钻井液中暂堵剂颗粒尺寸分布优选的新理论和新方法

New theory and method for optimizing the particle size distribution of bridging agents in drilling fluids

应用颗粒堆积效率最大值原理 ,阐述了优选钻井液中暂堵剂颗粒尺寸的“理想充填”理论和d90 规则 ,提出了一种特别有利于对中、高渗透储层实施暂堵和保护的新方法。依据该方法研制和开发的配套软件能够根据相关地层参数 ,快速、准确地对具有不同粒径的暂堵剂产品按一定比例进行合理的复配组合。实验结果表明 ,优选出的复配暂堵方案能有效地使钻井液中的暂堵剂形成致密泥饼。与传统方法相比 ,岩心的渗透率恢复值明显提高 ,从而能有效地阻止钻井液中固相颗粒和滤液侵入油气层。

The 'Ideal Packing Theory' and the d90 rule used for optimizing the particle size distribution were elaborated by applying the principle of maximum packing efficiency. A new method beneficial to bridge and protect medium-permeability and high-permeability formations was proposed. The software developed with this method can be used to precisely and quickly select and recombine the bridging agents with different particle size in a given proportion based on the relative parameters of formations. The experimental results indicate that the optimized recombination of several bridging agents can effectively make the bridging agents form compacted mud cake and obviously return permeability of core samples. This method can effectively prevent solid particles and filtrate from invasion into formations.