- Exploration and development wells are a major cost component of geothermal energy projects.
- In the exploration phase, when wells are being used to derisk geothermal prospects, it is important to be as economic as possible, so slimhole wells have been increasingly utilised to reduce costs.
- In the development phase, assuming successful exploration, it is important to maximise productivity of the hydrothermal reservoir, so larger diameter wells have been more common to be able to access more enthalpy.
- Multiple exploration wells would have gathered subsurface data and ideally obtained information about hydrothermal reservoir extent, depths, stratigraphy, faults/fracture systems, rock and fluid properties, and heterogeneity. This data used in reservoir modelling and numerical simulations would have helped identify best development well numbers, locations, and configurations.
- Production and injection wells would be located to minimise any adverse interactions. Slightly cooler injection fluids would enter the reservoir to be reheated by conductive and convective heat, but need to be far enough away from production wells to avoid reducing production fluid temperatures. Preferential flow paths from injection wells to production wells need to be avoided. Upflow zones in the wells
