低毒环保型油基钻井液体系室内研究

Experimental Study on Low-Toxicity and Environment-Friendly Oil-Based Drilling Fluids

为了提高油基钻井液的环保性能,解决其生物毒性高、难于降解等问题,研制了低毒环保型油基钻井液。通过对普通原料油进行脱硫脱芳处理得到新型低毒油基钻井液用基础油,采用复合改性剂和新工艺处理有机土得到新型改性有机土,并对钻井液处理剂及加量进行优选,最终形成了低毒环保型油基钻井液体系。室内试验结果表明,该钻井液体系的高温高压滤失量为3.2~9.5mL,沉降密度差最高0.06g/cm3,破乳电压高达1 190V以上,水侵和劣质土侵后乳化体系还可以保持稳定,二次岩屑回收率达到99.17%,线性膨胀率仅为1.92%,岩心渗透率恢复率达88.5%~94.6%。研究结果表明,低毒环保型油基钻井液体系的流变性、稳定性、抗污染性、润滑性、抑制性和储层保护性能良好,可满足复杂地层深井、超深井安全高效钻井的需求及环保要求。

To enhance the environmental protection performance of oil-based drilling fluids,and to eliminate problems related to the biological toxicity and difficulties in the degradation of conventional drilling fluids,an innovative low-toxicity and environment friendly oil-based drilling fluid has been developed.During its development,normal raw oil was primarily processed into base oil through desulfurization and dearomatization,then composed modifiers with innovative techniques were deployed to generate modified organic clay.Eventually,a low-toxicity oil-based drilling fluid system was generated through the optimization of additives and added specific volumes of such additives in the drilling fluid.Experimental results show that the innovative drilling system has filtration losses of 3.2-9.5mL,a maximum differential precipitation density of 0.06g/cm3 and ES over 1 190 Vunder high pressure and high pressure.In addition,the emulsion system can maintain desirable stability after water or low-quality clay invasion with a secondary cutting recovery rate of 99.17%,linear expansion rate of 1.92%and permeability recovery rate 88.5%-94.6%.Research results show that the newly developed low-toxicity and environmental-friendly oil-based drilling fluid system possesses outstanding rheological properties,stability,anti immersion,lubrication,inhibition and reservoir protection performances and can meet the requirements for safe and high-efficiency drilling and environmental protection in complex formations in the drilling of deep and ultra-deep wells.