Self-emulsifying resin curing agent, curing system and preparation method thereof

Abstract

The invention belongs to the field of oil field chemicals, and particularly relates to a self-emulsifying resin curing agent, a curing system and a preparation method thereof. The preparation method of the self-emulsifying epoxy curing agent comprises the following steps: (1) mixing an epoxy resin E-44 solution with triethylene tetramine, and reacting to obtain modified epoxy resin; and (2) adding 2, 3-epoxypropyl trimethyl ammonium chloride into the modified epoxy resin, and reacting to obtain the modified epoxy resin. The self-emulsifying curing agent disclosed by the invention is high in adaptability; the dosage is small, and the on-site construction process is simple; the toughness and corrosion resistance of the self-emulsifying resin curing system for the resin cement are remarkably improved.

Description

Technical Field

[0001] The invention belongs to the field of oilfield chemicals, and in particular relates to a self-emulsifying resin curing agent, a curing system and a preparation method thereof. Background Art

[0002] Cement slurry is injected between the annuli of the formation. After the cement slurry solidifies, it forms cement stone, which effectively isolates the formation and provides protection and support for the casing. The quality of cementing is related to the safety and efficiency of continued drilling and subsequent perforation, oil and gas production, and well repair. Microcracks are easily generated in the above operations, causing hazards such as interlayer crossflow. Therefore, it is necessary to improve the performance of cement stone and enhance the resistance of cement ring to complex stress.

[0003] Epoxy resin is a general term for compounds that contain two or more epoxy groups in one molecule and can form a three-dimensional cross-linked network of solidified products in the presence of appropriate chemical reagents. It has good adhesion, corrosion resistance, and high toughness of the cured product. However, there are still the following shortcomings in the use of epoxy resin in the field of cementing. First, epoxy resin is highly hydrophobic and has poor dispersion in cement slurry, which affects the performance of the slurry and cement stone. Secondly, due to the instability of epoxy resin emulsion, it needs to be prepared on the spot during cementing construction, which affects the efficiency of use.

[0004] In addition, epoxy resin is an important thermosetting polymer. As we all know, epoxy resin has various limitations. Without a curing agent, the desired mechanical properties cannot be obtained. The molecular structure and curing properties of the curing agent play a vital role in the mechanical properties of the cured film. Among the curing agents, small amine curing agents usually have high toxicity, short gel time, strict reactant ratio, high activity, and low CO 2 The curing agent prepared by waterborne epoxy resin and glycidyl tertiary carboxylic acid ester has greatly improved the water resistance and chemical resistance of the cured film. However, its self-emulsification ability is poor, which seriously limits its practical application.

[0005] In the early days, people usually used mechanical method and phase inversion method to prepare epoxy emulsion, that is, in the presence of emulsifier, high-speed stirring equipment was used to disperse non-water-soluble epoxy resin in water in the form of microparticles. These two methods are simple in process, but have many disadvantages, such as large particle size of the obtained emulsion, irregular particle shape and wide size distribution, poor emulsion stability, etc. When preparing water-based epoxy resin by physical method, in addition to the common emulsifier emulsification method and reactive emulsifier emulsification method, for low-viscosity epoxy resin, curing agent emulsification method can also be used. The so-called curing agent emulsification method is a method of using a substance that has the dual functions of emulsifying epoxy resin and curing epoxy resin, that is, a self-emulsifying curing agent to make epoxy resin water-based. Since epoxy resin itself is a thermoplastic resin, a curing agent is needed to make it a thermosetting resin during use. When using the curing agent emulsification method, the emulsifier and curing agent are combined into one, which can reduce the operation steps and do not need to consider the stability of the epoxy resin emulsion. When the emulsifier molecule contains molecular segments similar to those of the emulsified substance, the molecular interaction between the emulsifier and the emulsified substance can be increased, making the emulsification conditions milder.

