Amphiphilic uniform osmotic oil-displacing agent, preparation method and application, and enhanced oil recovery method

Abstract

This invention discloses an amphiphilic uniform penetration inhibitor oil displacement agent, its preparation method, its application, and a method for improving oil recovery. The preparation method of the amphiphilic uniform penetration inhibitor oil displacement agent comprises the following steps: In the presence of an initiator and a solvent, sodium styrene sulfonate, acrylamide, N-ethoxymethyl-N-isobutoxymethylacrylamide, and 3-acetamino-N-ethyl-N,N-dimethylpropyl-1-amine undergo a solution polymerization reaction. The molar ratio of sodium styrene sulfonate, acrylamide, N-ethoxymethyl-N-isobutoxymethylacrylamide, and 3-acetamino-N-ethyl-N,N-dimethylpropyl-1-amine is 1:0.01–25:0.01–50:0.01–50. The solution polymerization reaction results in an amphiphilic uniform penetration inhibitor oil displacement agent with a viscosity-average molecular weight of 35 million to 40 million.

Description

Technical Field

[0001] This invention belongs to the field of petroleum engineering and relates to the chemical viscosity reduction and flooding development technology for cold production of heavy oil reservoirs. Specifically, it relates to amphiphilic uniform permeability inhibition flooding agents and their preparation methods and applications, as well as methods to enhance oil recovery. Background Technology

[0002] Heavy oil extraction is challenging and energy-intensive, but it holds irreplaceable value in processing high-grade transformer oil, aerospace rocket kerosene, and high-grade asphalt. With the massive consumption of conventional oil and gas resources and the continuous increase in petroleum demand, heavy oil resources, characterized by their wide distribution, enormous reserves, and low utilization rate, have become the main focus of future development. China possesses abundant heavy oil resources, accounting for over 20% of its total petroleum resources, with proven reserves of 43.5 × 10⁻⁶. 8 The proven geological reserves of heavy oil in Shengli Oilfield are currently 6.4 × 10⁻⁶. 8 t, of which the proven geological reserves of heavy oil in the eastern oilfield are 5.89 × 10 8 t, currently 4.69×10 8 t; The Chunfeng Oilfield and Chunhui Oilfield were successively discovered in the western oilfield, with proven geological reserves of approximately 8029×10 4 t, currently 4264×10 4 Shengli heavy oil has an annual output of over 6.2 million tons, accounting for more than a quarter of the total output. The main extraction methods are steam injection and water drive.

[0003] Heavy oil cold production technology can effectively compensate for the shortcomings of thermal production. In particular, chemical viscosity reduction composite development technology can reduce the interfacial tension between oil and water and emulsify and disperse heavy oil after being injected into the oil layer, forming an "oil-in-water" emulsion. It has the characteristics of high viscosity reduction rate, low cost and easy operation.

[0004] In recent years, Shengli Oilfield has been continuously exploring cold recovery technology for heavy oil, and has achieved certain development results in the field. However, water-driven heavy oil is prone to viscous fingering and water channeling due to the influence of the oil-water mobility ratio, resulting in low efficiency. Direct application of viscosity reducers can be observed to show that the viscosity reducer solution migrates along the dominant seepage channels, with limited improvement in oil displacement effect. The remaining oil is mainly in clusters in unaffected areas, characterized by overall enrichment and partial dispersion, with 50-70% of the remaining oil remaining untouched. High viscosity and large oil-water mobility ratio result in a small water-driven affected volume and low recovery rate (approximately 17.6%). The distribution of remaining oil changes from continuous network and clusters to droplets and films, with severe water channeling, making it difficult to increase oil production and improve recovery rate.

[0005] The key to improving heavy oil recovery lies in the extent to which the displacing fluid expands the swept volume and the efficiency of oil washing. Conventional heavy oil viscosity reducers and displacement agents have good interfacial activity and emulsification ability in the formation, and can strip crude oil adhering to the rock surface to form an O / W type emulsion. However, the seepage resistance generated by the emulsion during the displacement process is limited. The displacing fluid preferentially enters the fracture channels with high permeability and large porosity, and it is difficult to reach the low-permeability microfracture reservoirs. These unaffected reservoirs are still in a high oil-bearing state. At present, conventional heavy oil viscosity reducers and displacement agents have a very limited effect on improving crude oil recovery.

[0006] Chinese invention patent CN110627930B relates to a method for preparing and using a polymer viscosity reducer for heavy oil. The preparation method includes the following steps: (1) dissolving acrylamide and sodium α-olefin sulfonate in deionized water to form an aqueous solution; (2) adding a redox initiation system to the aqueous solution at an elevated temperature, for example, 50-70°C, and continuously stirring at a low speed to obtain the polymer viscosity reducer. However, the above technical solution still has the following shortcomings: This patent mainly focuses on developing an active polymer viscosity reducer to address the problems of excessive energy consumption for heating viscosity reduction and excessive cost of dilution viscosity reduction during heavy oil extraction. The oil displacement method is too simple, the seepage resistance is limited, and there is no formulation optimization for the remaining oil conditions in difficult-to-extract heavy oil reservoirs, resulting in a very low increase in recovery rate.

[0007] Chinese invention patent CN112592430B discloses a low-surface-activity polymer thick oil viscosity reducer, its preparation method, and its application. The preparation method involves the following steps: acryloylmorpholine and maleic anhydride, or with the addition of N-(3-hydroxypropyl)-N-(3-methoxypropyl)acrylamide, are first subjected to free radical copolymerization, followed by reaction with sodium hydroxide to finally obtain the low-surface-activity polymer thick oil viscosity reducer. The viscosity reducer system disclosed in this patent has an aqueous solution with too low an apparent viscosity, making it unsuitable for uniform displacement and expanding the sweep area. Summary of the Invention

[0008] Technical Problem: The distribution of remaining oil in the Shengli Oilfield has shifted from continuous network and cluster patterns to isolated droplets and films, resulting in severe water channeling and complex reservoir fluid flow conditions, making it difficult to increase oil production and improve oil recovery. For chemical viscosity reduction of difficult-to-recover heavy oil, the key to improving oil recovery lies in expanding the swept volume of the displacing phase and improving oil washing efficiency. Conventional heavy oil viscosity reducers have limited seepage resistance generated by the emulsion during the displacement process. The displacing fluid preferentially enters the high-permeability, high-porosity fracture channels and has difficulty reaching low-permeability microfracture reservoirs. These unaffected reservoirs remain in a high-oil-content state, and currently, conventional heavy oil viscosity reducers have very limited effect on improving crude oil recovery. There is an urgent need to provide chemical viscosity reducers for difficult-to-recover heavy oil with uniform permeability and resistance, as well as methods to improve oil recovery. By continuously injecting high-efficiency oil displacement agents, continuous sweep expansion can be achieved with low concentration and high efficiency, significantly improving the recovery rate of cold chemical flooding of heavy oil.

[0009] To address the shortcomings of existing technologies, this invention discloses an amphiphilic homogeneous permeability-inhibiting oil displacement agent, its preparation method, and its application, as well as a method for improving oil recovery. This invention utilizes a homogeneous permeability-inhibiting heavy oil chemical flooding cold recovery method centered on "fluid flow diversion, mobility control, and staged adjustment," transforming the process from single-stage oil displacement to a combined approach of downsinking, adjustment, and washing, significantly improving the recovery rate of inefficient water-driven heavy oil reservoirs. Specifically:

[0010] Amphiphilic, uniformly penetrating, and anti-fouling oil displacement agents, at a concentration of 1%, achieve a viscosity reduction rate of over 90% for extra-heavy oils. At a working concentration of 1000 mg / L, with a total mineralization exceeding 30000 mg / L, Ca... 2+ Mg 2+ Ion concentration greater than 500 mg / L, apparent viscosity greater than 150 mPa·s, effective utilization of residual oil in low-permeability zones, and plugging rate ≥ 90%.

[0011] Technical solution: An amphiphilic uniform penetration inhibitor oil displacement agent, wherein the amphiphilic uniform penetration inhibitor oil displacement agent contains structural unit A, structural unit B, structural unit C and structural unit D, the structural formula of structural unit A is shown in formula (1), the structural formula of structural unit B is shown in formula (2), the structural formula of structural unit C is shown in formula (3), and the structural formula of structural unit D is shown in formula (4), wherein:

[0012] The molar ratio of structural unit A, structural unit B, structural unit C and structural unit D is (2000~20000): (2000~40000): (4000~60000): (6000~100000);

[0013] a is a positive integer from 1 to 4, preferably a positive integer from 2 to 3;

[0014] b is a positive integer from 2 to 7, preferably a positive integer from 3 to 6;

[0015] c is a positive integer from 1 to 15, preferably a positive integer from 8 to 12;

[0016] The viscosity-average molecular weight of the amphiphilic homogeneous penetration inhibitor is 35 million to 40 million.

[0017]

[0018]

[0019] The preparation method of the above-mentioned amphiphilic uniform penetration-resistant oil displacement agent includes the following steps:

[0020] In the presence of an initiator and a solvent, sodium styrene sulfonate, acrylamide, N-ethoxymethyl-N-isobutoxymethylacrylamide, and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine are subjected to solution polymerization, wherein:

[0021] The molar ratio of sodium styrene sulfonate, acrylamide, N-ethoxymethyl-N-isobutoxymethacryloyl and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine (CAS No.: 123-83-1) is 1:0.01~25:0.01~50:0.01~50;

[0022] The solution polymerization reaction results in an amphiphilic uniform permeation-resistant oil displacement agent with a viscosity-average molecular weight of 35 million to 40 million.

[0023] The amphiphilic uniform penetration inhibitor oil displacement agent is prepared by the above-described preparation method.

[0024] Application of amphiphilic uniform permeability-inhibiting oil displacement agents as chemical viscosity reducers in cold production of inefficient water-driven heavy oil reservoirs.

[0025] The steps to improve the recovery rate are as follows:

[0026] (1) Screening of target inefficient water-driven heavy oil blocks;

[0027] (2) Inject the plugging agent;

[0028] (3) Continuously inject the above-mentioned amphiphilic uniform penetration inhibitory oil displacement agent;

[0029] (4) Continuous production after well opening.

[0030] The technical approach of this invention is as follows:

[0031] First, a plugging agent is injected to seal the large outlet channels and reduce the water content of the produced fluid.

[0032] Then, an amphiphilic uniform permeability-resistant oil displacement agent is injected to disperse larger oil droplets into smaller ones, block the main channel, reduce permeability, expand the affected area, and effectively utilize the remaining oil in small pores. From a microscopic perspective, the interface adhesion sweeping and expansion of microscopic affected area are achieved through a net-like sweeping solubilization drag force and a step-by-step adjustment of the pulsating pulse. From a macroscopic perspective, the force field diversion and macroscopic capacity expansion of the flow field are achieved by using uniform permeability-resistant full-domain excitation, ultimately achieving uniform permeability-resistant control.

[0033] By continuously injecting a highly efficient amphiphilic uniform permeability-resistant oil displacement agent, continuous diffusion is achieved. This low-concentration, high-efficiency method avoids the shortcomings of conventional heavy oil viscosity-reducing oil displacement agents, such as large dosage, high concentration, and poor injectability. Based on continuous injection, the effective oil well is pumped into the well for continuous oil production, significantly improving the recovery rate of heavy oil cold chemical flooding.

[0034] This invention addresses the shortcomings of existing technologies by providing a chemical viscosity-reducing, permeability-increasing, and anti-oil-restricting agent for difficult-to-recover heavy oil, along with a method to enhance oil recovery. Through a chemical flooding method for cold recovery of heavy oil with permeability-increasing and anti-oil-restricting properties, centered on "fluid flow diversion, mobility control, and staged adjustment," the method transforms the oil recovery process from a single oil displacement method to a combined oil displacement method involving viscosity reduction, adjustment, and washing, significantly improving the recovery rate of inefficient water-flooded heavy oil reservoirs. The invented amphiphilic permeability-increasing and anti-oil-restricting agent, at a concentration of 1%, achieves a viscosity reduction rate of over 90% for extra-heavy oil. At a working concentration of 1000 mg / L, with a total salinity exceeding 30000 mg / L, the Ca... 2+ Mg 2+ Ion concentration greater than 500 mg / L, apparent viscosity greater than 150 mPa·s, effective utilization of residual oil in low-permeability zones, and plugging rate ≥ 90%.

