夹层对盐岩储气库注采运行稳定性影响研究

Study on influence of interlayer on stability of injection-production operation of salt rock gas storage

为保证含夹层盐岩储气库长期注采过程的安全稳定,开展夹层几何特征对盐岩储气库注采运行稳定性影响的研究。通过FLAC^(3D)开展数值模拟,研究单一夹层厚度、位置及夹层数量等几何特征对储气库围岩应力、变形的影响规律,并分析盐腔的稳定性和可用性对夹层几何参数的敏感性特征。结果表明:随夹层厚度、数量的增加,盐腔围岩所受压应力增大,收缩变形减小,体积收缩率增大;随夹层到腔体顶板距离减小,盐腔围岩所受压应力先减小后增大,收缩变形增大,体积收缩率减小。各夹层参数的敏感度系数排序为:夹层厚度、夹层数量、夹层位置。该结论可为层状盐岩储气库先导工程的可行性分析与稳定性评价提供参考。

In order to ensure the safety and stability of the salt rock gas storage with interlayer during the long-term injection-production process,the influence of the geometric characteristics of interlayer on the stability of the salt rock gas storage during the injection-production process was conducted.The numerical simulation was carried out by FLAC^(3D),then the influence of geometric characteristics of single interlayer thickness,interlayer position and interlayer number on the surrounding rock stress and deformation of gas storage was studied,and the sensitivity characteristics of the stability and availability of salt cavity to the geometric parameters of interlayer were analyzed.The results showed that with the increase in the thickness and number of interlayer,the compressive stress suffered by the surrounding rock of salt cavity increased,the shrinkage deformation decreased,and the volume shrinkage rate increased.As the distance between the interlayer and the roof of cavity decreased,the compressive stress suffered by the surrounding rock of salt cavity decreased first and then increased,the shrinkage deformation increased,and the volume shrinkage rate decreased.The order of the sensitivity coefficients of each interlayer parameter was the interlayer thickness,the interlayer number and the interlayer position.The above conclusions can provide certain reference value for the feasibility analysis and stability evaluation on the pilot project of the layered salt rock gas storage.