Performance of low-enthalpy geothermal systems: Interplay of spatially correlated heterogeneity and well-doublet spacings
Performance of low-enthalpy geothermal systems: Interplay of spatially correlated heterogeneity and well-doublet spacings
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DOI：
10.1016/j.apenergy.2019.113569
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发表时间：
2019-11-01
期刊：
影响因子：
11.2
通讯作者：
Nick, Hamidreza M.
中科院分区：
文献类型：
--
作者：
Babaei, Masoud;Nick, Hamidreza M.
低焓地热系统通常部署在沉积地质环境中，其特征是沉积引起的显著水平的非均质性。在本文中，现实水平的异质性的形式不同的孔隙度方差和空间相关长度被认为是一个三维地热系统。使用2600计算密集型数值模拟的两个双峰放置在棋盘图案，以及和双峰间距的影响，低焓地热系统的性能指标进行了研究。模拟强烈支持，在不同的异构系统中，操作的寿命较短，并根据各向同性或各向异性的相关异质性，寿命不同。最值得注意的是，与各向同性相关的异质性相比，各向异性相关的异质性可以对操作的寿命产生积极影响（通过使冷水羽流转向）或负面影响（通过促进冷水羽流的早期突破）。我们还计算了被指定为“许可证区域”（冷水前锋达到或发生1摄氏度阈值温度下降的地方）的威尔斯周围区域的边界。通过这样做，它被发现，运营商可以承担更大的范围（高达50%）的含水层的许可证面积比传统的假设。为了最大限度地减少异质性对操作的影响，发现最佳做法是将双峰放置在与威尔斯相同的间距中。此外，它被发现，井的距离可以显着短于通常实现的异质地热含水层。
The low-enthalpy geothermal systems are commonly deployed in sedimentary geological settings that feature significant levels of deposition-induced heterogeneity. In this paper, realistic levels of heterogeneity in the form of varying porosity variance and spatial correlation lengths are considered for a 3D geothermal system. Using 2600 computationally intensive numerical simulations of two doublets placed in a checkboard pattern, the influence of well and doublet spacings on performance metrics of low-enthalpy geothermal systems are investigated. The simulations strongly support that in varyingly heterogeneous systems, the lifetimes of operation are shorter, and depending on isotropicity or anisotropicity of correlated heterogeneity, the lifetimes vary. Most notably the anisotropically correlated heterogeneity can lead to either positive impact (by diverting the cold water plume) or negative impact (by facilitating an early breakthrough of cold water plume) on the lifetime of the operation compared to isotropically correlated heterogeneity. We also calculate the boundary of the region around the wells designated as the "license area" (where the cold water front reaches to or where a threshold temperature drop of 1 degrees C occurs). By doing so, it is found that the operator can assume larger extents (of up to 50%) for the license areas of the aquifer than the ones conventionally assumed. To minimize the impact of heterogeneity on operation, the best practice was found to place the doublets in the same spacings as of the wells. Moreover, it is found that the well distance can be significantly shorter than what is commonly realised for heterogeneous geothermal aquifers.