[0035] Effects of the Invention: The amphiphilic uniform permeability-inhibiting oil displacement agent, its preparation method, and its application, as well as the method for improving oil recovery disclosed in this invention, have the following beneficial effects:

[0036] (1) The amphiphilic uniform penetration inhibitor is based on an acrylamide skeleton, with the introduction of a small amount of amphiphilic groups N-ethoxymethyl-N-isobutoxymethylacrylamide and hydrophobic groups 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine and surface-active groups sodium styrenesulfonate.

[0037] N-ethoxymethyl-N-isobutoxymethylacrylamide exhibits both hydrophilic and hydrophobic properties, is soluble in water and organic solvents, and can effectively reduce oil-water interfacial tension.

[0038] The hydrophobic group 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine enables amphiphilic polymers to associate in solution to form a three-dimensional structure, increasing the viscoelasticity of the dispersion system.

[0039] Sodium styrene sulfonate enables amphiphilic polymers to possess surface-active properties. The sulfonic acid groups have strong salt resistance, which can resist salt ions contained in the formation and improve stability.

[0040] (2) The amphiphilic uniform penetration inhibitor oil displacement agent, at a concentration of 1%, achieved a viscosity reduction rate of over 90% for extra-heavy oils. At a working concentration of 1000 mg / L, with a total mineralization exceeding 30000 mg / L, Ca... 2+ Mg 2+ Ion concentration greater than 500 mg / L, apparent viscosity greater than 150 mPa·s, effective utilization of residual oil in low-permeability zones, and plugging rate ≥ 90%.

[0041] (3) Inefficient water-driven heavy oil reservoirs employ a cold production method with continuous injection of amphiphilic homogeneous flow inhibitors. Microscopically, a net-like sweeping activity enhancement is used to overcome the problem of homogeneous fluid central channel intrusion. The net-like volume exclusively drives away residual oil, and the drag force pulls away the active solubilizing residual oil. At the same time, the leaping pulse flow direction is used to achieve temporary retention and flow rate regulation, effectively blocking the dominant seepage channels and changing the flow direction to expand the swept volume. Macroscopically, the force field flood diversion flow rate control is used to achieve temporary retention and distribution regulation. The net-like retention forms an oil band, expanding the swept volume at both the micro and macro levels. The global excitation stepwise regulation and drive is used to achieve stepwise regulation and drive to expand the swept volume. The bridging network retention and temporary retention change the flow direction, and the elastic deformation leaping action sweeps away residual oil.

[0042] (4) This invention transforms the single-stage oil displacement into a combined oil displacement method involving reduction, adjustment, and washing, significantly improving the recovery rate of water-driven heavy oil reservoirs. The amphiphilic, uniformly permeable oil displacement agent, at a concentration of 1%, achieves a viscosity reduction rate of over 90% for extra-heavy oil, effectively utilizing the remaining oil in low-permeability zones, with a plugging rate ≥90%. Based on field test data, this method enables efficient development of inefficient water-driven heavy oil reservoirs, reducing water cut by over 10%, increasing oil production by an average of over 4 tons per day per well, and achieving an input-output ratio higher than 1:4. Attached Figure Description

[0043] Figure 1 Flowchart of methods to improve oil recovery

[0044] Figure 2 A schematic diagram of the drug dosage calculation model

[0045] Figure 3 The infrared spectrum of the amphiphilic uniform permeation-resistant oil displacement agent prepared in Example 1 of the present invention.

[0046] Figure 4 This is a schematic diagram illustrating the oil displacement effect of the sample JSZ-1 ​​of the present invention.

[0047] Figure 5 This is a schematic diagram illustrating the oil displacement effect of the JNQY sample for comparison. Detailed Implementation

[0048] The specific embodiments of the present invention are described in detail below.

[0049] The "range" disclosed in this invention is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 10–50 is listed for a specific parameter, it is also expected that ranges of 10–40 and 20–50 are also included. Furthermore, if the minimum range values ​​are 1 and 2, and the maximum range values ​​are 3, 4, and 5, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, unless otherwise stated, the numerical range "a–b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0–5" means that all real numbers between "0–5" have been listed herein; "0–5" is merely a shortened representation of these numerical combinations.

[0050] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0051] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0052] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0053] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0054] Unless otherwise specified, the reaction will proceed under normal temperature and pressure conditions.

[0055] Unless otherwise specified, all parts or percentages are by weight or by weight percentage.

[0056] In this invention, all the substances used are known substances that can be purchased or synthesized by known methods.

[0057] In this invention, all the devices or equipment used are conventional devices or equipment known in the art and are readily available.

[0058] The equation for the synthesis reaction of the amphiphilic uniform penetration-blocking oil displacement agent is as follows:

[0059]

[0060] An amphiphilic uniformly penetrating oil displacement agent, wherein the amphiphilic uniformly penetrating oil displacement agent contains structural unit A, structural unit B, structural unit C and structural unit D, the structural formula of structural unit A is shown in formula (1), the structural formula of structural unit B is shown in formula (2), the structural formula of structural unit C is shown in formula (3), and the structural formula of structural unit D is shown in formula (4), wherein:

[0061] The molar ratio of structural unit A, structural unit B, structural unit C and structural unit D is (2000~20000): (2000~40000): (4000~60000): (6000~100000);

[0062] a is a positive integer from 1 to 4, preferably a positive integer from 2 to 3;

[0063] b is a positive integer from 2 to 7, preferably a positive integer from 3 to 6;

[0064] c is a positive integer from 1 to 15, preferably a positive integer from 8 to 12;

[0065] The viscosity-average molecular weight of the amphiphilic homogeneous penetration inhibitor is 35 million to 40 million.

[0066]

[0067] Furthermore, the general structural formula of the amphiphilic uniform penetration-resistant oil displacement agent is as follows:

[0068] in:

[0069] m is a positive integer from 2000 to 20000, preferably a positive integer from 10000 to 15000;

[0070] n is a positive integer from 2000 to 40000, preferably a positive integer from 20000 to 40000;

[0071] p is a positive integer from 4000 to 60000, preferably a positive integer from 10000 to 60000;

[0072] q is a positive integer from 6000 to 100000, preferably a positive integer from 10000 to 80000;

[0073] a is a positive integer from 1 to 4, preferably a positive integer from 2 to 3;

[0074] b is a positive integer from 2 to 7, preferably a positive integer from 3 to 6;

[0075] c is a positive integer from 1 to 15, preferably a positive integer from 8 to 12;

[0076] The viscosity-average molecular weight of the amphiphilic uniform permeation-resistant oil displacement agent is 35 million to 40 million.

[0077] The preparation method of the above-mentioned amphiphilic uniform penetration-resistant oil displacement agent includes the following steps:

[0078] In the presence of an initiator and a solvent, sodium styrene sulfonate, acrylamide, N-ethoxymethyl-N-isobutoxymethylacrylamide, and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine are subjected to solution polymerization, wherein:

[0079] The molar ratio of sodium styrene sulfonate, acrylamide, N-ethoxymethyl-N-isobutoxymethacryloyl and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine (CAS No.: 123-83-1) is 1:0.01~25:0.01~50:0.01~50;

[0080] The solution polymerization reaction results in an amphiphilic uniform permeation-resistant oil displacement agent with a viscosity-average molecular weight of 35 million to 40 million.

[0081] Further, the molar ratio of the sodium styrene sulfonate, the acrylamide, N-(3-hydroxypropyl)-N-(3-methoxypropyl)acrylamide and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine is 1:5~10:20~40:20~40.

[0082] Further, the initiator is one of benzoyl peroxide / sucrose, tert-butyl hydroperoxide / sodium thiosulfate, tert-butyl hydroperoxide / sodium metabisulfite, benzoyl peroxide / N,N-dimethylaniline, ammonium persulfate / sodium bisulfite, and / or

[0083] The amount of initiator used is 0.01-0.5% of the amount of acrylamide used;

[0084] If the initiator is benzoyl peroxide / sucrose, the mass ratio of benzoyl peroxide to sucrose is 1:0.5 to 0.8;

[0085] If the initiator is tert-butyl hydroperoxide / sodium benzoate, the mass ratio of tert-butyl hydroperoxide to sodium benzoate is 1:2 to 5.

[0086] If the initiator is tert-butyl hydroperoxide / sodium metabisulfite, the mass ratio of tert-butyl hydroperoxide to sodium metabisulfite is 1:0.5 to 1.0;

[0087] If the initiator is benzoyl peroxide / N,N-dimethylaniline, the mass ratio of benzoyl peroxide to N,N-dimethylaniline is 1:1 to 4;

[0088] If the initiator is ammonium persulfate / sodium bisulfite, the mass ratio of ammonium persulfate to sodium bisulfite is 1:0.8 to 1.2.

[0089] Furthermore, the solvent is one or more of toluene, xylene, benzene, ethyl acetate, and butyl acetate, and / or

[0090] The amount of solvent used is 0.8 to 5 times the total mass of the monomers.

[0091] Furthermore, a surfactant is added during the reaction process. The surfactant is one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, Tween-80, Tween-60, and Tween-90, wherein:

[0092] The amount of surfactant added in step (1) is 5%-10% of the sum of the masses of all monomers.

[0093] The preparation method of the above-mentioned amphiphilic uniform penetration-resistant oil displacement agent includes the following steps:

[0094] (1) Add a certain amount of surfactant to the solvent and stir to form a uniform emulsion. Weigh appropriate amounts of sodium styrene sulfonate, acrylamide, N-(3-hydroxypropyl)-N-(3-methoxypropyl)acrylamide and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine according to the formula ratio, and dissolve them into the emulsion respectively. Then add the emulsion into the reactor.

[0095] (2) While stirring, dissolve the initiator in an appropriate amount of water, continuously introduce nitrogen or inert gas into the reactor for at least 30 minutes, heat to the reaction temperature and slowly add per-tert-butyl hydroperoxide and sodium bicarbonate dropwise into the reactor. After the reaction is completed, cool the solution, wash the product with a large amount of organic solvent and precipitate it, filter, take the precipitate, put it in a vacuum drying oven, dry it at a constant temperature of 50-70℃ for at least 24 hours, and then crush it with a crusher to obtain an amphiphilic uniform penetration inhibitor oil displacement agent.

[0096] Further, the surfactant mentioned in step (1) is one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, Tween-80, Tween-60, and Tween-90, wherein:

[0097] The amount of surfactant added in step (1) is 5%-10% of the sum of the masses of all monomers.

[0098] Furthermore, in step (2), the mass ratio of per-tert-butyl hydroperoxide to sodium chloroform is 1:2 to 5.

[0099] Further, the organic solvent mentioned in step (2) is one or more of acetone, ethanol, benzene, toluene, xylene, pentane, hexane, octane, chlorobenzene, dichlorobenzene, dichloromethane, cyclohexane, cyclohexanone, toluenecyclohexanone, methanol, isopropanol, and acetonitrile.

[0100] The amphiphilic uniform penetration inhibitor oil displacement agent is prepared by the above-described preparation method.

[0101] Application of amphiphilic uniform permeability-inhibiting oil displacement agents as chemical viscosity reducers in cold production of inefficient water-driven heavy oil reservoirs.

[0102] like Figure 1 As shown, the steps to improve the recovery rate are as follows:

[0103] (1) Screening of target inefficient water-driven heavy oil blocks;

[0104] (2) Inject the plugging agent;

[0105] (3) Continuously inject the above-mentioned amphiphilic uniform penetration inhibitory oil displacement agent;

[0106] (4) Continuous production after well opening.

[0107] Further, the screening criteria for the target block in step (1) are as follows: oil reservoir burial depth ≤1400m, total effective reservoir thickness 4~12m, reservoir clay content 8~15%, medium to weak water sensitivity, average porosity 15~40%, average permeability 50~400mD, permeability grade difference >3, remaining oil saturation 35~65%, underground crude oil viscosity 50~1000mPa·s, and average water cut of the block's oil wells above 95%.

