为获得低油水比下性能稳定的油基钻井液，油包水乳状液的稳定性是关键。通过电稳定性测试法、静态稳 定性测试法、微观形态测试法分析了乳化剂加量、有机土加量和温度对油水比为60∶40的油包水乳状液稳定性的 影响。研究结果表明：4%乳化剂加量下乳液滴细小且分散均匀，破乳电压最高，乳状液稳定性最佳。环境温度 100 ℃和120 ℃下，乳状液液滴大小变化不大，破乳电压接近，稳定性差别不大，继续提高温度至150 ℃，乳状液 液滴显著增大，破乳电压陡降，稳定性明显变差。有机土加量为2%时，显微镜放大400倍下乳状液液滴肉眼不可 见，破乳电压超过400 V，且静置25 h后析油率仅0.1%，稳定性显著提高。通过关键处理剂材料作用机理分析并 优选合适处理剂加量，是保证低油水比乳状液稳定的一大关键，对现场油基钻井液性能维护有实际指导意义。
In order to obtain oil-based drilling fluids with stable performance at low oil to water ratios，the stability of water-in-oil emulsions is critical. The effects of emulsifier addition，organic soil addition and temperature on the stability of water- in- oil emulsion with oil-water ratio of 60/40 were analyzed by electrical stability test，static stability test and micro-morphometry. The results showed that when the addition of the emulsifier was 4% ，the emulsion droplets were fine and dispersed evenly，the demulsification voltage was the highest and the emulsion stability was the best. At the temperature of 100 ℃ and 120 ℃，the emulsion droplet size changed little，and the demulsification voltage was close，indicating that there was little difference on stability. However，when the temperature increased up to 150 ℃，the emulsion droplets augmented significantly，the demulsification voltage droped sharply，stability significantly deteriorated. When adding 2% organic soil，the emulsion droplets under 400 times objective lens were invisible to the naked eye，the demulsification voltage exceeded 400 V，and the oil separation rate was only 0.1% after standing for 25 hours，as a result，the stability was remarkably improved. Analyzing the mechanism of key materials and optimizing the amount of appropriate treatment agent were important to ensuring the stability of emulsions with low oil-to-water ratio，which had practical guiding significance for on-site oil-based drilling fluid performance maintenance.