Oil displacement composition and preparation method and application thereof

Abstract

The present invention relates to the field of oil displacement, and discloses an oil displacement composition, a preparation method thereof and an application thereof. The oil displacement composition comprises a surfactant, a polymer and an amino organic compound; the surfactant is selected from at least one of anionic surfactants, cationic surfactants and nonionic surfactants. The oil displacement composition has high solubilization and permeability performance, and is particularly suitable for heterogeneous oil fields with high clay content and heterogeneous oil fields with high water content and high recovery degree. Under complex reservoir conditions with certain slugs, it still has a high final recovery rate, improves the recovery rate of the complex working conditions, and has better adaptability.

Description

Technical Field

[0001] The present invention relates to an oil displacement composition, and more particularly to an oil displacement composition and a preparation method and application thereof. Background Art

[0002] Polymer flooding is the main means of chemical flooding to enhance oil recovery in my country. Most of the blocks suitable for polymer flooding have implemented polymer flooding, and some blocks have entered the subsequent water flooding stage, with water content rising rapidly. After polymer flooding, the oil layer has high water content, high recovery degree, more serious heterogeneity between layers and within layers, and a large amount of scattered residual oil exists, which gradually changes from network bands to porous, isolated, oil film attached to the pore wall, blind end in dead corners, and rods in throats. Therefore, it is more difficult to start the residual oil in the reservoir after polymer flooding, and it is difficult to displace the above residual oil with conventional water flooding, resulting in low water flooding efficiency and greater difficulty in tapping potential in the later stage of water flooding development of such oil reservoirs. Major oil fields generally face difficulties and huge pressures such as high water content, high mining cost, and low recovery rate. The subsequent replacement technology is unclear, and new technologies with higher oil displacement efficiency and stronger residual oil startup ability are needed to enhance recovery rate. Therefore, the key to further significantly improve the recovery rate is to further improve the oil washing efficiency of the high permeability layer, while improving the injection performance of the medium and low permeability layers and increasing the swept volume.

[0003] Compared with the composite flooding technology (binary and ternary composite flooding technology) and foam composite flooding technology that are currently under research, microemulsion flooding technology has higher oil recovery efficiency and stronger residual oil startup ability. The application of yin and yang composite surfactants greatly improves the oil recovery efficiency.

[0004] Therefore, in order to cope with more complex reservoir conditions, the present invention provides an oil displacement composition, which further improves the solubilization and seepage performance while retaining the high interfacial performance of the surfactant. It is particularly suitable for heterogeneous oil fields with high clay content and heterogeneous oil fields with high water content and high recovery degree, and has better adaptability to the demand for significantly improving the recovery rate. Summary of the invention

[0005] In order to overcome the problems existing in the prior art, the present invention provides an oil displacement composition and a preparation method and application thereof. The oil displacement composition has high solubilization and seepage performance, and is particularly suitable for heterogeneous oil fields with high clay content and heterogeneous oil fields with high water content and high recovery degree. Under complex reservoir conditions with certain slugs, it still has a high final recovery rate, improves the enhanced recovery rate of the complex working conditions, and has better adaptability.

[0006] One of the purposes of the present invention is to provide an oil displacement composition, comprising a surfactant, a polymer and an amino organic compound; the surfactant is selected from at least one of anionic surfactants, cationic surfactants and nonionic surfactants.

[0007] According to the present invention, the surfactant can be selected from anionic surfactants, cationic surfactants, and nonionic surfactants. In a preferred embodiment of the present invention, the surfactant is selected from at least one of anionic surfactants, cationic surfactants, and nonionic surfactants; more preferably, the surfactant contains anionic surfactants and cationic surfactants; further more preferably, the anionic surfactant is an anionic-nonionic surfactant, and the surfactant contains anionic-nonionic surfactants and cationic surfactants; further more preferably, the molar ratio of the cationic surfactant to the anionic-nonionic surfactant is 1:(0.01-100), preferably 1:(0.1-10).