[0108] Further, the specific steps of step (2) are as follows: the plugging agent is prepared into a plugging agent solution with a mass concentration of 10-12% using oilfield water at 40-50℃, and injected into the formation by forward extrusion at a rate of 5-10m³. 3 / h, replacing 20-30m of oilfield water 3 30-50m of water was displaced from the oilfield. 3 , well shut-in to diffuse pressure.

[0109] Further, the blockage agent mentioned in step (2) is composed of polyacrylamide dry powder, inorganic crosslinking agent, and organic crosslinking agent, wherein:

[0110] The molar ratio of polyacrylamide dry powder: inorganic crosslinking agent: organic crosslinking agent is 3-6:1:5-9.

[0111] Furthermore, the inorganic crosslinking agent is one of chromium-based inorganic crosslinking agents, aluminum-based inorganic crosslinking agents, and zirconium-based inorganic crosslinking agents, preferably a chromium-based inorganic crosslinking agent;

[0112] The organic crosslinking agent is a dicumyl peroxide crosslinking agent or a polycarbodiimide crosslinking agent, preferably a polycarbodiimide crosslinking agent;

[0113] The polyacrylamide powder is anionic polyacrylamide with a degree of hydrolysis of 1-6% and a molecular weight of 10 million-12 million.

[0114] Furthermore, the injection volume Q1 of the plugging agent is calculated according to the following formula:

[0115] Q1=π(R1 2 -r1 2 )×h1×φ1×α1×β1

[0116] Where: Q1 – injection volume of the plugging agent, m 3 ;

[0117] R1 – Radius of the blockage treatment agent, in meters;

[0118] r1—displacement radius, ranging from 0.3 to 0.5 m;

[0119] h1 — Total effective thickness of the treated oil layer, in meters;

[0120] φ1 – Average formation porosity, %;

[0121] α1 – Direction coefficient, dimensionless, ranging from 1.3 to 1.5;

[0122] β1 – dosage coefficient, dimensionless, ranging from 1.2 to 1.6.

[0123] A schematic diagram of the calculation model for the dosage of the blockage regulator Q1 is shown below. Figure 2 As shown.

[0124] Furthermore, the treatment radius R1 of the blockage modifier is related to the remaining oil saturation. The specific relationship is as follows: when the remaining oil saturation is greater than 50%, the treatment radius R1 of the blockage modifier is 3 to 5 m; when the remaining oil saturation is less than 50%, the treatment radius R1 of the blockage modifier is 5 to 7 m.

[0125] Further, in step (3), the specific steps for injecting the amphiphilic uniform permeability-restricting oil displacement agent are as follows: the above-mentioned amphiphilic uniform permeability-restricting oil displacement agent is prepared with oilfield water at 40-50℃ to form a viscosity-reducing solution with a mass concentration of 3-5%, and injected from the central well at a low discharge rate. The low discharge rate refers to an injection speed of less than 2m. 3 / h.

[0126] Furthermore, the injection amount Q2 of the amphiphilic uniform penetration-resistant oil displacement agent is calculated according to the following formula:

[0127] Q2=π(R2 2 -r2 2 )×h2×φ2×α2×β2

[0128] In the formula: Q2 – injection volume of amphiphilic uniform penetration inhibitor, m 3 ;

[0129] R2 – Treatment radius of the amphiphilic uniform penetration inhibitory oil displacement agent, in meters;

[0130] r2—displacement radius, ranging from 0.3m to 0.5m;

[0131] h2 — Processing layer thickness, m;

[0132] φ2 – Formation porosity, %;

[0133] α2 – Direction coefficient, dimensionless, ranging from 1.3 to 1.5;

[0134] β2 – dosage coefficient, dimensionless, with a value range of 8 to 10.

[0135] A schematic diagram of the calculation model for the injection volume Q2 of the amphiphilic uniform penetration resistance oil displacement agent is shown below. Figure 2 .

[0136] Furthermore, the treatment radius R2 of the amphiphilic uniform penetration resistance oil displacement agent is related to the residual oil saturation. The specific relationship is as follows: when the residual oil saturation is greater than 50%, the treatment radius R2 of the amphiphilic uniform penetration resistance oil displacement agent is 3 to 5 m; when the residual oil saturation is less than 50%, the treatment radius R2 of the amphiphilic uniform penetration resistance oil displacement agent is 5 to 7 m.

[0137] Further, in step (4), the specific steps of well opening production are as follows: viscosity reduction drive each effective downhole pump starts pumping production.

[0138] Furthermore, in step (4), production enhancement measures are adjusted according to the production dynamics of the affected oil well: when the water cut of the produced fluid in the oil well exceeds 85%, the oil well is controlled to maintain a high water cut by intermittent operation, with an intermittent operation frequency of 1 to 3 days.

[0139] In one embodiment

[0140] An amphiphilic uniformly penetrating oil displacement agent, wherein the amphiphilic uniformly penetrating oil displacement agent contains structural unit A, structural unit B, structural unit C and structural unit D, the structural formula of structural unit A is shown in formula (1), the structural formula of structural unit B is shown in formula (2), the structural formula of structural unit C is shown in formula (3), and the structural formula of structural unit D is shown in formula (4), wherein:

[0141] The molar ratio of structural unit A, structural unit B, structural unit C and structural unit D is 2000:2000:4000:6000;

[0142] a = 1;

[0143] b is 2;

[0144] c is 1;

[0145] The viscosity-average molecular weight of the amphiphilic homopermeability-inhibiting oil displacement agent is 35 million.

[0146]

[0147]

[0148] Furthermore, the general structural formula of the amphiphilic uniform penetration-resistant oil displacement agent is as follows:

[0149] in:

[0150] m is 2000;

[0151] n is 2000;

[0152] p is 4000;

[0153] q is 6000;

[0154] a = 1;

[0155] b is 2;

[0156] c is 1;

[0157] The viscosity-average molecular weight of the amphiphilic uniform permeation-resistant oil displacement agent is 35 million.

[0158] The preparation method of the above-mentioned amphiphilic uniform penetration-resistant oil displacement agent includes the following steps:

[0159] In the presence of an initiator and a solvent, sodium styrene sulfonate, acrylamide, N-ethoxymethyl-N-isobutoxymethylacrylamide, and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine are subjected to solution polymerization, wherein:

[0160] The molar ratio of sodium styrene sulfonate, acrylamide, N-ethoxymethyl-N-isobutoxymethacryloyl and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine (CAS No.: 123-83-1) is 1:0.01:0.01:0.01;

[0161] The solution polymerization reaction results in an amphiphilic uniform penetration resistance oil displacement agent with a viscosity-average molecular weight of 35 million.

[0162] In another embodiment, the molar ratio of the sodium styrene sulfonate, the acrylamide, N-(3-hydroxypropyl)-N-(3-methoxypropyl)acrylamide and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine is 1:5:20:20.

[0163] Furthermore, the initiator is benzoyl peroxide / sucrose, and / or

[0164] The amount of initiator used is 0.01 times the amount of acrylamide used;

[0165] The mass ratio of benzoyl peroxide to sucrose is 1:0.5.

[0166] In another embodiment, the mass ratio of benzoyl peroxide to sucrose is 1:0.8. In another embodiment, the mass ratio of benzoyl peroxide to sucrose is 1:0.6.

[0167] Further, the solvent is toluene, and / or

[0168] The amount of solvent used is 0.8 times the total mass of the monomers.

[0169] Furthermore, a surfactant, specifically an alkylphenol polyoxyethylene ether, is added during the reaction process, wherein:

[0170] The amount of surfactant added in step (1) is 5% of the sum of the masses of all monomers.

[0171] The preparation method of the above-mentioned amphiphilic uniform penetration-resistant oil displacement agent includes the following steps:

[0172] (1) Add a certain amount of surfactant to the solvent to form a uniform emulsion. Weigh appropriate amounts of sodium styrene sulfonate, acrylamide, N-(3-hydroxypropyl)-N-(3-methoxypropyl)acrylamide and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine according to the formula ratio, and dissolve them into the emulsion respectively. Then add the emulsion into the reactor.

[0173] (2) While stirring, the initiator was dissolved in an appropriate amount of water, and nitrogen gas was continuously introduced into the reactor for 30 minutes. The reactor was heated to the reaction temperature and tert-butyl hydroperoxide and sodium bicarbonate were slowly added dropwise to the reactor. After the reaction was completed, the solution was cooled, the product was washed with a large amount of organic solvent and precipitated, filtered, the precipitate was taken and placed in a vacuum drying oven, and dried at 50°C for 96 hours. Then it was crushed by a crusher to obtain an amphiphilic uniform penetration inhibitor oil displacement agent.

[0174] Further, the surfactant in step (1) is alkylphenol polyoxyethylene ether, and the amount of surfactant added in step (1) is 5% of the sum of the masses of all monomers.

[0175] Further, in step (2), the mass ratio of per-tert-butyl hydroperoxide to sodium chloroform is 1:2. In another embodiment, the mass ratio of per-tert-butyl hydroperoxide to sodium chloroform is 1:5. In yet another embodiment, the mass ratio of per-tert-butyl hydroperoxide to sodium chloroform is 1:4.

[0176] Furthermore, the organic solvent mentioned in step (2) is acetone.

[0177] The amphiphilic uniform penetration inhibitor oil displacement agent is prepared by the above-described preparation method.

[0178] Application of amphiphilic uniform permeability-inhibiting oil displacement agents as chemical viscosity reducers in cold production of inefficient water-driven heavy oil reservoirs.

[0179] like Figure 1 As shown, the steps to improve the recovery rate are as follows:

[0180] (1) Screening of target inefficient water-driven heavy oil blocks;

[0181] (2) Inject the plugging agent;

[0182] (3) Continuously inject the above-mentioned amphiphilic uniform penetration inhibitory oil displacement agent;

[0183] (4) Continuous production after well opening.

[0184] Further, the screening criteria for the target block in step (1) are as follows: oil reservoir burial depth ≤1400m, total effective reservoir thickness 4~12m, reservoir clay content 8~15%, medium to weak water sensitivity, average porosity 15~40%, average permeability 50~400mD, permeability grade difference >3, remaining oil saturation 35~65%, underground crude oil viscosity 50~1000mPa·s, and average water cut of the block's oil wells above 95%.

[0185] Further, the specific steps of step (2) are as follows: the plugging agent is prepared into a 10% mass concentration plugging agent solution using 40℃ oilfield water, and injected into the formation by forward extrusion at a displacement of 5m³.3 / h, replacing 20m of oilfield water 3 30m of water was replaced by oilfield water. 3 , well shut-in to diffuse pressure.

[0186] Further, the blockage agent mentioned in step (2) is composed of polyacrylamide dry powder, inorganic crosslinking agent, and organic crosslinking agent, wherein:

[0187] The molar ratio of polyacrylamide dry powder: inorganic crosslinking agent: organic crosslinking agent is 3:1:5.

[0188] Furthermore, the inorganic crosslinking agent is a chromium-based inorganic crosslinking agent;

[0189] The organic crosslinking agent is dicumyl peroxide crosslinking agent;

[0190] The polyacrylamide powder is anionic polyacrylamide with a degree of hydrolysis of 1% and a molecular weight of 10 million.

[0191] Furthermore, the injection volume Q1 of the plugging agent is calculated according to the following formula:

[0192] Q1=π(R1 2 -r1 2 )×h1×φ1×α1×β1

[0193] Where: Q1 – injection volume of the plugging agent, m 3 ;

[0194] R1 – Radius of the blockage treatment agent, in meters;

[0195] r1—displacement radius, ranging from 0.3 to 0.5 m;

[0196] h1 — Total effective thickness of the treated oil layer, in meters;

[0197] φ1 – Average formation porosity, %;

[0198] α1 – Direction coefficient, dimensionless, ranging from 1.3 to 1.5;

[0199] β1 – dosage coefficient, dimensionless, ranging from 1.2 to 1.6.

