Three-Dimensional Physical Simulation Experiment on the Development Adjustment of Reservoirs with Gas Cap and Edge Water in Middle and Late Stage Reservoirs

In the middle and late stages of natural energy development, reservoirs with gas cap and edge water are affected by gas channeling and intensified water coning, and the formation pressure drops rapidly. The production declines greatly, and production conditions deteriorate sharply. In order to explore the development adjustment direction of this type of reservoir in the middle and late stages, a large-scale three-dimensional physical model of the reservoir with a gas cap and edge water was designed based on the similarity theory by taking an offshore reservoir with large gas cap and middle edge water as the prototype. Three development adjustment methods and potential tapping effects were studied, namely, continued natural energy development, barrier water injection development, and sidetracking of old wells towards high locations. The experimental results show that the natural energy development of reservoirs with gas cap and edge water is dominated by gas cap energy and affected by gas channeling in the high-permeability layer. Oil enrichment occurs in the upper part of horizontal wells in reservoirs with medium and low permeability, which is the direction for subsequent potential investigation. The barrier water injection can effectively suppress the gas channeling of the gas cap in high-permeability layers and has a significant effect on increasing and stabilizing production in low-permeability layers. The sidetracking of old wells is more effective in improving oil recovery in reservoirs with a high proportion of medium-permeability layers. One old well underwent sidetracking towards higher locations, achieving good on-site application results. The research result can provide a reference for improving adjustment effect of multiple methods to enhance oil recovery.