Dual-functional breaker for hybrid fluids of viscoelastic surfactant and polymer
View Patent ↗Incorporating water-based polymer breakers, such as oxidizers, enzymes and/or acids, into a mixture of an oil and oil-soluble surfactants creates an emulsion that can then perform as a dual-functional breaker for reducing the viscosity of hybrid fluids gelled with both a viscoelastic surfactant (VES) and a polymer. The outer phase of the dual-functional breaker emulsion is oil, e.g. a mineral oil, containing an oil-soluble surfactant that will, over time and with heat, break the VES portion of the gel. As it does so, the polymer breaker in the internal aqueous phase will be released to then break the polymer portion of the gel. The polymer breaker will not start to break the polymer gel before the oil-soluble surfactant starts to break the VES gel. The overall breaking using the emulsion is slower as compared to introducing the polymer breaker and the oil-soluble surfactant in a non-emulsified form.
1. A dual-functional breaker emulsion comprising:
an oil external phase comprising an oil-soluble surfactant, and
a water internal phase comprising a water-soluble polymer breaker.
2. The dual-functional breaker emulsion of claim 1 where the volume ratio of oil external phase to oil-soluble surfactant to water internal phase is:
about 55 to about 85 vol % oil external phase to
about 0.5 to about 10 vol % oil-soluble surfactant to
about 5 to about 44.5 vol % water internal phase.
3. The dual-functional breaker emulsion of claim 2 where the concentration of water-soluble polymer breaker in the water internal phase ranges from about 5 to about 50 weight %.
4. The dual-functional breaker emulsion of claim 1 where the oil external phase is mineral oil.
5. The dual-functional breaker emulsion of claim 1 where the oil-soluble surfactant is selected from the group consisting of sorbitan fatty acid esters, saponified hard oils, saponified hydrogenated fatty acid oils, long chain alcohols, long chain fatty acid alcohols, long chain fatty amines, long chain sulfates, long chain sulfonates, phosopholipids, lignins, and combinations thereof.
6. The dual-functional breaker emulsion of claim 1 where the water-soluble polymer breaker is selected from the group consisting of ammonium persulfate, sodium persulfate, potassium persulfate, sodium peroxide, barium peroxide, hydrogen peroxide, magnesium peroxide, potassium peroxide, sodium perborate, potassium perborate, potassium permanganate, sodium permanganate, percarbonate, bromate, perphosphate, amylase, hemi-cellulase, acetic acid, formic acid and combinations thereof.
7. A dual-functional breaker emulsion comprising:
an oil external phase comprising an oil-soluble surfactant, and
a water internal phase comprising a water-soluble polymer breaker;
where:
the oil external phase is mineral oil;
the oil-soluble surfactant is selected from the group consisting of sorbitan fatty acid esters, saponified hard oils, saponified hydrogenated fatty acid oils, long chain alcohols, long chain fatty acid alcohols, long chain fatty amines, long chain sulfates, long chain sulfonates, phosopholipids, lignins, and combinations thereof; and
the water-soluble polymer breaker is selected from the group consisting of ammonium persulfate, sodium persulfate, potassium persulfate, sodium peroxide, barium peroxide, hydrogen peroxide, magnesium peroxide, potassium peroxide, sodium perborate, potassium perborate, potassium permanganate, sodium permanganate, percarbonate, bromate, perphosphate, amylase, hemi-cellulase, acetic acid, formic acid and combinations thereof.
8. The dual-functional breaker emulsion of claim 7 where the volume ratio of oil external phase to oil-soluble surfactant to water internal phase is:
about 55 to about 85 vol % oil external phase to
about 0.5 to about 10 vol % oil-soluble surfactant to
about 5 to about 44.5 vol % water internal phase.
9. The dual-functional breaker emulsion of claim 8 where the concentration of water-soluble oxidizer in the water internal phase ranges from about 5 to about 50 weight %.
10. A dual-functional breaker emulsion comprising:
an oil external phase comprising an oil-soluble surfactant, and
a water internal phase comprising a water-soluble polymer breaker;
where:
the oil external phase is mineral oil;
the oil-soluble surfactant is selected from the group consisting of sorbitan fatty acid esters, saponified hard oils, saponified hydrogenated fatty acid oils, long chain alcohols, long chain fatty acid alcohols, long chain fatty amines, long chain sulfates, long chain sulfonates, phosopholipids, lignins, and combinations thereof; and
the water-soluble polymer breaker is selected from the group consisting of ammonium persulfate, sodium persulfate, potassium persulfate, sodium peroxide, barium peroxide, hydrogen peroxide, magnesium peroxide, potassium peroxide, sodium perborate, potassium perborate, potassium permanganate, sodium permanganate, percarbonate, bromate, perphosphate, amylase, hemi-cellulase, acetic acid, formic acid and combinations thereof,
where the volume ratio of oil external phase to oil-soluble surfactant to water internal phase is:
about 55 to about 85 vol % oil external phase to
about 0.5 to about 10 vol % oil-soluble surfactant to
about 5 to about 44.5 vol % water internal phase; and
where the concentration of water-soluble oxidizer in the water internal phase ranges from about 5 to about 50 weight %.