[0200] A schematic diagram of the calculation model for the dosage of the blockage regulator Q1 is shown below. Figure 2 As shown.

[0201] Furthermore, the treatment radius R1 of the blockage modifier is related to the remaining oil saturation. The specific relationship is as follows: when the remaining oil saturation is greater than 50%, the treatment radius R1 of the blockage modifier is 3 to 5 m; when the remaining oil saturation is less than 50%, the treatment radius R1 of the blockage modifier is 5 to 7 m.

[0202] Further, in step (3), the specific steps for injecting the amphiphilic uniform permeability-restricting oil displacement agent are as follows: the above-mentioned amphiphilic uniform permeability-restricting oil displacement agent is prepared into a viscosity-reducing solution with a mass concentration of 3% using oilfield water at 40℃, and injected from the central well at a low discharge rate, wherein the low discharge rate refers to an injection speed of less than 2m 3 / h.

[0203] Furthermore, the injection amount Q2 of the amphiphilic uniform penetration-resistant oil displacement agent is calculated according to the following formula:

[0204] Q2=π(R2 2 -r2 2 )×h2×φ2×α2×β2

[0205] In the formula: Q2 – injection volume of amphiphilic uniform penetration inhibitor, m 3 ;

[0206] R2 – Treatment radius of the amphiphilic uniform penetration inhibitory oil displacement agent, in meters;

[0207] r2—displacement radius, ranging from 0.3m to 0.5m;

[0208] h2 — Processing layer thickness, m;

[0209] φ2 – Formation porosity, %;

[0210] α2 – Direction coefficient, dimensionless, ranging from 1.3 to 1.5;

[0211] β2 – dosage coefficient, dimensionless, with a value range of 8 to 10.

[0212] A schematic diagram of the calculation model for the injection volume Q2 of the amphiphilic uniform penetration resistance oil displacement agent is shown below. Figure 2 .

[0213] Furthermore, the treatment radius R2 of the amphiphilic uniform penetration resistance oil displacement agent is related to the residual oil saturation. The specific relationship is as follows: when the residual oil saturation is greater than 50%, the treatment radius R2 of the amphiphilic uniform penetration resistance oil displacement agent is 3 to 5 m; when the residual oil saturation is less than 50%, the treatment radius R2 of the amphiphilic uniform penetration resistance oil displacement agent is 5 to 7 m.

[0214] Further, in step (4), the specific steps of well opening production are as follows: viscosity reduction drive each effective downhole pump starts pumping production.

[0215] Furthermore, in step (4), production enhancement measures are adjusted according to the production dynamics of the affected oil well: when the water content of the produced fluid in the oil well exceeds 85%, the oil well is controlled to maintain a high water content by intermittent operation, with an intermittent operation frequency of 1 day.

[0216] In another embodiment

[0217] An amphiphilic uniformly penetrating oil displacement agent, wherein the amphiphilic uniformly penetrating oil displacement agent contains structural unit A, structural unit B, structural unit C and structural unit D, the structural formula of structural unit A is shown in formula (1), the structural formula of structural unit B is shown in formula (2), the structural formula of structural unit C is shown in formula (3), and the structural formula of structural unit D is shown in formula (4), wherein:

[0218] The molar ratio of structural unit A, structural unit B, structural unit C and structural unit D is 20000:40000:60000:100000;

[0219] a is 4;

[0220] b is 7;

[0221] c is 15;

[0222] The viscosity-average molecular weight of the amphiphilic homopermeability-inhibiting oil displacement agent is 40 million.

[0223]

[0224] Furthermore, the general structural formula of the amphiphilic uniform penetration-resistant oil displacement agent is as follows:

[0225] in:

[0226] m is 20000;

[0227] n is 40000;

[0228] p is 60000;

[0229] q is 100000;

[0230] a is 4;

[0231] b is 7;

[0232] c is 15;

[0233] The viscosity-average molecular weight of the amphiphilic uniform permeation-resistant oil displacement agent is 40 million.

[0234] The preparation method of the above-mentioned amphiphilic uniform penetration-resistant oil displacement agent includes the following steps:

[0235] In the presence of an initiator and a solvent, sodium styrene sulfonate, acrylamide, N-ethoxymethyl-N-isobutoxymethylacrylamide, and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine are subjected to solution polymerization, wherein:

[0236] The molar ratio of sodium styrene sulfonate, acrylamide, N-ethoxymethyl-N-isobutoxymethacryloyl and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine (CAS No.: 123-83-1) is 1:25:50:50.

[0237] The solution polymerization reaction results in an amphiphilic uniform penetration-resistant oil displacement agent with a viscosity-average molecular weight of 40 million.

[0238] In another embodiment, the molar ratio of the sodium styrene sulfonate, the acrylamide, N-(3-hydroxypropyl)-N-(3-methoxypropyl)acrylamide and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine is 1:10:40:40.

[0239] Furthermore, the initiator is tert-butyl hydroperoxide / sodium hydroxide, and / or...

[0240] The amount of initiator used is 0.5% of the amount of acrylamide used;

[0241] The mass ratio of tert-butyl hydroperoxide to sodium chloroform is 1:2. In another embodiment, the mass ratio of tert-butyl hydroperoxide to sodium chloroform is 1:5. In yet another embodiment, the mass ratio of tert-butyl hydroperoxide to sodium chloroform is 1:3.

[0242] Further, the solvent is xylene, and / or

[0243] The amount of solvent used is 5 times the total mass of the monomers.

[0244] Furthermore, a surfactant, specifically a fatty alcohol polyoxyethylene ether, is added during the reaction process, wherein:

[0245] The amount of surfactant added in step (1) is 10% of the sum of the masses of all monomers.

[0246] The preparation method of the above-mentioned amphiphilic uniform penetration-resistant oil displacement agent includes the following steps:

[0247] (1) Add a certain amount of surfactant to the solvent to form a uniform emulsion. Weigh appropriate amounts of sodium styrene sulfonate, acrylamide, N-(3-hydroxypropyl)-N-(3-methoxypropyl)acrylamide and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine according to the formula ratio, and dissolve them into the emulsion respectively. Then add the emulsion into the reactor.

[0248] (2) While stirring, the initiator was dissolved in an appropriate amount of water, and argon gas was continuously introduced into the reactor for 110 min. The reactor was heated to the reaction temperature and tert-butyl hydroperoxide and sodium bicarbonate were slowly added dropwise to the reactor. After the reaction was completed, the solution was cooled, the product was washed with a large amount of organic solvent and precipitated, filtered, the precipitate was taken and placed in a vacuum drying oven. After drying at 70°C for 24 h, it was crushed by a crusher to obtain an amphiphilic uniform permeation-resistant oil displacement agent.

[0249] Further, the surfactant in step (1) is a fatty alcohol polyoxyethylene ether, and the amount of surfactant added is 10% of the sum of the masses of all monomers.

[0250] Furthermore, in step (2), the mass ratio of per-tert-butyl hydroperoxide to sodium chloroform is 1:5.

[0251] Further, the organic solvent mentioned in step (2) is ethanol.

[0252] The amphiphilic uniform penetration inhibitor oil displacement agent is prepared by the above-described preparation method.

[0253] Application of amphiphilic uniform permeability-inhibiting oil displacement agents as chemical viscosity reducers in cold production of inefficient water-driven heavy oil reservoirs.

[0254] like Figure 1 As shown, the steps to improve the recovery rate are as follows:

[0255] (1) Screening of target inefficient water-driven heavy oil blocks;

[0256] (2) Inject the plugging agent;

[0257] (3) Continuously inject the above-mentioned amphiphilic uniform penetration inhibitory oil displacement agent;

[0258] (4) Continuous production after well opening.

[0259] Further, the screening criteria for the target block in step (1) are as follows: oil reservoir burial depth ≤1400m, total effective reservoir thickness 4~12m, reservoir clay content 8~15%, medium to weak water sensitivity, average porosity 15~40%, average permeability 50~400mD, permeability grade difference >3, remaining oil saturation 35~65%, underground crude oil viscosity 50~1000mPa·s, and average water cut of the block's oil wells above 95%.

[0260] Further, the specific steps of step (2) are as follows: the plugging agent is prepared into a plugging agent solution with a mass concentration of 10-12% using oilfield water at 50℃, and injected into the formation by forward extrusion at a displacement of 10m³. 3 / h, replacing 30m of oilfield water 3 50m of water was replaced by oilfield water. 3 , well shut-in to diffuse pressure.

[0261] Further, the blockage agent mentioned in step (2) is composed of polyacrylamide dry powder, inorganic crosslinking agent, and organic crosslinking agent, wherein:

[0262] The molar ratio of polyacrylamide dry powder: inorganic crosslinking agent: organic crosslinking agent is 6:1:9.

[0263] Furthermore, the inorganic crosslinking agent is an aluminum-based inorganic crosslinking agent;

[0264] The organic crosslinking agent is a polycarbodiimide crosslinking agent;

[0265] The polyacrylamide powder is anionic polyacrylamide with a degree of hydrolysis of 6% and a molecular weight of 12 million.

[0266] Furthermore, the injection volume Q1 of the plugging agent is calculated according to the following formula:

[0267] Q1=π(R1 2 -r1 2 )×h1×φ1×α1×β1

[0268] Where: Q1 – injection volume of the plugging agent, m 3 ;

[0269] R1 – Radius of the blockage treatment agent, in meters;

[0270] r1—displacement radius, ranging from 0.3 to 0.5 m;

[0271] h1 — Total effective thickness of the treated oil layer, in meters;

[0272] φ1 – Average formation porosity, %;

[0273] α1 – Direction coefficient, dimensionless, ranging from 1.3 to 1.5;

[0274] β1 – dosage coefficient, dimensionless, ranging from 1.2 to 1.6.

[0275] A schematic diagram of the calculation model for the dosage of the blockage regulator Q1 is shown below. Figure 2 As shown.

[0276] Furthermore, the treatment radius R1 of the blockage modifier is related to the remaining oil saturation. The specific relationship is as follows: when the remaining oil saturation is greater than 50%, the treatment radius R1 of the blockage modifier is 3 to 5 m; when the remaining oil saturation is less than 50%, the treatment radius R1 of the blockage modifier is 5 to 7 m.

[0277] Further, in step (3), the specific steps for injecting the amphiphilic uniform permeability-reducing oil displacement agent are as follows: the above-mentioned amphiphilic uniform permeability-reducing oil displacement agent is prepared into a viscosity-reducing agent solution with a mass concentration of 5% using oilfield water at 50℃, and injected from the central well at a low discharge rate, wherein the low discharge rate refers to an injection speed of less than 2m 3 / h.

[0278] Furthermore, the injection amount Q2 of the amphiphilic uniform penetration-resistant oil displacement agent is calculated according to the following formula:

[0279] Q2=π(R2 2 -r2 2 )×h2×φ2×α2×β2

[0280] In the formula: Q2 – injection volume of amphiphilic uniform penetration inhibitor, m 3 ;

[0281] R2 – Treatment radius of the amphiphilic uniform penetration inhibitory oil displacement agent, in meters;

[0282] r2—displacement radius, ranging from 0.3m to 0.5m;

[0283] h2 — Processing layer thickness, m;

[0284] φ2 – Formation porosity, %;

[0285] α2 – Direction coefficient, dimensionless, ranging from 1.3 to 1.5;

[0286] β2 – dosage coefficient, dimensionless, with a value range of 8 to 10.

[0287] A schematic diagram of the calculation model for the injection volume Q2 of the amphiphilic uniform penetration resistance oil displacement agent is shown below. Figure 2 .

[0288] Furthermore, the treatment radius R2 of the amphiphilic uniform penetration resistance oil displacement agent is related to the residual oil saturation. The specific relationship is as follows: when the residual oil saturation is greater than 50%, the treatment radius R2 of the amphiphilic uniform penetration resistance oil displacement agent is 3 to 5 m; when the residual oil saturation is less than 50%, the treatment radius R2 of the amphiphilic uniform penetration resistance oil displacement agent is 5 to 7 m.

