A side-chain polyether amphiphilic polymer demulsifier for super heavy oil, its preparation method and application

Abstract

The present invention provides a side-chain polyether-type amphiphilic polymer demulsifier for super heavy oil, its preparation method and application. The demulsifier has the structure shown in the following formula (I), and its preparation method includes the steps of: adding methyl allyl polyoxyethylene ether into solvent A, heating to the reaction temperature, and adding an initiator solution; then adding butyl acrylate for reaction to obtain the side-chain polyether-type amphiphilic polymer demulsifier for super heavy oil. The demulsifier of the present invention is a copolymer of butyl acrylate and methyl allyl polyoxyethylene ether. The preparation method of this copolymer is simple. Under the conditions of 80 °C, 3 h, and a dosage of 500 ppm, the demulsification effect can reach more than 96%, and the surface tension can be reduced to a minimum of 40 mN / m. The synthesis of the present invention is prepared by a one-pot method, with simple process, and can be regulated by structure and molecular weight to prepare demulsifiers suitable for emulsions of different heavy oils.

Description

Technical Field

[0001] The present invention relates to a side-chain polyether type amphiphilic polymer demulsifier for extra-heavy oil, its preparation method and application, belonging to the field of oilfield chemistry. Background Art

[0002] With the continuous growth of global energy demand, the availability of conventional or easily exploitable crude oil is becoming increasingly limited, and the development of unconventional heavy oil and extra-heavy oil has received extensive attention. However, due to its inherent high viscosity and low fluidity characteristics, combined with a complex reservoir structure, the expected oil recovery process is very challenging. The addition of various oil production aids during oil extraction has continuously increased the water content of the produced fluid from oil wells, making the composition and physical properties of the produced fluid more complex, and the emulsion viscosity is also increasing rapidly. In the process of continuous change of crude oil physical properties, the research and development of new demulsifiers also need to keep up.

[0003] Due to the complex physical properties of crude oil, there are various components and substances inside, and the interaction between them is not clear. Therefore, the demulsification effect of crude oil demulsifiers is not a definite value. For different crude oils, the demulsification effect of the same demulsifier is different. Conversely, for different demulsifiers, the adaptability to different crude oils is also different. When selecting a demulsifier suitable for the corresponding crude oil, a large number of preliminary experiments are required for sample screening. When demulsifying extra-heavy oil with a viscosity of 9.3×10 5 mPa·s at room temperature, when various demulsifiers on the market and prepared in the laboratory are used for demulsification, it is found that the demulsification effect is poor. Under the conditions of 80°C, 3h, and an addition amount of 500 ppm, the average dehydration rate is about 10%, and some demulsifiers have no obvious demulsification effect.

[0004] Therefore, there is an urgent need to synthesize a new demulsifier suitable for extra-heavy oil to solve such problems. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a side-chain polyether type amphiphilic polymer demulsifier for extra-heavy oil, its preparation method and application. The demulsifier of the present invention is a copolymer of butyl acrylate and methallyl polyoxyethylene ether. The preparation method of this copolymer is simple, and under the conditions of 80°C, 3h, and an addition amount of 500 ppm, the demulsification effect can reach more than 96%.

[0006] The technical solution of the present invention is as follows:

[0007] A side-chain polyether type amphiphilic polymer demulsifier for extra-heavy oil, the demulsifier has the structure shown in the following formula (I):

[0008]

[0009] In formula (I), n is an integer from 171 to 173, and x is (0.6 - 1.5)×103 wherein x is an integer from 0 to 10, and y is an integer from 7 to 40.

[0010] According to the present invention, the method for preparing the above-mentioned side-chain polyether amphiphilic polymer ultra-heavy oil demulsifier comprises the following steps:

[0011] Add methallyl polyoxyethylene ether into solvent A, heat up to the reaction temperature, and add the initiator solution; then add butyl acrylate for reaction to obtain the side-chain polyether amphiphilic polymer ultra-heavy oil demulsifier.

[0012] Preferably according to the present invention, the solvent A is acetonitrile; the ratio of the total mass of methallyl polyoxyethylene ether and butyl acrylate to the volume of solvent A is 1 g: 2-5 mL.

