This study presents Phase 11 of a unified dynamic multiphase model describing subsurface fluid systems, focusing on space formation as the development of reservoir volume. This phase defines the processes through which pore space is created and expanded, enabling fluid accumulation and storage. Following fluid–rock interaction in earlier phases, the subsurface undergoes structural modifications that lead to pore enlargement, fracture development, and the formation of dissolution cavities, particularly in carbonate systems. These processes increase porosity and create interconnected void networks capable of storing fluids. In carbonate formations, space formation may result in vugs, cavities, and highly connected pore systems, while in sandstones it may involve cement dissolution and improved pore connectivity. These changes transform the rock from a relatively solid medium into a functional storage system. The process is described through porosity evolution over time and its relationship with storage capacity, where the total volume available for fluid accumulation depends on both porosity and rock volume. Increasing porosity also enhances permeability and supports continued fluid movement into newly formed storage spaces. This phase marks the transition from reservoir initiation to reservoir development, establishing the physical capacity required for accumulation. It introduces a dynamic perspective in which reservoir space is actively generated rather than passively inherited, providing a framework for understanding variability in storage capacity and reservoir quality. This publication is part of the research series: “A Dynamic Multiphase Model for Hydrocarbon and Hydrothermal Systems” It represents Phase 11 in a structured 13-phase framework describing the evolution of subsurface fluid systems from deep energy generation to accumulation. This phase defines the development of storage capacity, transforming the subsurface into a functional reservoir through dynamic porosity and volume creation.
Kujtim gjoka Gjoka (Fri,) studied this question.