Taking a heavy oil in Shengli Oil Field as the research object,the core was filled with porous medium in the core displacement instrument to simulate the formation conditions,and the aquathermolysis of heavy oil under different reaction conditions was studied.The results shown that the viscosity reduction rate of heavy oil can reach 20.8% only in porous medium by direct displacement,and the viscosity reduction effect is more obvious in porous medium system after the addition of amphiphilic catalyst for reaction.The displacement viscosity reduction rate after reaction in a low?temperature environment of 65 ℃ is 57.9%.However,the reaction in a low?temperature environment leads to an increase in the molecular weight of the asphaltene component,with the relative molecular weight of the asphaltene increasing from 5 244 g/mol to 6 690 g/mol.After the reaction is completed and maintained in a high?temperature environment of 265 ℃,the displacement has a better viscosity reduction effect,with a maximum comprehensive viscosity reduction rate of 96.0%.It provides an important guiding significance for the optimization of operating conditions of heavy oil aquathermolysis in the field application process.

In order to explore the best extraction technology of flavonoids from Maoyanberry tea, the extraction conditions of flavonoids from Maoyanberry tea were optimized by using the method of single factor and response surface. The results showed that the optimal extraction conditions were as follows: Ethanol volume fraction 80%, liquid?solid ratio 25 mL/g, water bath temperature 85 ℃, water bath time 40 min. Under these conditions, the yield of flavonoids was 162.72 mg/g, which was close to the predicted value of the model, indicating that the optimized method was reasonable and feasible.

Combined with SEM, EDS, dynamic evaluation of plug formation, microscopic visualization and long core displacement experiments, the damage mechanism of residual acid in polymer injection oilfield to the reservoir was studied. The results show that the damage of residual acid to the reservoir is mainly due to the crosslinking point of the polymer molecular chain with high valence cations such as Al³⁺ and Fe³⁺ in residual acid. The crosslinking network elastic colloid is formed by the coordination between carboxylic acid radicals in the polymer side group and high valence cations, and the degree of crosslinking increases with the increase of ion concentration. The elastic colloid formed blocked at the edge and pit of the pore throat, which makes the pore throat diameter gradually smaller. In the process of flow, it wraps around the formation particles and carbonate sediments, forming a composite blockage micelle, resulting in deep plugging. The long core displacement experiment shows that residual acid can damage the core up to 60%. The research results provide a theoretical basis for the research and development of plugging removal fluid system and optimization of plug removal processes in polymer injection oilfield