[0008] According to the present invention, preferably, the molar ratio of the cationic surfactant to the anionic-nonionic surfactant is 1:(0.01-100), preferably 1:(0.1-10), for example, it can be 1:0.1, 1:0.4, 1:0.8, 1:1.2, 1:1.5, 1:2, 1:4, 1:6, 1:8, 1:10, and the ratio of 1 to any value between 0.1 and 10 or any interval between any two values.

[0009] For the above yin-yang compound surfactants, the selection range of cationic surfactants is relatively wide, for example, cationic surfactants containing more than 4 C-containing groups. In a preferred embodiment of the present invention, the cationic surfactant is selected from quaternary ammonium salts and / or quaternary amine bases; preferably, the cationic surfactant is selected from quaternary ammonium salts with C4-C22 alkyl groups and / or quaternary amine bases with C4-C22 alkyl groups. More preferably, the quaternary ammonium salt is selected from at least one of tetraalkylammonium chloride, tetraalkylammonium bromide, tetraalkylammonium hydrogen sulfate and alkylbenzylammonium chloride; the quaternary amine base is selected from tetraalkylammonium hydroxide and / or alkylbenzylammonium hydroxide; further more preferably, the cationic surfactant is selected from tetraalkylammonium chloride and / or tetraalkylammonium hydroxide. For example, at least one selected from hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, hexadecylbenzyldimethylammonium chloride, tetradecyltrimethylammonium chloride, dodecyltrimethylammonium chloride, tetrabutylammonium chloride, dioctadecyldimethylammonium chloride, dedecyltriethylammonium chloride, tetraoctylammonium chloride, and benzyltriethylammonium chloride, and more preferably at least one selected from dodecyltrimethylammonium chloride, tetrabutylammonium chloride, dioctadecyldimethylammonium chloride, dedecyltriethylammonium chloride, tetraoctylammonium chloride, and benzyltriethylammonium chloride.

[0010] For the above anionic surfactants, the anionic surfactant has a wide selection range. In a preferred embodiment of the present invention, the anionic surfactant is an anionic-nonionic surfactant; more preferably, the anionic-nonionic surfactant is selected from alkyl polyether carboxylates and / or polyether sulfonates; and more preferably, selected from polyoxyethylene polyoxypropylene ether sulfonates and / or polyoxyethylene polyoxypropylene ether carboxylates. More preferably, it is selected from compounds represented by formula (I) and / or formula (II).

[0011]

[0012] Wherein, in formula (I) and formula (II), M is selected from any one of alkali metal, alkaline earth metal or ammonium ion, and R is selected from H, C1-C 20 Any one of an alkyl group, a phenyl group, or a substituted phenyl group, and n is any integer from 0 to 100.

[0013] In a further preferred embodiment, in formula (I) and formula (II), M is independently selected from Na, K, Mg, Ca or NH4 + Any one of; R is each selected from H, C5-C 15 Alkyl, C5-C 15 Any one of the phenyl groups substituted by an alkyl group; n is any integer from 0 to 100.

[0014] In a further preferred embodiment, the anionic-nonionic surfactant is selected from at least one of octylphenol polyoxyethylene ether carboxylate, alkylphenol polyoxyethylene ether carboxylate, and isomeric tridecyl alcohol polyoxyethylene ether carboxylate.

[0015] According to the present invention, the anionic-nonionic surfactant can be commercially available or prepared by existing technology. For example, it can be prepared by the technical solutions disclosed in CN101279935 A, CN111088011 A, CN111088013 A, and CN111088014A.

[0016] According to the present invention, the polymer can be selected from conventional polymers used for oil displacement in the art. In a preferred embodiment of the present invention, the polymer is selected from water-soluble polymers, preferably selected from at least one of water-soluble polyacrylamide, acrylate, xanthan gum, cellulose ether compounds, and polyvinyl pyrrolidone.

