青海省察尔汗盐湖别勒滩区段晶间卤水数值模拟

Numerical Simulation of Brine in Crystalline Halite in the Bieletan Area of the Charham Salt Lake Region,Qinghai Province

察尔汗盐湖表层盐层晶间卤水资源丰富,特别是在别勒滩区段卤水开采规模较小,具有进一步扩大开采规模的潜力。根据已有的资料和成果,在目前对盐湖水文地质条件认识的基础上,对研究区水文地质条件进行合理概化,建立晶间卤水非稳定流数学模型并进行数值计算,同时对别勒滩区段卤水开采过程进行模拟。结果表明:该模型可以反映盐湖晶间卤水流场的变化,用来对该区段规划的3种不同采卤方案的开采流场进行预报也取得了良好的效果。在模拟计算中将采卤渠概化为有若干个线状排列的抽水井,将一端抽卤泵站的开采量由大到小大体上呈线性比例递减分配到各抽水井上,可以反映采卤渠系对卤水流场的影响。

Abundant brine resources are borne in the near-surface halite aquifer in the Charham Salt Lake region. In the Bieletan area, particularly, brine is not extensively exploited yet, and there is still a great potential for further exploiting brine. Located in the central-eastern part of the Qaidam Basin in Qinghai Province, the Charham Salt Lake is a large-scale mineral deposit of solid-liquid co-existing leopoldite and magnesium salt, the proven solid leopoldite deposits and leopoldite liquid resources are 2.96×10^8 t and 2.44×10^8 t respectively. In this paper, a mathematical model is developed for simulating the unsteady flow of brine in the crystalline halite in the Bieletan area based on available data, research achievements and simplification of the hydrogeologic conditions in the study area. The results show that the developed model can be used to adequately describe the flow field change of the brine aquifer, and the satisfactory results can be obtained to predict the exploitation regimes of three proposed production scenarios for the ditch systems. In the model a ditch can be treated as several wells in a straight line and the drawdown rate of the pumping station at one end of the ditch is assigned to the wells according to a linear decrease effect of the ditch systems in the flow field of the percentage. As a result, the model can be used to describe the brine-bearing aquifer.