Preparation method of water-based polymer fracturing fluid thickening agent with high salt resistance

Abstract

The invention relates to a preparation method of a high-salt-resistance water-based polymer fracturing fluid thickening agent, and relates to the technical field of petroleum additives. The thickening agent comprises the following components in percentage by weight: 3.5 to 4.2 percent of a surfactant, 0.7 to 0.9 percent of a stabilizer, 1.3 to 1.8 percent of a cross-linking agent and the balance of a polymer thickening agent, according to the polymer thickener, based on addition reaction of saturated monomers, a synergistic structure of a side-chain-alternating amphipathic ion structure and a flexible long alkyl alcohol chain is constructed, and due to the internal electrostatic interaction which is not obviously interfered by external salt ions, a polymer can still keep stable thickening capacity in a high-temperature and high-salt environment; long alkyl alcohol chains are interwoven and wound in a water-based environment by virtue of the hydrophobic effect of the long alkyl alcohol chains to form dynamic and reversible physical cross-linking points, so that the polymer thickening agent shows the pseudoplastic characteristic, and the thickening agent can intelligently adapt to the requirements of different stages of fracturing construction.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of petroleum aids, and particularly relates to a preparation method of a high-salt-water-resistance polymer fracturing fluid thickening agent. BACKGROUND

[0002] Hydraulic fracturing technology is a core stimulation means for modern oil and gas fields, especially unconventional oil and gas resource development, and its effectiveness depends on the performance of the fracturing fluid system to a great extent. As a key component of the fracturing fluid system, the core function of the thickening agent is to greatly improve the viscosity of the water phase, thereby endowing the fracturing fluid with two important abilities: one is to efficiently suspend and transport proppants to the deep part of the formation fracture to form an oil and gas seepage channel with high conductivity; the other is to quickly form a low-permeability filter cake on the fracture wall to effectively control the filtration of the fracturing fluid to the formation, improve the fracturing efficiency and reduce the damage to the reservoir. With the global oil and gas exploration and development constantly moving towards deep and ultra-deep layers and high salinity reservoirs, the fracturing fluid thickening agent is facing severe tests in extreme environments of high temperature and high salt, and its performance directly determines the success or failure of fracturing construction and economic benefits.

[0003] For a long time, the field of fracturing fluid thickening agents has been mainly dominated by natural biological gums and their derivatives, among which guar gum and its modified products are the most widely used. Such materials can achieve extremely high thickening efficiency at a lower concentration due to the formation of a strong hydrogen bond network on the molecular chain, and have significant cost-effectiveness. In particular, another type of biological polymer, xanthan gum, has unique rheological properties. Xanthan molecules exhibit a unique rigid double helix structure in aqueous solution, and the helices form a reversible three-dimensional network through weak non-covalent bonding. This structural property endows xanthan gum with excellent "pseudoplasticity": under static or low shear conditions, the network structure is complete, and the solution exhibits high viscosity, thereby providing excellent static suspension capacity for proppants; when subjected to high shear, the network structure is rapidly destroyed, and the molecular chains are oriented along the flow direction, resulting in a sharp drop in viscosity and significantly reducing the construction friction. This rheological behavior of "thickening when static and thinning when dynamic" is highly consistent with the "pumping-into fracture-static sand carrying" process of the fracturing process, making xanthan gum theoretically one of the ideal thickening agents for fracturing fluid.

[0004] However, the inherent biological nature of natural bio-gums, including excellent xanthan gum, leads to an insurmountable congenital defect, i.e. poor temperature resistance and salt tolerance. In high salinity formation water, especially in the environment rich in high valence metal ions such as calcium and magnesium, salt ions can strongly destroy the hydrogen bond and electrostatic interaction stabilizing the double helix structure of xanthan gum, leading to the collapse of its three-dimensional network structure and a significant decrease in thickening capacity. More seriously, under the synergistic effect of high temperature and high valence metal ions, the molecular chain of xanthan gum is prone to degradation and chain scission, resulting in permanent loss of viscosity, thus causing a series of construction risks such as premature gel breaking of fracturing fluid and settlement and accumulation of proppant, greatly limiting its application in harsh reservoir conditions.

