平顶山盐岩力学特性及废弃盐腔稳定性分析

为了分析废弃盐腔的稳定性,对平顶山盐矿、盐岩、泥质硬石膏岩样进行单轴和三轴压缩试验以及蠕变试验,获得相应的力学特征。对平顶山盐矿某区压裂井、连通井和单井等建库完成后的腔体稳定性进行了数值模拟。结果表明,盐岩层呈现良好的延性变形特征,含泥质硬石膏岩夹层呈现脆性变形的特征。溶腔形状对腔体位移、应力分析以及稳定性等影响较大,从溶腔废弃开始到运行10a,道1井溶腔的最大位移出现在溶腔顶部靠右侧的位置,D1-2单井溶腔的最大位移出现在溶腔围岩边缘腰部位置,而L3-3压裂井溶腔顶部的位移值过大,溶腔顶部和底部已经坍塌,在泥岩夹层处应力集中现象比较明显。道1井溶腔左上角和右上角位置出现塑性区,D1-2单井溶腔顶部位置出现塑性区,在D1-1和D1-2溶腔群的矿柱之间出现了比较大的应力集中。在储气库运行期间,应该提高储气库的最低运行压力并缩短其在低压下的运行时间。

Mechanical properties of Pingdingshan salt rock and stability of abandoned salt cavity

To analyze the stability of abandoned salt cavity,uniaxial and triaxial compression tests and creep test were conducted on the Pingdingshan salt rock and argillaceous anhydrite specimen to obtain the mechanical characteristics.Numerical simulations were carried out on fracturing wells, unicom and single oil wells of Pingdingshan salt mine. Results show that the salt rock reflects the good ductility characteristics,and that the argillaceous anhydrite interlayer reflects brittle deformation characteristics. Cavern shape has a greater impact on the displacement, stress analysis and stability. Starting from the time of cavern being abandoned till its running for 10 years, the maximum displacement of D1 well cavern appears on the right at the top of cavity,the maximum displacement of D1-2 single-well cavern appears at waist location of the surrounding rock,and due to excessive displacement, the top and bottom of L3-3 fracturing wells collapse. Stress concentration phenomenon is more obvious in the interlayer. Plastic zone appears on the upper left and lower right corners of D1 well cavern, and plastic zone also appears at the top of D1-2 single-well cavern.The larger stress concentration appears in the pillars between D1-1 cavern and D1-2 cavern.During the operation of natural gas storage, the minimum operating pressure for gas storage should be raised, and the running time at low pressure should be shortened.