A high-temperature-resistant hyperbranched polymer tackifier for composite calcium salt water completion fluid and a preparation method and application thereof

Abstract

The application provides a high-temperature-resistant hyperbranched polymer tackifier for composite calcium salt water completion fluid and a preparation method and application thereof. The preparation method of the tackifier comprises the following steps: mixing gamma-aminopropyl triethoxysilane, diethylene glycol and triethylene glycol, stirring uniformly and then reacting; after the reaction is completed, high-reactivity branched monomers are obtained through dialysis and freeze-drying; the salt-resistant monomers and the high-reactivity branched monomers are added into deionized water, and then acrylamide monomers, rigid cyclic monomers and hydrophobic monomers are added to obtain a monomer solution; after the pH value of the monomer solution is adjusted, nitrogen is blown to remove oxygen, then the temperature is increased to a reaction temperature, an initiator is added, and a polymerization reaction is initiated by heat; after the reaction is completed, ethanol is added to the obtained reaction solution for precipitation, and then filtration, vacuum drying and crushing are performed to obtain the tackifier. The tackifier has excellent temperature resistance and salt resistance, and still has excellent tackifying performance after aging in a 200 DEG C high-temperature composite calcium salt environment.

Description

TECHNICAL FIELD

[0001] The application relates to an anti-high-temperature hyperbranched polymer tackifier for a composite calcium salt water completion fluid and a preparation method and application thereof, and belongs to the field of oil field chemistry in the petroleum industry. BACKGROUND

[0002] In the process of drilling deep and ultra-deep oil and gas layers, with the increase of well depth, the number of complex formations such as high temperature and high pressure increases, and the development difficulty increases, which puts forward new requirements for the performance of completion fluids. Under the action of high pressure difference, solid particles in the completion fluid easily invade the reservoir pore cracks, block the oil and gas seepage channel, and cause reservoir damage and reduce the production capacity. The solid-free completion fluid has excellent lubricity and reservoir protection, and is the mainstream direction of the development of deep and ultra-deep well completion fluids.

[0003] The tackifier can increase the viscosity and shear force of the completion fluid to suspend and carry the rock, and is the core additive of the solid-free completion fluid. However, in the deep and ultra-deep high-temperature environment, the existing tackifier molecules are prone to degradation and conformational transition such as viscosity, which leads to the performance failure of the tackifier, causes the viscosity of the solid-free completion fluid to decrease and the filtration loss to increase, and the like. The deep and ultra-deep formation has high pressure, and the solid-free completion fluid balances the formation pressure by using soluble salt (formate salt, inorganic salt) to increase the density of the completion fluid. Under high-temperature environment, the formate salt can enhance the temperature resistance of the polymer, but its cost is too high, which is difficult to meet the large-scale popularization and application. Most of the existing linear polymer tackifiers are extremely prone to curling and agglomeration in the high-concentration inorganic high-valence salt (CaCl2, CaBr2, etc.) water environment, which leads to the precipitation of the polymer and causes the performance failure of the completion fluid.

[0004] Chinese patent document CN104650827A develops a temperature-resistant micro-crosslinking tackifier by reacting alkenyl sulfonic acid, alkenyl amide and alkenyl benzene, which still has good tackifying effect after 16h of hot rolling aging at 165℃, and is better than the foreign similar product HE300, but its temperature resistance still needs to be further improved (>200℃) to meet the completion needs of deep and ultra-deep wells. Chinese patent document CN118459660A uses 2-acrylamido-2-methylpropanesulfonic acid, dimethylaminopropyl acrylamide, sodium p-styrenesulfonate, hydrophobic monomer and micro-crosslinking agent as raw materials, initiates polymerization into a linear copolymer through an initiator, and is blended with micron-sized inert bridging materials to develop a calcium chloride brine completion fluid resistant to high temperature, which can resist 170℃, and the temperature resistance still needs to be further improved. Chinese patent document CN114214049A discloses a preparation method of a solid-free tackifying workover fluid for ultra-deep and ultra-high-temperature oil and gas wells, which adds an ultra-high-temperature polymer crosslinking agent, an ultra-high-temperature polymer stabilizer and an ultra-high-temperature thermal stabilizer into a thickening agent solution, so that the service temperature of the thickening agent reaches 180℃, which meets the requirement that the performance of the tackifier in the high-temperature solid-free brine remains stable, but the brine density used by the tackifier is only

[0005] 1.1~1.3g / cm 3 , and is monovalent sodium salt, and does not meet the use condition of high density completion fluid.

