Patent ID: 12241022

DETAILED DESCRIPTION

The particulars shown herein are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present disclosure only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of various embodiments of the disclosure. In this regard, no attempt is made to show structural details of the disclosure in more detail than is necessary for the fundamental understanding of the disclosure, the description taken with the drawings making apparent to those skilled in the art how the several forms of the disclosure may be embodied in practice.

The following definitions and explanations are meant and intended to be controlling in any future construction unless clearly and unambiguously modified in the following examples or when application of the meaning renders any construction meaningless or essentially meaningless. In cases where the construction of the term would render it meaningless or essentially meaningless, the definition should be taken from Webster's Dictionary 3rdEdition.

Nano- and micro-particles (NMP) can be utilized as proppants to enhance the conductivity of microfractures and fluid-loss-control additives for hydraulic fracturing operations. In an embodiment, nano-, micro-, or a mixture of nano- and micro-particles can be used.

In an embodiment, the NMP are made from an oil/water emulsion. In an embodiment, the emulsion is made by mixing a liquid solvent, at least one surfactant, a particle-forming compound, and at least one curing agent together. The particle-forming compound and the curing agents are mixed together to form the oil phase in the oil/water emulsion. After curing, the “oil” droplets turn into NMP.

In an embodiment, the liquid solvent comprises water, seawater, brine containing monovalent, divalent, and multivalent salts, an alcohol such as ethanol, propanol, butanol, or combinations thereof.

In an embodiment, the surfactant comprises anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants or combinations thereof.

In an embodiment, the particle-forming compound can be but is not limited to aliphatic epoxides, anhydrides, glycidyl amine epoxide, cycloaliphatic epoxides, epoxy functional resins, polyurethane resins, phenol-formaldehyde resin, bis-phenol A diglycidyl ether, poly glycidyl ethers, acrylic resin, glycidyl ethers, bis-phenol F diglycidyl ethernovalac resins, or combinations thereof.

In an embodiment, the curing agent can be but is not limited to 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, and their derivatives.

If desired, acid or alkali pH control agents can be added to the liquid solvent. In an embodiment, the pH control agents can be selected from but not limited to mineral acids such as sodium hydroxide, potassium hydroxide, calcium hydroxide, and combinations thereof.

If desired, viscosity enhancers can be added to the liquid solvent. In an embodiment, the viscosity enhancers can be selected from but not limited to nanoparticles such as calcium carbonate nanoparticles and silicate nanoparticles, and water-soluble polymers such as polyacrylamide and polyvinyl alcohol.

In an embodiment, NMP are formed by mixing the liquid solvent, at least one surfactant, a particle-forming compound, and at least one curing agent together for 3-15 minutes to form an oil/water emulsion and then allowed to stand undisturbed in a water bath at 30-150° C. for 5-200 minutes. In an embodiment, they are mixed together for about 10 minutes. In an embodiment, the temperature is 60° C. In an embodiment, the emulsion is allowed to stand in the water bath for 60 minutes. In an embodiment, seawater is used as liquid solvent. In an embodiment, alkali is added to adjust the pH. In an embodiment, the pH is adjusted to at least about 12. This method results in formation of particles across a broad size range from nanoscale to microscale.

The NMP serve multiple functions in hydraulic fracturing operations. In an embodiment, NMP can be added to the pad and/or fracturing fluids to increase the conductivity of nano- and micro-fractures. In an embodiment, NMP are used to complement a primary proppant functioning to keep the main fractures open, as depicted inFIG.1. In an embodiment, NMP additionally function as a fluid-loss-control additive.

The density of the nanoparticles (diameter<1 μm) and microparticles (diameter≤100 μm) made through the disclosed method is no more than 1.50 g/ml and thus far lower than nano- and micro-particle proppants described in the prior art, for example, silica flour and ceramic microparticle proppants and silicon oxide, calcium oxide, and aluminum oxide nanoparticles produced from fly ash. The low density permits NMP to be transported far in the hydraulic fracture with low settling rate.

In addition, NMP are deformable. This prevents the NMP from being crushed when fractures attempt to close after the injection has stopped and enhances flushing of NMP out of nano- and micro-fractures.

EXAMPLES

Tween™ 20 is a polyoxyethyene (20) sorbitan monolurate with a registered trademark of Croda International plc, containing Alkoxylate.

Hostafrac SF14413 is a product of Clariant Corporation. 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.

Max CLR™ is a trademark of Polymer Composites Corporation.

