重庆市页岩气开采流域地表水资源安全的综合评价

页岩气开采消耗大量水和产生组成复杂的高盐返排-产出水,对开采区水资源的安全构成很大风险。论文识别了决定山区页岩气开采的水资源可利用性和返排-产出水对地表水环境胁迫的关键因素,构建了流域地表水资源安全评价方法,以亚流域为单元,完成了2010—2020年重庆地区页岩气开采前后、不同开采强度下地表水资源安全的评价。2010—2020年重庆市页岩气开采的取水对区域水资源的总体压力小,对渝西局部缺水地区的短时影响较大;页岩气开采的返排-产出水对重庆中西部都市区及周边的污染负荷高值区,东北部秦巴山城口、巫溪水环境高敏感区的潜在污染风险大;重庆市页岩气开采的水资源安全水平以好、中等为主,占重庆总面积的2/3,其总体格局呈渝东南>渝东北>渝西。随着经济、社会发展及页岩气的规模化开采,局部水资源安全等级有下降的风险,研究成果可为区域页岩气开采水资源配置和水环境保护提供决策支持。

Comprehensive Assessment of Surface Water Resource Security in Basin with Shale Gas Extraction in Chongqing,China

High water consumption and high saline backflow-production water containing complex organics caused by shale gas extraction will bring potential risks to water resource. In this study, the key factors which describe the availability of water for shale gas extraction in a mountainous area and the impact of backflow-production water on the surface water environment are identified. Furthermore, a method is developed to assess the security of surface water resource in a basin. The spatio-temporal analysis of water resource security in Chongqing is carried out, and the water resource security before and after shale gas extraction during 2010-2020 at different extraction intensity is assessed. The results show that the water consumption of shale gas extraction has a little impact on the regional water resource in total during 2010-2020, but it has more significant impact in the temporary water-deficient areas in western Chongqing. The discharge of backflow-production water of the shale gas extraction poses a potential risk of pollution in the urban areas of Midwest Chongqing and nearby areas with high pollutant loadings, and areas with high sensitive surface water environment such as Chengkou and Wuxi. The levels of water resource security in Chongqing are basically medium security and good security, whose areas account for the two thirds of the total area of Chongqing. The pattern of water resource security in Chongqing is as the following: the southeast is safer than the northeast, and the northeast is safer than the west. With the development of economy and society and the expansion of shale gas extraction, the level of water resource security in some sub-areas is at a risk of declining. The results provide the support to the decision-making in water resource allocation and water environmental protection for the shale gas extraction in Chongqing.