[0013] Preferably according to the present invention, the reaction temperature is 65-80 °C, and more preferably 70-75 °C.

[0014] Preferably according to the present invention, the initiator is azobisisobutyronitrile (AIBN) or benzoyl peroxide (BPO); the initiator solution is obtained by dissolving the initiator in solvent B, and the solvent B is the same as solvent A; the concentration of the initiator solution is 0.001-0.01 g / mL.

[0015] Preferably according to the present invention, the mass ratio of methallyl polyoxyethylene ether to butyl acrylate is 6:4 - 2:8, and more preferably 6:4, 5:5, 4:6 or 2:8.

[0016] Preferably according to the present invention, the butyl acrylate is added dropwise into the system, and the dropping time is 20-40 min.

[0017] Preferably according to the present invention, the mass of the initiator is 0.2-1% of the total mass of methallyl polyoxyethylene ether and butyl acrylate.

[0018] Preferably according to the present invention, the reaction is carried out under a nitrogen atmosphere, and the reaction time is 8-15 h.

[0019] Preferably according to the present invention, after the reaction is completed, a post-treatment step is further included, specifically as follows: remove the solvent from the obtained reaction solution, soak the obtained product with ether, white precipitate appears, pour out the supernatant, and vacuum dry at 40-50 °C for 2-4 h to obtain a white powder, which is the side-chain polyether amphiphilic polymer ultra-heavy oil demulsifier.

[0020] According to the present invention, the application of the above-mentioned side-chain polyether amphiphilic polymer ultra-heavy oil demulsifier is used for demulsifying ultra-heavy oil; the viscosity of the ultra-heavy oil at room temperature is 9×10 5 mPa·s - 15×10 5mPa·s. In the present invention, the room temperature refers to 25 ± 5 °C.

[0021] The technical features and beneficial effects of the present invention are as follows:

[0022] 1. Through a large number of experimental screenings, the present invention selects butyl acrylate and methallyl polyoxyethylene ether as monomers to prepare a copolymer demulsifier. As a hydrophilic monomer, methallyl polyoxyethylene ether plays a role in penetrating the oil-water interfacial film in an emulsion with an oil-phase continuous phase. Its presence makes it easier for the polymer to aggregate on the oil-water surface, and at the same time enhances the displacement ability of the polymer for the natural surfactant at the oil-water interface. The presence of butyl acrylate enhances the diffusion ability of the polymer in the continuous phase. It improves the lipophilicity of the polymer, making it easier to diffuse in the oil phase to reach the vicinity of the oil-water interface where the polymer functions. The synergistic effect of the two improves the demulsification effect of the demulsifier. Experiments have shown that the demulsification effect of the demulsifier of the present invention can reach more than 96% under the conditions of 80 °C, 3 h, and a dosage of 500 ppm.

[0023] 2. The synthesis steps of the demulsifier of the present invention are simple. The synthesis process does not require a high-temperature and high-pressure environment, and the monomers have stable properties at normal temperature and pressure, making them easy to store and transport. Therefore, it has good application value. Description of the Drawings

[0024] Figure 1 It is the NMR spectrum of the demulsifier prepared in Example 1.

[0025] Figure 2 It is the demulsification effect curve graph of the demulsifiers prepared in Examples 1-4 and Comparative Examples 2-3.

[0026] Figure 3 It is the demulsification effect photos of the demulsifiers prepared in Examples 1-4 and Comparative Examples 2-3.

[0027] Figure 4 It is the surface activity effect diagram of the demulsifiers prepared in Examples 1-3 and Comparative Examples 2-3. Detailed Description of the Invention

[0028] In order to have a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the technical solutions of the present invention are described in detail below, but it should not be construed as a limitation on the implementable scope of the present invention. The butyl acrylate and methallyl polyoxyethylene ether used in the examples are all obtained through regular commercial channels in the art.

