Abstract: In this study, an experimental system in which small core devices with different configurations are connected in series was designed, and high-intensity gas injection and production experiments (3 groups, 28 times) were conducted to quantify the per-cycle gas loss (difference between the amounts of injected and produced gas). These experiments reveal that the lost gas fraction is positively correlated with the porosity and permeability of sandstone but negatively related to the number of injection-production cycles. Based on the experimental results, a three-dimensional gas–water two-phase numerical simulation model for high-intensity injection and production of underground gas was established, and a numerical simulation study (10 injection-production cycles) was performed to clarify the macroscopic migration law of gas and water during injection-production. The simulation results show that the gas could cross the gas–water contact (GWC) into the lower water area at approximately 350 m in the injection phase, while the water intrudes into the gas area at approximately 150 m along the high-permeability channel in the production process. Owing to the complex interaction between the gas and water, a large amount of the lost gas that cannot be produced accumulates in the transition zone generated by the reciprocating motion of the gas and water. A certain amount of the lost gas is produced in every cycle; however, the lost gas fraction will decrease with an increasing number of injection and production cycles (a single cycle yields a reduction of more than 10%) and eventually stabilise at approximately 5%. Finally, based on our results, some suggestions were provided for avoiding gas loss while building underground gas storage systems.

中文翻译：

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基于串联小核心装置系统的气体置换实验的地下储气库气体损失定量表征和数值模拟

摘要：本研究设计了不同配置的小型核心装置串联的实验系统，进行了高强度注采气实验（3组，28次），量化了每循环的气损。 （注入气体量和产出气体量之间的差异）。这些实验表明，漏失气分数与砂岩的孔隙度和渗透率呈正相关，但与注采循环次数呈负相关。根据试验结果，建立了地下高强度注采气三维气水两相数值模拟模型，并通过数值模拟研究（10次注采循环），阐明注采过程中气水宏观运移规律。模拟结果表明，在注入阶段，气体可以穿过气水界面（GWC）进入约 350 m 的下部水区，而水沿高渗透通道侵入约 150 m 的气区。生产过程。由于气水之间复杂的相互作用，大量无法生产的损失气积聚在气水往复运动产生的过渡带中。每个循环都会产生一定量的损失气体；然而，随着注入和生产循环次数的增加，损失的气体分数将减少（单个循环产生的减少超过 10%）并最终稳定在大约 5%。最后，根据我们的研究结果，提出了在建设地下储气系统时避免天然气流失的一些建议。