呼图壁大型储气库扩容提采关键技术研究

Research on Key Technologies for Dilatancy and Recovery Improving in Hutubi Large-scale Gas Storage

地下储气库作为季节调峰及应急采气的手段,具有单井产量高、快速强注强采、地层应力交替变化等特点。呼图壁储气库经过多个周期注采运行,表现出注采井利用率低、井网调峰能力不足、地面装置运行效率偏低等突出问题,且随着气库逐步达容,地层压力已接近设计上限,区域断裂、盖层、井筒均存在漏失风险。因此开展周期库容诊断评价、调峰能力评价及水侵区动用技术研究,提高储气库井网利用率和调峰能力,形成集"库容诊断、井筒完整性评价和微地震监测"为一体的气库完整性评价技术,评价落实气库动态密封性,保障气库"存得住";优化地面配套增压及集输处理工艺,保证注气压缩机运行效率及外输气产品质量,确保合格气"送得走"。最终形成了集注采地质、井筒工艺和地面集输为一体的储气库扩容提采关键技术体系,实现了呼图壁储气库多周期的安全、平稳、高效运行,为气库预定调峰能力的发挥提供了技术支持。

As a means of seasonal peaking and emergency gas recovery, underground gas storage has the characteristics of high single well production,rapid and intensive injection-production,and alternating formation stress.After several cycles of injection and production,Hutubi gas storage still shows major problems such as low utilization rate of injection and production wells,insufficient peaking ability of well pattern and low operating efficiency of ground equipment.Moreover,as the gas storage gradually reaches its capacity,the formation pressure is close to the designed upper limit,and there is a risk of leakage in the regional fracture,cap rock and wellbore.Storage capacity was judged and evaluated in cycle.Peaking capability was evaluated,too.Producing technology for water intrusion zone was studied.Thereby the utilization rate and peaking capacity of the well pattern of the gas storage was improved.A gas storage integrity evaluation technology that integrates "storage capacity diagnosis,wellbore integrity evaluation and microseismic monitoring" was formed,thus dynamic sealing of the gas storage was evaluated and the gas may store without leakage.The ground supporting pressurization and gathering and transportation process was optimized to ensure the operating efficiency of the gas injection compressor and the quality of the external gas transmission product,thus the qualified gas may be "sent away".A key technical system of dilatancy and recovery improving of gas storage was proposed,which integrates geology of injection and production,wellbore technology and surface gathering and transportation.Safe,stable and efficient running with multi-period has been realized for the Hutubi gas storage,and the technical support has been provided for the development of the gas storage peaking capability.