Wayang Windu geothermal field, which is situated in quaternary volcanic rock, has been delivering 227 MW of electricity and is planned to be developed in near future. Isotope and geochemistry study has been done to support understanding of the system. Samples were taken from thermal manifestations and production wells (two-phase and dry steam wells) to analyse its isotope and chemical compositions. Most of the hot springs are bicarbonate type and have neutral pH values, except for steam heated waters found near fumarolic fields, which are acid sulfate type waters. Deep brine fluids are of mature chloride type, while other deep dilute fluids are bicarbonate type indicates the existance of condensate layer. Solute and gas geothermometer calculation showed good agreement with measured temperature, i.e., 280–300 °C. However, gas-gas equilibria calculation showed increasing T and decreasing y (steam fraction) compare to previous study which indicates contribution form hotter source with high liquid saturation. Aside from different recharge area of thermal manifestation and production wells, the isotopes composition also shows physical processes in reservoir, i.e., adiabatic boiling, steam separation at different temperature (140–260 °C) and steam fraction (0.30–0.65), and also mixing process with meteoric water.

位于第四纪火山岩中的Wayang Windu地热田已提供227兆瓦的电力，并计划在不久的将来进行开发。已进行同位素和地球化学研究以支持对该系统的理解。从热表现和生产井（两相和干蒸汽井）中取样，以分析其同位素和化学成分。大多数温泉是碳酸氢盐类型，pH 值为中性，除了在喷气沼泽地附近发现的蒸汽加热水是酸性硫酸盐类型的水。深层盐水流体为成熟的氯化物类型，而其他深层稀释流体为碳酸氢盐类型，表明存在凝析层。溶质和气体地温计的计算结果与测量温度非常吻合，即 280-300 °C。然而，气-气平衡计算表明，与之前的研究相比，增加了 T 和减少了 y（蒸汽分数），这表明来自具有高液体饱和度的更热源的贡献。除了热显象和生产井补给区不同外，同位素组成还显示出储层中的物理过程，即绝热沸腾、不同温度（140-260℃）和蒸汽分数（0.30-0.65）下的蒸汽分离，以及与大气水混合的过程。