功能化部分水解聚丙烯酰胺的性能及提高采收率研究OA

Partially hydrolyzed polyacrylamide(HPAM)used in chemical flooding has poor temperature and salt resistance,insufficient viscosity stability,and loss of oil displacement efficiency due to self-polymerization deposition.To address this issue,the size effect and unique interface characteristics of nanomaterials were combined with traditional polymers,and the drawbacks of polymer flooding can be overcome,thereby enhancing the oil displacement performance of polymer-based fluid flooding.This paper used the low-cost citric acid and urea as raw materials and leveraged their abundant hydrophilic groups and nucleophilic heteroatoms to prevent the curling of HPAM molecular chains through hydrogen bonding,thereby stabilizing its linear structure.Additionally,the water-soluble zinc chloride was combining with the carboxyl groups of HPAM creating steric hindrance,while the cationic nature of zinc ions enhanced the salt tolerance of HPAM.By using a one-step hydrothermal method,the raw materials underwent carbonization treatment to form a nano-modifier.Then,through the physical action of electrostatic neutralization,the nano-modifier was combined with the HPAM molecules to obtain the modified HPAM.The results show that,compared with the unmodified HPAM,when the mineralization degree is 1×104 mg/L,the viscosity retention rate of the modified HPAM with a mass fraction of 0.5%increases by 54%at a shear rate of 0.1-100 s-1,and the viscosity retention rate increases by 26%.The oil-water interfacial tension is reduced to as low as 0.16 mN/m.By changing the wetting angle of the core and crude oil from a neutral wetting angle of 97° to a hydrophilic wetting angle of 34°,the oil repellency of the rock was significantly enhanced;under different polymer concentrations,core permeability,and oil type conditions,the modified HPAM flooding achieved a further increase in crude oil recovery rate of 7.36%-8.98%compared to the unmodified HPAM flooding.The modified HPAM system not only overcame its inherent deficiencies but also significantly improved the viscosity of polymer solution,oil-water interfacial tension,and rock wettability,promoting the innovation and development of polymer flooding-based oil recovery technology.