[0029] Example 1

[0030] A preparation method of a side-chain polyether-type amphiphilic polymer ultra-heavy oil demulsifier, comprising the following steps:

[0031] Add 30 g of methyl allyl polyoxyethylene ether and 150 mL of acetonitrile into a three-necked flask. Place the three-necked flask in an electrothermal oil bath with magnetic stirring function and heat it up to 75 °C. Dissolve 0.5 g of AIBN in 100 mL of acetonitrile to prepare an initiator solution. After heating up to 75 °C, add the initiator solution into the three-necked flask. Then, under a nitrogen atmosphere, start to dropwise add 20 g of butyl acrylate, and the dropping time is 30 min. After the dropping is completed, continue to react for 10 h at 75 °C under a nitrogen atmosphere to obtain a milky white translucent liquid. After evaporating acetonitrile with a rotary evaporator, soak the obtained product with ether. Pour off the supernatant liquid, and then put the obtained product into a vacuum drying oven and dry it at 40 °C for 2 h to obtain a white powdery product, which is a side-chain polyether-type amphiphilic polymer demulsifier for super heavy oil, denoted as PEA-64.

[0032] Example 2

[0033] A preparation method of a side-chain polyether-type amphiphilic polymer demulsifier for super heavy oil is as described in Example 1, except that: the mass of methyl allyl polyoxyethylene ether is 25 g, and the mass of butyl acrylate is 25 g. The obtained side-chain polyether-type amphiphilic polymer demulsifier for super heavy oil is denoted as PEA-55.

[0034] Example 3

[0035] A preparation method of a side-chain polyether-type amphiphilic polymer demulsifier for super heavy oil is as described in Example 1, except that: the mass of methyl allyl polyoxyethylene ether is 20 g, and the mass of butyl acrylate is 30 g. The obtained side-chain polyether-type amphiphilic polymer demulsifier for super heavy oil is denoted as PEA-46.

[0036] Example 4

[0037] A preparation method of a side-chain polyether-type amphiphilic polymer demulsifier for super heavy oil is as described in Example 1, except that: the mass of methyl allyl polyoxyethylene ether is 10 g, and the mass of butyl acrylate is 40 g. The obtained side-chain polyether-type amphiphilic polymer demulsifier for super heavy oil is denoted as PEA-28.

[0038] Example 5

[0039] A preparation method of a side-chain polyether-type amphiphilic polymer demulsifier for super heavy oil is as described in Example 3, except that: the mass of AIBN used is 0.1 g.

[0040] Example 6

[0041] A preparation method of a side-chain polyether-type amphiphilic polymer demulsifier for super heavy oil is as described in Example 3, except that: the mass of AIBN used is 0.2 g.

[0042] Example 7

[0043] The preparation method of a side-chain polyether amphiphilic polymer demulsifier for ultra-heavy oil is as described in Example 3, except that the mass of AIBN used is 0.3 g.

[0044] Example 8

[0045] The preparation method of a side-chain polyether amphiphilic polymer demulsifier for ultra-heavy oil is as described in Example 3, except that the mass of AIBN used is 0.4 g.

[0046] Comparative Example 1

[0047] The preparation method of a side-chain polyether amphiphilic polymer demulsifier for ultra-heavy oil is as described in Example 1, except that the mass of methyl allyl polyoxyethylene ether is 5 g and the mass of butyl acrylate is 45 g. The obtained side-chain polyether amphiphilic polymer demulsifier for ultra-heavy oil is denoted as PEA-19, and the demulsification effect of the obtained demulsifier is poor.

[0048] Comparative Example 2

[0049] The preparation method of a side-chain polyether amphiphilic polymer demulsifier for ultra-heavy oil is as described in Example 1, except that the mass of methyl allyl polyoxyethylene ether used is 45 g and the mass of butyl acrylate is 5 g. The obtained side-chain polyether amphiphilic polymer demulsifier for ultra-heavy oil is denoted as PEA-91, and the obtained demulsification effect is relatively poor.

[0050] Comparative Example 3

[0051] The preparation method of a side-chain polyether amphiphilic polymer demulsifier for ultra-heavy oil is as described in Example 1, except that the mass of methyl allyl polyoxyethylene ether used is 40 g and the mass of butyl acrylate is 10 g. The obtained side-chain polyether amphiphilic polymer demulsifier for ultra-heavy oil is denoted as PEA-82, and the demulsification effect is relatively poor.

