A compound oil displacement agent and its preparation method and application

Abstract

The present invention provides a compound oil-displacing agent, a preparation method, and an application thereof. The compound oil-displacing agent comprises, by weight, 0.1-10 parts of a particle electrode, 0.1-10 parts of a surfactant, and 80-99.8 parts of water. The compound oil-displacing agent provided by the present invention has high stability and can effectively improve oil recovery.

Description

Technical Field

[0001] The present invention belongs to the technical field of oilfield development, and specifically relates to a compound oil-displacing agent, a preparation method and an application thereof, and in particular relates to a compound oil-displacing agent with good stability, a preparation method and an application thereof. Background Art

[0002] At present, the recovery rate of primary and secondary oil recovery in oil fields is about 35%, and a large amount of residual oil remains in the reservoir. In order to improve the oil recovery rate, researchers have proposed a three-dimensional electrochemical oil recovery system and method based on particle electrodes (CN202211130746.5). This invention adds particle electrodes to the traditional electric field oil recovery, transforms the oil reservoir into a three-dimensional electrode system, and increases the electrochemical reaction area. However, when using only particle electrodes as oil recovery agents, there are problems such as uneven dispersion and instability, which can easily have an adverse effect on the oil recovery effect.

[0003] Therefore, how to provide an oil displacement agent containing particle electrodes that has high stability and can effectively improve the recovery rate has become an urgent problem to be solved. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention aims to provide a compound oil-displacing agent, a preparation method thereof, and an application thereof, and in particular to provide a compound oil-displacing agent with good stability, a preparation method thereof, and an application thereof. The compound oil-displacing agent provided by the present invention has high stability and can effectively improve oil recovery.

[0005] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a compound oil-displacing agent, characterized in that the compound oil-displacing agent comprises, by weight, 0.1-10 parts of particle electrodes, 0.1-10 parts of surfactants, and 80-99.8 parts of water.

[0007] Among them, the number of particle electrodes can be 0.1 parts, 0.5 parts, 1 parts, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts, etc., the number of surfactants can be 0.1 parts, 0.5 parts, 1 parts, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts, etc., and the number of water parts can be 80 parts, 82 parts, 84 parts, 86 parts, 88 parts, 90 parts, 92 parts, 94 parts, 96 parts, 98 parts or 99.8 parts, etc., but are not limited to the values ​​listed above. Other values ​​not listed within the above numerical range are also applicable.

[0008] The above-mentioned compound oil-displacing agent can effectively and stably disperse the particle electrodes by adopting specific surfactants, thereby solving the problems of uneven dispersion and instability of the particle electrodes when used as oil-displacing agents, and can give full play to the characteristics of three-dimensional electrochemical drive to improve oil recovery rate.

[0009] Preferably, the compound oil-displacing agent comprises, by weight, 3-7 parts of particle electrodes, 3-7 parts of surfactants, and 84-94 parts of water.

[0010] Preferably, the particle electrode is prepared by a method comprising the following steps:

[0011] Esters, alcohols and a first catalyst are mixed and reacted to obtain polyester oligomers, which are then mixed and reacted with a second catalyst and a stabilizer to obtain polyester. The polyester is then mixed with nano-metal oxides and an organic solvent to obtain a suspension, which is then mixed with a surfactant and water to obtain an oil-in-water emulsion. Finally, the oil-in-water emulsion is heated, the organic solvent is evaporated, the emulsion is broken, the suspension is washed, and the suspension is dried to obtain the particle electrode.

[0012] Preferably, the esters include any one of dimethyl terephthalate, dimethyl 5-sulfoisophthalate, or lactide, or a combination of at least two thereof.

[0013] Preferably, the alcohol includes any one of ethylene glycol, polyethylene glycol or tetraethylene glycol, or a combination of at least two of them.

[0014] Preferably, the first catalyst and the second catalyst are independently any one of zinc acetate, antimony glycolate, antimony trioxide or stannous octoate, or a combination of at least two thereof.

[0015] Preferably, the stabilizer includes any one of triphenyl phosphite, triphenyl phosphate, diphenyl phosphite, diphenyl phosphate, trimethyl phosphate or dimethyl phosphate, or a combination of at least two thereof.

[0016] Preferably, the organic solvent comprises chloroform and / or dichloromethane.

