In practical applications, the chemical and physical adsorption of a polymer solution greatly affects its action mode and effect. Understanding the adsorption mechanism and its influencing factors can help to optimize the application mode and ensure application efficiency. Three types of polymer solutions—partially hydrolyzed polyacrylamide (HPAM), hydrophobically associating polymer (AP-P4), and dendrimer hydrophobically associating polymer (DHAP), which are viscoelastic liquids—were used as sorbates to study their adsorption by a sorbent such as quartz sand. The effects of the solution concentration, contact time, particle size of quartz sand, solid–liquid ratio, and fluid movement on the adsorption capacity of the polymer solutions were examined. The results showed that HPAM presents a typical Langmuir monolayer adsorption characteristic, and its adsorption capacity (per unit area) is 1.17–1.62 μg/cm². The association enhances the interactions of the AP-P4 and DHAP solutions, and they present multilayer characteristics of first-order chemical adsorption and secondary physical molecule adsorption. Moreover, the dendrite structure further increases the adsorption thickness of DHAP. Hence, the adsorption thicknesses of AP-P4 and DHAP are four and six times that of HPAM, respectively. The adsorption of the three polymers is consistent with the influence of fluid motion and decreases with increasing fluid velocity. However, the larger the thickness of the adsorption layer, the clearer the influence of the flow, and the higher the decrease in adsorption capacity. Optimizing the injection rate is an effective method to control the applications of a polymer in porous media.

Due to low oil recovery factor in heavy oil reservoir, air injection with catalyst becomes a competitive technology to effectively reduce viscosity of crude oil as a result of the low cost and small environment pollution. This paper determined the feasibility of air injection with catalyst in a heavy oil reservoir through static and dynamic experiments. The results indicated that under the effect of catalyst, oxidation between heavy oil and air could significantly reduce the viscosity of crude oil. The optimal catalyst contained 0.7 wt. % oil-solubility organic acid copper and 0.5 wt. % sodium hydroxide. With the oxidation time increasing, viscosity of crude oil decreased and oil recovery factor increased. With temperature increasing, viscosity of crude oil decreased sharply and oil recovery factor increased. The oil recovery factor of air huff-n-puff process was 30.2%. Air injection with catalyst in the reservoir is a promising technology.

Air injection oil displacement is a highly promising enhanced oil recovery technology due to its wide gas source availability, low cost and strong reservoir adaptability. To enhance the application effectiveness of air injection for low-temperature oxidation (LTO) flooding in a specific light oil reservoir in China’s Xinjiang oilfield, this study systematically investigates the static oxidation characteristics of crude oil and their influence on oil displacement performance. High-pressure static oxidation experiments and long-core physical simulation tests were conducted to examine the effects of oxidation time, water saturation, oxygen concentration, medium oil components (C₇–C₁₇), and reservoir minerals on the LTO behavior of crude oil. The oil displacement efficiency under different permeability conditions during air flooding was also analyzed. The results indicate that the LTO process exhibits stage-wise characteristics: in the initial stage, oxygen consumption is rapid, light and medium components decrease while heavy components increase, leading to higher viscosity and density of the crude oil. Reservoir conditions significantly influence oxidation pathways—high water saturation, low oxygen concentration, and high medium components inhibit oxidation, whereas reservoir cuttings promote cracking reactions due to their catalytic effect, resulting in oil lightening. Long-core flooding experiments further reveal that air flooding is more suitable for formations with relatively high permeability, which helps delay gas channeling, improve sweep efficiency, and thus achieve higher oil recovery. This research clarifies the intrinsic relationship between oxidation reactions and oil displacement performance during air injection, providing a theoretical basis for the application of air injection technology in light oil reservoirs.

The paper investigates a family of robust reinsurance-investment strategies under relative performance criteria for the insurers who have exponential utility and trade in a common reinsurance-investment horizon in log-normal markets. Assume that two correlated Brownian motions used to characterize the insurance surplus risk and stock price risk. By applying stochastic control theories, we derive the closed-form solutions for the n-players game and the corresponding mean field game, furthermore the equilibria strategies are shown to be unique in the class of constant equilibria. Finally, we present the influence of model parameters on reinsurance and investment strategies with economic explanations by some numerical figures.