Adhesive stock solution suitable for polymer preparation of oilfield produced water as well as preparation method and application of adhesive stock solution

Abstract

The invention relates to a viscosity-retaining agent stock solution suitable for oilfield produced water polymer preparation and a preparation method and application thereof. The invention relates to a viscosity-keeping agent stock solution suitable for oilfield produced water polymer preparation. The viscosity-keeping agent stock solution comprises the following components: 15-30% of a zwitterionic surfactant; 10-15% of an organic solvent; 5-15% of water; 0.1 to 0.3 percent of nitrite; and the balance of a nonionic surfactant. The preparation method comprises the following steps: (1) adding a nonionic surfactant, a zwitterionic surfactant and an organic solvent into a reaction container according to a formula ratio, and stirring to obtain a mixed solution; (2) adding 50%-70% of water in the formula amount into a reaction container, stirring, adding the rest of water and nitrite in the formula amount, and uniformly stirring to obtain a stock solution of the viscosity-keeping agent; the invention relates to the application of the viscosity-retaining agent stock solution suitable for oil field produced water polymer preparation in oil exploitation. According to the invention, the injection allocation viscosity of the chemical flooding polymer can be greatly improved, and the stratum sweep capacity and the oil displacement effect of a chemical oil displacement system are guaranteed.

Description

Technical Field

[0001] The invention belongs to the field of petroleum engineering, relates to oilfield polymerization water treatment and polymer high-efficiency viscosity preservation technology, and specifically relates to a viscosity preservation agent stock solution suitable for oilfield produced water polymerization and a preparation method and application thereof. Background Art

[0002] In the field of oil and gas field development, chemical flooding is an important means to improve the recovery rate of old oil fields with extremely high water content.

[0003] At present, chemical flooding technology has been applied on a large scale in oil fields such as Daqing, Shengli, Dagang, Liaohe, and Xinjiang, with significant effects of reducing water and increasing oil production in mines and economic benefits. For example, Chinese invention patent application CN 113214815A (the applicant is Daqing Yongzhu Petroleum Technology Development Co., Ltd.) discloses a nano-microemulsion oil-displacing agent, which is composed of water, oil, surfactant, isopropanol and sodium chloride; wherein the volume ratio of oil to water is 0.8 to 0.9:1, and the concentration of surfactant is 2.0 to 2.5wt% based on the total weight of oil and water, the concentration of isopropanol is 3.0 to 8.0wt%, and the concentration of sodium chloride is 2.0 to 5.5wt%; the surfactant is a combination of polyoxyethylene ether nonionic surfactant (Triton X) and sulfonated saponin. The nano-microemulsion oil-displacing agent of the present invention belongs to a medium-phase microemulsion, with a small particle size and a droplet size of about 20 to 50nm, and the interfacial tension with both oil and water phases can be reduced to 1.0×10 -4 mN / m or less, and can increase the crude oil recovery rate by at least 10 percentage points compared with water flooding. Chinese invention patent application CN1865392A (the applicant is the Institute of Geological Sciences of Shengli Oilfield Branch of Sinopec) discloses a high-efficiency compound oil-displacing agent used in tertiary oil recovery and its preparation method. The oil-displacing agent is prepared by compounding petroleum sulfonate as the main surfactant with other non-ionic surfactants, anionic surfactants, organic solvents and sodium chloride. Compared with the prior art, the high-efficiency compound oil-displacing agent of the present invention has the characteristics of being able to effectively reduce the oil-water interfacial tension, having good compatibility with high-mineralization water, and the ability to reduce interfacial tension is not affected by the mineralization. The binary oil-displacing system formed with polymers can increase the crude oil recovery rate by more than 20%.

[0004] One of the main mechanisms of chemical flooding is to inject high-viscosity polymers into the formation to reduce the water-oil mobility ratio, expand the swept volume, and improve the crude oil recovery rate. At present, the commonly used polymers for oil recovery in chemical flooding sites are polyacrylamide polymers, which have the characteristics of good water solubility, good viscosity, good resistance to biodegradation, easy availability of raw materials, and low price.

