Plugging and sealing subterranean formations
A subterranean formation sealant includes a mixture of an aqueous colloidal dispersion including silica nanoparticles and a C6-C12 fatty acid. Heating the sealant above 70° C. initiates gelation of the sealant. Sealing an opening in a water or gas producing zone in a subterranean formation includes providing a sealant including a mixture of a colloidal dispersion including silica nanoparticles and a C6-C12 fatty acid to the water or gas producing zone, initiating gelation of the sealant in situ, and solidifying the sealant in the water or gas producing zone to yield a set gel, thereby sealing the opening in the water or gas producing zone.
1. A subterranean formation sealant comprising a mixture of:
an aqueous colloidal dispersion comprising silica nanoparticles; and
a C6-C12 fatty acid,
wherein heating the sealant above 70° C. initiates gelation of the sealant.
2. The sealant of claim 1 , wherein a viscosity of the sealant at 20° C. is less than 5 cP.
3. The sealant of claim 1 , wherein the colloidal dispersion comprises at least one of a salt and a water-miscible organic solvent.
4. The sealant of claim 1 , wherein a size of the silica nanoparticles is in a range of 1 nm to 500 nm.
5. The sealant of claim 1 , wherein a concentration of the silica nanoparticles in the colloidal dispersion is in a range of 10 wt % to 50 wt %.
6. The sealant of claim 1 , wherein the C6-C12 fatty acid consists essentially of C6-C8 fatty acid.
7. The sealant of claim 1 , wherein the C6-C8 fatty acid comprises one or more of hexanoic acid, heptanoic acid, and octanoic acid.
8. The sealant of claim 1 , wherein a pH of the aqueous colloidal dispersion is in a range of 8 to 11.
9. The sealant of claim 1 , wherein a ratio of the C6-C12 fatty acid to the colloidal dispersion is in a range of 0.25 vol % to 5 vol %.
10. The sealant of claim 1 , wherein a pH of the sealant is in a range of 1 to 6.