Abstract Stable isotope compositions in groundwater are widely used to understand hydrological processes. To infer changes in isotope composition in the subsurface due to interacting processes such as dispersion, chemical reactions, and phase changes, numerical simulations were employed to relate the isotope composition in the groundwater to that in the recharge water. It was early identified in the laboratory that the variation of temperature and pressure can lead to the isotope fractionation in water. This indicated that for geothermal aquifers with fluid density contrasts due to the variation of temperature and pressure, the isotope fractionation among varying-density fluids can occur. However, this effect has not been considered in regional-scale geothermal aquifers previously. This study numerically investigated the relationship between density-contrasts and the distribution of stable isotope in confined aquifers with temperatures up to 180 °C and depths of

中文翻译：

---

区域尺度承压地热含水层密度变化稳定同位素分馏数值模拟

摘要 地下水中的稳定同位素组成被广泛用于了解水文过程。为了推断由于分散、化学反应和相变等相互作用过程导致的地下同位素组成的变化，采用数值模拟将地下水中的同位素组成与补给水中的同位素组成联系起来。实验室很早就发现温度和压力的变化会导致水中的同位素分馏。这表明，对于由于温度和压力变化而导致流体密度差异的地热含水层，不同密度流体之间可能发生同位素分馏。然而，以前在区域尺度地热含水层中并未考虑这种影响。