[0005] At present, the general method of oil field polymerization is to prepare the mother liquor with clean water and then dilute it with oil field produced water. Since oil field produced water generally contains reducing ions Fe 2+, sulfide and sulfate-reducing bacteria. Sulfide is produced by sulfate-reducing bacteria reducing sulfate ions in water. When the reducing substances in oilfield produced water (such as reducing ions Fe 2+ When the reducing substances (such as sulfur compounds, sulfides) come into contact with the polymer mother liquor prepared with clean water, the reducing substances are easy to react with the oxygen in the clean water to produce active free radicals. The active free radicals will attack the polymer molecular chains, causing the molecular chains to break and the degree of polymerization to decrease, which will eventually lead to a significant decrease in the injection viscosity of the polymer, thereby affecting the chemical flooding effect.

[0006] The key to solving the above problems is to prevent the reaction between reducing ions and oxygen to produce free radicals, inhibit the chemical degradation of polymers by free radicals, and increase the viscosity of the polymer in chemical flooding injection wells. There are currently two ways to solve the above problems:

[0007] Method 1: By aerating the incoming water (oilfield produced water), the reducing substances in the produced water of the oilfield are oxidized. The oxidized reducing substances are no longer reducing, so they cannot combine with oxygen to produce free radicals, thereby inhibiting the degradation of polymers by free radicals. However, aerating the incoming water requires the construction of a large buffer tank, which increases ground construction, and the content of reducing substances in produced water is unstable. Excessive aeration will introduce more oxygen, resulting in poor long-term stability of the polymer in the formation. Insufficient aeration will prevent the reducing substances from being completely removed and will still combine with oxygen to produce free radicals that degrade the polymer.

[0008] Method 2: Add denitrifying bacteria to the produced water of the oil field and add a nutrient solution that matches it, and use the biological competitive exclusion effect to inhibit the growth of sulfate-reducing bacteria, thereby inhibiting the production of sulfide. However, the microbial competition method requires a certain reaction time to remove sulfate-reducing bacteria, so a large buffer tank is also required. At the same time, the microbial competition method can only inhibit the production of sulfide, but cannot eliminate Fe in the water. 2+ . Summary of the invention

[0009] Purpose of the invention: At present, most of the polymer preparation in oil fields uses oil field produced water to dilute the polymer mother liquor, and oil field produced water generally contains reducing ions Fe 2+ , sulfide and sulfate-reducing bacteria. In the process of diluting the polymer mother liquor, the reducing substances in the oilfield produced water (such as reducing ions Fe 2+ and sulfide) undergoes redox reaction with oxygen in water to generate free radicals, which will degrade the polymer, resulting in reduced injection viscosity, seriously affecting the chemical flooding effect. The present invention provides a preservative stock solution suitable for oilfield produced water polymerization and its preparation method and application. The preservative stock solution of the present invention can sterilize and inhibit the generation of sulfide in water, and it can also combine with free radicals generated in water to inhibit the attack of free radicals on the main chain of the polymer and improve the injection viscosity of the polymer.

[0010] Technical solution: The adhesive stock solution suitable for the polymerization of oilfield produced water is composed of the following components based on the total weight of the adhesive stock solution:

[0011]

[0012] The balance is nonionic surfactant.

[0013] Furthermore, the nonionic surfactant is composed of a free radical scavenger and a complexing agent. Based on the total mass of the nonionic surfactant, the free radical scavenger accounts for 50%-80%, and the remainder is the complexing agent.

[0014] Furthermore, the free radical scavenger accounts for 60%-80%, and the remainder is the complexing agent.

[0015] Furthermore, the free radical scavenger is at least one of decaglycerol monolaurate, hexaglycerol monolaurate, decaglycerol caprylate, hexaglycerol caprylate, decaglycerol monocaprate, and hexaglycerol monocaprate.

