Fracturing cleanup aid and method of making same

Abstract

The application relates to the technical field of petroleum chemical industry, and discloses a fracturing cleanup aid and a preparation method thereof. The fracturing cleanup aid is obtained by reacting a di-glycidyl ether material, p-phenylenedi(1-piperazine) and an alkyl chloride. The cleanup aid has good surface activity, low surface tension of a solution, is beneficial to reducing capillary resistance, reducing the pressure of residual liquid flowback after fracturing, and improving cleanup rate and cleanup performance. The cleanup aid contains hydroxyl groups and quaternary ammonium salt groups, can form interaction with silicate substances in rocks, enter rock pores, destroy the oil film on the surface of the rocks, improve the surface wetting performance of the rocks, and further improve the flowback performance. The cleanup aid has good high-temperature resistance and does not contain fluorine elements, and is green and environment-friendly.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of petroleum chemical industry, in particular to a fracturing cleanup aid and a preparation method thereof. BACKGROUND

[0002] Fracturing fluid is a working fluid for fracturing reconstruction of oil and gas layers, but if the residual liquid of the fracturing fluid is not discharged from the formation in time, the oil and gas permeation and recovery rate will be affected, and the oil and gas layer will be polluted and damaged. Generally, a cleanup aid needs to be added to the fracturing fluid to promote the flowback of the residual liquid of the fracturing fluid by reducing the surface tension and interfacial tension and improving the flowability and permeability of the fracturing fluid.

[0003] Common cleanup aids include fluorocarbon, cationic surfactant and polyhydric alcohol. Although the fluorocarbon cleanup aid has excellent flowback performance, it is easy to cause secondary pollution to the formation. The patent with the publication number CN118185612B discloses an oil and gas field fracturing cleanup aid based on Gemini surfactant and a preparation method and application thereof. The fracturing cleanup aid compounded by the Gemini quaternary ammonium salt surfactant, chitosan and fluorine-containing surfactant can improve the flowback rate of the fracturing fluid, but the cleanup aid contains fluorine element and has great toxicity and pollution, and the cleanup aid is only resistant to 90 DEG C thermal aging and has poor high-temperature resistance. SUMMARY

[0004] The application solves the problems of poor cleanup flowback performance and temperature resistance of the conventional cationic surfactant cleanup aid, and does not contain fluorine element.

[0005] Technical scheme: A preparation method of a fracturing cleanup aid:

[0006] Step (1), a reaction solvent, diglycidyl ether with a mass ratio of (70-82):100 and p-phenylenediamine are added to a reaction bottle, and after stirring reaction, vacuum distillation is carried out, the product is washed with dichloromethane, and drying is carried out to obtain a cleanup aid precursor.

[0007] Step (2), a reaction solvent, the cleanup aid precursor with a mass ratio of 100:(26-38) and alkyl chloride are added to a reaction bottle, and after stirring reaction, vacuum distillation is carried out, the product is washed with petroleum ether, and drying is carried out to obtain the fracturing cleanup aid. The preparation reaction formula is as follows:

[0008] .

[0009] Preferably, the reaction solvent in step (1) is ethanol or tetrahydrofuran.

[0010] Preferably, the reaction temperature in step (1) is 70-80 DEG C, and the reaction time is 6-10 h.

[0011] Preferably, the diglycidyl ether in step (1) is ethylene glycol diglycidyl ether or 1,4-butanediol diglycidyl ether.

[0012] Preferably, the reaction solvent in step (2) is ethanol, isopropanol or N,N-dimethylformamide.

[0013] Preferably, the reaction temperature in step (2) is 75-110℃, and the reaction time is 24-48h.

[0014] Preferably, the alkyl chloride in step (2) has the structural formula of Cl-C a H 2a+1 , and a is any integer value in 12-18.

