Temperature-resistant clay stabilizer as well as synthesis method and application thereof

Abstract

The invention belongs to the technical field of oil exploitation and relates to a temperature-resistant clay stabilizer as well as a synthesis method and application thereof. The synthesis method comprises the following steps: adding 2, 2-bis (allyloxymethyl)-1-butanol and sulfamic acid into a reactor, heating, naturally cooling to below 50 DEG C, and stirring for dissolving; adding 1-vinyl-3-ethylimidazolium bromide, 2-methacryloyloxyethyl phosphorylcholine and buffer salt, uniformly stirring, and adjusting the pH value to be 7-8; dropwise adding an initiator, carrying out a stirring reaction, heating, continuously carrying out a heat preservation reaction to obtain a viscous mixed solution, 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 wide in raw material source, simple in preparation process and free of byproducts; meanwhile, the anti-swelling agent has the advantages of high anti-swelling rate, washing resistance and low mudstone loss rate.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum exploitation and relates to a temperature-resistant clay stabilizer and a synthesis method and application thereof. Background Art

[0002] During the development of oil fields, there are a large number of clay minerals in the formation, such as kaolinite, montmorillonite, illite and chlorite. When encountering external water or water-based substances, these clay minerals will swell, disperse and migrate, and then block the pore throats, resulting in a decrease in formation permeability, affecting the flow of oil and gas in the formation, and then damaging the oil and gas reservoir, affecting the extraction efficiency and output of the oil field.

[0003] In oilfield process measures such as drilling, cementing, water injection, fracturing, acidizing, workover and well killing, water-based working fluids are inevitably used, which can easily cause water-sensitive damage. Therefore, adding clay stabilizers in these processes is an effective means to protect water-sensitive formations.

[0004] Clay stabilizers are generally positively charged, and the cations and negative ions on the surface of the clay crystal layer are combined to form an anti-swelling system, thereby forming a hydrophobic protective film on the clay surface, isolating the attraction of the dipole of the oxygen bond or the amino oxygen bond of the clay crystal layer to water molecules, thus preventing the clay from hydrating and swelling. At the same time, an inter-ionic repulsive force is generated in the hydrated clay system, which plays a role in polymerization and condensation, causing the clay particles to aggregate into clay particles, and ultimately preventing the dispersion and migration of clay.

[0005] CN114106795A discloses a clay stabilizer and its preparation method and application, belonging to the technical field of clay stabilizers. The clay stabilizer, by weight, comprises: 2-8 parts of bisindolylmethane compounds, 2-8 parts of quinazolinone compounds, 5-15 parts of methanol and 80-85 parts of water. The clay stabilizer has a small molecular weight, which is conducive to dispersion on the clay surface, has high anti-swelling efficiency, and is easy to discharge. After fracturing or mining operations, it can reduce residues and reduce damage to the formation. The invention belongs to non-ionic organic matter, has poor adsorption on negatively charged clay, and has limited effect in preventing clay hydration, swelling and migration.

[0006] CN104098738B discloses a method for preparing a low molecular weight polymer clay stabilizer, wherein the clay stabilizer is prepared by polymerization in an aqueous solution using carbon-containing ammonium salt and 2-acrylamide-2-methylpropanesulfonic acid (AMPS) as raw materials in the presence of an initiator, and the polymer number average molecular weight is less than 50,000. Sulfonic acid groups are introduced into the polymer stabilizer to increase the water solubility and temperature resistance of the polymer. It can simultaneously form multi-point adsorption with multiple clay particles in water, and after adsorption, a layer of adsorption protective film is formed on the surface of the clay particles to prevent the expansion and migration of the clay particles; however, it has poor temperature resistance, which limits its application range. Summary of the invention

[0007] The present invention aims to provide a temperature-resistant clay stabilizer and its synthesis method and application in view of the above-mentioned deficiencies in the prior art. The clay stabilizer of the present invention has a wide source of raw materials, a simple preparation process, and no by-products; it also has the advantages of high anti-swelling rate, water washing resistance, and low mudstone loss rate.

[0008] In order to achieve the above objectives:

[0009] In a first aspect, the present invention discloses a temperature-resistant clay stabilizer, the molecular structure of the clay stabilizer is as follows:

[0010]

[0011] Wherein, m = 100-1000;

[0012] n = 50-1000;

[0013] p = 50-1000;

[0014] x = 100-1000;

[0015] y = 50-1000;

[0016] z=50-1000.

