A shallow layer ordinary heavy oil reservoir cold heavy oil viscosity reduction oil displacement agent and a preparation method and application thereof

Abstract

The present application provides a kind of shallow layer ordinary heavy oil reservoir cold using heavy oil viscosity reduction oil displacement agent and its preparation method and application, belong to oil field chemical field.The heavy oil viscosity reduction oil displacement agent provided by the present application includes nano surfactant 16-18% by mass fraction, anionic surfactant 28-32%, Gemini surfactant 22-36%, solubilizer 10%, and the rest is water.The viscosity reduction oil displacement agent can be effectively applied to the shallow layer ordinary heavy oil reservoir cold mining viscosity reduction oil displacement in formation water salinity ≤100000 mg / L, wherein the calcium and magnesium ion concentration ≤2500 mg / L, formation temperature ≤35 DEG C, and its preparation process is simple, low in cost, green and environment-friendly.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of oil field chemistry, and particularly relates to a heavy oil viscosity-reducing oil displacement agent for cold production of shallow and thin layer ordinary heavy oil reservoirs, and a preparation method and application thereof. BACKGROUND

[0002] The basic characteristics of the basic geology of the shallow and thin layer heavy oil reservoir can be summarized as four words, namely, "shallow", "thin", "thick" and "scattered". Among them, "shallow" refers to the shallow burial depth of the oilfield; "thin" refers to the thin thickness of the oil layer in the oilfield, which makes it difficult to meet the requirements of thermal production and difficult to implement oilfield production activities; "thick" refers to the very high viscosity of the crude oil; and "scattered" refers to the scattered distribution of the oil layer in the reservoir, and the uneven oil-water boundary.

[0003] The cold production viscosity-reducing chemical flooding technology for ordinary heavy oil reservoirs is to inject a heavy oil viscosity-reducing oil washing agent solution into the formation, use the oil washing function of the oil washing agent to strip the crude oil on the formation sand, and reduce the viscosity of the crude oil, so as to facilitate the migration of the crude oil in the formation, thereby improving the oil recovery, and is an oil production technology with great development potential.

[0004] Since the shallow and thin layer heavy oil has a shallow burial depth, the formation temperature is relatively low, generally at 20-35℃, and the use temperature of the conventional cold production viscosity-reducing oil displacement agent is generally above 50℃, so it is difficult to achieve the expected effect at low temperature, and therefore, there is an urgent need to develop a viscosity-reducing oil displacement agent suitable for cold production of shallow and thin layer ordinary heavy oil reservoirs. SUMMARY

[0005] The present application provides a heavy oil viscosity-reducing oil displacement agent for cold production of shallow and thin layer ordinary heavy oil reservoirs, which can be effectively applied to the cold production viscosity-reducing oil of the shallow and thin layer ordinary heavy oil reservoir with a formation water salinity of ≤100000 mg / L, a calcium and magnesium ion concentration of ≤2500 mg / L, and a formation temperature of ≤35℃, and has a simple preparation process, low cost and green environmental protection.

[0006] In order to achieve the above purpose, the present application provides a heavy oil viscosity-reducing oil displacement agent for cold production of shallow and thin layer ordinary heavy oil reservoirs, which comprises, by mass percentage, 16-18% of a nano surfactant, 28-32% of an anionic surfactant, 22-36% of a Gemini surfactant, 10% of a solubilizing agent, and the rest is water.

[0007] As a preferred, the nano surfactant is a low interfacial tension nano active agent with a code of HA007, which is commercially available from Ningbo Fengcheng Nanometer Technology Co., Ltd., and has a particle size of ≤200 nm. The nano surfactant used has ultra-low interfacial activity at low temperature, good injectability, and the characteristics of temperature resistance and salt resistance.

[0008] As preferred, the anionic surfactant is selected from the fatty alcohol polyoxyethylene ether carboxylate with model number AEC-9Na commercially available from Zibo Yonghong New Material Co., Ltd., and has the structural formula as shown below:

[0009]

[0010] wherein R is C 12-14 Natural fatty alcohols.

