Experimental Study of Gas Drive Chemical Analysis and Enhanced Recovery in Tight Oil Reservoirs

As an important unconventional oil and gas resource, tight oil reservoirs are difficult to achieve ideal recovery rates with conventional oil recovery methods. In this paper, the oil driving effect of different gases (CO 2 and N 2 ) in tight reservoirs was investigated, and the auxiliary roles of chemicals such as surfactants and polymers in the gas driving process were also discussed. An autoclave was used for the different gas drive experiments, with a set pressure range of 10 MPa to 30 MPa, a constant temperature of 60°C, and the gas injection rate was adjusted to evaluate the drive effect. In addition, the effects of surfactants SDBS and C12-14 Pareth-7, as well as polymers PAM and HPAM at different concentrations on the gas drive effect were investigated. The results showed that the oil driving effect of CO 2 was better than that of N 2 , and the oil recovery of CO 2 drive was increased by more than 20% at 30 MPa and 20 mL/min. With the addition of surfactant, SDBS increased the recovery by 15% at 0.3% concentration, while PAM increased the recovery by 10% at 0.4% concentration. This study demonstrated the superiority of CO 2 gas drive in tight reservoirs and elucidated the enhancement effect of chemical adjuvants in the gas drive process by analyzing detailed experimental data. These findings provide an important theoretical basis and technical support for optimizing the gas-drive development scheme in tight reservoirs, which improves the crude oil recovery and has important practical application value.