Organic amine modified plant polyphenol drilling fluid additive and preparation method and application thereof

Abstract

The present invention relates to the technical field of petrochemical industry, specifically to an organic amine modified plant polyphenol drilling fluid additive and a preparation method and application thereof, wherein an organic amine is used to perform a modification reaction on oxidized plant polyphenols to obtain an organic amine modified plant polyphenol drilling fluid additive. The organic amine includes one or more of a monoamine with 12-20 carbon atoms or a diamine with 4-16 carbon atoms. The present invention utilizes the quinone carbonyl structure after oxidation of plant polyphenols to perform a Mannich reaction with an organic amine, and the carboxyl group can also react with the organic amine, thereby successfully modifying the plant polyphenols. The additive can effectively improve the high temperature and high pressure rheological stability and sedimentation stability of the drilling fluid.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical engineering, and in particular to an organic amine-modified plant polyphenol drilling fluid additive, a preparation method and application thereof. Background Art

[0002] Plant polyphenols are forest byproducts second only to hemicellulose, cellulose and lignin in terms of production in my country. They are naturally macromolecular compounds with a phenolic hydroxyl group structure and are widely found in plants. As a type of abundant and renewable green resource, plant polyphenols will surely become one of the important resource treasures for human use as other disposable resources are gradually consumed and environmental protection requirements are improved. Plant polyphenols have complex and diverse structures, most of which contain active groups such as phenolic hydroxyl groups, ester groups, and ether groups. They can be combined with a variety of substances to have antioxidant and ion adsorption effects. This makes plant polyphenols, a functional material, widely used in the fields of pharmaceutical processing, food production, sewage treatment, etc. However, plant polyphenols also have structural deficiencies. In order to make them more fully used in industrial production, their structure needs to be modified. For example, plant polyphenols are oxidized to form a quinone structure, which can react with organic amines to introduce carbon-nitrogen bonds, thereby increasing the stability of their overall structure.

[0003] With the decreasing petroleum resources and the pollution caused by a large number of refractory synthetic polymers to the environment, the research on the preparation of drilling fluid additives with natural polyphenols has attracted widespread attention. The density of drilling fluid is crucial to the pressure control of the formation, and the control of rheology and sedimentation stability is one of the main technical difficulties in high-density drilling fluid technology. Due to the influence of factors such as gravity, heavy particulate matter tends to settle from the suspension. This significant change in drilling fluid density caused by the sedimentation of barite or other weighting materials in high-angle wells is designated as "sedimentation" in the drilling industry. Sedimentation may lead to various drilling and completion problems, such as: during the drilling process, the sedimentation of weighting materials leads to insufficient density of drilling fluid used to control formation pressure, causing problems such as well control difficulties; in addition, the settled weighting materials may hinder the normal operation of the casing or cause incomplete displacement during cementing operations. It can be seen that it is very important to ensure the suspension of high-temperature and high-density drilling fluids.

[0004] In order to solve the problem of difficult-to-control rheology and stability of high-temperature and high-density drilling fluids used in high-temperature deep wells, Li Ziyu and others used polyetheramine D-2000, sebacic acid and polyols to react to produce the desired functional groups of amide and ester groups, and used the polar groups and long chains in the molecules to form a grid structure. 3The preferred addition amount is 1%. Under the condition of 150°C, the apparent viscosity of the drilling fluid is 37mPa·s, the dynamic shear force is 10.5Pa, the demulsification voltage is >700V, the static sedimentation coefficient SF=0.504, and the dynamic sedimentation coefficient VSST=0.081g / cm 3 The drilling fluid has good rheological properties and suspension stability, and good electrical stability (Li Ziyu, Yu Peizhi. Synthesis and evaluation of oil-based drilling fluid cutting agent [J]. Applied Chemical Industry, 2022, (05): 1252-1255.). However, the preparation method and raw material composition are relatively complex, which is not conducive to reducing costs, and the raw material has poor biodegradability, which is not conducive to promotion and application.

[0005] Therefore, it is necessary to provide an organic amine modified plant polyphenol drilling fluid additive and a preparation method thereof to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide an organic amine modified plant polyphenol drilling fluid additive and a preparation method and application thereof. Plant polyphenols are used as raw materials, organic amines are used to modify the plant polyphenols, and an organic amine modified plant polyphenol drilling fluid additive is synthesized to achieve the purpose of improving the rheology and sedimentation stability of the drilling fluid.