[0006] Therefore, how to enhance the stability of the tackifier for the solid-free completion fluid in the environment of high temperature and high salt (CaCl2, CaBr2), and maintain the performance of tackifying, has important significance for the basic research of the solid-free completion fluid of deep and ultra-deep layer. SUMMARY

[0007] In view of the deficiencies of the prior art, especially the problems that the linear polymer tackifier is easy to degrade in high temperature environment, and is easy to curl and agglomerate in high salt water environment, the application provides an anti-high-temperature hyperbranched polymer tackifier for composite calcium salt water completion fluid, and a preparation method and application thereof.The tackifier can resist high temperature (≥200 DEG C), resist composite calcium salt (CaCl2 and CaBr2), and realize the effect of tackifying.

[0008] The technical scheme of the application is as follows:

[0009] A preparation method of an anti-high-temperature hyperbranched polymer tackifier for composite calcium salt water completion fluid, comprising the following steps:

[0010] (1) Preparation of high-reactivity branched monomer

[0011] Mix γ-aminopropyl triethoxysilane (KH550), diethylene glycol and triethylene glycol, stir uniformly, and then react; after the reaction is completed, dialysis, freeze-drying are performed to obtain the high-reactivity branched monomer;

[0012] (2) Preparation of anti-high-temperature hyperbranched polymer tackifier

[0013] The salt-resistant monomer and the high-reactivity branched monomer prepared in step (1) are added to deionized water, and then the acrylamide monomer, the rigid cyclic monomer and the hydrophobic monomer are added to obtain a monomer solution; after adjusting the pH value of the monomer solution, nitrogen is blown to remove oxygen, then the temperature is raised to the reaction temperature, the initiator is added, and the polymerization reaction is initiated by heating; after the reaction is completed, ethanol is added to the obtained reaction solution for precipitation, and then filtration, vacuum drying and crushing are performed to obtain the anti-high-temperature hyperbranched polymer tackifier for composite calcium salt water completion fluid.

[0014] According to the application, the mass ratio of the γ-aminopropyl triethoxysilane (KH550), diethylene glycol and triethylene glycol in step (1) is 1:3-5:1-3, and is further preferably 1:4:2.

[0015] According to the application, the temperature of the reaction in step (1) is 150-200 DEG C, and the reaction time is 2-4h.

[0016] According to the application, preferably, the dialysis step in step (1) is that the product obtained after the reaction is completed is loaded into a dialysis bag, and dialysis is performed in deionized water for 24-48 h; the molecular weight cut-off of the dialysis bag is 3500 Da; the temperature of the freeze-drying is 0-5 ℃, and the freeze-drying time is 10-15 h.

[0017] According to the application, preferably, the anti-salt monomer in step (2) is 2-acrylamido-2-methylpropanesulfonic acid (AMPS), sodium p-styrenesulfonate (SSS) or sodium vinyl sulfonate (VS).

[0018] According to the application, preferably, the acrylamide monomer in step (2) is acrylamide (AM), N,N-dimethyl acrylamide (DMAA) or N-isopropyl acrylamide (NIPAM).

[0019] According to the application, preferably, the rigid cyclic monomer in step (2) is N-vinyl pyrrolidone (NVP).

[0020] According to the application, preferably, the hydrophobic monomer in step (2) is dimethyl ditetradecyl ammonium bromide (DTAB), allyl polyethylene glycol or hexadecyl dimethyl allyl ammonium chloride (DMAAC16); the allyl polyethylene glycol is APEG-800, APEG-1000, APEG-1200, APEG-1300, APEG-2000 or APEG-2200.

[0021] According to the application, preferably, the mass ratio of the anti-salt monomer, the high-reactivity branched monomer, the acrylamide monomer, the rigid cyclic monomer and the hydrophobic monomer in step (2) is 5-7:0.2:4:1:0.3, and more preferably 6:0.2:4:1:0.3.

[0022] According to the application, preferably, the mass ratio of the anti-salt monomer to deionized water in step (2) is 1:4-10.

[0023] According to the application, preferably, the pH value of the monomer solution is adjusted to 5-8, and more preferably 6-7 in step (2); the pH value of the monomer solution is adjusted by using a sodium hydroxide aqueous solution with a mass fraction of 20-40%.

