微波消解-原子吸收光谱法测定岩芯中的8种金属元素

Determination of Metal Elements in Drill Cores by Microwave Digestion-Atomic Absorption Spectrometry

岩芯分析是油气田开采前期必须开展的必要研究工作。岩芯样品常见金属元素钾(12.30 mg/g)、钠(15.04 mg/g)、铝(28.83 mg/g)、铁(11.13 mg/g)含量较高,且含有大量有机物,文章首次提出以微波消解方式,用浓硝酸和过氧化氢分解有机物,盐酸和氢氟酸处理二氧化硅等无机物,分解稠油油藏岩芯样品效果明显,原子吸收光谱法测定样品中钾、钠、钙、镁、铝、铁、锰、钡8种金属元素的含量。分析结果表明,方法线性相关系数良好(相关系数为0.9949～0.9998),回收率在92.2%～101.6%。建立的微波消解技术无样品损失,操作简单,消解过程节省试剂,减少了环境污染,测定方法准确、可靠,检出限低。

Drill core analysis is a necessary preliminary study to explore oil and gas field.This kind of drill core always contains high contents of K（12.30 mg/g）,Na（15.04 mg/g）,Al（28.83 mg/g） and Fe（11.13 mg/g） with large amount of organic matter.This is the first time that the method of decomposing organic matter in the drill core by microwave digestion with concentrated HNO3 and H2O2,and dissolving the silicates by HCl and HF acids has been used.The elements of K,Na,Ca,Mg,Al,Fe,Mn and Ba were measured by using atomic absorption spectrometry.The linear correlations of standard curves were obtained（r=0.9949-0.9998） and recovery factors were between 92.2%-101.6%.This method of microwave digestion has advantages of no sample loss,simple operation,less usage of reagents and is environmentally friendly,as well as being accurate,reliable and having a low detection limit.