[0016] Furthermore, the complexing agent is at least one of coconut oil diethanolamide, lauric acid diethanolamide, coconut oil amide monoethanolamide, lauric acid monoethanolamide, oleic acid diethanolamide, and stearic acid diethanolamide.

[0017] Furthermore, the zwitterionic surfactant is at least one of lauramidopropyl hydroxysulfobetaine, cocoamidopropyl hydroxysulfobetaine, hexadecanoamidopropyl hydroxypropyl sulfobetaine, oleamidopropyl hydroxysulfobetaine, and erucamidopropyl hydroxysulfobetaine.

[0018] Furthermore, the organic solvent is a polyhydric alcohol.

[0019] Furthermore, the polyhydric alcohol is at least one of glycerol, ethylene glycol, pentaerythritol, trimethylolpropane, propylene glycol, dipropylene glycol, pentanediol and hexanediol.

[0020] Furthermore, the nitrite is at least one of sodium nitrite, potassium nitrite and ammonium nitrite.

[0021] The method for preparing the above-mentioned viscosity retaining agent stock solution suitable for oilfield produced water polymerization comprises the following steps:

[0022] (1) adding a formula amount of a nonionic surfactant, a formula amount of a zwitterionic surfactant, and a formula amount of an organic solvent into a reaction container, and stirring for at least 0.5 hours to obtain a mixed solution;

[0023] (2) Add 50%-70% of the formula amount of water into the reaction container, stir for at least 0.5h, then add the remaining water and the formula amount of nitrite, stir evenly to obtain the adhesive preservative stock solution.

[0024] The above-mentioned viscosity retaining agent concentrate suitable for the polymerization of oil field produced water is used in oil production.

[0025] The viscosity retaining agent stock solution prepared by the above preparation method and suitable for the polymerization of oil field produced water is used in oil production.

[0026] Furthermore, the specific steps are as follows:

[0027] (1) Add the adhesive preservative stock solution into a stirring tank, stir thoroughly and set aside;

[0028] (2) Add the viscosity retaining agent stock solution in the stirring tank directly to a certain amount of oilfield produced water, and stir evenly to obtain oilfield produced water with the viscosity retaining agent added, wherein:

[0029] The mass ratio of the adhesive preservative solution to the oilfield produced water is (0.06-0.24):1;

[0030] (3) The produced water from the oil field with the viscosity retainer added obtained in step (2) is fully mixed with a polymer mother solution of a certain concentration to obtain an oil field development polymer injection agent, and then the oil field development polymer injection agent is injected into the formation, wherein:

[0031] Based on the total mass of the oilfield development polymer injection agent, the mass concentration of the adhesion retaining agent in the oilfield development polymer injection agent is 0.03%-0.12%.

[0032] Beneficial effects: The viscosity retaining agent stock solution suitable for oilfield produced water polymerization disclosed in the present invention and its preparation method and application have the following beneficial effects:

[0033] (1) The present invention can sterilize and inhibit the generation of sulfide in water. It can also combine with free radicals generated in water to inhibit the attack of free radicals on the main chain of polymers and increase the injection viscosity of polymers.

[0034] (2) The raw materials involved are all common chemical raw materials, which are easy to obtain, have low addition concentration and low cost;

[0035] (3) It is easy to use, does not require a buffer tank, occupies a small area, and can immediately capture free radicals in the water when added to the water (capturing free radicals is an instantaneous reaction). The reaction time is extremely short (the reaction time only takes milliseconds), which greatly improves the injection viscosity of the polymer. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1To match the incoming water (i.e. oilfield produced water) containing only Fe 2+ Schematic diagram of viscosity comparison with and without adding a tackifier.

[0037] Figure 2 This is a schematic diagram comparing the viscosity of the polymerized water (i.e., produced water from oil fields) containing sulfide and sulfate-reducing bacteria with and without the addition of a viscosity-retaining agent.

[0038] Figure 3 To match the incoming water (i.e. produced water from oil fields) with Fe 2+ Schematic diagram of the viscosity comparison between adding a viscosity retaining agent and not adding a viscosity retaining agent when sulfide and sulfate-reducing bacteria are present. Specific implementation method:

[0039] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0040] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations and / or combinations thereof.

