Geothermal operations are expanding and increasingly contributing to the current energy supply. Assessing the long-term operable lifetime of these projects is complicated as the reservoirs they produce from are often deep and subsurface properties are uncertain and spatially variable. The minimum lifetime of a geothermal project usually considers the heat in place in a geothermal reservoir, but not the heat flow from the confining layers into the reservoir during operation. For the economic feasibility and optimal design of a geothermal project it is the key to capture this process, as this allows more accurate prediction of the long-term extraction temperature. Previous studies are not conclusive on the contribution of vertical recharge from the confining layers. This research evaluates the contribution of recharge to the heat production for geothermal projects. In a simulation study with an idealised, homogeneous geothermal system, the reservoir thickness, well placement and production rate are varied to investigate their respective influence on thermal recharge. The results show that the recharge from the vertical confining layers may contribute considerably to the total energy output of a geothermal well. Due to recharge, geothermal systems produce more heat than the heat in place and under specific conditions the produced heat can be more than five times as large. The largest contribution of the recharge of vertically confining layers can be expected under conditions of thin reservoirs and a long interaction time between the injection water and confining layers (i.e. large well spacing, low production rate). The insights of this study may help to optimise the design and operation of individual geothermal projects for optimal utilisation of a geothermal reservoir for energy supply.

地热业务正在扩大，并正在为当前的能源供应做出越来越大的贡献。评估这些项目的长期可使用年限很复杂，因为它们所生产的储层通常很深，地下属性不确定且空间可变。地热项目的最小寿命通常考虑地热储层中的热量，而不考虑运行期间从约束层进入储层的热流。对于经济可行性和地热项目的最佳设计，捕获此过程至关重要，因为这可以更准确地预测长期开采温度。先前的研究对于约束层垂直补给的贡献尚无定论。这项研究评估了补给对地热项目供热的贡献。在一个理想的均质地热系统的模拟研究中，改变了储层厚度，井位和生产率，以研究它们各自对热力补给的影响。结果表明，垂直约束层的补给可能对地热井的总能量输出有很大贡献。由于补给，地热系统产生的热量要多于就地产生的热量，在特定条件下，产生的热量可能是其热量的五倍以上。在薄层储层和注水层与约束层之间的相互作用时间较长的情况下（例如，较大的井距，低生产率）。这项研究的见识可能有助于优化单个地热项目的设计和运行，以最佳利用地热库作为能源供应。