Zhang Xianfa, Liu Jingping, Sun Jinsheng, Lv Kaihe, Wang Zonglun, Xu Zhe, Sun Yuanwei
School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China.
CNPC Engineering Technology R & D Company Limited, Beijing 102206, China.
Gels. 2023 Sep 19;9(9):763. doi: 10.3390/gels9090763.
Ensuring wellbore stability is of utmost importance for safety when drilling in deep formations. However, high temperatures severely disrupt the drilling fluid gel system, leading to severe stability issues within ultra-deep formations containing micropores. This study focused on the development of a polymer-based plugging material capable of withstanding high temperatures up to 200 °C. A kind of microsphere, referred to as SST (styrene-sodium styrene sulfonate copolymer), was synthesized with a particle size of 322 nm. Compared to polystyrene, the thermal stability of SST is greatly improved, with a thermal decomposition temperature of 362 °C. Even after subjecting SST to hot rolling at 200 °C for 16 h, the particle size, elemental composition, and zeta potential remained stable within an aqueous dispersion system. The results of core displacement and NMR tests demonstrate that SST considerably reduces the pore diameter with a remarkable plugging efficiency of 78.9%. Additionally, when drilling fluids reach 200 °C, SST still enhances drilling fluid suspension and dispersion, and reduces fluid loss by over 36% by facilitating the dispersion of clay particles, improving the gel structure of the drilling fluid, resisting clay dehydration, and promoting plugging. The development of SST provides valuable insights into the preparation of high-temperature-resistant microspheres and the formulation of effective plugging agents for deep-well drilling fluids.
在深层地层钻井时，确保井筒稳定性对安全至关重要。然而，高温会严重破坏钻井液凝胶体系，导致含微孔的超深层地层出现严重的稳定性问题。本研究聚焦于开发一种能承受高达200℃高温的聚合物基堵漏材料。合成了一种粒径为322nm的微球，称为SST（苯乙烯-苯乙烯磺酸钠共聚物）。与聚苯乙烯相比，SST的热稳定性大大提高，热分解温度为362℃。即使将SST在200℃下热轧16h后，其在水分散体系中的粒径、元素组成和zeta电位仍保持稳定。岩心驱替和核磁共振测试结果表明，SST能显著减小孔径，堵漏效率高达78.9%。此外，当钻井液温度达到200℃时，SST仍能增强钻井液的悬浮和分散性能，通过促进粘土颗粒分散、改善钻井液凝胶结构、抵抗粘土脱水和促进堵漏，使滤失量降低超过36%。SST的开发为耐高温微球的制备以及深井钻井液有效堵漏剂的配方提供了有价值的见解。
