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井喷压力失控是盐岩储气库运营的极端情况。根据一维绝热管流理论解析得到井喷情形下储库卸压规律。在此基础上结合金坛盐矿工程地质条件,模拟对比分析了不同初始内压失控工况下盐岩储库应力状态、变形收敛特征和损伤破坏规律。结果表明,溶腔硬夹层总是先于盐岩体而屈服形成明显的屈服带,失控卸压阶段塑性区逐渐扩展布满整个腔体并向径向延伸6～8 m;运营压力范围内初始内压越低,储库卸压收敛越大,7 MPa下储库体积损失达5.02%;卸压阶段溶腔内壁围岩应变速率跃升至10-2 s-1数量级,属于准静态范畴。研究认为,井喷失控状态下失控初始内压是维持储库腔体稳定性的关键因素,在极端灾害环境中应确保盐岩储库处于较高的运营压力之下。
Out of control of blowout pressure is the extreme condition of salt rock gas storage operation. According to the theory of one-dimensional adiabatic pipe flow, the depressurization law of reservoir under well blowout is obtained. Based on this, combined with the geological conditions of Jintan Salt Mine, the stress state, deformation and convergence characteristics and damage rules of salt rock reservoirs under different initial conditions of internal pressure loss are simulated and compared. The results show that the hard interlayer in the cavity always yield prior to the salt rock mass and yield a clear yield zone. The plastic zone in the uncontrolled pressure relief phase gradually expands to cover the entire cavity and extends radially to 6 ~ 8 m. In the initial operating pressure range, The lower the internal pressure, the larger the depressurization convergence of the reservoir, and the volume loss of the reservoir reached 5.02% under 7 MPa. The strain rate of the surrounding rock in the pressure chamber during the depressurization stage jumped to the order of 10-2 s-1 and belongs to the quasi-static category. The study shows that uncontrolled initial internal pressure in well blowout uncontrolled state is the key factor to maintain the stability of reservoir chamber. In extreme disaster environment, it is necessary to ensure that salt rock reservoir is under higher operating pressure.