[0289] Further, in step (4), the specific steps of well opening production are as follows: viscosity reduction drive each effective downhole pump starts pumping production.

[0290] Furthermore, in step (4), production enhancement measures are adjusted according to the production dynamics of the affected oil well: when the water cut of the produced fluid in the oil well exceeds 85%, the oil well is controlled to maintain a high water cut by intermittent operation, with an intermittent operation frequency of 3 days.

[0291] In yet another embodiment

[0292] An amphiphilic uniformly penetrating oil displacement agent, wherein the amphiphilic uniformly penetrating oil displacement agent contains structural unit A, structural unit B, structural unit C and structural unit D, the structural formula of structural unit A is shown in formula (1), the structural formula of structural unit B is shown in formula (2), the structural formula of structural unit C is shown in formula (3), and the structural formula of structural unit D is shown in formula (4), wherein:

[0293] The molar ratio of structural unit A, structural unit B, structural unit C and structural unit D is 1500:40000:60000:80000;

[0294] a is 3;

[0295] b is 6;

[0296] c is 12;

[0297] The viscosity-average molecular weight of the amphiphilic homopermeability-inhibiting oil displacement agent is 39 million.

[0298]

[0299] Furthermore, the general structural formula of the amphiphilic uniform penetration-resistant oil displacement agent is as follows:

[0300] in:

[0301] m is 15000;

[0302] n is 40000;

[0303] p is 60000;

[0304] q is 80000;

[0305] a is 3;

[0306] b is 6;

[0307] c is 12;

[0308] The viscosity-average molecular weight of the amphiphilic uniform permeation inhibitor is 39 million.

[0309] Furthermore, a surfactant, specifically Tween-60, was added during the reaction process, wherein:

[0310] The amount of surfactant added in step (1) is 8% of the sum of the masses of all monomers.

[0311] In another embodiment, a surfactant, specifically Tween, is also added during the reaction, wherein:

[0312] The amount of surfactant added in step (1) is 5% of the sum of the masses of all monomers.

[0313] The preparation method of the above-mentioned amphiphilic uniform penetration-resistant oil displacement agent includes the following steps:

[0314] In the presence of an initiator and a solvent, sodium styrene sulfonate, acrylamide, N-ethoxymethyl-N-isobutoxymethylacrylamide, and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine are subjected to solution polymerization, wherein:

[0315] The molar ratio of sodium styrene sulfonate, acrylamide, N-ethoxymethyl-N-isobutoxymethacryloyl and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine (CAS No.: 123-83-1) is 1:10:20:20.

[0316] The solution polymerization reaction results in an amphiphilic uniform penetration resistance oil displacement agent with a viscosity-average molecular weight of 39 million.

[0317] In another embodiment, the molar ratio of the sodium styrene sulfonate, the acrylamide, N-(3-hydroxypropyl)-N-(3-methoxypropyl)acrylamide and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine is 1:6:25:25.

[0318] Furthermore, the initiator is benzoyl peroxide / N,N-dimethylaniline, and / or

[0319] The amount of initiator used is 0.2% of the amount of acrylamide used;

[0320] The mass ratio of benzoyl peroxide to N,N-dimethylaniline is 1:1; in another embodiment, the mass ratio of benzoyl peroxide to N,N-dimethylaniline is 1:4. In yet another embodiment, the mass ratio of benzoyl peroxide to N,N-dimethylaniline is 1:2.

[0321] Furthermore, the initiator is ammonium persulfate / sodium bisulfite;

[0322] The amount of initiator used is 0.1% of the amount of acrylamide used;

[0323] The mass ratio of ammonium persulfate to sodium bisulfite is 1:0.8. In another embodiment, the mass ratio of ammonium persulfate to sodium bisulfite is 1:1.2. In yet another embodiment, the mass ratio of ammonium persulfate to sodium bisulfite is 1:1.

[0324] Further, the solvent is ethyl acetate, and / or

[0325] The amount of solvent used is twice the total mass of the monomers.

[0326] Further, the solvent is a mixture of toluene, xylene, benzene, ethyl acetate, and butyl acetate in equal mass ratios, and / or

[0327] The amount of solvent used is 5 times the total mass of the monomers.

[0328] Further, the solvent is butyl acetate, and / or

[0329] The amount of solvent used is three times the total mass of the monomers.

[0330] Furthermore, a surfactant, specifically Tween-60, was added during the reaction process, wherein:

[0331] The amount of surfactant added in step (1) is 5% of the sum of the masses of all monomers.

[0332] In another embodiment, a surfactant, specifically Tween-90, is also added during the reaction, wherein:

[0333] The amount of surfactant added in step (1) is 5% of the sum of the masses of all monomers.

[0334] The preparation method of the above-mentioned amphiphilic uniform penetration-resistant oil displacement agent includes the following steps:

[0335] (1) Add a certain amount of surfactant to the solvent and stir to form a uniform emulsion. Weigh appropriate amounts of sodium styrene sulfonate, acrylamide, N-(3-hydroxypropyl)-N-(3-methoxypropyl)acrylamide and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine according to the formula ratio, and dissolve them into the emulsion respectively. Then add the emulsion into the reactor.

[0336] (2) While stirring, dissolve the initiator in an appropriate amount of water, continuously introduce nitrogen or inert gas into the reactor for 40 minutes, heat to the reaction temperature and slowly add per-tert-butyl hydroperoxide and sodium bicarbonate dropwise into the reactor. After the reaction is completed, cool the solution, wash the product with a large amount of organic solvent and precipitate it, filter, take the precipitate, put it in a vacuum drying oven, dry it at 60°C for 24 hours, and then crush it with a crusher to obtain an amphiphilic uniform penetration inhibitor oil displacement agent.

[0337] Further, the surfactant in step (1) is Tween-60, wherein:

[0338] The amount of surfactant added in step (1) is 5% of the sum of the masses of all monomers.

[0339] Further, the surfactant in step (1) is Tween-90, wherein:

[0340] The amount of surfactant added in step (1) is 10% of the sum of the masses of all monomers.

[0341] Furthermore, in step (2), the mass ratio of per-tert-butyl hydroperoxide to sodium chloroform is 1:3.

[0342] Further, the organic solvent in step (2) is toluene. In another embodiment, the organic solvent in step (2) is xylene. In another embodiment, the organic solvent in step (2) is pentane. In another embodiment, the organic solvent in step (2) is hexane. In another embodiment, the organic solvent in step (2) is octane. In another embodiment, the organic solvent in step (2) is chlorobenzene. In another embodiment, the organic solvent in step (2) is dichlorobenzene. In another embodiment, the organic solvent in step (2) is dichloromethane. In another embodiment, the organic solvent in step (2) is cyclohexane. In another embodiment, the organic solvent in step (2) is cyclohexanone. In another embodiment, the organic solvent in step (2) is toluenecyclohexanone. In another embodiment, the organic solvent in step (2) is methanol. In another embodiment, the organic solvent in step (2) is isopropanol. In another embodiment, the organic solvent in step (2) is acetonitrile. In another embodiment, the organic solvent in step (2) is a mixture of acetone, ethanol, benzene, toluene, xylene, pentane, hexane, octane, chlorobenzene, dichlorobenzene, dichloromethane, cyclohexane, cyclohexanone, toluenecyclohexanone, methanol, isopropanol, and acetonitrile in equal mass ratios.

[0343] The amphiphilic uniform penetration inhibitor oil displacement agent is prepared by the above-described preparation method.

[0344] Application of amphiphilic uniform permeability-inhibiting oil displacement agents as chemical viscosity reducers in cold production of inefficient water-driven heavy oil reservoirs.

[0345] like Figure 1 As shown, the steps to improve the recovery rate are as follows:

[0346] (1) Screening of target inefficient water-driven heavy oil blocks;

[0347] (2) Inject the plugging agent;

[0348] (3) Continuously inject the above-mentioned amphiphilic uniform penetration inhibitory oil displacement agent;

[0349] (4) Continuous production after well opening.

[0350] Further, the screening criteria for the target block in step (1) are as follows: oil reservoir burial depth ≤1400m, total effective reservoir thickness 4~12m, reservoir clay content 8~15%, medium to weak water sensitivity, average porosity 15~40%, average permeability 50~400mD, permeability grade difference >3, remaining oil saturation 35~65%, underground crude oil viscosity 50~1000mPa·s, and average water cut of the block's oil wells above 95%.

[0351] Further, the specific steps of step (2) are as follows: the plugging agent is prepared into a plugging agent solution with a mass concentration of 11% using oilfield water at 45℃, and injected into the formation by positive extrusion, with a discharge of 6m 3 / h, replacing 25m of water from the oilfield. 3 35m of water was replaced by oilfield water. 3 , well shut-in to diffuse pressure.

[0352] Further, the blockage agent mentioned in step (2) is composed of polyacrylamide dry powder, inorganic crosslinking agent, and organic crosslinking agent, wherein:

[0353] The molar ratio of polyacrylamide dry powder: inorganic crosslinking agent: organic crosslinking agent is 5:1:6.

[0354] Furthermore, the inorganic crosslinking agent is a chromium-based inorganic crosslinking agent;

[0355] The organic crosslinking agent is dicumyl peroxide crosslinking agent;

[0356] The polyacrylamide powder is anionic polyacrylamide with a degree of hydrolysis of 6% and a molecular weight of 12 million.

[0357] Furthermore, the injection volume Q1 of the plugging agent is calculated according to the following formula:

[0358] Q1=π(R1 2 -r1 2 )×h1×φ1×α1×β1

[0359] Where: Q1 – injection volume of the plugging agent, m 3 ;

[0360] R1 – Radius of the blockage treatment agent, in meters;

[0361] r1—displacement radius, ranging from 0.3 to 0.5 m;

[0362] h1 — Total effective thickness of the treated oil layer, in meters;

[0363] φ1 – Average formation porosity, %;

[0364] α1 – Direction coefficient, dimensionless, ranging from 1.3 to 1.5;

[0365] β1 – dosage coefficient, dimensionless, ranging from 1.2 to 1.6.

[0366] A schematic diagram of the calculation model for the dosage of the blockage regulator Q1 is shown below. Figure 2 As shown.

[0367] Furthermore, the treatment radius R1 of the blockage modifier is related to the remaining oil saturation. The specific relationship is as follows: when the remaining oil saturation is greater than 50%, the treatment radius R1 of the blockage modifier is 3 to 5 m; when the remaining oil saturation is less than 50%, the treatment radius R1 of the blockage modifier is 5 to 7 m.

[0368] Further, in step (3), the specific steps for injecting the amphiphilic uniform permeability-restricting oil displacement agent are as follows: the above-mentioned amphiphilic uniform permeability-restricting oil displacement agent is prepared with 45℃ oilfield water to form a viscosity-reducing agent solution with a mass concentration of 3-5%, and injected from the central well at a low discharge rate. The low discharge rate refers to an injection speed of less than 2m. 3 / h.

[0369] Furthermore, the injection amount Q2 of the amphiphilic uniform penetration-resistant oil displacement agent is calculated according to the following formula:

[0370] Q2=π(R2 2 -r2 2 )×h2×φ2×α2×β2

[0371] In the formula: Q2 – injection volume of amphiphilic uniform penetration inhibitor, m 3 ;

[0372] R2 – Treatment radius of the amphiphilic uniform penetration inhibitory oil displacement agent, in meters;

[0373] r2—displacement radius, ranging from 0.3m to 0.5m;

[0374] h2 — Processing layer thickness, m;

[0375] φ2 – Formation porosity, %;

[0376] α2 – Direction coefficient, dimensionless, ranging from 1.3 to 1.5;

[0377] β2 – dosage coefficient, dimensionless, with a value range of 8 to 10.

[0378] A schematic diagram of the calculation model for the injection volume Q2 of the amphiphilic uniform penetration resistance oil displacement agent is shown below. Figure 2 .

[0379] Furthermore, the treatment radius R2 of the amphiphilic uniform penetration resistance oil displacement agent is related to the residual oil saturation. The specific relationship is as follows: when the residual oil saturation is greater than 50%, the treatment radius R2 of the amphiphilic uniform penetration resistance oil displacement agent is 3 to 5 m; when the residual oil saturation is less than 50%, the treatment radius R2 of the amphiphilic uniform penetration resistance oil displacement agent is 5 to 7 m.