[0011] As preferred, the Gemini surfactant is selected from the decyne glycol polyoxyethylene ether commercially available from Liaoning Kelong Fine Chemical Co., Ltd. The decyne glycol polyoxyethylene ether has a wide application in the daily chemical field, and can be used as a surfactant for detergents, shampoos, shower gels and the like, and has good cleaning and decontamination capacity. Meanwhile, it can also be used as an emulsifier, a stabilizer and a thickening agent. Through a large number of experimental researches, it is found that it can be used for oil field enhanced oil recovery.

[0012] As preferred, the solubilizing agent is at least one of ethanol and isopropyl alcohol, and the purpose is to increase the phase solubility of each component and improve the appearance of the product.

[0013] The present application provides a preparation method of the shallow and thin layer ordinary heavy oil reservoir cold using heavy oil viscosity reduction oil displacement agent according to any one of the above technical solutions, comprising the following steps:

[0014] The anionic surfactant is added into the reaction kettle, and then the solubilizing agent is added. After uniform stirring at a temperature of 30-40℃, water is added, and stirred for 30min. Finally, the Gemini surfactant and the nano surfactant are fully stirred and uniformly mixed to obtain the shallow and thin layer ordinary heavy oil reservoir cold using heavy oil viscosity reduction oil displacement agent.

[0015] The present application provides an application of the shallow and thin layer ordinary heavy oil reservoir cold using heavy oil viscosity reduction oil displacement agent in the shallow and thin layer ordinary heavy oil reservoir cold production viscosity reduction chemical flooding, according to any one of the above technical solutions.

[0016] As preferred, the concentration of the heavy oil viscosity reduction oil displacement agent is 0.3%.

[0017] As preferred, when it is compatible with the water phase with a mineralization degree of ≤100000mg / L and a calcium and magnesium ion concentration of ≤2500mg / L, the corresponding index test is carried out according to the method of Q / SH10202871-2021, the interfacial tension is ≤4.9x10 -3 mN / m, the viscosity reduction rate is ≥95.2%, the oil washing efficiency is ≥45.7%, the viscosity reduction rate after adsorption is ≥93.6%, and the interfacial tension after adsorption is ≤5.5x10 -3mN / m.

[0018] Compared with the prior art, the application has the advantages and positive effects that:

[0019] 1. The application provides a shallow and thin layer ordinary heavy oil reservoir cold using heavy oil viscosity reduction oil displacement agent, which is mainly composed of nano surfactant HA007, anionic surfactant fatty alcohol polyoxyethylene ether carboxylate AEC-9Na and Gemini surfactant decyne glycol polyoxyethylene ether. The three surfactants have certain emulsification viscosity reduction and oil washing effects on ordinary heavy oil at low temperature. The best compounding ratio is determined through a large number of experiments, so that the oil-water interfacial tension of heavy oil can be reduced to ultra-low, thereby meeting the technical requirements of the shallow and thin layer ordinary heavy oil reservoir cold displacement.

[0020] 2. The application provides a shallow and thin layer ordinary heavy oil reservoir cold using heavy oil viscosity reduction oil displacement agent, which is mainly applied to shallow and thin layer ordinary heavy oil reservoir cold production viscosity reduction chemical flooding, uses the oil washing function of the oil displacement agent to strip the crude oil on the formation sand, reduces the oil-water interfacial tension, increases the capillary number and reduces the viscosity of the crude oil, facilitates the migration of the crude oil in the formation, thereby improving the oil recovery rate, and is a shallow and thin layer heavy oil development technology with great development potential.

[0021] 3. The shallow and thin layer ordinary heavy oil reservoir cold using heavy oil viscosity reduction oil displacement agent provided by the application has good oil-water compatibility in the application field, does not produce precipitation and does not cause formation plugging, and the produced liquid is easy to demulsify.

[0022] 4. The shallow and thin layer ordinary heavy oil reservoir cold using heavy oil viscosity reduction oil displacement agent provided by the application has simple production process, raw materials are easy to purchase, and is harmless to the environment and personnel from production to use, and meets the green environmental protection requirements. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0024] The raw materials in the embodiments of the application are purchased through commercial channels. The low interfacial tension nano active agent with the code HA007 is purchased from Ningbo Fengcheng Nanometer Technology Co., Ltd., the fatty alcohol polyoxyethylene ether carboxylate with the model AEC-9Na is purchased from Zibo Yonghong New Material Co., Ltd., the Gemini surfactant decyne glycol polyoxyethylene ether is purchased from Liaoning Kelong Fine Chemical Co., Ltd., and the solubilizing agent is a commercially available product.