[0015] The application has the beneficial technical effects that: the diglycidyl ether material is subjected to ring-opening polymerization with p-phenylene bis(1-piperazine), the tertiary amine structure of the molecular chain is subjected to quaternary ammonium reaction with alkyl chloride, and the fracturing cleanup additive is obtained. The cleanup additive contains hydrophilic hydroxyl and quaternary ammonium salt groups, and hydrophobic benzene rings and alkyl long carbon chains, so that the cleanup additive has amphiphilicity, exhibits good surface activity, significantly reduces the surface tension of the solution, is beneficial to reducing capillary resistance and reducing the pressure of residual liquid flowback after fracturing, and thus improves the cleanup rate and cleanup performance.

[0016] The cleanup additive of the application contains hydroxyl, quaternary ammonium salt and other groups, can form hydrogen bonds, electrostatic interactions and the like with silicate substances in rocks, enter into rock pores, destroy the oil film on the surface of the rock, improve the surface wetting performance of the rock, make the formation tend to be water-wet, and further improve the flowback performance.

[0017] The cleanup additive of the application contains heat-resistant piperazine rings and benzene rings, has high structural stability, makes the molecular chain of the cleanup additive have good high-temperature resistance, and after high-temperature heat treatment, the cleanup additive still has high cleanup rate, and the cleanup additive does not contain fluorine elements, is green and environmentally friendly. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is the infrared spectrum of the fracturing cleanup additive of Example 1. DETAILED DESCRIPTION Example 1

[0019] (1) p-phenylene bis (1-piperazine) was prepared according to the method of the paper "Functionalised dithiocarbamate complexes: Complexes based on indoline, indole and substituted piperazine backbones - X-ray crystal structure of [Ni (S2CNC3H6C6H4) 2]" in the journal Inorganica Chimica Acta 363 (2010) 3222-3228, and the structural formula is .

[0020] (2) 60 mL of ethanol, 3.5 g of ethylene glycol diglycidyl ether, and 5 g (20.33 mmol) of p-phenylene bis (1-piperazine) were added to a reaction bottle, heated to 80°C, stirred for 6 h, and condensed refluxed during the reaction. The product was washed with dichloromethane and dried under reduced pressure to obtain a cleanup agent precursor.

[0021] (3) 200 mL of isopropyl alcohol, 10 g of the cleanup agent precursor, and 2.9 g of 1-chlorotetradecane were added to a reaction bottle, heated to 85°C, stirred for 36 h, and distilled under reduced pressure. The product was washed with petroleum ether and dried to obtain a cleanup agent for fracturing. According to the infrared spectrum of Figure 1 , the -OH absorption peak of the cleanup agent is located at 3347 cm -1 , the absorption peaks of the alkyl long-chain methyl and methylene are located at 2936 cm-1 and 2859 cm -1 , the characteristic peaks of the benzene ring skeleton are located at 1578 cm -1 to 1450 cm -1 , the characteristic peaks of the quaternary ammonium salt + N-C bond are located at 1415 cm -1 . Example 2

[0022] (1) 80 mL of tetrahydrofuran, 4 g of 1,4-butanediol diglycidyl ether, and 5 g of p-phenylene bis (1-piperazine) were added to a reaction bottle, heated to 75°C, stirred for 6 h, and condensed refluxed during the reaction. The product was washed with dichloromethane and dried under reduced pressure to obtain a cleanup agent precursor.

[0023] (2) 150 mL of N,N-dimethylformamide, 10 g of the cleanup agent precursor, and 2.6 g of 1-chlorododecane were added to a reaction bottle, heated to 110°C, stirred for 24 h, distilled under reduced pressure, washed with petroleum ether, and dried to obtain a cleanup agent for fracturing. Example 3

[0024] (1) To a reaction flask was added 80 mL of ethanol, 4.1 g of 1,4-butanediol diglycidyl ether, 5 g of p-phenylene bis(1-piperazine), heated to 70°C, stirred for 9 h with reflux condensation, distilled under reduced pressure, washed with dichloromethane, dried to obtain a cleanup additive precursor.

