Fabrication of micromodels for carbonate reservoirs
A carbonate microfluidic model with controllable nanoscale porosity and methods are described. The method for fabricating a carbonate nanofluidic micromodel with controllable nanoscale porosity for studying fluid behaviors in an underground oil-reservoir environment includes: disposing a plurality of polymer spheres into a transparent flow cell; initiating crystallization of the plurality of polymer spheres to form a template with an opal structure; filling the transparent flow cell with a calcium-based solution and a carbonate-based solution to form nanocrystals in voids of the opal structure; and removing the template formed by crystallization of the plurality of polymer spheres from the transparent flow cell leaving an inverse opal structure with a plurality of nanoscale pores and a carbonate surface. The model includes: a transparent flow cell including a first end defining an inlet and a second end defining an outlet; and an inverse opal structure of carbonate inside the transparent flow cell.
1. A method for fabricating a carbonate nanofluidic structure with controllable nanosized porosity for studying fluid behaviors in an underground oil-reservoir environment, the method comprising:
synthesizing a plurality of polymer spheres;
purifying the plurality of polymer spheres in deionized water and redispersing the plurality of polymer spheres in a 1:1 ratio of a water-ethanol mixture;
disposing the plurality of polymer spheres into a transparent flow cell;
initiating crystallization of the plurality of polymer spheres to form a template with an opal structure;
filling the transparent flow cell with a calcium-based solution and a carbonate-based solution to form nanocrystals in voids of the opal structure;
growing an inverse opal structure of calcium carbonate or calcium-magnesium carbonate in opal structured template; and
removing the template formed by crystallization of the plurality of polymer spheres from the transparent flow cell leaving an inverse opal structure with a plurality of nanosized pores and a carbonate surface.
2. The method of claim 1 , wherein the transparent flow cell has a light path between 0.05 and 1 millimeter (mm) and a volume between 16 and 300 microliters (μL).
3. The method of claim 1 , wherein the plurality of polymer spheres has a size between 50 nanometers (nm) and 1000.
4. The method of claim 1 , further comprising crystallizing the plurality of polymer spheres inside the transparent flow cell by drying them at 60 Celsius (° C.) for 30 minutes.
5. The method of claim 1 , wherein the calcium-based solution further comprises magnesium.
6. The method of claim 5 , wherein forming the calcium-based solution comprises dissolving a solid CaCl 2 .2H 2 O solution in deionized water as a precursor for the formation of a calcite.
7. The method of claim 5 , wherein forming the calcium-based solution comprising magnesium comprises dissolving CaCl 2 .2H 2 O and MgCl 2 .6H 2 O solutions at 1:1 molar ratio in deionized water as a precursor for the formation of a dolomite.
8. The method of claim 5 , wherein forming CaCO 3 or CaMg(CO 3 ) 2 crystals into the transparent flow cell includes injecting 1M CO 3 2− into the transparent flow cell to react with the calcium or magnesium-based ions.
9. The method of claim 8 , wherein forming 1M CO 3 2− includes dissolving a Na 2 CO 3 or (NH 4 ) 2 CO 3 solution in deionized water.
10. The method of claim 8 , further comprising filling the voids of the transparent flow cell with the CaCO 3 or CaMg(CO 3 ) 2 solution by injecting the calcium or magnesium-based solution and the CO 3 2− solution into the transparent flow cell and drying at 150° C. for 2 hours.
11. The method of claim 1 , further comprising immersing the transparent flow cell into a toluene solution overnight and dissolving the plurality of polymer spheres.
12. The method of claim 11 , further comprising injecting the toluene, a chloroform, or an acetone solution into the transparent flow cell to wash the dissolved plurality of polymer spheres.
13. The method of claim 11 , further comprising forming the inverse opal structure with a plurality of nanosized pores by sintering the transparent flow cell at 280° C. for 2 hours.
14. A method for fabricating a carbonate nanofluidic structure with controllable nanosized porosity for studying fluid behaviors in an underground oil-reservoir environment, the method comprising:
disposing a plurality of polymer spheres into a transparent flow cell;
initiating crystallization of the plurality of polymer spheres to form a template with an opal structure;
filling the transparent flow cell with a calcium-based solution and a carbonate-based solution to form nanocrystals in voids of the opal structure;
growing an inverse opal structure of calcium carbonate or calcium-magnesium carbonate in opal structured template;
immersing the transparent flow cell into a toluene solution overnight and dissolving the plurality of polymer spheres; and
removing the template formed by crystallization of the plurality of polymer spheres from the transparent flow cell leaving an inverse opal structure with a plurality of nanosized pores and a carbonate surface.
15. The method of claim 14 , further comprising injecting the toluene, a chloroform, or an acetone solution into the transparent flow cell to wash the dissolved plurality of polymer spheres.
16. The method of claim 14 , further comprising forming the inverse opal structure with a plurality of nanosized pores by sintering the transparent flow cell at 280° C. for 2 hours.
17. The method of claim 14 , wherein the transparent flow cell has a light path between 0.05 and 1 millimeter (mm) and a volume between 16 and 300 microliters (μL).
18. The method of claim 14 , further comprising synthesizing the plurality of polymer spheres.
19. The method of claim 18 , further comprising purifying the plurality of polymer spheres in deionized water and redispersing the plurality of polymer spheres in a 1:1 ratio of a water-ethanol mixture.