Capillary Breakthrough Pressure Measurement of Hydrogen and Development of a Laboratory Protocol

This thesis addresses the critical challenge of secure and efficient underground hydrogen storage (UHS), a key component in the global transition to clean energy and the achievement of carbon neutrality goals under the Paris Agreement. Hydrogen, as a zero-emission energy carrier, holds vast potential across multiple sectors; however, its small molecular size and high diffusivity pose significant leakage risks during storage. Ensuring the integrity of caprocks that seal underground reservoirs is therefore essential. The core focus of this research is the assessment of experimental methods dedicated to evaluating caprock sealing efficiency through representative measurement of capillary threshold pressure a fundamental parameter that determines a caprock’s hydraulic ability to prevent hydrogen migration. A comprehensive review of existing laboratory methods was conducted, with emphasis on the most widely adopted practices for experimentally evaluating different types of threshold pressure. Building on this foundation, a standardized laboratory protocol was developed and implemented using a customized experimental setup capable of measuring breakthrough pressure for hydrogen as well as other gases such as CO₂, CH₄ and N₂. The laboratory system components were described. Based on which, the adopted breakthrough pressure measurement protocol, namely step-by-step test, was outlined. To this end, targeted technical recommendations are proposed to enhance measurement reliability and repeatability, including improvements in temperature control, pressure stability and system automation. The developed protocol provides a robust, repeatable and accurate methodology for assessing caprock sealing efficiency, which is important for selecting suitable UHS sites, defining maximum operational pressures and minimizing storage-related risks. The outcomes of this work contribute significantly to advancing safe and efficient UHS technologies, supporting the broader deployment of hydrogen as a clean energy solution and facilitating sustainable energy transition.