CN116120908B - A kind of preparation method of ultra-heavy oil emulsified viscosity-reducing microemulsion - Google Patents

Abstract

The invention relates to the technical field of thick oil emulsification and viscosity reduction, and discloses a preparation method of super heavy oil emulsification and viscosity reduction microemulsion. The preparation method is as follows: (1) first mix diesel oil with super heavy oil (0.3~1.5):1, and Keep the temperature in a water bath at 55°C, let it stand for 15 minutes, and then use a stirrer to stir for 20 minutes under the condition of 1200~1500r/min; Stir evenly at ~30°C, stirring speed 400~800r/min, and let it stand for 5 hours until the surfactant is completely dissolved in water; (3) Add the prepared 0.5% octane to the mixed system of diesel oil and super heavy oil Phenol polyoxyethylene ether-10 solution, and stirred at a constant temperature of 55°C and a stirring speed of 1200-1500r/min for 20 minutes to obtain an emulsified and reduced-viscosity oil-in-water microemulsion. The particle size of the emulsion droplet ranges from 100 to 150 μm. The microemulsion surfactant has less dosage, easy-to-obtain raw materials, simple preparation process, and the highest viscosity reduction rate can reach 99.81%, which can achieve the beneficial effect of improving oil recovery.

Description

A kind of preparation method of ultra-heavy oil emulsified viscosity-reducing microemulsion

technical field

The invention relates to the technical field of viscosity reduction of heavy oil, in particular to a preparation method of super heavy oil emulsified viscosity reduction microemulsion.

Background technique

As one of the four major heavy oil producing countries in the world, my country is rich in heavy oil resources. However, due to the characteristics of deep burial, high formation temperature, high pressure, high viscosity, high freezing point, and poor fluidity of ultra-heavy oil reservoirs, it is difficult to develop ultra-heavy oil and the oil recovery rate is low. For example, the crude oil from Tahe Oilfield and Liaohe Oilfield in China is a typical super-heavy oil reservoir, with a viscosity as high as 5×10 ⁴ ~3×10 ⁶ mPa·s. Due to the high flow resistance of ultra-heavy oil, it is difficult to flow from the reservoir into the wellbore or lift from the wellbore to the ground, so there are still many difficulties in the production of ultra-heavy oil. Among the many ultra-heavy oil production methods, the emulsification viscosity reduction method has been paid more and more attention by researchers due to its advantages of greenness, high efficiency, non-toxicity, stability, and low-carbon economy. Significance.

At present, the emulsification and viscosity reduction method is one of the most effective ways to recover super heavy oil. In order to achieve high-efficiency viscosity reduction in super-heavy oil emulsification, it is first necessary to formulate and select a suitable surfactant type, injection method and injection volume according to the composition structure, physical and chemical properties and formation conditions of super-heavy oil. The properties of ultra-heavy oil are different from conventional heavy oil in that there is less straight-run distillate, high viscosity, high content of asphaltenes, and more heavy components. Its properties are similar to atmospheric residue or even vacuum residue, and its viscosity mainly It is determined by the colloid and asphaltene content of the heavy component, so the conventional emulsification viscosity reduction method has no obvious effect on its viscosity reduction. With the deepening of mining, the formation conditions become worse, and the pressure and temperature of formation water rise. The microemulsion prepared by the conventional emulsification viscosity reduction method cannot withstand the harsh formation environment for a long time, resulting in poor viscosity reduction effect of super heavy oil. , the mining efficiency is not high. In summary, the present invention proposes a method for preparing super-heavy oil emulsified viscosity-reducing microemulsion.

Contents of the invention

The present invention aims at the difficult problems of domestic ultra-heavy oil exploitation and the like, and proposes a preparation method of super-heavy oil emulsification and viscosity-reducing microemulsion. The emulsified viscosity-reduced microemulsion prepared by the invention has the advantages of easy-to-obtain raw materials, simple preparation process, no by-products, safety and environmental protection, high emulsified viscosity-reduced rate, and the like.

