针对缅甸D区块钻井过程中存在的井壁失稳问题，系统分析了缅甸D区块易塌井段泥页岩黏土矿物组分、岩石微观结构、泥页岩水化性能，结合现场实际对前期钻井液存在的问题进行分析，优化出适宜缅甸D区块特点的非渗透性防塌钻井液配方。室内性能评价表明，该非渗透性防塌钻井液具有较强的抗污染能力、抗温能力，泥页岩抑制能力以及封堵能力。在现场应用4口井过程中，该钻井液取得了较好的井眼稳定效果，可有效解决缅甸D区块井眼坍塌和井径扩大率的问题，显著降低了井下复杂事故的发生。

During the drilling in Block D in Myanmar, the wellbore collapse, the abnormal drill torque and the bit broken falling cuttings were repeatedly encountered, the rate of penetration was reduced, and the drilling progress was seriously affected. This paper focuses on the wellbore instability problems in the process of drilling and developes a drilling fluid system suitable for this block, to improve the drilling speed, reduce the downhole complex accidents. The shale clay composition, the microstructure and the hydration performance of the collapse-prone section in Myanmar block D are analyzed. In view of the existing problems of the early used drilling fluid, the appropriate impermeable and anti-collapse drilling fluid formulation is optimized. The laboratory experiment and evaluation results show that the impermeable and anti-collapse prevention drilling fluids have a strong ability to resist pollution, a good temperature resistance, good clay shale inhibition ability and block ability. In the process of the field application in 4 wells, the drilling fluid shows a good effect on the wellbore stability and can effectively solve the problems of the borehole collapse and the hole enlargement, significantly reduce the downhole complex accidents.