Study on the Mechanism of the Influence of Injection Medium and Gas Injection Method on the Recovery Rate of Fuman Oilfield in Tarim Basin

This study investigates the impact of different injection media and gas injection methods on oil recovery in the Fuman Oilfield within the Tarim Basin, aiming to optimize gas injection strategies for enhancing oil recovery in the Manshen 4 well area, known for its light, low‐viscosity, low‐sulfur volatile oil and stable strata thickness. The research employs experimental analyses to assess the miscible displacement characteristics of nitrogen, hydrocarbon gas, and carbon dioxide under varying pressures. Findings show that nitrogen achieves miscible displacement at higher pressures (47.5 and 45 MPa), whereas carbon dioxide has the lowest minimum miscibility pressure (MMP). Hydrocarbon gas shows miscibility at intermediate pressures (44 and 41 MPa). In the early stages of gas injection, nitrogen is most effective due to its ease of achieving miscibility. For later stages, hydrocarbon gas and carbon dioxide are more beneficial because of their enhanced solubility and miscibility with the volatile oil, leading to increased recovery rates. The study recommends a strategy combining top nitrogen injection–bottom water injection, and mid‐level oil production to maximize recovery efficiency and maintain optimal production levels. This study innovatively combines different gas injection media at different injection stages and proposes a top nitrogen injection–bottom water injection and mid‐level oil production strategy, which is a new attempt in enhancing oil recovery in similar volatile oil reservoirs. It provides a more comprehensive and efficient solution compared to previous single‐medium injection methods. These results offer valuable guidance for the Fuman Oilfield and similar geological settings.