微粉加重剂与普通重晶石复配加重油基钻井液性能

针对超高密度油基钻井液固相含量高给钻井液性能调控与维护带来不便的问题。用激光粒度分析仪和扫描电镜分析了微粉重晶石、微锰矿粉、普通重晶石的粒度分布和微观形态，研究了微粉加重材料与普通重晶石按不同比例复配加重得到的超高密度油基钻井液的性能变化，同时通过改变处理剂加量对超高密度油基钻井液加重配方进行了调控。研究结果表明，微粉加重材料与普通重晶石按不同比例复配后加重的超高密度油基钻井液具有良好的流变性、电稳定性和失水造壁性，微粉重晶石与普通重晶石的最优复配比例5:5~6:4，微锰矿粉与普通重晶石复配时，微锰矿粉所占复配比例越大，其体系性能越好。考虑到加重材料的成本，室内采用微粉重晶石与普通重晶石3:7、微锰矿粉与普通重晶石2:8的复配比例加重超高密度油基钻井液，在此基础上通过调节有机土和乳化剂的加量、改变内相来优化加重配方，形成了性能良好的超高密度油基钻井液体系。

Properties of oil-based drilling fluid weighted by the combination of micronized weighting agent and common barite

The high solid content of oil-based drilling fluid of ultrahigh density makes it inconvenient for its property control and maintenance. To solve this problem, the particle size distribution and microscopic morphology of micronized barite, micro manganese ore powder and common barite were analyzed indoors by means of laser particle size analyzer and scanning electron microscope (SEM) respectively. The properties of the oil-based drilling fluids of ultrahigh density weighted by the combination of micronized weighting agent and common barite at different proportions were investigated. And the weighting formula for the oil-based drilling fluids of ultrahigh density was controlled by changing the dosage of treating chemical. It is indicated that the oil-based drilling fluids of ultrahigh density which is weighted by the combination of micronized weighting agent and common barite at different proportions is better than that weighted by the common barite in terms of rheological property, electrical stability and wall building property. The optimal combination proportion between micronized barite and common barite is 5:5-6:4. When micro manganese ore powder and common barite are combined, the higher the proportion of micro manganese ore powder is, the better the property of the system is. Considering the cost of micronized barite and micro manganese ore powder, the oil-based drilling fluids of ultrahigh density is weighted indoors by setting the proportion between micronized barite and common barite as 3:7 and the proportion between micro manganese ore powder and common barite as 2:8. Based on this, the weighting formula is optimized by adjusting the dosage of organic clay and emulsifier and changing the internal phase. Thus, the oil-based drilling fluid of ultrahigh density with good properties is prepared.