BGR Bundesanstalt für Geowissenschaften und Rohstoffe

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R & D Project CO2-STORE

Country / Region: Germany

Begin of project: February 1, 2003

End of project: July 31, 2006

Status of project: July 31, 2006

Figure 1: Schwarze Pumpe power plant. Figure 1: Schwarze Pumpe power plant. Source: Vattenfall

Among others, storage of carbon dioxide (CO2) in deep geological formations is considered to be one option to mitigate unfavourable climate changes. With the objective of long term advancement of living conditions, BGR contributes to several EU-founded projects which investigate the possibility of CO2-storage in the deep geological formations.

Besides depleted oil- and gas fields and unminable coal seams, saline aquifers are of great importance due to their area wide extension and their high storage potential.

The CO2STORE research and development project investigates the off-shore and on-land long term carbon dioxide storage in saline aquifers.

The project is jointly funded by the European Commission No.: NNE5-2001-00513 and a consortium of industry partners. Website: Research project CO2STORE.

Main objectives of the project are the transfer of knowledge gained in the SACS project to other potential storage sites off-shore and on-land, and the improvement and testing of geophysical monitoring methods of CO2 injected into the Utsira formation.

Case studies investigated in this project are located in Wales/St. Georges Channel, Mid-Norway, Denmark and in northeast Germany.

Participants in the German case Study “Schwarze Pumpe” are: NITG-TNO (The Netherlands), BRGM (France) and Vattenfall Utveckling AB (Sweden) (see list of links below). The research activities for this case study are coordinated by BGR.

In addition, a simulation study was performed by BGR and LBNL for CO2 storage to increase natural gas recovery in the Altmark natural gas field.


Objectives

Figure 2: Salt structures in northeast Germany.Figure 2: Salt structures in northeast Germany. Source: BGR

Within the German case study “Schwarze Pumpe” the main target is to discover, evaluate, and characterise potential storage sites (saline aquifers) in north-eastern Germany. The selected site should be capable to store more than 400 Megatons of CO2 according to the average CO2-emission of a modern, lignite fired power plant like the “Schwarze Pumpe” (Figure 1) within 40 years of operational life time. The “Schwarze Pumpe” plant operated by Vattenfall is located in the federal state of Brandenburg (Niederlausitz), about 100 km southeast of Berlin (Figure 2). The modern coal fired power plant Schwarze Pumpe located in the south-eastern part of Brandenburg (Niederlausitz) consists of two blocks, each having a capacity of 750 MW electricity and around 250 MW heat. In total, both blocks emit around 10 Megatons CO2 annually.

Interdisciplinary R&D tasks are:

  • the selection and characterisation of an aquifer storage site (BGR)

  • numerical modelling of geochemical reactions (BRGM)

  • generation of a 3D geological reservoir model (TNO and BGR) for the simulation of fluid migration in the reservoir induced by CO2 injection (TNO)

  • risk assessment (Vattenfall, TNO and BGR)


Site Selection and Characterisation

In an initial survey, several suitable storage sites (saline aquifers) have been identified from a large number of anticlinal structures within Mesozoic formations in the Northeast German Basin. With respect to several geological selection criteria (depth, thickness, porosity, permeability, expected storage volume, presence of structural closures and sealing cap rocks) a ranking of 26 investigated structures were conducted. Accordingly, the structure Schweinrich was selected as the best candidate for further investigations for this project (see Figure 2).

Figure 3: Cross section of the Schweinrich structure, an anticlinal closure positioned between two salt diapirs. The yellow arrows indicate the reservoir and storage position.Figure 3: Cross section of the Schweinrich structure, an anticlinal closure positioned between two salt diapirs. The yellow arrows indicate the reservoir and storage position. Source: BGR

The geological characterisation of the Schweinrich structure comprises the survey of

  • the structural framework

  • a detailed reservoir characterisation

  • extensive geochemical and mineralogical characterisations of reservoir and cap rocks.

  • the shallow subsurface (Tertiary and Pleistocene groundwater aquifers)


The selected storage site “Schweinrich” is a passive anticlinal structure (so called “turtle structure”) located between two salt diapirs. The reservoir (saline aquifer) within the lower Jurassic and the uppermost Triassic (Figure 3) consists of several layers of fine-grained, highly porous sandstones overlain by thick Jurassic clay formations.


Predictive geochemical modelling

Figure  4: Microprobe analysis of the Hettang reservoir proving the existence of CO2-reactive components like feldspars, carbonates and sulfides (reservoir rock).  Figure  4: Microprobe analysis of the Hettang reservoir proving the existence of CO2-reactive components like feldspars, carbonates and sulfides (reservoir rock).   Source: BGR

Besides well core analysis (lithology, stratigraphy), data from mineralogical and geochemical analysis provide most relevant input data for the modelling work. Reactive components in the reservoir sandstones are predominantly feldspars and Fe-bearing carbonates (Figure 4).

The geochemical modelling indicates the potential geochemical sensitivity of the reservoir and the cap rocks to CO2 injection into the reservoir and helps to predict

  • likely CO2-brine-rock interactions in the reservoir

  • the capacity of the reservoir rock to dissolve CO2 and to trap it in solid minerals

  • the geochemical impact of CO2 intruding the cap rock through reactivated faults

  • the risk of CO2 degassing and pressure build-up due to mixing of formation waters with different salinities



3D reservoir modelling and flow simulations

Figure 5: Simulated spread of CO2 in formation water, 10,000 years after the injection (volume fraction of CO2 in the brine). Note the flow of dense CO2-rich brine from the crest down the flanks of the structure.  Figure 5: Simulated spread of CO2 in formation water, 10,000 years after the injection (volume fraction of CO2 in the brine). Note the flow of dense CO2-rich brine from the crest down the flanks of the structure.   Source: NITG-TNO

The 3D geological model of the storage reservoir has been created. It is used to simulate the propagation of the injected CO2, within the aquifer, its dissolution in the formation water, and the movement of the saline formation water. Simulations of up to 10,000 years help to predict the long term fate of the injected CO2 (Figure 5). The model will also be used to compare different injection strategies and supports planning the number and location of injection wells.

Risk Assessment

The main objective of the risk assessment is to analyse and evaluate possible health, safety, and environmental risks (HSE). Therefore, features and events leading to processes that can cause harm to HSE have been identified and classified with regard to their probability and the consequences resulting in the case of failures or accidents.

Besides the analysis of the reservoir and cap rock integrity carried out in this project, a study to investigate the sensitivity of the shallow subsurface system including the uppermost geological formations has been initiated. It comprises:

  • geological survey of the shallow subsurface

  • simulation of spatial and temporal spread of CO2 in shallow potable groundwater aquifers (in the case of leakage)

  • geochemical evaluation of hazards of groundwater acidification and contamination

Links

Research project CO2STORE

Partner:

Promotion / document number:

European Commission No.: NNE5-2001-00513

Contact:

    
Dr. Franz May
Phone: +49 (0)511-643-3784

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