页岩气开发中压裂返排液的水质污染特征研究  

On the organic pollutants and molecular weight distribution in the HFFW of shale gas in Sichuan

作　　者：王兵[1,2] 王佩洁 祝伟 熊明洋[1] WANG Bing;WANG Pei-jie;ZHU Wei;XIONG Ming-yang(School of Chemistry and Chemical Engineering,Southwest Petroleum University,Chengdu 610500,China;Environmental Protection Oil and Gas Fields in Sichuan Province Key Laborato-ry of Pollution Control and Environmental Safety,Chengdu 610500,China;Safety and Environmental Protection Depart­ment,PetroChina Tarim Oilfield Company,Korla 841000,Xin­jiang,China)

机构地区：[1]西南石油大学化学化工学院,成都610500 [2]四川省环境保护油气田污染防治与环境安全重点实验室,成都610500 [3]中国石油塔里木油田公司质量安全环保处,新疆库尔勒841000

出　　处：《安全与环境学报》2020年第1期231-237,共7页Journal of Safety and Environment

基　　金：国家科技重大专项(2016ZX05062)。

摘　　要：页岩气压裂返排液成分复杂,为了解页岩气开采过程中压裂返排液的污染情况,对四川某页岩气典型井场不同时期的压裂返排液污染物组成进行了分析,采用超滤膜法测定溶解性有机物(DOM)相对分子质量分布特性,通过建立水质矩阵开展污染特性评价,并进行了综合生态毒性研究。结果表明,该区域不同时期压裂返排液中污染物特征相似,主要污染因子为总有机碳(TOC)和氯离子,并且生物毒性高、可生化性差。研究结果可为该区域压裂返排液处理技术的选择提供参考。The given paper takes it as its chief goal to make a detailed analysis of the composition of the hydraulic fracturing back-flow water(HFFW)of the shale gas in the various mining periods in Sichuan so as to clarify the DOM molecular weight distribution features.To achieve the purpose,we have conducted a comprehensive ecotoxicity experiment and the pollution feature evaluation.The results of our experiment and pollution feature evaluation reveal that:The composition of the back-flow water in different periods of shale gas turn out to be similar,though somewhat different in pollution load.More specifically speaking,the concentration of TDS tends to increase with time,whereas the Cl-concentration rate tends to be regular in the early-return of the polluted water(21500 mg/L)<mid-return(24380 mg/L)<late-return(27800 mg/L).On the other hand,the concentration rate of the total suspended solids in the early-return of the polluted water should be equal to 182 mg/L,whereas the late-return fluid is merely 43 mg/L.As to the NH3-N concentration rate,it proves higher than 85 mg/L in the middle and late-return.As to the composition of the organic pollutants,they are mainly made of alkanes and dibutyl phthalate,also similar to that of the different time-length periods.The molecular weight of the DOM is mainly clustered in the interval level less than 1 k Da.The ratio of the DOM in the HFFW of less than 1 kDa in the early,middle and late return fluids accounts respectively for 92.7%,88.2%and 91.4%.Based on the water quality matrix and weighing factor analysis,the main pollution factors that mainly influence the HFFW are TOC,Cl-,and so on.What is more,the organic pollutants and chloride ions should be taken as the primary treating targets for the flow-back water in this area.The said flow-back water from the different periods have actually been poisoned by the bright luminescent bacilli,with its order of ecotoxicity to algae being in a descending order of CN-M(poisoning)>CN-L(poisoning)>CN-E(microtoxic).Among the said poisonous com

关 键 词：环境工程学 页岩气 压裂返排液 污染特征 综合毒性 

分 类 号：X741[环境科学与工程—环境工程]