Open Access

ARTICLE

Simulation on H₂S Migration and Elutriation during Cyclic Operationof Underground Sour Gas Storage

Siji Chen¹, Gang Chen², Wei Wang², Han Liu¹, Mukun Ouyang¹, Wanhong Zhang¹, Lianghua Zhang¹, Wei Tang¹, Shilai Hu^2,*

1 Chongqing Gas District, PetroChina Southwest Oil & Gasfield Company, Chongqing, 400021, China
2 School of Petroleum Engineering, Chongqing University of Science and Technology, Chongqing, 401331, China

* Corresponding Author: Shilai Hu. Email:

(This article belongs to the Special Issue: Integrated Geology-Engineering Simulation and Optimizationfor Unconventional Oil and Gas Reservoirs)

Energy Engineering 2025, 122(7), 2819-2843. https://doi.org/10.32604/ee.2025.065481

Received 14 March 2025; Accepted 29 April 2025; Issue published 27 June 2025

Abstract

The construction and operation of sulfur-containing gas storage are often more difficult than a non-sulfur storage facility due to the need to prevent environmental contamination from H₂S leaks, as well as the corrosive effects of H₂S on production facilities. Rapid elutriation of H₂S from the reservoir during the construction of the gas storage is an effective way to avoid these problems. However, the existing H₂S elutriation method has low efficiency and high economic cost, which limits the development of reconstructed gas storage of sulfur-containing gas reservoirs. To improve the efficiency of H₂S elutriation in sulfur-containing gas reservoirs and enhance the economic benefits, a numerical simulation model of multiphase flow components was established to study the migration law of H₂S in the multi-cycle operation of gas storage. Based on the H₂S migrate law, the displacement H₂S elutriation method was developed, and the elutriation mechanism and elutriation efficiency of the two methods were compared and analyzed. In addition, the main controlling factors affecting the H₂S elutriation efficiency were investigated, and the H₂S elutriation scheme of H gas storage was optimized. The results indicate that H₂S migrates between near-well and far-well regions under pressure differentials. The traditional H₂S elutriation method relies on concentration gradient diffusion, whereas the displacement elutriation approach leverages pressure differentials with higher H₂S elutriation efficiency. For the displacement elutriation method, higher reservoir permeability enhances the peak-shaving capacity of the gas storage but has a minor impact on H₂S elutriation when the formation permeability is between 30 and 100 mD. The elutriation efficiency is significantly higher when wells are drilled in the high structural parts of the reservoir compared to the low structural parts. Longer displacement elutriation time within a cycle improves H₂S elutriation efficiency but reduces the working gas volume of the storage. Therefore, the optimal displacement time for H gas storage is 60 days. An optimized H₂S elutriation scheme enabled the working gas to meet the national first-class natural gas standard within 10 cycles. This study elucidates H₂S migration patterns, H₂S elutriation mechanisms, and key influence factors on H₂S elutriation efficiency, offering valuable technical insights for sour gas storage operations.

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