The following maps can be viewed in the Map viewer:
| Map | Unit | Description |
|---|---|---|
| Top depth | m | depth of the top of the aquifer |
| Thickness P | m | gross thickness of the aquifer |
| Permeability P | mD | permeability of the net aquifer |
| Net-to-gross | - | net-to-gross ratio of the aquifer |
| Transmissivity P | Dm | product of thickness, net-to-gross and permeability |
| Temperature | °C | temperature at mid aquifer depth |
| Flow rate P,S | m³/hr | production and injection flow rate |
| Power P,S,H | MWth | geothermal power of the doublet |
| Heat in place | GJ/m² | initial heat content of the aquifer (see below) |
| Potential recoverable heat | GJ/m² | heat that could theoretically be extracted without technical or economic constraints (see below) |
| Technical potential S,H | - | technical potential based on subsurface conditions and doublet parameters (see below) |
| Economic potential S,H | - | potential constraint by technical and economic limitations |
| 'White spots' | - | transparency overlay indicating data availability |
P: p90-p50-p10 maps
S: Alternative well stimulation map
H: Alternative heat pump map
Heat In Place (HIP) (PJ/km², same as GJ/m²):
The heat content of the reservoir (cf. Muffler & Cataldi, 1978). The HIP is the maximum theoretically extractable heat in the aquifer:
HIP = γ · (Tres - Tsur) · h
Where:
γ = total heat capacity (GJ/m²), defined as γ = Φ · Cw · ρw + (1 – Φ) · Cr · ρw
Tres = reservoir temperature (°C)
Tsur = average surface temperature (°C)
h = thickness (m)
Φ = porosity (-)
Cw = heat capacity water (J/kg °C)
ρw = water density (kg/m³)
Cr = heat capacity reservoir (J/kg °C)
ρr = rock density (kg/m³)
Potential Recoverable Heat (PRH) (PJ/km², same as GJ/m²), modified from Van Wees et al. (2012):
The calculation of the theoretical potential involves a simple volumetric calculation of Heat in Place, corrected for application specific constraints of minimum production temperature and return temperature.
Technical potential:
The technical potential is equal to the theoretical potential multiplied by the ultimate recovery (UR). For the UR it is assumed that for legal reasons a doublet is oriented in a rectangle which encloses the circles centered around the injector and producer well at reservoir level. The circles touch one another half way between. In such a doublet layout approximately 50% of the heat enclosed in the rectangle can be technically recovered before thermal breakthrough occurs (cf. Gringarten, 1978). The rectangular layout will not be ideal when multiple doublets have to be planned in an area of limited extent and will thus leave unrecovered heat behind. Considering these effects, it is assumed that the UR is about 33%.
In addition the technical potential corrected for UR is divided over a 30 year period, representative for the expected exploitation time. These maps give an indication of heat demand density (GJ/ym²). For an average house assuming a 100m² surface area (as in urbanized areas with a mixture of houses and apartment buildings) and a heat demand of 33 GJ/y, a PRH of 0.33 would suffice to supply heat demand from a geothermal doublets for at least 30 years.