UPSTREAM EP ADVISORS
Where Technical Insight Meet Business Solutions
Storage Capacity Calculator
You can use our basic calculator for calculating CO2 storage volume for initial site screening. Please note that calculator is just for the screening purposes only, to have an idea on how much CO2 your project site can store during lifecycle injection. A well planned Well-testing (click) can help collect the data and perform analysis to estimate capacity, injectivity and containment.
The slide below provides the technical basis of storage capacity calculations and data required. Displacement efficiency (ED), among other variables is a big uncertainty. We can provide analogue data (ED) for screening without acquiring expensive SCAL data.
A storage operator is planning to capture and store 1.0 mtpa (million tonne per annum) of CO2 in Saline Aquifer for 20 years. They selected area has some 2-D seismic lines and offset well data. They want to screen the site to see if it suitable and can store the project volume?
Aquifer Depth = 5000 ft (offset well & Seismic data)
Aquifer Temperature = 80 0C / 176 0F (offset well)
Aquifer pressure. = 13 MPa /1885 psi (offset well)
CO2 Density = 400 kG/m3 (estimated from reservoir T & P)
Aquifer Thickness. = 70 ft from offset well logs)
Aquifer Porosity. = 25 % (from offset well logs)
Aquifer Area = 20,000 acres (Seismic data)
Total project Storage volume required = 1.0 mtpa * 20 (years) = 20 Million Tonnes (MT)
Geologist indicated that sand is clean and NTG ~ 95%.
The regional seal is thick and extensive
Effective porosity is equal to total porosity
The storage depth (5000 ft) is below 800 m & salinity (> 10,000 mg/l) i.e. safely below USDW (US Drinking Water) Aquifers.
Storage temperature meets supercritical conditions for CO2
Reservoir Engineers indicate ED ~ 50% from analogue data
MassCO2 (MM Tonne) = 1.236 * 20,000 * 70 * 0.25 * 400 * (0.5) *(1.0 * 0.95 *1.0) =
MassCO2 (MM Tonne) ~ 82 MT
So initial site screening indicates that the site is suitable because:
Site has adequate capacity (i.e. 82.0 MT) for CO2 storage to store the project volume ( 20.0 MT). So this site will be selected for further evaluation.
The storage capacity of aquifer can be further refined. in 'site evaluation' and 'site characterization' phases, when the stratigraphic well is drilled to acquire more data for detailed characterization of the the storage formation and regulatory testing of the well,
During well testing, the injectivity of formation will be estimated using step-rate test and Pressure Fall-off test (PFO), along with testing the seal integrity and the number of CO2 injectors needed for the project volume.
The calculator below estimates a one deterministic value of storage capacity (MT).
The best way is to use probabilistic approach using Monte Carlo Simulation; where, each input is entered as a pdf distribution to give a range of capacities (Low/Mid/High) to manage the subsurface uncertainty in parameters, rather than one deterministic value.
The calculator can quickly screen many sites to compile 'ATLAS of 'Selected Areas'