一种无氯盐环保型强抑制水基钻井液体系

为减少油气资源勘探与开发过程中钻井液对周围环境的污染与生态系统的破坏，实现"绿色"钻井，并尽可能提高钻井液性能，笔者采用研制的包被剂、仿生固壁剂等与优选的处理剂进行复合，研发出了一套无氯盐环保型强抑制水基钻井液体系。室内研究结果表明，该体系在热稳定性、抗污染能力、抑制性能等方面表现优异，在120℃下连续热滚72h后钻井液性能稳定，可抗土粉污染达10%，抗钙侵0.8%，抗盐侵30%，页岩岩屑滚动回收率高达98.5%，抑制性评价结果优于PHPA/KCl体系。该体系能够满足常规环保评价指标，同时避免了使用氯盐，减轻对土壤结构、植物生长和地下水产生的负面影响。半数有效浓度EC₅₀小于106 mg/L，易生物降解比值BOD₅/COD_Cr为0.633，重金属含量远低于标准值，因此，无生物毒性，可降解，可排放。实验数据和评价结果均表明，该体系是一种既能满足钻井工程需求又能保护生态环境的新型水基钻井液体系，有较好的应用前景。 

Development of an Environmentally Friendly Strongly Inhibitive Chloride-free Water Base Drilling Fluid

To minimize environmental pollution and damage to the ecosystem by drilling fluids used in the exploration and development of oil and gas, realize "green" drilling and maximize the performance of a drilling fluid, an encapsulator and a bionic borehole wall strengthening agent previously developed were compounded with other selected additives to formulate an environmentally friendly strongly inhibitive chloride-free water base drilling fluid. Laboratory experimental results show that this drilling fluid has superior temperature stability, resistance to contamination and inhibitive capacity. The drilling fluid had stable properties after continuously hot rolled for 72 h at 120℃. It was resistant to contamination by 10% clays, 0.8% calcium, or 30% salt. Percent shale recovery on hot rolling test was 98.5%. Laboratory evaluation shows that this drilling fluid has performance that is superior to that of PHPA/KCl drilling fluid. This drilling fluid can satisfy the needs of general environment protection and contains no chlorides, minimizing its negative effects on soil structure, plant growth and underground water system. EC50 of this drilling fluid is greater than 106 mg/L and BOD5/CODCr 0.633. The content of heavy metals is far lower than standard requirements, and is thus free of biotoxicity, biodegradable and dischargeable. Experimental data and evaluation results demonstrate that this drilling fluid is a novel mud that both satisfies the needs of drilling operation and protects the environment from being polluted, and has good application prospects.