[0041] At present, most of the polymer preparation in oil fields uses oil field produced water to dilute the polymer mother liquor, and oil field produced water generally contains reducing ions Fe 2+ , sulfide and sulfate-reducing bacteria. In the process of diluting the polymer mother liquor, the reducing substances in the oilfield produced water (such as reducing ions Fe 2+ and sulfide) undergoes redox reaction with oxygen in water to generate free radicals, which will degrade the polymer, resulting in reduced injection viscosity and serious impact on chemical flooding effect. The main technical scheme of the present invention is as follows:

[0042] The adhesive stock solution suitable for the polymerization of oilfield produced water is composed of the following components based on the total weight of the adhesive stock solution:

[0043]

[0044] The balance is nonionic surfactant.

[0045] The method for preparing the above-mentioned viscosity retaining agent stock solution suitable for oilfield produced water polymerization comprises the following steps:

[0046] (1) adding a formula amount of a nonionic surfactant, a formula amount of a zwitterionic surfactant, and a formula amount of an organic solvent into a reaction container, and stirring for at least 0.5 hours to obtain a mixed solution;

[0047] (2) Add 50%-70% of the formula amount of water into the reaction container, stir for at least 0.5h, then add the remaining water and the formula amount of nitrite, stir evenly to obtain the adhesive preservative stock solution.

[0048] The above-mentioned viscosity retaining agent concentrate suitable for the polymerization of oil field produced water is used in oil production.

[0049] The viscosity retaining agent stock solution prepared by the above preparation method and suitable for the polymerization of oil field produced water is used in oil production.

[0050] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0051] Example 1

[0052] The adhesive stock solution suitable for the polymerization of oilfield produced water is composed of the following components based on the total weight of the adhesive stock solution:

[0053]

[0054]

[0055] The balance is nonionic surfactant.

[0056] Furthermore, the nonionic surfactant is composed of a free radical scavenger and a complexing agent. Based on the total mass of the nonionic surfactant, the free radical scavenger accounts for 70% and the rest is the complexing agent.

[0057] Furthermore, the free radical scavenger is a mixture of decaglycerol monolaurate and hexaglycerol monolaurate, and the mass ratio of the two is 20:15.56.

[0058] Furthermore, the complexing agent is a mixture of coconut oil diethanolamide and lauric acid diethanolamide, and the mass ratio of the two is 7.24:8.

[0059] Furthermore, the zwitterionic surfactant is lauramidopropyl hydroxysulfobetaine.

[0060] Furthermore, the organic solvent is a polyhydric alcohol.

[0061] Furthermore, the polyhydric alcohol is a mixture of propylene glycol and ethylene glycol, and the mass ratio of the two is 7.6:6.4.

[0062] Furthermore, the nitrite is sodium nitrite.

[0063] The method for preparing the above-mentioned viscosity retaining agent stock solution suitable for oilfield produced water polymerization comprises the following steps:

[0064] (1) adding a formula amount of a nonionic surfactant, a formula amount of a zwitterionic surfactant, and a formula amount of an organic solvent into a reaction container, and stirring for 1 hour to obtain a mixed solution;

[0065] (2) Add 60% of the formulated water into the reaction vessel, stir for 1 hour, then add the remaining water and the formulated amount of nitrite, stir evenly to obtain the adhesive preservative stock solution.

[0066] The above-mentioned viscosity retaining agent concentrate suitable for the polymerization of oil field produced water is used in oil production.

[0067] The viscosity retaining agent stock solution prepared by the above preparation method and suitable for the polymerization of oil field produced water is used in oil production.

