CO (carbon monoxide)2Solubilization viscosity reducer and preparation method and application thereof
阅读说明：本技术 一种co2增溶降粘剂及其制备方法和应用 (CO (carbon monoxide)2Solubilization viscosity reducer and preparation method and application thereof ) 是由 冯海顺 王涛 邹斌 林吉生 徐宏光 王善堂 张兆祥 白艳丽 尚跃强 李友平 于 2021-10-22 设计创作，主要内容包括：本发明涉及一种CO-(2)增溶降粘剂,其为具有下式(1)结构的化合物,其中n为0-20的数值；x和y各自独立地选自0-20的数值且x+y≥3。所述CO-(2)增溶降粘剂的分子量为600-4000g/mol。本发明还涉及包含所述化合物的CO-(2)增溶降粘体系,以及其制备方法和用途。(The invention relates to CO 2 A solubilizing viscosity-reducing agent which is a compound having the structure of the following formula (1) wherein n is a number of 0 to 20;x and y are each independently selected from a number from 0 to 20 and x + y ≧ 3. The CO is 2 The molecular weight of the solubilization viscosity reducer is 600-4000 g/mol. The invention also relates to CO comprising said compounds 2 A solubilization and viscosity reduction system, a preparation method and application thereof.)
1. CO (carbon monoxide)2A solubilizing viscosity-reducing agent which is a compound having the structure of the following formula (1):
wherein n is a number from 0 to 20; x and y are each independently selected from a number from 0 to 20 and x + y ≧ 3.
2. CO according to claim 12A solubilizing viscosity-reducing agent, wherein in the structure of formula (1), n is a number from 8 to 12; x and y are each independently selected from a number from 3 to 10 and x + y ≧ 8.
3. C according to claim 1 or 2O2A solubilizing viscosity reducer wherein the CO2The number average molecular weight of the solubilization viscosity reducer is 600-4000g/mol, preferably 800-3000 g/mol.
4. Preparation of CO according to any one of claims 1 to 32A method of solubilizing a viscosity reducer comprising the steps of:
(1) under the alkaline condition and under the heating condition, ethylenediamine and benzyl chloride react to generate N, N' -dibenzyl ethylenediamine;
(2) under heating, the alkylphenol polyoxyethylene polyoxypropylene ether is mixed with SOCl2Reacting to generate chlorinated alkylphenol polyoxyethylene polyoxypropylene ether;
(3) under alkaline conditions, N' -dibenzylethylenediamine and chloroalkylphenol polyoxyethylene polyoxypropylene ether are reacted under the conditions of solvent and heating to obtain CO of a formula (1)2A solubilizing viscosity reducer.
5. The method of claim 4, wherein the alkylphenol polyoxyethylene polyoxypropylene ether has the structure of formula (2):
wherein n is a number from 0 to 20; x and y are each independently selected from a number from 0 to 20 and x + y ≧ 3.
6. The method of claim 4, wherein the chloroalkylphenol polyoxyethylene polyoxypropylene ether has the structure of formula (3):
wherein n is a number from 0 to 20; x and y are each independently selected from a number from 0 to 20 and x + y ≧ 3.
7. The method of claim 4, wherein in step (1), an alkaline environment is formed using NaOH; the molar ratio of the benzyl chloride to the ethylenediamine is 2-2.4: 1.
8. The method according to claim 4, wherein in step (2), the alkylphenol polyoxyethylene polyoxypropylene ether is reacted with SOCl2The molar ratio of (A) to (B) is 1: 1.6-2.
9. The method according to claim 4, wherein in the step (3), a mixture of water and alcohol is used as a solvent, and the reaction is carried out at a pH of 10-12; the molar ratio of the N, N' -dibenzylethylenediamine to the chlorinated alkylphenol polyoxyethylene polyoxypropylene ether is 1: 2.2-2.5.
10. CO (carbon monoxide)2Solubilizing and viscosity-reducing system consisting of CO according to any one of claims 1 to 32Solubilization viscosity reducer and auxiliary agent; wherein the adjuvant is selected from linear or branched C2-C10 alkanol or C3-C10 alkane, or mixtures thereof.