[0025] (2) To a reaction flask was added 200 mL of ethanol, 10 g of the cleanup additive precursor, 3.8 g of 1-chlorooctadecane, heated to 75°C, stirred for 48 h with reflux condensation, distilled under reduced pressure, washed with petroleum ether, dried to obtain a cleanup additive for fracturing. Example 4

[0026] (1) To a reaction flask was added 80 mL of ethanol, 3.5 g of ethylene glycol diglycidyl ether, 5 g of p-phenylene bis(1-piperazine), heated to 70°C, stirred for 10 h with reflux condensation, distilled under reduced pressure, washed with dichloromethane, dried to obtain a cleanup additive precursor.

[0027] (2) To a reaction flask was added 150 mL of N,N-dimethylformamide, 10 g of the cleanup additive precursor, 3.4 g of 1-chlorohexadecane, heated to 110°C, stirred for 24 h, distilled under reduced pressure, washed with petroleum ether, dried to obtain a cleanup additive for fracturing.

[0028] Comparative Example 1

[0029] Comparative Example 2

[0030] (1) To a reaction flask was added 60 mL of ethanol, 3.5 g of ethylene glycol diglycidyl ether, 1.79 g (20.33 mmol) of N,N'-dimethylethylenediamine (CAS No. 110-70-3), heated to 80°C, stirred for 6 h with reflux condensation, distilled under reduced pressure, washed with dichloromethane, dried to obtain a cleanup additive precursor.

[0031] (2) To a reaction flask was added 200 mL of isopropyl alcohol, 10 g of the cleanup additive precursor, 2.9 g of 1-chlorotetradecane, heated to 85°C, stirred for 36 h, distilled under reduced pressure, washed with petroleum ether, dried to obtain a cleanup additive for fracturing.

[0032] Comparative Example 3

[0033] (1) To a reaction flask was added 60 mL of ethanol, 3.5 g of ethylene glycol diglycidyl ether, 1.75 g (20.33 mmol) of piperazine, heated to 80°C, stirred for 6 h with reflux condensation, distilled under reduced pressure, washed with dichloromethane, dried to obtain a cleanup additive precursor.

[0034] (2) Add 200 mL of isopropyl alcohol, 10 g of the cleanup agent precursor, and 2.9 g of 1-chlorotetradecane into a reaction bottle, heat to 85°C, stir for 36 h, distill under reduced pressure, wash the product with petroleum ether, and dry to obtain the cleanup agent for fracturing.

[0035] Comparative Example 4

[0036] (1) Prepare N,N'-dimethyl-p-phenylenediamine according to the method in the journal J. Org. Chem. 2011, 76, 1180-1183, document “A Facile and Practical Copper Powder-Catalyzed, Organic Solvent- and Ligand-Free Ullmann Amination of Aryl Halides”, with the structural formula .

[0037] (2) Add 60 mL of ethanol, 3.5 g of ethylene glycol diglycidyl ether, and 1.75 g (20.33 mmol) of N,N'-dimethyl-p-phenylenediamine into a reaction bottle, heat to 80°C, stir for 6 h, condense reflux during the reaction, distill under reduced pressure, wash the product with dichloromethane, and dry to obtain the cleanup agent precursor.

[0038] (3) Add 200 mL of isopropyl alcohol, 10 g of the cleanup agent precursor, and 2.9 g of 1-chlorotetradecane into a reaction bottle, heat to 85°C, stir for 36 h, distill under reduced pressure, wash the product with petroleum ether, and dry to obtain the cleanup agent for fracturing.

[0039] Add the cleanup agent to deionized water to prepare a cleanup agent solution with a mass fraction of 0.2-0.6%. Measure the surface tension of the solution by a surface tension meter.