[0380] Further, in step (4), the specific steps of well opening production are as follows: viscosity reduction drive each effective downhole pump starts pumping production.

[0381] Furthermore, in step (4), production enhancement measures are adjusted according to the production dynamics of the affected oil well: when the water cut of the produced fluid in the oil well exceeds 85%, the oil well is controlled to maintain a high water cut by intermittent operation, with an intermittent operation frequency of 2 days.

[0382] In yet another embodiment

[0383] An amphiphilic uniformly penetrating oil displacement agent, wherein the amphiphilic uniformly penetrating oil displacement agent contains structural unit A, structural unit B, structural unit C and structural unit D, the structural formula of structural unit A is shown in formula (1), the structural formula of structural unit B is shown in formula (2), the structural formula of structural unit C is shown in formula (3), and the structural formula of structural unit D is shown in formula (4), wherein:

[0384] The molar ratio of structural unit A, structural unit B, structural unit C and structural unit D is 10000:20000:10000:10000;

[0385] a is 2;

[0386] b is 3;

[0387] c is 8;

[0388] The viscosity-average molecular weight of the amphiphilic homopermeability-inhibiting oil displacement agent is 36 million.

[0389]

[0390] Furthermore, the general structural formula of the amphiphilic uniform penetration-resistant oil displacement agent is as follows:

[0391] in:

[0392] m is 10000;

[0393] n is 20000;

[0394] p is 10000;

[0395] q is 10000;

[0396] a is 2;

[0397] b is 3;

[0398] c is 8;

[0399] The viscosity-average molecular weight of the amphiphilic uniform permeation inhibitor is 36 million.

[0400] Furthermore, a surfactant, specifically Tween-80, was added during the reaction process, wherein:

[0401] The amount of surfactant added in step (1) is 6% of the sum of the masses of all monomers.

[0402] The preparation method of the above-mentioned amphiphilic uniform penetration-resistant oil displacement agent includes the following steps:

[0403] In the presence of an initiator and a solvent, sodium styrene sulfonate, acrylamide, N-ethoxymethyl-N-isobutoxymethylacrylamide, and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine are subjected to solution polymerization, wherein:

[0404] The molar ratio of sodium styrene sulfonate, acrylamide, N-ethoxymethyl-N-isobutoxymethacryloyl and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine (CAS No.: 123-83-1) is 1:1:2:2.

[0405] The solution polymerization reaction results in an amphiphilic uniform penetration resistance oil displacement agent with a viscosity-average molecular weight of 36 million.

[0406] In another embodiment, the molar ratio of the sodium styrene sulfonate, the acrylamide, N-(3-hydroxypropyl)-N-(3-methoxypropyl)acrylamide and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine is 1:6:30:30.

[0407] Furthermore, the initiator is tert-butyl hydroperoxide / sodium metabisulfite, and / or

[0408] The amount of initiator used is 0.3% of the amount of acrylamide used;

[0409] The mass ratio of tert-butyl hydroperoxide to sodium metabisulfite is 1:0.5. In another embodiment, the mass ratio of tert-butyl hydroperoxide to sodium metabisulfite is 1:1.0. In yet another embodiment, the mass ratio of tert-butyl hydroperoxide to sodium metabisulfite is 1:0.8.

[0410] Further, the solvent is ethyl acetate, and / or

[0411] The amount of solvent used is twice the total mass of the monomers.

[0412] Furthermore, a surfactant, specifically Tween-80, was added during the reaction process, wherein:

[0413] The amount of surfactant added in step (1) is 6% of the sum of the masses of all monomers.

[0414] The preparation method of the above-mentioned amphiphilic uniform penetration-resistant oil displacement agent includes the following steps:

[0415] (1) Add a certain amount of surfactant to the solvent and stir to form a uniform emulsion. Weigh appropriate amounts of sodium styrene sulfonate, acrylamide, N-(3-hydroxypropyl)-N-(3-methoxypropyl)acrylamide and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine according to the formula ratio, and dissolve them into the emulsion respectively. Then add the emulsion into the reactor.

[0416] (2) While stirring, the initiator was dissolved in an appropriate amount of water, and nitrogen gas was continuously introduced into the reactor for 60 minutes. The reactor was heated to the reaction temperature and tert-butyl hydroperoxide and sodium bicarbonate were slowly added dropwise to the reactor. After the reaction was completed, the solution was cooled, the product was washed with a large amount of organic solvent and precipitated, filtered, the precipitate was taken and placed in a vacuum drying oven, and dried at 60°C for 36 hours. Then it was crushed by a crusher to obtain an amphiphilic uniform penetration inhibitor oil displacement agent.

[0417] Further, the surfactant in step (1) is Tween-80, wherein:

[0418] The amount of surfactant added in step (1) is 6% of the sum of the masses of all monomers.

[0419] Furthermore, in step (2), the mass ratio of per-tert-butyl hydroperoxide to sodium chloroform is 1:5.

[0420] Furthermore, the organic solvent mentioned in step (2) is benzene.

[0421] The amphiphilic uniform penetration inhibitor oil displacement agent is prepared by the above-described preparation method.

[0422] Application of amphiphilic uniform permeability-inhibiting oil displacement agents as chemical viscosity reducers in cold production of inefficient water-driven heavy oil reservoirs.

[0423] like Figure 1 As shown, the steps to improve the recovery rate are as follows:

[0424] (1) Screening of target inefficient water-driven heavy oil blocks;

[0425] (2) Inject the plugging agent;

[0426] (3) Continuously inject the above-mentioned amphiphilic uniform penetration inhibitory oil displacement agent;

[0427] (4) Continuous production after well opening.

[0428] Further, the screening criteria for the target block in step (1) are as follows: oil reservoir burial depth ≤1400m, total effective reservoir thickness 4~12m, reservoir clay content 8~15%, medium to weak water sensitivity, average porosity 15~40%, average permeability 50~400mD, permeability grade difference >3, remaining oil saturation 35~65%, underground crude oil viscosity 50~1000mPa·s, and average water cut of the block's oil wells above 95%.

[0429] Further, the specific steps of step (2) are as follows: the plugging agent is prepared into a plugging agent solution with a mass concentration of 11% using oilfield water at 45℃, and injected into the formation by positive extrusion at a displacement of 6m³. 3 / h, replacing 25m of water from the oilfield. 3 40m of water was replaced by oilfield water. 3 , well shut-in to diffuse pressure.

[0430] Further, the blockage agent mentioned in step (2) is composed of polyacrylamide dry powder, inorganic crosslinking agent, and organic crosslinking agent, wherein:

[0431] The molar ratio of polyacrylamide dry powder: inorganic crosslinking agent: organic crosslinking agent is 4:1:7.

[0432] Furthermore, the inorganic crosslinking agent is a zirconium-based inorganic crosslinking agent;

[0433] The organic crosslinking agent is a polycarbodiimide crosslinking agent;

[0434] The polyacrylamide powder is anionic polyacrylamide with a degree of hydrolysis of 3% and a molecular weight of 11 million.

[0435] Furthermore, the injection volume Q1 of the plugging agent is calculated according to the following formula:

[0436] Q1=π(R1 2 -r1 2 )×h1×φ1×α1×β1

[0437] Where: Q1 – injection volume of the plugging agent, m 3 ;

[0438] R1 – Radius of the blockage treatment agent, in meters;

[0439] r1—displacement radius, ranging from 0.3 to 0.5 m;

[0440] h1 — Total effective thickness of the treated oil layer, in meters;

[0441] φ1 – Average formation porosity, %;

[0442] α1 – Direction coefficient, dimensionless, ranging from 1.3 to 1.5;

[0443] β1 – dosage coefficient, dimensionless, ranging from 1.2 to 1.6.

[0444] A schematic diagram of the calculation model for the dosage of the blockage regulator Q1 is shown below. Figure 2 As shown.

[0445] Furthermore, the treatment radius R1 of the blockage modifier is related to the remaining oil saturation. The specific relationship is as follows: when the remaining oil saturation is greater than 50%, the treatment radius R1 of the blockage modifier is 3 to 5 m; when the remaining oil saturation is less than 50%, the treatment radius R1 of the blockage modifier is 5 to 7 m.

[0446] Further, in step (3), the specific steps for injecting the amphiphilic uniform permeability-restricting oil displacement agent are as follows: the above-mentioned amphiphilic uniform permeability-restricting oil displacement agent is prepared with oilfield water at 40-50℃ to form a viscosity-reducing solution with a mass concentration of 3-5%, and injected from the central well at a low discharge rate. The low discharge rate refers to an injection speed of less than 2m. 3 / h.

[0447] Furthermore, the injection amount Q2 of the amphiphilic uniform penetration-resistant oil displacement agent is calculated according to the following formula:

[0448] Q2=π(R2 2 -r2 2 )×h2×φ2×α2×β2

[0449] In the formula: Q2 – injection volume of amphiphilic uniform penetration inhibitor, m 3 ;

[0450] R2 – Treatment radius of the amphiphilic uniform penetration inhibitory oil displacement agent, in meters;

[0451] r2—displacement radius, ranging from 0.3m to 0.5m;

[0452] h2 — Processing layer thickness, m;

[0453] φ2 – Formation porosity, %;

[0454] α2 – Direction coefficient, dimensionless, ranging from 1.3 to 1.5;

[0455] β2 – dosage coefficient, dimensionless, with a value range of 8 to 10.

[0456] A schematic diagram of the calculation model for the injection volume Q2 of the amphiphilic uniform penetration resistance oil displacement agent is shown below. Figure 2 .

[0457] Furthermore, the treatment radius R2 of the amphiphilic uniform penetration resistance oil displacement agent is related to the residual oil saturation. The specific relationship is as follows: when the residual oil saturation is greater than 50%, the treatment radius R2 of the amphiphilic uniform penetration resistance oil displacement agent is 3 to 5 m; when the residual oil saturation is less than 50%, the treatment radius R2 of the amphiphilic uniform penetration resistance oil displacement agent is 5 to 7 m.

[0458] Further, in step (4), the specific steps of well opening production are as follows: viscosity reduction drive each effective downhole pump starts pumping production.

[0459] Furthermore, in step (4), production enhancement measures are adjusted according to the production dynamics of the affected oil well: when the water cut of the produced fluid in the oil well exceeds 85%, the oil well is controlled to maintain a high water cut by intermittent operation, with an intermittent operation frequency of 2 days.

[0460] Example 1

[0461] The preparation method of the amphiphilic uniform penetration-resistant oil displacement agent is as follows:

[0462] 1. Using xylene and water in a 1:2 ratio as a solvent, add 5% Tween-80 and stir to form a homogeneous emulsion. The amount of this emulsion is 0.8 times the total mass of the monomers. Weigh sodium styrene sulfonate, acrylamide, N-(3-hydroxypropyl)-N-(3-methoxypropyl)acrylamide and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine in a molar ratio of 1:0.01:0.01:0.01 and dissolve them in the emulsion.

[0463] 2. Turn on the mechanical stirrer. The initiator is a mixture of per-tert-butyl hydroperoxide and sodium metabisulfite (mass ratio 1:1) dissolved in water. The amount of initiator is 0.01% of the mass of acrylamide. After setting up the reaction apparatus, purge with nitrogen to remove oxygen for 30 minutes. Heat to the reaction temperature and slowly add the initiator dropwise. After the reaction is complete, cool the solution. Wash the product with a large amount of acetone and ethanol and precipitate it. Place it in a vacuum drying oven and dry at 50°C for 24 hours. Then crush it with a crusher to obtain an amphiphilic uniform penetration inhibitor oil displacement agent.

[0464] Example 2

[0465] The preparation method of the amphiphilic uniform penetration-resistant oil displacement agent is as follows:

[0466] 1. Using xylene and water in a 1:2 ratio as a solvent, add 5% Tween-80 and stir to form a homogeneous emulsion. The amount of this emulsion is 3 times the total mass of the monomers. Weigh sodium styrene sulfonate, acrylamide, N-(3-hydroxypropyl)-N-(3-methoxypropyl)acrylamide and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine in a molar ratio of 1:8:30:30 and dissolve them in the emulsion.

