AI-Driven Synergistic Optimization of CO2-Associated Gas Injection and CCUS in Tight Oil Reservoirs

Tight reservoirs, characterized by extremely low porosity and permeability as well as restricted fluid mobility, have long faced challenges such as low recovery and high development difficulty. CO2-mixed associated gas drive has a broad application prospect, which acts in the function of an efficient development technology with both enhanced recovery and carbon sequestration capacity. The regulation of gas injection parameters involves the synergistic effect of multiple variables, but the traditional optimization methods have the problems of insufficient adaptability in the regulation of gas injection parameters and scheme design, which is difficult to meet the actual needs. This paper introduces artificial neural network and genetic algorithm to develop an intelligent optimization model, conducting research on residual distribution prediction, identification of controlling factors, optimization of gas injection timing, and the synergistic optimization of recovery and sequestration efficiency. The findings demonstrate that the residual oil in the target block is categorized into five types: imperfect residual oil in the well network, residual oil in the thin differential layer, residual oil masked by closed faults, residual oil not controlled by the well network, and residual oil controlled by sporadic sands. The interaction of gas injection rate and bottomhole flow pressure has a significant effect on both recovery and sequestration ratio. Among the factors, bottomhole flow pressure is the most important factor affecting the recovery, and gas injection rate is the crucial factor affecting the sequestration ratio. Reasonable timing of gas injection is the crucial factor in improving recovery. When the pressure depletion exceeds 70%, the wave volume decreases significantly, and gas should be injected in time to supplement the formation energy. At present, the study block has been depleted to 72.5%, which has entered the best time for gas injection. The synergistic optimized injection and production parameters are: gas injection rate of 9000 m3/d, permeability of 0.5×10−3μm2, and bottomhole flow pressure of 9.55 MPa. Under these conditions, the recovery is 39.66%, and the CO2 sequestration ratio is 27.26%. The research findings provide guidance for the efficient development of CO2 mixed associated gas drive in tight reservoirs.