[0040] Table 1 Surface tension test

[0041]

[0042] Test the cleanup performance according to the method specified in the standard SY / T 5755-2016, and the mass fraction of the cleanup agent solution is 0.4%.

[0043] Place the cleanup agent solution in a sealed reaction kettle, heat at 100°C for 72 h, and test the cleanup performance after cooling.

[0044] Table 2 Cleanup performance test

[0045]

[0046] The surface tension of the cleanup agent solution prepared in Examples 1-4 is low, the cleanup rate is high, and the cleanup performance is good, and after high-temperature heat treatment, the cleanup agent still has a high cleanup rate and good high-temperature resistance, mainly because the cleanup agent contains hydrophilic hydroxyl and quaternary ammonium salt groups, and hydrophobic benzene rings and alkyl long carbon chains, so that the cleanup agent has amphiphilic properties and exhibits good surface activity, significantly reducing the surface tension of the solution, which is conducive to reducing capillary resistance and reducing the pressure of residual liquid flowback after fracturing, thereby improving the cleanup rate and cleanup performance. The cleanup agent contains hydroxyl groups, quaternary ammonium salts and other groups, which can form hydrogen bonds, electrostatic interactions and other interactions with silicate materials in the rock, enter the rock pores, destroy the oil film on the rock surface, improve the surface wetting properties, make the formation more water-wet, and further improve the flowback performance. The cleanup agent contains heat-resistant piperazine rings and benzene rings, has high structural stability, and the cleanup agent molecular chain has good high-temperature resistance, so that after high-temperature heat treatment, the cleanup agent has a high cleanup rate.

[0047] The cleanup agent precursor of Comparative Example 1 does not contain an alkyl quaternary ammonium salt structure, has low surface activity, a large surface tension of the solution, and poor cleanup performance.

[0048] The N,N'-dimethylethylenediamine of Comparative Example 2 and the cleanup agent prepared therefrom do not contain heat-resistant piperazine rings and benzene rings, have relatively low surface activity, and poor high-temperature resistance. The piperazine of Comparative Example 3 and the cleanup agent prepared therefrom do not contain benzene ring structures, and the N,N'-dimethyl-p-phenylenediamine of Comparative Example 4 does not contain piperazine ring structures, and the high-temperature resistance of the cleanup agents of both is poor.

Claims

1. A method for preparing a cleanup additive for fracturing, characterized by, The preparation method comprises: Step (1), adding a reaction solvent, a mass ratio of (70-82):100 of a diglycidyl ether, and p-phenylenediamine (1-piperazine) into a reaction bottle, stirring and reacting, then performing reduced pressure distillation, washing the product with dichloromethane, and drying to obtain a cleanup additive precursor; the diglycidyl ether is ethylene glycol diglycidyl ether or 1,4-butanediol diglycidyl ether; Step (2), adding a reaction solvent, a mass ratio of 100:(26-38) of the cleanup additive precursor, and an alkyl chloride into a reaction bottle, stirring and reacting, then performing reduced pressure distillation, washing the product with petroleum ether, and drying to obtain a cleanup additive for fracturing; The alkyl chloride has a structural formula of Cl-C a H 2a+1 , a is any integer value from 12 to 18.

2. The method of preparing a cleanup aid for fracturing according to claim 1, characterized in that, The reaction solvent in step (1) is ethanol or tetrahydrofuran.

3. The method of preparing a cleanup aid for fracturing according to claim 1, characterized in that, The reaction temperature in step (1) is 70-80°C, and the reaction time is 6-10h.

4. The method of preparing a cleanup aid for fracturing according to claim 1, characterized in that, The reaction solvent in step (2) is ethanol, isopropyl alcohol, or N,N-dimethylformamide.

5. The method of preparing a cleanup aid for fracturing according to claim 1, wherein The reaction temperature in step (2) is 75-110°C, and the reaction time is 24-48h.

6. A cleanup additive for fracturing obtained by the preparation method in any one of claims 1-5.

Images