[0025] Example 1

[0026] 320kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na was added to the reaction kettle, then 100kg of ethanol was added, stirred uniformly at a temperature of 30-40℃, then 160kg of water was added, stirred for 30min, finally 260kg of decynediol polyoxyethylene ether and 160kg of low interfacial tension nano active agent HA007 were added and stirred uniformly, to obtain a thick layer of ordinary thick oil reservoir cold using thick oil viscosity reducing oil displacement agent.

[0027] Example 2

[0028] 310kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na was added to the reaction kettle, then 100kg of isopropyl alcohol was added, stirred uniformly at a temperature of 30-40℃, then 170kg of water was added, stirred for 30min, finally 250kg of decynediol polyoxyethylene ether and 170kg of low interfacial tension nano active agent HA007 were added and stirred uniformly, to obtain a thick layer of ordinary thick oil reservoir cold using thick oil viscosity reducing oil displacement agent.

[0029] Example 3

[0030] 300kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na was added to the reaction kettle, then 50kg of ethanol and 50kg of isopropyl alcohol were added, stirred uniformly at a temperature of 30-40℃, then 180kg of water was added, stirred for 30min, finally 240kg of decynediol polyoxyethylene ether and 180kg of low interfacial tension nano active agent HA007 were added and stirred uniformly, to obtain a thick layer of ordinary thick oil reservoir cold using thick oil viscosity reducing oil displacement agent.

[0031] Example 4

[0032] 290kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na was added to the reaction kettle, then 50kg of ethanol and 50kg of isopropyl alcohol were added, stirred uniformly at a temperature of 30-40℃, then 200kg of water was added, stirred for 30min, finally 230kg of decynediol polyoxyethylene ether and 180kg of low interfacial tension nano active agent HA007 were added and stirred uniformly, to obtain a thick layer of ordinary thick oil reservoir cold using thick oil viscosity reducing oil displacement agent.

[0033] Example 5

[0034] 280kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na was added to the reaction kettle, then 50kg of ethanol and 50kg of isopropyl alcohol were added, stirred uniformly at a temperature of 30-40℃, then 220kg of water was added, stirred for 30min, finally 220kg of decynediol polyoxyethylene ether and 180kg of low interfacial tension nano active agent HA007 were added and stirred uniformly, to obtain a thick layer of ordinary thick oil reservoir cold using thick oil viscosity reducing oil displacement agent.

[0035] The shallow layer ordinary heavy oil reservoir cold using heavy oil viscosity reduction oil displacement agent provided by the present application is determined based on a large number of experiments, and any change will cause the detection index to be unqualified.

[0036] Comparative Example 1

[0037] 100 kg of ethanol and 480 kg of water were added to a reaction kettle and stirred uniformly, then 260 kg of decyne glycol polyoxyethylene ether and 160 kg of low interfacial tension nano active agent HA007 were added and stirred uniformly, to obtain the shallow layer ordinary heavy oil reservoir cold using heavy oil viscosity reduction oil displacement agent.

[0038] Comparative Example 1 is the shallow layer ordinary heavy oil reservoir cold using heavy oil viscosity reduction oil displacement agent obtained by removing the fatty alcohol polyoxyethylene ether carboxylate AEC-9Na in the formula of Example 1, wherein the amount of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na is supplemented with water.

[0039] Comparative Example 2

[0040] 320 kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na was added to a reaction kettle, then 100 kg of ethanol was added, and stirred uniformly at a temperature of 30-40℃, then 420 kg of water was added and stirred for 30 min, and finally 160 kg of low interfacial tension nano active agent HA007 was added and stirred uniformly, to obtain the shallow layer ordinary heavy oil reservoir cold using heavy oil viscosity reduction oil displacement agent.

