1. Stefan Iglauer, Saleh K Al-Mansoori, Christopher H Pentland, Branko Bijeljic, Martin J Blunt 2 Phase Measurement of Non-Wetting Phase Trapping

2. 2 Outline 1.Background 2.Motivation 3.Experimental Overview 4.Results 5.Future work Why am I up here talking about (oil-brine and air-brine) sand packs? Because of…. the importance of capillary trapping to CO 2 storage Application to residual hydrocarbon saturations in producing fields and carbon storage.

3. 3 Background Carbon Storage - How can you be sure that the CO 2 stays underground? Dissolution CO 2 dissolves in water (p, T, salinity of brine) – 1,000-year timescales denser CO 2 -rich brine sinks Chemical reaction acid formed carbonate precipitation – 10 3 – 10 9 years Hydrodynamic Trapping Trapping by impermeable cap rocks Capillary Trapping rapid (decades): CO 2 as pore-scale bubbles surrounded by water. Process can be designed: SPE 115663 Qi et al. host rock

4. 4 Motivation How effective is capillary trapping? What magnitude will the residual saturations be? Existing literature data for oil/water & gas/water systems in both consolidated and unconsolidated systems.

5. 5 Motivation Wide scatter in literature S (nw)r versus S (nw)i data. Which is the most effective storage medium consolidated or unconsolidated formations? consolidated unconsolidated Trapping Capacity = ϕ S (nw)r

6. 6 Experimental Set Up 1m sand packed column (PMMA) Wetting phase – Brine (5wt% NaCl + 1wt% KCl) Non-wetting phase – n-Octane or air Sand – LV60 (poro = 37%; perm = 32D) Oil injection rate = 0.5ml/min (N cap = 10 -6 ) Air injection rate = gravity drainage Brine injection rate = 5ml/min (N cap = 2 x 10 -5 )

7. 7 Oil-brine experiments - Experimental Procedure Pack column with sand Packing ratio used to give reproducible porosity Fully saturate column with brine Known volume of oil injected into the column from the top Different experiments performed – 30ml, 50ml, 80ml of n-Octane Column is inverted and oil rises from the bottom due to density difference Experiment ended when the first drop of oil reached the top of the column Column positioned horizontally & either sliced for S oi or waterflooded to reach S or. Column sliced and sampled. Analysis of saturations in each section done with gas chromatography, GC. Thermal Conductivity Detector (TCD) allows water to be analysed Repeat (reproducibility)

8. 8 Oil-brine experiments - Experimental Results Initial oil saturation curves (S oi ) Residual oil saturation curves (S or ) – post waterflooding GHGT-9

9. 9 Oil-brine experiments - Experimental Results GHGT-9

10. 10 Experimental Results – Comparison with Trapping Equations

11. 11 Air-brine experiments - Experimental Procedure Pack column with sand Packing ratio used to give reproducible porosity Fully saturate column with brine Air enters column by opening top and bottom to atmosphere (gravity drainage) Draining time was 3 hours and 30 minutes Column was either sliced for S gi or waterflooded (from the bottom) to reach S gr. Column sliced and sampled. Saturation measurement of each section via mass balance. Repeat (reproducibility)

12. 12 Air-brine experiments - Experimental Results Residual gas saturation curves (S gr ) – post waterflooding Initial gas saturation curves (S gi )

13. 13 Air-brine experiments - Experimental Results

14. 14 Experimental Results – Trapping curves GHGT-9

15. 15 Experimental Results – Comparison with Literature Data GHGT-9

16. 16 Future Work Consolidated media Sandstone (started) Carbonates Reservoir conditions Supercritical carbon dioxide Study link between trapping and system variables: Pore size distribution IFT / contact angle

17. 17 Acknowledgements Shell-Imperial Grand Challenge on Clean Fossil Fuels ADNOC Thank you!

18. 18 Trapping Equations Equation 1Land, 1968 Equation 3Jerauld, 1997 Equation 4Ma & Youngren, 1994 Equation 5Kleppe et al., 1997 Equation 6Aissaoui, 1983 Equation 7Spiteri et al., 2005 where