摘要
由于含煤地层不同程度地富集氟、砷、镉、铬、汞和锑等多种有毒有害元素,煤层气开发过程中的大量产出水会对表生生态环境构成严重威胁.对贵州西部某煤层气开发区块产出水的水化学特征进行了系统研究,结果表明:与地下水质量标准(GB/T 14848-2017)Ⅲ类水质相比,研究区煤层气产出水中Ba和Hg严重超标,平均含量分别达到10 621.6μg/L和16.5μg/L.较强的硫酸盐还原作用导致地层水中硫酸盐被耗尽,含Ba碳酸盐矿物的溶解进而造成产出水表现出明显的Ba异常.Hg主要来源于含煤地层中的硫化物,而硫化物和碳酸盐矿物的溶解是Cr、Mo、Cd和Sb四种元素的主要来源;较高浓度的Mo与离子交换反应有关,并可能以铁锰氧化物和氢氧化物、硫代钼酸盐和钼的金属硫化物等形式存在;Al的氢氧化物吸附态是产出水中Cr、Mo、Mn、Cd、Sb、Cd、Cu、Pb和Ba的主要赋存形态;Ni主要来源于煤有机质的矿化.水质评价结果显示,研究区煤层气产出水的污染状况极为严重;其中,Hg在SH9煤层气井中超标27倍,而Ba在SH8煤层气井中超标23倍.
Coal seams are often enriched in various toxic and harmful elements such as F,As,Cd,Cr,Ni,Pb,Hg and Sb,so the ecosystem might be faced with serious environmental threats when the co-produced water is brought to the surface in the production of coalbed methane(CBM).In this paper,we present a systematic water chemistry study of co-produced water from Songhe coalbed methane development block in western Guizhou Province.The results show that,compared to ClassⅢof Groundwater Quality Standard(GB/T 14848-2017),Ba and Hg in co-produced water in the study area exceeded the standard seriously,and the average concentrations were 10 621.6μg/L and 16.5μg/L,respectively.The Ba anomaly in co-produced water was attributed to the dissolution of Ba-bearing carbonates and the depletion of sulfate induced by sulfate reduction,and Hg was from sulfide minerals.The sources for Cr,Mo,Cd and Sb were sulfides and carbonates in coal seams.The high content of Mo is associated with ion exchange reactions under high salinity,and molybdate and metallic sulfides are the main forms for Mo.Under weak alkaline conditions,the hydroxide adsorption state of Al is the main occurrence form of Cr,Mo,Mn,Cd,Sb,Cd,Cu,Pb and Ba in the co-produced water.The sources of Ni were obviously different from those of other elements,and it most likely came from the mineralization of coal organic matters.The results of water quality evaluation showed that the pollution of the water coproduced from coalbed methane wells in the study area is very serious,which is mainly due to the serious overstandard of Hg and Ba.In SH9,mercury is 27 times the legal limits and that is 23 times for barium in SH8.
作者
李清光
吴攀
顾尚义
刘沛
胡海洋
高为
龚朝兵
常溪溪
Li Qingguang;Wu Pan;Gu Shangyi;Liu Pei;Hu Haiyang;Gao Wei;Gong Chaobing;Chang Xixi(Key Lab of Karst Environment and Geohazard of Ministry of Land and Resources,College of Resource and Environmental Engineering,Guizhou University,Guiyang 550025,China;Guizhou Research Center of Shale Gas and CBM Engineering Technology,Guiyang 550081,China;Guizhou Bureau of Coal Geology,Guiyang 550008,China)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2019年第9期2862-2873,共12页
Earth Science
基金
国家自然科学基金项目(Nos.U1612442-6-7,41867050,41772122)
贵州省公益性基础性地质工作项目(黔国土资地环函[2014]23号)
贵州省基础研究计划(黔科合基础[2019]1096)
贵州大学人才培育项目(黔科合平台人才[2017]5788)
贵州大学人才引进项目(贵大人基合字[2017]73号)
贵州省一流学科建设项目(No.GNYL[2017]007)
贵州省人才基地项目(No.RCJD2018-21)
关键词
煤层气产出水
有毒有害元素
钡异常
来源
水质评价
水文地质
coalbed methane co-produced water
toxic and harmful element
enrichment of barium
source
water quality assessment
hydrogeology