1. A microemulsion for reducing the viscosity of heavy and extra-heavy crude oils, said microemulsion comprising a surfactant, a co-surfactant and brine.
2. The microemulsion of claim 1, wherein said surfactant is selected from the group consisting of an alkylsulfonate of alkylamine, an alkylsulfonate of a polyalkylamine, an alkanolamides, an alkanolamine, a glycolester, a monoester of ethyleneglycol, a polyoxyethylene alcohol, a polyoxyethylene alkylamine, a polyxyethylene alkylamide, a polyglycerol ester, a polyoxyalkylene polyol-ester, and a sodium carboxymethylcelulose.
3. The microemulsion of claim 1, wherein said surfactant is nonyl phenol ethoxylate.
4. The microemulsion of claim 1, wherein said surfactant is sodium dodecyl-benzene-sulfonate.
5. The microemulsion of claim 1, wherein said co-surfactant is a medium chain length primary alcohol having 1-15 carbon atoms, a propylene glycol or an alkanolamine.
6. The microemulsion of claim 1, wherein said co-surfactant is a primary alcohol.
7. The microemulsion of claim 1, wherein said brine comprises between 50,000 and 80,000 ppm salt in its formulation.
8. The microemulsion of claim 1, wherein the amount of said surfactant is between 45 and 80 wt. %, and the amount of said primary alcohol is between 10 and 30 wt. % based on the total weight of the surfactant and cosurfactant.
9. A process for the preparation of a micro emulsion to reduce the viscosity of heavy and extra-heavy crude oils, which comprises mixing a surfactant, a co-surfactant and brine, stirring said mixture to form a microemulsion, and cooling said micro emulsion.
10. The process of claim 9, wherein said surfactant and co-surfactant are mixed in a first stage to form a first mixture, and said brine and said first mixture are combined in a second stage.
11. The process of claim 10, wherein the agitation time for mixing said surfactant with said co-surfactant in said first stage is between 10 and 50 min.
12. The process of claim 11, wherein the mixing of said surfactant with said co-surfactant is conducted at an agitation speed of between 200-800 rpm.
13. The process of claim 9, wherein said microemulsion is cooled for a period of 1 to 3 h in a covered container.
14. The process for reducing viscosity of heavy and extra-heavy crude oils, which comprises mixing the microemulsion of claim 1 with said crude oil at a concentration of 500 to 50,000 ppm by wt. based on said crude oil.
15. The process of claim 14, wherein said microemulsion is mixed with said crude oil at a concentration of 5000 to about 10,000 ppm.
16. A process for the secondary recovery of crude oil from a well comprising the steps of
injecting the microemulsion of claim 1 into the well to form an emulsion with the crude oil, and
recovering the resulting crude oil emulsion from the well.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A permeability measurement apparatus comprising:
a magnetic field generation means applying an alternating magnetic field having a predetermined frequency to a magnetic substance to be measured;
a probe needle placed in proximity or in contact to a microscopic area of the magnetic substance to be measured to which the alternating magnetic field is applied;
a resonator including a coil wound on the probe needle, and generating a magnetic field having a resonant frequency higher than the frequency of the alternating magnetic field applied on the microscopic area having the probe needle in proximity or in contact thereto, and having inductance of the coil varied as permeability in the microscopic area varies; and
a measurement means measuring the permeability of the microscopic area of the magnetic substance to be measured based on the variation of the resonant frequency of the resonator according to the variation of the coil inductance.
2. The permeability measurement apparatus according to claim 1,
wherein the measurement means includes:
an oscillation means outputting an oscillation signal having a frequency according to the variation of the resonant frequency;
a demodulation means outputting a voltage signal demodulated from the oscillation signal; and
a detection means detecting linear permeability from a direct current component of the voltage signal.
3. The permeability measurement apparatus according to claim 1,
wherein the measurement means includes:
an oscillation means outputting an oscillation signal having a frequency according to the variation of the resonant frequency;
a demodulation means outputting a voltage signal demodulated from the oscillation signal; and
a detection means detecting nonlinear permeability from an alternating current component of the voltage signal.
4. The permeability measurement apparatus according to claim 3,
wherein the detection means measures lowest-order nonlinear permeability from a predetermined frequency component of the alternating magnetic field among the alternating current component of the voltage signal, and
measures higher-order nonlinear permeability than the lowest order based on a frequency component of integer multiple of two or more of the predetermined frequency of the alternating magnetic field.
5. The permeability measurement apparatus according to claim 4,
wherein the detection means measures a direction of magnetization in the microscopic area, based on a sign of nonlinear permeability in an odd-rank tensor including the lowest-order nonlinear permeability.
6. The permeability measurement apparatus according to claim 4, further comprising:
a scanning means moving the probe needle relatively to the magnetic substance to be measured; and
a gap control means performing non-contact control so that a gap between the probe needle and the magnetic substance to be measured becomes a certain distance, based on a measurement level of the high-order nonlinear permeability detected by the detection means,
wherein the detection means measures nonlinear permeability of lower order than the high-order nonlinear permeability.
7. The permeability measurement apparatus according to claim 4,
wherein the magnetic field generation means applies a rotating magnetic field having a magnetic field direction successively rotating in a predetermined plane.
8. The permeability measurement apparatus according to claim 1,
wherein the probe needle includes an extension portion being connected to the probe needle and extending substantially in parallel to the probe needle to a position in the proximity of the magnetic substance to be measured.
9. The permeability measurement apparatus according to claim 4,
wherein the detection means further measures a magnitude and a direction of the magnetic field in the microscopic area of the magnetic substance to be measured, based on the measured nonlinear permeability.
10. An electron spin resonance apparatus comprising:
a magnetic field generation means applying an alternating magnetic field having a predetermined frequency and a direct-current magnetic field in superposition to a magnetic substance to be measured;
a probe needle placed in proximity or in contact to a microscopic area of the magnetic substance to be measured;
a resonator including a coil wound on the probe needle, and generating a magnetic field having a predetermined resonant frequency applied on the microscopic area having the probe needle in proximity or in contact thereto, and at least having inductance of the coil varied due to electron spin resonance generated in the microscopic area; and
a measurement means for measuring electron spin resonance generated in the microscopic area of the magnetic substance to be measured based on the variation of the resonant frequency or the resonant level of the resonator.