Analysis of the Mechanism of Fracture Propagation and the Influence of Engineering Parameters on CO ₂ Fracturing Effect in Shale Oil Reservoirs

The injection amount of CO 2 is a key parameter for the CO 2 fracturing effect of shale oil. In this paper, taking CO 2 fracturing in shale oil reservoirs as the research object, first, combining field tests and three‐dimensional well groups, the practical effects of CO 2 fracturing in shale oil reservoirs are analyzed. Second, a numerical model for CO 2 fracturing in shale oil reservoirs is established, and the effects of CO 2 consumption, soaking time on displacement efficiency, are analyzed. Third, the relationship between CO 2 intensity and cumulative oil production is compared and analyzed. Results show that: (a) Under different gas‐oil ratios, as CO 2 consumption increases, the replacement ratio also increases. (b) As the dissolved gas–oil ratio in the reservoir increases, the replacement ratio decreases under the same consumption, and the CO 2 ‐enhanced oil and reduced viscosity effect are covered by dissolved gas. (c) Under the conditions of a CO 2 consumption of 2 t/fracture and an oil–gas ratio of 0.2, after 30 days of soaking, the pressure enters the straight line segment, which is the reasonable time for soaking and the pressure to decrease in the straight line segment.