Shi Bin, Zhang Guangming, Zhang Lei, Wang Chengjun, Li Zhonghui, Chen Fangping
Hubei Key Laboratory of Drilling and Production Engineering for Oil and Gas, School of Petroleum Engineering, Yangtze University, Wuhan 430100, China.
Research Institute of Shaanxi Yanchang Petroleum (Group) Co., Ltd., Xi'an 710075, China.
Gels. 2024 Apr 30;10(5):304. doi: 10.3390/gels10050304.
It is difficult to plug the fracture water channeling of a fractured low-permeability reservoir during water flooding by using the conventional acrylamide polymer gel due to its weak mechanical properties. For this problem, micron graphite powder is added to enhance the comprehensive properties of the acrylamide polymer gel, which can improve the plugging effect of fracture water channeling. The chemical principle of this process is that the hydroxyl and carboxyl groups of the layered micron graphite powder can undergo physicochemical interactions with the amide groups of the polyacrylamide molecule chain. As a rigid structure, the graphite powder can support the flexible skeleton of the original polyacrylamide molecule chain. Through the synergy of the rigid and flexible structures, the viscoelasticity, thermal stability, tensile performance, and plugging ability of the new-type gel can be significantly enhanced. Compared with a single acrylamide gel, after adding 3000 mg/L of micrometer-sized graphite powder, the elastic modulus, the viscous modulus, the phase transition temperature, the breakthrough pressure gradient, the elongation at break, and the tensile stress of the acrylamide gel are all greatly improved. After adding the graphite powder to the polyacrylamide gel, the fracture water channeling can be effectively plugged. The characteristics of the networked water flow channel are obvious during the injected water break through the gel in the fracture. The breakthrough pressure of water flooding is high. The experimental results are an attempt to develop a new gel material for the water plugging of a fractured low-permeability reservoir.
在注水开发过程中,由于常规丙烯酰胺聚合物凝胶力学性能较弱,难以封堵裂缝性低渗透油藏的裂缝窜流通道。针对这一问题,添加微米级石墨粉以增强丙烯酰胺聚合物凝胶的综合性能,从而提高裂缝窜流的封堵效果。该过程的化学原理是层状微米级石墨粉的羟基和羧基能与聚丙烯酰胺分子链的酰胺基团发生物理化学相互作用。作为一种刚性结构,石墨粉可支撑原聚丙烯酰胺分子链的柔性骨架。通过刚柔结构的协同作用,新型凝胶的粘弹性、热稳定性、拉伸性能及封堵能力可显著增强。与单一丙烯酰胺凝胶相比,添加3000mg/L微米级石墨粉后,丙烯酰胺凝胶的弹性模量、粘性模量、相变温度、突破压力梯度、断裂伸长率及拉伸应力均大幅提高。在聚丙烯酰胺凝胶中添加石墨粉后,可有效封堵裂缝窜流。注水过程中,裂缝内的凝胶被突破时,网络状水流通道特征明显,注水突破压力高。实验结果为开发一种用于裂缝性低渗透油藏堵水的新型凝胶材料提供了尝试。