[0068] Furthermore, the specific steps are as follows:

[0069] (1) Add the adhesive preservative stock solution into a stirring tank, stir thoroughly and set aside;

[0070] (2) Add the viscosity retaining agent stock solution in the stirring tank directly to a certain amount of oilfield produced water, and stir evenly to obtain oilfield produced water with the viscosity retaining agent added, wherein:

[0071] The mass ratio of the viscosity retaining agent stock solution to the oil field produced water is 0.2:1;

[0072] (3) The produced water from the oil field with the viscosity retainer added obtained in step (2) is fully mixed with a polymer mother solution of a certain concentration to obtain an oil field development polymer injection agent, and then the oil field development polymer injection agent is injected into the formation, wherein:

[0073] Based on the total mass of the oilfield development polymer injection agent, the mass concentration of the adhesion retaining agent in the oilfield development polymer injection agent is 0.1%.

[0074] Example 2

[0075] The adhesive stock solution suitable for the polymerization of oilfield produced water is composed of the following components based on the total weight of the adhesive stock solution:

[0076]

[0077] The balance is nonionic surfactant.

[0078] Furthermore, the nonionic surfactant is composed of a free radical scavenger and a complexing agent. Based on the total mass of the nonionic surfactant, the free radical scavenger accounts for 80% and the remainder is the complexing agent.

[0079] Furthermore, the free radical scavenger is a mixture of decaglycerol monolaurate and hexaglycerol monolaurate, and the mass ratio of the two is 21:14.56.

[0080] Furthermore, the complexing agent is a mixture of coconut oil diethanolamide and lauric acid diethanolamide, and the mass ratio of the two is 5:10.24.

[0081] Furthermore, the zwitterionic surfactant is cocamidopropyl hydroxysulfobetaine.

[0082] Furthermore, the organic solvent is a polyhydric alcohol.

[0083] Furthermore, the polyhydric alcohol is a mixture of propylene glycol and ethylene glycol, and the mass ratio of the two is 7.5:6.5.

[0084] Furthermore, the nitrite is potassium nitrite.

[0085] The method for preparing the above-mentioned viscosity retaining agent stock solution suitable for oilfield produced water polymerization comprises the following steps:

[0086] (1) adding a formula amount of a nonionic surfactant, a formula amount of a zwitterionic surfactant, and a formula amount of an organic solvent into a reaction container, and stirring for 2 hours to obtain a mixed solution;

[0087] (2) Add 70% of the formulated water into the reaction vessel, stir for 2 hours, then add the remaining water and the formulated amount of nitrite, stir evenly to obtain the adhesive preservative stock solution.

[0088] The above-mentioned viscosity retaining agent concentrate suitable for the polymerization of oil field produced water is used in oil production.

[0089] The viscosity retaining agent stock solution prepared by the above preparation method and suitable for the polymerization of oil field produced water is used in oil production.

[0090] Furthermore, the specific steps are as follows:

[0091] (1) Add the adhesive preservative stock solution into a stirring tank, stir thoroughly and set aside;

[0092] (2) Add the viscosity retaining agent stock solution in the stirring tank directly to a certain amount of oilfield produced water, and stir evenly to obtain oilfield produced water with the viscosity retaining agent added, wherein:

[0093] The mass ratio of the viscosity retaining agent stock solution to the oil field produced water is 0.24:1;

[0094] (3) The produced water from the oil field with the viscosity retainer added obtained in step (2) is fully mixed with a polymer mother solution of a certain concentration to obtain an oil field development polymer injection agent, and then the oil field development polymer injection agent is injected into the formation, wherein:

[0095] Based on the total mass of the oilfield development polymer injection agent, the mass concentration of the adhesion retaining agent in the oilfield development polymer injection agent is 0.12%.

[0096] Example 3

[0097] The adhesive stock solution suitable for the polymerization of oilfield produced water is composed of the following components based on the total weight of the adhesive stock solution:

[0098]

[0099] The balance is nonionic surfactant.

[0100] Furthermore, the nonionic surfactant is composed of a free radical scavenger and a complexing agent. Based on the total mass of the nonionic surfactant, the free radical scavenger accounts for 50% and the rest is the complexing agent.

[0101] In another embodiment, the free radical scavenger accounts for 60%-80%, and the remainder is the complexing agent.

