引用本文:曹洪源,柏明星,杜思宇,张志超,刘业新. 关井阶段CO2作储气库垫层气的动态影响规律[J]. 石油与天然气化工, 2024, 53(3): 37-42.
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关井阶段CO2作储气库垫层气的动态影响规律
曹洪源1,2,柏明星1,2,杜思宇1,2,张志超1,2,刘业新1,2
1.东北石油大学石油工程学院;2.东北石油大学提高采收率教育部重点实验室
摘要:
目的为应对地下储气库中的垫层气损失,采用经济气体CO2作为垫层气,目前,CO2作垫层气在实际应用中存在各种条件限制,且对其在关井阶段的应用研究较少,有必要对在关井阶段CO2作垫层气对天然气储气库的运行影响因素进行研究。 方法利用有限元模拟CO2作储气库垫层气时,研究关井阶段储气库动态参数(注气压力、注气速率和CO2垫层气比例)对混气带的影响规律。 结果注气压力对混气带的影响不大,将其控制在12 MPa左右最为合理,此时混气带占储气面积的比例为23.731 5%;混气带面积占比随注气速率的增大而减小,但是在注气口附近会出现混合区域,导致回采天然气时出现大量的混合气体,所以注气速率控制在0.7×108 m3/d时最为合理,这时混气带面积占比为18.324 6%;CO2作垫层气的比例对天然气-CO2之间的混合影响明显,当CO2垫层气比例为20%时,混气带面积占比为7.236 5%。 结论根据实验结果设计针对混气带的控制措施,当注气压力控制为12 MPa时,注气速率为0.7×108 m3/d,当CO2垫层气比例为20%时,能让储气库的运作更为经济,实验结果可为实际储气库的建设提供参考。 
关键词:  地下储气库  CO2  关井阶段  注气压力  注气速率  垫层气比例  混气带占比 
DOI:10.3969/j.issn.1007-3426.2024.03.007
分类号:
基金项目:国家自然科学基金“枯竭油藏型储气库二氧化碳作垫层气机理及注采动态规律研究”(52174020);国家重点研发计划“二氧化碳提高油藏采收率与地质封存一体化关键技术及应用示范”(2022YFE0206700)
Dynamic influence law of CO2 used as cushion gas in gas storage during shut-in period
CAO Hongyuan1,2, BAI Mingxing1,2, DU Siyu1,2, ZHANG Zhichao1,2, LIU Yexin1,2
1. College of Petroleum Engineering, Northeast Petroleum University, Daqing, Heilongjiang, China;2. Key Laboratory of Enhanced Oil Recovery (Northeast Petroleum University), Ministry of Education, Northeast Petroleum University, Daqing, Heilongjiang, China
Abstract:
ObjectiveIn order to deal with the loss of cushion gas in underground gas storage, CO2, an economical gas, is used as cushion gas. There are various restrictions in applying CO2 as cushion gas, and few studies on its application have been conducted during the shut-in period. Therefore, it is necessary to study the influencing factors of CO2 as cushion gas during the shut-in period in the operation of natural gas storage. Methods The influence of dynamic parameters of the gas reservoir (gas injection pressure, gas injection rate and CO2 cushion gas ratio) on the gas mixing zone is studied when CO2 is used as cushion gas by finite element simulation. ResultsThe results show that the injection pressure has little effect on the mixing zone during the shut-in period. The injection pressure is controlled at about 12 MPa, which is the most reasonable , and the proportion of gas mixing zone in the gas storage area is 23.731 5%. The proportion of the mixing zone decreases with the increase in gas injection rate, but the mixing zone near the gas injection port leads to a large amount of mixed gas when recovering natural gas. Therefore, it is reasonable to control the gas injection rate at 70×106 m3/d, and the proportion of mixing zone is 18.324 6%. CO2 cushion gas ratio has an obvious effect on the mixing between natural gas and CO2. When the CO2 cushion gas ratio is 20%, the proportion of the gas mixing zone is 7.236 5%. ConclusionsAccording to the experimental results, the control measures for the gas mixing zone are designed. When the injection pressure is controlled to 12 MPa, the gas injection rate is 70×106 m3/d, and the CO2 cushion gas ratio is 20%, the operation of the gas storage can be more efficient, and the reference can be provided for the actual construction of the gas storage.
Key words:  underground gas storage  CO2  shut-in period  gas injection pressure  gas injection rate  cushion gas ratio  proportion of gas mixing zone