[0041] Comparative Example 2 is the shallow layer ordinary heavy oil reservoir cold using heavy oil viscosity reduction oil displacement agent obtained by removing the decyne glycol polyoxyethylene ether in the formula of Example 1, wherein the amount of decyne glycol polyoxyethylene ether is supplemented with water.

[0042] Comparative Example 3

[0043] 320 kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na was added to a reaction kettle, then 100 kg of ethanol was added, and stirred uniformly at a temperature of 30-40℃, then 320 kg of water was added and stirred for 30 min, and finally 260 kg of decyne glycol polyoxyethylene ether was added and stirred uniformly, to obtain the shallow layer ordinary heavy oil reservoir cold using heavy oil viscosity reduction oil displacement agent.

[0044] Comparative Example 3 is the shallow layer ordinary heavy oil reservoir cold using heavy oil viscosity reduction oil displacement agent obtained by removing the low interfacial tension nano active agent HA007 in the formula of Example 1, wherein the amount of low interfacial tension nano active agent HA007 is supplemented with water.

[0045] Comparative Example 4

[0046] 270 kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na was added into the reaction kettle, then 100 kg of ethanol was added, and after being stirred uniformly at a temperature of 30-40 °C, 210 kg of water was added, stirred for 30 min, and finally 260 kg of decynediol polyoxyethylene ether and 160 kg of low interfacial tension nano active agent HA007 were added and stirred uniformly to obtain a cold heavy oil viscosity reducing and oil displacement agent for shallow and thin heavy oil reservoirs.

[0047] Comparative Example 4 was a cold heavy oil viscosity reducing and oil displacement agent for shallow and thin heavy oil reservoirs obtained by adding 270 kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na, which deviated from the range of 28%-32% of the amount of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na in the formula of Example 1.

[0048] Comparative Example 4 was a cold heavy oil viscosity reducing and oil displacement agent for shallow and thin heavy oil reservoirs obtained by adding 270 kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na, which deviated from the range of 28%-32% of the amount of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na in the formula of Example 1.

[0049] Comparative Example 5

[0050] 330 kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na was added into the reaction kettle, then 100 kg of ethanol was added, and after being stirred uniformly at a temperature of 30-40 °C, 150 kg of water was added, stirred for 30 min, and finally 260 kg of decynediol polyoxyethylene ether and 160 kg of low interfacial tension nano active agent HA007 were added and stirred uniformly to obtain a cold heavy oil viscosity reducing and oil displacement agent for shallow and thin heavy oil reservoirs.

[0051] Comparative Example 5 was a cold heavy oil viscosity reducing and oil displacement agent for shallow and thin heavy oil reservoirs obtained by adding 330 kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na, which deviated from the range of 28%-32% of the amount of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na in the formula of Example 1.

[0052] Comparative Example 5 was a cold heavy oil viscosity reducing and oil displacement agent for shallow and thin heavy oil reservoirs obtained by adding 330 kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na, which deviated from the range of 28%-32% of the amount of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na in the formula of Example 1.

[0053] Comparative Example 6

[0054] 320 kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na was added into the reaction kettle, then 100 kg of ethanol was added, and after being stirred uniformly at a temperature of 30-40 °C, 210 kg of water was added, stirred for 30 min, and finally 210 kg of decynediol polyoxyethylene ether and 160 kg of low interfacial tension nano active agent HA007 were added and stirred uniformly to obtain a cold heavy oil viscosity reducing and oil displacement agent for shallow and thin heavy oil reservoirs.

[0055] Comparative Example 6 is a deviation of 22%-26% from the amount of decynediol polyoxyethylene ether in the formulation of Example 1, i.e. 210 kg of decynediol polyoxyethylene ether (21%) is added to obtain the heavy oil viscosity reducing and oil displacement agent for shallow and thin heavy oil reservoirs, and the amount of less decynediol polyoxyethylene ether is supplemented with water.

[0056] Comparative Example 7

[0057] 320 kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na is added to the reaction kettle, then 100 kg of ethanol is added, stirred uniformly at a temperature of 30-40°C, then 150 kg of water is added, stirred for 30 min, finally 270 kg of decynediol polyoxyethylene ether and 160 kg of low interfacial tension nano active agent HA007 are fully stirred and uniformly mixed to obtain the heavy oil viscosity reducing and oil displacement agent for shallow and thin heavy oil reservoirs.

