不同处理工艺页岩气钻井岩屑的污染特性

为探究不同处理工艺对页岩气钻井岩屑的处理效果，对重庆市某区域典型页岩气钻井岩屑处理后产生的水基残渣和油基残渣进行采样，系统分析钻井岩屑经不同处理工艺处理前后其特征污染物（重金属、PAHs及石油烃）的残留水平及变化规律.结果表明:热解析与回转窑焚烧结合工艺对油基钻井岩屑中重金属的去除效果较优，热解析与回转窑焚烧结合工艺、单一热解析工艺、热解析与电解结合工艺均可有效去除油基钻井岩屑中的2~4环PAHs以及石油烃中的轻质组分，3种工艺对钻井岩屑中PAHs的去除率分别为72.5%、95.3%、93.0%，对石油烃的去除率分别为90.0%、93.9%、93.2%.采用固液分离+压滤脱水的方式处理水基钻井岩屑，会导致重金属（Cr、Ni、Cu、Zn、Pb、As）和2~4环PAHs在水基残渣中的累积.处理后水基残渣和油基残渣中重金属、PAHs和石油烃含量均未超过GB 5085.6-2007《危险废物鉴别标准毒性物质含量鉴别》标准限值，重金属和PAHs含量均满足GB 36600-2018《土壤环境质量建设用地土壤污染风险管控标准（试行）》要求.研究显示，经热解析为主体的工艺处理后，钻井岩屑中的特征污染物可得到有效去除，具有较好的资源化利用潜力. 

Pollution Characteristics of Typical Field Shale Gas Drilling Cuttings with Different Treatment Processes

In order to explore the effect of different treatment processes on shale gas drilling cuttings, the water-based residues and oil-based residues generated from the treatment of shale gas drilling cuttings in Chongqing were sampled, the residual levels and the change rule of characteristic pollutants (heavy metals, PAHs and petroleum hydrocarbons) of drilling cuttings before and after different treatments processes were systematically analyzed. The results show that the combination process of thermal desorption and rotary kiln incineration has better effect on the removal of heavy metals from oil-based drilling cuttings, the combination of thermal desorption and rotary kiln incineration, single thermal desorption process, thermal desorption and electrolytic combination process can effectively remove 2-4 ring PAHs in oil-based drilling cuttings and light components of petroleum hydrocarbons, the removal rates of PAHs in drilling cuttings by the three processes were 72.5%, 95.3%, and 93.0% respectively, and the removal rates of petroleum hydrocarbons were 90.0%, 93.9%, and 93.2% respectively. Treatment of water-based drilling cuttings with solid-liquid separation and pressure filtration dehydration resulted in the accumulation of heavy metals (Cr, Ni, Cu, Zn, Pb, As) and 2-4 ring PAHs in water-based residues. After treatment, the contens of heavy metals, PAHs and petroleum hydrocarbons in the water-based residues and oil-based residues did not exceed the limits of the Identification Standards for Hazardous Wastes-Identification for Toxic Substance Content (GB 5085.6-2007), heavy metals and PAHs contents met the requirements of Soil Environmental Quality-Risk Control Standard for Soil Contamination of Development Land (GB 36600-2018). The research shows that the characteristic pollutants in the drilling cuttings can be effectively removed by thermal desorption as main treatment process, which has a good potential for resource utilization.