Clay stabilizer for oil field as well as preparation method and application of clay stabilizer

Abstract

The invention belongs to the technical field of oil exploitation and relates to a clay stabilizer for an oil field as well as a preparation method and application thereof. The preparation method comprises the following steps: adding trimethylolpropane allyl ether and potassium hydroxide into a high-pressure reaction kettle, heating, introducing ethylene oxide, carrying out heat preservation reaction, and cooling to 40 DEG C or below after the pressure is stable; adding sulfamic acid powder, carrying out heat preservation reaction, and adjusting the pH value to 7-8; transferring into a normal-pressure reactor, adding (3-acrylamidopropyl) trimethyl ammonium chloride and buffer salt, and uniformly stirring; dropwise adding an initiator, carrying out stirring reaction, heating, continuously carrying out heat preservation reaction, cooling, and adjusting the pH value to 7-8; and drying and granulating the viscous mixed solution to obtain the clay stabilizer. The clay stabilizer disclosed by the invention is low in raw material price, wide in source and simple in preparation process; meanwhile, the anti-swelling agent has the advantages of high anti-swelling rate and low mudstone loss rate.

Description

Technical Field

[0001] The invention belongs to the technical field of oil extraction and relates to a clay stabilizer for oil fields and a preparation method and application thereof. Background Art

[0002] Clay minerals are widely present in oil layers. During water injection, acidification, fracturing and other operations, clay minerals in the formation will swell when they come into contact with water or water-based substances. This expansion will squeeze the pores and throats of the formation, reduce the permeability of the reservoir, and affect the seepage and production efficiency of oil and gas. The use of clay stabilizers can inhibit the expansion of clay, maintain the stability of the reservoir pore structure, and ensure that oil and gas can be produced smoothly. For example, clay minerals such as montmorillonite will expand significantly in volume when they come into contact with water. If not controlled, it will cause serious damage to the reservoir. The use of clay stabilizers can effectively solve this problem.

[0003] Clay expansion may cause the cracking and collapse of formation rocks, which in turn damages downhole equipment and oil well casings, increasing oil field maintenance costs and downtime. By using clay stabilizers, this potential formation damage can be reduced and the service life of oil wells can be extended.

[0004] Clay minerals in oil layers are prone to particle migration under the scouring effect of fluids. These migrated clay particles will block the pores and throats of the formation, further reducing the permeability of the reservoir and affecting the production of oil and gas. Clay stabilizers can be adsorbed on the surface of clay particles, increasing the interaction between the particles, making it less likely to migrate, thereby maintaining the permeability of the reservoir.

[0005] At present, the development of clay stabilizer technology has made great progress, but it still needs to be further strengthened in terms of enhancing temperature resistance, improving long-term effectiveness, and improving anti-swelling effects.

[0006] In the paper "Synthesis and Evaluation of Small Molecule Polyamine Clay Stabilizer EM" published by Hu Xingqi et al., a polyamine clay stabilizer EM was synthesized using epichlorohydrin and methylamine, which effectively inhibited clay hydration expansion. When used alone, the optimal mass concentration range was 1-2%, and the anti-swelling rate was 86%. When compounded with 0.5% NH4C1, the anti-swelling rate was only 91%, which could not meet the requirements for reservoirs with higher anti-swelling requirements.

[0007] CN109456748B discloses a clay stabilizer for reservoir transformation and fracturing and a preparation method thereof. It comprises the following steps: (1) using p-aminophenol and epichlorohydrin as raw materials, and obtaining an intermediate product under the catalysis of sodium alcohol; (2) using the intermediate product formula and ammonia as raw materials to obtain a product, namely, a clay stabilizer for reservoir transformation and fracturing. The clay stabilizer of the invention contains a benzene ring with a high polarity, which makes it have the advantages of a general polyetheramine clay stabilizer while having a high polarity, so that after being used as a fracturing fluid additive, it is easier to discharge it, which has better protection for the environment, and is also more advantageous in the evaluation of anti-swelling rate, and has more development prospects in oil and gas field exploitation. However, there are no cations in the molecule of the invention, and the clay surface is negatively charged, which makes the clay unable to adsorb the stabilizer well, thus affecting the anti-swelling effect. Summary of the invention

[0008] The present invention aims to solve the above-mentioned deficiencies in the prior art and provides a clay stabilizer for oil fields and its preparation method and application. The clay stabilizer of the present invention has the advantages of low raw material price, wide source, simple preparation process, high anti-swelling rate and low mudstone loss rate.

