A simulation study was carried out to investigate the temporal evolution of H₂S in the Huangcaoxia underground gas storage (UGS), which is converted from a depleted sulfur-containing gas field. Based on the rock and fluid properties of the Huangcaoxia gas field, a multilayered model was built. The upper layer Jia-2 contains a high concentration of H₂S (27.2 g/m³), and the lower layer Jia-1 contains a low concentration of H₂S (14.0 mg/m³). There is also a low-permeability interlayer between Jia-1 and Jia-2. The multi-component fluid characterizations for Jia-1 and Jia-2 were implemented separately using the Peng-Robinson equation of state in order to perform the compositional simulation. The H₂S concentration gradually increased in a single cycle and peaked at the end of the production season. The peak H₂S concentration in each cycle showed a decreasing trend when the recovery factor (RF) of the gas field was lower than 70%. When the RF was above 70%, the peak H₂S concentration increased first and then decreased. A higher reservoir RF, a higher maximum working pressure, and a higher working gas ratio will lead to a higher H₂S removal efficiency. Similar to developing multi-layered petroleum fields, the operation of multilayered gas storage can also be divided into multi-layer commingled operation and independent operation for different layers. When the two layers are combined to build the storage, the sweet gas produced from Jia-1 can spontaneously mix with the sour gas produced from Jia-2 within the wellbore, which can significantly reduce the overall H₂S concentration in the wellstream. When the working gas volume is set constant, the allocation ratio between the two layers has little effect on the H₂S removal. After nine cycles, the produced gas’s H₂S concentration can be lowered to 20 mg/m³. Our study recommends combining the Jia-2 and Jia-1 layers to build the Huangcaoxia underground gas storage. This plan can quickly reduce the H₂S concentration of the produced gas to 20 mg/m³, thus meeting the gas export standards as well as the HSE (Health, Safety, and Environment) requirements in the field. This study helps the engineers understand the H₂S removal for sulfur-containing UGS as well as provides technical guidelines for converting other multilayered sour gas fields into underground storage sites.

对由贫硫气田改建的黄草峡地下储气库(UGS) 中H ₂ S的时间演化进行了模拟研究。根据黄草峡气田岩石和流体性质，建立了多层模型。上层Jia-2含有高浓度H ₂ S(27.2g/m ³ )，下层Jia-1含有低浓度H ₂ S(14.0mg/m ³ )。Jia-1和Jia-2之间还有一个低渗透夹层。Jia-1 和 Jia-2 的多组分流体表征分别使用 Peng-Robinson 状态方程进行，以便进行成分模拟。H ₂ S浓度在一个周期内逐渐升高，并在生产季节末达到峰值。当气田采收率(RF)低于70%时，各循环H _{2 S峰值浓度均呈现下降趋势。}当RF大于70%时，H ₂ S峰值浓度先升高后降低。较高的储层RF、较高的最大工作压力和较高的工作气体比例将导致较高的H ₂ S去除效率。与开发多层油田类似，多层储气库的运营也可分为多层混合运营和分层独立运营。当两层联合建库时，嘉1井产生的脱硫气体可以与嘉2井产生的酸性气体在井筒内自发混合，从而可以显着降低井流中的总体H 2 S浓度_。当工作气体量一定时，两层的分配比例对H ₂ S的去除影响不大。经过9次循环后，产气中H ₂ S浓度可降至20mg/m ³。研究建议结合甲二层和甲一层建设黄草峡地下储气库。该方案可快速将产气H _{2 S浓度降低至20 mg/m} ³，满足天然气出口标准以及现场HSE（健康、安全和环境）要求。这项研究有助于工程师了解含硫地下储气库H ₂ S的去除，并为将其他多层酸性气田转变为地下封存场提供技术指导。