Research on the Mechanism of Electrical Resistance Changes in CO2 Utilization and Storage Processes

CO ₂ flooding is one of the main methods to improve oil recovery in reservoirs, while also achieving the storage and utilization of carbon dioxide. By measuring the changes in resistivity during CO ₂ flooding, the changes in oil saturation in the reservoir can be determined, thereby guiding CO ₂ flooding development. In order to clarify the factors that affect the changes in resistivity during CO ₂ flooding and the patterns of resistivity changes, hollow conductors were used as rock cores to avoid the influence of geological factors. Experiments were conducted to measure resistivity during the displacement process of different fluids (deionized water, formation water, supersaturated CO ₂ deionized water, supersaturated CO ₂ formation water) at different temperatures and pressures, in order to clarify the experimental conditions and the influence of the fluid itself on resistivity. The experimental results indicate that temperature, pressure, mineralization degree, and CO ₂ content all affect the magnitude of electrical resistivity. The higher the temperature, the lower the resistivity; The higher the pressure, the lower the resistivity; The higher the mineralization degree, the lower the resistivity; The higher the CO ₂ content, the lower the electrical resistivity. This study reveals the reasons for the changes in resistivity during the development process, providing a reference for determining the distribution of oil-water areas in target reservoirs using the average resistivity change size, and providing a theoretical basis for calculating the remaining reserves of the reservoir and adjusting the plan on site in the future.