11. CO according to claim 102Solubilization and viscosity reduction system based on CO2100% of the total weight of the solubilization and viscosity reduction system, CO25-50 wt% of solubilization viscosity reducer and 50-95 wt% of auxiliary agent.
12. CO according to claim 10 or 112Solubilizing and viscosity reducing system, wherein the adjuvant is selected from ethanol, propanol, n-hexane, cyclohexane, n-heptane, or mixture thereof.
13. CO according to any of claims 10 to 122The solubilization viscosity reduction system is used for oil displacement and exploitation of low-efficiency heavy oil reservoirs.
14. CO according to any one of claims 1 to 32Solubilization viscosity reducer for preparing CO for oil displacement and exploitation of low-efficiency heavy oil reservoir2Use of a solubilising viscosity-reducing system.
15. According to the claimsThe use of claim 14, wherein the CO is2Solubilizing viscosity reducer and CO2In a mass ratio of 0.8 to 5:1, preferably 1 to 3: 1.
Technical Field
The invention belongs to the technical field of tertiary oil recovery in oilfield development, and particularly relates to CO2Solubilizing viscosity reducers, systems comprising the same, methods of making and uses thereof.
Background
China has rich thick oil resources, and the development mode mainly comprises water drive and steam injection thermal recovery. The average recovery rate of the heavy oil reservoir which is used is about 20 percent, and the heavy oil reservoir has great promotion potential compared with the conventional water flooding (the average recovery rate is 38.4 percent) and chemical flooding (the average recovery rate is 46.5 percent). Part of thick oil blocks are influenced by factors such as buried depth, low permeability, sensitive reservoir and the like, the thick oil thermal recovery benefit is poor, the oil-soluble viscosity reducer is high in use concentration and cost, and the water-soluble viscosity reducer has poor viscosity reduction effect in a low-permeability reservoir. The prior experiments show that for the part of reservoir, CO is singly used2Or the effect of chemical viscosity reduction exploitation is not ideal. Therefore, the use of "CO" in recent years2The oil-soluble viscosity reducer is compounded and huffed, so that a certain effect of reducing cost and increasing oil is achieved.
However, this method still has some problems: one is CO2The dissolution and diffusion speed in the thick oil is slow, the well stewing time is long, and the dissolution amount is small; secondly, the oil-soluble viscosity reducer has large dosage and high cost; III is CO2The interaction relation between the oil-soluble viscosity reducer and the oil-soluble viscosity reducer is less researched, and the two systems respectively play the advantages of the two systems and cannot generate a synergistic effect.
Therefore, there is still a need to develop more efficient CO2The solubilization viscosity reducer can increase CO simultaneously on the basis of certain viscosity reduction effect2Solubility in heavy oil to achieve CO2And the viscosity reduction and the efficiency improvement are cooperated, so that the cost reduction and the efficiency improvement of the viscosity reduction cold recovery technology are realized.
Disclosure of Invention
The invention provides CO2A solubilizing viscosity-reducing agent which is a compound having the structure of the following formula (1):
wherein n is a number from 0 to 20; x and y are each independently selected from a number from 0 to 20 and x + y ≧ 3.
The invention also provides the CO2A method of solubilizing a viscosity reducer comprising the steps of:
(1) under the alkaline condition and under the heating condition, ethylenediamine and benzyl chloride react to generate N, N' -dibenzyl ethylenediamine;
(2) under heating, the alkylphenol polyoxyethylene polyoxypropylene ether is mixed with SOCl2Reacting to generate chlorinated alkylphenol polyoxyethylene polyoxypropylene ether;
(3) under alkaline conditions, N' -dibenzylethylenediamine and chloroalkylphenol polyoxyethylene polyoxypropylene ether are reacted under the conditions of solvent and heating to obtain CO of a formula (1)2A solubilizing viscosity reducer.