[0009] In order to achieve the above objectives:

[0010] The first aspect of the present invention discloses a clay stabilizer for oil fields, wherein the molecular structure of the clay stabilizer is as follows:

[0011]

[0012] Wherein, x = 100-1000;

[0013] y = 50-1000;

[0014] n=2-20.

[0015] Preferably, the viscosity average molecular weight of the clay stabilizer is 100,000-1,000,000.

[0016] In another aspect, the present invention discloses a method for preparing the above-mentioned clay stabilizer, and the specific steps of the preparation method are as follows:

[0017] (1) Add trimethylolpropane allyl ether and potassium hydroxide to a high-pressure reactor, purge the pipeline and the reactor with nitrogen, evacuate, purge the pipeline and the reactor with nitrogen again, then slowly heat to 85-90° C., evacuate again, and introduce ethylene oxide. After the introduction is complete, keep the temperature to react, and the pressure gradually decreases. When the pressure stabilizes, stop the reaction and cool the system to below 40° C.;

[0018] (2) Add sulfamic acid powder to the above autoclave, heat at 110-130° C. for 1-2 hours, add distilled water, and adjust the pH to 7-8 with potassium hydroxide;

[0019] (3) The mixed solution is transferred to a normal pressure reactor, (3-acrylamidopropyl)trimethylammonium chloride and buffer salt are added, and stirred evenly; the initiator is added dropwise to the reactor, and after the addition is completed, the reaction is stirred until the solution begins to become viscous, and the temperature is raised to 80° C. and the reaction is continued at this temperature for 1-2 hours to obtain a viscous mixed solution, and the temperature is lowered to below 40° C. and the pH is adjusted to 7-8 with potassium hydroxide;

[0020] (4) drying and granulating the viscous mixed liquid to obtain a clay stabilizer.

[0021] In the present invention, preferably, based on 1 mole of trimethylolpropane allyl ether, the amounts of ethylene oxide, aminosulfonic acid and (3-acrylamidopropyl)trimethylammonium chloride are 4-40 mole parts, 2.5-4 mole parts and 0.5-1 mole parts respectively.

[0022] In the present invention, preferably, in step (1), the mass ratio of potassium hydroxide to trimethylolpropane allyl ether is 0.2-0.4:1.

[0023] In the present invention, preferably, in step (1), the insulation reaction temperature is 120-170°C.

[0024] In the present invention, preferably, in step (2), the mass ratio of distilled water to trimethylolpropane allyl ether is 10-30:1.

[0025] In the present invention, preferably, in step (3), the buffer salt is one of disodium hydrogen phosphate, dipotassium hydrogen phosphate, and diammonium hydrogen phosphate; more preferably, the buffer salt is one of dipotassium hydrogen phosphate and diammonium hydrogen phosphate, and the weight ratio of the buffer salt to trimethylolpropane allyl ether is 0.1-0.3:1.

[0026] Preferably, in step (3), the initiator is a mixed solution of persulfate and bisulfite, wherein the concentration of persulfate is 8-12wt%, the concentration of bisulfite is 3-5wt%, and the weight ratio of initiator to trimethylolpropane allyl ether is 0.1-0.5:1.

[0027] Preferably, the persulfate is one of sodium persulfate, potassium persulfate and ammonium persulfate.

[0028] Preferably, the bisulfite is sodium bisulfite or potassium bisulfite.

[0029] The synthetic reaction equation of the oil field clay stabilizer of the present invention is as follows:

[0030]

[0031]

[0032] The third object of the present invention is to disclose the application of the above-mentioned clay stabilizer in the development of oil and gas fields.