[0024] According to the application, preferably, the initiator in step (2) is potassium persulfate (KPS), ammonium persulfate (APS), azobisisobutyronitrile (AIBN) or azobisdimethylvaleronitrile hydrochloride (V50); the mass of the initiator is 0.01-0.2% of the total mass of the anti-salt monomer, the high-reactivity branched monomer, the acrylamide monomer, the rigid cyclic monomer and the hydrophobic monomer, and more preferably 0.05-0.1%.

[0025] According to the application, preferably, the reaction temperature in step (2) is 55-65 DEG C, and the polymerization time is 3-5 h.

[0026] According to the application, preferably, the volume ratio of the ethanol to the mass of the salt-resistant monomer in step (2) is 15-50 mL:1 g.

[0027] According to the application, preferably, the temperature of the vacuum drying in step (2) is 70-80 DEG C, and the vacuum drying time is 8-10 h.

[0028] The application further provides a high-temperature-resistant hyperbranched polymer tackifier for composite calcium salt water completion fluid, which is prepared by the above preparation method.

[0029] According to the application, the high-temperature-resistant hyperbranched polymer tackifier for composite calcium salt water completion fluid is applied in the composite calcium salt water completion fluid; preferably, the concentration of the high-temperature-resistant hyperbranched polymer tackifier for composite calcium salt water completion fluid in the composite calcium salt water completion fluid is 10-15 g / L; the composite calcium salt includes calcium chloride and calcium bromide, and the density of the composite calcium salt water completion fluid is preferably 1.70 g / cm 3 .

[0030] The technical features and advantages of the application are as follows:

[0031] 1. The application first selects a specific silane coupling agent to react with a specific proportion and specific type of polyol to obtain a branched monomer with high reactivity, then introduces it into the tackifier, introduces the active point to make it have a group that can further react, and reacts with other functional monomers to generate a high-temperature-resistant and high-salt-resistant product. The proportion of the branched monomer with high reactivity is too high or too low, which will reduce the performance of the tackifier.

[0032] 2. The tackifier of the application introduces acrylamide monomers, which can not only improve the high-temperature hydrolysis resistance of the polymer but also increase the molecular weight of the polymer, further enhancing the temperature resistance of the polymer. The introduction of salt-resistant monomers can improve the salt resistance of the polymer. The introduction of rigid cyclic monomers can further improve the stability of the polymer under high temperature conditions. The introduction of hydrophobic monomers can form a spatial network structure between the hydrophobic groups in the polymer aqueous solution due to the hydrophobic interaction, increase the hydrodynamic volume, and show good tackifying property. In a salt solution, the hydrophobic interaction is enhanced due to the increase of the solution polarity, so that the polymer shows obvious salt thickening effect and good salt resistance.

[0033] 3、The anti-temperature and anti-salt ability of the synthetic polymer tackifier is excellent, and the tackifier still has excellent tackifying performance after aging in a 200℃ high temperature and a complex calcium salt environment, and has a wide application prospect in a solid-free completion fluid. DETAILED DESCRIPTION

[0034] The application will be further described below in conjunction with specific examples, but is not limited thereto.

[0035] Meanwhile, the experimental methods in the following examples are all conventional methods unless otherwise specified; and the reagents, materials and equipment are all commercially available unless otherwise specified.

[0036] Example 1

[0037] A preparation method of a high-temperature-resistant hyperbranched polymer tackifier for a complex calcium salt water completion fluid, comprising the following steps:

[0038] (1) Preparation of a high-reactivity branched monomer

[0039] 1g of γ-aminopropyl triethoxysilane (KH550), 4g of diethylene glycol (CAS No. 111-46-6) and 2g of triethylene glycol (CAS No. 112-27-6) were mixed, stirred uniformly, and then reacted at 180℃ for 3h; after the reaction was completed, the obtained product was loaded into a dialysis bag with a molecular weight cut-off of 3500Da, dialyzed in deionized water for 48h, and then freeze-dried at 4℃ for 10h to obtain a high-reactivity branched monomer.

