SACCCS Test Injection Workshop

Transcription

1 SACCCS Test Injection Workshop The Atlas on Geological Storage of CO2 in South Africa Project Team J Viljoen, F Stapelberg and M Cloete 24/10/2011, Gallagher Estates, Midrand CO 2 geological storage atlas was financially supported by both industry and government PetroSA, Sasol, Eskom, Anglocoal, Saneri, Council for Geoscience, PASA

2 Presentation layout Context Project Aims and Deliverables Data Availability Criteria for ranking sedimentary basins & storage potential Standards and formulae for estimating CO 2 storage capacities New Research Developments since CO 2 Atlas

3 Background To mitigate global warming there needs to be a reduction in GHG emissions. This can only be done by employing a portfolio of advanced energy technologies: Energy efficiency improvements Renewable energy sources Advanced bioenergy & biotechnologies Hydrogen & fuel cell technologies Nuclear power Carbon Capture and Storage (CCS) With CCS (a zero emission technology) fossil fuel resources can be rendered clean. However, there is little point in undertaking CCS in a country without a CO 2 geological storage capacity. The places with storage potential thus had to be identified in South Africa!

4 Project Aims and Deliverables The aim of the Atlas Project was to: Identify all on- and offshore sedimentary basins in South Africa with CO 2 storage potential. Evaluate all types of CO 2 storage, i.e. deep saline formations, oil and gas reservoirs and unmineable coal seams. Compile a literature-based, technical report containing observations covering the CO 2 storage potential of South Africa for a scientific readership. Compile a glossy-style storage atlas for a broad public readership, and Make recommendations on whether to continue with CO 2 storage assessments, in which basins and provide ideas for further R&D.

5 Standards and Quality Control All definitions and formulae of the SA CO 2 Storage Atlas are aligned with CSLF recommendations. The Technical Report was subjected to international peer review

6 Data availability - Tectonic stability of sedimenary basins Map of earthquake magnitudes inferred from maximum modified Mercalli-scale intensities (CGS) Map of seismic risk in South Africa (CGS)

7 Data availability Soekor oil & gas exploration data Porosity and permeability trends for sandstones, main Karoo Basin (after Rowsell and De Swart, 1976) Parameter Positive Negative Porosity > 20% < 10% Permeability > 300 md < 10 md

8 Data availability: dolerite/sediment ratio map for the Karoo Basin (redrawn from Winter and Venter, 1970).

9 Sketch showing a connected (dolerite) sill complex and associated extrusive features, hydrothermal vent complexes and volcanoes (after Planke, 2005).

10 Data availability Soekor oil & gas exploration data Occurrence of coal seams at depths between m

11 Data availability - offshore seismic data, exploration wells and reports (Petroleum Agency SA, 2007).

12 Criteria for assessing sedimentary basins & storage potential (modified after Bachu 2003, Gibson-Poole et al., 2006) Item Criterion 1 Tectonic setting Classes Very Unstable eg Intermediate unstable eg synrift, eg foreland setting subduction intramontane arc margin 2 Basin size Very small <1,000 km 2 Small, 1,000 5,000 km 2 Medium 5,000-1,000 3 Basin depth Very shallow (< 300 m) 4 Reservoir-seal pairs Shallow ( m) Mostly stable passive Stable, eg cratonic Large 5000 Very large 25,000 km 2 >50,000 km 2 Deep (>3,500 m) Intermediate m Poor Intermediate Excellent 5 Fault intensity Extensive Moderate Limited

13 Criteria and classes for assessing the CO 2 storage suitability of sedimentary basins (modified after Bachu 2003, Gibson-Poole et al., 2006) Item Criterion 6 Dolerite dykes/sheets 7 Geothermal gradient 8 Hydrocarbon potential Classes Extensive Moderate None Warm basin (>40ºC) Moderate basin (>40ºC) Cold basin (>40ºC) None Small Medium Large Giant 9 Maturity* Unexplored Exploration Developing Mature Over mature 10 Coal None Very shallow (<300 m) Very Deep (>1,500m) Deep (800 1,500 m) Shallow ( m) * = criteria not entirely geological

14 Criteria and classes for assessing the CO 2 storage suitability of sedimentary basins (modified after Bachu 2003, Gibson-Poole et al., 2006) Item Criterion Classes Coal rank Anthracite Lignite Subbituminous 12 On/offshore* Deep offshore 13 Economic* activities Large scale mining Active mining Shallow offshore Conirmed (no mining) Potential Bituminous Onshore 14 Infrastructure* None Minor Moderate Extensive None 15 Distance from CO 2 sources* >1,000 km 500 1,000km km >300 km * = criteria not entirely geological

15 Methodology for storage capacity calculations Deep saline aquifers: Coalbeds Oil & Gas reservoirs M CO2 = A t h g φ tot ρ E M CO2 = A t h g Cρ E M CO2 = A t h g φ c (1-S w ) ρ E M CO2 A t h g φ tot Mass estimate for saline formation CO2 storage capacity Geographical area of basin being assessed Gross thickness of saline formations being assessed Average porosity of saline formation ρ Density of CO2 evaluated at formation T and P of formation E CO2 storage efficiency factor reflecting fraction of total pore volume filled with CO2 C Concentration of CO2 absorbed onto coal at given pressure Average water saturation within a volume of reservoir S w (DOE 2007, 2008a; CSLF 2007; CO2CRC 2008; Kaldi and Gibson-Poole 2008)

16 Storage capacity calculations Northern Karoo Basin Algoa Basin No. of Samples 130 No. of Samples 2 Ave Porosity 7.1 % Ave Porosity 18.8 Ave Depth of aquifer 1150 m Ave Depth of aquifer 1550 m Geothermal gradient (ᵒC/100m) CO 2 density (kg/m 3 ) (Bachu, 2003) 1.93 & 3.69 Geothermal gradient (ᵒC/100m) 650 & 500 CO 2 density (kg/m 3 ) (Bachu, 2003) 2.81 & & 475

17 CO2 geological storage potential of South Africa

18 Post-CO 2 Atlas work in South Africa (SACCCS/SANEDI) Atlas and Technical Report on geological storage of carbon dioxide in South Africa Recommend on whether to continue with CO 2 storage capacity assessments in S.A. An effective CO 2 capacity assessment of the Zululand Basin Funded by UK High Commission An effective CO 2 capacity assessment of the Algoa Basin (WP2 SAfECCS, EuropeAid) Several research bursaries on aspects of mineral carbonation and geological storage Scoping of test injection in South Africa CO2 Capturereadiness of South African industries

19 2 nd South African CCS Conference Thank you

20 2 nd South African CCS Conference Atlas on geological storage of CO2 in South Africa Project Team M Cloete, J Viljoen and F Stapelberg 25/10/2011, Gallagher Estates, Midrand CO 2 geological storage atlas was financially supported by PetroSA, Sasol, Eskom, Anglocoal, Saneri, Council for Geoscience, PASA

21 Sedimentary basins of South Africa screened for geological storage of CO2