光纤位移传感器在盐岩地下储气库群模型试验中的应用

Application of fiber bragg grating displacement sensors to geotechnical model test of underground salt rock gas storages

为了研究盐岩地下储气库群运行过程中注采气压变化对洞周围岩变形的影响,设计开发了一种基于光纤布拉格光栅技术的棒式光纤位移传感器,并将其成功应用在盐岩地下储气库群模型试验的位移监测中。试验结果表明,注采气压速率是影响盐岩储气库运营安全的重要因素。采气过程中洞周出现径向收敛位移,该位移随采气速率和时间的增加而增加;注气过程中洞周出现扩张位移,该位移随注气速率和时间的增加而增加。空间上,气压变化对洞腔腰部位移影响最大。为了保证储气库运行安全,应控制注采气速率。针对所研究工程原型,建议储气库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。

In order to investigate the effect of pressure variation on the deformation of surrounding rock, a rod-type fiber-optic displacement sensor based on the fiber Bragg grating(FBG) sensing technology was developed and successfully used for displacement monitoring in the geomechanical model test of salt rock gas storages. The test results show that:the gas injection and extraction rate is an important factor affecting the operation safety of salt rock gas storages. Convergence displacement is monitored during gas injection while expansion is monitored during gas extraction. Both of the displacements increase with time and pressure variation rate. In the space domain, the pressure variation has most obvious effect in the middle part of the caverns. In order to ensure the operation safety of the caverns, the maximum gas extraction rate for the studied caverns should be less than 0.65 MPa/d; the maximum gas injection rate should be less than 0.75 MPa/d.