[0058] Comparative Example 7 is a deviation of 22%-26% from the amount of decynediol polyoxyethylene ether in the formulation of Example 1, i.e. 270 kg of decynediol polyoxyethylene ether (27%) is added to obtain the heavy oil viscosity reducing and oil displacement agent for shallow and thin heavy oil reservoirs, and the amount of more decynediol polyoxyethylene ether is removed from the amount in water.

[0059] Comparative Example 8

[0060] 320 kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na is added to the reaction kettle, then 100 kg of ethanol is added, stirred uniformly at a temperature of 30-40°C, then 170 kg of water is added, stirred for 30 min, finally 260 kg of decynediol polyoxyethylene ether and 150 kg of low interfacial tension nano active agent HA007 are fully stirred and uniformly mixed to obtain the heavy oil viscosity reducing and oil displacement agent for shallow and thin heavy oil reservoirs.

[0061] Comparative Example 8 is a deviation of 16%-18% from the amount of low interfacial tension nano active agent HA007 in the formulation of Example 1, i.e. 150 kg of low interfacial tension nano active agent HA007 (15%) is added to obtain the heavy oil viscosity reducing and oil displacement agent for shallow and thin heavy oil reservoirs, and the amount of less low interfacial tension nano active agent HA007 is supplemented with water.

[0062] Comparative Example 9

[0063] 320 kg of fatty alcohol polyoxyethylene ether carboxylate AEC-9Na is added to the reaction kettle, then 100 kg of ethanol is added, stirred uniformly at a temperature of 30-40°C, then 130 kg of water is added, stirred for 30 min, finally 260 kg of decynediol polyoxyethylene ether and 190 kg of low interfacial tension nano active agent HA007 are fully stirred and uniformly mixed to obtain the heavy oil viscosity reducing and oil displacement agent for shallow and thin heavy oil reservoirs.

[0064] Comparative Example 9 deviates from the range of 16%-18% of the amount of low interfacial tension nano-active agent HA007 in the formulation of Example 1, i.e. 190 kg of low interfacial tension nano-active agent HA007 (19%) is added to obtain a light thin layer of ordinary heavy oil reservoir cold heavy oil viscosity reduction oil displacement agent, and the amount of additional low interfacial tension nano-active agent HA007 is removed from the amount in water.

[0065] Comparative Example 10

[0066] The heavy oil viscosity reduction oil displacement agent sample applied to the Dongsheng Jin 8 block site has a formation temperature of 50°C (the lowest temperature sample currently applied to the site block).

[0067] Comparative Example 11

[0068] The heavy oil viscosity reduction oil displacement agent sample applied to the north site of the Gudao East area has a formation temperature of 70°C.

[0069] Performance test:

[0070] The products prepared in the above examples and comparative examples were mixed into a 0.3% concentration sample solution for performance testing. The test conditions and test methods refer to Q / SH1020 2871-2021 as follows:

[0071] Test conditions:

[0072] 1. Test instrument: Bohui DV3T rheometer, TX-500C full-range rotary drop interfacial tension meter, constant temperature water bath.

[0073] 2. Test temperature: formation temperature of a block in Henan Oilfield, 20°C.

[0074] 3. Test crude oil: dewatered crude oil from a block in Henan Oilfield (20°C viscosity 1346 mpa.s).

[0075] 4. Test water: injection water from a block in Henan Oilfield, salinity 100000 mg / L, calcium and magnesium ion concentration 2500 mg / L.

[0076] Test method:

[0077] 1. Interfacial tension test:

[0078] According to the provisions of 7.4 in Q / SH1020 2871-2021, the interfacial tension between the sample solution and the target block oil sample was determined at 20°C (rotation speed 5000 r / min, density difference calculated as 0.05), and the minimum interfacial tension was recorded.

