| Title | STRATIGRAPHIC RESERVOIRS: A SIGNIFICANT FUTURE RESOURCE IN THE U.S. |
|---|---|
| Authors | R. Allis |
| Year | 2019 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | stratigraphic reservoirs, sedimentary resources, heat flow, permeability, basins, Basin and Range, Cove Fort |
| Abstract | If there is to be renewed growth in geothermal power generation in the U.S. that competes with the growth in wind and solar photovoltaic (PV) power, developments need to be on a scale of ~100 MW. Stratigraphic reservoirs are scalable because of the conductive thermal regime, and the predictable characteristics of the reservoir units on a basin scale once a successful confirmation well has been drilled. However, based on economic modelling by Mines et al. (2014), the target depth range for these reservoirs is 2 – 4 km and temperatures need to be at least 150℃ to 200℃. Reasonable assumptions for reservoir and power station characteristics yield a levelized cost of electricity of 10c/kWh. If recent technological advances in drilling for tight oil and gas can be adapted then it should be possible to significantly reduce the cost and make geothermal more competitive. Deep, lateral groundwater flow in high-permeability stratigraphic units in the eastern Basin and Range Province has swept heat and lowered basin temperatures. Two examples from Utah are examined and demonstrate exploration strategies need to integrate subtle basin-scale groundwater movement with the thermal regime in order to identify the best regions for locating viable stratigraphic reservoirs. In view of the challenging time for new geothermal projects in the U.S, it is essential that government-funded research focus on development issues for both enhanced geothermal systems and stratigraphic reservoirs. |