The invention further providesCO2Solubilizing viscosity-reducing system consisting of said CO2Solubilization viscosity reducer and auxiliary agent; wherein the adjuvant is selected from linear or branched C2-C10 alkanol or C3-C10 alkane, or mixtures thereof.
The invention further provides said CO2The solubilization viscosity reduction system is used for oil displacement and exploitation of low-efficiency heavy oil reservoirs.
The invention also provides the CO2Solubilization viscosity reducer for preparing CO for oil displacement and exploitation of low-efficiency heavy oil reservoir2Use of a solubilising viscosity-reducing system.
The invention has the beneficial effects that:
(1) CO of the invention2The solubilization viscosity reducer has two long alkylphenol polyoxyethylene polyoxypropylene ether chains and two short benzyl functional group chains, and has stronger lipophilicity and CO affinity2Sex, can convert more CO2Dissolved in crude oil, can greatly increase CO compared with the currently common oil-soluble viscosity reducer2Solubility in thick oil, solubilization viscosity reducer and CO2The viscosity reduction and the efficiency increase are cooperated.
(2) CO of the invention2The solubilization viscosity reduction system can reduce the cost under the condition of not reducing the effect. CO of the invention2The solubilization and viscosity reduction system shows higher crude oil recovery rate in a core physical simulation huff and puff experiment; it is injected into the formation by means of slug, and can simultaneously enhance CO2The solvent is dissolved in crude oil, the viscosity of the crude oil is reduced, and the fluidity of the crude oil is enhanced, so that the aim of improving the recovery efficiency is fulfilled, and the solvent has important significance for the efficient development of an inefficient heavy oil reservoir.
Drawings
FIG. 1 shows the CO after adding different chemical agents in example 1 of the present invention2Dissolved gas to oil ratio of (1).
FIG. 2 shows the CO after adding different chemical agents in example 1 of the present invention2Curve of the fold increase in solubility of (a).
Fig. 3 is a schematic diagram of an experimental setup used in the composite throughput physical simulation experiment of example 3.
Detailed Description
The "ranges" disclosed herein are defined in terms of lower limits and upper limits, with a given range being defined by a selection of one lower limit and one upper limit that define the boundaries of the particular range. Ranges defined in this manner may or may not include endpoints and may be arbitrarily combined, i.e., any lower limit may be combined with any upper limit to form a range. For example, if ranges of 10-50 and 20-40 are listed for a particular parameter, it is understood that ranges of 10-40 and 20-50 are also contemplated. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise stated, the range of values "a-b" represents a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "0 to 5" indicates that all real numbers between "0 to 5" have been listed herein, and "0 to 5" is only a shorthand representation of the combination of these numbers. In addition, when a parameter is an integer of 2 or more, it is equivalent to disclose that the parameter is, for example, an integer of 2,3, 4, 5, 6, 7, 8, 9, 10, or the like.
All embodiments and alternative embodiments of the present application may be combined with each other to form new solutions, if not specifically stated.
All technical and optional features of the present application may be combined with each other to form new solutions, if not otherwise specified.
All steps of the present application may be performed sequentially or randomly, preferably sequentially, if not specifically stated. For example, the method comprises steps (a) and (b), meaning that the method may comprise steps (a) and (b) performed sequentially, and may also comprise steps (b) and (a) performed sequentially. For example, reference to the process further comprising step (c) means that step (c) may be added to the process in any order, for example, the process may comprise steps (a), (b) and (c), may also comprise steps (a), (c) and (b), may also comprise steps (c), (a) and (b), etc.
The terms "comprises" and "comprising" as used herein mean either open or closed unless otherwise specified. For example, the terms "comprising" and "comprises" may mean that other components not listed may also be included or included, or that only listed components may be included or included.
Unless otherwise specified, the reaction is carried out under normal temperature and pressure conditions.
All parts or percentages are by weight, unless otherwise specified.
In the present invention, the substances used are all known substances, and are commercially available or synthesized by known methods.
In the present invention, the apparatus or equipment used is conventional apparatus or equipment known in the art, and is commercially available.