[0052] Comparative Example 4

[0053] The preparation method of a side-chain polyether amphiphilic polymer demulsifier for ultra-heavy oil is as described in Example 3, except that the mass of AIBN used is 0.8 g, and the demulsification effect of the obtained demulsifier is relatively poor.

[0054] Comparative Example 5

[0055] The preparation method of a side-chain polyether amphiphilic polymer demulsifier for ultra-heavy oil is as described in Example 3, except that the mass of AIBN used is 0.9 g, and the demulsification effect of the obtained demulsifier is relatively poor.

[0056] Comparative Example 6

[0057] The preparation method of a side-chain polyether amphiphilic polymer demulsifier for super heavy oil is as described in Example 3, except that the mass of AIBN used is 1 g, and the demulsification effect of the obtained demulsifier is poor.

[0058] Test Example

[0059] The beneficial effects of the present invention are illustrated by the following experiments:

[0060] 1. Nuclear magnetic resonance characterization

[0061] To identify whether the synthesized polymer conforms to the structure of the designed product, the structure of the product of Example 1 was determined using Bruker AVANCE400MHz NMR, and the measurement results are as Figure 1 shown. Among them, δ: the -CH3 proton peak on the side chain BA is at 0.96 ppm, δ: the terminal proton peak of the side chain HPEG is at 1.21 ppm, δ: the methylene proton peaks of the side chain BA are at 1.34 and 1.65 ppm, and δ: the methyl proton peak on the main chain HPEG is at 2.24 ppm. Among them, δ: the methylene proton peak of the EO unit on the side chain HPEG is at 3.64 ppm, and δ: the methylene proton peaks of the HPEG main chain are at 4.92 and 4.97 ppm, indicating the successful preparation of the product.

[0062] 2. Static light scattering

[0063] The weight-average molecular weight of the butyl acrylate and methallyl polyoxyethylene ether polymer prepared in the above-mentioned examples was measured by static light scattering. Using water as the solvent, the instrument model is: DAWN HELEOS. The measured weight-average molecular weight is 1.494×10 5 -5.259×10 5 , the weight-average molecular weight of the HPEG monomer is 8000, and n = 172 in the polymer. The specific values of x and y are shown in Table 1 below.

[0064] Table 1

[0065] Sample x y Mw Example 1 <![CDATA[1.18×10 3 > 40 <![CDATA[5.259×10 5 > Example 2 <![CDATA[1.23×10 3 > 20 <![CDATA[3.158×10 5 > Example 3 <![CDATA[0.7×10 3 > 8 <![CDATA[1.494×10 5 > Example 4 <![CDATA[1.218×10 3 > 12 <![CDATA[2.599×10 5 > Example 5 <![CDATA[1.411×10 3 > 15 <![CDATA[3.012×10 5 > Example 6 <![CDATA[1.347×10 3 > 14 <![CDATA[2.874×10 5 > Example 7 <![CDATA[1.259×10 3 > 13 <![CDATA[2.687×10 5 > Example 8 <![CDATA[1.014×10 3 > 11 <![CDATA[2.164×10 5 >

[0066] 3. Demulsification effect

[0067] According to "SY / T 5281-2000 Detection Method for the Use Performance of Crude Oil Demulsifiers (Bottle Test Method)". The demulsification effect was characterized, and the oil sample was super heavy oil with a viscosity of 9x10 5 mPa·s at room temperature. It was found that under the conditions of 80 °C, 3 h, and a dosage of 500 ppm, the demulsification effect of Example 3 could reach 96%. As Figure 2 shown. PEA represents the polymer type, and the following numbers represent the feeding mass ratio.