[0079] 2. Viscosity reduction rate determination:

[0080] A solution with a mass concentration of 0.3% is prepared by using the injection water of a block in Shengli Oilfield to cool the shallow layer of ordinary heavy oil reservoirs with a heavy oil viscosity reducing oil displacement agent. 30g of the prepared sample solution is placed in a small beaker, 70g of an oil sample from a block in Henan Oilfield is added, and it is sealed and placed in a 20°C constant temperature laboratory for 2h. The oil-water mixture is taken out, stirred quickly with a glass rod to make the oil and water mix evenly, and the viscosity of the oil-water mixture at 20°C is quickly determined by a rheometer according to the provisions of Q / SH10202871-2021 7.5.

[0081] The viscosity reduction rate calculation formula is as follows:

[0082]

[0083] In the formula: f is the viscosity reduction rate;

[0084] μ0 is the viscosity of the heavy oil sample at 20°C, mPa·s;

[0085] μ is the viscosity of the oil-water mixture at 20°C, mPa·s.

[0086] 3, performance determination after adsorption

[0087] 30.0g of simulated formation sand is weighed into a screw cap reagent bottle, 90.0g of sample solution with a mass concentration of 0.3% is added, the cap is tightened, it is shaken evenly by hand, and it is placed in a constant temperature water bath shaker, the shaking frequency is set to 170r / min, and it is shaken for 24h in a 20°C constant temperature laboratory.

[0088] 3.1 determination of viscosity reduction rate after adsorption

[0089] The sample is taken out, and after standing for 60min, 30.0g of the supernatant is taken with a syringe and placed in a 250mL beaker, 70.0g of the experimental oil sample is added, it is sealed and placed in a 20°C constant temperature laboratory for 2h. The viscosity of the oil-water mixture at the oil reservoir temperature of 20°C is determined according to the provisions of Q / SH10202871-2021 7.5, and the viscosity reduction rate after adsorption is calculated.

[0090] 3.2 determination of interfacial tension after adsorption

[0091] According to the provisions of Q / SH1020 2871-2021 7.4, the interfacial tension between the supernatant after adsorption and the oil sample from the target block is measured at 20°C (rotation speed 5000r / min, density difference calculated as 0.05), and the minimum interfacial tension is recorded.

[0092] 4, oil washing rate determination:

[0093] 4.1 The simulated formation sand and the crude oil from the target block are mixed in a ratio of 4:1 (mass ratio) and placed in a 20°C constant temperature laboratory for aging for 7d, and stirred once a day to make the oil sand mixture uniform.

[0094] 4.2 Prepare 0.3% of the sample solution of the heavy oil viscosity-reducing oil displacement agent for shallow and thin general heavy oil reservoirs with the target block injection water, 100 g, and stir at a speed of 300 r / min on a magnetic stirrer for 15 min before testing.

[0095] 4.3 Put about 5 g of the aged oil sand into a 100 mL conical flask, weigh m1, and record to 0.001 g.

[0096] 4.4 Add 50 g of the prepared sample solution to the sample in 4.3, mix well, and stand for 48 h in a constant-temperature laboratory at 20℃.

[0097] 4.5 Dip the oil floating in the sample after standing in 4.4 and the oil adhering to the wall of the conical flask with clean cotton yarn, pour out the sample solution, and place the conical flask in an oven at 105℃ until it reaches a constant weight, and obtain m2.

[0098] 4.6 Elute the oil in the sample in 4.5 with petroleum ether until the petroleum ether is colorless. Place the conical flask in which the oil is eluted in an oven at 120℃ until it reaches a constant weight, and weigh m3.

[0099] 4.7 Calculate the oil washing rate according to the following formula:

[0100]

[0101] In the formula: σ—oil washing rate;

[0102] m1—total mass of the conical flask and oil sand before oil washing, g;

[0103] m2—mass of the conical flask and oil sand after oil washing, g;

[0104] m3—total mass of the conical flask and the cleaned formation sand, g.

[0105] The heavy oil viscosity-reducing oil displacement agent for shallow and thin general heavy oil reservoirs obtained in the above Examples 1-5 and Comparative Examples 1-9 is tested according to the above test methods for interfacial tension, viscosity reduction rate, oil washing efficiency, and interfacial tension and viscosity reduction rate after adsorption, and the test results are shown in Table 1. Among them, at 20℃, the standards of the following parameters according to Q / SH10202871-2021 are: interfacial tension ≤5.0×10 -2 mN / m, viscosity reduction rate ≥90%, oil washing efficiency ≥40%, viscosity reduction rate after adsorption ≥80%, and interfacial tension after adsorption ≤9.9×10 -2 mN / m.