[0040] (2) Preparation of a high-temperature-resistant high-salt hyperbranched tackifier

[0041] 18g of sodium p-styrenesulfonate (SSS) and 0.6g of the high-reactivity branched monomer obtained in step (1) were weighed and added to 100g of deionized water, then 12g of N,N-dimethylacrylamide (DMAA), 3g of N-vinylpyrrolidone (NVP) and 0.9g of dimethyl ditetradecyl ammonium bromide (DTAB) were added to the system, stirred uniformly to obtain a monomer solution; the pH of the monomer solution was adjusted to 6 using a 20% mass fraction sodium hydroxide aqueous solution; then nitrogen was blown for 30min to remove oxygen, the temperature was raised to 60℃, 0.03g of azobisdimethylaminoformamide hydrochloride (V50) was added, and the reaction was carried out at 60℃ for 4h; after the reaction was completed, 500mL of anhydrous ethanol was added to the obtained reaction solution for precipitation, then filtration was performed, the obtained solid was vacuum dried at 70℃ for 10h, and the dried product was crushed to obtain a high-temperature-resistant hyperbranched polymer tackifier for a complex calcium salt water completion fluid.

[0042] Example 2

[0043] A preparation method of the polymer viscosifier for composite calcium salt water completion fluid is as described in Embodiment 1, except that the reaction temperature in step (2) is 55℃.

[0044] Comparative Example 1

[0045] A preparation method of the polymer viscosifier for composite calcium salt water completion fluid comprises the following steps:

[0046] 18g of sodium p-styrenesulfonate (SSS) is weighed into 100g of deionized water, then 12g of N,N-dimethylacrylamide (DMAA), 3g of N-vinylpyrrolidone (NVP), and 0.9g of dimethyl diterdecyl ammonium bromide (DTAB) are added to the system, and stirred uniformly to obtain a monomer solution; the pH of the monomer solution is adjusted to 6 using a 20% mass fraction sodium hydroxide aqueous solution; then the system is deoxygenated for 30min under nitrogen, heated to 50℃, and 0.03g of azobisdimethylaminoformamide hydrochloride (V50) is added, and reacted at 60℃ for 4h; after the reaction is completed, 500mL of anhydrous ethanol is added for precipitation, then filtered, and the obtained solid is vacuum dried at 70℃ for 10h; the dried product is crushed to obtain the polymer viscosifier for composite calcium salt water completion fluid.

[0047] No high-reactivity branched monomer is added in the viscosifier of the present comparative example.

[0048] Comparative Example 2

[0049] A preparation method of the polymer viscosifier for composite calcium salt water completion fluid is as described in Embodiment 4, except that no salt-resistant monomer sodium p-styrenesulfonate (SSS) is added in step (2).

[0050] Comparative Example 3

[0051] A preparation method of the polymer viscosifier for composite calcium salt water completion fluid is as described in Embodiment 4, except that no acrylamide monomer N,N-dimethylacrylamide (DMAA) is added in step (2).

[0052] Comparative Example 4

[0053] A preparation method of the polymer viscosifier for composite calcium salt water completion fluid is as described in Embodiment 4, except that no rigid cyclic monomer N-vinylpyrrolidone (NVP) is added in step (2).

[0054] Comparative Example 5

[0055] A preparation method of the polymer viscosifier for composite calcium salt water completion fluid is as described in Embodiment 4, except that no hydrophobic monomer dimethyl diterdecyl ammonium bromide (DTAB) is added in step (2).

[0056] Comparative Example 6

[0057] A method for preparing a polymer viscosifier for a composite calcium salt water completion fluid is described in Example 4, except that in step (2), equal mass of KH550 is used instead of the high reactivity branched monomer.

[0058] Comparative Example 7

[0059] A method for preparing a polymer viscosifier for a composite calcium salt water completion fluid is described in Example 4, except that in step (2), equal mass of N,N-methylenebisacrylamide (MBA) is used instead of the high reactivity branched monomer.

[0060] Comparative Example 8

[0061] The viscosifier HE300 is commercially purchased.

[0062] Test Example

[0063] The polymer viscosifiers prepared in the examples and comparative examples are subjected to the following tests.

[0064] 1. Determination of the viscosity average molecular weight of the viscosifier

[0065] Referring to the national standard GBT 12005.10-1992 "Determination of the molecular weight of polyacrylamide by viscosity method", the flow time of the solvent (1.0 mol / L NaCl solution) and the solution is respectively determined at 30℃ by using a full-automatic capillary viscometer, the Huggins formula and the Kraemer formula are jointly used to calculate the intrinsic viscosity [η] of the viscosifier, and the viscosity average molecular weight Mη of the viscosifier is calculated by using the empirical formula Mη=(10000[η] / 3.73)1.515.

