- Volcanic Geothermal Systems would require a series of holes in the ground to gather data required to progress subsurface investigations. After having done geological and geophysical field work and analysing the results in models, targeted well locations would have been identified.
- Prior to beginning to drill wells, it would be preferred to drill a number of relatively shallow, small diameter boreholes (<~100m deep, <4in diameter) to check the shallow subsurface integrity and identify any shallow hazards for the subsequent installation of well surface casing and conductors.
- Some locations could require shallow, small diameter wells to be drilled down to ~250-500m depth to obtain thermal gradient data. These wells may utilise some form of casing strings such as this example:
- 5-1/2in Surface Casing (driven to 10m),
- 3-1/2in Intermediate Casing (to 50m),
- small diameter tubing to depth,
- The small diameter tubing to depth would be initially used for cementing purposes, then a wiper plug would be pumped with water to displace cement in the tubing. A top set valve would be used to give access to the tubing for thermal measuring equipment.
- No BOPE would necessarily be used for these wells which could stop at a determined temperature limit (~75°C)
- The use of relatively small, mobile mineral exploration diamond coring drill rigs would be an easy, economic way to get this initial information and logistical challenges to access the site would be mitigated..