[0033] The oilfield clay stabilizer of the present invention is a binary high molecular polymer. The ammonium root and quaternary ammonium functional groups are both positively charged, and can adsorb negatively charged clay, neutralize the negative charge, reduce the repulsion between clay crystal layers, and play an anti-swelling role. In particular, the linear polyether functional group of the present invention has a positively charged ammonium salt at the end, which can enter deep into the clay cavity and combine with the clay very firmly. The main chain is a hydrophobic polymer alkyl chain, which can prevent water molecules from contacting the clay and inhibit expansion. The present invention has a large amount of positive charge and can form multi-point adsorption with multiple clay particles at the same time. After adsorption, a layer of polymer protective film is formed on the surface of the clay particles to protect the clay particles and prevent the clay particles from hydration, expansion, and migration.

[0034] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0035] (1) The oil field clay stabilizer of the present invention has low raw material price, wide source and simple preparation process;

[0036] (2) The oilfield clay stabilizer of the present invention has the advantages of high anti-swelling rate and low mudstone loss rate. The anti-swelling rate reaches 96% or more, and the mudstone loss rate is less than 7%. DETAILED DESCRIPTION

[0037] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0038] The present invention will be further described below with reference to specific embodiments.

[0039] Example 1

[0040] (1) Add 0.1 mol of trimethylolpropane allyl ether and 3.48 g of potassium hydroxide to a high-pressure reactor, purge the pipeline and the reactor with nitrogen, evacuate, purge the pipeline and the reactor with nitrogen again, then slowly heat to 86°C, evacuate again, and introduce 0.4 mol of ethylene oxide. After the introduction is complete, keep the reaction at 120°C, and the pressure gradually decreases. When the pressure stabilizes, stop the reaction and cool the system to below 40°C.

[0041] (2) Add 0.25 mol of aminosulfonic acid powder to the above autoclave, keep the reaction at 110°C for 2 h, add 174 g of distilled water, and adjust the pH to 7-8 with potassium hydroxide.

[0042] (3) The mixed solution was transferred to a normal pressure reactor, and 0.1 mol (3-acrylamidopropyl) trimethylammonium chloride and 1.74 g disodium hydrogen phosphate were added and stirred evenly. 1.74 g initiator was added dropwise to the reactor, and the initiator was a mixed solution of sodium persulfate and sodium bisulfite, wherein the concentration of sodium persulfate was 12 wt % and the concentration of sodium bisulfite was 4 wt %. After the addition was completed, the mixture was stirred and reacted until the solution began to become viscous, and the temperature was raised to 80° C. The mixture was kept warm for 2 h to obtain a viscous mixed solution, and the temperature was lowered to below 40° C. The pH was adjusted to 7-8 with potassium hydroxide.

[0043] (4) The viscous mixed liquid is dried and granulated to obtain clay stabilizer A1.

[0044] Example 2

[0045] (1) Add 0.1 mol of trimethylolpropane allyl ether and 4.27 g of potassium hydroxide to a high-pressure reactor, purge the pipeline and the reactor with nitrogen, evacuate, purge the pipeline and the reactor with nitrogen again, then slowly heat to 85° C., evacuate again, and introduce 0.8 mol of ethylene oxide. After the introduction is complete, keep the reaction at 130° C., and the pressure gradually decreases. When the pressure stabilizes, stop the reaction and cool the system to below 40° C.

[0046] (2) Add 0.3 mol of aminosulfonic acid powder to the above autoclave, keep the reaction at 120°C for 1 hour, add 268 g of distilled water, and adjust the pH to 7-8 with potassium hydroxide.

[0047] (3) The mixed solution was transferred to a normal pressure reactor, and 0.09 mol (3-acrylamidopropyl) trimethylammonium chloride and 2.34 g disodium hydrogen phosphate were added and stirred evenly. 2.88 g initiator was added dropwise to the reactor, and the initiator was a mixed solution of sodium persulfate and potassium bisulfite, wherein the concentration of sodium persulfate was 12 wt % and the concentration of potassium bisulfite was 5 wt %. After the addition was completed, the mixture was stirred and reacted until the solution began to become viscous, and the temperature was raised to 80° C. The reaction was continued at this temperature for 1 h to obtain a viscous mixed solution, and the temperature was lowered to below 40° C. and the pH was adjusted to 7-8 with potassium hydroxide.

[0048] (4) The viscous mixed liquid is dried and granulated to obtain clay stabilizer A2.