[0006] Chinese invention patent application CN101649041A discloses a method for preparing a self-emulsifying waterborne epoxy resin curing agent, wherein triethylenetetramine and liquid epoxy resin CYD128 are used as raw materials, and the material molar ratio of triethylenetetramine: epoxy resin CYD128 is 1-2.2:1, and the epoxy resin CYD128-TETA adduct is obtained by synthesis reaction; then a mixed end-capping agent is added dropwise to the epoxy resin CYD128-TETA adduct, wherein the epoxy group in the mixed end-capping agent and the primary amine hydrogen in the epoxy resin CYD128-TETA adduct are in a stoichiometric ratio of 1:1, and then the secondary amine hydrogen of the product generated after the end-capping is neutralized with an organic acid to form a salt, and finally diluted with water. However, the curing agent obtained by this method has poor self-emulsification ability and is not suitable for resin cement.

[0007] In addition, the prior art also has the problem of brittleness of the cured epoxy resin film and unsatisfactory dispersion of the epoxy resin in aqueous solution. Summary of the invention

[0008] In order to solve the above problems, the present invention provides a self-emulsifying resin curing agent, a curing system and a preparation method thereof. The self-emulsifying resin curing system for resin cement of the present invention can resist dilution of aqueous solution in cement slurry to form a stable water dispersion system, has the advantages of strong corrosion resistance, high compressive strength, low cost, etc., and the formed resin cement can be widely used in cementing and plugging of oil and gas wells.

[0009] In order to achieve the above-mentioned purpose of the present invention, the specific technical solution adopted by the present invention is:

[0010] A self-emulsifying epoxy curing agent, the structural formula of the self-emulsifying epoxy curing agent is as follows:

[0011]

[0012] Preferably, the raw materials of the self-emulsifying epoxy curing agent include: epoxy resin E-44, triethylenetetramine and 2,3-epoxypropyltrimethylammonium chloride.

[0013] Preferably, the molar ratio of triethylenetetramine to epoxy resin E-44 is 2-2.8:1; the molar ratio of 2,3-epoxypropyltrimethylammonium chloride to triethylenetetramine is 0.5-1.2:1.

[0014] The present invention also relates to a method for preparing the self-emulsifying epoxy curing agent, comprising the following steps:

[0015] (1) mixing epoxy resin E-44 solution with triethylenetetramine, reacting to obtain a modified epoxy resin;

[0016] (2) Add 2,3-epoxypropyltrimethylammonium chloride to the modified epoxy resin and react to obtain the product.

[0017] Preferably, the solvent of the epoxy resin E-44 solution in step (1) is ethanol; the reaction temperature is 60-70° C., and the reaction time is 3-4 hours.

[0018] Preferably, the reaction temperature in step (2) is 65-75° C., and the reaction time is 2-3 h.

[0019] Preferably, both step (1) and step (2) are performed under a nitrogen environment.

[0020] When epoxy resin is emulsified, active hydrogen is needed to attack the epoxy group to make it solidify, and the active hydrogen is generally provided by amine compounds, so the current emulsification curing agent is generally epoxy-amine compounds. Among them, the amine compound is generally a polyethylene polyamine containing multiple active hydrogens. In addition to two primary amine groups at both ends, the polyethylene polyamine also contains several secondary amine groups, which provide reactive groups for the subsequent cross-linking of the epoxy resin. Therefore, the present invention selects TETA modified epoxy resin and EPTAC as the end-capping agent.

[0021] The present invention also relates to a self-emulsifying resin curing system for resin cement, wherein the self-emulsifying resin curing system comprises the self-emulsifying epoxy curing agent.

[0022] Preferably, the self-emulsifying resin curing system further comprises epoxy resin E-44 and a cement slurry system.

[0023] Preferably, the mass ratio of the self-emulsifying curing agent to the epoxy resin E-44 is 1-2:50.

[0024] Preferably, the raw materials of the cement slurry system include cement, an expansion agent, a fluid loss reducer, a dispersant, a retarder, a defoamer and water.

[0025] Preferably, the addition amounts of the expansion agent, fluid loss agent, dispersant, retarder and defoamer are 1.5-2.5%, 2-3%, 0.2-0.8%, 0.5-0.9% and 0.3-0.4% of the cement mass respectively; and the mass ratio of water to cement is 0.4-0.5:1.

