盐岩因其非常低的渗透特性与良好的蠕变行为被公认为能源储备最理想的介质。为有效反映不同采气速率、注气速率、运行低压、运行高压、储库失压、储气压差以及储库间距等极端风险因素对盐岩地下储气库群运营安全稳定的影响,采用满足流变相似条件的盐岩储气库介质模型相似材料,对江苏金坛深部层状盐岩地下储气库群的运营稳定进行三维流变地质模型试验。试验结果表明:(1)洞腔径向位移和径向应变随着注、采气速率的增加而逐渐增大;(2)洞腔随储气内压的减小而不断向洞内收敛变形,随储气内压的增大而不断向洞外扩张变形,当储库采气降压到3 MPa或注气升压到22 MPa时,洞腔出现加速蠕变现象;(3)相邻洞腔位移随着储气压差的增加而增大,当储气压差达到9 MPa时,洞腔出现加速蠕变现象;(4)储库群之间存在明显的相互影响,洞腔位移随着储库间距的减小而增大;(5)当盐腔突然失压时,洞周径向位移和径向应变瞬间突然增大。因此,为保证盐岩地下储气库群的安全运营,建议储气库群的最大采气速率应小于0.65 MPa/d,最大注气速率应小于0.75 MPa/d;储气库群的最低运行气压应大于3 MPa,最高运行气压应小于22 MPa;相邻储气库间的最大储气压差应小于9MPa;储气库之间的间距应大于1.5倍储库最大直径。这些研究成果可为盐岩地下储气库群的运营安全控制与管理提供重要的试验依据。
Salt rock is widely believed as the best medium for underground energy reserve because of its extremely low permeability and good creep properties. In order to reflect the impact of extreme risk factors (including gas extraction velocity, gas injection velocity, low pressure, high pressure, pressure loss, pressure difference, spacing between caverns) on the operational security and stability of salt rock gas storage group, three-dimensional rheological geomechanical model tests on operational stability of Jintan deep laminated salt rock gas storages in Jiangsu Province were conducted with similar material of gas storage medium, which meet the rheological similar conditions. The model results show that: (1) The radial displacement and radial strain increase gradually with the increases of gas injection and extraction speeds. (2) The radial convergence displacements of cavems increase with the decrease of storage pressure and continue to produce expansion deformation with the increase of inner pressure. The accelerating creep phenomenon appears when the storage pressure reduces to 3 MPa or increases to 22 MPa. (3) The displacements of adjacent cavern increase with the increase of pressure difference between two caverns. When the pressure difference reaches 9 MPa, the accelerating creep phenomenon appears. (4) There are significant interactions between storages, and the displacements of caverns increase with the decrease of spacing between two storages. (5) The radial displacement and radial strain abruptly increase instantaneously when the gas storages lose pressure. In conclusion, in order to ensure the operation safety of the gas storages, the following suggestions are proposed. (1) The maximum gas extraction velocity should be less than 0.65 MPa/d; and the maximum gas injection velocity should be less than 0.75 MPa/d. (2) The minimum operating pressure of gas storages should be greater than 3 MPa; and the maximum operating pressure should be less than 22 MPa. (3) The pressur