In the process of drilling for oil and gas, plugging materials are used to effectively plug the formation pores and microfractures and thus ensure the stability of the wellbore. In this work, SiO₂ expansible composite microspheres (SECMs) were prepared by inverse suspension polymerization using SiO₂, vinyltrimethoxysilane, acrylamide, and 2-acrylamido-2-methyl propane sulfonic acid as raw materials. The results of infrared spectroscopy, laser particle size, thermogravimetric analysis, and scanning electron microscopy investigations show that the SECMs are homogeneous. They are spherical in shape with a median particle size of 19.38 μm and a particle size distribution that is relatively uniform. They also have good water absorption and expansion capacity. After 24 h, the average particle size of the SECMs was 34.4 μm, which was 77% higher than the average particle size before water absorption. The SECMs were further investigated by adding them to a low-solid water-based drilling fluid containing 4 wt% bentonite. Plugging tests carried out using the drilling fluid showed that the SECMs can significantly reduce the filtration rate of the drilling fluid. A 0.6 wt% dose of the SECMs led to a FL_API value of 13 mL. This dropped to 11 mL after aging at 150 °C for 16 h. This shows that the SECMs have a good resistance to high temperatures and that the soft shells of the microspheres deform at high temperature which improves the sealing effect in irregularly shaped pores.

中文翻译：

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水性钻井液用SiO 2可膨胀复合微球的制备，表征与性能

在油气钻探过程中，采用堵漏材料有效堵住地层孔隙和微裂缝，从而保证了井筒的稳定性。在这项工作中，通过使用SiO _2的反向悬浮聚合制备了SiO ₂可膨胀复合微球（SECM）。，乙烯基三甲氧基硅烷，丙烯酰胺和2-丙烯酰胺基-2-甲基丙烷磺酸为原料。红外光谱，激光粒度，热重分析和扫描电子显微镜研究的结果表明，SECM是均匀的。它们为球形，中值粒径为19.38μm，粒径分布相对均匀。它们还具有良好的吸水和膨胀能力。24小时后，SECM的平均粒径为34.4μm，比吸水前的平均粒径高77％。通过将SECM添加到含有4 wt％膨润土的低固含量水基钻井液中来进一步研究。使用钻井液进行的堵漏测试表明，SECM可以显着降低钻井液的过滤速率。0.6 wt％剂量的SECM导致FL_API值为13毫升。在150°C下老化16小时后，其降至11 mL。这表明SECM对高温具有良好的抵抗力，并且微球的软壳在高温下会变形，从而改善了不规则形状的孔中的密封效果。