[0026] The present invention also relates to a method for preparing the self-emulsifying resin curing system, comprising the following steps:

[0027] (1) mixing a self-emulsifying curing agent with epoxy resin E-44 and stirring to obtain an epoxy resin emulsion;

[0028] (2) Mix the epoxy resin emulsion and the cement slurry system and stir to obtain the product.

[0029] Preferably, the mass ratio of the epoxy resin emulsion to the cement slurry system in step (2) is 1:8-12.

[0030] Preferably, the stirring temperature in step (1) is 20-30° C., the stirring speed is 3800-4200 r / min, and the stirring time is 10-20 s.

[0031] Preferably, the stirring temperature in step (2) is 20-30° C., the stirring speed is 11000-13000 r / min, and the stirring time is 30-40 s.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The self-emulsifying resin curing system of the present invention has strong adaptability;

[0034] (2) The self-emulsifying resin curing system of the present invention has a small addition amount and a simple on-site construction process;

[0035] (3) The toughness and corrosion resistance of the self-emulsifying resin curing system for resin cement of the present invention are significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is the infrared spectrum of the self-emulsifying epoxy curing agent prepared in Example 1. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention are further clearly described. The described embodiments are only a part of the present invention and are used to explain the present invention but not to limit the present invention. Therefore, other embodiments obtained by other technicians in the field without creative work all belong to the protection scope of the present invention.

[0038] Epoxy resin E-44, model 6101, purchased from Guangzhou Changhong Chemical Co., Ltd.;

[0039] Jiahua G-grade cement (JHG) was purchased from Henan Qingdu Building Materials Co., Ltd.;

[0040] Expansion agent, model: BS500, purchased from Henan Qingdu Building Materials Co., Ltd.;

[0041] Fluid loss reducer, model: BS100T, purchased from Henan Qingdu Building Materials Co., Ltd.;

[0042] Dispersant, model: BS300, purchased from Henan Qingdu Building Materials Co., Ltd.;

[0043] Retarder, model: BS200R, purchased from Henan Qingdu Building Materials Co., Ltd.;

[0044] Defoamer, model BP-1B, purchased from Henan Qingdu Building Materials Co., Ltd.;

[0045] The reagents not particularly described in the following examples are all conventional reagents in the art and are commercially available.

[0046] Example 1

[0047] 1. Self-emulsifying epoxy curing agent:

[0048] Dissolve epoxy resin E-44 in ethanol. In a nitrogen environment, gradually add the epoxy resin E-44 solution to triethylenetetramine. The addition takes 1 hour. The molar ratio of triethylenetetramine to epoxy resin E-44 is 2.4:1. React at 60°C for 3 hours.

[0049] Then, 2,3-epoxypropyltrimethylammonium chloride was added dropwise at 65°C, and the molar ratio of 2,3-epoxypropyltrimethylammonium chloride to triethylenetetramine was 1.2:1. The reaction was continued at 70°C for 2h to obtain a self-emulsifying epoxy curing agent. The infrared spectrum of the curing agent is shown in FIG. Figure 1 shown.

[0050] 2. Self-emulsifying resin curing system for resin cement:

[0051] The self-emulsifying curing agent and epoxy resin E-44 were mixed in a mass ratio of 1:50, and stirred at 4000r / min for 15s at 25°C to obtain an epoxy resin emulsion, and then the epoxy resin emulsion was mixed with a cement slurry system in a mass ratio of 1:8, and stirred at 12000r / min for 35s to obtain a self-emulsifying resin curing system for resin cement. (The composition of the cement slurry system is: Jiahua G-grade cement (JHG), 2% expansion agent, 2.5% fluid loss agent, 0.5% dispersant, 0.75% retarder, 0.375% defoamer and water, wherein the mass ratio of water to cement is 0.44.)

[0052] Example 2

[0053] 1. Self-emulsifying epoxy curing agent:

[0054] Dissolve epoxy resin E-44 in ethanol. In a nitrogen environment, gradually add epoxy resin E-44 to triethylenetetramine. The addition takes 1 hour. The molar ratio of triethylenetetramine to epoxy resin E-44 is 2.5:1. React at 70°C for 4 hours.

[0055] Then, 2,3-epoxypropyltrimethylammonium chloride was added dropwise at 75° C., and the molar ratio of 2,3-epoxypropyltrimethylammonium chloride to triethylenetetramine was 1.3:1. The reaction was carried out at 75° C. for 3 hours to obtain a self-emulsifying epoxy curing agent.

