This study presents Phase 3 of a unified dynamic multiphase model describing subsurface fluid systems, focusing on the role of layered geological structures in controlling fluid flow. A layered geological system consists of multiple superimposed strata with distinct lithological properties, including variations in permeability, porosity, and mechanical and chemical behavior. In natural subsurface environments, these layers form a heterogeneous medium that actively governs fluid migration. Each layer may function as a conduit, barrier, or transformation zone, influencing the direction, velocity, and composition of migrating fluids. As a result, fluid migration is not solely controlled by pressure gradients but is strongly regulated by stratified geological architecture. The flow system is therefore stratified and non-linear: fluids accelerate in high-permeability layers, slow down or stop in low-permeability layers, and undergo compositional changes through interaction with reactive lithologies. This behavior is described mathematically through layer-specific flow equations (qᵢ = -kᵢ/μ ∇P), effective flow summation across layers, and cumulative resistance to vertical flow. The phase is integrated into the global model through layer-dependent parameters, including Λᵢ = Pflow / Pc, i, linking local geological resistance to overall system dynamics. This phase establishes lithology as a primary control on fluid behavior, transforming the subsurface from a passive medium into an active, structured system that governs flow pathways, heterogeneity, and reservoir formation. This publication is part of the research series: “A Dynamic Multiphase Model for Hydrocarbon and Hydrothermal Systems” It represents Phase 3 in a structured 13-phase framework describing the evolution of subsurface fluid systems from deep energy generation to accumulation. This phase defines how stratified geological structures control fluid pathways and behavior, linking pressure-driven migration to lithological heterogeneity.
Kujtim gjoka Gjoka (Fri,) studied this question.