Method for making nano- and micro-particles for use as a proppant and fluid-loss-control additive
Nano- and micro-particles (NMP) can be formed from an oil/water emulsion. The emulsion is made by mixing a liquid solvent, at least one surfactant, a particle-forming compound, and at least curing agent. If desired, pH control agents and viscosity enhancers can be added to the liquid solvent. The particle-forming compound and the curing agents are mixed together and form the oil phase in the emulsion and after curing, the particles are formed. The nano- and micro-particles can be used as proppant to enhance the conductivity of nano- and microfractures and fluid-loss-control additive for hydraulic fracturing operations.
1. A liquid for making an oil/water emulsion to form a mixture of nano- and micro-particles, comprising:
at least one surfactant;
a micro-emulsion flowback aid;
seawater, the seawater comprising between about 29.6-36.8 wt % of the liquid;
a pH control agent, wherein increasing the weight percentages of the seawater and the pH control agent decreases a range of particle diameters for the nano- and micro-particles that are formed, the diameters of the nano- and micro-particles being under 100 μm for all of the nano- and micro-particles;
an epoxy resin; and
at least one curing agent.
2. The liquid of claim 1 , wherein the at least one surfactant is a polyoxyethyene (20) sorbitan monolurate surfactant and comprises between about 2.9-3.7 wt % of the liquid.
3. The liquid of claim 1 , wherein the micro-emulsion flowback aid comprises:
10-20% by weight proprietary ingredient 6615, 10-20% by weight ethoxylated isotridecanol, 1-10% proprietary ingredient 6715, 1-5% solvent naphtha, 0.1-1% by weight naphthalene,
less than 12% by weight “alcohols, C11-14-iso, C13 rich, ethoxylated”, less than 10% by weight polyoxyethylene monobutyl ether, less than 5% propylene glycol, or
less than or equal to 50% by weight proprietary ingredients, less than or equal to 15% by weight solvent naphtha, less than or equal to 10% Ethoxylated alcohol; and comprises between about 6.7-8.6 wt % of the liquid.
4. The liquid of claim 1 , wherein the pH control agent comprises between about 1.4-1.8 wt % of the liquid.
5. The liquid of claim 1 , wherein the epoxy resin comprises:
90-100% phenol, 4-(1-methylethylidne) Bis, polymer with (chloromethane) Oxecrane, 1-20% epoxide diluent, 0-10% modified epoxy novalac, 1-0.5% non-silicone additive,
an epoxy embedding medium, or
a 75-90% by weight modified derivatives of bisphenol a resins, 5-10% by weight modified derivative of cycloaliphatic resin, 1-3% by weight acrylated monomer, and 3-10% by weight glycidyl ether (c12-c14 alkyloxy); and
comprises between about 29.6-36.8 wt % of the liquid.
6. The liquid of claim 1 , wherein the curing agent comprises
5-15% by weight benzyl alcohol, 15-35% by weight isophoromediamine adduct, and 50-60% by weight aliphatic amine adduct, or
30-60% by weight 4,4 Methylenebis(cyclohexylamine), 30-50% by weight 3,3(Oxybis(2, 1 ethane-diloxy))bis 1-propanamine, or
75-90% by weight modified derivatives of bisphenol a resins, 5-10% by weight modified derivative of cycloaliphatic resin, 1-3% by weight acrylated monomer, and 3-10% by weight glycidyl ether (c12-c14 alkyloxy); and
comprises between about 12.3-30.0 wt % of the liquid.
7. The liquid of claim 1 , further comprising:
a viscosity enhancer comprising calcium carbonate nanoparticles, silicate nanoparticles, or water-soluble polymers comprising polyacrylamide or polyvinyl alcohol.
8. The liquid of claim 1 , wherein the pH of the liquid is above 12.
9. The liquid of claim 1 , wherein the density of the nano-particles and micro-particles is 1.50 g/ml or less.
10. The liquid of claim 1 , wherein the oil/water emulsion is incubated at about 30-150° C.
11. The liquid of claim 1 , wherein the oil/water emulsion is incubated for about 5-200 minutes.
12. The liquid of claim 1 , wherein the at least one surfactant comprises anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants or combinations thereof.
13. The liquid of claim 1 , wherein the at least one curing agent comprises isophorone diamine, boron tri-fluoride derivatives, imidazolines, mercaptans, hydrazides, polyamides, functional resins, mono ethanol amine, benzyl dimethylamine, lewis acids, tertiary amines, cycloaliphatic amines, amidoamines, aliphatic amines, aromatic amines, isophorone, imidazoles, sulfide, amides or their derivatives.
14. The liquid of claim 1 , wherein the pH control agent comprises sodium hydroxide, potassium hydroxide, or combinations thereof.
15. The liquid of claim 1 , wherein the oil/water emulsion further comprises a viscosity enhancer.
16. The liquid of claim 15 , wherein the viscosity enhancer comprises calcium carbonate nanoparticles, silicate nanoparticles, or water-soluble polymers comprising polyacrylamide or polyvinyl alcohol.