[0017] Preferably, the viscosity average molecular weight of the clay stabilizer is 200,000-1,000,000.

[0018] In another aspect, the present invention discloses a method for synthesizing the above-mentioned clay stabilizer, and the specific steps of the synthesis method are as follows:

[0019] (1) Add 2,2-bis(allyloxymethyl)-1-butanol and aminosulfonic acid into a reactor, purge the reactor and pipeline with nitrogen, ensure that the reactor is filled with nitrogen in the later stage of synthesis, heat to 110-120° C., maintain for 1-2 hours, cool naturally to below 50° C., add distilled water, and stir to dissolve;

[0020] (2) adding 1-vinyl-3-ethylimidazolium bromide, 2-methacryloyloxyethyl phosphorylcholine and buffer salt to the above reactor, stirring evenly, and adjusting the pH to 7-8 with potassium hydroxide solution;

[0021] (3) Add the initiator dropwise to the reactor. After the addition is complete, stir the reaction until the solution begins to become viscous. Raise the temperature to 70°C and continue the reaction for 1-2 hours to obtain a viscous mixed solution. Lower the temperature to below 40°C and adjust the pH to 7-8 with aqueous ammonia.

[0022] (4) drying and granulating the viscous mixed liquid to obtain a clay stabilizer.

[0023] In the present invention, preferably, based on 1 mol part of 2,2-bis(allyloxymethyl)-1-butanol, the amounts of aminosulfonic acid, 1-vinyl-3-ethylimidazolium bromide, and 2-methacryloyloxyethyl phosphorylcholine are 0.8-1.2 mol parts, 1-2 mol parts, and 1-2 mol parts, respectively.

[0024] In the present invention, preferably, the weight ratio of distilled water to 2,2-bis(allyloxymethyl)-1-butanol in step (1) is 12-15:1.

[0025] In the present invention, preferably, the buffer salt described in step (2) 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 2,2-bis(allyloxymethyl)-1-butanol is 0.1-0.2:1.

[0026] In the present invention, preferably, the initiator described in step (3) 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 2,2-bis(allyloxymethyl)-1-butanol is 0.1-0.4:1.

[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 heat-resistant clay stabilizer synthesis reaction equation 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 heat-resistant clay stabilizer of the present invention is a high molecular polymer. The ammonium root, imidazole and quaternary ammonium functional groups all carry positive charges, can adsorb negatively charged clay, neutralize the negative charges, reduce the repulsion between clay crystal layers, and play an anti-swelling role; the diameter of the potassium ion introduced in the preparation process of the present invention is 266pm, and the radius of the ammonium ion is 286pm, which is very close to the structural pore of the clay 280pm, is easy to enter the pore space and is not easy to release, and is firmly combined; the phosphate group is a hydrophilic group, which can be combined with water in the cavity; the main chain is a hydrophobic polymerized alkyl chain, which can prevent water molecules from contacting with clay and inhibit expansion; the present invention carries a large amount of positive charges, can form multi-point adsorption with multiple clay particles at the same time, and 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 hydration, expansion and migration of the clay particles.

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

[0035] (1) The raw material sources of the heat-resistant clay stabilizer of the present invention are wide, the preparation process is simple, the synthesis method is a one-pot process, and there are no by-products;

[0036] (2) The heat-resistant clay stabilizer of the present invention has the advantage of high anti-swelling rate, reaching 97.5% or more;

[0037] (3) The heat-resistant clay stabilizer of the present invention has the advantage of good temperature resistance, reaching 320°C and above;

[0038] (4) The heat-resistant clay stabilizer of the present invention has the advantage of low mudstone loss rate, which is no more than 7%. DETAILED DESCRIPTION

[0039] 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.

[0040] The present invention will be further described below in conjunction with specific embodiments:

[0041] Example 1

[0042] (1) Add 0.05 mol of 2,2-bis(allyloxymethyl)-1-butanol and 0.04 mol of aminosulfonic acid into a reactor, purge the reactor and pipeline with nitrogen, and ensure that the reactor is filled with nitrogen in the later synthesis. Heat to 110° C., maintain for 1 hour, cool naturally to below 50° C., add 128.4 g of distilled water, and stir to dissolve;

[0043] (2) Add 0.05 mol of 1-vinyl-3-ethylimidazolium bromide, 0.05 mol of 2-methacryloyloxyethyl phosphorylcholine, and 1.07 g of disodium hydrogen phosphate into the above reactor, stir evenly, and adjust the pH to 7-8 with potassium hydroxide solution;

[0044] (3) 1.07 g of an initiator was added dropwise to the reactor. The initiator was a mixture of sodium persulfate and sodium bisulfite, wherein the concentration of sodium persulfate was 12 wt % and the concentration of sodium bisulfite was 5 wt %. After the addition was completed, the mixture was stirred and reacted until the solution began to become viscous. The mixture was heated to 70° C. and kept warm for 1 h to obtain a viscous mixed solution. The mixture was cooled to below 40° C. and the pH was adjusted to 7-8 with aqueous ammonia.

