Journal of Energy Engineering

As an emerging energy demand owing to growth in industries and population, understanding hot water injection for the production performance in heterogeneous reservoirs becomes highly essential. The present investigation provides insights into the influence of reservoir rhythm and American Petroleum Institute (API) gravity on hot water flooding. A sensitive study on the order of permeability variation is also performed to understand the extent of hot water flooding. With this intent, we developed an improved fully coupled energy and multiphase flow model associated with the evolution of fluid and rock properties in two-dimensional reservoirs to evaluate hot water flooding scenarios. The lithological heterogeneity of the reservoirs degraded the total oil production rate in contrast to the homogeneous reservoir. Random rhythm reservoir effectively increases the total oil production and is observed to have a cumulative oil production of $338.62{\mathrm{m}}^3$, which is the highest among other rhythmic reservoirs. Waterfront advancement has reduced in higher API gravity reservoirs; however, more effective oil displacement than lower API gravity reservoirs is experienced, reducing the early water breakthrough phenomenon and increasing the total oil production. The largest cumulative oil production of $348.86{\mathrm{m}}^3$ is observed in the 21° API gravity oil reservoir. The wider variation of the permeability in the reservoir reduced the oil production significantly. The lowest cumulative oil production of $248.66{\mathrm{m}}^3$ is observed in the 2nd order reservoir in contrast to the reservoir, possessing permeability variation by scale factor and 1st order. From the present investigation, it can be interpreted that the lithological heterogeneity can influence the performance of hot water flooding by reducing 5.82%, 6.69%, 7.13%, and 7.91% in random rhythm, compound rhythm, negative rhythm, and positive rhythm reservoir in comparison to the homogeneous reservoir, which is required to design properly to reduce the drastic impacts on the hot water flooding project.

This study investigates the impact of nonuniform assembly forces on the mass transfer characteristics of the proton exchange membrane fuel cell. Initially, utilizing a solid mechanics model, the influence of assembly forces on gas diffusion layer (GDL) material properties, including porosity, permeability, and diffusion coefficients, is explored. Under a 2 MPa assembly force, the strain distribution in the GDL exhibits a symmetric structure, with maximum strain occurring below the rib, reaching $66\mathrm{\mu m}$. This indicates that assembly forces alter the GDL structure, affecting mass transfer characteristics. Comparing material properties under varying assembly forces reveals that, with increasing strain, porosity and permeability gradually decrease while diffusion coefficients increase. This variation positively impacts activation and concentration polarization, particularly enhancing the removal of liquid water. Additionally, the study investigates the effects of different forms of nonuniform assembly forces, such as incremental and decremental forces. Experimental validation confirms the optimization effects of a 2–1.5 MPa decremental assembly force on fuel-cell performance, including enhanced mass transfer rates and reduced ohmic and concentration polarization. This research provides novel insights for fuel-cell design, aiming to improve mass transfer characteristics and overall performance.