Optimization of Well Parameters for Oil and Gas Production from Bottom Water Reservoir with Low-Permeable Interlayer

In recent years, the development of bottom water reservoirs has received significant global attention due to its large reserves. However, the presence of low-permeability interlayers can significantly impede the seepage of injected water, thereby constraining hydrocarbon recovery and economic viability in this region. To address this issue, this study quantifies the impact of reservoir properties and well parameters on the production dynamics of bottom-water reservoirs with low-permeability interlayers. Subsequently, Particle Swarm Optimization (PSO) is coupled with numerical simulation to optimize key well parameters, including well placement, well constraints, and injection modes. The results demonstrate that the sensitivity of cumulative oil, gas, and water production varies significantly with different injection modes, and initial oil saturation and permeability are the most influential factors. Additionally, horizontal injection mode can effectively ameliorate bottom water coning compared to vertical injection mode. Furthermore, the optimization results quantitatively validate the superiority of horizontal injectors over vertical injectors in terms of both economic feasibility and hydrocarbon recovery. In the scenario of horizontal injection mode, optimization leads to 2.34 times increase in net present value (NPV), whereas vertical injectors exhibit comparatively smaller gains, with 1.35 times increase in NPV. Moreover, the results indicate that gravity influences downward water flow, limiting the swept area in the upper part of the bottom-water reservoir. Importantly, a comparison between the optimized NPV in this study and that in previous research reveals that the presence of a low-permeability interlayer can significantly reduce the economic benefits of bottom-water reservoirs. The findings of this work provide some insights into the development of oil and gas production from bottom water reservoirs and the optimization of well parameters.