Abstract:Engineering thermal analysis for natural gas storage in deep salt formation is one of the bases of stability evaluation and running control. The presented analysis,in which the actual shape of the cavern and the thermal field are considered,is based on the variable mass system thermodynamics and is performed by 3D fast Lagarangian analysis of continuum(FLAC3D). The pressure on the top of the wellbore and that of the cavern increase linearly during injection phase,and decrease linearly during production phase. The temperature changes of the cavern and its wall obey parabola law during injection phase;during production phase,the temperature decreases firstly,then the decrease tendency slows down,and the temperature even increases somewhat at last. The temperature of the wellbore bottom and top changes as that of the cavern does during the whole cycle,but the variation magnitude of the former is smaller than the later one. Though the influence range of the temperature field during the gas injection and production is only 7–15 m around the cavern,the temperature gradient is greater comparatively. This high gradient of temperature may affect the stability of the cavern.