煤层气开发环境污染特征及防治对策研究

煤层气开发是一个时短、线长、面广的工程活动,具有单井产气量低、井网密度大、降压排水等独特特征,对生态环境有一定的影响。文中分析了煤层气开发过程中钻井废液、排采水等污染物的性质,结果表明,钻井废液中COD浓度较高,为1 985.5 mg/L,As、Cr、Cu、Zn、Mn、Fe、Pb等重金属含量均在污水综合排放二级标准之内;排采水中含有较高的COD、重金属、盐浓度,经自然沉降后,COD、重金属浓度有所降低,而盐浓度变化不大;考察了煤层气开发对土壤环境质量的影响,发现钻井过程对土壤盐渍化没有影响,但土壤中As含量有所增加。在此基础上,提出钻井废液、排采水及污染土壤的具体防治对策,为煤层气开发污染治理提供理论依据与技术支持。

Environmental Pollution Characteristics and Control Measures of Coal-bed Methane Exploration and Development

The process of developing coal-bed methane which is short,with the unique characteristics of low well gas production,high well density and much water discharged by decreasing the pressure has certain impacts on ecological environment.The paper analyzed the chemical properties of waste drilling fluid and coal-bed methane discharge water,the results showed that COD concentration of waste drilling fluid was 1 985.5 mg/L;COD,heavy metal and salt concentrations of coal-bed methane discharge waters were high,COD and heavy metal concentrations were decreased after the natural sedimentation,while salt concentration had no change.The change in soil quality was further determined,and soil As contents was increased by exploring coal-bed methane.Pollution control measures were proposed,which would provide theoretical basis and technical support for the pollution control in the process of developing coal-bed methane.