CN109251737B - Epoxy-phenolic aldehyde system water plugging agent for oil and gas field exploitation - Google Patents

Abstract

The invention discloses an epoxy-phenolic aldehyde system water shutoff agent used for oil-gas field exploitation, which adopts a novel water shutoff agent consisting of epoxy resin as a resin matrix, linear phenolic aldehyde resin as a curing agent, imidazole type accelerant and alcohols and ketones as migratory diluents. The migratory diluent can greatly reduce the viscosity of the water shutoff agent and ensure the transportability of the water shutoff agent; upon contact with formation water, the migratable diluent migrates into the aqueous phase, while the other components of the system settle to the bottom of the aqueous phase, achieving effective solidification. The addition of the migratable diluent can reduce the adverse effect of the diluent on the curing process and the performance of the cured product, thereby realizing the adjustable curing time and ensuring the mechanical strength of the cured product. The water plugging agent disclosed by the invention has the characteristics of low viscosity, good pouring fluidity, wide application temperature range, adjustable curing speed and high strength after curing, and still has excellent plugging performance in high-temperature, high-salt, acidic and alkaline environments.

Description

A kind of epoxy-phenolic system water blocking agent used in oil and gas field exploitation

technical field

The invention relates to a water-blocking agent used in the exploitation process of oil and gas fields, in particular to an epoxy-phenolic system water-blocking agent which is used in harsh underground environment of oil and gas field exploitation.

Background technique

In the process of oil and gas field exploitation, some oil and gas wells have premature water breakthrough or flooding due to channeling of water layers, bottom water coning or injection water, and edge water inrush. In order to remove or reduce water flooding, control the flow of water in the water-producing layer, and improve oil and gas recovery, water-blocking agents are usually used to block the water-producing sections of production wells or injection wells. Water production in oil and gas fields is a common problem. Water blocking agents are the main means to solve this problem at present, and also an important means to improve oil and gas recovery and economic benefits. The water-blocking agents used in the early days, that is, the traditional water-blocking agents mainly include cement-type water-blocking agents and precipitation-type water-blocking agents. The effluent water is blocked in the cracks entering into the effluent, which restricts the enhancement of oil and gas recovery by water injection. In order to overcome the shortage of cement-based water-blocking agents and precipitation-based water-blocking agents, polymer gel-based water-blocking agents were developed later. Although polymer gel water plugging agents can overcome the shortage of cement water plugging agents and precipitation water plugging agents, the strength of polymer gel water plugging agents is low, and it is difficult to achieve ideal conditions in harsh downhole environments. water blocking effect. Therefore, it is necessary to provide a water plugging agent with good heat resistance, high strength, large performance adjustment space, and good water plugging effect in the harsh downhole environment, so as to solve the problem of water-bearing oil and gas wells. The problem of plugging of water layers.

SUMMARY OF THE INVENTION

In view of the deficiencies of the water-blocking agent used in the exploitation of oil and gas fields in the prior art, the purpose of the present invention is to provide a novel epoxy-phenolic system water-blocking agent that can be applied to the harsh underground environment, so as to solve the problem of water-bearing oil and gas wells segment blocking problem.

Aiming at the blocking problem of the production well water layer in the oil and gas exploitation to be solved by the present invention, the novel epoxy resin water blocking agent provided by the present invention adopts epoxy resin as resin matrix, novolak resin as curing agent, and Imidazoles are used as accelerators, and alcohols and ketones are used as diluents to form an epoxy-phenolic curing system, so that the water blocking agent has the properties of low viscosity, wide applicable temperature range, adjustable curing speed and high strength after curing. It has good perfusion fluidity and wider applicability, and still has excellent plugging effect in complex and harsh conditions, such as high temperature, high salt, acid and alkaline environments.

The epoxy-phenolic system water-blocking agent for oil and gas field exploitation provided by the present invention, its specific technical scheme is constituted, and the raw material components include, in parts by mass, 45-80 parts of bisphenol F or/and bisphenol A epoxy resin , Novolac resin 10-50, imidazole accelerator 0.01-0.05, migratory diluent 10-60.

In the above epoxy-phenolic system water blocking agent of the present invention, the content of the bisphenol F or/and bisphenol A epoxy resin is related to the time when the water blocking agent is injected into the gel, and the gel time of the water blocking agent is related to the downhole It is related to the temperature. The higher the temperature, the faster the gelation, and vice versa. Therefore, the content of bisphenol F or/and bisphenol A epoxy resin should be adjusted according to the downhole ambient temperature. Can be less, on the contrary, the content can be higher. For the component epoxy resins, bisphenol F epoxy resin or bisphenol A epoxy resin can be used alone, or bisphenol F epoxy resin and bisphenol A epoxy resin can be used simultaneously. For the latter, bisphenol F epoxy resin and bisphenol A epoxy resin can be in any ratio, but preferably, the amount of bisphenol F epoxy resin is not more than 45 parts, and the amount of bisphenol A epoxy resin is not more than 45 parts. 65 servings. The bisphenol F epoxy resin and bisphenol A epoxy resin are preferably bisphenol F oxygen resin and bisphenol A epoxy resin with an epoxy equivalent weight of 150-230 g/mol.