[0017] According to the present invention, the amino organic compound can have a variety of choices. In a preferred embodiment of the present invention, the amino organic compound is selected from at least one of C8-C12 fatty amines, C2-C12 fatty diamines, C5-C8 alicyclic amines, N-heterocyclic aromatic hydrocarbons, and aminophenols. For example, it can be selected from commercially available products including but not limited to diethylamine, triethylamine, isopropylamine, 1,3-propylenediamine, 1,2-propylenediamine, tripropylamine, butylamine, isobutylamine, tert-butylamine, benzylamine, cyclohexylamine, pyridine, o-aminophenol, m-aminophenol, p-aminophenol, etc. More preferably, the amino organic compound is selected from at least one of benzylamine, cyclohexylamine, octylamine, 1,3-propylenediamine, 1,2-propylenediamine, pyridine, m-aminophenol, o-aminophenol, and p-aminophenol.

[0018] According to the present invention, the mass ratio of the surfactant, polymer and amino organic compound has a wide selection range. In a preferred embodiment of the present invention, the mass ratio of the surfactant, polymer and amino organic compound is 1:(0.1-1):(0.01-100), preferably 1:(0.1-0.5):(0.01-10), and more preferably 1:(0.1-0.5):(0.01-1).

[0019] According to the present invention, preferably, the mass ratio of the surfactant to the polymer is 1:(0.1-1), preferably 1:(0.1-0.5). For example, it can be 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, and the ratio of 1 to any value between 0.1 and 0.5 or any interval between any two values.

[0020] According to the present invention, preferably, the mass ratio of the surfactant to the amino organic compound is 1:(0.01-100), preferably 1:(0.01-10), more preferably 1:(0.01-1), for example, it can be 1:0.01, 1:0.04, 1:0.08, 1:0.12, 1:0.15, 1:0.2, 1:0.4, 1:0.6, 1:0.8, 1:1, and the ratio of 1 to any value between 0.01 and 1 or any interval between any two values.

[0021] According to the present invention, the oil displacement composition contains an oil displacement agent and an oil displacement auxiliary agent; wherein the oil displacement agent includes a surfactant, a polymer and an amino organic compound, in which case a better technical effect is achieved. In a preferred embodiment of the present invention, the oil displacement composition also includes a low-carbon organic cationic compound.

[0022] The selection range of the low-carbon organic cationic compound is relatively wide. In a more preferred embodiment of the present invention, the low-carbon organic cationic compound is selected from quaternary ammonium salts having C1-C4 groups and / or quaternary ammonium bases having C1-C4 groups; preferably, the C-containing groups connected to N in each of the quaternary ammonium salts and quaternary ammonium bases are C1-C4 groups; more preferably, the C1-C4 groups are C1-C4 hydrocarbon groups or C1-C4 cycloalkyl groups; further more preferably, the number of C atoms in the low-carbon organic cationic compound is less than 16; further more preferably, the low-carbon organic cationic compound is selected from at least one of glycidyltrimethylammonium chloride, trimethylallylammonium chloride, tetramethylammonium chloride and ethyltrimethylammonium chloride.

[0023] According to the present invention, when the oil displacement composition includes a low-carbon organic cationic compound, the selection range of the ratio of each component is relatively wide. In a preferred embodiment of the present invention, the mass ratio of the surfactant, polymer, amino organic compound and low-carbon organic cationic compound is 1: (0.1-1): (0.01-100): (0.01-100), preferably 1: (0.1-0.5): (0.01-10): (0.01-10), more preferably 1: (0.1-0.5): (0.01-1): (0.01-1); further more preferably 1: (0.1-0.5): (0.01-0.5): (0.01-0.5).

[0024] According to the present invention, preferably, the mass ratio of the surfactant, the polymer, the amino organic compound and the low-carbon organic cationic compound is 1: (0.1-1): (0.01-100): (0.01-100), preferably 1: (0.1-0.5): (0.01-10): (0.01-10), more preferably 1: (0.1-0.5): (0.01-1): (0.01-1), and further more preferably 1: (0.1-0.5): (0.01-0.5): (0.01-0.5); for example, the mass ratio of the surfactant to the polymer in the present invention is 1 to 0.1, 0.2, 0 .3, 0.4, 0.5 and any value between 0.1 and 0.5 or the ratio of any two values, and the mass ratio of the surfactant to the amino organic compound is 1 and 0.01, 0.04, 0.06, 0.08, 0.12, 0.2, 0.3, 0.4, 0.5 and any value between 0.01 and 0.5 or the ratio of any two values, and the mass ratio of the surfactant to the low-carbon organic cationic compound is 1 and 0.01, 0.04, 0.06, 0.08, 0.12, 0.2, 0.3, 0.4, 0.5 and any value between 0.01 and 0.5 or the ratio of any two values.

