Search

Abstract: The offshore gas fields in The Netherlands provide a storage capacity of about 1 Gt, which will become available over the next few decades. Existing production facilities may be re-used for injection. Uncertainties in storage capacity, injection rates and time of availability require an analysis of the feasibility of storing CO2 at the rates currently projected for the period 2015–2050. This paper investigates the availability of storage capacity and the feasibility of injecting CO2 at the rate that current capture scenarios foresee. The cost of storage in depleted gas fields is estimated, assuming either re-use of existing installations or the construction of new platforms and wells. Unit cost of storage, non-discounted, in the range of 10 € /t CO2 is feasible for larger fields; costs for small fields are estimated to range up to 40 € /t CO2. Constructing new, dedicated facilities is not always the more expensive option, due to sometimes long hibernation times and higher operational cost of existing facilities. Two capture scenarios are used for the Rotterdam and Amsterdam areas, with captured volumes increasing to 25 Mt/yr or 40 Mt/yr. In both cases, injection rate limitations become apparent when 70–75% of the storage capacity is used, which is around 2055 and 2045, respectively. To ensure continuity of storage, alternatives for storage in offshore gas fields need to be in place by then. [Copyright &y& Elsevier]

Abstract: Over the past few years several geochemical evaluations of CO2 storage in Dutch potential reservoirs are carried out, including predictions of the short- and long-term impact of CO2 on the reservoir using geochemical modelling. The initial mineralogy of the reservoir is frequently obtained from core analysis and is then used to compute the formation water composition. In this paper geochemical modelling with TOUGHREACT is used to predict and compare the short- and long-term geochemical impact of CO2 injection into three reservoirs. The mineralogical composition of these reservoirs is an assemblage based on commonly observed minerals from the Buntsandstein and Rotliegend formations. These formations contain potential onshore and offshore CO2 storage locations in the Netherlands. The results predict drying out and salt precipitation in the near-well area, due to water evaporation by the injected dry CO2. Several mineral transformations are predicted, dominated by the transformation of albite into dawsonite, thereby fixing CO2. Due to the relatively low density of dawsonite, the porosity significantly decreases, which can lead to a pore pressure increase. Disabling of dawsonite precipitation in the simulations, thereby taking into account the ongoing debate on dawsonite stability, only shows a small increase of the porosity. Future (experimental) work should be focused on dawsonite occurrence for accurate predictions of the long-term reservoir integrity. [Copyright &y& Elsevier]