[0005] In order to overcome the limitations of bio-gums, synthetic polymer thickeners, especially polyacrylamide and its multi-component copolymers, have emerged. This kind of material can realize precise control of molecular weight and functional groups through molecular design, and its chemical stability is generally better than that of natural products, so it shows relatively better potential in temperature resistance and salt tolerance. However, the linear molecular structure of traditional polyacrylamide is difficult to simulate the significant pseudoplasticity of xanthan gum, and its shear thinning behavior is often accompanied by irreversible mechanical degradation to some extent. In order to achieve sufficient viscosity in high temperature and high salt formation, the amount of polymer often needs to be increased, but this will lead to high initial viscosity of fracturing fluid, increased pumping resistance, increased construction energy consumption, and even in some cases, increased risk of formation damage.

[0006] In summary, the thickeners in the prior art face a dilemma: natural bio-gums (represented by xanthan gum) have an ideal pseudoplastic rheological pattern but poor temperature resistance and salt tolerance; while synthetic polymers (represented by polyacrylamide) have improved temperature resistance and salt tolerance, but it is difficult to balance excellent pseudoplasticity and unsatisfactory thickening effect in high salt environment. SUMMARY

[0007] In order to solve the technical problems mentioned in the background art, the purpose of the present application is to provide a preparation method of a high salt-tolerant polymer fracturing fluid thickener.

[0008] The purpose of the present application can be achieved by the following technical solutions: The high salt-tolerant polymer fracturing fluid thickener is composed of a polymer thickener and auxiliary additives, and through optimization of the ratio and synergistic effect, the controllable rheological behavior of the fracturing fluid in different construction stages is realized. The specific technical content disclosure includes two aspects, one is the synthesis of the polymer thickener, and the other is the preparation of the thickener. The specific content is as follows: I. Synthesis of polymer thickener Step 1: N-(2-aminoethyl) acrylamide, ω-chloro n-alkyl alcohol and toluene are mixed, nitrogen is introduced, the temperature is raised to 90-100℃, potassium carbonate is slowly added, and the reaction is stirred for 5-7h. After cooling, it is dried with anhydrous magnesium sulfate, filtered, and then the toluene is removed by rotary evaporation under reduced pressure to obtain an intermediate; In the above reaction, the addition ratio of N-(2-aminoethyl) acrylamide, ω-chloro n-alkyl alcohol, potassium carbonate and toluene is 0.1 mol: 0.2 mol: 15-20 g: 300-400 mL, and ω-chloro n-alkyl alcohol is substituted with N-(2-aminoethyl) acrylamide. Preferably, the ω-chloro n-alkyl alcohol is one of 8-chloro-1-octanol and 10-chloro-1-decanol. The length of the alkyl alcohol chain is modified to easily form an association entanglement force with moderate force in an aqueous environment.

[0009] Step 2: The intermediate is pre-mixed with ethanol, 1-bromopropane is added and mixed, the temperature is raised to 70-75℃ to reflux for 12-16h, and then the ethanol is removed by rotary evaporation to obtain a modified monomer; In the above reaction, the addition ratio of the intermediate, 1-bromopropane and ethanol is 0.1 mol: 0.13-0.15 mol: 200-280 mL, and the highly active 1-bromopropane is quaternized with the intermediate.

[0010] Step 3: AM, AMPS, NVP, modified monomer and water are pre-mixed, isopropyl alcohol and ammonium persulfate solution are added, the temperature is raised to 40-50℃ and stirred for 3.5-4.2h, then sodium bisulfite solution is added and left to stand for 12h, the supernatant is removed and dried to constant weight to obtain a polymer thickening agent; In the above reaction, the addition ratio of AM, AMPS, NVP, modified monomer, ammonium persulfate, sodium bisulfite, isopropyl alcohol and water is 60-80 mmol: 20-30 mmol: 10-15 mmol: 25-35 mmol: 0.12-0.17 g: 0.2-0.3 g: 8-12 mL: 160-200 mL, and the monomers are added to form a polymer under the initiation of ammonium persulfate.

[0011] II. Preparation of the gelling agent The specific components of the gelling agent are: 3.5-4.2wt% surfactant, 0.7-0.9wt% stabilizer and 1.3-1.8wt% crosslinking agent, and the balance is a polymer thickening agent.

