Natural gas storage is required primarily to meet seasonal load variations and to improve the resilience and cost effectiveness of energy infrastructure. With the decline in indigenous gas supplies and increasing demand there is a need for increased storage capacity to ensure the security of gas supplies. Quintessa is supporting both regulators and operators in this endeavour through technical services relating to the assessment of reservoir integrity.
Quintessa collaborated with the British Geological Survey (BGS) in undertaking a project for the Health and Safety Executive (HSE) to examine the potential for leakage of natural gas from Underground Gas Storage (UGS) in salt caverns and depleted oil/gas reservoirs. Leakage scenarios were developed and scoping calculations carried out to evaluate the likely significance of any leakage. A database of Features, Events and Processes (FEPs) was used to audit the issues identified by the BGS as potentially influencing whether or not gas leakage will occur. Three basic scenarios were identified as relevant to existing or potential onshore UGS facilities in the UK. For each scenario, scoping calculations were carried out to evaluate limiting gas fluxes and surface emission areas. The BGS component of the work is reported in HSE RR605, which provides context, background and data for the work reported by Quintessa in HSE RR606. Quintessa has subsequently provided support to UGS developers to assess site-specific leakage risks.
More recently, Quintessa developed a risk assessment methodology for geoenergy technologies, which was applied to assess the risks of underground coal gasification (UCG) in a hypothetical site. The flexible risk assessment methodology that Quintessa developed can be applied at any stage in a geoenergy project, between initial planning and final site abandonment.
Quintessa’s expertise on gas storage, including methane and hydrogen storage, draws on its wider experience of underground storage of carbon dioxide, hazardous waste and radioactive wastes. In particular, the highly developed risk assessment and performance assessment methodologies used in these related areas are directly applicable to gas storage. One example of this is Quintessa’s development and maintenance of an online database of Features, Events and Processes of potential importance to CO2 geological storage.
Quintessa has also supported the HyStorPor project via the industrial advisory board role to help investigate the fundamental questions of what happens when hydrogen is being injected and withdrawn from subsurface reservoirs.