层状盐岩小井间距双井水溶造腔流场相似模拟研究

Flow Field Physical Experiment of Twin-well of Small Spacing Vast Cavity and Its Numerical Calculation

为解决层状盐岩单井水溶造腔过程中建槽周期长,提管工艺复杂等问题,开展层状盐岩小井间距双井水溶造腔技术研究。拟采用选定物理法建立相似试验平台,探讨小井间距双井水溶造腔流场及浓度场特征,揭示双井水溶溶腔腔体扩展与流场的联系。结果表明:双井水溶造腔过程中腔体流场可以划分为4个区域:边界溶蚀区、浮羽流区、对流扩散区和底部饱和区,各个区域相互影响。浮羽流区是驱动流体运移的关键区域,根据浮羽流区流场特征建立相应的流场模型;根据宏观流动特征,对流扩散区分为强扩散区和弱扩散区;边界溶蚀区对双井水溶溶腔腔体扩展有显著影响;饱和区示踪特征不明显但浓度分层明显。通过对比分析双井造腔和单井造腔模型试验结果,发现双井水溶造腔工艺有利于盐穴建槽期,研究为小井间距双井水溶造腔技术的应用提供一定的理论基础,对盐穴储气库的优化建造具有重要意义。

In order to solve the issues during the construction of the water-soluble single well bedded rock salt cavern,including the long trough period,the complex stripping tube process etc.,the technology of the water-soluble cavity for double well with horizontal well spacing was studied.A similar experimental platform was proposed to establish a physical method.The characteristics of the flow field and concentration field of the water - soluble cavity in the well spacing were discussed,which revealed the relationship between the cavity expansion and the flow field in double well water soluble cavity.The results showed that the cavity flow field was divided into four regions：the boundary eroded area,the floating plume area,the convective diffusion area, and the bottom saturated zone.And different regions influenced each other.The floating plume area was the key area to drive the flow field of the cavity,and the corresponding flow field model was established according to the flow field characteristics of the plume.According to the macroscopic flow characteristics,the convective diffusion was divided into strong diffusion region and weak diffu- sion region;the boundary dissolution region had a significant effect on the cavity expansion of the double well water soluble cavity.The tracer characteristics of the saturated zone were not obvious while the concentration stratification shows the opposite.By comparing and analyzing the results of double well cavity and single well cavity model,it was found that the process of double well water soluble cavity could be beneficial to the construction of salt hole.The study provides a theoretical basis for the application of water well in the well spacing,which is of great signific- ance to optimize the construction of salt cavern gas storage.