[0102] Furthermore, the free radical scavenger is a mixture of equal mass ratios of decaglycerol monolaurate, hexaglycerol monolaurate, decaglycerol caprylate, hexaglycerol caprylate, decaglycerol monocaprate and hexaglycerol monocaprate.

[0103] Furthermore, the complexing agent is a mixture of coconut oil diethanolamide, lauric acid diethanolamide, cocamide monoethanolamide, lauric acid monoethanolamide, oleic acid diethanolamide, and stearic acid diethanolamide in equal mass ratios.

[0104] Furthermore, the zwitterionic surfactant is a mixture of lauramidopropyl hydroxysulfobetaine, cocoamidopropyl hydroxysulfobetaine, hexadecanoamidopropyl hydroxypropyl sulfobetaine, oleamidopropyl hydroxysulfobetaine and erucamidopropyl hydroxysulfobetaine in equal mass ratios.

[0105] Furthermore, the organic solvent is a polyhydric alcohol.

[0106] Furthermore, the polyhydric alcohol is a mixture of equal masses of glycerol, ethylene glycol, pentaerythritol, trimethylolpropane, propylene glycol, dipropylene glycol, pentanediol and hexanediol.

[0107] Furthermore, the nitrite is a mixture of sodium nitrite, potassium nitrite and ammonium nitrite in equal mass ratios.

[0108] In another embodiment, the nitrite is ammonium nitrite.

[0109] The method for preparing the above-mentioned viscosity retaining agent stock solution suitable for oilfield produced water polymerization comprises the following steps:

[0110] (1) adding a formulated amount of a nonionic surfactant, a formulated amount of a zwitterionic surfactant, and a formulated amount of an organic solvent into a reaction container, and stirring for 0.5 hours to obtain a mixed solution;

[0111] (2) Add 50% of the formulated water into the reaction container, stir for 0.5 h, then add the remaining water and the formulated amount of nitrite, stir evenly to obtain the adhesive preservative stock solution.

[0112] The above-mentioned viscosity retaining agent concentrate suitable for the polymerization of oil field produced water is used in oil production.

[0113] The viscosity retaining agent stock solution prepared by the above preparation method and suitable for the polymerization of oil field produced water is used in oil production.

[0114] Furthermore, the specific steps are as follows:

[0115] (1) Add the adhesive preservative stock solution into a stirring tank, stir thoroughly and set aside;

[0116] (2) Add the viscosity retaining agent stock solution in the stirring tank directly to a certain amount of oilfield produced water, and stir evenly to obtain oilfield produced water with the viscosity retaining agent added, wherein:

[0117] The mass ratio of the viscosity retaining agent stock solution to the oil field produced water is 0.06:1;

[0118] (3) The produced water from the oil field with the viscosity retainer added obtained in step (2) is fully mixed with a polymer mother solution of a certain concentration to obtain an oil field development polymer injection agent, and then the oil field development polymer injection agent is injected into the formation, wherein:

[0119] Based on the total mass of the oilfield development polymer injection agent, the mass concentration of the adhesion retaining agent in the oilfield development polymer injection agent is 0.03%.

[0120] Embodiment 4-10

[0121] The same as Example 1, the only difference is that the free radical scavenger and / or complexing agent is different:

[0122]

[0123] Examples 11-19

[0124] It is roughly the same as Example 1, except that the polyhydric alcohol is different:

[0125]

[0126]

[0127] Verification example:

[0128] Embodiment 20

[0129] This example is mainly used to illustrate that the viscosity retaining agent stock solution suitable for oil field produced water polymerization in the Shengli Oilfield Shengli Oil Production Plant contains only Fe 2+ How to use and the effects of use.

[0130] The specific application steps are as follows:

[0131] (1) Take the viscosity retaining agent solution suitable for oil field produced water obtained in Preparation Example 1 and add it to a volume of 1.6m 3 Mix in a mixing tank and stir thoroughly.

[0132] (2) Use a booster pump to add the high-efficiency viscosity retainer concentrate directly into the Shengli Oilfield polywater (polywater Fe 2+ Content 8mg / L).

