某油田地下水污染特征及其机理分析

Contamination characteristics and mechanism of groundwater in an oilfield in Northeast China

在对某油田石油类污染物分布特征研究的基础上,对其进入地下水的途径进行分析。研究表明,除石油类外,CODMn、Cl-、NO3-N和TDS具异常变化,这些异常变化已成为石油类污染的参考指标。含水层污染程度主要以严重污染和中度污染为主,下段含水层中的石油类污染物的浓度明显高于上段含水层。地下水遭受污染的途径类型分为地表渗透型和优势通道渗漏型,但地表渗透型污染对研究区地下水的威胁性相对来说较小。由构造活动、地下水开采引发的地裂缝形成的优势通道渗漏型污染是地下水污染的主要途径。

The ways in which pollutants enter the ground water were analyzed, based on the known distribution of contaminated ground water in two aquifers in an oilfield The study shows that the anomalies of CODMn, Cl^-, NO3^-, and TDS resulting from petroleum pollutants may be used as the reference indices of petroleum contamination. By and large, two aquifers are either polluted seriously or at medium level. The concentration of petroleum pollutants in the lower aquifer is considerably higher than that in the upper aquifer. The groundwater pollutions are classified into two categories, i. e., by infiltration and by penetration. The groundwater polluted by infiltration is a relatively minor threat to the oilfield compared to the pollution by penetration through geosutures resulting from geological structural movements, which is the major cause of groundwater pollution.