盐穴型地下储气库建库评价关键技术及其应用

为了解决层状盐岩盐层展布不均、造腔机理复杂、造腔过程控制难、盐腔运行安全稳定性差、老腔改造利用难度大等技术难题,从盐穴地下储气库盐层利用最大化、提高造腔效率、缩短建库周期、保证腔体安全的设计目标出发,依托江苏金坛盐穴储气库的设计经验与现场实践,全面更新设计理念,提出了选址评价、造腔设计与控制、稳定性评价与库容参数设计、老腔筛选及利用、气库运行及监测等5项关键技术序列,丰富和完善了盐穴储气库建库评价技术体系。上述5项关键技术在金坛盐穴储气库建设中的实际应用效果表明:(1)地质方案实钻符合率高;(2)造腔形态符合设计预期;(3)腔体变形收缩率符合稳定性评价结果预期;(4)老腔改造利用成功;(5)部署监测网络保障了盐穴储气库的运行安全,为长江三角洲地区天然气调峰保供发挥了重要作用。结论认为,该项研究成果指导了盐穴地下储气库的建库方案设计及工程实施,为同类储气库的建设提供了理论支撑与技术保障。

Key technologies for salt-cavern underground gas storage construction and evaluation and their application

Salt-cavern underground gas storage is technically faced with non-uniform distribution of stratified salt rocks, complex solution mining mechanism, difficult control of solution mining process, less operation safety and stability of caverns and difficult reconstruction and utilization of old caverns. In view of these technical difficulties, the design concept was fully updated based on the design experience and field practice of Jintan gas storage in Jiangsu, for purpose of maximizing salt layer utilization ratio, improving solution mining efficiency, shortening construction time and ensuring cavity safety. Based on the updated design concept, five series of key technologies were proposed in site evaluation, cavern design and control, stability assessment and storage capacity parameter design, old cavern screening and utilization, and gas storage operation and monitoring. The following results were obtained from the actual application of these key technologies to the Jintan gas storage. First, the actual drilling coincidence rate of geological program is high. Second, the cavern is morphologically coincident with the design. Third, the cavern deformation retract rate is in line with the stability evaluation result. Fourth, old caverns are successfully reconstructed and utilized. Fifth, the arrangement of the monitoring network ensures the operation safety of salt-cavern underground gas storage and makes an important contribution to the peak shaving and supply guarantee of natural gas in the Yangtze River Delta region. In conclusion, the research results provide guidance for the design and engineering implementation of salt-cavern underground gas storage construction program, as well as a theoretical and technical support for the construction of similar gas storages.