Statoil CO2 storage experience: 20 years and 20 million tonnes Andrew Cavanagh, Anne-Kari Furre, Anders Kiær, Aina Dahlø Janbu, Bamshad Nazarian, Britta Paasch, Philip Ringrose | Statoil RDI CO2GeoNet 10th Anniversary Open Forum, 2015 Classification: Open 2015-05-12 Statoil storage projects 2008 2 Classification: Open 2015-05-12 1996 2004 The pioneering CCS project, Sleipner ! Main learning: CO2 storage is feasible The World’s first commercial-scale offshore storage project • Driver: Norwegian carbon tax • Storage unit: 800-1000 m depth, 200 m thick, high permeability • More than 15 Mt CO2 have been injected ! Challenges: − Role of internal shale layers on plume movement − Predicting CO2 flow properties ! Take-aways: − CO2 plume can be monitored by seismic and gravimetric methods − Down-hole monitoring would improve models 3 Classification: Open 2015-05-12 The pioneering CCS project, Sleipner ! Main learning: CO2 storage is feasible CO2 Condensate Injection point Injector (T. Torp, 2000) 4 Classification: Open 2015-05-12 Producers (A. Kiær, 2014) Sleipner monitoring Injected CO2 (Mt) ! Cost-effective geophysical portfolio design 14 Seismic surveying 12 Gravity surveying 10 Seafloor mapping 8 CSEM survey 6 4 2 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 Year 5 Classification: Open 2015-05-12 Sleipner model ! Understanding CO2 plume dynamics 6 Darcy flow method Percolating flow method (Singh et al., 2010) (Cavanagh, 2013; Cavanagh & Haszeldine, 2014) Classification: Open 2015-05-12 Sleipner model ! Plume calibration based on seismic • Darcy flow approach: − Viscous forces, reservoir simulation − Vertical equilibrium assumption (VE) − Poor match, strong pressure artifact • Percolating flow approach: − Capillary forces, basin modeling − Gravity assumption for migration (MGN) − Equally poor match, but is buoyancy closer? • We then allow the pressure to dissipate in the VE reservoir simulation, and the plume redistributes to its buoyant equilibrium position. A much better match to the footprint of the seismic observation is achieved. 7 Classification: Draft 2015-05-12 Sleipner model 460 ! 2-phase black oil reservoir simulation • Calibrating for 2008 seismic footprint based on pressure equilibrium 10 100 90 80 70 60 50 40 30 20 • Simulation time in years: 15 710 • Pressure field at the end of injection: ~ 460 to 710 kPa (65-100 psi) overpressure ~ 250 kPa (36 psi) drop over 3 km X 8 Classification: Draft 2015-05-12 Sleipner model ! Flow modelling favours near-equilibrium interpretation ! ## ! Dynamic#equilibrium## ! ! ! ! 1999#################2001#####2002#################2004#################2006#################2008# ! The simulation results clearly indicate that the plume beneath the caprock is gravity-dominated, and close to equilibrium at every observation point (Cavanagh, Energy Procedia, 2013) Reservoir simulations for CO2 storage may be susceptible to significant pressure artefacts that distort the model outcome. 9 Classification: Draft 2015-05-12 Testing the boundaries at In Salah ! Main learning: the role of geomechanics and monitoring Storage limits in a challenging environment • Driver: Joint Venture for technology development with BP and Sonatrach • Storage unit: 1880 m depth, 20 m thick, low permeability • 3.8 Mt CO2 injected from 2004 to 2011 ! Challenges: − Injectivity: low permeability formation limited injectivity and capacity − Geo-mechanics: integrating monitoring techniques and modelling ! Take-aways: − Developed pioneering onshore monitoring portfolio − Inclusive research approach resulted in many peer-reviewed papers 10 Classification: Open 2015-05-12 Testing the boundaries at In Salah ! Main learning: the role of geomechanics and monitoring Map of surface uplift May 2009 20mm uplift Injection unit Modelled rock strain (section) (Gemmer et al., 2012) 11 Classification: Open 2015-05-12 In Salah geomechanics Sketch of geological and fluid effects around injection well KB-502 (Ringrose et al. 2013) Lower caprock (Secondary Storage) Elevated pressure in reservoir volume 1km Depth Upper caprock (Main Seal) Carboniferous Rock mechanical strain propagating to surface Cretaceous ! Simple linear elastics not sufficient to explain observations ! Hydro-fractures and fracture flow observed Primary Storage Unit CO2 plume ~ 1 km 2km 12 Classification: Open 2015-05-12 In Salah geomechanics ! All hydro-fracture hypotheses reviewed by White et al. 2014 (PNAS) 4D seismic: Time-delay feature (reprocessed seismic) Modelling:pressure: Well-head Example analytical Monitoring reservoirmodel response KB 502 Interpretation: Most likely case • Fracture zone has propagated 200-300 m into the lower caprock • No loss of storage integrity 13 Classification: Open 2015-05-12 Applying the knowledge to Snøhvit ! Main learning: integrating geophysics and injectivity The world’s first offshore CO2 transport pipeline • Driver: Regulator license-to-operate (& carbon tax) • Distance: field-to-onshore facility is 150 km • Storage unit: 2600 m depth • Over 3 Mt CO2 has been injected since 2008 ! Challenges: − Reservoir heterogeneity − Near-well flow limits ! Take-aways: − Need for robust design of injection system in heterogeneous reservoirs − A good ‘Plan B’ is invaluable when reservoir uncertainties are large 14 Classification: Open 2015-05-12 Applying the knowledge to Snøhvit ! Main learning: integrating geophysics and injectivity CO2 Gas LNG plant (Melkøya) Injection point (Osdal et al., 2014) 15 Classification: Open 2015-05-12 Applying the knowledge to Snøhvit ! Main learning: integrating geophysics and injectivity Tubåen reservoir quality Detailed mapping based on 3D seismic CO2 Gas 16 Classification: Open 2015-05-12 LNG plant (Melkøya) Applying the knowledge to Snøhvit ! Response to pressure build-up in the Tubåen • CO2 injection into the Tubåen CO2 Formation injection until April 2011 (1 Mt) • Injection then diverted into the Stø Fmn following well intervention (1.9 Mt) Main field segment with gas producers N CO2 Injector GLC Stø Nordmela X Tubåen (Ji-Quan Shi et al., 2011) 17 Classification: Open 2015-05-12 S Lessons learned from the last 20 years 1. Can injected CO2 be monitored cost-effectively? • Yes" No " Maybe " 2. Do we have enough storage capacity? • Yes" No " Maybe " 3. Are we technically ready for very large projects? • Yes" No " Maybe " 4. Is CO2 storage safe? • Yes" No " Maybe " 18 Classification: Open 2015-05-12 Thanks to… Anne-Kari Furre Anders Kiær Aina Dahlø Janbu Bamshad Nazarian Britta Paasch Philip Ringrose Statoil CO2 storage experience: 20 years and 20 million tonnes Dr A J Cavanagh Principal Researcher RDI, CO2 Storage and EOR [email protected] 19 Classification: Open 2015-05-12
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