Study of unsteady state flow in a deformable formation under two-phase flow condition

The article addresses the issue of identifying relative phase permeabilities, taking into account the variation of parameters characterizing the environment and fluid during the development of a multi-layered formation, depending on the drop in reservoir pressure. The algorithm was implemented using software based on the gradient method of optimal control theory, and the dynamics of output indicators were analyzed across a wide range of adjustable parameters. Additionally, an efficient methodology was developed to refine the relative permeability function based on phase saturation, during which the hydrodynamic model was calibrated to match actual well data. In a specific field case, the potential and evaluation of converting several oil wells into water injection wells, thereby increasing the overall oil production of the field, was demonstrated. To accomplish this, the hydrodynamic problem for two-phase flow was replaced with a three-phase flow problem. The task of forecasting oil recovery based on the identified relative phase permeabilities was solved using the Nexus Black Oil simulation software package. The practical research conducted involved analyzing a specific field. The solution was executed using a specialized software algorithm. The computer modeling of the fluid filtration process during field development allows for the analysis of performance dynamics across extensive variations. The experimental functional dependencies, which characterize the variation of the physical parameters of the formation and fluid with respect to pressure, are based on data presented in the reference literature. Keywords: fluid; reservoir; deformable porous medium; multi-layer deposit; pressure; hydrodynamic model adaptation; history matching.