Abstract Recharge mechanism and water–rock interaction (WRI) along the recharge flows in a transitional geothermal system that characterize the chemical and physical properties of vapor and liquid phases, has not yet been fully understood due to complexities of fluid origin and geologic structure. To clarify the fluid origin and WRI processes in the system, this study applied hydrogen and oxygen isotope, B, Cl, and rare alkali metals analyses by considering fractionation characteristics of 18O in rocks and liquid phases, and correction of δ2H and δ18O values in the steam composition. The investigation were done by using 20 samples collected from liquid-dominated, vapor-dominated, and two-phase wells in one of transitional reservoir fields in West Java, Indonesia. The isotopic fractionation factors calculated from a single-step steam separation clearly divided the samples into four zones: boiling parent fluid, vapor, condensate fluid, and diluted steam-heated fluid. The parent fluid that has initial Cl− concentration of 10,000 mg/kg and low water-rock ratio of W/R ≤ 0.2 compositions was found to be the most essential part of the recharge system. Recharge mechanism involves meteoric water from the elevation of 1200 m – 1300 m a.s.l. infiltrates deeply through NE-SW regional faults, and becomes the parent fluid in the reservoir. The residual fluid after boiling of the parent fluid remains in the liquid reservoir with W/R ≤ 0.2, while the vapor phase forms a parasitic steam cap above the liquid reservoir with 0.2 ≤ W/R ≤ 0.7.

中文翻译：

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考虑水-岩相互作用，通过氢氧同位素分析确定过渡地热场的补给区和机制

摘要 由于流体成因和地质结构的复杂性，过渡性地热系统中沿补给流的补给机制和水岩相互作用（WRI）尚未完全理解，该系统表征了气相和液相的化学和物理特性。为阐明系统中的流体成因和 WRI 过程，本研究应用氢氧同位素、B、Cl 和稀有碱金属分析，考虑了岩石和液相中 18O 的分馏特征，并修正了 δ2H 和 δ18O 值。蒸汽组成。调查是通过使用从印度尼西亚西爪哇的一个过渡油藏油田中以液体为主、以蒸气为主和两相井收集的 20 个样品进行的。从单步蒸汽分离计算的同位素分馏因子将样品清楚地分为四个区域：沸腾母体流体、蒸汽、冷凝流体和稀释的蒸汽加热流体。发现初始 Cl− 浓度为 10,000 mg/kg 且水岩比 W/R ≤ 0.2 的母液是补给系统中最重要的部分。补给机制涉及海拔1200-1300m的大气水通过NE-SW区域断层深入渗透，成为储层母液。母液沸腾后的残余流体留在储液器中，W/R ≤ 0.2，而气相在储液器上方形成寄生蒸汽盖，0.2 ≤ W/R ≤ 0.7。冷凝流体和稀释的蒸汽加热流体。发现初始 Cl− 浓度为 10,000 mg/kg 且水岩比 W/R ≤ 0.2 的母液是补给系统中最重要的部分。补给机制涉及海拔1200-1300m的大气水通过NE-SW区域断层深入渗透，成为储层母液。母液沸腾后的残余流体留在储液器中，W/R ≤ 0.2，而气相在储液器上方形成寄生蒸汽盖，0.2 ≤ W/R ≤ 0.7。冷凝流体和稀释的蒸汽加热流体。发现初始 Cl− 浓度为 10,000 mg/kg 且水岩比 W/R ≤ 0.2 的母液是补给系统中最重要的部分。补给机制涉及海拔1200-1300m的大气水通过NE-SW区域断层深入渗透，成为储层母液。母液沸腾后的残余流体留在储液器中，W/R ≤ 0.2，而气相在储液器上方形成寄生蒸汽盖，0.2 ≤ W/R ≤ 0.7。补给机制涉及海拔1200-1300m的大气水通过NE-SW区域断层深入渗透，成为储层母液。母液沸腾后的残余流体留在储液器中，W/R ≤ 0.2，而气相在储液器上方形成寄生蒸汽盖，0.2 ≤ W/R ≤ 0.7。补给机制涉及海拔1200-1300m的大气水通过NE-SW区域断层深入渗透，成为储层母液。母液沸腾后的残余流体留在储液器中，W/R ≤ 0.2，而气相在储液器上方形成寄生蒸汽盖，0.2 ≤ W/R ≤ 0.7。