[0068] 4. Surface tension

[0069] The surface tension of the copolymer was measured using a KRUSS-K100 surface tensiometer made in Germany, and its CMC value was speculated. From Figure 3 It can be seen that as the feed amount of butyl acrylate increases, the ability to reduce the surface tension first increases and then decreases. When the feed ratio is 5:5, the surface tension can be lowered to a minimum of 40 mN / m, showing a good effect of reducing the surface tension. When the feed ratio reaches 4:6, the ability to reduce the surface tension decreases. This is because the increase in hydrophobic groups reduces the number of molecules aggregated at the water surface and makes it easier to form micelles in the aqueous phase, resulting in a weakened ability to reduce the surface tension.

[0070] The CMC value was speculated based on the information in the figure, and the CMC values of the samples were all between 300 mg / L and 400 mg / L.

Claims

1. A side-chain polyether amphiphilic polymer demulsifier for super heavy oil, characterized in that, The demulsifier has the structure shown in the following formula (I): In formula (I), n is an integer from 171 to 173, x is an integer of (0.6 - 1.5)×10 3 , and y is an integer from 7 to 40.

2. The preparation method of the side-chain polyether type amphiphilic polymer super heavy oil demulsifier according to claim 1, comprising the following steps: Add methyl allyl polyoxyethylene ether to solvent A, heat up to the reaction temperature, and add the initiator solution; then add butyl acrylate for reaction to obtain the side-chain polyether type amphiphilic polymer super heavy oil demulsifier.

3. The preparation method of the side-chain polyether amphiphilic polymer demulsifier for super heavy oil according to claim 2, wherein, The solvent A is acetonitrile; the ratio of the total mass of methyl allyl polyoxyethylene ether and butyl acrylate to the volume of solvent A is 1 g: 2 - 5 mL.

4. The preparation method of the side-chain polyether amphiphilic polymer demulsifier for super heavy oil according to claim 2, wherein, The reaction temperature is 65 - 80 °C.

5. The preparation method of the side-chain polyether type amphiphilic polymer demulsifier for super heavy oil according to claim 2, characterized in that, The reaction temperature is 70 - 75 °C.

6. The preparation method of the side-chain polyether type amphiphilic polymer demulsifier for super heavy oil according to claim 2, characterized in that The initiator is azobisisobutyronitrile or benzoyl peroxide; the initiator solution is obtained by dissolving the initiator in solvent B, and the solvent B is the same as solvent A; the concentration of the initiator solution is 0.001 - 0.01 g / mL.

7. The preparation method of the side-chain polyether type amphiphilic polymer demulsifier for super heavy oil according to claim 2, characterized in that The mass ratio of methyl allyl polyoxyethylene ether to butyl acrylate is 6:4 - 2:

8.

8. The preparation method of the side-chain polyether type amphiphilic polymer demulsifier for super heavy oil according to claim 2, characterized in that, The mass ratio of methyl allyl polyoxyethylene ether to butyl acrylate is 6:4, 5:5, 4:6 or 2:

8.

9. The preparation method of the side-chain polyether amphiphilic polymer demulsifier for super heavy oil according to claim 2, characterized in that, The butyl acrylate is added dropwise into the system, and the dropping time is 20 - 40 min; The mass of the initiator is 0.2 - 1% of the total mass of methyl allyl polyoxyethylene ether and butyl acrylate.

10. The preparation method of the side-chain polyether type amphiphilic polymer demulsifier for super heavy oil according to claim 2, characterized in that, The reaction is carried out under a nitrogen atmosphere, and the reaction time is 8 - 15 h.

11. The preparation method of the side-chain polyether type amphiphilic polymer demulsifier for super heavy oil according to claim 2, characterized in that, After the reaction is completed, it also includes a post-treatment step, specifically as follows: Remove the solvent from the obtained reaction solution, soak the obtained product with ether, white precipitate appears, pour off the supernatant, and vacuum dry at 40 - 50 °C for 2 - 4 h to obtain a white powder, which is the side-chain polyether type amphiphilic polymer super heavy oil demulsifier.

12. Use of the side-chain polyether amphiphilic polymer demulsifier for super heavy oil described in claim 1 for demulsifying super heavy oil; the viscosity of the super heavy oil at room temperature is 9×10 5 mPa·s - 15×10 5 mPa·s.

Images