塔河油田深井碳酸盐岩储层欠平衡钻井技术难点与对策

塔河油田碳酸盐岩储层溶洞、裂隙发育，钻井液密度安全窗口小，欠平衡钻井工艺存在设备配套要求的多样性、欠压值设计难、井底负压控制难、置换性漏失时压井难和强行完井难等技术难点，根据置换性漏失、强行完井施工等要求对井口、井下设备在标准配置的基础上进行了调整，依据碳酸盐岩储层、探井施工的特点提出了循环渐进、灵活的欠压值控制方法，改进的反循环压井技术比平推压井方法减少了压井作业对储层带来的伤害，结合压力传播速度和立管压力值进行井底压力控制的方法提高了压力控制的精度。

Challenges and Solutions of Underbalanced Drilling in Carbonate Reservoirs in Tahe Oilfield

When underbalancedly drilling carbonate reservoirs with developed caves and fractures in Tahe Oilfield, there exist narrow mud density window, various supporting requirements for underbalanced drilling equipment, uncertain underpressure, difficulties in controlling of bottom hole underpressure and killing well while displacemental leaking and forced well completion, etc. . Downhole equipment is adjusted based on standard assemblies to meet demands for displacement losses and forced well completion. Allowing for characteristics of carbonate reservoirs and explorative drilling, this paper presents circular, progressive and flexible control methods for a specified underpressure value. Improved reverse circulating killing techniques creates less killing damages to reservoirs than the normal one. The bottom hole pressure control method combined with pressure wave velocity and standpipe pressure improves pressure control accuracy.