses a succession of progressively larger tools to make the hole through the ice shelf. The first tool (the pilot lance) jets water down through a small nozzle, making a hole approximately 100 mm in diameter. The second tool is the reaming lance, which shoots water back up the hole to ream the hole out to as much as 600 mm as it is lowered. The third tool is the ring reamer, which can jet water upwards or downwards, or recirculate hot fluid inside the tool. The ring reamer is designed to keep the hole open while drilling is going on, and can run up and down the hole melting ice while the sea riser is in place.