[0049] Example 3

[0050] (1) Add 0.1 mol of trimethylolpropane allyl ether and 5.33 g of potassium hydroxide to a high-pressure reactor, purge the pipeline and the reactor with nitrogen, evacuate, purge the pipeline and the reactor with nitrogen again, then slowly heat to 90° C., evacuate again, and introduce 1.5 mol of ethylene oxide. After the introduction is complete, keep the reaction at 140° C., and the pressure gradually decreases. When the pressure stabilizes, stop the reaction and cool the system to below 40° C.

[0051] (2) Add 0.3 mol of aminosulfonic acid powder to the above autoclave, keep the reaction at 130°C for 1.5 h, add 314 g of distilled water, and adjust the pH to 7-8 with potassium hydroxide.

[0052] (3) The mixed solution was transferred to a normal pressure reactor, and 0.08 mol (3-acrylamidopropyl) trimethylammonium chloride and 3.88 g potassium dihydrogen phosphate were added and stirred evenly. 3.74 g initiator was added dropwise to the reactor, and the initiator was a mixed solution of potassium persulfate and sodium bisulfite, wherein the concentration of potassium persulfate was 11 wt % and the concentration of sodium bisulfite was 3 wt %. After the addition was completed, the mixture was stirred and reacted until the solution began to become viscous, and the temperature was raised to 80° C. The reaction was continued at this temperature for 1.5 h to obtain a viscous mixed solution, and the temperature was lowered to below 40° C. and the pH was adjusted to 7-8 with potassium hydroxide.

[0053] (4) The viscous mixed liquid is dried and granulated to obtain clay stabilizer A3.

[0054] Example 4

[0055] (1) Add 0.1 mol of trimethylolpropane allyl ether and 5.88 g of potassium hydroxide to a high-pressure reactor, purge the pipeline and the reactor with nitrogen, evacuate, purge the pipeline and the reactor with nitrogen again, then slowly heat to 90° C., evacuate again, and introduce 2 mol of ethylene oxide. After the introduction is complete, keep the reaction at 150° C., and the pressure gradually decreases. When the pressure stabilizes, stop the reaction and cool the system to below 40° C.

[0056] (2) Add 0.4 mol of aminosulfonic acid powder to the above autoclave, keep the reaction at 125°C for 2 h, add 444 g of distilled water, and adjust the pH to 7-8 with potassium hydroxide.

[0057] (3) The mixed solution was transferred to a normal pressure reactor, and 0.07 mol (3-acrylamidopropyl) trimethylammonium chloride and 4.74 g potassium dihydrogen phosphate were added and stirred evenly. 5.55 g initiator was added dropwise to the reactor, and the initiator was a mixed solution of potassium persulfate and potassium bisulfite, wherein the concentration of potassium persulfate was 11 wt % and the concentration of potassium bisulfite was 4 wt %. After the addition was completed, the mixture was stirred and reacted until the solution began to become viscous, and the temperature was raised to 80° C. The mixture was kept warm for 2 h to obtain a viscous mixed solution, and the temperature was lowered to below 40° C. The pH was adjusted to 7-8 with potassium hydroxide.

[0058] (4) The viscous mixed liquid is dried and granulated to obtain clay stabilizer A4.

[0059] Example 5

[0060] (1) Add 0.1 mol of trimethylolpropane allyl ether and 6.48 g of potassium hydroxide to a high-pressure reactor, purge the pipeline and the reactor with nitrogen, evacuate, purge the pipeline and the reactor with nitrogen again, then slowly heat to 88° C., evacuate again, and introduce 3 mol of ethylene oxide. After the introduction is complete, keep the reaction at 160° C., and the pressure gradually decreases. When the pressure stabilizes, stop the reaction and cool the system to below 40° C.

[0061] (2) Add 0.35 mol of aminosulfonic acid powder to the above autoclave, keep the reaction at 120°C for 1.5 h, add 474 g of distilled water, and adjust the pH to 7-8 with potassium hydroxide.

