大牛地气田区地下水水质模糊综合评价

自20世纪20年代以来，出现了30多种水质评价的研究方法。但由于水质等级与评价因子间复杂的非线性关系，以及水体污染的模糊性和随机性，地下水水质评价至今没有一个被广泛接受的评价模型。现阶段，地理信息系统（GIS）技术被广泛应用到水质评价中，在此基础上提出了一系列新的水质评价模式和理论。文章以大牛地气田区浅层地下水为研究对象，利用ArcGIS技术，将GIS与改进的模糊综合评价模型结合，建立基于GIS的地下水水质模糊综合评价模型，并应用于研究区地下水水质评价。同时将基于GIS的模糊综合评价结果和传统的内梅罗指数法进行对比，验证新方法在地下水水质评价工作中的合理性与可靠性。结果表明:（1）大牛地气田浅层地下水水质状况总体良好，以Ⅰ类和Ⅲ类水为主，局部地区浅层地下水中氨氮超标，水质较差；（2）模糊综合评价法与GIS的有效结合，实现了地下水水质模糊综合评价的系统化和可视化；（3）相对于内梅罗指数法，基于GIS的地下水水质模糊综合评价模型综合考虑了各评价因子对水质的影响，能够更加客观、合理地评价研究区地下水水质。

Fuzzy comprehensive evaluation of groundwater quality of the Daniudi gas field area

Since the 1920s, there have been more than 30 research methods for water quality assessment worldwide. However, there is no widely accepted evaluation model for groundwater quality evaluation because of the complex nonlinear relationship between water quality grade and evaluation factors, as well as the fuzziness and randomness of water pollution. At present, geographic information system (GIS) technology is widely used in water quality evaluation, and on this basis, a series of new models and theories of water quality evaluation have been put forward. This article takes the Daniudi gas field shallow groundwater as the research object. ArcGIS technology is adopted to integrate GIS with an improved fuzzy comprehensive evaluation model. Therefore, a groundwater quality fuzzy comprehensive evaluation model based on GIS can be created and applied to the groundwater quality evaluation of the research area. In order to verify the rationality and reliability of groundwater quality evaluation, the fuzzy comprehensive evaluation results based on GIS are compared with those with the Nemero index method. The results show that (1) the quality of shallow groundwater in the Daniudi gas field is generally good, and is mainly in class I and class Ⅲ, but the shallow groundwater in some local areas is polluted by nitrogen from domestic sewage, agricultural wastewater and livestock sewage. (2) An effective integration of fuzzy comprehensive evaluation model (FCEM) and GIS combined effectively, and the combination makes FCEM have powerful map display and spatial analysis functions, which make the systematization and visualization of fuzzy comprehensive evaluation of groundwater quality to be realized. (3) Compared with the Nemero index method, the fuzzy comprehensive evaluation model of groundwater quality based on GIS can evaluate the quality level of the collected groundwater with reasonable accuracy.