[0056] 2. Self-emulsifying resin curing system for resin cement:

[0057] The self-emulsifying curing agent and epoxy resin E-44 were mixed in a mass ratio of 1.5:50, and stirred at 3800r / min for 20s at 28°C to obtain an epoxy resin emulsion, and then the epoxy resin emulsion was mixed with a cement slurry system in a mass ratio of 1:10, and stirred at 11000r / min for 40s to obtain a self-emulsifying resin curing system for resin cement. (The composition of the cement slurry system is: Jiahua G-grade cement (JHG), 1.5% expansion agent, 2% fluid loss agent, 0.3% dispersant, 0.5% retarder, 0.3% defoamer and water, wherein the mass ratio of water to cement is 0.4.)

[0058] Example 3

[0059] 1. Self-emulsifying epoxy curing agent:

[0060] Dissolve epoxy resin E-44 in ethanol. In a nitrogen environment, gradually add epoxy resin E-44 to triethylenetetramine. The addition takes 1 hour. The molar ratio of triethylenetetramine to epoxy resin E-44 is 2.6:1. React at 65°C for 4 hours.

[0061] Then, 2,3-epoxypropyltrimethylammonium chloride was added dropwise at 70° C., and the molar ratio of 2,3-epoxypropyltrimethylammonium chloride to triethylenetetramine was 1.4:1. The reaction was carried out at 70° C. for 3 hours to obtain a self-emulsifying epoxy curing agent.

[0062] 2. Self-emulsifying resin curing system for resin cement:

[0063] The self-emulsifying curing agent and epoxy resin E-44 were mixed in a mass ratio of 2:50, and stirred at 4200r / min for 10s at 30°C to obtain an epoxy resin emulsion, and then the epoxy resin emulsion was mixed with a cement slurry system in a mass ratio of 1:12, and stirred at 13000r / min for 30s to obtain a self-emulsifying resin curing system for resin cement. (The composition of the cement slurry system is: Jiahua G-grade cement (JHG), 2.5% expansion agent, 3% fluid loss agent, 0.8% dispersant, 0.9% retarder, 0.4% defoamer and water, wherein the mass ratio of water to cement is 0.5.)

[0064] Comparative Example 1

[0065] 1. Self-emulsifying epoxy curing agent:

[0066] Dissolve epoxy resin E-44 in ethanol. In a nitrogen environment, gradually add the epoxy resin E-44 solution to triethylenetetramine. The addition takes 1 hour. The molar ratio of triethylenetetramine to epoxy resin E-44 is 2.4:1. React at 60°C for 3 hours.

[0067] Then, a mixed end-capping agent (a mixed solution of butyl glycidyl ether and phenyl glycidyl ether) was added dropwise at 65°C, wherein the mass ratio of butyl glycidyl ether to phenyl glycidyl ether was 1:2, and the stoichiometric ratio of the epoxy group in the mixed end-capping agent to the primary amine hydrogen in the TETA-modified epoxy resin was 1:1. The mixture was reacted at 70°C for 2h to obtain a self-emulsifying epoxy curing agent.

[0068] 2. The preparation method of the self-emulsifying resin curing system for resin cement is the same as that in Example 1.

[0069] Comparative Example 2

[0070] 1. Self-emulsifying epoxy curing agent: commercially available product, model: RS-610, purchased from Nanjing Qinghai Trading Co., Ltd.

[0071] 2. The preparation method of the self-emulsifying resin curing system for resin cement is the same as that in Example 1.

[0072] Effect test

[0073] The evaluation of the self-emulsifying resin curing system for resin cement was carried out with reference to the standard GB / T 1771 / 2007. The basic performance evaluation was carried out and the test results are shown in Table 1.

[0074] Dispersion effect in water: Add the self-emulsifying resin curing agent dropwise into the aqueous solution and observe whether the self-emulsifying curing agent aggregates and settles in the aqueous solution.

[0075] Emulsion particle size test: The particle size of the self-emulsifying resin curing agent was tested using a laser scattering system (BI-200SM).