The present invention is achieved through the following technical solutions:

A nonionic surfactant used in a method for preparing a super-heavy oil emulsified viscosity-reducing microemulsion is octylphenol polyoxyethylene ether-10, and the molecular structure formula of the nonionic surfactant is shown in FIG. 1 .

The nonionic surfactant has high stability, good solubility in various solvents, no strong adsorption on the solid surface, and good use effect.

The purpose of the invention is to disclose a method for preparing a super-heavy oil emulsified viscosity-reducing microemulsion, the specific steps are as follows:

(1) Add a certain amount of diesel oil and super heavy oil to the beaker, let it stand at a temperature of 55°C for 15 minutes, and use a stirrer to stir at 1200~1500r/min for 20 minutes to obtain a blended thin heavy oil;

(2) Add deionized water and quantitative octylphenol ethoxylate-10 to another beaker, and stir evenly at 20~30°C at a stirring speed of 400~800r/min, and let stand for 5h until the surface The active agent is completely dissolved in water to obtain an aqueous solution of octylphenol polyoxyethylene ether-10;

(3) Add the prepared octylphenol polyoxyethylene ether-10 solution to the mixed system of diesel oil and super heavy oil, and stir for 20 minutes at a constant temperature of 55°C and a stirring speed of 1200-1500r/min to obtain emulsified viscosity-reducing micro lotion.

Preferably according to the present invention, in step (1), the mass ratio of diesel oil to super heavy oil is 1.5:1.

Further preferably, in step (1), the mass ratio of diesel to super heavy oil is (0.3-0.5):1.

The present invention finds in experiments that the selection of monomers of the present invention, the proportioning ratio of monomers and the addition method have a good effect on reducing the viscosity of super heavy oil. When the mass ratio of diesel oil to super heavy oil is 1.5:1, the super thick The viscosity reduction rate of oil is 95~97%. When the mass ratio of diesel oil to super heavy oil (0.3~0.5): 1, the viscosity reduction efficiency of super heavy oil is the best, which can reach 98~99.5%. However, when the mass ratio of diesel oil to super heavy oil is less than 0.3:1, the viscosity reduction rate of super heavy oil drops to 88~91%, compared with the viscosity reduction effect of diesel oil to super heavy oil mass ratio (0.3~0.5):1 lower.

Preferably, according to the present invention, in step (2), the mass fraction of the octylphenol polyoxyethylene ether-10 solution is 0.5%.

Preferably according to the present invention, in step (3), the oil-water ratio of the mixed system of diesel oil and super heavy oil and octylphenol polyoxyethylene ether-10 is 3:7.

Technical characteristics and advantages of the present invention:

The preparation method of the ultra-heavy oil emulsified viscosity-reducing microemulsion of the present invention has easy-to-obtain raw materials, simple preparation process, less addition of surfactant, and good effect of reducing the viscosity of the super-heavy oil. Due to the large amount of asphaltenes and colloids in super heavy oil, asphaltenes contain functional groups such as carboxyl, pyrrolyl, pyridyl, thienyl, and sulfite, which are composed of heteroatoms such as N, O, and S. Hydrogen bonds, aromatic condensed ring plane accumulation, and the polar interaction force of each functional group together result in the high viscosity state of super heavy oil, which makes it more difficult to reduce viscosity than conventional crude oil and ordinary heavy oil, resulting in difficulties in production. In the present invention, the non-ionic surfactant octylphenol polyoxyethylene ether-10 is used as a monomer, and it is evenly mixed with a diesel super heavy oil mixing system to prepare an emulsified viscosity-reducing microemulsion, which can effectively reduce the viscosity of the super heavy oil to achieve Beneficial effects of enhanced oil recovery.

Description of drawings

Purpose of the drawings: In order to more clearly illustrate the embodiments and technical solutions of the present invention, the following will briefly mark and introduce the drawings required for the embodiments.

Fig. 1 is the molecular structural formula diagram of nonionic surfactant octylphenol polyoxyethylene ether-10.