Definition of
The term "linear or branched C3-C10 alkyl" as used herein refers to a branched or linear saturated hydrocarbon chain having 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms. Examples of C3-C10 alkyl include, but are not limited to, propyl (n-propyl), 1-methylethyl (isopropyl), butyl (n-butyl), 1-methylpropyl (sec-butyl), 2-methylpropyl (isobutyl), 1-dimethylethyl (tert-butyl), pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2-dimethylpropyl, 1-ethylpropyl, 1-dimethylpropyl, 1, 2-dimethylpropyl, hexyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1-dimethylbutyl, 1, 2-dimethylbutyl, 1, 3-dimethylbutyl, 2-dimethylbutyl, 2, 3-dimethylbutyl, 3, 3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1, 2-trimethylpropyl, 1,2, 2-trimethylpropyl, 1-ethyl-1-methylpropyl and 1-ethyl-2-methylpropyl, heptyl, 1-methylhexyl, 2-methylhexyl, 3-methylhexyl, 4-methylhexyl, 1-dimethylpentyl, 1, 2-dimethylpentyl, 1, 3-dimethylpentyl group, octyl group, 1-methylheptyl group, 2-methylheptyl group, 3-methylheptyl group, 4-methylheptyl group, nonyl group, 2, 3-dimethylheptyl group, 3-dimethylheptyl group, 1-ethylheptyl group, 2-ethylheptyl group, decyl group.
The term "straight or branched C2-C10 alkanol" as used herein refers to a branched or straight saturated hydrocarbon chain having 2,3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms containing one hydroxyl group, as specifically defined above.
The invention provides CO2A solubilizing viscosity-reducing agent which is a compound having the structure of the following formula (1):
wherein n is a number from 0 to 20; x and y are each independently selected from a number from 0 to 20 and x + y ≧ 3.
In one embodiment of the present invention, in the structure of formula (1), n is a number from 8 to 12; x and y are each independently selected from a number from 3 to 10 and x + y ≧ 8.
In one embodiment of the invention, the CO is2The molecular weight of the solubilization viscosity reducer is 600-4000g/mol, preferably 800-3000 g/mol. CO 22The molecular weight of the solubilizing viscosity reducer is calculated by the number average molecular weight, and the measurement is carried out by a Gel Permeation Chromatography (GPC) method.
The invention also provides the CO2A method of solubilizing a viscosity reducer comprising the steps of:
(1) under the alkaline condition and under the heating condition, ethylenediamine and benzyl chloride react to generate N, N' -dibenzyl ethylenediamine;
(2) under heating, the alkylphenol polyoxyethylene polyoxypropylene ether is mixed with SOCl2Reacting to generate chlorinated alkylphenol polyoxyethylene polyoxypropylene ether;
(3) under alkaline conditions, N' -dibenzylethylenediamine and chloroalkylphenol polyoxyethylene polyoxypropylene ether are reacted under the conditions of solvent and heating to obtain CO of a formula (1)2A solubilizing viscosity reducer.
In one embodiment of the present invention, the alkylphenol polyoxyethylene polyoxypropylene ether has the structure of formula (2):
wherein n is a number from 0 to 20; x and y are each independently selected from a number from 0 to 20 and x + y ≧ 3.
In one embodiment of the present invention, the chloroalkylphenol polyoxyethylene polyoxypropylene ether has the structure of formula (3):
wherein n is a number from 0 to 20; x and y are each independently selected from a number from 0 to 20 and x + y ≧ 3.
In one embodiment of the present invention, wherein in step (1), an alkaline environment is formed with NaOH; the molar ratio of the benzyl chloride to the ethylenediamine is 2-2.4: 1.
In one embodiment of the present invention, wherein in step (2), an aromatic hydrocarbon is used as a solvent; the alkylphenol polyoxyethylene polyoxypropylene ether and SOCl2The molar ratio of (A) to (B) is 1: 1.6-2.
In one embodiment of the present invention, wherein in step (3), a mixture of water and alcohol is used as a solvent, and the reaction is carried out at a pH of 10 to 12; the molar ratio of the N, N' -dibenzylethylenediamine to the chlorinated alkylphenol polyoxyethylene polyoxypropylene ether is 1: 2.2-2.5.
