油田区地下水系统特殊防污性能评价

Evaluation of specific vulnerability of a groundwater system in an oilfield

针对中国典型油田区的水文地质条件、主要石油类污染物性质,对地下水防污性能评价模型DRASTIC进行了改进,建立了油田区地下水系统特殊防污性能评价模型——DORKI。在该模型中选取DRASTIC模型中的地下水埋深、净补给量、包气带介质3个评价因子,增加了土壤有机质含量和有机碳-水分配系数Koc2个评价因子。根据相关资料确定了新增评价因子的评分并通过层次分析法中的九标度法确定了5个评价因子的权重。最后结合某油田区的情况,对DORKI进行实例应用和分析,结果表明,DORKI模型能够较为准确地用于原油组分对油田区地下水的污染风险评价。

Considering hydrogeological conditions and main oil pollutant properties in typical oilfields of China, a new model named DORKI was proposed for specific vulnerability assessment of groundwater in an oilfield, based on the widely used DRASTIC model. In this new model, three evaluation factors including depth to water table, net recharged water amount and media of vadose zone are selected from DRASTIC. Two additional factors are organic content of soil and soil sorption coefficient. The score of the additional factors was established based on relevant data and the weights of the five factors were determined according to nine - demarcation method of the analytic hierarchy process （AHP）. Application of the model to evaluate groundwater situation in an oilfield district shows that the DORKI can reasonably reflect the effect of the additional factors in the evaluation.