Vertically-Averaged CO2 Migration with Residual-Trapping And

Practical Models for Large-Scale CO2 Injection, Migration and Trapping Sarah Gasda Uni Research CIPR, Bergen, Norway [email protected] +47 555 83394 EU Emissions Objectives • 2030 Framework for climate and energy policies calls for emissions reduction under 1990 levels of 40% by 2030 and 80% by 2050. • By 2050, 80 Gt CO2 should be kept out of atmosphere by a combination of renewables, conservation and CCS. • IEA 2013 road map assumes that Europe should be able to capture and store 12.2 Gt of CO2 by 2050, at a rate of ~400 Mt of CO2/yr. EU Commission, 2014 North Sea Storage Evaluation • North Sea is the likely target for Europe’s emissions • 45 Gt capacity estimated in Norwegian sector. • Additional 5.6 Gt capacity in the Norwegian and Barents Sea. • Most capacity is in the Utsira/Skade and Bryne/Sandnes formations. Reaching Storage Potential • Reaching target capacity is largely determined by trapping mechanisms and mechanical integrity. • How much can we realistically inject? • How efficient is trapping? • How sensitive are estimates to parameter uncertainty? IPCC 2005 • What data do we need and Focus is on process which models are better suited? understanding, • What factors can help increase modeling, and robust and reliable simulation storage potential? 20 Mt injected over 20 yrs into a homogeneoust=25000 dipping aquifert=35000 t=100000 t=200000 0 0 0 0 0 yr mobile 8000 8000 mobile 8000 8000 0 16000 0 16000 0 16000 0 16000 t=25000 t=35000 t=99500 t=200000 600 yr 0 0 0 0 2500 yr 8000 8000 8000 8000 0 16000 0 16000 0 16000 0 16000 6250 yr 12,500 yr Residual 22,000 yr and Residual dissolved mobile mobile Weak Residually Strong convective- trapped convective- dissolution Residually Solubility dissolution trapped trapped Gasda et al., WRR, 2011. Choice of Modeling Tools • Standard reservoir simulators, e.g. Schlumberger- Eclipse, CMG-GEM, LBNL-TOUGH, … – readily available – “full-physics”, e.g. compositional, thermal, mechanics ... – accurate when resolved sufficiently – long run times for complex systems – difficult to implement new physics/chemistry/… – often incompatible for large sensitivity studies Simplified Model Philosophy • To solve the full problem is complex and expensive. • Need efficient, accurate models to allow for fast estimation with only the essential physics. • Look for acceptable simplifications based on inherent physical characteristics. • Free up computational resources to handle the mechanics or other small-scale processes that need to be resolved. Vertical Equilibrium Models ζT B ζ M Brine b CO2 ζB • Long thin tongue of CO2 extending away from injection. • Gravity segregation and negligible vertical flow at given timescale. Reduces to primarily horizontal flow. • Integrate vertically to reduce dimensionality. • Solve semi-analytically or numerically. Vertical Equilibrium Models • Well suited for large-scale, gravity- dominated systems • Coupled with more complex “3D” processes, accurate EOS models, analytical solutions, subscale phenomena, … • Fast, minutes instead of hours, and accurate, compares well with reservoir models • Run many realizations to explore sensitivity/uncertainty in parameter space Gasda et al. ECMOR XIII, 2012 Examples of VE models for CO2 -1200 ] -1300 m [ h t p e d -1400 -1500 10 15 20 25 30 35 40 km -1200 ] -1300 m [ h t du Plessis et al.,JCSMD 2014 p e d -1400 -1500 10 15 20 25 30 35 40 km Gasda et al. AWR, 2013 Many complex problems can still be tackled with simple models! Gasda et al, WRR, 2011 Elenius and Gasda, AWR, 2013 Utsira Topography and Porosity BGS dataset: Kirby et al (2001) Depth mapping and characterisation of the Utsira Sand Saline Aquifer, Central and Northern North Sea Porosity (%) Top (m) Thickness (m) Large-scale Capacity of the Utsira Sand Saturation Overpressure bar 1.5 Gt Injected over 50 years Estimate Mechanical Impact Height change (m) • What is the maximum sustainable overpressure? • What measures, such as minimum stress, caprock uplift and curvature, can be used to define the upper limit on CO2 injection rates? Research goals • Develop and apply large-scale VE models to assess storage site capacity and trapping efficiency • Investigate maximum injection rates through integrated mechanical/flow models. • Develop models in VE framework to assess leakage risk through upscaled faults, fractures and wellbores. Remarks • Industrial-scale CO2 storage will require capacity and pressure management beyond what we have experienced to date. • Maximizing storage potential, or trapping efficiency, depends on effectively managing the physical and chemical processes within heterogeneous systems. • Storage evaluation depends on reliable modeling tools and high-quality data, to the extent possible. • Vertically-integrated modeling framework can help overcome limitations of model resolution for large-scale simulation. • Small-scale physical processes can be upscaled, reducing computational cost and geologic model complexity. Acknowledgements • Students and postdoc – Elsa du Plessis (hysteresis) – Odd Andersen (compressibility) – Bawfeh Kometa (thermal modeling) • Colleagues and Collaborators – Helge Dahle, Jan Nordbotten (UiB) – Halvor Nilsen (SINTEF) – Michael Celia (Princeton) – Ivar Aavatsmark (Uni CIPR) .

Load more