[0025] According to the present invention, when the surfactant in the surfactant composition is selected from a compounded surfactant, in the above-mentioned ratio, the weight of the surfactant refers to the total weight of the cationic surfactant and the anionic surfactant (including anionic-nonionic surfactant).

[0026] The second object of the present invention is to provide a method for preparing an oil displacement composition, comprising mixing components including a surfactant, a polymer, an amino organic compound and an optional low-carbon organic cationic compound.

[0027] The third object of the present invention is to provide an oil displacement fluid for oil fields, comprising the above-mentioned oil displacement composition and water.

[0028] According to the present invention, the ratio selection range of the oil displacement fluid for oil fields is relatively wide. In a preferred embodiment of the present invention, the mass ratio of the total mass of the surfactant, the amino organic compound and the optional low-carbon organic cationic compound in the oil displacement composition to water is not greater than 10:100; preferably (0.05-5):100.

[0029] According to the present invention, the mineralization range of water in the oil displacement fluid applicable to the present invention is relatively wide, for example, the mineralization of the water can be 0-25%, wherein the mineralization of the water is 0-25%, which refers to the mass concentration.

[0030] According to the present invention, the oil displacement fluid for oil field of the present invention can be obtained by mixing components including water, surfactant, polymer, amino organic compound and optional low-carbon organic cationic compound.

[0031] A fourth object of the present invention is to provide an application of the above-mentioned oil displacement composition or the above-mentioned oil field displacement fluid in oil field exploitation.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] The oil displacement composition has high solubilization and permeability performance, and is particularly suitable for heterogeneous oil fields with high clay content and heterogeneous oil fields with high water content and high recovery degree. Under complex reservoir conditions with certain slugs, it still has a high final recovery rate, improves the enhanced recovery rate of the complex working conditions, and has better adaptability. The oil displacement composition of the present invention can significantly reduce the damage of colloid asphaltene and clay expansion to the core, and has a low core damage rate.

[0034] The inventors of the present invention have found through research that the reason for the following advantages may be:

[0035] (1) With the synergistic cooperation of surfactants and amino organic compounds, the seepage capacity of low-permeability reservoirs is improved while the solubilization performance is enhanced. On this basis, the polymer controls the fluidity, so that the oil displacement composition can better act on the reservoir.

[0036] (2) With the synergistic combination of surfactants, polymers and amino organic compounds, the injection requirements of low-permeability cores are met, the fluidity is controlled, and the solubility of the surfactant system is improved.

[0037] As described above, with the synergistic combination of surfactant, polymer and amino organic compound, the oil displacement composition of the present invention still has a high ultimate recovery rate and enhanced recovery rate even under the working conditions of a heterogeneous oil field with high clay content and a heterogeneous oil field with high water content and high recovery degree. DETAILED DESCRIPTION

[0038] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the contents of the present invention still fall within the scope of protection of the present invention.

[0039] According to the process of Example 1 of CN101279935A, the difference is that step (2) is not performed, and step (3) is directly performed after step (1) to obtain the anionic-nonionic surfactant of the present invention. Specifically, nonylphenol, dodecylphenol and isotridecyl alcohol are used as raw materials to obtain nonylphenol polyoxyethylene ether carboxylate sodium, dodecylphenol polyoxyethylene ether carboxylate sodium and isotridecyl alcohol polyoxyethylene ether carboxylate sodium in the embodiment.

