Composite gels for water shutoff in fractured reservoirs
A composition includes a colloidal solution which includes a solvent, a plurality of nanoparticles dispersed in the solvent, an activator dissolved in the colloidal solution, and a plurality of gel particles suspended in the colloidal solution. A method for water shutoff includes injecting a composition into a fracture near a water zone in a formation, wherein the composition includes a colloidal solution which includes a solvent, a plurality of nanoparticles dispersed in the solvent, an activator dissolved in the solvent, and a plurality of gel particles suspended in the colloidal solution.
1. A composition comprising:
a colloidal solution comprising a solvent, a plurality of silica nanoparticles dispersed in the solvent;
an activator dissolved in the colloidal solution, where the activator is selected from the group consisting of sodium silicate, sodium chloride, and potassium chloride; and
a plurality of gel particles suspended in the colloidal solution,
wherein the activator activates gelation of the colloidal solution under formation conditions, forming a composite gel comprising the plurality of gel particles, and
wherein the composite gel exhibits an elasticity ranging from 20,000 to 30,000 Pa.
2. The composition of claim 1 , wherein the plurality of gel particles are water-swellable.
3. The composition of claim 1 , wherein the plurality of gel particles comprise a polymer.
4. The composition of claim 3 , wherein the polymer is water-swellable.
5. The composition of claim 3 , wherein the polymer is selected from the group consisting of N—N methylene bisacrylamide and polyacrylamide.
6. The composition of claim 1 wherein the plurality of gel particles are sized from 500 micrometers to 3000 micrometers.
7. The composition of claim 1 , wherein the silica nanoparticles are surface modified with a silanol.
8. The composition of claim 1 , wherein the plurality of silica nanoparticles are sized from 10 nanometers to 14 nanometers.
9. The composition of claim 1 , wherein the composite gel exhibits a weight loss of less than 25% at 900° C.
10. A method for water shutoff in a formation comprising:
injecting a composition into a fracture near a water zone in a formation wherein the composition comprises:
a colloidal solution comprising a solvent, a plurality of silica nanoparticles dispersed in the solvent;
an activator dissolved in the solvent, where the activator is selected from the group consisting of sodium silicate, sodium chloride, and potassium chloride; and
a plurality of gel particles suspended in the colloidal solution; and
allowing the colloidal solution to gel, forming a composite gel comprising the plurality of gel particles,
wherein the composite gel exhibits an elasticity ranging from 20,000 to 30,000 Pa.
11. The method of claim 10 , wherein allowing the colloidal solution to gel occurs in situ in the formation.
12. The method of claim 10 , further comprising flushing the fracture with the colloidal solution.
13. The method of claim 12 , wherein flushing the fracture with the colloidal solution occurs prior to injecting the composition into the fracture.