[0062] (3) The mixed solution was transferred to a normal pressure reactor, and 0.06 mol (3-acrylamidopropyl) trimethylammonium chloride and 5.22 g diammonium hydrogen phosphate were added and stirred evenly. 7.98 g initiator was added dropwise to the reactor, and the initiator was a mixed solution of ammonium persulfate and potassium bisulfite, wherein the concentration of ammonium persulfate was 10 wt % and the concentration of potassium bisulfite was 3 wt %. After the addition was completed, the mixture was stirred and reacted until the solution began to become viscous, and the temperature was raised to 80°C, and the reaction was continued at this temperature for 2 h to obtain a viscous mixed solution, and the temperature was lowered to below 40°C, and the pH was adjusted to 7-8 with potassium hydroxide.

[0063] (4) The viscous mixed liquid is dried and granulated to obtain clay stabilizer A5.

[0064] Example 6

[0065] (1) Add 0.1 mol of trimethylolpropane allyl ether and 6.96 g of potassium hydroxide to a high-pressure reactor, purge the pipeline and the reactor with nitrogen, evacuate, purge the pipeline and the reactor with nitrogen again, then slowly heat to 87°C, evacuate again, and introduce 4 mol of ethylene oxide. After the introduction is complete, react at 170°C while keeping the temperature to react. The pressure gradually decreases. When the pressure stabilizes, stop the reaction and cool the system to below 40°C.

[0066] (2) Add 0.4 mol of aminosulfonic acid powder to the above autoclave, keep the reaction at 130°C for 2 h, add 522 g of distilled water, and adjust the pH to 7-8 with potassium hydroxide.

[0067] (3) The mixed solution was transferred to a normal pressure reactor, and 0.05 mol (3-acrylamidopropyl) trimethylammonium chloride and 4.23 g diammonium hydrogen phosphate were added and stirred evenly. 8.7 g initiator was added dropwise to the reactor, and the initiator was a mixed solution of ammonium persulfate and potassium bisulfite, wherein the concentration of ammonium persulfate was 10 wt % and the concentration of potassium bisulfite was 4 wt %. After the addition was completed, the mixture was stirred and reacted until the solution began to become viscous, and the temperature was raised to 80° C. The reaction was continued at this temperature for 1.8 h to obtain a viscous mixed solution, and the temperature was lowered to below 40° C. and the pH was adjusted to 7-8 with potassium hydroxide.

[0068] (4) The viscous mixed liquid is dried and granulated to obtain clay stabilizer A6.

[0069] Example 7 Evaluation of the Anti-swelling Capacity of Clay Stabilizer

[0070] The heat-resistant clay stabilizer (A1-A6) of the present invention was prepared into a solution with a concentration of 1 wt % with distilled water, and the anti-swelling rate was tested by the centrifugation method with reference to SY / T5971-2016 "Performance Evaluation Method of Clay Stabilizer for Oil and Gas Field Fracturing Acidification and Water Injection".

[0071] The clay stabilizer of Huainan Kedi Chemical Technology Co., Ltd. was used as a comparative sample, and the test results are shown in Table 1.

[0072] It can be seen from Table 1 that the clay stabilizer for oil field (A1-A6) of the present invention has the characteristic of high anti-swelling rate. When the use concentration is 1wt%, the anti-swelling rate reaches 96% or above, and the highest reaches 99% (Example 6); while the anti-swelling rate of the comparative sample is 91%, which is significantly lower than that of the present invention.

[0073] Example 8 Determination of mudstone loss rate of clay stabilizer

[0074] The heat-resistant clay stabilizer (A1-A6) of the present invention was prepared into a 1 wt% solution with distilled water, and the mudstone loss rate was tested with reference to SY / T5971-2016 "Performance Evaluation Method of Clay Stabilizer for Oil and Gas Field Fracturing Acidification and Water Injection", and the test temperature was 90°C.

[0075] The clay stabilizer of Huainan Kedi Chemical Technology Co., Ltd. was used as a comparative sample, and the test results are shown in Table 1.