In a particular embodiment of the invention, the CO is2The solubilizing viscosity reducer was prepared as follows:
(1) synthesizing N, N' -dibenzyl ethylenediamine by substitution reaction of ethylenediamine and benzyl chloride; wherein the molar ratio of the benzyl chloride to the ethylenediamine is 2-2.4:1, and the molar ratio of the benzyl chloride to the sodium hydroxide is 1: 1-1.2. Preparing 50% sodium hydroxide aqueous alkali, adding ethylenediamine and benzyl chloride, heating, reacting for 1-4 hours, and cooling. And transferring the mixture into a separating funnel, standing for layering, and washing an oil layer to be neutral by using water to obtain the N, N' -dibenzylethylenediamine.
(2) And carrying out halogenation reaction on alkylphenol polyoxyethylene polyoxypropylene ether to obtain the product of chlorinated alkylphenol polyoxyethylene polyoxypropylene ether. Adding a certain amount of alkylphenol polyoxyethylene polyoxypropylene ether into a three-neck flask, adding a certain amount of benzene as a solvent (or without the solvent),then slowly dropwise adding 1.6-2 times of molar quantity of SOCl into the three-neck flask under stirring2And reacting for 10-16h at the temperature of 70-80 ℃. The reaction was stopped and the reaction was cooled. Neutralizing with 15% NaOH solution to alkalinity, transferring into a separating funnel to separate inorganic salt, and reserving upper organic layer to obtain the product of chloroalkylphenol polyoxyethylene polyoxypropylene ether.
(3) Adding the reaction product N, N '-dibenzyl ethylenediamine in the step (1) into a three-neck flask according to the proportion of N, N' -dibenzyl ethylenediamine and K2CO3The molar ratio is 1:1-1.2, K is added2CO3Dissolving to provide an alkaline environment. Dissolving chloroalkylphenol polyoxyethylene polyoxypropylene ether in a mixed solution (1:1) of ethanol and water, slowly dropwise adding the solution into a three-neck flask, and reacting at 70-90 ℃ for 8-12 h. Stopping reaction, cooling, distilling under reduced pressure, adding an organic solvent, dissolving, filtering, distilling under reduced pressure and purifying to obtain a reaction product.
The reaction equation is as follows:
the first step is as follows:
the second step is that:
the third step:
the invention also provides CO2Solubilizing viscosity-reducing system consisting of said CO2Solubilization viscosity reducer and auxiliary agent; wherein the adjuvant is selected from linear or branched C2-C10 alkanol or C3-C10 alkane, or mixtures thereof. The CO is2The solubilizing viscosity reducer is taken as a main agent and is compounded with an organic solvent auxiliary agent according to a certain proportion to form CO2Solubilization system for reducing viscosityThe solubility of the solubilization viscosity reducer in crude oil can be improved by over-compounding, and the cost is reduced under the condition of not reducing the using effect.
In one embodiment of the invention, based on CO2100% of the total weight of the solubilization and viscosity reduction system, CO25-50 wt% of solubilization viscosity reducer and 50-95 wt% of auxiliary agent; preferably CO215-45 wt% of solubilization viscosity reducer and 55-85 wt% of auxiliary agent; more preferably CO220-40 wt% of solubilization viscosity reducer and 60-80 wt% of auxiliary agent; further preferred is CO222-30 wt% of solubilization viscosity reducer and 70-78 wt% of auxiliary agent.
In one embodiment of the invention, the adjuvant is selected from ethanol, propanol, n-hexane, cyclohexane, n-heptane, or mixtures thereof.
The invention also provides the CO2The solubilization viscosity reduction system is used for oil displacement and exploitation of low-efficiency heavy oil reservoirs.
The invention further provides said CO2Solubilization viscosity reducer for preparing CO for oil displacement and exploitation of low-efficiency heavy oil reservoir2Use of a solubilising viscosity-reducing system.
