The minimum miscible pressure is one of the important parameters of CO2 injection in oil field. In order to determine the minimum miscible pressure between crude oil and CO2 in the tight reservoir of lucaogou formation, jimusar sag, Xinjiang, the laboratory slim tube test and interfacial tension test were carried out. The results show that the MMP measured by slim tube test in Xinjiang tight oil reservoir is 18.70 MPa, slightly higher than the MMP measured by the interfacial tension experiment, which is 18.44 MPa. The difference between the two is 1.4%, and both lower than the reservoir pressure of 43.00 MPa. Therefore, CO2 and crude oil can be miscible under the reservoir conditions. When the equilibrium pressure increases, the IFT decreased more as more CO2 dissolved in crude oil. When the system equilibrium pressure increased from 0.73 MPa to 28.46 MPa, the IFT value between crude oil and CO2 decreased from 22.62 mJ/m2 to 1.83 mJ/m2. When the equilibrium pressure was between 0.73 MPa to 13.33 MPa, the dissolution of CO2 in crude oil took the leading role. However, when the equilibrium pressure was between 15.84 MPa to 28.46 MPa, the extraction of light components in crude oil took the leading role, and the interaction mechanism between crude oil and CO2 changes from CO2 solubility to CO2 extraction of light components at the pressure of 13.67 MPa. Through the experimental study, the understanding of the MMP of the target reservoir and the microscopic interaction mechanism between crude oil and CO2 is deepened, which provided theoretical support for the formulation of CO2 injection development of the target reservoir.

The DEMATEL algorithm is an algorithm for analyzing the relationship between the influencing factors of complex systems. The algorithm has important application value for identifying the key factors of complex security system. First, on the basis of the DEMATEL algorithm, according to the knowledge of cognitive psychology and the status quo of the safety management of a gas station, the complex gas station safety system is divided into 4 subsystems, and further refined into 31 specific factors. Secondly, according to the DEMATEL algorithm, the MATLAB program is compiled to divide the cause factors and the result factors, and the influence degree, cause degree and center degree of each factor are calculated. Finally, the location of the key factors are displayed intuitively by drawing the cause results diagram. The results show that the information channel interruption, lack of recognition and information uncertainty, contingency plans and response defects are the key factors affecting the safety of gas stations. The longterm solution for gas station safety management is to control these 4 factors.