针对RT1井目的层岩性易水化膨胀、井底温度高且易发生碳酸氢根污染的难题, 通过分析地层特点及钻井液技术难点, 优选有机盐、降滤失剂及封堵剂等关键处理剂, 研制了抗高温复合盐钻井液配方。室内实验结果发现: 该钻井液体系抗温达到180℃, 热滚8d上下密度差仅为0. 06g/cm3, HTHP滤失量小于4mL, 16h膨胀率仅为0. 88%, 二次滚动回收率达92%, 岩心封堵率达75%以上, 抗碳酸氢根污染大于22000mg/L, 具有良好的流变性能、滤失性能、抑制性 能、封堵性能、抗碳酸氢根污染性能及沉降稳定性能。现场实验结果表明: 二开下部及三开井径扩大率仅为3. 8%, 井底170℃下钻井液仍具有良好的流变性, 钻井液中碳酸氢根离子浓度30230mg/L时性能稍有变化, 说明研制的抗高温有机盐钻井液有效地解决了RT1井目的层泥岩易水化膨胀分散、井底温度高及碳酸氢根污染等难题, 在高温深井中具有广阔的应用前景。

In response to the difficult problem that the lithology of the target formation of Well RT1 is prone to hydrate and expand, the bottom hole temperature is high, and bicarbonate pollution is prone to occur, by analyzing the formation characteristics and technical difficulties of drilling fluids, and preferentially selecting key treatment agents such as organic salts, filtrate reducers and blocking agents, the formulation of high temperature resistant organic salt drilling fluid is developed. The results of laboratory experiments show that the drilling fluid system is resistant to temperatures up to 180℃, the difference in density between the upper and lower parts is only 0. 06g/cm3 after hot rolling for 8 days, the HTHP filtration loss is less than 4 ml, the 16-hour expansion rate is only 0. 88%, the secondary rolling recovery rate reaches 92%, the core blocking rate is more than 75%, and the resistance to bicarbonate contamination is more than 22000mg/L. It has good rheological properties, filtration properties, inhibition performance, plugging performance, anti-bicarbonate pollution performance and sedimentation stability performance. The results of the field experiment show that the good diameter expansion rate of the lower part of the two-open lower and the three-open lower is only 3. 8%, the drilling fluid still has good rheological properties at 170℃, and the performance varies slightly when the bicarbonate ion concentration in the drilling fluid is 30230mg/L. It indicates that the developed high temperature resistant organic salt drilling fluid has effectively solved the difficult problems of easy hydration, expansion and dispersion of the mudstone in the target layer of well RT1, high temperature at the bottom of the well and bicarbonate contamination, and has broad application prospects in high-temperature deep wells.