[0066] 2. Effect of the viscosifier on the rheological properties and filtration loss performance of the base fluid before and after aging

[0067] Preparation of the base fluid:

[0068] Preparation of the solid-free completion fluid sample: 400 mL of deionized water is taken, 2 g (0.5%) of the viscosifier sample of the examples and comparative examples is added respectively, and stirred at a speed of 6000 r / min at room temperature for 20 min; then, 236 g of calcium chloride and 500 g of calcium bromide are added, and stirred at a speed of 4000 r / min at room temperature for 20 min, to obtain a solid-free completion fluid, with a density of 1.70 g / cm 3 ;

[0069] Aging treatment of the completion fluid sample: the above completion fluid sample is placed in a roller heating furnace, the aging temperature is set to 180℃ or 200℃, and the aging time is 16 h.

[0070] The rheological and filtration properties of the above-prepared solution were evaluated in accordance with GB16783.1-2014 "Field Testing of Drilling Fluids for Petroleum and Natural Gas Industry - Part 1: Water-based Drilling Fluids".

[0071] 3. Performance Test Results

[0072] Table 1 Viscosity-average molecular weight of tackifiers

[0073] test sample viscosity average molecular weight (mPa s) example 1 2.22 x 10 6 ]] example 2 2.08 x 10 6 ]] comparative example 1 1.39 x 10 6 ]] comparative example 2 1.25 x 10 6 ]]> comparative example 3 1.21 x 10 6 ]] comparative example 4 1.33 x 10 6 ]]> comparative example 5 1.42 x 10 6 ]]> comparative example 6 1.68 x 10 6 ]]> comparative example 7 1.74 x 10 6 ]]> comparative example 8 2.02 x 10 6 ]]

[0074] Table 1 records the viscosity-average molecular weight of the samples from Examples 1-2 and Comparative Examples 1-8. It can be seen that among Examples 1-2, the sample prepared in Example 2 has a larger viscosity-average molecular weight. In Comparative Example 1, due to the absence of highly reactive branched monomer A, the molecular weight of the tackifier is smaller due to free radical polymerization of aqueous solution. Comparative Examples 2, 3, 4, and 6 correspond to the absence of SSS, DMAA, NVP, and DTAB monomers, respectively. It can be seen that the absence of monomers leads to a decrease in the molecular weight of the tackifier. This is because all four monomers are easy to polymerize and easily increase the molecular weight of the polymer. Comparative Examples 6 and 7 use two commercially available crosslinking agents to replace the highly reactive hyperbranched monomer, resulting in polymers with lower molecular weights. Comparative Example 8 uses the commercially available tackifier HE300, which has a relatively large viscosity-average molecular weight.

[0075] Table 2 Density 1.70 g / cm³ 3 Thickening properties of calcium chloride / calcium bromide brine after aging at 180℃ / 200℃

[0076]

[0077]

[0078] As can be seen from the test results in Table 2, compared with the composite brine completion fluid without added viscosifier, the apparent viscosity (AV), plastic viscosity (PV), and dynamic shear force (YP) of the completion fluid were significantly improved after adding the viscosifier prepared in Examples 1-2. Even after aging at 180℃ and 200℃, the viscosifying performance of the examples was still maintained, indicating that the viscosifier prepared in the examples has excellent high-temperature resistance. Among them, the completion fluid sample with the highest viscosity and the best performance was obtained after adding the viscosifier from Example 2.

[0079] In summary, the viscosity improver prepared by this invention still exhibits excellent viscosity improver properties after aging in a high-temperature (200℃) composite calcium salt (calcium chloride / calcium bromide) environment, which can enrich the development of high-temperature and high-density solids-free completion fluid technology.

Claims

1. A method for preparing a high-temperature resistant hyperbranched polymer tackifier for composite calcium salt water completion fluid, comprising the following steps: (1) preparing a high-reactivity branched monomer mixing γ-aminopropyl triethoxysilane, diethylene glycol and triethylene glycol, stirring until uniform, and then performing a reaction; after the reaction is completed, performing dialysis and freeze-drying to obtain the high-reactivity branched monomer; the mass ratio of the γ-aminopropyl triethoxysilane, diethylene glycol and triethylene glycol is 1:3-5:1-3; (2) preparing the high-temperature resistant hyperbranched polymer tackifier adding a salt-resistant monomer and the high-reactivity branched monomer prepared in step (1) into deionized water, and then adding an acrylamide monomer, a rigid cyclic monomer and a hydrophobic monomer to obtain a monomer solution; adjusting the pH value of the monomer solution, removing oxygen by nitrogen blowing, then increasing the temperature to a reaction temperature, adding an initiator, and initiating a polymerization reaction by heating; after the reaction is completed, adding ethanol to the obtained reaction solution to perform precipitation, and then performing filtration, vacuum drying and crushing to obtain the high-temperature resistant hyperbranched polymer tackifier for composite calcium salt water completion fluid; the salt-resistant monomer is 2-acrylamido-2-methylpropanesulfonic acid, sodium p-styrenesulfonate or sodium vinyl sulfonate; the acrylamide monomer is acrylamide, N,N-dimethyl acrylamide or N-isopropyl acrylamide; the rigid cyclic monomer is N-vinyl pyrrolidone; and the hydrophobic monomer is dimethyl ditetradecyl ammonium bromide, allyl polyethylene glycol or cetyl dimethyl allyl ammonium chloride; the mass ratio of the salt-resistant monomer, the high-reactivity branched monomer, the acrylamide monomer, the rigid cyclic monomer and the hydrophobic monomer is 5-7:0.2:4:1:0.

