Research on Profile Control Potential Evaluation and Optimization Design Technology in Block M of Gudong Oilfield

After long-term water injection development in Block M of the Gudong Oilfield, the fluid seepage field in the formation has become increasingly complex, and the heterogeneity of the reservoir has intensified. The uneven injection-production and the differences in lithological permeability have further led to a series of problems such as uneven reserve utilization, a low injection-production correspondence rate, and a poor overall development effect. During the development process, severe water flooding at the bottom and rich remaining oil at the top within the layer also emerged. These issues not only affected the economic benefits of the oilfield but also put forward higher requirements for the subsequent development strategies. In order to solve the above problems, based on a detailed analysis of geological characteristics, reservoir engineering and monitoring data, this paper uses the numerical simulation method to systematically simulate the dynamic changes in the residual oil saturation and pressure field in the formation under different development stages. The simulation results show that the pressure and saturation in each layer are both on a downward trend, especially in the layers with large pressure changes, where the oil saturation changes are more significant. Therefore, combined with the results of numerical simulation, a series of profile control and water shutoff schemes were systematically designed. These schemes covered different types of profile control agents and technological parameters. Representative well groups were selected to predict and evaluate the profile control effect. In the technical and economic evaluation of the profile control effect, the input–output ratio method was adopted. Finally, an optimal scheme was selected and applied in the field. The results show that after the implementation of this scheme, the daily oil increment of the well group was remarkable. During the test period, the cumulative oil increment reached 100 t, and the total expected oil increment could reach 190 t. The input–output ratio reached 1:2.1. The profile control measures significantly improved the injection-production correspondence, slowed down the in-layer water flooding, and further enhanced the recovery rate of remaining oil. In conclusion, the methods and achievements of this study can provide important technical references and support for the efficient and long-term development of similar high-water-cut and heterogeneous complex oil reservoirs, and have guiding significance for the subsequent adjustment, potential tapping, stable production and efficiency improvement of oilfields.