关键词: 低压油气藏, 欠平衡钻井, 微泡沫发泡剂, 微泡沫钻井液, 稳定性

Abstract: Based on the theoretical model of micro-foam microstructure and erformance,a micro-foam agent MF-1 was synthesized in labo-ratory.The performance evaluation shows that the temperature resistance capability of MF-1 is over 150℃,and the salt resistance capability is over 10 percent,and the calcium resistance capability is over 5g/L.Based on the micro-foam agent MF-1,the micro-foam drilling fluid system with a good performance was developed.The microstructure of the micro-foam drilling fluid was analyzed by microscopy.The result shows that the bubbles of micro-foam drilling fluid are suspended in single or partially connected in dot in the plane.The shape of the bubble is round,and the volume is unequal.The density of the drilling fluid changes from 0.6 g/cm³ to 0.95 g/cm³.The application of the micro-foam drilling fluid in Jin 45-15-26C Well showed that the performance of this kind of drilling fluid was stable,and the gas-liquid phase was not layered in the whole drilling process.The foam of the drilling fluid was fine,and the operation of mud pump was normal.The perfor-mances of the micro-foam drilling fluid can meet the demand of the actual drilling process.

Key words: low-pressure reservoir, under balanced drilling, micro-foam agent, micro-foam drilling fluid, stability