适合小井眼水平井的水基钻井液体系研究

Study on Water-based Drilling Fluid System Suitable For Slim Hole Horizontal Wells

通过分析小井眼水平井钻井液的技术特点,并结合处理剂的优选实验,研制一套适合小井眼水平井的水基钻井液体系,并对其综合性能进行了评价。结果表明:该钻井液体系具有良好的流变性能、滤失性能和耐温性能,经过150℃老化后,体系的黏度和切力变化不大,滤失量较小;体系具有良好的抑制性,对岩屑的滚动回收率可以达到90%以上;体系还具有良好的润滑性和抗污染性能,在体系中加入不同质量浓度的盐和岩屑后,体系的性能仍能保持稳定;另外,使用钻井液体系污染后的岩心,渗透率恢复值可以达到75%以上,而切除污染端面0.5 cm后,其渗透率恢复值可以达到95%以上,说明钻井液体系具有良好的储层保护性能,能够满足小井眼水平井钻井施工的要求。

A water-based drilling fluid system suitable for slim hole horizontal wells was developed by analyzing the technical characteristics of the drilling fluid and combining with the optimization experiment of treating agent,and its comprehensive performance was evaluated.The results showed that the drilling fluid system had good rheological properties,filtration and temperature resistance.After aging at 150℃,the viscosity and shear force of the system changed little,and the filter loss was small;the system had good inhibition,and the rolling recovery rate of rock cuttings was more than 90%;the system also had good lubricity and pollution resistance,and after adding different mass concentrations of salt and cuttings to the system,the performance of the system still remained stable.In addition,the permeability recovery value of the core polluted by the drilling fluid system was more than 75%,and the permeability recovery value was more than 95%after 0.5 cm of the contaminated end face was removed,which showed that the drilling fluid system had good reservoir protection performance and met the requirements of drilling construction of small horizontal well.