Analytical and Numerical Investigation of Spontaneous Imbibition: A Sensitivity Analysis on the Effect of Rock Properties and Boundary Conditions
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In this research we present a numerical substitute for laboratory experiments through simulating a core sample fully bounded by the wetting phase to represent cocurrent and countercurrent spontaneous imbibition (SI) processes. We combine the results of the simulations with the analytical model for co-current and counter-current spontaneous imbibition developed by Karen Schmid in her 2011 study to validate the upscaling of laboratory experiments to field dimensions using dimensionless time. We then present a detailed parametric study on the effect of boundary conditions and characteristic length to compare imbibition assisted oil recovery with different types of boundary conditions. We demonstrate that oil recovery was the fastest and highest when all faces are open to flow. We also demonstrate that all cases scale with the nondimensionless time presented by Karen Schmid and Sebastian Geiger, and show a close match to the numerical simulation and the analytical solution. Furthermore, the effects of the variations in the rock and fluid properties on the scaling group is studied in detail. We notice that the variations in different parameters including initial water saturation, oil/water viscosity ratios, oil/water relative permeability and wettability of the studied core did not affect the quality of the scaling of Karen Schmid and Sebastian Geiger’s group, and the results matched accurately with the analytical solutions suggested., Moreover, we discuss how the effect of constructing a model with varying grid sizes and dimensions affects the accuracy of the results. We compare the results of the 2-D and 3-D models to observe that 3-D model proved superior in the accuracy of the results on the expense of the CPU time to simulate a simple counter-current SI. Thus, we deduce that 2-D models yield satisfying results in a timely manner compared to 3-D models which are time-consuming. Our work concluded that the new definition of non-dimensionless time work well with co-current and counter-current SI cases regardless of the boundary condition imposed on the core. Also, the study showed that the characteristic length used impacts directly the degree of correlation obtained, imminently improving the upscaling technique.
Abd, Abdul Salam (2018). Analytical and Numerical Investigation of Spontaneous Imbibition: A Sensitivity Analysis on the Effect of Rock Properties and Boundary Conditions. Master's thesis, Texas A & M University. Available electronically from