[0045] (4) The viscous mixed liquid is dried and granulated to obtain clay stabilizer B1.

[0046] Example 2

[0047] (1) Add 0.05 mol of 2,2-bis(allyloxymethyl)-1-butanol and 0.042 mol of aminosulfonic acid into a reactor, purge the reactor and pipeline with nitrogen, and ensure that the reactor is filled with nitrogen in the later synthesis. Heat to 115° C., maintain for 1.5 h, cool naturally to below 50° C., add 141.3 g of distilled water, and stir to dissolve;

[0048] (2) Add 0.07 mol of 1-vinyl-3-ethylimidazolium bromide, 0.08 mol of 2-methacryloyloxyethyl phosphorylcholine, and 1.48 g of disodium hydrogen phosphate into the above reactor, stir evenly, and adjust the pH to 7-8 with potassium hydroxide solution;

[0049] (3) 1.98 g of an initiator was added dropwise to the reactor. The initiator was a mixture of sodium persulfate and potassium bisulfite, wherein the concentration of sodium persulfate was 12 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. The mixture was heated to 70° C. and kept warm for 1.5 h to obtain a viscous mixed solution. The mixture was cooled to below 40° C. and the pH was adjusted to 7-8 with aqueous ammonia.

[0050] (4) The viscous mixed liquid is dried and granulated to obtain clay stabilizer B2.

[0051] Example 3

[0052] (1) Add 0.05 mol of 2,2-bis(allyloxymethyl)-1-butanol and 0.06 mol of aminosulfonic acid into a reactor, purge the reactor and pipeline with nitrogen, and ensure that the reactor is filled with nitrogen in the later synthesis. Heat to 120° C., maintain for 1 hour, cool naturally to below 50° C., add 158.6 g of distilled water, and stir to dissolve;

[0053] (2) Add 0.1 mol of 1-vinyl-3-ethylimidazolium bromide, 0.07 mol of 2-methacryloyloxyethyl phosphorylcholine, and 1.98 g of dipotassium hydrogen phosphate to the above reactor, stir evenly, and adjust the pH to 7-8 with potassium hydroxide solution;

[0054] (3) 2.37 g of initiator was added dropwise to the reactor. The initiator was a mixture of potassium persulfate and sodium bisulfite, wherein the concentration of potassium persulfate was 11 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. The mixture was heated to 70° C. and kept warm for 2 h to obtain a viscous mixed solution. The mixture was cooled to below 40° C. and the pH was adjusted to 7-8 with aqueous ammonia.

[0055] (4) The viscous mixed liquid is dried and granulated to obtain clay stabilizer B3.

[0056] Example 4

[0057] (1) Add 0.05 mol of 2,2-bis(allyloxymethyl)-1-butanol and 0.048 mol of aminosulfonic acid into a reactor, purge the reactor and pipeline with nitrogen, and ensure that the reactor is filled with nitrogen in the later synthesis. Heat to 118° C., maintain for 1.5 h, cool naturally to below 50° C., add 133.4 g of distilled water, and stir to dissolve;

[0058] (2) Add 0.06 mol of 1-vinyl-3-ethylimidazolium bromide, 0.08 mol of 2-methacryloyloxyethyl phosphorylcholine, and 1.88 g of dipotassium hydrogen phosphate into the above reactor, stir evenly, and adjust the pH to 7-8 with potassium hydroxide solution;

[0059] (3) 3.66 g of initiator was added dropwise to the reactor. The initiator was a mixture of potassium persulfate and potassium bisulfite, wherein the concentration of potassium 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. The mixture was heated to 70° C. and kept warm for 1 h to obtain a viscous mixed solution. The mixture was cooled to below 40° C. and the pH was adjusted to 7-8 with aqueous ammonia.