[0007] To achieve the above objectives, in a first aspect, the present invention provides a method for preparing an organic amine-modified plant polyphenol drilling fluid additive, wherein oxidized plant polyphenols are subjected to a modification reaction using an organic amine to obtain an organic amine-modified plant polyphenol drilling fluid additive.

[0008] With the continuous deepening of exploration and development, under the action of high temperature and high pressure at the bottom of the well, the oil-based drilling fluid treatment agent will degrade and solidify, resulting in the system's stratified accumulation and sedimentation and the rheological properties being difficult to control, thereby causing wellbore instability, well leakage, well control and other problems. The drilling fluid additive obtained by the present invention can ensure the drilling safety of high-temperature and high-pressure wells, prevent the drilling fluid from sending and settling, and effectively improve the high-temperature and high-pressure rheological stability and sedimentation stability of the drilling fluid.

[0009] Further, the organic amine includes one or more of a monoamine with 12 to 20 carbon atoms or a diamine with 4 to 16 carbon atoms. The monoamine is selected from one or more of dodecylamine, pentadecylamine, hexadecylamine, octadecylamine, and eicosylamine, preferably octadecylamine; the diamine is selected from one or more of butanediamine, pentamethylenediamine, hexamethylenediamine, octanediamine, dodecanediamine, and hexadecanediamine, preferably 1,6-hexanediamine.

[0010] Furthermore, the plant polyphenols include one or more of gallic acid, tannic acid and tannin.

[0011] The invention is based on plant polyphenols with pyrogallol structure such as gallic acid, tannic acid and tannin, which are oxidized to orthoquinone structure under alkaline conditions, and the quinone carbonyl structure reacts with organic amine to produce Mannich reaction, and the carboxylic acid in the plant polyphenol containing carboxylic acid easily reacts with the organic amine to generate compounds containing carbonyl, amino and other structures, and the drilling fluid additive obtained in this way can effectively improve the high temperature and high pressure rheological stability and sedimentation stability of the drilling fluid. When the types and contents of the plant polyphenols and amines are changed, the drilling fluid additive with better rheological stability after high temperature aging can also be obtained.

[0012] Furthermore, the modification reaction temperature is room temperature-75°C, and the time is 1-8 hours; preferably, the temperature is 45-75°C, and the time is 2-4 hours. This temperature range is more conducive to the occurrence of the reaction.

[0013] Furthermore, the oxidation of the plant polyphenols is carried out under alkaline conditions, preferably using a NaOH solution to adjust the pH value to alkaline.

[0014] Furthermore, when the organic amine is a monoamine, the molar ratio of the organic amine to the plant polyphenol is (1-10):1; when the organic amine is a diamine, the molar ratio of the organic amine to the plant polyphenol is (0.5-5):1.

[0015] Further, the following steps are included:

[0016] S1, dissolving the plant polyphenols in a solvent and adjusting the pH value to 8-10;

[0017] S2, adding an organic amine to the solution obtained in step S1, and reacting at room temperature -75°C for 1-8h;

[0018] S3, cooling to room temperature, filtering and drying, and grinding to obtain an organic amine-modified plant polyphenol drilling fluid additive.

[0019] Furthermore, the solvent in step S1 is one or more of water, alcohol and ether solvents, preferably water. The alcohol is one or more of ethanol, propanol and isopropanol; the ether is ether.

[0020] In step S2, the organic amine is first dissolved in an organic solvent and then added to the solution obtained in step S1, preferably in three additions; the organic solvent is miscible with the solvent in step S1, and is preferably ethanol.

[0021] In a second aspect, the present invention provides an organic amine-modified plant polyphenol drilling fluid additive, which is prepared by any of the preparation methods described above.

[0022] In a third aspect, the present invention provides an application of the organic amine-modified plant polyphenol drilling fluid additive as described above, which is used as an anti-settling agent for drilling fluid.

[0023] Furthermore, the amount of the organic amine modified plant polyphenol drilling fluid additive is 0.5-5% by mass of the drilling fluid, preferably 1-3%;

[0024] Furthermore, the drilling fluid includes white oil, emulsifier, organic soil, CaCl2 aqueous solution, CaO, fluid loss reducer and barite.