Max CLR™ A is a modified bisphenol A epoxy resin, 90-100% by weight phenol, 4-(1-methylethylidene) Bis, Polymer with (Chloromethane) Oxerane, 1-5% by weight epoxidize diluent reactive, 0-10% by weight epoxidize cresylglyciderether modified, and 0.1-0.5% by weight non-silicone additive.

Max CLR™ B is an amine modified curing agent. It contains about between 5-15% by weight benzyl alcohol, 15-35% by weight isophoromediamine adduct, and 50-60% by weight aliphatic amine adduct.

Example 1

The liquid for making the oil/water emulsion to form the NMP is shown in Table 1. Adding pH control agent with a weight percentage of 1.44 wt, obtained a pH of 12.45. The liquid was mixed for 5 minutes to form an emulsion and then allowed to stand undisturbed in water bath at 60° C. for 1 hour to react to form NMP. The NMP formed are shown inFIG.2. The particle size distribution was determined by Mastersizer 3000 laser particle size analyzer. The size distribution results are shown inFIG.3. Microparticles were formed having sizes ranging from a diameter of 1 μm to <100 μm. Nanoparticles were formed having sizes of a diameter of <1 μm.

TABLE 1Liquid componentsWeight (g)Wt. %Tween ™ 2032.9Hostafrac SF1441376.7Seawater3129.7pH control agent1.51.4Max CLR ™ A3129.7Max CLR ™ B3129.7

Example 2

The liquid for making the oil/water emulsion to form the NMP is shown in Table 2. The liquid was mixed for 5 minutes to form an emulsion and then allowed to stand undisturbed in a water bath at 60° C. for 1 hour to react to form NMP. The NMP formed are shown inFIG.4. The size distribution results are shown inFIG.5. The size of the particles formed is less than 100 μm.

TABLE 2Liquid componentsWeight (g)Wt. %Tween ™ 2033.7Hostafrac SF1433478.6Seawater3036.8pH control agent1.51.8Epoxy embedding medium3036.8Max HTE B1012.3

Hostafrac SF14334 is a product of Clariant Corporation. <12% by weight “alcohols, C11-14-iso, C13 rich, ethoxylated”, <10% by weight polyoxyethylene monobutyl ether, <5% propylene glycol.

Epoxy embedding medium is a product of Sigma-Aldrich. <=100% by weight “1,2,3-Propanetriol, polymer with 2-(chloromethyl)oxirane”.

Max HTE B is a product of Polymer Composites, Inc. 30-60% by weight 4,4 Methylenebis(cyclohexylamine), 30-50% by weight 3,3(Oxybis(2, 1 ethane-diloxy))bis 1-propanamine.

Example 3

The liquid for making the oil/water emulsion to form the NMP is shown in Table 3. The liquid was mixed for 5 minutes to form an emulsion and then allowed to stand undisturbed in a water bath at 60° C. for 1 hour to react to form NMP. The NMP formed are shown in FIG.6. The size distribution results are shown inFIG.7. The size of the particles formed is less than 100 μm.

TABLE 3Liquid componentsWeight (g)Wt. %Tween ™ 2033.0Hostafrac SF1321376.9Seawater3029.6pH control agent1.51.5Max 1618 Part A3029.6Max 1618 Part B3029.6

Hostafrac SF13213 is a product of Clariant Corporation. ⇐50% by weight proprietary ingredients, ⇐15% by weight solvent naphtha, ⇐10% Ethoxylated alcohol.

Max 1618 is a product of Polymer Composites, Inc.

Max 1618 Part A is an epoxy resin, 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).

Max 1618 Part B is an amine curing agent, 30-60% by weight epoxy adduct, 30-50% by weight 3,3(oxybis(2, 1 ethane-diloxy))bis 1-propanmine.

Example 4

The liquid for making the oil/water emulsion to form the NMP is shown in Table 4. The liquid was mixed for 5 minutes to form an emulsion and then allowed to stand undisturbed in a water bath at 60° C. for 1 hour to react to form NMP. The NMP formed are shown inFIG.8. The size distribution results are shown inFIG.9. The size of the particles formed is less than 100 μm.

TABLE 4Liquid componentsWeight (g)Wt. %Tween ™ 2033.0Hostafrac SF1433476.9Seawater3029.6pH control agent1.51.5Epoxy embedding medium3029.6Max CLR ™ B3029.6

All of the compositions and methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the compositions and methods of this disclosure have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the compositions and methods and in the steps or in the sequence of steps of the methods described herein without departing from the concept, spirit and scope of the disclosure. More specifically, it will be apparent that certain agents which are both chemically related may be substituted for the agents described herein while the same or similar results would be achieved. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the disclosure as defined by the appended claims.