[0012] The specific configuration method is: mix the raw materials of each component uniformly, add water to the mixture to form a gel, and spray dry to form a fine and uniform gelling agent.

[0013] Preferably, the surfactant is sodium dodecyl sulfonate, which facilitates the dissolution and dispersion of the thickener in the fracturing fluid and allows for rapid preparation.

[0014] Preferably, the stabilizer is one of sodium oxalate and potassium oxalate, which improves the stability of the polymer at high temperatures.

[0015] Preferably, the crosslinking agent is an organoboron crosslinking agent, which forms a stable gel during the initial solution preparation process, improving the initial suspension of the proppant.

[0016] The beneficial effects of this invention are: The high salt-resistant polymer fracturing fluid thickener prepared in this invention successfully integrates the pseudoplasticity of xanthan gum with the temperature and salt resistance of synthetic polymers through ingenious molecular structure design, creating a novel thickening material with superior performance. Its beneficial effects are mainly reflected in its unique molecular structure and the resulting breakthrough in comprehensive performance. The core of this polymer lies in the synergistic system of alternating zwitterionic structures and flexible long alkyl alcohol chains. On the molecular chain, quaternary ammonium cation centers and sulfonic acid anionic groups (AMPS) are arranged alternately, forming strong inter-chain electrostatic adsorption. This intrinsic electrostatic interaction, unaffected by significant interference from external salt ions, constitutes the primary foundation for the polymer to maintain molecular chain extension and structural rigidity even in high-temperature and high-salt environments. Simultaneously, the longer alkyl alcohol chains introduced through molecular design intertwine and entangle with each other in an aqueous environment due to their hydrophobic effect, forming dynamic and reversible physical cross-linking points.

[0017] The synergistic effect of these two mechanisms endows the polymer with unique pseudoplasticity. Under static or low-shear conditions, strong electrostatic adsorption and hydrophobic entanglement jointly construct a stable and transient three-dimensional network structure, exhibiting extremely high viscosity, thus ensuring perfect suspension and low filtration of the proppant. Once subjected to high shear, such as during pumping, these weaker physical cross-linking points can be reversibly disrupted. The mobility of the flexible alkyl chains allows the molecular chains to easily align along the flow direction, resulting in a significant decrease in viscosity, greatly reducing construction friction and energy consumption. Once the shear force is removed, the electrostatic attraction and hydrophobic association between the molecular chains can be instantly restored, the network structure is rebuilt, and the viscosity rapidly recovers, thereby regaining excellent proppant carrying capacity in the fracture. This rapid and reversible response characteristic allows the thickener to intelligently adapt to the needs of different stages of fracturing operations. In summary, this invention not only fundamentally solves the inherent defects of poor salt resistance of traditional bio-adhesives and insufficient pseudoplasticity of conventional polyacrylamide, but also achieves a leapfrog improvement in the performance of fracturing fluid thickeners under harsh conditions of high temperature and high salt, providing strong technical support for the efficient development of unconventional oil and gas resources. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1: Synthesis of a polymer thickener and formulation of a compound thickener, the specific implementation method is as follows: I. Synthesis of Polymer Thickeners Step 1: Mix N-(2-aminoethyl)acrylamide, 8-chloro-1-octanol and toluene, purge with nitrogen for protection, heat to 90°C, slowly add potassium carbonate and stir for 5.5 h. The ratio of N-(2-aminoethyl)acrylamide, 8-chloro-1-octanol, potassium carbonate and toluene is 0.1 mol: 0.2 mol: 15 g: 300 mL. After cooling, dry with anhydrous magnesium sulfate, filter, and then remove toluene by rotary evaporation under reduced pressure to obtain the intermediate.

[0020] Step 2: Take the intermediate and ethanol and stir to premix. Add 1-bromopropane and stir to mix well. Heat to 70℃ and reflux for 13h. The ratio of intermediate, 1-bromopropane and ethanol is 0.1mol:0.13mol:200mL. Then remove the ethanol by rotary evaporation to obtain the modified monomer.