[0025] Based on 100 mL of white oil, the added amount of each component is as follows: emulsifier 8-12 g, organic soil 2.8-3.3 g, 15-25% CaCl2 aqueous solution 20-30 mL, CaO 2-3 g, filtrate reducer 4-6 g and barite 250-300 g.

[0026] The beneficial effects of the present invention are as follows:

[0027] The organic amine modified plant polyphenol drilling fluid additive provided by the present invention uses organic amines to modify plant polyphenols to obtain a high-temperature resistant drilling fluid anti-settling agent, which can effectively improve the high-temperature and high-pressure rheological stability and sedimentation stability of the drilling fluid and conforms to the development concept of green, environmental protection, high efficiency and harmlessness. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 Wherein ac are FT-IR spectra of gallic acid raw material and additives obtained in Example 1 and Example 2, respectively;

[0030] Figure 2 Wherein, ac are FT-IR spectra of tannin raw material and additives obtained in Example 3 and Example 4, respectively;

[0031] Figure 3 Wherein ac are FT-IR spectra of tannin extract raw material and additives obtained in Example 5 and Example 6 respectively;

[0032] Figure 4 This is a physical picture of the additive obtained in Example 1. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] An organic amine modified plant polyphenol drilling fluid additive and a preparation method thereof, comprising the following steps:

[0036] (1) Weigh 8 g of gallic acid and dissolve it in 40 mL of deionized water. Heat until completely dissolved and stir evenly at 300 r / min.

[0037] (2) Adjust the pH to 8.5 with 10% NaOH solution.

[0038] (3) Weigh 12.8 g of octadecylamine and dissolve it in 64 mL of ethanol. Stir well.

[0039] (4) First, transfer gallic acid into a three-necked flask and stir continuously. Then, add octadecylamine into the three-necked flask in three portions and react in a water bath at 50°C for 2 h.

[0040] (5) Cool to room temperature, filter and dry to obtain the product.

[0041] (6) Grinding the product to obtain an organic amine-modified plant polyphenol drilling fluid additive.

[0042] Example 2

[0043] An organic amine modified plant polyphenol drilling fluid additive and a preparation method thereof, comprising the following steps:

[0044] (1) Weigh 10 g of gallic acid and dissolve it in 50 mL of deionized water. Heat until completely dissolved and stir evenly at 300 r / min.

[0045] (2) Adjust the pH to 8.5 with 10% NaOH solution.

[0046] (3) Weigh 12.65 g of 1,6-hexanediamine and dissolve it in 64 mL of ethanol. Stir well.

[0047] (4) First, transfer gallic acid into a three-necked flask and stir continuously. Then, add 1,6-hexanediamine into the three-necked flask in three portions and heat in a water bath at 50°C for 2 h.

[0048] (5) Cool to room temperature, filter and dry to obtain the product.

[0049] (6) Grinding the product to obtain an organic amine modified plant polyphenol drilling fluid additive. Figure 4 shown.

[0050] like Figure 1 As shown, a is the infrared spectrum of gallic acid, b and c are the infrared spectra of Example 1 and Example 2, respectively. In the a spectrum, 3490cm -1 The stretching vibration peak of -OH in the carboxyl group is 3270 cm -1 The stretching vibration peak of phenolic hydroxyl group is 1690 cm -1 The stretching vibration peak of C=O is at 1600cm -1 The peak at 2930cm is the stretching vibration peak of the benzene ring. -1 、2850cm -1 The stretching vibration peak of -CH2 is 721cm -1 The bending vibration peak of -CH2 is 1550cm -1 The bending vibration peak of NH is at 1340cm -1 The peak at the center is the stretching vibration peak of the newly generated CN, proving that the organic amine successfully modified the gallic acid.

[0051] Example 3

[0052] An organic amine modified plant polyphenol drilling fluid additive and a preparation method thereof, comprising the following steps:

[0053] (1) Weigh 18.9 g of tannic acid and dissolve it in 95 mL of deionized water. Stir the mixture at a speed of 300 r / min.

[0054] (2) Adjust the pH to 8.5 with 10% NaOH solution.

[0055] (3) Weigh 3 g of octadecylamine and dissolve it in 15 mL of ethanol. Stir well.

[0056] (4) First, transfer tannic acid into a three-necked flask and stir continuously. Then, add octadecylamine into the three-necked flask in three portions and react in a water bath at 50°C for 2 hours.