[0133] (3) High-pressure water with a tackifier added thereto is mixed with a pressurized 5000 mg / L polymer mother liquor. The polymer concentration after mixing is 0.25%, and the tackifier concentration is 0.04%.

[0134] (4) Test the viscosity of the polymer after adding the adhesive and compare it with the viscosity of the polymer without the adhesive. Figure 1 shown.

[0135] Depend on Figure 1 The comparison results show that after adding the adhesive, the viscosity of the polymer mixture increased from 16.5mPa·s to 47.5mPa·s. Therefore, adding an adhesive can inhibit the 2+ Degrade the polymer under the presence of conditions and increase the injection viscosity.

[0136] Embodiment 21

[0137] This embodiment is mainly used to illustrate the use method and effect of the viscosity retaining agent stock solution suitable for oil field produced water polymerization of the present invention when it contains only sulfide and sulfate-reducing bacteria at the polymerization site of Gudong Oil Production Plant of Shengli Oilfield.

[0138] The specific application steps are as follows:

[0139] (1) Take the viscosity retaining agent stock solution suitable for oilfield produced water prepared in Preparation Example 2 and add it to a volume of 1.5m 3 Mix in a mixing tank and stir thoroughly.

[0140] (2) Using a booster pump, the high-efficiency viscosity retaining agent concentrate was directly added to the polywater from the Gudong Oilfield (the sulfide content of the polywater was 2.3 mg / L, and the sulfate-reducing bacteria were 700 / mL).

[0141] (3) High-pressure water with a tackifier added thereto is mixed with a pressurized 5000 mg / L polymer mother liquor. The polymer concentration after mixing is 0.24%, and the tackifier concentration is 0.05%.

[0142] (4) Test the viscosity of the polymer after adding the adhesive and compare it with the viscosity of the polymer without the adhesive. Figure 2 shown.

[0143] Depend on Figure 2 The comparison results show that after adding the viscosity-preserving agent, the viscosity of the polymer after mixing increases from 22.5 mPa·s to 67.5 mPa·s. Therefore, adding the viscosity-preserving agent can inhibit the degradation of the polymer in the presence of sulfide and sulfate-reducing bacteria and increase the injection viscosity.

[0144] Embodiment 22

[0145] This example is mainly used to illustrate that the viscosity retaining agent stock solution suitable for oil field produced water polymerization of the present invention contains Fe at the polymerization site of the Gudao Oil Production Plant of Shengli Oilfield. 2+ , sulfide and sulfate-reducing bacteria.

[0146] The specific application steps are as follows:

[0147] (1) Take the viscosity retaining agent stock solution prepared in Example 1, which is suitable for the polymerization of oil field produced water, and add it to a volume of 1.5m 3 Mix in a mixing tank and stir thoroughly.

[0148] (2) Using a booster pump, add the preservative concentrate suitable for oilfield produced water directly into the water from the Gudao Oil Production Plant (water from Fe 2+ content 8.8mg / L, sulfide content 1.2mg / L, sulfate-reducing bacteria 600 / mL).

[0149] (3) High-pressure water with a tackifier added thereto is mixed with a pressurized 5000 mg / L polymer mother liquor. The polymer concentration after mixing is 0.25%, and the tackifier concentration is 0.06%.

[0150] (4) Test the viscosity of the polymer after adding the adhesive and compare it with the viscosity of the polymer without the adhesive. Figure 3 shown.

[0151] Depend on Figure 3 The comparison results show that after adding the adhesive, the viscosity of the polymer mixture increased from 18.5mPa·s to 76.6mPa·s. Therefore, adding the adhesive can simultaneously inhibit the 2+ , the degradation of polymers in the presence of sulfide and sulfate-reducing bacteria increases the injection viscosity.

[0152] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. The viscosity retaining agent stock solution suitable for oilfield produced water polymerization is characterized by: Based on the total weight of the adhesive stock solution, the adhesive stock solution consists of the following components: The balance is nonionic surfactant.

