页岩气开采区地下水脆弱性评价模型

为了更准确评价页岩气开采过程中水力压裂和废水回注对地下水的影响,需要采用不同指标体系的模型对地下水脆弱性进行评价。通过分析页岩气开采过程中污染物的潜在运移途径,在DRASTIC模型的基础上分别建立了开采井区地下水脆弱性评价模型DIRTEV和回注井区地下水脆弱性评价模型DIRWOCT。根据相关资料对模型中各评价因子进行了分级及评分,运用模糊综合矩阵法确定了各因子权重,并利用单参数法对评价结果进行了敏感性分析。对四川某页岩气采区的评价结果表明,所建模型能较好地应用于页岩气开采区地下水脆弱性评价。

Assessment model of groundwater vulnerability in shale gas exploitation area

In order to assess more precisely the effects of hydraulic fracturing and wastewater reinjection on groundwater during the shale gas exploitation, the model with different evaluating index is required to evaluate the groundwater vulnerability. Based on the DRASTIC model, the assessment model of groundwater vulnerability in mining area, DIRTEV, and groundwater vulnerability assessment model in reinjection well area, DIRWOCT, were established, respectively, by analyzing the potential transport pathways of pollutants during shale gas exploitation. The evaluation factors in the model were graded and graded according to the relevant information. The weight of each factor is determined by fuzzy comprehensive matrix method, and the sensitivity analysis of the evaluation results is carried out by using the single parameter method. The evaluation results of a shale gas mining area in Sichuan show that the established models can be applied to the groundwater vulnerability evaluation in shale gas exploitation areas.