[0021] Step 3: AM (acrylamide), AMPS (2-acrylamido-2-methylpropanesulfonic acid), NVP (N-vinylpyrrolidone), modified monomer, and water were stirred and premixed. Isopropanol and ammonium persulfate solution were then added, and the mixture was heated to 40°C and stirred for 3.8 h. After that, sodium bisulfite solution was added and allowed to stand for 12 h. The addition ratio of AM, AMPS, NVP, modified monomer, ammonium persulfate, sodium bisulfite, isopropanol, and water was 60 mmol: 30 mmol: 10 mmol: 35 mmol: 0.12 g: 0.2 g: 8 mL: 160 mL. After removing the supernatant, the mixture was dried to constant weight to obtain the polymer thickener.

[0022] II. Preparation of Thickener The components are calculated by weight percentage as follows: surfactant 3.5 wt%, sodium dodecyl sulfonate; stabilizer 0.8 wt%, sodium oxalate; crosslinking agent 1.3 wt%, organoboron crosslinking agent YC-JL-01; balance is the polymer thickener prepared in this embodiment.

[0023] Mix all components thoroughly, then add 3.5 times the weight of water to form a thin gel, spray dry to shape, and form a fine and uniform thickener.

[0024] Example 2: Synthesis of a polymer thickener and formulation of a compound thickener, the specific implementation method is as follows: I. Synthesis of Polymer Thickeners Step 1: Mix N-(2-aminoethyl)acrylamide, 8-chloro-1-octanol and toluene, purge with nitrogen for protection, heat to 90°C, slowly add potassium carbonate and stir for 5 hours. The ratio of N-(2-aminoethyl)acrylamide, 8-chloro-1-octanol, potassium carbonate and toluene is 0.1 mol: 0.2 mol: 17 g: 300 mL. After cooling, dry with anhydrous magnesium sulfate, filter, and then remove toluene by rotary evaporation under reduced pressure to obtain the intermediate.

[0025] Step 2: Take the intermediate and ethanol and stir to premix. Add 1-bromopropane and stir to mix well. Heat to 70℃ and reflux for 12h. The ratio of intermediate, 1-bromopropane and ethanol is 0.1mol:0.14mol:220mL. Then remove the ethanol by rotary evaporation to obtain the modified monomer.

[0026] Step 3: AM, AMPS, NVP, modified monomer and water are stirred and premixed, then isopropanol and ammonium persulfate solution are added, the temperature is raised to 45℃ and stirred for 3.5h, then sodium bisulfite solution is added and allowed to stand for 12h. The addition ratio of AM, AMPS, NVP, modified monomer, ammonium persulfate, sodium bisulfite, isopropanol and water is 70mmol:25mmol:12mmol:30mmol:0.15g:0.3g:10mL:180mL. After removing the supernatant, the mixture is dried to constant weight to obtain the polymer thickener.

[0027] II. Preparation of Thickener The components are calculated by weight percentage as follows: surfactant 3.8 wt%, sodium dodecyl sulfonate; stabilizer 0.7 wt%, sodium oxalate; crosslinking agent 1.4 wt%, organoboron crosslinking agent YC-JL-01; balance is the polymer thickener prepared in this embodiment.

[0028] Mix all components thoroughly, then add 3.5 times the weight of water to form a thin gel, spray dry to shape, and form a fine and uniform thickener.

[0029] Example 3: Synthesis of a polymer thickener and formulation of a compound thickener, the specific implementation method is as follows: I. Synthesis of Polymer Thickeners Step 1: Mix N-(2-aminoethyl)acrylamide, 10-chloro-1-decyl alcohol and toluene, purge with nitrogen for protection, heat to 100℃, slowly add potassium carbonate and stir for 6.5 h. The ratio of N-(2-aminoethyl)acrylamide, 10-chloro-1-decyl alcohol, potassium carbonate and toluene is 0.1 mol: 0.2 mol: 20 g: 400 mL. After cooling, dry with anhydrous magnesium sulfate, filter, and then remove toluene by rotary evaporation under reduced pressure to obtain the intermediate.

[0030] Step 2: Take the intermediate and ethanol and stir to premix. Add 1-bromopropane and stir to mix well. Heat to 75℃ and reflux for 15h. The ratio of intermediate, 1-bromopropane and ethanol is 0.1mol:0.15mol:280mL. Then remove the ethanol by rotary evaporation to obtain the modified monomer.