[0017] Preferably, the nano metal oxide includes any one of nano aluminum oxide, nano ferroferric oxide, nano ferric oxide, nano copper oxide, nano nickel oxide, and nano zinc oxide, or a combination of at least two thereof.

[0018] Preferably, the mass ratio of the esters to the alcohols is 1:4-3:4.

[0019] Preferably, the ratio of the total mass of the esters and alcohols to the mass of the first catalyst is (100-600):1.

[0020] Preferably, the mass ratio of the second catalyst to the polyester oligomer is 1:200-1:800.

[0021] Preferably, the total mass fraction of the nano metal oxide and polyester in the particle electrode is 10-50%.

[0022] Preferably, the mass ratio of the nano metal oxide to polyester is 1:2-2:1.

[0023] Preferably, the surfactant includes any one or a combination of at least two of sodium dodecylsulfonate, sodium lauryl sulfate, fatty alcohol ether carboxyl betaine, mixed fatty acid amide propyl betaine, hexadecyltrimethylammonium bromide, sodium diphenylamine sulfonate or sodium dodecylbenzenesulfonate.

[0024] Among them, the surfactant can be a combination of sodium dodecyl sulfonate and sodium dodecyl sulfate, a combination of sodium dodecyl sulfonate and hexadecyltrimethylammonium bromide, or a combination of sodium diphenylamine sulfonate and sodium dodecylbenzene sulfonate, etc., but is not limited to the combinations listed above. Other combinations not listed within the above combination range are also applicable.

[0025] Preferably, the fatty alcohol ether carboxy betaine is one or a combination of at least two of the compounds shown in Formula I:

[0026]

[0027] The structure of R' is as follows:

[0028]

[0029] R is a straight chain alkyl group selected from C 10 H 21 、C 11 H 23 、C 12 H 25 、C 13 H 27 、C 14 H 29 、C 16 H 33 、C 18 H 37 、C 20 H 41 、C 22 H 45 or C 24 H 47 Any one of , n is selected from 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9.

[0030] Preferably, the mixed fatty acid amide propyl betaine is one or a combination of at least two of the compounds shown in formula II:

[0031]

[0032] Wherein, R1 is selected from a saturated straight-chain alkyl group or an unsaturated straight-chain alkyl group containing 1-3 double bonds, the saturated straight-chain alkyl group is a C15-C23 alkyl group, and the unsaturated straight-chain alkyl group containing 1-3 double bonds is a C15-C23 alkyl group.

[0033] R2 is selected from methyl, ethyl, propyl or hydroxyethyl.

[0034] X is selected from sodium acetic acid carboxylate, sodium ethanesulfonate, sodium propanesulfonate or sodium hydroxypropanesulfonate.

[0035] Preferably, the surfactant comprises a combination of at least two of sodium lauryl sulfonate, sodium lauryl sulfate, fatty alcohol ether carboxyl betaine, mixed fatty acid amide propyl betaine, hexadecyltrimethylammonium bromide, sodium diphenylamine sulfonate or sodium dodecylbenzene sulfonate.

[0036] Preferably, the surfactant is a combination of fatty alcohol ether carboxy betaine, mixed fatty acid amide propyl betaine and sodium dodecylbenzene sulfonate.

[0037] Compared with other surfactant combinations, the above-mentioned specific surfactant combination can further improve the stability of the product and increase the oil recovery rate.

[0038] In a second aspect, the present invention provides a method for preparing the compound oil-displacing agent as described above, the preparation method comprising the following steps: mixing part of water and a surfactant, then mixing with a particle electrode, and finally mixing with the remaining water to obtain the compound oil-displacing agent.

[0039] In a third aspect, the present invention further provides the use of the compound oil-displacing agent described above in the preparation of a petroleum oil-displacing agent.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The present invention provides a compound oil-displacing agent. By adopting a specific surfactant, it can effectively and stably disperse particle electrodes, solve the problems of uneven dispersion and instability when particle electrodes are used as oil-displacing agents, and give full play to the characteristics of three-dimensional electrochemical drive to improve oil recovery rate. Moreover, by selecting a specific surfactant combination, the stability of the product can be further improved compared with other surfactant combinations, thereby improving oil recovery rate. DETAILED DESCRIPTION

[0042] In order to further illustrate the technical means and effects adopted by the present invention, the technical solutions of the present invention are further described below in conjunction with the preferred embodiments of the present invention, but the present invention is not limited to the scope of the embodiments.