[0057] (5) Cool to room temperature, filter and dry to obtain the product.

[0058] (6) Grinding the product to obtain an organic amine-modified plant polyphenol drilling fluid additive.

[0059] Example 4

[0060] An organic amine modified plant polyphenol drilling fluid additive and a preparation method thereof, comprising the following steps:

[0061] (1) Weigh 18 g of tannic acid and dissolve it in 90 mL of deionized water. Stir the mixture at a speed of 300 r / min.

[0062] (2) Adjust the pH to 8.5 with 10% NaOH solution.

[0063] (3) Weigh 2.3 g of 1,6-hexanediamine and dissolve it in 11.5 mL of ethanol. Stir well.

[0064] (4) First transfer tannic acid into a three-necked flask and stir continuously. Then add 1,6-hexanediamine into the three-necked flask in three portions and heat in a water bath at 50°C for 2 h.

[0065] (5) Cool to room temperature, filter and dry to obtain the product.

[0066] (6) Grinding the product to obtain an organic amine-modified plant polyphenol drilling fluid additive.

[0067] like Figure 2 As shown, a is the infrared spectrum of the tannic acid raw material, b and c are the infrared spectra of Example 3 and Example 4, respectively. In the a spectrum, 3300cm -1 The stretching vibration peak of phenolic hydroxyl group is 1690 cm -1 The stretching vibration peak of C=O is at 1600cm -1 The peak at 2930cm is the stretching vibration peak of the benzene ring. -1 、2850cm -1 The stretching vibration peak of -CH2 is 729cm -1 The bending vibration peak of -CH2 is 1550cm -1 The bending vibration peak of NH is at 1340cm -1 The peak at the center is the stretching vibration peak of the newly generated CN, proving that the organic amine successfully modified the tannic acid.

[0068] Example 5

[0069] An organic amine modified plant polyphenol drilling fluid additive and a preparation method thereof, comprising the following steps:

[0070] (1) Weigh 40 g of tannin extract and dissolve it in 120 mL of deionized water. Stir evenly at a speed of 300 r / min.

[0071] (2) Adjust the pH to 8.5 with 10% NaOH solution.

[0072] (3) Weigh 20 g of octadecylamine and dissolve it in 100 mL of ethanol. Stir well.

[0073] (4) First transfer the tannin extract into a three-necked flask and stir continuously. Then add octadecylamine into the three-necked flask in three portions and heat in a water bath at 50°C for 2 hours.

[0074] (5) Cool to room temperature, filter and dry to obtain the product.

[0075] (6) Grinding the product to obtain an organic amine-modified plant polyphenol drilling fluid additive.

[0076] Example 6

[0077] An organic amine modified plant polyphenol drilling fluid additive and a preparation method thereof, comprising the following steps:

[0078] (1) Weigh 50 g of tannin extract and dissolve it in 250 mL of deionized water. Stir evenly at a speed of 300 r / min.

[0079] (2) Adjust the pH to 8.5 with 10% NaOH solution.

[0080] (3) Weigh 20 g of 1,6-hexanediamine and dissolve it in 100 mL of ethanol. Stir well.

[0081] (4) First transfer the tannin extract into a three-necked flask and stir continuously. Then add 1,6-hexanediamine into the three-necked flask in three portions and heat in a water bath at 50°C for 2 hours.

[0082] (5) Cool to room temperature, filter and dry to obtain the product.

[0083] (6) Grinding the product to obtain an organic amine modified plant polyphenol drilling fluid additive

[0084] like Figure 3 As shown, a is the infrared spectrum of the tannin extract raw material, b and c are the infrared spectra of Example 5 and Example 6 respectively. In the a spectrum, 3400cm -1 The stretching vibration peak of phenolic hydroxyl group is 1570 cm -1 、1420cm -1 The peak at 1110 cm is the stretching vibration peak of the benzene ring. -1 The symmetrical stretching vibration peak of COC is at 2930cm -1 、2850cm -1 The stretching vibration peak of -CH2 is 729cm -1 The bending vibration peak of -CH2 is 1560cm -1 The bending vibration peak of NH is at 1330cm -1 The peak at is the stretching vibration peak of the newly generated CN, proving that the organic amine has successfully modified the tannin extract.