[0031] Step 3: AM, AMPS, NVP, modified monomer and water are stirred and premixed, then isopropanol and ammonium persulfate solution are added, the temperature is raised to 50℃ and stirred for 4 hours, then sodium bisulfite solution is added and allowed to stand for 12 hours. The addition ratio of AM, AMPS, NVP, modified monomer, ammonium persulfate, sodium bisulfite, isopropanol and water is 80mmol:20mmol:15mmol:25mmol:0.17g:0.3g:12mL:200mL. After removing the supernatant, the mixture is dried to constant weight to obtain the polymer thickener.

[0032] II. Preparation of Thickener The components are calculated by weight percentage as follows: surfactant 4.2 wt%, sodium dodecyl sulfonate; stabilizer 0.9 wt%, potassium oxalate; crosslinking agent 1.8 wt%, organoboron crosslinking agent YC-JL-01; balance is the polymer thickener prepared in this embodiment.

[0033] Mix all components thoroughly, then add 4 times the weight of water to form a thin gel, spray dry to shape, and form a fine and uniform thickener.

[0034] Example 4: Synthesis of a polymer thickener and formulation of a compound thickener, the specific implementation method is as follows: I. Synthesis of Polymer Thickeners Step 1: Mix N-(2-aminoethyl)acrylamide, 10-chloro-1-decyl alcohol and toluene, purge with nitrogen for protection, heat to 100℃, slowly add potassium carbonate and stir for 7 hours. The ratio of N-(2-aminoethyl)acrylamide, 10-chloro-1-decyl alcohol, potassium carbonate and toluene is 0.1mol:0.2mol:19g:380mL. After cooling, dry with anhydrous magnesium sulfate, filter, and then remove toluene by rotary evaporation under reduced pressure to obtain the intermediate.

[0035] Step 2: Take the intermediate and ethanol and stir to premix. Add 1-bromopropane and stir to mix well. Heat to 75℃ and reflux for 16h. The ratio of intermediate, 1-bromopropane and ethanol is 0.1mol:0.14mol:260mL. Then remove the ethanol by rotary evaporation to obtain the modified monomer.

[0036] Step 3: AM, AMPS, NVP, modified monomer and water are stirred and premixed, then isopropanol and ammonium persulfate solution are added, the temperature is raised to 50℃ and stirred for 4.2 h, then sodium bisulfite solution is added and allowed to stand for 12 h. The addition ratio of AM, AMPS, NVP, modified monomer, ammonium persulfate, sodium bisulfite, isopropanol and water is 75 mmol: 28 mmol: 14 mmol: 28 mmol: 0.15 g: 0.25 g: 11 mL: 190 mL. After removing the supernatant, the mixture is dried to constant weight to obtain the polymer thickener.

[0037] II. Preparation of Thickener The components are calculated by weight percentage as follows: surfactant 4 wt%, sodium dodecyl sulfonate; stabilizer 0.78 wt%, potassium oxalate; crosslinking agent 1.7 wt%, organoboron crosslinking agent YC-JL-01; balance is the polymer thickener prepared in this embodiment.

[0038] Mix all components thoroughly, then add 4 times the weight of water to form a thin gel, spray dry to shape, and form a fine and uniform thickener.

[0039] In the comparative example, a commercially available water-soluble acrylamide copolymer for fracturing fluids was used as the thickening material, specifically FTK230. Referring to Example 4, FTK230 was used to replace the polymer thickener in equal amounts, and the rest of the implementation process was exactly the same.

[0040] The thickener was prepared into a fracturing fluid base at 0.8% wt%. Different salt concentrations were prepared using sodium chloride and calcium chloride, respectively. The results were tested using an RH-30 rheometer at 30℃ for 170 seconds. -1 Apparent viscosity was determined at shear rates, and the specific test data are shown in Tables 1 and 2. Table 1 Viscosity test results under NaCl salt environment

[0041] Table 2 Viscosity test results under CaCl2 salt environment

[0042] As can be seen from the test data in Tables 1 and 2, the fracturing fluid prepared with the thickener prepared in the example exhibits extremely high stability with changes in salt concentration, demonstrating excellent salt resistance.