[0043] Preparation Example 1

[0044] This preparation example provides a fatty alcohol ether carboxy betaine (N-[hexadecyl polyoxyethylene ether (3)-2-hydroxypropyl]-N,N-dimethyl carboxy betaine). For the specific preparation process, see Preparation Example 1 of CN102775976A.

[0045] Preparation Example 2

[0046] This preparation example provides a mixed fatty acid amidopropyl betaine (rapeseed oil fatty acid amidopropyl carboxyethyl betaine). For the specific preparation process, please refer to the specific implementation method section of CN103525390A.

[0047] The fatty alcohol ether carboxyl betaine and mixed fatty acid amide propyl betaine in the following examples are both from Preparation Example 1-2.

[0048] Example 1

[0049] This embodiment provides a composite oil-displacing agent, the specific components of which are as follows (in parts by weight):

[0050] 5 parts of particle electrode (preparation reference CN202211130746.5 Example 1), 1 part of fatty alcohol ether carboxyl betaine, 2 parts of mixed fatty acid amide propyl betaine, 2 parts of sodium dodecylbenzenesulfonate, and 90 parts of water.

[0051] The preparation method is as follows:

[0052] Fatty alcohol ether carboxyl betaine, mixed fatty acid amide propyl betaine, sodium dodecylbenzene sulfonate and part of water are mixed, then mixed with particle electrodes, and finally mixed with the remaining water to obtain the composite oil-displacing agent.

[0053] Example 2

[0054] This embodiment provides a composite oil-displacing agent, the specific components of which are as follows (in parts by weight):

[0055] 3 parts of particle electrode (preparation reference CN202211130746.5 Example 2), 1 part of fatty alcohol ether carboxyl betaine, 1 part of mixed fatty acid amide propyl betaine, 1 part of sodium dodecylbenzene sulfonate, and 84 parts of water.

[0056] The preparation method is as in Example 1.

[0057] Example 3

[0058] This embodiment provides a composite oil-displacing agent, the specific components of which are as follows (in parts by weight):

[0059] 7 parts of particle electrode (preparation reference CN202211130746.5 Example 3), 2 parts of fatty alcohol ether carboxyl betaine, 2 parts of mixed fatty acid amide propyl betaine, 3 parts of sodium dodecylbenzene sulfonate, and 94 parts of water.

[0060] The preparation method is as in Example 1.

[0061] Example 4

[0062] This embodiment provides a composite oil-displacing agent, the specific components of which are as follows (in parts by weight):

[0063] 0.1 parts of particle electrode (preparation reference CN202211130746.5 Example 1), 0.03 parts of fatty alcohol ether carboxyl betaine, 0.03 parts of mixed fatty acid amide propyl betaine, 0.04 parts of sodium dodecylbenzene sulfonate, and 99.8 parts of water.

[0064] The preparation method is as in Example 1.

[0065] Example 5

[0066] This embodiment provides a composite oil-displacing agent, the specific components of which are as follows (in parts by weight):

[0067] 10 parts of particle electrode (preparation reference CN202211130746.5 Example 1), 3 parts of fatty alcohol ether carboxyl betaine, 3 parts of mixed fatty acid amide propyl betaine, 4 parts of sodium dodecylbenzene sulfonate, and 80 parts of water.

[0068] The preparation method is as in Example 1.

[0069] Example 6

[0070] This embodiment provides a compound oil-displacing agent, wherein the specific components are the same as those in Example 1 except that fatty alcohol ether carboxyl betaine is not added and the reduced portion is proportionally distributed to mixed fatty acid amide propyl betaine and sodium dodecylbenzene sulfonate.

[0071] The preparation method is as in Example 1.

[0072] Example 7

[0073] This embodiment provides a compound oil-displacing agent, wherein the specific components are the same as those in Example 1 except that mixed fatty acid amide propyl betaine is not added and the reduced portion is proportionally distributed to fatty alcohol ether carboxy betaine and sodium dodecylbenzene sulfonate.

[0074] The preparation method is as in Example 1.

[0075] Example 8

[0076] This embodiment provides a compound oil-displacing agent. The specific components are the same as those in Example 1, except that sodium dodecylbenzene sulfonate is not added and the reduced portion is proportionally distributed to mixed fatty acid amide propyl betaine and fatty alcohol ether carboxy betaine.

[0077] The preparation method is as in Example 1.