[0076] Table 1 Test results of anti-swelling rate and mudstone loss rate

[0077] Clay stabilizer Anti-swelling rate, % Mudstone loss rate, % <![CDATA[A1]]> 96 6.8 <![CDATA[A2]]> 96.5 6.4 <![CDATA[A3]]> 97.4 5.5 <![CDATA[A4]]> 98 4.9 <![CDATA[A5]]> 98.6 4.5 <![CDATA[A6]]> 99 4.2 Comparative Example 91 14.9

[0078] It can be seen from Table 1 that the clay stabilizer for oil field (A1-A6) of the present invention has the characteristic of low mudstone loss rate. When the use concentration is 1wt% and the temperature is 90°C, the mudstone loss rate is lower than 7%, and the lowest is 4.2% (Example 6); while the mudstone loss rate of the comparative sample is 14.9%, which is significantly higher than that of the present invention.

[0079] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0080] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0081] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for preparing a clay stabilizer for oil fields, characterized in that: The specific steps of the preparation method are as follows: (1) Add trimethylolpropane allyl ether and potassium hydroxide to a high-pressure reactor, purge the pipeline and the reactor with nitrogen, evacuate, purge the pipeline and the reactor with nitrogen again, then slowly heat to 85-90° C., evacuate again, and introduce ethylene oxide. After the introduction is complete, keep the temperature to react, and the pressure gradually decreases. When the pressure stabilizes, stop the reaction and cool the system to below 40° C.; (2) Add sulfamic acid powder to the above autoclave, heat at 110-130° C. for 1-2 hours, add distilled water, and adjust the pH to 7-8 with potassium hydroxide; (3) The mixed solution is transferred to a normal pressure reactor, (3-acrylamidopropyl)trimethylammonium chloride and buffer salt are added, and stirred evenly; the initiator is added dropwise to the reactor, and after the addition is completed, the reaction is stirred until the solution begins to become viscous, and the temperature is raised to 80° C. and the reaction is continued at this temperature for 1-2 hours to obtain a viscous mixed solution, and the temperature is lowered to below 40° C. and the pH is adjusted to 7-8 with potassium hydroxide; (4) drying and granulating the viscous mixed liquid to obtain a clay stabilizer; Based on 1 mole of trimethylolpropane allyl ether, the amounts of ethylene oxide, aminosulfonic acid, and (3-acrylamidopropyl)trimethylammonium chloride are 4-40 mole parts, 2.5-4 mole parts, and 0.5-1 mole parts, respectively; The molecular structure of the clay stabilizer is as follows: Wherein, x = 100-1000; y＝50-1000； n＝2-20。 2. The method for preparing a clay stabilizer for oil fields as claimed in claim 1, characterized in that: In step (1), the mass ratio of potassium hydroxide to trimethylolpropane allyl ether is 0.2-0.4:

1.

3. The method for preparing a clay stabilizer for oil fields as claimed in claim 1, characterized in that: In step (1), the insulation reaction temperature is 120-170°C.

4. The method for preparing a clay stabilizer for oil fields as claimed in claim 1, characterized in that: In step (2), the mass ratio of distilled water to trimethylolpropane allyl ether is 10-30:

1.

5. The method for preparing a clay stabilizer for oil fields as claimed in claim 1, characterized in that: In step (3), the buffer salt is one of disodium hydrogen phosphate, dipotassium hydrogen phosphate, and diammonium hydrogen phosphate, and the weight ratio of the buffer salt to trimethylolpropane allyl ether is 0.1-0.3:

1.

6. The method for preparing a clay stabilizer for oil fields as claimed in claim 5, characterized in that: The buffer salt is one of dipotassium hydrogen phosphate and diammonium hydrogen phosphate.

7. The method for preparing a clay stabilizer for oil fields as claimed in claim 1, characterized in that: In step (3), the initiator is a mixed solution of persulfate and bisulfite, wherein the concentration of persulfate is 8-12wt%, the concentration of bisulfite is 3-5wt%, and the weight ratio of the initiator to trimethylolpropane allyl ether is 0.1-0.5:

1.

8. The method for preparing a clay stabilizer for oil fields as claimed in claim 7, characterized in that: The persulfate is one of sodium persulfate, potassium persulfate and ammonium persulfate. The bisulfite is sodium bisulfite or potassium bisulfite.

9. The clay stabilizer prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The molecular structure of the clay stabilizer is as follows: Wherein, x = 100-1000; y＝50-1000； n＝2-20。 10. Use of the oilfield clay stabilizer as claimed in claim 9 in the development of oil and gas fields.

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