Fig. 2 is an experimental data diagram for evaluating the viscosity-reducing effect of the emulsified viscosity-reducing microemulsion in each embodiment.

Fig. 3 is a schematic diagram of the plate rotor system of Anton Par MCR302 rheometer and a viscosity-temperature curve of super heavy oil.

Fig. 4 is a schematic diagram of the coaxial cylinder system structure of Anton Par MCR302 rheometer and a viscosity-shear curve of ultra-heavy oil.

Fig. 5 is a graph showing the microscopic observation results of emulsified viscosity-reducing microemulsion droplets.

Figure 6 is a comparison chart of the effect of super heavy oil emulsification and viscosity reduction microemulsion.

Implementation

In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below in conjunction with the drawings in one or more embodiments of this specification Obviously, the described embodiments are only a part of the description, not all of them. Based on one or more embodiments of the description, other embodiments obtained by those of ordinary skill in the art without creative work , should all belong to the scope of protection of the embodiments of this specification.

Embodiment 1: pure diesel oil, super heavy oil, surfactant are mixed simultaneously

(1) Pour 2.5ml of octylphenol polyoxyethylene ether-10 into deionized water, stir at 20~30°C, stir at a speed of 500r/min, stir evenly for 10min, and let it stand for 5h until the surfactant is completely dissolve in water;

(2) Set the mass ratio of diesel oil to super heavy oil at 1.5:1, take 45ml of pure diesel oil, 30ml of super heavy oil, 175ml of octylphenol polyoxyethylene ether-10 solution, and set the oil-water ratio to 3:7, and set Put it in a 500ml beaker, and start stirring after standing in a water bath constant temperature tank for 15 minutes. It was stirred with HJ-5 multi-functional stirrer, the stirring speed was 1500r/min, the stirring time was 20min, and the constant temperature was 55°C.

Embodiment 2: Mix pure diesel oil and super heavy oil with surfactant after being diluted (1.5:1)

(1) Pour 2.5ml of octylphenol polyoxyethylene ether-10 into deionized water, stir at 20~30°C, stir at a speed of 500r/min, stir evenly for 10min, and let it stand for 5h until the surfactant is completely dissolve in water;

(2) Set the mass ratio of diesel oil to super heavy oil at 1.5:1, take 45ml of pure diesel oil and 30ml of super heavy oil, put the two in a 500ml beaker and let them stand in a water bath constant temperature tank for 15min, then use HJ- 5. The multi-functional stirrer stirs the diesel super heavy oil mixed system, the stirring speed is 1500r/min, the stirring time is 10min, and the constant temperature is 55°C;

(3) Add 175ml of octylphenol polyoxyethylene ether-10 solution with a mass fraction of 0.5% into the mixed system of diesel oil and super heavy oil, the oil-water ratio is 3:7, let it stand at a constant temperature of 55°C for 10 minutes, and use HJ-5 Stir with a multifunctional stirrer, the stirring speed is 1500r/min, and the stirring time is 20min.

Example 3: polymer diesel oil, super heavy oil mixed with thin (0.5:1) and mixed with surfactant

(1) Pour 2.5ml of octylphenol polyoxyethylene ether-10 into deionized water, stir at 20~30°C, stir at a speed of 500r/min, stir evenly for 10min, and let it stand for 5h until the surfactant is completely dissolve in water;

(2) Set the mass ratio of diesel oil to super heavy oil at 0.5:1, take the polymer as oil-soluble polyalphaolefin, prepare a polymer diesel solution with a concentration range of 60-1000ppm, and let it stand for 3 days until the polymer is completely dissolved After soaking in pure diesel oil, take a sample of 30ml and 60ml of super heavy oil, put the two in a 500ml beaker and let it stand in a water bath constant temperature tank for 15min, then use HJ-5 multifunctional mixer to mix diesel super heavy oil The system is stirred, the stirring speed is 1500r/min, the stirring time is 10min, and the constant temperature is 55°C;

(3) Add 210ml of octylphenol polyoxyethylene ether-10 solution with a mass fraction of 0.5% into the mixed system of polymer diesel and super heavy oil, the oil-water ratio is 3:7, let it stand at a constant temperature of 55°C for 10min, and use HJ Stir with -5 multifunctional stirrer, the stirring speed is 1500r/min, and the stirring time is 20min.