2. The viscosity retaining agent stock solution suitable for oilfield produced water polymerization according to claim 1, characterized in that: The nonionic surfactant is composed of a free radical scavenger and a complexing agent. Based on the total mass of the nonionic surfactant, the free radical scavenger accounts for 50%-80%, and the rest is the complexing agent.

3. The viscosity retaining agent stock solution suitable for oilfield produced water polymerization as claimed in claim 2, characterized in that: The free radical scavenger accounts for 60%-80%, and the remainder is the complexing agent.

4. The viscosity retaining agent stock solution suitable for oilfield produced water polymerization as claimed in claim 2, characterized in that: The free radical scavenger is at least one of decaglycerol monolaurate, hexaglycerol monolaurate, decaglycerol caprylate, hexaglycerol caprylate, decaglycerol monocaprate and hexaglycerol monocaprate.

5. The viscosity retaining agent stock solution suitable for oilfield produced water polymerization as claimed in claim 2, characterized in that: The complexing agent is at least one of coconut oil diethanolamide, lauric acid diethanolamide, coconut oil amide monoethanolamide, lauric acid monoethanolamide, oleic acid diethanolamide, and stearic acid diethanolamide.

6. The viscosity retaining agent stock solution suitable for oilfield produced water polymerization according to claim 1, characterized in that: The zwitterionic surfactant is at least one of lauramidopropyl hydroxysulfobetaine, cocoamidopropyl hydroxysulfobetaine, hexadecanoamidopropyl hydroxypropyl sulfobetaine, oleamidopropyl hydroxysulfobetaine, and erucamidopropyl hydroxysulfobetaine.

7. The viscosity retaining agent stock solution suitable for oilfield produced water polymerization according to claim 1, characterized in that: The organic solvent is a polyhydric alcohol.

8. The viscosity retaining agent stock solution suitable for oilfield produced water polymerization according to claim 7, characterized in that: The polyhydric alcohol is at least one of glycerol, ethylene glycol, pentaerythritol, trimethylolpropane, propylene glycol, dipropylene glycol, pentanediol and hexanediol.

9. The viscosity retaining agent stock solution suitable for oilfield produced water polymerization according to claim 1, characterized in that: The nitrite is at least one of sodium nitrite, potassium nitrite and ammonium nitrite.

10. The method for preparing the viscosity retaining agent stock solution suitable for oilfield produced water polymerization according to any one of claims 1 to 9, comprising the following steps: (1) adding a formula amount of a nonionic surfactant, a formula amount of a zwitterionic surfactant, and a formula amount of an organic solvent into a reaction container, and stirring for at least 0.5 hours to obtain a mixed solution; (2) Add 50%-70% of the formula amount of water into the reaction container, stir for at least 0.5h, then add the remaining water and the formula amount of nitrite, stir evenly to obtain the adhesive preservative stock solution.

11. Use of the viscosity retaining agent concentrate suitable for polymerization of oilfield produced water as claimed in any one of claims 1 to 9 in oil production.

12. Use of the viscosity retaining agent concentrate prepared by the preparation method of claim 10 and suitable for polymerization with oilfield produced water in oil production.

13. The use according to claim 11 or 12, characterized in that The specific steps are as follows: (1) Add the adhesive preservative stock solution into a stirring tank, stir thoroughly and set aside; (2) Add the viscosity retaining agent stock solution in the stirring tank directly to a certain amount of oilfield produced water, and stir evenly to obtain oilfield produced water with the viscosity retaining agent added, wherein: The mass ratio of the adhesive preservative solution to the oilfield produced water is (0.06-0.24):1; (3) The produced water from the oil field with the viscosity retainer added obtained in step (2) is fully mixed with a polymer mother solution of a certain concentration to obtain an oil field development polymer injection agent, and then the oil field development polymer injection agent is injected into the formation, wherein: Based on the total mass of the oilfield development polymer injection agent, the mass concentration of the adhesion retaining agent in the oilfield development polymer injection agent is 0.03%-0.12%.

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