[0078] Example 9

[0079] This embodiment provides a compound oil-displacing agent, wherein the specific components are the same as those in Example 1 except that sodium dodecylbenzenesulfonate is replaced by an equal amount of sodium dodecyl sulfate.

[0080] The preparation method is as in Example 1.

[0081] Example 10

[0082] This example provides a composite oil-displacing agent, wherein the specific components are the same as those of Example 1 except that the mixed fatty acid amidopropyl betaine, fatty alcohol ether carboxy betaine, and sodium dodecylbenzenesulfonate are replaced with an equal amount of hexadecyltrimethylammonium bromide.

[0083] The preparation method is as in Example 1.

[0084] Comparative Example 1

[0085] This comparative example provides an oil-displacing agent, the specific composition (in parts by weight) is as follows:

[0086] 5 parts of particle electrode (prepared according to Example 1 of CN202211130746.5) and 95 parts of water.

[0087] The preparation method is as follows:

[0088] The particle electrode is mixed with water to obtain the oil-displacing agent.

[0089] Stability test:

[0090] The oil-displacing agents provided in Examples 1-10 and Comparative Example 1 were subjected to stability tests. 30 ml of the freshly prepared oil-displacing agent was taken into a test tube and placed vertically and statically. The time when the lower sedimentation stopped increasing was recorded. The results are as follows:

[0091] Group Example 1 Example 2 Example 3 Example 4 Stability (hours) 107 98 96 71 Group Example 5 Example 6 Example 7 Example 8 Stability (hours) 72 48 52 55 Group Example 9 Example 10 Comparative Example 1 Stability (hours) 42 35 28

[0092] From the above results, it can be found that the oil-displacing agent provided by the present invention is more stable than the conventional oil-displacing agent without adding a surfactant; by comparing Examples 1, 6-10, it can be found that the present invention further improves the stability of the product by adopting a combination of surfactants, as well as a specific combination, compared with a single surfactant and other combinations.

[0093] Oil displacement capacity test:

[0094] The oil displacement agents provided in Examples 1-10 and Comparative Example 1 were tested for their oil displacement capacity. A DC voltage of 5 V / cm was applied to both ends of a conventional laboratory core displacement device. The direction of the applied external electric field was the same as the direction of fluid flow. The oil displacement agent was injected for displacement and the fluid output was recorded. The recovery factor was calculated after the test.

[0095] Here are the results:

[0096] Group Example 1 Example 2 Example 3 Example 4 Recovery rate (%) 65 61 60 56 Group Example 5 Example 6 Example 7 Example 8 Recovery rate (%) 58 52 50 51 Group Example 9 Example 10 Comparative Example 1 Recovery rate (%) 49 47 45

[0097] From the above results, it can be found that the oil-displacing agent provided by the present invention has a better oil displacement effect and a higher recovery rate than the conventional oil-displacing agent without adding a surfactant. By comparing Examples 1 and 6-10, it can be found that the present invention further improves the recovery rate of the product by adopting a combination of surfactants and a specific combination compared with a single surfactant and other combinations.

[0098] The applicant declares that the present invention illustrates the composite oil-displacing agent, its preparation method, and application through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments for implementation. Those skilled in the art should understand that any improvements to the present invention, equivalent replacement of the raw materials of the product of the present invention, addition of auxiliary ingredients, selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

[0099] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0100] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A composite oil-displacing agent, characterized in that: The composite oil displacement agent comprises, by weight, 0.1-10 parts of particle electrodes, 0.1-10 parts of a first surfactant, and 80-99.8 parts of water; The first surfactant comprises any one or a combination of at least two of sodium lauryl sulfonate, sodium lauryl sulfate, fatty alcohol ether carboxyl betaine, mixed fatty acid amide propyl betaine, hexadecyltrimethylammonium bromide, sodium diphenylamine sulfonate or sodium dodecylbenzene sulfonate; The particle electrode is prepared by a method comprising the following steps: Esters, alcohols and a first catalyst are mixed and reacted to obtain polyester oligomers, which are then mixed and reacted with a second catalyst and a stabilizer to obtain polyester. The polyester is then mixed with nano-metal oxides and an organic solvent to obtain a suspension, which is then mixed with a second surfactant and water to obtain an oil-in-water emulsion. Finally, the oil-in-water emulsion is heated, the organic solvent is evaporated, the emulsion is broken, the suspension is washed, and the suspension is dried to obtain the particle electrode.

