Summary Lost circulation materials (LCMs) are essential to combat fluid loss while drilling and may put the whole operation at risk if a proper LCM design is not used. The focus of this research is understanding the function of LCMs in sealing fractures to reduce fluid loss. One important consideration in the success of fracture sealing is the particle-size distribution (PSD) of LCMs. Various studies have suggested different guidelines for obtaining the best size distribution of LCMs for effective fracture sealing based on limited laboratory experiments or field observations. Hence, there is a need for sophisticated numerical methods to improve the LCM design by providing some predictive capabilities. In this study, computational fluid dynamics (CFD) and discrete element methods (DEM) numerical simulations are coupled to investigate the influence of PSD of granular LCMs on fracture sealing. Dimensionless variables were introduced to compare cases with different PSDs. We validated the CFD-DEM model in reproducing specific laboratory observations of fracture-sealing experiments within the model boundary parameters. Our simulations suggested that a bimodally distributed blend would be the most effective design in comparison to other PSDs tested here.

中文翻译：

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裂缝密封损失循环材料粒度分布的评估：数值研究

总结 漏失材料 (LCM) 对于防止钻井过程中漏失至关重要，如果不使用适当的 LCM 设计，可能会使整个作业面临风险。本研究的重点是了解 LCM 在密封裂缝以减少流体损失中的功能。裂缝密封成功的一个重要考虑因素是 LCM 的粒度分布 (PSD)。基于有限的实验室实验或现场观察，各种研究提出了不同的指导方针，以获得 LCM 的最佳尺寸分布以进行有效的裂缝密封。因此，需要复杂的数值方法通过提供一些预测能力来改进 LCM 设计。在这项研究中，计算流体动力学 (CFD) 和离散元方法 (DEM) 数值模拟相结合，以研究粒状 LCM 的 PSD 对裂缝密封的影响。引入了无量纲变量来比较具有不同 PSD 的案例。我们验证了 CFD-DEM 模型在模型边界参数内重现裂缝密封实验的特定实验室观察结果。我们的模拟表明，与此处测试的其他 PSD 相比，双峰分布的混合将是最有效的设计。