天然气开采钻井固体废物处理处置及资源化技术的应用现状与展望

Application status and prospects of solid waste disposal and resource utilization technology in natural gas extraction drilling

  • 摘要: 天然气开采过程产生大量的钻井固体废物,含有石油烃、无机盐及难降解有机物等有毒有害物质。水基钻井固体废物的pH一般为9~10,超出GB 18599—2001《一般工业固体废物贮存、处置场污染控制标准》中Ⅰ类场贮存及回填的技术要求;石油烃浓度为4 690~15 500 mg/kg,超出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)》中第二类用地土壤污染风险筛选值;四川、重庆、新疆等部分气田由于地形复杂使用油基钻井液,可能会导致重金属、多环芳烃(PAHs)及石油烃浓度超标。钻井固体废物主要组分为SiO2、CaO、Al2O3,三者占比可达72%,包含了制备建筑材料必要的化学组分。在钻井固体废物的污染特性和化学组分解析基础上,系统地总结和分析了国内外钻井固体废物的处理处置技术,包括固化稳定化、生物降解、化学淋洗、井下回注、源头减量化技术等,阐述了各技术特点、处理效果以及资源化利用(如制砖、井场铺路、改良剂等)的研究状况,提出采用多种处理处置技术可有效降低钻井固体废物中的污染物浓度,而多元化的资源化利用途径可提高固体废物的利用率,具有较好的发展前景。建议从源头上对钻井固体废物进行分类分质处理,过程中开展多种处理技术联合应用研究,末端结合气田开发区域需求状况,探索路基土资源化技术工艺,以最大程度消纳钻井固体废物。

     

    Abstract: The natural gas drilling process generates massive drilling solid waste that contains petroleum hydrocarbon, inorganic salt and refractory organic compounds, etc., which are either poisonous or harmful species. The pH of the water-based drilling solid waste is generally 9-10, which exceeds the technical requirement of Category Ⅰ field storage and backfill of general industrial solid waste stipulated by Standard for Pollution Control on the Storage and Disposal for General Industrial Solid Wastes (GB 18599-2001). The petroleum hydrocarbon content is 4 690-15 500 mg/kg, exceeding the requirements of soil pollution risk screening value of Class Ⅱ land of Soil Environmental Quality Risk Control Standard for Soil Contamination of Development Land(Trial) (GB 36600-2018). The use of oil-based drilling fluid in some gas fields in Sichuan, Chongqing, Xinjiang, etc., due to the complexity of terrain, may lead to over standard concentrations of heavy metals, polycyclic aromatic hydrocarbons (PAHs) and petroleum hydrocarbons. The drilling solid waste is mainly composed of SiO2, CaO, Al2O3, with the total content of three components can reach 72%, which contains the necessary chemical compositions for the preparation of building materials. Based on the pollution characteristics and chemical components of drilling solid waste, the solid waste disposal technologies (including curing stabilization, biodegradation, chemical leaching, downhole reinjection, source reduction technology, etc.) were systematically summarized and analyzed both at home and aboard. Further discussion was made on the characteristics and treatment effect of the technologies, as well as the research progress of resource utilization such as brick-making, wellsite roadway paving, modifier, etc. It was proposed that various treatment and disposal technologies can effectively reduce the pollutants in the drilling solid waste, and diversified resource utilization approaches can improve the utilization rate of solid waste, which tends to be prospective. It was suggested that separate treatment should performed for the drilling solid waste at the source, and multiple treatment technologies should be carried out in the process. At the end of pipe, the technologies of subgrade soil resource utilization should be explored to consume the drilling solid waste to the maximum extent, combined with the demand of gas field development area.

     

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