[0467] 2. Turn on the mechanical stirrer. The initiator is a mixture of per-tert-butyl hydroperoxide and sodium metabisulfite (mass ratio 1:1) dissolved in water. The amount of initiator is 0.3% of the mass of acrylamide. After setting up the reaction apparatus, purge with nitrogen to remove oxygen for 30 minutes. Heat to the reaction temperature and slowly add the initiator dropwise. After the reaction is complete, cool the solution. Wash the product with a large amount of acetone and ethanol and precipitate it. Place it in a vacuum drying oven and dry at 50°C for 24 hours. Then crush it with a crusher to obtain an amphiphilic uniform penetration inhibitor oil displacement agent.

[0468] Example 3

[0469] The preparation method of the amphiphilic uniform penetration-resistant oil displacement agent is as follows:

[0470] 1. Using xylene and water in a 1:2 ratio as a solvent, add 5% Tween-80 and stir to form a homogeneous emulsion. The amount of this emulsion is 5 times the total mass of the monomers. Weigh sodium styrene sulfonate, acrylamide, N-(3-hydroxypropyl)-N-(3-methoxypropyl)acrylamide and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine in a molar ratio of 1:25:50:50 and dissolve them in the emulsion.

[0471] 2. Turn on the mechanical stirrer. The initiator is a mixture of per-tert-butyl hydroperoxide and sodium metabisulfite (mass ratio 1:1) dissolved in water. The amount of initiator is 0.5% of the mass of acrylamide. After setting up the reaction apparatus, purge with nitrogen to remove oxygen for 30 minutes. Heat to the reaction temperature and slowly add the initiator dropwise. After the reaction is complete, cool the solution. Wash the product with a large amount of acetone and ethanol and precipitate it. Place it in a vacuum drying oven and dry at 50°C for 24 hours. Then crush it with a crusher to obtain an amphiphilic uniform penetration inhibitor oil displacement agent.

[0472] Example 4

[0473] The steps to improve the recovery rate are as follows:

[0474] A certain water-driven heavy oil reservoir has a burial depth of 1250m, a total effective reservoir thickness of 9m, a clay content of 10.4%, is weakly water-sensitive, has an average porosity of 28%, an average permeability of 320mD, strong reservoir heterogeneity with a permeability gradient of 5, a remaining oil saturation of 54%, and a subsurface crude oil viscosity of 580mPa·s. The average water cut of the wells in the block is 98%. The selected test well group is a one-injection-eight-production system. The wells in the block are arranged in a vertical and inclined layout with a row-shaped well pattern, which meets the screening criteria of this invention.

[0475] (1) Injecting the plugging agent

[0476] The plugging agent was prepared into a 10% (w / w) solution using 50°C hot oilfield water and injected into the formation at a rate of 6 m³ / h. 3 / h, replacing 20m of oilfield water3 30m of water was replaced by oilfield water. 3 The wellhead 3-day diffusion pressure. The plugging agent is a compound of anionic polyacrylamide polymer (1% hydrolysis, molecular weight 12 million), inorganic crosslinking agent (chromium-based), and organic crosslinking agent (polycarbodiimide-based), with a compounding ratio of polyacrylamide polymer: inorganic crosslinking agent: organic crosslinking agent = 3:1:6. The dosage of the plugging agent Q1 = 3.14 × (16 - 0.25) × 9 × 0.28 × 1.3 × 1.2 × 10% = 19.4 m³. 3 (R1=4m, r1=0.5m, α1=1.3, β1=1.2).

[0477] (2) Continuous injection of amphiphilic uniform penetration-resistant oil displacement agent:

[0478] An amphiphilic, homogeneous penetration-resistant oil displacement agent was prepared into a 5% (w / w) viscosity-reducing solution using oilfield water at 50°C. The solution was then applied at a depth of 1.5m... 3 The injection rate is / h from the central water well. The dosage of the amphiphilic, uniformly permeable oil displacement agent is Q2 = 3.14 × (25 - 0.25) × 9 × 0.28 × 1.3 × 8 × 5% = 101.8 m³. 3 (R2=5m, r2=0.5m, α2=1.3, β2=8).

[0479] (3) Using a continuous injection method, 8 effective wells were put into production. After field application, the water cut decreased by 11%, the average daily oil increase per well was 4.4 tons, and the input-output ratio was 1:5.

[0480] Example 5

[0481] The steps to improve the recovery rate are as follows:

[0482] A certain water-driven heavy oil reservoir has a burial depth of 1388m, a total effective reservoir thickness of 11.4m, a clay content of 9.2%, is weakly water-sensitive, has an average porosity of 33%, an average permeability of 337mD, strong reservoir heterogeneity with a permeability gradient of 7, a remaining oil saturation of 44%, and a subsurface crude oil viscosity of 757mPa·s. The average water cut of the wells in the block is 96%. The selected test well group is a two-injection, ten-production system. The wells in the block are arranged in a vertical and inclined layout with a row-shaped well pattern, which meets the screening criteria of this invention.

[0483] (1) Injecting the plugging agent:

[0484] The plugging agent was prepared into a 10% (w / w) solution using 50°C hot oilfield water and injected into the formation at a rate of 6 m³ / h. 3 / h, replacing 20m of oilfield water 3 30m of water was replaced by oilfield water. 3The wellhead diffusion pressure after 3 days is determined. The plugging agent is a compound of anionic polyacrylamide polymer (1% hydrolysis, molecular weight 12 million), inorganic crosslinking agent (chromium-based), and organic crosslinking agent (polycarbodiimide-based), with a compounding ratio of polyacrylamide polymer: inorganic crosslinking agent: organic crosslinking agent = 3:1:6. The dosage of the plugging agent Q1 = 3.14 × (36 - 0.25) × 11.4 × 0.33 × 1.5 × 1.6 × 10% = 101.4 m³. 3 (R1 = 6m, r1 = 0.5m,

[0485] α1 = 1.5, β1 = 1.6).

[0486] (2) Continuous injection of amphiphilic uniform penetration-resistant oil displacement agent:

[0487] An amphiphilic, homogeneous penetration-resistant oil displacement agent was prepared into a 4% (w / w) viscosity-reducing solution using oilfield water at 50°C. The solution was then applied at a depth of 1.5m... 3 The injection rate is / h from the central water well. The dosage of the amphiphilic, uniformly permeable oil displacement agent is Q2 = 3.14 × (36 - 0.25) × 11.4 × 0.33 × 1.5 × 10 × 4% = 253.4 m³. 3 (R2=6m, r2=0.5m, α2=1.5, β2=10).

[0488] (3) Using a continuous injection method, 10 effective wells were put into production. After field application, the water cut decreased by 10.6%, the average daily oil increase per well was 4.1 tons, and the input-output ratio was 1:6.

[0489] Performance Characterization

[0490] Test Experiment Example 1:

[0491] Infrared spectroscopy was performed on the amphiphilic homopermeability-inhibiting oil displacement agent prepared in Example 1, and the results are as follows: Figure 3 As shown. Figure 3 Middle, 1324cm -1 The peak at 1402 cm⁻¹ is a characteristic absorption peak of the NH bond in the amide group. -1 It is the antisymmetric stretching vibration peak of the branched-chain methoxy group; 1452 cm⁻¹ -1 and 1557cm -1 These are the stretching vibration peaks of C=O in hydroxypropyl and C=O in dimethylpropyl-1-amine, respectively; 1665 cm⁻¹ -1 It is the characteristic absorption peak of styrene in the structure, 3348 cm⁻¹ -1 It is the stretching vibration peak of CO.

[0492] Test Experiment Example 2

[0493] Referring to the industry standard "SY / T 6315-2017 Method for Determination of Relative Permeability and Oil Displacement Efficiency at High Temperature in Heavy Oil Reservoirs", the bureau standard "Q / SH 10202777-2020 General Technical Conditions for Thermal Recovery Plugging Agents", and the bureau standard "Q / SH 10201519-2016 General Technical Conditions for Heavy Oil Viscosity Reducers", the viscosity-reducing and dehydration performance, plugging rate, and displacement efficiency of the amphiphilic uniform permeability-blocking oil displacement agent JSZ-1 ​​prepared in Example 1 and the existing heavy oil viscosity-reducing oil displacement agent JNQY (a commercially available viscosity-reducing oil displacement agent product, obtained by compounding sodium dodecylbenzenesulfonate and ethoxylated alkyl sulfate) were evaluated.

[0494] 1. Experiment on viscosity reduction and dehydration effect

[0495] The experimental oil sample was degassed and dehydrated crude oil from an oilfield, with a viscosity of 12580 mPa·s after dehydration at 50℃. The invention sample and comparative sample were prepared as follows: Two 360g portions of the oil sample were weighed into beakers, and 40g of JSZ-1 ​​and JNQY reagent stock solutions were added to each beaker. The beakers were placed in a constant-temperature water bath at 50℃ and kept at that temperature for 1 hour. A stirring paddle was placed in the center of the beaker, 2–3 mm from the bottom, and the stirring speed was adjusted to 250 r / min. The mixture was stirred for 2 minutes under constant-temperature conditions. Within 20 seconds, the viscosity of the prepared heavy oil emulsion was rapidly measured using a rotational viscometer, and the viscosity reduction rate was calculated.

[0496] The viscosities before and after adding JSZ-1 ​​and JNQY were measured using a BROOKFIELD DVN viscometer. The experimental results are shown in Table 1.

[0497] Table 1 Evaluation of viscosity reduction effect

[0498]

[0499] As shown in Table 1, the amphiphilic uniform permeation barrier oil displacement agent JSZ-1 ​​of the present invention achieves a viscosity reduction rate of 99.0% for crude oil. The amphiphilic uniform permeation barrier oil displacement agent JSZ-1 ​​prepared in Example 1 has a better viscosity reduction effect than the existing viscosity-reducing oil displacement agent JNQY, and the dehydration meets the standard.

[0500] 2. Sealing performance test

[0501] Experimental conditions: Φ25×300mm core, sand-filled core tube, using 40-200 mesh quartz sand mixed evenly, dry filling method. Experimental temperature: 50℃.

[0502] JSZ-1 ​​system and JNQY system: 1% concentration was prepared using oilfield water (mineralization 4857.90 mg / L).

[0503] Experimental steps:

[0504] a. Inject water into the core at a flow rate of 0.5 mL / min and measure the permeability k of the core before plugging. 01 =1550mD、 k 02 =1602mD);

[0505] b. Inject 1.5PV of freshly prepared JSZ-1 ​​system solution and JNQY system solution respectively, and place the two cores in a 50℃ constant temperature oven for standing.

[0506] c. Re-inject water, monitor pressure changes during the injection process, and measure the post-plugging permeability (k) of the core. 11 and k 12 );

[0507] d. Calculate the core plugging rate according to the following formula:

[0508]

[0509] Table 2. Plugging rates of JSZ-1 ​​and JNQY

[0510] system Initial penetration rate, mD Post-plugging permeability, mD Blocking rate, % JSZ-1 1550 107.0 93.1 JNQY 1602 546.3 65.9

[0511] The plugging effect of the amphiphilic uniform permeability displacement agent system was determined by core displacement experiments. The experimental data showed that the JSZ-1 ​​system had a higher plugging strength than JNQY at 50℃.

[0512] 3. Displacement efficiency experiment

[0513] Experimental conditions: Experimental temperature 50℃, high and low permeability dual-pipe simulation of reservoir heterogeneity, crude oil viscosity of a certain well at 50℃ is 259mPa·s.

[0514] JSZ-1 ​​system and JNQY system: 1% concentration was prepared using oilfield water (mineralization 4857.90 mg / L).

[0515] Experimental steps:

[0516] a. Water drive 3PV + chemical agent 5PV + 3PV water drive.

[0517] b. After water flooding for 3 PV in both high- and low-permeability tubes, a two-tube experiment was conducted, followed by chemical flooding for 5 PV and water flooding for 3 PV. The injection pressure, injection volume, and product volume were recorded during the injection process.

