紧密堆积优化固井水泥浆体系堆积密实度

Packing compactness of cementing slurry system for close packing optimization

紧密堆积技术是高性能固井水泥浆体系设计关键技术,对提高固井水泥浆性能具有重要意义,其核心是提高颗粒体系的堆积密实度。为此,选用可压缩堆积模型作为紧密堆积理论模型,确定了模型参数和数值计算方法,编制了堆积密实度计算程序并对计算结果进行了验证;通过计算多元颗粒体系的堆积密实度,对影响颗粒体系堆积密实度的因素进行了分析,并进行了水泥浆设计和性能试验。研究结果表明,适当增加超细颗粒组分、合理优化粒径分布区间、提高颗粒体系的大小颗粒平均粒径比可以有效提高堆积密度,相比三元体系,含有纳米材料的五元体系可达到颗粒体系的最紧密堆积,水泥浆性能更好。利用紧密堆积模型指导油井水泥体系干混配比设计具有可行性。

Close packing technology, as the key technology for the design of high-performance cementing slurry system, is of great significance to improve the performance of cementing slurry, and its core is to increase the packing compactness of grain system. The compressible packing model was taken as the theoretical model of close packing, and model parameters and numerical calculation methods were ascertained. Calculation program of packing compactness was worked out and its calculation results were verified. The factors influencing the packing compactness of grain system were analyzed by calculating the packing compactness of multi-grain system. Finally, slurry was design and its performance was tested. It is indicated that the packing compactness can be improved effectively by adding ultrafine grain compositions moderately, optimizing size distribution interval appropriately and increasing average diameters of large and small grains in the grain system. Compared with ternary system, quinary system with nano materials has the closest packing of grain system and presents better slurry performance. It is feasible to take the close packing model as the guide for the design of dry mixing ratio of cement system used in oil wells.