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It has been proved that the general performance of aviation fuels can be improved with the addition of biofuels. To understand the fundamental physical properties of the blends, n-undecane, methyl decanoate, and n-butanol were chosen as model compounds to construct a mixed system. Densities (ρ) and viscosities (η) of the ternary system n-undecane + methyl decanoate + n-butanol and its corresponding binary systems n-undecane + methyl decanoate, n-undecane + n-butanol, and methyl decanoate + n-butanol were measured at different temperatures T = (293.15–333.15 K) and atmospheric pressure p = 0.1 MPa. The excess molar volumes (V m E) and the viscosity deviations (Δη) of the binary systems and the ternary system were correlated to the Redlich–Kister equation and four semi-empirical equations, respectively. The V m E values of the ternary system and binary systems are all positive over the entire concentration range at each experimental temperature, while their Δη values are all negative. The experimental results can provide reliable data for the compatibility of biofuels and fossil fuels.

In this study, the effect of fracturing fluid on the permeability of tight oil reservoirs is analyzed through oil absorption. The mechanism of permeation and absorption in tight oil reservoirs was studied using the molecular dynamics simulation of fluid flow through fractures in porous media containing crude oil. The influence of surfactants on the adsorption characteristics of crude oil formations on rock walls was also examined. The research results show that the introduction of the appropriate surfactant to the fracturing fluid could accelerate the rate of percolation and recovery as well as improve the recovery rate of absorption. The optimal concentration of polyoxyethylene octyl phenol ether-10 (OP-10) surfactant in the fracturing fluid was 0.9%. When the percolation reached a certain stage, the capillary forces in the crude oil and percolation medium in the pore stabilized; accordingly, the crude oil from the pore roar should be discharged at the earliest. The fluid flow through the fracture effectively carries the oil seeping out near the fractured wall to avoid the stability of the seepage and absorption systems. The surfactant can change the rock absorbability for crude oil, the result of which is that the percolating liquid can adsorb on the rock wall, thus improving the discharge of crude oil. The results of this study are anticipated to significantly contribute to the advancement of oil and gas recovery from tight oil reservoirs.