Wang Huipeng, Yang Changhua, Zhang Yongwei, Wang Chen
School of Petroleum Engineering, Xi'an Shiyou University, Xi'an 710065, China.
Gels. 2024 Jul 9;10(7):449. doi: 10.3390/gels10070449.
In order to solve the problem of gas channeling during CO flooding in low-permeability reservoirs, a novel CO responsive gel channeling system was prepared by using carrageenan, branched polyethylene imide and ethylenediamine under laboratory conditions. Based on the Box-Behnken response surface design method, the optimal synthesis concentration of the system was 0.5 wt% carrageenan, 2.5 wt% branchized polyethylenimide and 6.5 wt% ethylenediamine. The micromorphology of the system before and after response was characterized by scanning electron microscopy. The rheology and dehydration rate were tested under different conditions. The channeling performance and enhanced oil recovery effect of the gel system were simulated by a core displacement experiment. The experimental results show that the internal structure of the system changes from a disordered, smooth and loosely separated lamellae structure to a more uniform, complete and orderly three-dimensional network structure after exposure to CO. The viscosity of the system was similar to aqueous solution before contact with CO and showed viscoelastic solid properties after contact with CO. The experiment employing dehydration rates at different temperatures showed that the internal structure of the gel would change at a high temperature, but the gel system had a certain self-healing ability. The results of the displacement experiment show that the plugging rate of the gel system is stable at 85.32% after CO contact, and the recovery rate is increased by 17.06%, which provides an important guide for the development of low-permeability reservoirs.
为解决低渗透油藏CO驱过程中的气窜问题，在实验室条件下，以卡拉胶、支化聚乙烯亚胺和乙二胺为原料制备了一种新型CO响应凝胶调驱体系。基于Box-Behnken响应面设计方法，该体系的最佳合成浓度为0.5 wt%卡拉胶、2.5 wt%支化聚乙烯亚胺和6.5 wt%乙二胺。采用扫描电子显微镜对体系响应前后的微观形貌进行了表征。测试了不同条件下的流变学和脱水率。通过岩心驱替实验模拟了凝胶体系的调驱性能和提高采收率效果。实验结果表明，体系在接触CO后，内部结构由无序、光滑、松散分离的片层结构转变为更加均匀、完整、有序的三维网络结构。体系在接触CO前的粘度与水溶液相似，接触CO后表现出粘弹性固体特性。不同温度下脱水率的实验表明，凝胶在高温下内部结构会发生变化，但凝胶体系具有一定的自愈能力。驱替实验结果表明，凝胶体系在接触CO后的封堵率稳定在85.32%，采收率提高了17.06%，为低渗透油藏的开发提供了重要指导。