[0085] Comparative Example 1

[0086] An organic amine modified plant polyphenol drilling fluid additive and a preparation method thereof, comprising the following steps:

[0087] (1) Weigh 8 g of gallic acid and 12.8 g of octadecylamine and mix well.

[0088] (2) Grinding the mixture to obtain an organic amine-modified plant polyphenol drilling fluid additive.

[0089] Comparative Example 2

[0090] An organic amine modified plant polyphenol drilling fluid additive and a preparation method thereof, comprising the following steps:

[0091] (1) Weigh 18.9 g of tannic acid and dissolve it in 95 mL of deionized water. Stir the mixture at a speed of 300 r / min.

[0092] (2) Weigh 3 g of octadecylamine and dissolve it in 15 mL of ethanol. Stir well.

[0093] (7) First, transfer tannic acid into a three-necked flask and stir continuously. Then, add octadecylamine into the three-necked flask in three portions and react in a water bath at 50°C for 2 h.

[0094] (8) Cool to room temperature and dry to obtain the product.

[0095] (9) Grinding the product to obtain an organic amine-modified plant polyphenol drilling fluid additive.

[0096] Comparative Example 3

[0097] Tannin extract powder is directly used as a drilling fluid additive.

[0098] Test 1: Compatibility test

[0099] The compatibility of drilling fluid additives in oil-based drilling fluids was evaluated to determine whether the drilling fluid additives could be well dispersed and suspended in the oil-based drilling fluids without affecting the rheological properties and stability of the oil-based drilling fluids.

[0100] Preparation of oil-based drilling fluid slurry: Add 240mL white oil to a high stirring cup, and add 24g main emulsifier HT-MUL, 7.5g organic soil, 60mL 20% CaCl2 aqueous solution, 6g CaO, 12g filtrate reducer, 650g density 1.8g / cm 3 The barite is stirred for 20 minutes, and then each time a treatment agent is added, it is stirred for 10 minutes until all the raw materials are added and stirred together for 40 minutes to obtain the oil-based drilling fluid base fluid.

[0101] The prepared drilling fluid samples were cooled to room temperature before and after aging (180℃, 72h), and tested at room temperature using a six-speed viscometer. The stable readings of Φ600, Φ300, Φ200, Φ100, Φ6, and Φ3 were recorded in turn at different speeds. Apparent viscosity: AV = ηapparent = Φ600 / 2mPa·s; plastic viscosity: PV = ηplastic = Φ600-Φ300mPa·s; dynamic shear force: YP = τ0 = (Φ300-PV) / 2 = Φ300-Φ600 / 2Pa; dynamic plastic ratio: YP / PV = (Φ300-Φ600 / 2) / (Φ600-Φ300).

[0102] Barite Sedimentation Test Method

[0103] The barite sedimentation test method is established for different sedimentation conditions, such as simulated static conditions, dynamic conditions, tilt angles, flow loops, high temperature and high pressure, etc. It is planned to use the static sedimentation test method.

[0104] Static sedimentation test is a method to evaluate the sedimentation tendency of drilling fluid under static conditions in the wellbore. Drilling fluid is added to a stainless steel tank and placed statically for a period of time at a specific temperature. The density of the upper part of the drilling fluid column (the lower layer of free liquid) is measured. top and the density ρ at the bottom bottom The calculation formula of static sedimentation factor SF is as follows.

[0105] SF=ρ bottom / (ρ bottom +ρ top )

[0106] When SF is 0.50, it means that no static sedimentation occurs, and when SF is greater than 0.52, it means that the static sedimentation stability is poor. The operation method is simple and suitable for field use. However, when calculating the static sedimentation factor, the syneresis effect is not considered, that is, the upper free liquid is not involved in the calculation, and there will be a certain deviation between the experimental results and the true value.

[0107] The rheological parameters of the drilling fluid were tested with reference to the national standard GB / T 29170-2012 Laboratory Test of Drilling Fluids in the Petroleum and Natural Gas Industry, and the results are shown in Table 1.

