多分支水平井岩屑运移模型与实验研究

Model and experimental research of cuttings transport in multi-branch horizontal wells

摘要:

随着多分支水平井及复杂结构井钻井技术的不断发展，井眼清洁技术面临着新的困难和挑战。如何解决复杂地质条件与复杂井型条件下的岩屑床问题，对于判断与处理井下复杂情况是当前钻井工程面临的重要科学问题之一。通过岩屑颗粒受力分析建立了岩屑运移环空临界流速模型；基于室内可视化岩屑运移实验，探究了岩屑运移影响规律。结果表明：井斜角为36°时岩屑临界启动速度最大，携岩最为困难；模型预测结果与实验结果吻合度较好，且基于实例井的预测结果与现场作业情况一致，验证了所建模型的可靠性。该研究可为大位移大井斜井及水平井井眼清洁提供理论依据和技术支持。

Abstract:

With the technological development of multi-branch horizontal wells and complex structural wells， hole cleaning technology is facing new difficulties and challenges. The problems urgent to be resolved are how to solve the problem of cuttings-bed under complex geological conditions and complex well type conditions， to help judge and solve the complex situation downhole. The cuttings transport model is adopted based on the mechanism of cuttings transport. The indoor visualization of cuttings transport experiments was conducted to analyzed the cuttings transport patterns. The results show that the critical velocity of drill cutting is the highest at the well slope angle of 36°， and the drill cutting is most difficult to be carried. The trend of model predicted was validated by comparison with experimental results， and a good accordance was obtained. Its field application also indicates a good agreement between prediction and actual situations， which validated the reliability of this model. The model and experiments are of reference significance for borehole cleaning of large displacement horizontal wells.