[0106] Table 1 Performance test of heavy oil viscosity-reducing oil displacement agent for shallow and thin general heavy oil reservoirs

[0107]

[0108]

[0109] From the above Table 1, it can be seen that the formula provided by the present application can make the obtained light thin layer ordinary heavy oil reservoir cold heavy oil viscosity reduction oil displacement agent have more excellent performance than the parameter standard under the synergistic effect of low interfacial tension nano-active agent HA007, fatty alcohol polyoxyethylene ether carboxylate AEC-9Na and Gemini surfactant decynediol polyoxyethylene ether and the component proportion thereof, that is, ultra-low interfacial tension ≤ 4.9 x 10 -3 mN / m, viscosity reduction rate ≥ 95.2%, oil washing efficiency ≥ 45.7%, adsorption viscosity reduction rate ≥ 93.6%, adsorption interfacial tension ≤ 5.5 x 10 -3 mN / m and other characteristics, which means that it has strong oil displacement capacity, especially for shallow thin layer ordinary heavy oil reservoir, and can greatly improve the recovery rate of crude oil when applied in shallow thin layer ordinary heavy oil cold production viscosity reduction chemical flooding.

Claims

1. A cold heavy oil production with viscous oil (CHOPV) viscosity-reducing oil-displacing agent for shallow and thin-layer general heavy oil reservoirs, characterized in that, The nano surfactant is a low interfacial tension nano active agent with a particle size of less than or equal to 200 nm, which is commercially available from Ningbo Fengcheng Nanometer Technology Co., Ltd. and is denoted as HA007 in terms of mass percentage; The anionic surfactant is a fatty alcohol polyoxyethylene ether carboxylate with a model number of AEC-9Na and has a structural formula as shown in the following formula: The Gemini surfactant is decynediol polyoxyethylene ether; wherein R is C 12-14 natural fatty alcohols; The thickened oil viscosity-reducing oil displacement agent for shallow and thin layer ordinary heavy oil reservoir cold production can be effectively applied to shallow and thin layer ordinary heavy oil reservoir cold production viscosity reduction and oil displacement in which the formation water salinity is less than or equal to 100000 mg / L, the calcium and magnesium ion concentration is less than or equal to 2500 mg / L, and the formation temperature is less than or equal to 35 DEG C. The solubilizing agent is at least one of ethanol and isopropyl alcohol.

2. The heavy oil viscosity reduction and displacement agent according to claim 1, characterized in that, The method comprises the following steps:

3. The method according to any one of claims 1-2, characterized in that, The anionic surfactant is added into a reaction kettle, and then the solubilizing agent is added. After being uniformly stirred at a temperature of 30-40 DEG C, water is added, and then stirred for 30-45 min. Finally, the Gemini surfactant and the nano surfactant are added and uniformly stirred to obtain the thickened oil viscosity-reducing oil displacement agent for shallow and thin layer ordinary heavy oil reservoir cold production.

4. The application of the thickened oil viscosity-reducing oil displacement agent for shallow and thin layer ordinary heavy oil reservoir cold production according to any one of claims 1-2 in shallow and thin layer ordinary heavy oil reservoir cold production viscosity reduction and oil displacement in which the formation water salinity is less than or equal to 100000 mg / L, the calcium and magnesium ion concentration is less than or equal to 2500 mg / L, and the formation temperature is less than or equal to 35 DEG C. The thickened oil viscosity-reducing oil displacement agent is used at a concentration of 0.3%.

5. Use according to claim 4, characterized in that, ​ 6. Use according to claim 4, characterized in that, When it is matched with a water phase with a mineralization of ≤100000 mg / L, wherein the concentration of calcium and magnesium ions is ≤2500 mg / L, the interfacial tension thereof is ≤4.9*10 -3 mN / m, the viscosity reduction rate is ≥95.2%, the oil washing efficiency is ≥45.7%, the viscosity reduction rate after adsorption is ≥93.6%, and the interfacial tension after adsorption is ≤5.5*10 -3 mN / m.

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