[0076] Compressive strength test: The resin cement with self-emulsifying curing agent was cured in a standard core mold for 24 hours, and then the compressive strength was measured using a universal testing machine. 2 The compressive strength is measured after corrosion in a high temperature and high pressure corrosion apparatus, and then the compressive strength reduction rate is obtained.

[0077] Table 1 Performance test of self-emulsified resin curing system

[0078]

[0079] The above detailed description is a specific description of one feasible embodiment of the present invention. The embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or modification that does not deviate from the present invention should be included in the scope of the technical solution of the present invention.

Claims

1. A self-emulsifying epoxy curing agent, characterized in that: The structural formula of the self-emulsifying epoxy curing agent is as follows:

2. The self-emulsifying epoxy curing agent according to claim 1, characterized in that The raw materials of the self-emulsifying epoxy curing agent include: epoxy resin E-44, triethylenetetramine and 2,3-epoxypropyltrimethylammonium chloride.

3. The self-emulsifying epoxy curing agent according to claim 2, characterized in that The molar ratio of the triethylenetetramine to the epoxy resin E-44 is 2-2.8:1; the molar ratio of the 2,3-epoxypropyltrimethylammonium chloride to the triethylenetetramine is 0.5-1.2:

1.

4. A method for preparing the self-emulsifying epoxy curing agent according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) mixing epoxy resin E-44 solution with triethylenetetramine, reacting to obtain a modified epoxy resin; (2) Add 2,3-epoxypropyltrimethylammonium chloride to the modified epoxy resin and react to obtain the product.

5. The preparation method according to claim 4, characterized in that: The solvent of the epoxy resin E-44 solution in step (1) is ethanol; the reaction temperature is 60-70° C., and the reaction time is 3-4 hours.

6. The preparation method according to claim 4, characterized in that: The reaction temperature in step (2) is 65-75° C., and the reaction time is 2-3 h.

7. The preparation method according to claim 4, characterized in that: Both step (1) and step (2) are performed under a nitrogen environment.

8. A self-emulsifying resin curing system for resin cement, characterized in that: The self-emulsifying resin curing system comprises the self-emulsifying epoxy curing agent described in any one of claims 1 to 3 or the self-emulsifying epoxy curing agent prepared by the preparation method described in any one of claims 4 to 7.

9. The self-emulsifying resin curing system for resin cement according to claim 8, characterized in that: The self-emulsifying resin curing system also includes epoxy resin E-44 and cement slurry system.

10. The self-emulsifying resin curing system according to claim 9, characterized in that: The mass ratio of the self-emulsifying curing agent to the epoxy resin E-44 is 1-2:

50.

11. The self-emulsifying resin curing system according to claim 9, characterized in that: The raw materials of the cement slurry system include cement, expansion agent, fluid loss reducer, dispersant, retarder, defoamer and water.

12. The self-emulsifying resin curing system according to claim 11, characterized in that: The addition amounts of the expansion agent, fluid loss reducer, dispersant, retarder and defoamer are 1.5-2.5%, 2-3%, 0.2-0.8%, 0.5-0.9% and 0.3-0.4% of the cement mass respectively; the mass ratio of water to cement is 0.4-0.5:

1.

13. A method for preparing the self-emulsifying resin curing system according to any one of claims 8 to 12, characterized in that: The following steps are involved: (1) mixing a self-emulsifying curing agent with epoxy resin E-44 and stirring to obtain an epoxy resin emulsion; (2) Mix the epoxy resin emulsion and the cement slurry system and stir to obtain the product.

14. The method for preparing the self-emulsifying resin curing system according to claim 13, characterized in that: The mass ratio of the epoxy resin emulsion to the cement slurry system in step (2) is 1:8-12.

15. The method for preparing the self-emulsifying resin curing system according to claim 14, characterized in that: The stirring temperature in step (1) is 20-30° C., the stirring speed is 3800-4200 r / min, and the stirring time is 10-20 s.

16. The method for preparing the self-emulsifying resin curing system according to claim 14, characterized in that: The stirring temperature in step (2) is 20-30° C., the stirring speed is 11000-13000 r / min, and the stirring time is 30-40 s.

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