3.

2. The method of claim 1, wherein the method is characterized by: In step (1), the mass ratio of the γ-aminopropyl triethoxysilane, diethylene glycol and triethylene glycol is 1:4:

2.

3. The method of claim 1, wherein the method is characterized by: In step (1), the temperature of the reaction is 150-200℃, and the reaction time is 2-4h. The dialysis step is: placing the product obtained after the reaction into a dialysis bag, and dialyzing in deionized water for 24-48h; the molecular weight cut-off of the dialysis bag is 3500Da; the freeze-drying temperature is 0-5℃, and the freeze-drying time is 10-15h.

4. The method of claim 1, wherein the method is characterized by, In step (2), the allyl polyethylene glycol is APEG-800, APEG-1000, APEG-1200, APEG-1300, APEG-2000 or APEG-2200.

5. The method of preparing a high temperature resistant hyperbranched polymer viscosifier for use in a composite calcium salt water completion fluid according to claim 1, characterized in that, In step (2), the mass ratio of the salt-resistant monomer, the high-reactivity branched monomer, the acrylamide monomer, the rigid cyclic monomer and the hydrophobic monomer is 6:0.2:4:1:0.

3.

6. The method of preparing a high temperature resistant hyperbranched polymer viscosifier for composite calcium salt water completion fluids according to claim 1, characterized in that, In step (2), the mass ratio of the salt-resistant monomer and the deionized water is 1:4-10. In step (2), the pH value of the monomer solution is adjusted to 5-8; a 20-40% sodium hydroxide aqueous solution is used to adjust the pH value of the monomer solution.

7. The method of claim 1, wherein the method is characterized by: In step (2), the pH value of the monomer solution is adjusted to 6-7.

8. The method of claim 1, wherein the method is characterized by, The initiator in step (2) is potassium persulfate, ammonium persulfate, azobisisobutyronitrile, azobisisobutyramidine hydrochloride; the mass of the initiator is 0.01-0.2% of the total mass of the salt-resistant monomer, the high-reactivity branched monomer, the acrylamide monomer, the rigid cyclic monomer and the hydrophobic monomer.

9. The method of preparing a high temperature resistant hyperbranched polymer viscosifier for use in a composite calcium salt water completion fluid according to claim 1, characterized in that, The mass of the initiator in step (2) is 0.05-0.1% of the total mass of the salt-resistant monomer, the high-reactivity branched monomer, the acrylamide monomer, the rigid cyclic monomer and the hydrophobic monomer.

10. The method of preparing a high temperature resistant hyperbranched polymer viscosifier for use in a composite calcium salt water completion fluid according to claim 1, characterized in that, The reaction temperature in step (2) is 55-65℃, and the polymerization time is 3-5h. The ratio of the volume of the ethanol to the mass of the salt-resistant monomer is 15-50mL:1g; the temperature of the vacuum drying is 70-80℃, and the vacuum drying time is 8-10h.

11. A high temperature resistant hyperbranched polymer viscosifier for composite calcium salt water completion fluids, characterized in that, The method is prepared by using the preparation method in any one of claims 1-10.

12. The application of the high-temperature-resistant hyperbranched polymer tackifier for composite calcium salt water completion fluid in the composite calcium salt water completion fluid in claim 11; the concentration of the high-temperature-resistant hyperbranched polymer tackifier for composite calcium salt water completion fluid in the composite calcium salt water completion fluid is 10-15g / L; the composite calcium salt includes calcium chloride and calcium bromide.

Images