磨溪-高石梯上部井段优快钻井钻井液技术

磨溪-高石梯上部井段地层互层多、胶结性差,井壁失稳风险大,以及大段泥岩、石膏导致的污染,制约着该区块钻井提速进程。根据该区块地层特点,通过KCl、weigh-2、疏水抑制剂CQ-SIA的复配,优选出双盐-疏水聚合物钻井液体系。室内评价效果表明,该钻井液体系失水造壁性好、抑制封堵性强,中压失水3.2 mL,滚动回收率99.46%,15%(w)泥岩污染和3%(w)石膏污染对钻井液性能影响小。高石001-X38井现场应用表明,双盐-疏水聚合物钻井液体系能够有效解决上部井段泥岩水化分散、钻头泥包、地层井壁失稳、石膏污染等技术问题,创造了高石001区块311.2 mm井眼最短钻进周期18.68天、最快机械钻速8.46 m/h两项记录。

Drilling fluid technology for safe and fast drilling in upper section of Moxi-Gaoshiti block

There are many inter stratigraphic layers of the upper section of Moxi-Gaoshiti block. The characters of poor cementation, the high risk of borehole wall instability, and the pollution of mudstone and gypsum restrict the process of drilling speed increase in this area. According to the formation characteristics, through the compounding of KCl, weigh-2 and hydrophobic inhibitor CQ-SIA, then the double salt-hydrophobic polymer drilling fluid system is optimized. The indoor evaluation results show that the drilling fluid system has good wall-building performance, strong inhibition and plugging performance. The water loss is 3.2 mL, rolling recovery rate is 99.46%, and 5 w% mudstone pollution and 3 w% gypsum pollution have little effect on drilling fluid performance. The field applications show that the double salt-hydrophobic polymer drilling fluid system can effectively solve the technical problems of mudstone hydration dispersion, bit balling, formation wellbore instability and gypsum pollution in the upper section. Two records have been created for 311.2 mm borehole in Gaoshi 001 block, which are the shortest drilling period of 18.68 days and the fastest ROP of 8.46 m/h.