柴达木盆地西部典型地区油田卤水水化学异常及资源评价

Hydrochemical Anomaly and Resources Evaluation of the Oil Field Brines in the Typical Area of Western Qaidam Basin

柴达木盆地自中生代末—新生代以来,由于喜玛拉雅山运动影响,西部形成了众多北西—南东向分布的一系列断裂和褶皱构造单元。这种多断裂带、多褶皱的构造背景,不仅有利于深部水的运移和外围山系风化产物进一步聚集,而且为柴达木盆地盐类资源的储存提供了丰富的空间和场所,富集了广厚的岩盐和深部富钾卤水。在对柴达木盆地西部地表蒸发岩和卤水进行野外实地考察的过程中,在典型的背斜构造区采集和分析了9件油田卤水水样,通过离子含量和一些特征离子比值的分析,发现柴达木盆地西部油田卤水具有高矿化度,高的Na+、Cl-含量和相对更高的Ca2+,低Mg2-、SO42-含量特征;并且盆地西部油田卤水普遍具有较高的K+、Br-、B3+、Sr2+、Li+等离子含量,Br、B3+、Sr2+、Li+等的含量也基本达到了综合利用工业品位和单独开采工业品位,具有潜在的资源意义。

From late Mosozoic to Cenozoic, a series of cracks and folds in the northwest-southeast direction were formed in the western Qaidam Basin due to Himalaya Movements. This kind of tectonic setting which is favor of the migration of deep water and aggregation of the weathering products in peripheral mountain ridges provides plenty of spaces and sites for depositing salt resources in western Qaidam Basin, and it also enriches the wide-thick halite and deep potassium-rich brines. Based upon this, nine brine samples around the typical areas were coUeeted and analyzed for their hydroehemical compositions and characteristic ions＇ ratios. The results showed that the oil field brines in western Qaidam Basin have high salinity, high contents of Na^＋ , Cl^-, higher content of Ca^2 ＋ and low contents of Mg^2 ＋, SO4^2-. Furthermore, there contains high contents of ions generally, such as K^＋ ,Br^- ,B^3＋ ,Sr^2＋ , Li^＋ and so on, whose contents mostly reach the industrial grade for comprehensive and single exploitation. So, great importance should be attached to the useful components of salt lake resources for their exploitation and utilization. Thus it has potential resource significance.