CO of the invention2The solubilizing viscosity reducer is generally used in an amount of from 2 to 10% by weight, preferably from 3 to 6% by weight, based on the mass of the crude oil to be recovered.
In one embodiment of the invention, the CO is2Solubilizing viscosity reducer and CO2In a mass ratio of 0.8 to 5:1, preferably 1 to 3: 1.
CO of the invention2The solubilization viscosity reduction system comprises a compound with a specific structure as the CO shown in the formula (1)2Solubilizing viscosity reducers, which are injected into the formation by means of slugging, can simultaneously enhance CO2The dissolution in the crude oil and the reduction of the viscosity of the crude oil enhance the fluidity of the crude oil, thereby realizing the purpose of improving the recovery efficiency.
The present invention will be described in further detail with reference to examples.
Preparation examples
Example 1: preparation of CO according to the invention2Solubilization viscosity reducer GBE3P6
(1) Synthesis of N, N' -dibenzyl ethylenediamine
Adding 0.22mol of sodium hydroxide and 8.8g of water into a three-neck flask which is provided with a stirrer, a thermometer and a reflux condenser to prepare a 50% alkali solution, then sequentially adding 0.1mol of ethylenediamine and 0.22mol of benzyl chloride into the three-neck flask, reacting for 4 hours at 55 ℃, cooling, transferring the mixture into a separating funnel, standing and layering, and washing an oil layer to be neutral by using water to obtain N, N' -dibenzylethylenediamine;
(2) synthesis of chlorononyl phenol polyoxyethylene (3EO) polyoxypropylene (6PO) ether
Adding 0.22mol of nonylphenol polyoxyethylene (3EO) polyoxypropylene ether (6PO) ether into a three-neck flask, adding 0.22mol of benzene as a solvent, heating to the reaction temperature of 70 ℃ under stirring, and slowly dropwise adding 0.396mol of SOCl into the three-neck flask by using a constant-pressure dropping funnel2Controlling the titration speed to prevent a large amount of white smoke from volatilizing, reacting for 8 hours, stopping the reaction, and cooling the reactant. Neutralizing with 10% sodium hydroxide solution to alkaline, keeping the upper organic layer, washing with 80 deg.C hot water for 2-3 times to obtain chlorinated nonylphenol polyoxyethylene (3EO) polyoxypropylene (6PO) ether;
(3)CO2solubilization viscosity reducer GBE3P6Synthesis of (2)
0.1mol of N, N' -dibenzylethylenediamine is weighed and added into a three-neck flask, the mixture is heated to the reaction temperature of 70 ℃ under stirring, and 0.22mol of K is added2CO3And 0.22mol of chlorinated nonylphenol polyoxyethylene (3EO) polyoxypropylene (6PO) ether were dissolved in 100mL of a mixture of ethanol and water (volume ratio: 1) in this order, the solution was slowly dropped into a three-necked flask using a constant pressure dropping funnel, and a sodium hydroxide solution was added dropwise to adjust the pH to about 10, followed by reflux reaction at 75 ℃ for 10 hours. The reaction was stopped and the reaction was cooled. Distilling under reduced pressure, adding ethanol for dissolving, filtering, continuing distilling under reduced pressure, and repeating for 2-3 times to obtain a product;
application examples
Example 2
CO to the invention2Solubilization viscosity reducer GBE3P6And oil soluble viscosity reducer YR-1 (mixture of C8-C16 hydrocarbon compounds comprising petroleum straight-run fraction, hydrocracking and hydrofining as main component) for reducing viscosity and increasing CO2And (4) evaluating the solubility performance. The oil sample is degassed and dehydrated crude oil of a certain oil field, and the viscosity of the oil sample is 3340mPa.s after dehydration at 50 ℃.
Inventive and comparative samples were prepared as follows:
respectively taking 47.5g of oil samples in beakers, and keeping the temperature of water bath for 2 hours; adding GBE separately3P6And YR-12.5g, keeping the temperature for 30min, and fully stirring to obtain the invention sample and the comparison sample.