[0060] (4) The viscous mixed liquid is dried and granulated to obtain clay stabilizer B4.

[0061] Example 5

[0062] (1) Add 0.05 mol of 2,2-bis(allyloxymethyl)-1-butanol and 0.055 mol of aminosulfonic acid into a reactor, purge the reactor and pipeline with nitrogen, and ensure that the reactor is filled with nitrogen in the later synthesis. Heat to 116° C., maintain for 1.8 h, cool naturally to below 50° C., add 160.4 g of distilled water, and stir to dissolve;

[0063] (2) Add 0.08 mol of 1-vinyl-3-ethylimidazolium bromide, 0.1 mol of 2-methacryloyloxyethyl phosphorylcholine, and 2.14 g of diammonium hydrogen phosphate into the above reactor, stir evenly, and adjust the pH to 7-8 with potassium hydroxide solution;

[0064] (3) 4.28 g of initiator was added dropwise to the reactor. The initiator was a mixture of ammonium persulfate and potassium bisulfite, wherein the concentration of ammonium persulfate was 8 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. The mixture was heated to 70° C. and kept warm for 1.2 h to obtain a viscous mixed solution. The mixture was cooled to below 40° C. and the pH was adjusted to 7-8 with aqueous ammonia.

[0065] (4) The viscous mixed liquid is dried and granulated to obtain clay stabilizer B5.

[0066] Example 6

[0067] (1) Add 0.05 mol of 2,2-bis(allyloxymethyl)-1-butanol and 0.05 mol of aminosulfonic acid into a reactor, purge the reactor and pipeline with nitrogen, and ensure that the reactor is filled with nitrogen in the later synthesis. Heat to 115° C., maintain for 2 h, cool naturally to below 50° C., add 156 g of distilled water, and stir to dissolve;

[0068] (2) Add 0.09 mol of 1-vinyl-3-ethylimidazolium bromide, 0.07 mol of 2-methacryloyloxyethyl phosphorylcholine, and 2.07 g of diammonium hydrogen phosphate into the above reactor, stir evenly, and adjust the pH to 7-8 with potassium hydroxide solution;

[0069] (3) 3.14 g of initiator was added dropwise to the reactor. The initiator was a mixture 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. The mixture was heated to 70° C. and kept warm for 2 h to obtain a viscous mixed solution. The mixture was cooled to below 40° C. and the pH was adjusted to 7-8 with aqueous ammonia.

[0070] (4) The viscous mixed liquid is dried and granulated to obtain clay stabilizer B6.

[0071] Example 7 Evaluation of the Anti-swelling Capacity of Clay Stabilizer

[0072] The heat-resistant clay stabilizer (B1-B6) 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".

[0073] A comparative experiment was conducted using the clay stabilizer HJZ-500 produced by Kaifeng Hengju Biotechnology Co., Ltd. The test results are shown in Table 1.

[0074] It can be seen from Table 1 that the heat-resistant clay stabilizer (B1-B6) of the present invention has the advantage of a high anti-swelling rate. When the use concentration is 1wt%, the anti-swelling rate reaches 97.5% or more, and the highest is 98.6% (Example 6); while the anti-swelling rate of the comparative example Kaifeng Hengju Biotechnology Co., Ltd. fracturing clay stabilizer HJZ-500 is 91.2%, which is significantly lower than that of the present invention.

[0075] Example 8 Evaluation of the heat resistance of clay stabilizers

[0076] The heat-resistant clay stabilizer (B1-B6) of the present invention was prepared into a 1 wt% solution with distilled water, and the clay stabilizer solution was sealed and placed in a thermostatic box set at different temperatures and taken out after 24 hours. The anti-swelling rate was tested according to the method of Example 7.

[0077] As the temperature rises, the anti-swelling rate gradually decreases. When the anti-swelling rate drops to 85%, the corresponding temperature is the temperature resistance of the clay stabilizer.

[0078] A comparative experiment was conducted using the clay stabilizer HJZ-500 produced by Kaifeng Hengju Biotechnology Co., Ltd. The test results are shown in Table 1.

[0079] It can be seen from Table 1 that the heat-resistant clay stabilizer (B1-B6) of the present invention has the advantage of good temperature resistance. When the use concentration is 1wt%, the temperature resistance reaches 320°C and above, and the highest reaches 340°C; while the temperature resistance of the clay stabilizer HJZ-500 for fracturing produced by Kaifeng Hengju Biotechnology Co., Ltd. is 250°C, which is significantly lower than that of the present invention.

