察尔汗盐湖霍布逊区段资源开采过程中储卤层系统变化特征研究

柴达木盆地察尔汗盐湖赋存储量可观的低品位固体钾盐矿, 其主要的开发方式为液化开采。本文对比分析了霍布逊区段盐湖资源大规模开采前(2004年)和开采后(2011年和2019年)典型钻孔岩芯孔隙度、固体钾矿含量、卤水组分变化特征, 评价了钾盐液化开采效率。结果表明: 由于大规模采卤使得大量高矿化度卤水被带出, 而低矿化度水体补给储卤层孔隙并溶解盐层中盐类矿物, 使得储卤层孔隙率有逐渐增大趋势; 卤水中主要组分KCl和NaCl浓度均出现降低现象, 而MgCl2则出现增加趋势, 这主要与补水工程及补给水体中兑卤有关。在这期间, 卤水矿中KCl品位下降幅度要小于固体矿床KCl品位下降幅度, 说明卤水溶解了石盐层中大量固体低品位钾矿, 提升了其KCl品位。本次研究对于优化霍布逊区段固体钾盐液化开采方案具有重要的指导意义。

Comparative Analysis on the Characteristic Changes of the Brine Reservoir System before and after Exploration of the Qarhan Salt Lake (Huobuxun Area)

Qarhan Salt Lake in Qaidam Basin has a considerable amount of low-grade solid potassium salt ore; developed mainly through water-replenishing dissolved liquefaction mining. This paper compares and analyzes the characteristics of typical drilling core porosity, solid potassium ore content, and halogen composition change before (2004) and after (2011 and 2019) large-scale exploitation of salt lake resources in Hobson District, and the efficiency of potassium salt liquefaction mining is evaluated. The results show that a large number of high-mineralized brines are brought out due to large-scale brine mining, while the low mineralization water recharge reservoir pores dissolve salt minerals in the salt layer, gradually increasing the porosity of the reservoir. During this period, the KCl grade drop in brine ore was less than the decrease in the KCl grade of solid deposit. This showed that the brine dissolved a large number of solid low-grade potassium ore in the stone salt layer, raising its KCl grade. This paper is of great significance for the optimization of solid potassium salt liquefaction mining scheme in the Qaidam Basin.