1. Evaluation of viscosity-reducing Effect
Separate addition of GBE using BROOKFIELD DV-III viscometer test3P6And before and after YR-1, the results are shown in Table 1.
TABLE 1 evaluation of viscosity reduction Effect
As can be seen from Table 1, the viscosity reduction rate of the viscosity reducer of the invention on crude oil reaches 79.9%, and the viscosity reducer has better effect than a comparative oil-soluble viscosity reducer.
2.CO2Evaluation of solubility Properties
Weighing 200g of oil sample, placing into a main cylinder of a PVT analyzer (from Haian Petroleum technology), and charging excessive CO under pressure2Setting the temperature at 60 ℃ and the pressure at 6 MPa; setting a stirring program, waiting for 10min, stirring for more than 6h, mixing well, stabilizing for 1h, and measuring CO2The solubility of (a). The pressure was changed to 6MPa, 7.38MPa, 10MPa, 15MPa, and 25MPa in this order for measurement. The crude oil, inventive sample and comparative sample were subjected to experiments, respectively, and the results were compared, and the experimental results are shown in fig. 1 to 2.
As can be seen from FIG. 1, the dissolved gas-oil ratio of the inventive sample and the comparative sample is improved to a certain extent under different pressures, and the improvement effect of the inventive sample is obviously higher than that of the comparative sample. As can be seen from FIG. 2, the inventive samples can raise CO at different pressures2The dissolution amount in crude oil is more than 30%.
Example 3
Inventive CO2Solubilization and viscosity reduction system: the system is composed of GBE3P6And ethanol, GBE3P6And ethanol in a mass ratio of 1: 3.
comparative CO2Solubilization and viscosity reduction system: an oil soluble viscosity reducer YR-1 system.
For the above two systems + CO2And carrying out a composite throughput physical simulation experiment. The physical simulation experimental device was purchased from Haian Petroleum science and technology, as shown in FIG. 3. The evaluation method is carried out according to the evaluation of the oil displacement performance of the complex oil displacement system in the performance test method of the SY-T6424-2014 complex oil displacement system. The permeability of the core 1 is 1.629mD, the initial oil saturation is 83.2%, the water flooding recovery rate is 40.9%, the permeability of the core 2 is 1.516mD, the initial oil saturation is 82.2%, the water flooding recovery rate is 41.2%, and the permeability of the core 2 is respectively corresponding to' CO2+ YR-1 viscosity reducer system "and" CO2+GBE3P6Solubilization viscosity reduction system "experiments were performed.
According to the experimental design, the injection amount is 5g system +12.5g CO2", three runs were performed per set of experiments. The method comprises the steps of loading 100g of crude oil into an intermediate container arranged on a simulation experiment device, simulating pressure and material compensation of a stratum deep part on a core barrel, injecting according to design amount, controlling the intermediate container to slowly reduce outlet pressure to 7MPa to simulate a soaking process, wherein the soaking time is more than 12h, starting up a well for production until no production is produced, sequentially carrying out three designed round experiments, separating produced liquid through a gas-water separation device, then respectively measuring, and recording and analyzing experiment data. The results are shown in Table 2.
As can be seen from Table 2, the production levels were all measured by injecting the inventive system and the comparative system separatelyThe improvement is obtained, but the extraction degree is obviously reduced along with the increase of the injection throughput. "CO2The liquid production, water content and extraction degree of the invention system are all better than that of the CO2+ comparison system ", the total enhanced production degree of three rounds is 16.09% and 12.56% respectively, which shows that the effect is obviously enhanced after the solubilization viscosity-reduction system of the invention is used.
TABLE 2 "CO2+ system composite throughput experiment effect table
As can be seen from the above application examples, the CO of the present invention2Solubilization viscosity reducer can increase CO2Solubility in thick oil, solubilization viscosity reducer and CO2The viscosity reduction and the efficiency increase are cooperated; CO of the invention2The solubilization viscosity reduction system can achieve the purpose of improving the recovery efficiency and has important significance for the efficient development of the low-efficiency heavy oil reservoir.