Embodiment 4: Mix pure diesel oil and super heavy oil with surfactant after being mixed with thin (0.5:1)

(1) Pour 2.5ml of octylphenol polyoxyethylene ether-10 into deionized water, stir at 20~30°C, stir at a speed of 500r/min, stir evenly for 10min, and let it stand for 5h until the surfactant is completely dissolve in water;

(2) Set the mass ratio of diesel oil to super heavy oil at 0.5:1, take 30ml of pure diesel oil and 60ml of super heavy oil, put the two in a 500ml beaker and let them stand in a water bath constant temperature tank for 15min, then use HJ- 5. The multi-functional stirrer stirs the diesel super heavy oil mixed system, the stirring speed is 1500r/min, the stirring time is 10min, and the constant temperature is 55°C;

(3) Add 210ml of octylphenol polyoxyethylene ether-10 solution with a mass fraction of 0.5% to the mixed system of diesel oil and super heavy oil, let it stand at a constant temperature of 55°C for 10 minutes, and stir it with a HJ-5 multifunctional agitator. The stirring speed is 1500r/min, and the stirring time is 20min.

Performance Testing

For each of the above examples, the Anton Par MCR302 rotational rheometer (coaxial cylinder system) produced by Austria Anton Paar was used to evaluate the viscosity-reducing effect of the emulsified viscosity-reducing microemulsion prepared in each example. The experimental conditions were temperature T =40°C, γ =5s ^-1 . When evaluating the viscosity-reducing effect of the prepared emulsified viscosity-reducing microemulsion, the viscosity-reducing rate can be expressed, and its calculation expression is: R _VR =(( μ ₀ - μ )/ μ )×100%.

where: R _VR is the viscosity reduction rate, %; μ _o is the viscosity of super heavy oil at 40°C, mPa∙s; μ is the measured viscosity of super heavy oil emulsified viscosity-reducing microemulsion at 40°C, mPa∙s .

The evaluation data of the viscosity-reducing effect of the emulsified viscosity-reducing microemulsion in each embodiment are shown in Fig. 2 .

(1) According to the test and experimental results of Example 1, it was found that a good emulsified viscosity-reducing microemulsion could not be formed, and the remaining part of the super-heavy oil was still attached to the bottom of the beaker;

(2) According to the test and experimental results of Example 2, it is found that emulsified viscosity-reducing microemulsion can be formed, and the viscosity-shearing experiment at 40°C shows that the viscosity of super-heavy oil is 6040 mPa∙s, and the viscosity-reducing efficiency is 98.20%;

(3) After testing and experimental results, it was found that Example 3 could form a good emulsified viscosity-reducing microemulsion, and the viscosity-shearing experiment at 40°C showed that the viscosity of the super-heavy oil was 1015 mPa∙s, and the viscosity-reducing effect was good. The viscosity-reducing efficiency was 99.71%;

(4) According to the test and experimental results of Example 4, it is found that a good emulsified viscosity-reducing microemulsion can be formed, and the viscosity-shearing experiment at 40°C shows that the viscosity of super-heavy oil is 658mPa∙s, and its viscosity-reducing efficiency is 99.81%. works well.

product characterization

1. Macro viscosity and temperature test of super heavy oil

Anton Par MCR302 rotational rheometer produced by Anton Paar Company in Austria (plate rotor system, plate rotor radius R = 12.50mm) was used, at shear rate γ =5s ^-1 , temperature T = 40~100°C (heating), Under the condition of heating up 3°C/min, the corresponding shear stress τ and shear viscosity η _p ( T ) of super heavy oil at different temperatures were tested, as shown in Fig. 3 .

