Capacity of large-scale CO2 storage in North Sea sloping aquifers from numerical simulation (LCSANS)
Climit-finansiering6.5 MNOK from the Research Council. The rest is own financing and industrial financing
PartnereUNI CIPR, Foundation CMG Total E&P Norge AS RWE Dea Norge AS
Prosjektperiode2013 – 2016
The key aspects of successful large-scale CO2 storage are evaluating the capacity of suitable storage sites and understanding the risk of injecting CO2 into large open systems. In the North Sea, many suitable saline aquifers have been identified in the ea stern provinces, ranging from the relatively shallow Utsira and Skade aquifer to the deeper Johansen and Cook Formations, each with enormous volumes of potential storage capacity for CO2.
Estimating the practical or realistic storage capacity requires a fundamental understanding of how CO2 migrates and is eventually trapped in these aquifers over long timescales. By investigating the uncertainty in storage capacity and identifying important factors that affect this uncertainty, we can determine the optimal injection strategies to attain the maximum capacity possible for a given storage site.
Primary objective: Development of a best practice manual for assessment of CO2 storage in sloping aquifers by numerical simulation. Secondary objectives:
1. Compare simulation tools on representative data sets for CO2 storage on the Norwegian Shelf.
2. Quantify the uncertainty associated with different equations of state for relevant storage conditions.
3. Quantify the effect of caprock topography for relevant CO2 storage data sets.
4. Make a broad sensitivity study on the effects of boundary conditions and parameterization for CO2 storages.
5. Include vertical cross-flow and pressure-induced geomechanical deformation in the vertical-equilibrium model and implement these effects in the in-house simulator.
1. Implementation of robust and reliable simulation code for large-scale and longtime CO2 storage in sloping aquifers.
2. Understanding of impact of uncertainties on storage capacities.
3. Application of the simulation tools on relevant storage sites on the Norwegian Shelf. Application potential: Evaluation of capacity of relevant CO2 storage sites and open software for such evaluations.
- Tools for efficient simulation, sensitivity studies and analysis of large data amounts have been developed. An initial vertical equilibrium (VE) model for the Skade benchmark set is written, and work and its relation to topography and boundary conditions has started. Tools to effectively study parameters and risk-assessment have been developed. These tools have so far only been tested on VE models. Tools for effective data mining / analysis of large amounts of data have likewise been developed. These tools will be important in the subsequent comparison and sensitivity studies.
- A simulation model for the Skade formation has been generated in Eclipse300. A simulation model in TOUGH2 has been set up. In order to make the model comparable to the Eclipse model, the model was built based on a two conversion scripts. The first transferred the Eclipse grid model to a TOUGH2 grid model, and the second took a general description of input data and generated two input data files, one for TOUGH2 and one for Eclipse300. The second script was written in perl and also extracts output data from the two simulations such that they can be easily compared and plotted in Matlab or other plotting tools. It can also automate the processes of running simulations on an external server. Further, since the CMG GEM simulator has an input data file similar to that of Eclipse, it is believed that the perl script should be easily extensible to the CMG GEM simulator.
- Aquifers which are candidates for CO2 storage, are often of no commercial petroleum interest, and thus there are few or no core samples from the area. However, some insight into how the presence of both formation water and CO2 simultaneously affect the flow is needed to obtain representative studies of the storage process. A review of the literature has been made to map the reported correlation between the variables, and thus build an average image that can be assumed to be typical.
- A generalized cubic equation of state has been developed. Optimal adaption to CO2 for predefined pressure-temperature ranges has been developed. This generalized cubic equation of state is now under implementation in the CMG simulator GEM.
- An explicit function for solubility of water in dense-phase carbon dioxide has been derived. Using this function, the undersaturation of injected CO2 at the bottomhole state can be determined and the dehydration nearwell zone can be estimated.