地下盐岩溶腔储库单井水平溶解建造流体运移研究

Study on Fluid Migration of SWRH Leaching Method of Salt Cavern Underground Storage

为提高水平盐穴储库单井后退式溶腔建腔速率,通过相似模型试验与数值计算开展建腔期注水方向对腔内流体运移规律影响研究。数值模拟结果表明:注入淡水接触腔内卤水后浓度会迅速升高,当浓度达到23%左右变为缓慢升高;上下同时入射有利于快速溶腔,垂直向下入射有利于建造更大腔体。相似模型试验流体运移规律与数值模拟基本一致,证明了数值模型的正确性。试验发现:腔内流体主要分为羽流区、边界溶解区、对流扩散区和底部饱和区4个区域;改变注水方向使羽流区流体浓度和流速改变,进而影响边界溶解区高度,与水平入射相比,垂直向上入射、上下型入射、四周型入射和垂直向下入射高度增加了22.2%、26.9%、51.1%、135.6%;改变注水方向使淡水初始向下流速改变,进而改变底部饱和区高度,与水平入射相比,垂上、四周、上下、垂下入射高度降低0%、12.9%、29.9%、70.1%。

In order to improve the cavity construction rate of SWRH(single-well retreating horizontal) leaching method on Salt Cavern Underground Storage,the influence of water injection direction on fluid migration in the cavity was studied during cavern constructional period through similar model test and numerical calculation.Simulation results show:The concentration of the injected fresh water increases rapidly after contacting the brine in the cavity,when the concentration increases to about 23%,it becomes a slow increase;the upward and downward incidence is beneficial to the construction of rapid cavity,and the vertical downward incidence is beneficial to the construction of larger cavity.The fluid migration law of similar model test is basically consistent with that of numerical simulation,which proves the correctness of the numerical model.Tests found:the fluid in the cavity can be divided into four regions:the plume region,the boundary solution region,the convective diffusion region and the bottom saturation region;Replacing the water injection direction changes the fluid concentration and velocity in the plume region,which in turn affects the height of the boundary solution region.Compared with the horizontal incidence,the vertical upward incidence,the upward and downward incidence,the four directions incidence and the vertical downward incidence boundary dissolution zones increase by 22.2%,26.9%,51.1%,135.6%.Replacing the water injection direction changes the initial downward flow rate of fresh water,which in turn changes the height of the bottom saturation region Compared with the horizontal incidence,the vertical upward incidence,the upward and downward incidence,the four directions incidence and the vertical downward incidence heights are reduced by 0%,12.9%,29.9%,70.1%.