The S reservoir in the X Oilfield in Iraq has great development potential due to its rich geological reserves. However, the low permeability and strong heterogeneity of the reservoir lead to great differences in reservoir stimulation performance. In this study, an integrated reservoir model and differential stimulation mode are put forward to solve the above problems. First, the feasibility of fracturing is evaluated by laboratory experiments. Second, an integrated reservoir model is established, which mainly includes a rock mechanics model, fracturing simulation model, and numerical simulation model, and correct the integrated model by fracturing operation curves and production dynamic curves. Third, three types of stimulation areas are classified according to the combination of sweet spot types, and three different stimulation modes are proposed. In conclusion, a small-scale stimulation mode should be applied in the Type I area to maximize economic benefits. In the Type II area, the medium-scale stimulation mode should be performed to ensure certain productivity while achieving certain economic benefits. In the Type III area, the large-scale stimulation mode should be employed to obtain certain productivity while economic benefits must be above a limit. The differential stimulation model proposed in this paper has made a great reference for the efficient development of low-permeability carbonate rocks.

Water alternating gas (WAG) flooding is a relatively mature technology for enhanced oil recovery (EOR). It combines the advantages of water flooding and gas flooding to maintain reservoir pressure and effectively mitigate the issues of high mobility ratio and fingering, demonstrating preferable application prospects. However, the evaluation of its development effect faces the challenges of complexity and lack of adaptability attributed to the multiple interactions of various factors involved in WAG flooding. Moreover, there are few studies evaluating the development effect of producers. Therefore, the traditional hierarchical analysis process (AHP) is improved in this study to fill the gap in this technological field. This process is combined with the entropy weight method (EWM) to establish a coupled evaluation model. Subsequently, this study classifies the contribution weights of producers and proposes adjustment suggestions for the primary development contradictions. This study finds that the contribution weight of producers to the well group indicates that the development effect of producers is no longer influenced by a single factor, but is determined by the coupling effect of geological, engineering, and development factors. By constructing a coupled model and fully utilizing on-site data to objectively characterize the underground production situation, the development effect of producers can be more accurately reflected. Finally, a closed-loop optimization system for evaluating the development effect and potential of producers with WAG flooding is established, laying a theoretical foundation for dynamic analysis and development adjustment of on-site engineers.