Recovery Factor of Geothermal Resources

Geothermal resources are often exploited by multiple independent operators with potentially conflicting objectives. As a result, exploration licences are issued on a first-come, first-served basis. Alternatively, doublet deployment could be based on a regional masterplan that aims to optimise heat recovery, which is common-practise in the hydrocarbon industry. This study compares the impact of geothermal well deployment following those two different approaches on (1) recovery efficiency, (2) Net Present Value and (3) its CO₂ footprint. We conduct heat transfer simulations of exploitation of the Lower Cretaceous Sandstones in the West Netherlands Basin. This Hot Sedimentary Aquifer is the main target for ongoing geothermal exploitation in the Netherlands. In the simulations, doublet wells were deployed following the ‘first-come, first-served’ doublet deployment, which is based on the location of two currently active doublets. In addition, simulations are conducted in which doublets are deployed with a hypothetical, regional coordinated, optimised ‘masterplan’ approach. Results of this study indicate that there is significant scope to optimise doublet density and recovery efficiency of geothermal heat when doublets are deployed in a regionally coordinated ‘masterplan’. This is because with a ‘first come, first served’ approach, doublet placement and design mainly aims to meet targets of individual operators and remaining space might be too small for new operators leaving much of the resource untapped. Optimisation of doublet deployment and licensing is required to make geothermal a more significant player in a future low-carbon energy mix. Firstly, this would require new tailor-made geothermal subsidy schemes that promote deployment optimisation over the ‘first come, first served’ deployment. Secondly, it requires tailor-made legislations that accommodate for increased interference between operators that is inevitable with denser doublet deployment. Finally we show that geothermal exploitation has a very low carbon footprint, highlighting its value to meet low-carbon energy targets. This study could assist in the development of realistic geothermal exploitation targets and the development of required financial and legislative support schemes to promote more efficient use of the enormous amounts of geothermal heat.