页岩气开发引起的含水层潜在甲烷污染成因机理与识别

Specific to potential methane contamination of drinking aquifer that may arise in the shale gas exploration, select a typical exploration zone, using the "fingerprint" characteristics of different genetic methane and surrounding groundwater geochemistry as the clues, adopt hydrogeology, hydrology geochemistry, isotope hydrology methods to analyze the distribution characteristics of methane、high chain hydrocarbons and tracer indicators in the aquifer, distinguish and quantify different genetic methane in groundwater, identify methane migration channels. Base on these finding, establish a contamination identification index system of the methane in groundwater on shale gas development zone. So that, we can provide a scientific basis for decision making for sustainable, environmentally sound development of the development of Chinese shale gas exploration. Thus, this study has important significance with respect to both theoretical and practical purposes.

针对在页岩气勘查开发中可能出现的含水层甲烷污染问题，选择典型试验开发区，以不同成因的甲烷及周边地下水地球化学"指纹"特征为线索，采用水文地质、水文地球化学、同位素水文学等技术方法，分析含水层中甲烷、高链烃类及示踪指标的分布特征，识别地下水中不同成因类型甲烷和迁移通道，探索地下水中甲烷成因量化标识，揭示页岩气开发引起的含水层潜在甲烷污染成因机理，建立地下水甲烷污染识别指标体系，为我国页岩气勘查开发的可持续、环境友好发展提供科学决策依据。本项目的研究具有重要的理论和实践意义。

本项目选择我国第一口陆相页岩气井“柴页一井”作研究对象，以页岩气和页岩层年老地层水的地球化学特征为线索，采用水文地质学、水文地球化学、同位素水文学等技术方法，结合野外地质调查和室内模拟，探索页岩气有别于含水层中生物成因气的组分和同位素识别指标（直接指标），探寻页岩气伴生物—水力压裂返排液中区别于浅层地下水和油田卤水的识别指标（间接指标），分析上述指标在水力压裂引起的强烈水岩交互作用过程中产生的水化学和同位素动态变化模式，建立了页岩气开发含水层中甲烷污染识别指标体系，设计了页岩气开发区含水层中页岩气污染识别模型。