[0040] In the following examples, polyacrylamide was purchased from Aisen Co., Ltd. Other raw materials used in the examples, if not specifically limited, are disclosed in the prior art, for example, they can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0041] In the embodiments and comparative examples, the oil-water interfacial tension is determined using an American TX-500C rotating drop interfacial tension meter. The phase state experiment is mainly carried out by the glass capillary method. A certain amount of surfactant solution and crude oil are successively added to a capillary sealed at one end according to a water-to-oil ratio (WOR) of 1:1, and the liquid levels of the surfactant solution and crude oil and the mass of each added are recorded. The glass capillary is then sealed with an acetylene-oxygen flame or epoxy resin glue and immersed in a 10 ml oil bath glass test tube filled with silicone oil, and placed in a metal bath (Hanuo Instruments) and heated at a reservoir temperature of 52°C. The test tube must first be manually or mechanically shaken to mix the oil and water phases evenly, and then balanced in a constant temperature metal bath for several days to weeks until the oil and water levels no longer change. The solubilization parameters (SP) of the oil phase and the water phase can be calculated based on the changes in the oil-water interface level in the microemulsion:

[0042]

[0043] Where V i is the volume of the aqueous or oil phase in the microemulsion, V s is the volume of surfactant. There are three assumptions in the calculation of SP parameters: the total volume of oil and water remains unchanged after mixing; all surfactants are in the microemulsion phase; the volume of surfactant is equal to its mass.

[0044] The contact angle on the core was measured using a German Kruess DSA100 contact angle meter.

[0045] In the embodiment, the static adsorption amount of the surfactant is measured by mixing the surfactant solution with simulated sand (90% 80-100 mesh quartz sand + 10% kaolin) in a mass ratio of 3:1, and placing it in a constant temperature water bath (reservoir temperature, rotation speed 170r / min) for 24h.

[0046] In the embodiment, a cylindrical artificial sandstone core with a diameter of 25 mm and a length of 80 mm was used for core displacement test. The core is formed by pressing quartz sand with a certain particle size distribution and 10% kaolin with a binder (provided by Hai'an County Petroleum Research Instrument Co., Ltd.). The core porosity is 25%, and the permeability (if there is no special instruction, it is 50md. If there is a special instruction, the actual permeability corresponding to the embodiment shall prevail) The core is first saturated with formation water and then replaced by crude oil. After that, the maximum oil saturation is obtained by exchanging the injection end and the outlet end until no replacement brine is observed in the produced fluid. The initial oil content in the core is obtained according to the change in the core weight. The core is then aged for 10 days at the reservoir temperature. The fluid injection rate is 0.1mL / min. The injection sequence is as follows:

[0047] Water flooding: inject salt water into the formation until no crude oil is found in the water. The water flooding recovery factor is calculated based on the ratio of the amount of crude oil displaced to the initial oil content.

[0048] Chemical flooding: 0.5 pore volume (PV) of SP was injected. SP was 0.3 wt% surfactant mixture and 0.10 wt% polyacrylamide.

[0049] Post-water flooding: Re-inject water until no crude oil is found in the water. The final recovery factor is obtained based on the ratio of the total amount of crude oil displaced to the initial oil content.

[0050] The difference between the final recovery factor and the water drive recovery factor is the chemical drive enhanced recovery factor.

[0051] [Examples 1-4] and [Comparative Example 1]

[0052] Octylphenol polyoxyethylene ether sodium carboxylate (anionic surfactant), dodecyltrimethylammonium chloride (cationic surfactant), 1,2-propylenediamine and trimethylallyl ammonium chloride are prepared into a surfactant composition in a certain proportion.

[0053] The formula of the oil displacement fluid is shown in Table 1, which contains a polymer, a surfactant composition and water. The contents of the polymer and the surfactant composition in Table 1 are in mass %. The polymer is polyacrylamide with a molecular weight of 8 million produced by Aisen Company. Surfactant composition 1, surfactant composition 2 and surfactant composition 3 are composed of a yin-yang compound surfactant (the molar ratio of sodium octylphenol polyoxyethylene ether carboxylate to dodecyltrimethylammonium chloride is 8:3), 1,2-propylenediamine and trimethylallyl ammonium chloride in mass ratios of (1:0:0), (1:0.4:0) and (1:0.4:0.1), respectively.

