Technical Report
The CO₂ Storage Resources Management System (SRMS) is a classification scheme to quantify, classify and categorise CO₂ storage resources. It comprises ‘total storage resources’, which are understood as maximum (theoretical) storage quantities that could ever be accommodated in the subsurface. Comprising maximum mobile CO₂ in structural/stratigraphic traps, maximum residually trapped CO₂ in other parts of the formation, and maximum dissolution potential in remaining formation water. ‘Storable quantities’ are understood as accessible from one or several current or future projects. It is the sum of capacity, contingent and prospective resources. The concept of ‘storage coefficient’ ‘E’ is the ratio of the subsurface volume of CO₂ storable quantities to either the total storage resources or the pore volume. The calculation is arguably complicated as E is impacted by lithological heterogeneity, trapping structures, boundary conditions, injection rates, well spacing, fluid properties etc. Due to its complexity, there is much controversy on how to estimate E, with some arguing it should not be used at all and that reservoir simulation is a better path. However, estimates for E are used in most regional mapping studies. This study explores storage resource classification schemes and their evolution in understanding, the calculation of storage resources and the storage co-efficient. This is explored in terms of calculating E for CO₂ storage sites, through flow modelling and analytical solutions.