[0080] Example 9 Determination of mudstone loss rate of clay stabilizer

[0081] The heat-resistant clay stabilizer (B1-B6) 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.

[0082] A comparative experiment was conducted using the clay stabilizer HJZ-500 produced by Kaifeng Hengju Biotechnology Co., Ltd. The test results are shown in Table 1.

[0083] Table 1 Test results of anti-swelling rate, temperature resistance and mudstone loss rate

[0084] Clay stabilizer Anti-swelling rate, % Temperature resistance, ℃ Mudstone loss rate, % <![CDATA[B1]]> 97.5 320 7 <![CDATA[B2]]> 98 330 6.4 <![CDATA[B3]]> 97.5 340 6.7 <![CDATA[B4]]> 98.5 330 6 <![CDATA[B5]]> 98.2 340 6.3 <![CDATA[B6]]> 98.6 340 6 Comparative Example 91.2 250 15.6

[0085] It can be seen from Table 1 that the temperature-resistant clay stabilizer (B1-B6) of the present invention has the advantage of low mudstone loss rate. When the use concentration is 1wt% and the temperature is 90°C, the mudstone loss rate is not higher than 7%, and the lowest is 6%. The mudstone loss rate of the comparative clay stabilizer HJZ-500 for fracturing produced by Kaifeng Hengju Biotechnology Co., Ltd. is 15.6%, which is significantly higher than that of the present invention.

[0086] 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.

[0087] 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.

[0088] 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 synthesizing a temperature-resistant clay stabilizer, characterized in that: The specific steps of the synthetic method are as follows: (1) Add 2,2-bis(allyloxymethyl)-1-butanol and aminosulfonic acid into a reactor, purge the reactor and pipeline with nitrogen, ensure that the reactor is filled with nitrogen in the later stage of synthesis, heat to 110-120° C., maintain for 1-2 hours, cool naturally to below 50° C., add distilled water, and stir to dissolve; (2) adding 1-vinyl-3-ethylimidazolium bromide, 2-methacryloyloxyethyl phosphorylcholine and buffer salt to the above reactor, stirring evenly, and adjusting the pH to 7-8 with potassium hydroxide solution; (3) Add the initiator dropwise to the reactor. After the addition is complete, stir the reaction until the solution begins to become viscous. Raise the temperature to 70°C and continue the reaction for 1-2 hours to obtain a viscous mixed solution. Lower the temperature to below 40°C and adjust the pH to 7-8 with aqueous ammonia. (4) drying and granulating the viscous mixed liquid to obtain a clay stabilizer; Based on 1 mol of 2,2-bis(allyloxymethyl)-1-butanol, the amounts of aminosulfonic acid, 1-vinyl-3-ethylimidazolium bromide, and 2-methacryloyloxyethyl phosphorylcholine are 0.8-1.2 mol, 1-2 mol, and 1-2 mol, respectively; The molecular structure of the clay stabilizer is as follows: Wherein, m = 100-1000; n＝50-1000； p＝50-1000； x＝100-1000； y＝50-1000； z＝50-1000。 2. The synthesis method according to claim 1, characterized in that The weight ratio of distilled water to 2,2-bis(allyloxymethyl)-1-butanol in step (1) is 12-15:

1.

3. The synthesis method according to claim 1, characterized in that The buffer salt described in step (2) is one of disodium hydrogen phosphate, dipotassium hydrogen phosphate, and diammonium hydrogen phosphate, and the weight ratio of the buffer salt to 2,2-bis(allyloxymethyl)-1-butanol is 0.1-0.2:

1.

4. The synthesis method according to claim 3, characterized in that The buffer salt is one of dipotassium hydrogen phosphate and diammonium hydrogen phosphate.

5. The synthesis method according to claim 1, characterized in that The initiator described in step (3) is a mixed solution of persulfate and bisulfite, and the weight ratio of the initiator to 2,2-bis(allyloxymethyl)-1-butanol is 0.1-0.4:

1.

6. The synthesis method according to claim 5, characterized in that The concentration of the persulfate is 8-12 wt %, and the concentration of the bisulfite is 3-5 wt %.

7. The synthesis method according to claim 5, characterized in that The persulfate is one of sodium persulfate, potassium persulfate and ammonium persulfate.

8. The synthesis method according to claim 5, characterized in that The bisulfite is sodium bisulfite or potassium bisulfite.

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

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