低土相高密度钻井液体系的配方研制

针对高密度钻井液体系普遍存在的黏度偏大、流变性难以调控、经常出现井下复杂情况等问题，通过对聚合物包被剂、膨润土含量、润滑剂、抑制剂的优选，确定了低土相高密度钻井液体系的最佳配方，开发了一套低土相高密度钻井液体系。室内研究结果表明，该钻井液体系具有良好的抗钻屑、NaCl和石膏的污染能力和良好的抑制封堵能力，岩屑滚动回收率达到93．7％，能够满足高温高压、严重造浆、高渗透率以及微裂缝发育等复杂地层的钻井技术要求。

Study on high density drilling fluid system with low clay phase

In view of great viscosity in high density drilling fluid system, rheology behavior is difficult to regulate and control, down hole problems emerges frequently. By means of optimizing polymer flocculant, bentonite content, lubricant, inhibitor, the best formula of high density drilling fluid system with low day phase is defined and a suit of higla density drilling fluid system with low day phase is developed. Laboratory study results demonstrated that the drilling fluid system has good potential resistance to cuttings, NaC1 and gypsum contamination, good inhibition and formation sealing ability, and cuttings roiling recovery achieves 93.7 %. The drilling fluid system can satisfy the drilling technology demands of high temperature and high pressure, strong mud-making, high penetration rate and mature micro-fissure development.