1. Observations of Microdrop Decan and Oil on Mica Surface by AFM and VSI. Ueda, A. 1, Kunieda, M. 1, Fukunaka, Y. 1, Liang, Y. 1, Matsuoka, T. 1 and Okatsu, K. 2 1 Kyoto University 2 The Technology and Research Center, Oil, Gas and Metals National Corporation (JOGMEC)

2. -Background “EOR ⇔ NANO”- High recovery =EOR (Enhanced Oil Recovery) ⇒ Viscosity, Fluidity, Substitution efficiency… micro-phenomena controls the wettability (contact angle, surface tension) in oil-mineral-fluid

3. quartzcarbonateclay rock Oil quartzcarbonateclay Sea water quartzcarbonate Sea water ＋ chemical brine Water-oil-rock (Enhanced oil recovery) Vapor/fluid solid liquid （ Young’s equation ） clay

4. Comparison of computational and experimental results

5. 5

6. The previous results presented in 2008 （北京）

7. Contact angle vs Salinity of brine Cruide oil Higashi-Niigata LocalityNiigata Density(g/cm 3 )0.784 API49.0 Velosity(30 ℃ ) 1.2

8. Observation of oil droplet on mica by AFM (Oil diameter ;400nm)

9. Observation of oil droplet by VSI (Vertical Scanning Interferometry) in distilled water at 25 ℃ and 1 atm 9

10. The results in 2009 (A preliminary report)

11. Macro analyses R h Decane H 2 O droplet θ/2 method R = 159 μm h = 20 μm Θ= 28.2 ° C 10 H 22 0.7g/cm 3

12. mica H2O droplet Decane H2O 5m Decane 500ml Naturally deposition for 1 hour Cleanup mica surface with water Make Mica cleavage Splash by air compressor Soak mica in Decane for 1 day Mica preparation Contact angle measurement Small emulsion (~10 micro m) Large emulsion (10 micro m~) Decane H2O Ultrasonic bath Magnetic stirrer Sample preparation for micro droplet H2O ~1ml Decane 100ml

13. Cantilever: k=0.01 Pressure: 2.5nN Scan rate: 0.5Hz 1μm×1μm Root mean square Roughness Roughness; 0.75nm ⇒ smooth surface in nanoscale Mica surface in decan (AFM)

14. 5μm×5μm Rms roughness; 0.32nm Cantilever: k=0.01 Pressure: 2.5nN Scan rate: 0.5Hz H2O droplet Water droplet in decan (AFM)

15. R=2.109 micro m H=92.25 nano m Contact angle 12.7 degree (θ/2 method) Contact angle of water droplet in decan 5μm×5μm R h θ/2 method

16. Contact angle of water droplet in decan on mica surface (f=2.5nN) Cantilever: k=0.01 Pressure: 2.5nN Scan rate: 0.5Hz

17. Effect of cantilever pressure on contact angle Is it a real contact angle? R~10 micro m h=456.6 nano m Contact angle= 10.7° F=2.5nN Cantilever: k=0. 1 Pressure: 25nN Scan rate: 0.5Hz F=25nN ×

18. Contact angle of water droplet in decan on mica surface C.Pressure(low) C.Pressure(high)

19. Error signal Topography Effects of scanning pressure Real surface Apparent surface cantilever F=25nN AA=15.4 micro m (Differential calculus)

20. Effects of scanning pressure cantilever Force curve near water droplet ApproachRetract Decan on mica surface In H2O droplet Approach Retract ＊

21. Correction of contact angle Error signal ⇒ contact angle correction Force curve ⇒ height correction

22. Contact angle vs. oil size (AFM) Modified Young’s equation Similar value to the observed one in macro scale

23. Vertical Scan Interferometry (VSI)

25. Reaction cell for high T and P (~200 ℃, ~20MPa)

26. Width ： 9.9μm Height ： 0.52μm Contact angle ＝ 12.0 ° Water droplet in decan (VSI)

27. 27 hydrophilic no hydrophilic 5nm α-Quartz Hexane CH 3 (CH 2 ) 4 CH 3 H2OH2O

28. Thank for your attention.