[0043] The fracturing fluid base fluid prepared above was adjusted to a salt concentration of 20000 mg / L with calcium chloride to simulate a real high-salt environment. The apparent viscosity at different shear rates was measured at 80°C to characterize the thickening effect of the thickener during actual well injection. The results are shown in Table 3 below, which presents the viscosity test results of Example 4 and the comparative example at different shear rates. Table 3. Viscosity test results of Example 4 and the comparative example at different shear rates.

[0044] Based on the test data in Table 3, it can be seen that the viscosity of the fracturing fluid prepared by the thickener in Example 4 is quite sensitive to the shear rate. The viscosity is high at low shear rates, and decreases sharply as the shear rate increases, exhibiting pseudoplastic characteristics. This is beneficial for fracturing fluid injection and fracturing. Under low shear conditions, maintaining good viscosity is conducive to the suspension and stability of the support material. During high-speed injection, a high shear rate and low viscosity of the fracturing fluid are conducive to smooth injection. However, under low-speed, slow-flow conditions downhole, the low shear rate and the recovery of high viscosity are conducive to reducing the loss of fracturing fluid and also to diversion fracturing, thereby improving fracturing efficiency.

[0045] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0046] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing a high-salt-resistance polymer fracturing fluid thickener, comprising granulation of a polymer thickener and auxiliary additives, characterized in that, The preparation method of the polymer thickener is as follows: Step 1: Mix N-(2-aminoethyl)acrylamide, ω-chloro-n-alkyl alcohol and toluene, and under nitrogen protection, slowly add potassium carbonate at 90-100℃ and stir for 5-7 hours to prepare an intermediate; Step 2: Premix the intermediate with ethanol, add 1-bromopropane and mix well, heat to 70-75℃ and reflux for 12-16h to prepare the modified monomer; Step 3: Premix AM, AMPS, NVP, modified monomers and water, then add isopropanol and ammonium persulfate solution, heat to 40-50℃ and stir for 3.5-4.2h, then add sodium bisulfite solution and let stand for 12h to prepare polymer thickener.

2. The method for preparing a high salt water resistant polymer fracturing fluid thickener according to claim 1, characterized in that, The addition ratio of N-(2-aminoethyl)acrylamide, ω-chloro-n-alkyl alcohol, potassium carbonate and toluene is 0.1mol:0.2mol:15-20g:300-400mL.

3. The method for preparing a high salt water resistant polymer fracturing fluid thickener according to claim 2, characterized in that, ω-Chloroalkyl alcohol is one of 8-chloro-1-octanol and 10-chloro-1-decanol.

4. The method for preparing a high salt water resistant polymer fracturing fluid thickener according to claim 2, characterized in that, The ratio of intermediate, 1-bromopropane and ethanol is 0.1 mol: 0.13-0.15 mol: 200-280 mL.

5. The method for preparing a high salt water resistant polymer fracturing fluid thickener according to claim 4, characterized in that, The dosage ratio of AM, AMPS, NVP, modified monomer, ammonium persulfate, sodium bisulfite, isopropanol and water is 60-80 mmol: 20-30 mmol: 10-15 mmol: 25-35 mmol: 0.12-0.17 g: 0.2-0.3 g: 8-12 mL: 160-200 mL.

6. The method for preparing a high salt water resistant polymer fracturing fluid thickener according to claim 5, characterized in that, The auxiliary additives consist of: 3.5-4.2 wt% surfactant, 0.7-0.9 wt% stabilizer, and 1.3-1.8 wt% crosslinking agent, with the remainder being polymer thickener.

7. The method for preparing a high salt water resistant polymer fracturing fluid thickener according to claim 6, characterized in that, The surfactant is sodium dodecyl sulfonate.

8. The method for preparing a high salt water resistant polymer fracturing fluid thickener according to claim 6, characterized in that, The stabilizer is either sodium oxalate or potassium oxalate.

9. The method for preparing a high salt water resistant polymer fracturing fluid thickener according to claim 6, characterized in that, The crosslinking agent is an organoboron crosslinking agent.

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