一种延迟凝胶硅酸类堵水剂的研究

Study on Delayed Gelating Silicate-Based Plugging Agent

针对孤岛油田中高渗透率的情况,在油田污水中以水玻璃和甲基硅酸钠为主剂,加入磷酸和缓释酸(A酸),研制了一种可延迟凝胶的硅酸类堵水剂。在常压和模拟地层温度(60℃)下,考察各组分用量对堵剂性能的影响。结果表明,甲基硅酸钠改善了硅酸凝胶的性能,使凝胶具有更好的强度和弹性。A酸缓慢释放H+,达到延迟凝胶的目的。堵剂的凝胶时间随水玻璃和A酸用量的增加而缩短,随甲基硅酸钠用量的增加而延长,在磷酸用量为0.3 mL时出现极大值。堵剂总体积为100 mL,当水玻璃10 mL,甲基硅酸钠5 mL,磷酸0.3 mL,A酸20 mL,油田污水64.7 mL时,可以形成具有良好强度的凝胶,凝胶时间最长为13.5 h。

A delayed gelating silicate-based plugging agent was developed by sodium silicate, methyl sodium silicate, phosphoric acid and slow-release acid（A acid） with oilfield wastewater for high permeability oilfidd in Gudao. Effects of each composition＇s proportion on the performance of plugging agent were investigated under atmospheric pressure and 60℃ which simulated the temperature of formation. It was shown that methyl sodium silicate improved the performance of silicie acid gel, such as the strength and elastic properties. A acid released H＋ slowly to achieve the objective of delayed gel forming. The gelation time decreased with increasing amounts of sodium silicate and A acid, and increased with increasing amount of methyl sodium silicate. The maximum value obtained when the dosage of phosphoric acid was of 0.3 mL. While the total volume of plugging agent was of 100 mL mixed with 10 mL sodium silicate, 5 mL methyl sodium silicate, 0.3 mL phosphoric acid, 20 mL A acid and 64.7 mL oilfield wastewater, the gel with good strength formed and the longest gelation time was of 13.5 hrs.