高矿化度油藏用聚丙烯酰胺封堵凝胶的制备及性能

Preparation and evaluation of polyacrylamide gels for deep reservoir profile control

摘要:

深层油藏在开采过程中易发生底水上窜,地层水进入油藏影响采收率。由于地层水矿化度高,常规凝胶成胶效果差,强度低,封堵效果差。为解决这一问题,采用丙烯酰胺(AM)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)、4-丙烯酰吗啉(ACMO)制备耐温耐盐稠化剂TS-2。通过FIIR和1H NMR表征,表明TS-2成功合成。以乙酸铬为交联剂制备高温耐盐缓交联封堵凝胶TSP-2,在150℃下成胶时间为6d,最终表观粘度为94400cP。通过SEM表征、粘弹性测试与封堵性测试可知,TSP-2具有丰富且有序的交联网络结构,使其在不同剪切应力与频率下均具有稳定的内部结构,在400~900mD范围内的填砂管,均有良好的封堵效果,封堵率在96.12%以上,突破压力梯度可达4.52MPa/m以上。

Abstract:

Deep reservoirs are prone to bottom water channeling in the production process, and formation water entering the reservoir affects the recovery efficiency. Due to the high salinity of formation water, conventional gels have poor gelling effect, low strength and poor sealing effect. In order to solve this problem, the temperature and salt-resistant thickener TS-2 was prepared by acrylamide (AM), 2-acrylamide-2-methylpropanesulfonic acid (AMPS) and 4-acrylylmorpholinium (ACMO). TS-2 was successfully synthesized by FIIR and 1H NMR. The high temperature salt-resistant and slow crosslinking gel TSP-2 was prepared by using chromium acetate as crosslinking agent. The gel formation time was 6d at 150℃, and the final apparent viscosity was 94400cP. Through SEM characterization, viscoelastic testing and plugging ability testing, it can be seen that TSP-2 has a rich and ordered cross-linked network structure, which makes it have a stable internal structure under different shear stress and frequency. The sand filled pipe in the range of 400~900mD has a good plugging effect, and the plugging rate is more than 96.12%. The breakthrough pressure gradient can reach more than 4.52MPa/m.