2. The composite oil-displacing agent according to claim 1, wherein The compound oil displacement agent comprises, by weight, 3-7 parts of particle electrodes, 3-7 parts of surfactants, and 84-94 parts of water.

3. The composite oil-displacing agent according to claim 1, wherein The esters include any one of dimethyl terephthalate, dimethyl 5-sulfoisophthalate, or lactide, or a combination of at least two of them.

4. The composite oil-displacing agent according to claim 1, wherein The alcohol includes any one of ethylene glycol, polyethylene glycol or tetraethylene glycol, or a combination of at least two of them.

5. The composite oil-displacing agent according to claim 1, wherein The first catalyst and the second catalyst are independently any one of zinc acetate, antimony glycolate, antimony trioxide or stannous octoate, or a combination of at least two thereof.

6. The composite oil-displacing agent according to claim 1, characterized in that The stabilizer includes any one of triphenyl phosphite, triphenyl phosphate, diphenyl phosphite, diphenyl phosphate, trimethyl phosphate or dimethyl phosphate, or a combination of at least two thereof.

7. The composite oil-displacing agent according to claim 1, characterized in that The organic solvent includes chloroform and / or dichloromethane.

8. The composite oil-displacing agent according to claim 1, characterized in that The nano metal oxide includes any one of nano aluminum oxide, nano ferroferric oxide, nano ferric oxide, nano copper oxide, nano nickel oxide, and nano zinc oxide, or a combination of at least two of the above.

9. The composite oil-displacing agent according to claim 1, characterized in that The mass ratio of the esters to the alcohols is 1:4-3:

4.

10. The composite oil-displacing agent according to claim 1, characterized in that The ratio of the total mass of the esters and alcohols to the mass of the first catalyst is (100-600):

1.

11. The composite oil-displacing agent according to claim 1, characterized in that The mass ratio of the second catalyst to the polyester oligomer is 1:200-1:

800.

12. The composite oil-displacing agent according to claim 1, characterized in that The total mass fraction of the nano metal oxide and polyester in the particle electrode is 10-50%.

13. The composite oil-displacing agent according to claim 1, characterized in that The mass ratio of the nano metal oxide to the polyester is 1:2-2:

1.

14. The composite oil-displacing agent according to claim 1, characterized in that The fatty alcohol ether carboxy betaine is one or a combination of at least two of the compounds shown in Formula I: Formula I; The structure of R' is as follows: R is a straight chain alkyl group selected from C 10 H 21 、C 11 H 23 、C 12 H 25 、C 13 H 27 、C 14 H 29 、C 16 H 33 、C 18 H 37 、C 20 H 41 、C 22 H 45 or C 24 H 47 Any one of , n is selected from 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9.

15. The composite oil-displacing agent according to claim 1, characterized in that: The mixed fatty acid amide propyl betaine is a combination of at least two of the compounds shown in formula Ⅰ: Formula ⅠⅠ; Wherein, R1 is selected from a saturated straight-chain alkyl group or an unsaturated straight-chain alkyl group containing 1-3 double bonds, the saturated straight-chain alkyl group is a C15-C23 alkyl group, and the unsaturated straight-chain alkyl group containing 1-3 double bonds is a C15-C23 alkyl group; R2 is selected from methyl, ethyl, propyl or hydroxyethyl; X is selected from sodium acetic acid carboxylate, sodium ethanesulfonate, sodium propanesulfonate or sodium hydroxypropanesulfonate.

16. The composite oil-displacing agent according to claim 1, characterized in that: The first surfactant includes a combination of at least two of sodium lauryl sulfonate, sodium lauryl sulfate, fatty alcohol ether carboxyl betaine, mixed fatty acid amide propyl betaine, hexadecyltrimethylammonium bromide, sodium diphenylamine sulfonate or sodium dodecylbenzene sulfonate.

17. The composite oil-displacing agent according to claim 16, characterized in that: The first surfactant is a combination of fatty alcohol ether carboxyl betaine, mixed fatty acid amide propyl betaine and sodium dodecylbenzene sulfonate.

18. A method for preparing a composite oil-displacing agent according to any one of claims 1 to 17, characterized in that: The preparation method comprises the following steps: mixing part of water and a surfactant, then mixing with a particle electrode, and finally mixing with the remaining water to obtain the compound oil-displacing agent.

19. Use of the compound oil-displacing agent according to any one of claims 1 to 17 in the preparation of a petroleum oil-displacing agent.

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