Compared with conventional HPAM, Sodium Methallyl Sulfonate (SMAS) based polymers own firmer molecular skeleton, stronger charge anti-shielding capacity and better hydration stability. They effectively avoid high-temperature hydrolysis degradation and high-salinity chain curling, thus achieving remarkably higher viscosity retention rate in ultra-high temperature and high-salinity oil reservoirs.
- Superior thermal structural stabilityConventional HPAM is prone to thermal degradation and amide group hydrolysis under ultra-high temperature, leading to severe molecular chain fracture and sharp viscosity decline. The rigid branched structure of Sodium Methallyl Sulfonate (SMAS) strengthens the main chain skeleton, effectively resisting high-temperature thermal aging and slowing down molecular degradation.
- Strong anti-ion shielding performanceMassive inorganic ions in high-salinity formation water easily shield the negative charges on HPAM molecular chains, causing severe chain curling, shrinkage and rapid viscosity loss. The highly polar sulfonate groups carried by SMAS have strong anti-shielding ability, which can maintain the extended state of molecular chains steadily without obvious crimping.
- Excellent salt tolerance and anti-salting-out propertySMAS functional groups form stable hydration shells around polymer molecules, which can effectively resist salting-out effect under extreme high salinity. By contrast, HPAM is highly sensitive to high-valent cations such as calcium and magnesium, and is easy to aggregate and precipitate to lose viscosity.
- Weak hydrolysis tendency under harsh conditionsHPAM will continuously hydrolyze in long-term high-temperature water environment, resulting in uneven molecular structure and further attenuation of solution viscosity. SMAS-modified copolymer has low hydrolysis activity, stable chemical properties and stable viscosity performance in long-term reservoir seepage environment.
- Outstanding shear resistance synergizes viscosity maintenanceSMAS introduces steric hindrance structure to enhance the overall rigidity of the polymer. It is less vulnerable to shear damage during injection and stratum migration, and can still maintain good hydrodynamic size and effective viscosity, further raising the final viscosity retention rate.
