A dynamic maximum sealing pressure model for CO2 geological storage traps - ScienceDirect

A dynamic maximum sealing pressure model for CO2 geological storage traps

Author links open overlay panelMin Hao a b, Bing Bai a, Hongwu Lei a, Hengtao Yang a, Lu Shi a, Duoxing Yang c

Highlights

• Proposed a Maximum Sealing Pressure model for CO2 storage.

• Defines a practical “safety sealing pressure” and engineering workflow based on the short-board principle.

• Extends the model to assess containment potential of faulted caprocks, demonstrating wide applicability.

• Shows that limited CO2 invasion can enhance storage potential without compromising security.

Abstract

     Carbon dioxide (CO2) geological storage (CGS) is one of the key technologies for mitigating climate change and achieve carbon neutrality. Its long-term safety critically depends on the sealing capacity of subsurface trapping systems. Traditional site evaluations primarily rely on static indicators such as breakthrough pressure or fracture pressure, which cannot adequately capture the dynamic sealing behavior of caprocks under two-phase flow conditions, thereby limiting the full utilization of storage potential. This study proposes a novel Maximum Sealing Pressure () Model to characterize the dynamic sealing behavior during CO2 geological storage. Based on the Buckley–Leverett two-phase flow theory, the model incorporates parameters including caprock thickness, permeability, porosity, and relative permeability to establish a theoretical framework that accounts for both pressure diffusion and saturation-front propagation. The model defines the arrival of the saturation front at the top of the caprock as the critical breakthrough criterion, enabling a quantitative description of limited CO2 invasion and dynamic sealing mechanisms within the caprock. Furthermore, the concept of safety sealing pressure and an engineering evaluation framework based on the “short-board principle” are introduced, thereby bridging theoretical modeling and practical engineering design. Case study results demonstrate that the proposed model effectively captures the dynamic sealing potential and breakthrough risk of caprocks and can be further extended to evaluate the maximum sealing capacity of faulted caprock systems. This study provides a new theoretical framework for CO2 storage site selection, injection pressure optimization, and long-term safety design.