2. Macro visco-shear test of ultra-heavy oil

The Anton Par MCR302 rotational rheometer (coaxial cylinder system, inner domain radius r _i =13.327mm, rotational test mold radius r _e =14.450mm, mold height I =40.008mm) produced by Anton Paar Company in Austria is used, as As shown in Fig. 4, under the condition of shear viscosity γ =0.1~800s ^-1 and temperature T = 100℃, the corresponding shear stress τ and shear viscosity η _s ( γ ) of super heavy oil are obtained. The test temperature is 100°C because the viscosity of super heavy oil is extremely high at 40°C, which is 352000mPa∙s. It is not feasible to use the coaxial cylinder system for testing, but the viscosity-shear curve of super heavy oil at 100°C can clearly observe the Super heavy oil exhibits typical non-Newtonian fluid characteristics and has pseudoplasticity.

3. Microscopic observation test of emulsified viscosity-reducing microemulsion

The prepared emulsified viscosity-reducing microemulsion was prepared with a DM2700P polarized electron microscope from Leica Instruments Co., Ltd. The microscopic morphology of the droplets was observed at a magnification of 40 times. It can be observed that the microemulsion is an oil-in-water emulsion. The microscopic observation results of the microemulsion are shown in Figure 5. The particle size of the microemulsion ranges from 100 to 150 μm.

4. Emulsification and viscosity reduction evaluation of super heavy oil

The Anton Par MCR302 rotational rheometer (coaxial cylinder system, inner domain radius r _i =13.327mm, rotational test mold radius r _e =14.450mm, mold height I =40.008mm) produced by Anton Paar Company in Austria was used to shear The shear stress τ and shear viscosity η _e ( γ ) corresponding to the ultra-heavy oil emulsified viscosity-reducing microemulsion at different shear rates were obtained by measuring the shear viscosity at γ =0.1~1000s ^-1 and the temperature T = 40° C (As shown in Figure 6), the evaluation of its viscosity-reducing effect can be expressed by the viscosity-reducing rate R _VR , and the experimental data results are shown in Figure 2.

The preferred embodiments of the present invention have been described in detail above, however, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the disclosed content of the present invention. All belong to the protection scope of the present invention.

Claims (3)

1. a preparation method of super thick oil emulsified viscosity-reducing microemulsion, is characterized in that, the concrete steps of described preparation method are as follows: (1) Add a certain amount of diesel oil and super heavy oil into the beaker, the mass ratio of diesel oil to super heavy oil is (0.3~0.5): 1, and let it stand for 15 minutes at a temperature of 55°C, and use a stirrer to set the temperature at 1200~ Stir for 20 minutes under the condition of 1500r/min to obtain mixed thin thick oil; (2) Add deionized water and quantitative octylphenol polyoxyethylene ether-10 to another beaker. The mass fraction of the octanephenol polyoxyethylene ether-10 solution is 0.5%. Stir evenly at a stirring speed of 400~800r/min, and let it stand for 5 hours until the surfactant is completely dissolved in water to obtain an aqueous solution of octylphenol polyoxyethylene ether-10; (3) Add the prepared Octylphenol Polyoxyethylene Ether-10 solution to the diesel and super heavy oil mixed system, the diesel and super heavy oil mixed system and 0.5% Octylphenol Polyoxyethylene Ether-10 The mixed oil-water ratio of the solution is 3:7, and it is stirred for 20 minutes at a constant temperature of 55°C and a stirring speed of 1200-1500r/min to obtain an emulsified viscosity-reducing microemulsion. 2. A method for preparing an ultra-heavy oil emulsified viscosity-reducing microemulsion as claimed in claim 1, wherein the particle size range of the ultra-heavy oil emulsified viscosity-reducing microemulsion is 100-150 μm. 3. A method for preparing a super-heavy oil emulsified viscosity-reducing microemulsion as claimed in claim 1, wherein the super-heavy oil emulsified viscosity-reducing microemulsion is at temperature T = 40°C, γ =0.1~1000s ^{- 1} , the viscosity decreased to 658 mPa∙s, and the viscosity reduction rate was as high as 99.81%.

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