[0054] The core displacement experiment was conducted at 20°C with a salinity of 0.5% for the oil displacement fluid. The results are shown in Table 1.

[0055] Table 1

[0056]

[0057] The results show that under low permeability conditions (permeability 20MD), the recovery rate of the single cation-cation surfactant combined with the polymer increased by 4.6%, the recovery rate of amino organic compounds increased to 10.5%, and the recovery rate increased to 15.4% by further adding low-carbon organic cationic compounds.

[0058] [Examples 5-8] and [Comparative Example 2]

[0059] Dodecylphenol polyoxyethylene ether sodium sulfate (anionic surfactant), tetradecyltrimethylammonium chloride (cationic surfactant), triethylamine and tetramethylammonium chloride are prepared into a surfactant composition according to a certain ratio, and an anionic and cationic surfactant (the molar ratio of anionic and cationic surfactants is 7.3:2.7).

[0060] The formula of the oil displacement fluid is shown in Table 2, which contains a polymer (polyacrylamide with a molecular weight of 12 million produced by Aisen Company), a surfactant composition and water. The contents of the polymer and the surfactant composition in Table 2 are in mass %.

[0061] The polymer is polyacrylamide, and the surfactant composition 1, the surfactant composition 2, and the surfactant composition 3 are composed of a yin-yang compound surfactant (the molar ratio of sodium dodecylphenol polyoxyethylene ether sulfate to tetradecyltrimethylammonium chloride is 7.3:2.7), triethylamine, and tetramethylammonium chloride in proportions of (1:0:0), (1:0.2:0), and (1:0.2:0.1), respectively.

[0062] The salinity of the oil displacement fluid was 0.5%, and the core displacement experiment was carried out at 80°C. The results are shown in Table 2.

[0063] Table 2

[0064]

[0065] The results in Table 2 show that under low permeability conditions (permeability 20MD), the recovery factor of the single cation-cation surfactant combined with the polymer increased by 8.7%, the recovery factor of amino organic compounds increased to 11.2%, and the recovery factor of low-carbon organic cationic compounds increased to 19.7%.

[0066] In Example 9, a heterogeneous model (25×80 mm, porosity: 25%) in an artificial layer with a permeability difference of 3 times (20 mD / 60 mD) was used to examine the oil displacement effect of the composition in the heterogeneous core. It can be seen that the oil displacement fluid of the present invention also has a good oil displacement effect under the heterogeneous core working condition.

[0067] [Examples 10-11] and [Comparative Examples 3-4]

[0068] Sodium alkylphenol polyoxyethylene ether sulfonate, hexadecyltrimethylammonium chloride (molar ratio 7:1.5), isobutylamine and glycidyltrimethylammonium chloride are prepared into a surfactant composition in a certain proportion.

[0069] The formula of the oil displacement fluid is shown in Table 3, which contains a polymer (polyacrylamide with a molecular weight of 10 million produced by Aisen Company), a surfactant composition and water. The contents of the polymer and the surfactant composition in Table 3 are in mass %. The polymer is polyacrylamide, and the surfactant composition 1, the surfactant composition 2 and the surfactant composition 3 are composed of a yin-yang composite surfactant (sodium alkylphenol polyoxyethylene ether sulfonate + hexadecyltrimethylammonium chloride), isobutylamine and glycidyltrimethylammonium chloride in proportions of (1:0:0), (1:0.05:0) and (1:0.05:0.05), respectively.

[0070] The salinity of the oil displacement fluid was 0.5%, and the core displacement experiment was carried out at 90°C. The results are shown in Table 3.

[0071] Table 3

[0072]

[0073] The results show that under low permeability conditions (permeability 20MD), the recovery rate of the single cation-cation surfactant combined with the polymer is 2.3%, which is a low recovery rate. The recovery rate is increased to 8.5% by adding amino organic compounds, and the recovery rate is increased to 15.4% by further adding low-carbon organic cationic compounds.

