Zhang Xianfa, Liu Jingping, Sun Jinsheng, Wang Zonglun, Dai Zhiwen, Sun Yuanwei, Zhang Taifeng
School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China.
CNPC Engineering Technology R & D Company Limited, Beijing 102206, China.
Materials (Basel). 2023 Sep 6;16(18):6096. doi: 10.3390/ma16186096.
With the gradual depletion of shallow oil and gas, deep oil and gas has become the focus of development. However, deep formations generally face the challenge of high-temperature and high-salinity, and drilling fluid agents are prone to failure, leading to drilling fluid intrusion into the formation that can cause serious drilling accidents such as well bore collapse. For this, a styrene-based nano-microsphere (SSD) modified with amphoteric ions was developed, with a particle size of 228 nm which could resist temperatures up to 200 °C and sodium chloride (NaCl) up to saturation. SSD has significant salt-responsive properties and its aqueous dispersion becomes transparent with increasing salinity. The SSD provided superior plugging performance in solutions containing NaCl, with a core plugging efficiency of 95.2%, and it was significantly better than the anion-modified microspheres. In addition, in drilling fluids under high temperature and high-salinity conditions, the SSD promotes particle gradation of drilling fluids and improves the zeta potential through its own plugging and synergistic effect with clay, which significantly improves the comprehensive performance of drilling fluids, such as stability, rheological performance, and filtration reduction performance. The development of SSD provides a new idea for research of high-temperature and high-salinity-resistant drilling fluid agents.
随着浅层油气资源的逐渐枯竭，深层油气已成为开发重点。然而，深层地层普遍面临高温高盐的挑战，钻井液处理剂容易失效，导致钻井液侵入地层，引发诸如井壁坍塌等严重钻井事故。为此，开发了一种用两性离子改性的苯乙烯基纳米微球（SSD），其粒径为228纳米，可耐受高达200℃的温度和饱和氯化钠（NaCl）。SSD具有显著的盐响应特性，其水分散体随着盐度增加而变透明。SSD在含NaCl的溶液中具有优异的封堵性能，岩心封堵效率达95.2%，明显优于阴离子改性微球。此外，在高温高盐条件下的钻井液中，SSD通过自身封堵以及与黏土的协同作用促进钻井液颗粒级配，提高zeta电位，显著改善钻井液的稳定性、流变性能和降滤失性能等综合性能。SSD的开发为耐高温高盐钻井液处理剂的研究提供了新思路。
