微生物驱油产出液中有机酸的监测及对提高采收率的作用研究

Monitoring of the organic acid in the produced liquid in microbial flooding process and effect of the organic acid on enhancing oil recovery factor

通过对样品前处理工艺优化,建立了气相色谱-质谱联用(GC-MS)技术对微生物驱油现场产出液中有机酸的快速定性定量分析方法.该方法灵敏度高,对有机酸定量检测限可以达到0.01mg/L.采用该方法对宝力格油田微生物驱过程中有机酸的浓度变化进行了跟踪监测.结果表明,从注水井注入的葡萄糖在地层中很快被微生物分解为有机酸,主要以短链脂肪酸为主,其中乙酸浓度最高,在营养液注入6周时质量浓度达到419 mg/L.随着营养液注入停止,产出液中有机酸浓度也开始下降.通过不同浓度的乙酸对改变岩心渗透率及提高原油采收率实验表明,微驱过程中产生的有机酸对岩心的溶蚀及提高采收率的作用非常有限.

A rapid qualitative and quantitative analysis method for the organic acid in the produced fluid with gas chromatography——mass spectrometry(GC-MS) is established by optimizing the pre-treatment process of the produced fluid samples.The method is of high sensitivity,and the quantitative detection limit of organic acids can reach to 0.01mg/L.the concentration of organic acid in the produced fluid of Baolige Oilfield was monitored on-site during microbial flooding by this method.The results show that the injected glucose is quickly decomposed to short chain fatty acids by microbial.Of these acids,the concentration of acetic acid is the highest,and it reaches to 419 mg/L after nutrient solution of microbial is injected 6 weeks.After stopping the injection of the nutrient solution,the concentration of the organic acids in the produced fluid begins reducing.The experimental results of acetic acid with different concentration show that,the dissolution effect of the acetic acid produced during microbial flooding on cores and its effect on enhancing recovery factor are very limited.