[0108] Table 1 Effects of additives prepared in Examples 1-6 and Comparative Examples 1-3 on drilling fluid rheology, demulsification voltage and sedimentation performance

[0109]

[0110]

[0111] As can be seen from Table 1, after adding the product of the embodiment of the present invention, the rheological parameters of the drilling fluid before and after aging change little, indicating that the temperature resistance of the product of the embodiment of the present invention is excellent, and the drilling fluid has low viscosity and viscosity stability. The demulsification voltage of Examples 1-4 is as high as more than 1000V, and the demulsification voltage of Examples 5-6 is also above 400V, indicating that the emulsion formed has strong stability. The sedimentation factor SF is about 0.51, which has a very good anti-barite sedimentation effect. However, Comparative Example 3 uses unmodified tannin extract, and soft sedimentation occurs after aging. Comparative Example 1 is directly physically mixed, so the sedimentation factor SF increases, and the demulsification voltage is significantly reduced. Comparative Example 2 does not use alkali oxidation, and the sedimentation factor SF also increases, and the demulsification voltage is significantly reduced.

[0112] In Comparative Examples 1-3, the reaction process is simplified to direct mixing without oxidation treatment and reaction process; the proportion of organic amine is reduced and plant polyphenol raw materials are directly used. After the drilling fluid is aged, the demulsification voltage drops sharply to below 400V, proving that the emulsion structure of the system is destroyed and the drilling fluid cannot be used normally.

[0113] It can be seen from Examples 4-6 that after aging, the demulsification voltage does not decrease but increases, indicating that the drilling fluid additive prepared by the present invention has high temperature and high pressure rheological stability and sedimentation stability. This may be because the drilling fluid additive forms a substance that is more conducive to improving sedimentation stability at high temperature.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an organic amine modified plant polyphenol drilling fluid additive, characterized in that: The oxidized plant polyphenols are modified by organic amines to obtain an organic amine-modified plant polyphenol drilling fluid additive; the organic amines include one or more of monoamines with 12 to 20 carbon atoms or diamines with 4 to 16 carbon atoms.

2. The method for preparing the organic amine modified plant polyphenol drilling fluid additive according to claim 1, characterized in that: The plant polyphenols include one or more of gallic acid, tannic acid and tannin.

3. The method for preparing the organic amine modified plant polyphenol drilling fluid additive according to claim 1 or 2, characterized in that: The modification reaction temperature is room temperature-75°C, and the time is 1-8h; And / or, the oxidation of the plant polyphenols is carried out under alkaline conditions.

4. The method for preparing the organic amine modified plant polyphenol drilling fluid additive according to claim 3, characterized in that: The pH was adjusted to alkaline using NaOH solution.

5. The method for preparing the organic amine modified plant polyphenol drilling fluid additive according to claim 1 or 2, characterized in that: When the organic amine is a monoamine, the molar ratio of the organic amine to the plant polyphenol is (1-10):1; when the organic amine is a diamine, the molar ratio of the organic amine to the plant polyphenol is (0.5-5):

1.

6. The method for preparing the organic amine modified plant polyphenol drilling fluid additive according to claim 1 or 2, characterized in that: The following steps are involved: S1, dissolving the plant polyphenols in a solvent and adjusting the pH value to 8-10; S2, adding an organic amine to the solution obtained in step S1, and reacting at room temperature -75°C for 1-8h; S3, cooling to room temperature, filtering and drying to obtain an organic amine-modified plant polyphenol drilling fluid additive.

7. The method for preparing the organic amine modified plant polyphenol drilling fluid additive according to claim 6, characterized in that: The solvent in step S1 is one or more of water, alcohol and ether solvents; In step S3, the organic amine is first dissolved in an organic solvent and then added to the solution obtained in step S1; the organic solvent is miscible with the solvent in step S1.

8. An organic amine modified plant polyphenol drilling fluid additive, characterized in that: The method is prepared according to any one of claims 1 to 7.

9. An application of the organic amine modified plant polyphenol drilling fluid additive according to claim 8, characterized in that: Used as an anti-settling agent for drilling fluids.

10. The use of the organic amine modified plant polyphenol drilling fluid additive according to claim 9, characterized in that: The amount of the organic amine modified plant polyphenol drilling fluid additive is 0.5-5% of the mass of the drilling fluid; And / or, the drilling fluid comprises white oil, emulsifier, organic soil, CaCl2 aqueous solution, CaO, fluid loss reducer and barite.

11. The use of the organic amine modified plant polyphenol drilling fluid additive according to claim 10, characterized in that: The dosage of the organic amine modified plant polyphenol drilling fluid additive is 1-3% of the mass of the drilling fluid.

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