Enhancing structural strength and water retention of crosslinked polyacrylamide gel with the T-ZnOw

• Published in: Fuel (Guildford) 2024-12, Vol.377, p.132838, Article 132838
• Main Authors: Zou, Chenwei, Liu, Yifei, Yang, Ning, Luo, Quanmin, Mao, Chengwei, Wu, Yining, Dai, Caili
• Format: Article
• Language: English
• Subjects: Nano composites; Polymer gel; Structural stability; Thermal properties; Water retentivity
• ISSN: 0016-2361
• DOI: 10.1016/j.fuel.2024.132838

[Display omitted] •T-ZnOw enhances gel strength and water retention for high-temperature reservoirs.•T-ZnOw reinforces gel network, forming a tighter structure with polymer chains.•T-ZnOw addition increases bound water content and improving thermal stability.•Nanocomposite gel shows promise in EOR, CO2 storage, and geothermal development. Crosslinked polyacrylamide gel serves as an effective plugging material, crucial for preventing water/gas channeling in reservoirs and enhancing the swept volume and oil recovery. However, its practical application encounters a significant challenge in maintaining long-term stability of strength and volume, particularly under high temperatures. This study investigates the reinforcement of polyacrylamide gel with three-dimensional (3D) nanomaterials, specifically tetra-needle-like zinc oxide whiskers (T-ZnOw), to enhance its structural stability and bound water content. The stress sweep tests showed that the addition of 0.15 wt% T-ZnOw increased the maximum elastic modulus of the gel to 28.5 Pa, representing a 51.2 % improvement compared to before the addition. After 60 days of high-temperature aging at 130 °C, the T-ZnOw strengthened gel still maintained an elastic modulus of 21.8 Pa. With increasing T-ZnOw concentration, the yield point of the gel increased from 4.74 Pa to 9.57 Pa, the anti-deformation of the gel has significantly increased. The stability test results in high salinity water indicate that at a salinity of 150,000 mg/L, the dehydration rate of the strengthened gel is less than 5 %, with an elastic modulus retention rate exceeding 88 %. Furthermore, thermodynamic testing confirms the enhanced thermal degradation resistance and water retention capacity of the gel. Under reservoir temperature conditions, the T-ZnOw strengthened gel exhibits a weight loss of less than 3 %. Additionally, the inclusion of T-ZnOw results in an increase in the bound water capacity index from 4.65 to 12.28. In conclusion, the integration of T-ZnOw into the polyacrylamide gel network not only enhances its mechanical performance and water retention under high-temperature conditions but also demonstrates superior stability in high-salinity environments. This innovative material shows significant potential for improving oil recovery rates in high-temperature reservoirs and can be applied to other high-temperature underground scenarios such as geothermal development and CO2 utilization and storage.