[0074] [Example 12]

[0075] Based on water, 0.3wt% surfactant composition (anionic and cationic surfactant (sodium dodecylphenol polyoxyethylene ether sulfate and tetradecyl trimethyl ammonium chloride in a molar ratio of 7.3:2.7), benzylamine and tetramethyl ammonium chloride in a mass ratio of 1:0.2:0.1) was compounded with 0.1wt% polyacrylamide (polyacrylamide with a molecular weight of 8 million produced by Aisen Company); at 80°C, the solution mineralization was 0.8%, and the oil-water interfacial tension was measured to be 1.5×10 -4 Mn / m, the capacity expansion parameter reaches 24.0, and the static adsorption capacity is 1.75 mg / g.

[0076] It can be seen that the oil-water interfacial tension of the oil displacing agent after being matched with the polymer does not change much, the solubilization parameter is further improved, and the static adsorption amount remains stable, which proves that the surfactant composition has good compatibility with the polymer.

[0077] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. An oil displacement composition comprising a surfactant, a polymer and an amino organic compound; The surfactant contains anionic surfactant and cationic surfactant; The anionic surfactant is an anionic-nonionic surfactant; the anionic-nonionic surfactant is selected from alkyl polyether carboxylates and / or polyether sulfonates; The cationic surfactant is selected from a quaternary ammonium salt having a C4-C22 alkyl group and / or a quaternary ammonium base having a C4-C22 alkyl group; The amino organic compound is selected from at least one of diethylamine, triethylamine, isopropylamine, 1,3-propylenediamine, 1,2-propylenediamine, tripropylamine, butylamine, isobutylamine and tert-butylamine; The polymer is selected from water-soluble polyacrylamide; The oil displacement composition further comprises a low-carbon organic cationic compound; the low-carbon organic cationic compound is at least one selected from the group consisting of glycidyltrimethylammonium chloride, trimethylallylammonium chloride, tetramethylammonium chloride and ethyltrimethylammonium chloride; The molar ratio of the cationic surfactant to the anionic-nonionic surfactant is 1:(0.01-100); The mass ratio of the surfactant, the polymer, the amino organic compound and the low-carbon organic cationic compound is 1:(0.1-1):(0.01-100):(0.01-100).

2. The oil displacement composition according to claim 1, characterized in that: The molar ratio of the cationic surfactant to the anionic-nonionic surfactant is 1:(0.1-10).

3. The oil displacement composition according to claim 1, characterized in that: The mass ratio of the surfactant, the polymer and the amino organic compound is 1:(0.1-0.5):(0.01-10).

4. The oil displacement composition according to claim 1, characterized in that: The mass ratio of the surfactant, the polymer, the amino organic compound and the low-carbon organic cationic compound is 1:(0.1-0.5):(0.01-10):(0.01-10).

5. The oil displacement composition according to claim 1, characterized in that: The mass ratio of the surfactant, the polymer, the amino organic compound and the low-carbon organic cationic compound is 1:(0.1-0.5):(0.01-1):(0.01-1).

6. A method for preparing the oil displacement composition according to any one of claims 1 to 5, comprising mixing components including a surfactant, a polymer, an amino organic compound and a low-carbon organic cationic compound.

7. An oil displacement fluid for oil fields, comprising the oil displacement composition according to any one of claims 1 to 5 and water.

8. The oil field displacement fluid according to claim 7, characterized in that: The mass ratio of the total mass of the surfactant, the amino organic compound and the low-carbon organic cationic compound in the oil displacement composition to the mass of water is not greater than 10:100; And / or, the mineralization degree of the water is 0-25%.

9. The oil field displacement fluid according to claim 8, characterized in that: The mass ratio of the total mass of the surfactant, the amino organic compound and the low-carbon organic cationic compound in the oil displacement composition to water is (0.05-5):

100.

10. Use of the oil displacement composition according to any one of claims 1 to 5 or the oil displacement fluid for oil field according to any one of claims 7 to 9 in oil field exploitation.

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