[0518] Table 3. Core tubes used in the experiment and their parameters

[0519]

[0520]

[0521] Table 4 Summary of Displacement Efficiency of JSZ-1 ​​and JNQY

[0522]

[0523] like Figure 4 and Figure 5 As shown, the oil displacement effect of the amphiphilic uniform permeability-barrier oil displacement agent system was determined using core displacement experiments. For low-permeability pipes, the oil displacement efficiency of JSZ-1 ​​was 12.4% higher than that of JNQY, and the overall displacement efficiency was increased by 4.5%. JSZ-1 ​​can effectively utilize the remaining oil in low-permeability zones.

[0524] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. An amphiphilic uniform penetration inhibitor oil displacement agent, characterized in that, The amphiphilic uniform penetration-resistant oil displacement agent contains structural units A, B, C, and D. The structural formula of structural unit A is shown in formula (1), the structural formula of structural unit B is shown in formula (2), the structural formula of structural unit C is shown in formula (3), and the structural formula of structural unit D is shown in formula (4), wherein: The molar ratio of structural unit A, structural unit B, structural unit C and structural unit D is (2000~20000): (2000~40000): (4000~60000): (6000~100000); a is a positive integer from 1 to 4, preferably a positive integer from 2 to 3; b is a positive integer from 2 to 7, preferably a positive integer from 3 to 6; c is a positive integer from 1 to 15, preferably a positive integer from 8 to 12; The viscosity-average molecular weight of the amphiphilic homogeneous penetration inhibitor is 35 million to 40 million.

2. The amphiphilic uniform penetration inhibitor oil displacement agent as described in claim 1, characterized in that, The general structural formula of the amphiphilic uniform penetration-resistant oil displacement agent is as follows: in: m is a positive integer from 2000 to 20000, preferably a positive integer from 10000 to 15000; n is a positive integer from 2000 to 40000, preferably a positive integer from 20000 to 40000; p is a positive integer from 4000 to 60000, preferably a positive integer from 10000 to 60000; q is a positive integer from 6000 to 100000, preferably a positive integer from 10000 to 80000; a is a positive integer from 1 to 4, preferably a positive integer from 2 to 3; b is a positive integer from 2 to 7, preferably a positive integer from 3 to 6; c is a positive integer from 1 to 15, preferably a positive integer from 8 to 12; The viscosity-average molecular weight of the amphiphilic uniform permeation-resistant oil displacement agent is 35 million to 40 million.

3. The preparation method of the amphiphilic uniform penetration inhibitor oil displacement agent according to claim 1 or 2, characterized in that, The steps are as follows: In the presence of an initiator and a solvent, sodium styrene sulfonate, acrylamide, N-ethoxymethyl-N-isobutoxymethylacrylamide, and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine are subjected to solution polymerization, wherein: The molar ratio of sodium styrene sulfonate, acrylamide, N-ethoxymethyl-N-isobutoxymethacryloyl and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine is 1:0.01~25:0.01~50:0.01~50; The solution polymerization reaction results in an amphiphilic uniform permeation-resistant oil displacement agent with a viscosity-average molecular weight of 35 million to 40 million.

4. The preparation method of the amphiphilic uniform penetration inhibitor oil displacement agent as described in claim 3, characterized in that, The molar ratio of the sodium styrene sulfonate, the acrylamide, N-(3-hydroxypropyl)-N-(3-methoxypropyl)acrylamide, and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine is 1:5-10:20-40:20-40, and / or The initiator is one of the following: benzoyl peroxide / sucrose, tert-butyl hydroperoxide / sodium thiosulfate, tert-butyl hydroperoxide / sodium metabisulfite, benzoyl peroxide / N,N-dimethylaniline, ammonium persulfate / sodium bisulfite, and / or The amount of initiator used is 0.01-0.5% of the amount of acrylamide used; If the initiator is benzoyl peroxide / sucrose, the mass ratio of benzoyl peroxide to sucrose is 1:0.5 to 0.8; If the initiator is tert-butyl hydroperoxide / sodium benzoate, the mass ratio of tert-butyl hydroperoxide to sodium benzoate is 1:2 to 5. If the initiator is tert-butyl hydroperoxide / sodium metabisulfite, the mass ratio of tert-butyl hydroperoxide to sodium metabisulfite is 1:0.5 to 1.0; If the initiator is benzoyl peroxide / N,N-dimethylaniline, the mass ratio of benzoyl peroxide to N,N-dimethylaniline is 1:1 to 4; If the initiator is ammonium persulfate / sodium bisulfite, the mass ratio of ammonium persulfate to sodium bisulfite is 1:0.8 to 1.

2.

5. The preparation method of the amphiphilic uniform penetration inhibitor oil displacement agent as described in claim 3, characterized in that, The solvent is one or more of toluene, xylene, benzene, ethyl acetate, and butyl acetate, and / or The amount of solvent used is 0.8 to 5 times the total mass of the monomers, and / or A surfactant was also added during the reaction. The surfactant is one of the following: fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, Tween-80, Tween-60, and Tween-90. The amount of surfactant added in step (1) is 5%-10% of the sum of the masses of all monomers.

6. The method for preparing the amphiphilic uniform penetration inhibitor oil displacement agent according to claim 1 or 2, characterized in that, The steps are as follows: (1) Add a certain amount of surfactant to the solvent and stir to form a uniform emulsion. Weigh appropriate amounts of sodium styrene sulfonate, acrylamide, N-(3-hydroxypropyl)-N-(3-methoxypropyl)acrylamide and 3-acetamido-N-ethyl-N,N-dimethylpropyl-1-amine according to the formula ratio, and dissolve them into the emulsion respectively. Then add the emulsion into the reactor. (2) While stirring, dissolve the initiator in an appropriate amount of water, continuously introduce nitrogen or inert gas into the reactor for at least 30 minutes, heat to the reaction temperature and slowly add per-tert-butyl hydroperoxide and sodium bicarbonate dropwise into the reactor. After the reaction is completed, cool the solution, wash the product with a large amount of organic solvent and precipitate it, filter, take the precipitate, put it in a vacuum drying oven, dry it at a constant temperature of 50-70℃ for at least 24 hours, and then crush it with a crusher to obtain an amphiphilic uniform penetration inhibitor oil displacement agent.

7. The preparation method of the amphiphilic uniform penetration inhibitor oil displacement agent as described in claim 6, characterized in that, The surfactant mentioned in step (1) is one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, Tween-80, Tween-60, and Tween-90, wherein: The amount of surfactant added in step (1) is 5%-10% of the sum of the masses of all monomers, and / or In step (2), the mass ratio of per-tert-butyl hydroperoxide to sodium chloroform is 1:2-5, and / or The organic solvent mentioned in step (2) is one or more of the following: acetone, ethanol, benzene, toluene, xylene, pentane, hexane, octane, chlorobenzene, dichlorobenzene, dichloromethane, cyclohexane, cyclohexanone, toluenecyclohexanone, methanol, isopropanol, and acetonitrile.

8. An amphiphilic uniform penetration inhibitor oil displacement agent, characterized in that, Prepared by the preparation method according to any one of claims 3-7.

9. The application of the amphiphilic uniform permeability-inhibiting oil displacement agent as described in claim 1, 2, or 8 as a chemical viscosity-reducing oil displacement agent in the cold production of inefficient water-driven heavy oil reservoirs.

10. A method for improving the recovery rate, characterized in that, The steps are as follows: (1) Screening of target inefficient water-driven heavy oil blocks; (2) Inject the plugging agent; (3) Continuous injection of the amphiphilic uniform penetration-resistant oil displacement agent according to any one of claims 1-2 and 8; (4) Continuous production after well opening.

11. The method for improving oil recovery as described in claim 10, characterized in that, The screening criteria for the target block mentioned in step (1) are as follows: reservoir depth ≤ 1400m, total effective reservoir thickness 4-12m, reservoir clay content 8-15%, moderately weakly water-sensitive, average porosity 15-40%, average permeability 50-400mD, permeability gradient > 3, remaining oil saturation 35-65%, underground crude oil viscosity 50-1000mPa·s, average water cut of wells in the block above 95%, and / or The specific steps of step (2) are as follows: Prepare a plugging agent solution with oilfield water at 40-50℃ to a mass concentration of 10-12%, and inject it into the formation by forward extrusion at a rate of 5-10 m³ / h. 3 / h, replacing 20-30m of oilfield water 3 30-50m of water was displaced from the oilfield. 3 Well shut-in diffusion pressure, and / or The blockage agent mentioned in step (2) is composed of polyacrylamide dry powder, inorganic crosslinking agent, and organic crosslinking agent, wherein: The molar ratio of polyacrylamide dry powder: inorganic crosslinking agent: organic crosslinking agent is 3-6:1:5-9.

12. The method for improving oil recovery as described in claim 11, characterized in that, The inorganic crosslinking agent is one of chromium-based inorganic crosslinking agents, aluminum-based inorganic crosslinking agents, and zirconium-based inorganic crosslinking agents, preferably a chromium-based inorganic crosslinking agent; The organic crosslinking agent is a dicumyl peroxide crosslinking agent or a polycarbodiimide crosslinking agent, preferably a polycarbodiimide crosslinking agent; The polyacrylamide powder is anionic polyacrylamide with a degree of hydrolysis of 1-6% and a molecular weight of 10-12 million, and / or The injection volume Q1 of the plugging agent is calculated according to the following formula: Q1=π(R1 2 -r1 2 )×h1×φ1×α1×β1 Where: Q1 – injection volume of the plugging agent, m 3 ; R1 – Radius of the blockage treatment agent, in meters; r1—displacement radius, ranging from 0.3 to 0.5 m; h1 — Total effective thickness of the treated oil layer, in meters; φ1 – Average formation porosity, %; α1 – Direction coefficient, dimensionless, ranging from 1.3 to 1.5; β1 – dosage coefficient, dimensionless, ranging from 1.2 to 1.

6.

13. The method for improving oil recovery as described in claim 11, characterized in that, The treatment radius R1 of the plugging agent is related to the remaining oil saturation, specifically as follows: when the remaining oil saturation is greater than 50%, the treatment radius R1 is 3-5m; when the remaining oil saturation is less than 50%, the treatment radius R1 is 5-7m, and / or In step (3), the specific steps for injecting the amphiphilic uniform permeability-restricting oil displacement agent are as follows: the amphiphilic uniform permeability-restricting oil displacement agent is prepared with oilfield water at 40-50℃ to form a viscosity-reducing solution with a mass concentration of 3-5%, and injected from the central well at a low discharge rate. The low discharge rate refers to an injection speed of less than 2m. 3 / h, and / or The injection amount Q2 of the amphiphilic uniform penetration-resistant oil displacement agent is calculated according to the following formula: Q2=π(R2 2 -r2 2 ) × h2 × ϕ 2 × α 2 × β 2 In the formula: Q2 – injection volume of amphiphilic uniform penetration inhibitor, m 3 ; R2 – Treatment radius of the amphiphilic uniform penetration inhibitory oil displacement agent, in meters; r2—displacement radius, ranging from 0.3m to 0.5m; h2 — Processing layer thickness, m; φ2 – Formation porosity, %; α2 – Direction coefficient, dimensionless, ranging from 1.3 to 1.5; β2 – Dosage coefficient, dimensionless, ranging from 8 to 10, and / or The treatment radius R2 of the amphiphilic uniform penetration barrier oil displacement agent is related to the residual oil saturation. Specifically, when the residual oil saturation is greater than 50%, the treatment radius R2 is 3–5 m; when the residual oil saturation is less than 50%, the treatment radius R2 is 5–7 m, and / or In step (4), the specific steps of well opening and production are as follows: starting production from each effective downhole pump of viscosity-reducing drive, and / or In step (4), production enhancement measures are adjusted according to the production dynamics of the affected oil well: when the water cut of the produced fluid in the oil well exceeds 85%, the oil well is controlled to maintain a high water cut by intermittent operation, with an intermittent operation frequency of 1 to 3 days.

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