In the epoxy-phenolic system water blocking agent used in the above-mentioned oil and gas field exploitation of the present invention, the content of the mobile diluent is related to the viscosity of the water blocking agent, and the more the content of the mobile diluent is, the lower the viscosity of the water blocking agent is. , is conducive to the perfusion of the water blocking agent, and the viscosity of the water blocking agent is related to the perfusion environment temperature of the water blocking agent. The higher the perfusion environment temperature is, the lower the viscosity of the water blocking agent is. Therefore, the content of the migratory diluent should be adjusted according to the ambient temperature of the water plugging agent. The mobile diluent is preferably methanol, ethanol, acetone, butanone and n-butanol.

The migratory diluent of the epoxy-phenolic system water blocking agent used in oil and gas field exploitation provided by the invention can not only greatly reduce the viscosity of the system, but also ensure that the epoxy-phenolic resin system water blocking agent has good transportability; After the water plugging agent contacts the formation water, the migratory diluent will migrate into the water phase, while other components in the system will settle to the bottom of the water layer to achieve effective solidification. The addition of the migratory diluent can not only reduce the adverse effect of the diluent on the curing process and the properties of the cured product, so as to realize the adjustable curing time, and ensure the mechanical strength of the cured product.

In order to prove that the epoxy-phenolic system water-blocking agent used in oil and gas field exploitation provided by the present invention has excellent performance, the inventor conducted an underground environment simulation experiment on it, namely pouring the resin slurry obtained by fully mixing the components of the water-blocking agent into Put it into a hydrothermal kettle with water, and after sealing, carry out curing experiments at different temperature points in the range of 100℃-150℃, all of which can achieve gel curing, and the gel time can be adjusted within 0.5-9 hours. That is, it can be applied to the plugging of the water outlet layer of oil and gas wells where the downhole ambient temperature is in the range of 100℃-150℃.

The water blocking agent system provided by the invention has the characteristics of low viscosity, wide applicable temperature range, adjustable curing speed, high strength after curing, good perfusion fluidity and wide applicability, and can be used in complex and severe conditions, such as high temperature, high salt, acidity, etc. , still has excellent performance in an alkaline environment. Compared with the existing water blocking agent, it has the following very prominent advantages and technical effects in general:

1. The water plugging agent of the present invention has a very low viscosity before curing, and has excellent fluidity, which is beneficial to the perfusion and transportation of the water plugging agent, and can meet the plugging of water from deep wells.

2. The water blocking agent of the present invention can be solidified at 100-150° C., and has the characteristics that the gel time can be adjusted within 0.5-9 hours, and has wide applicability.

3. The water blocking agent of the present invention can still be cured well under severe conditions such as high salt, high water content, acidity and alkalinity, and the cured product has high compressive strength and excellent mechanical properties.

Description of drawings

Fig. 1 is the change curve of the viscosity of the resin system water blocking agent of the present invention with the type and amount of diluent under the condition that the addition amounts of bisphenol A epoxy resin and phenolic resin are 45 parts and 30 parts respectively.

Fig. 2 is the change curve of the viscosity of the resin system water blocking agent according to the present invention with the type and amount of diluent under the condition that the addition amounts of bisphenol F epoxy resin and phenolic resin are 45 parts and 30 parts respectively.

Fig. 3 is the change curve of the viscosity of the water blocking agent of the resin system of the present invention with the addition amount of phenolic resin under the condition that the addition amounts of bisphenol A epoxy resin and diluent methanol are 45 parts and 30 parts respectively.

Fig. 4 is the change curve of the viscosity of the water blocking agent in the resin system of the present invention with the addition amount of phenolic resin under the condition that the addition amounts of bisphenol F epoxy resin and diluent methanol are 45 parts and 30 parts respectively.

It can be seen from Figure 1 to Figure 4 that the viscosity of the system increases with the increase of the addition amount of phenolic resin regardless of whether bisphenol A type or bisphenol F type epoxy resin is used. But by adding a diluent, the viscosity of the system can be greatly reduced. Among them, methanol and acetone have more excellent dilution effect than other alcohols and ketones due to their extremely low viscosity and excellent solubility in epoxy systems. Through adjustment, the viscosity of the slurry can be reduced to below 50 mPa.s, which reflects the excellent fluidity of the resin system.

Figure 5. Curing time curve of water blocking agent formulations with different accelerator addition amounts at different temperatures.

As shown in Figure 5, at 110-130 °C, as the temperature increases, the amount of accelerator required to achieve the same curing time gradually decreases, but the difference is not large; when the temperature rises to 140 °C and 150 °C, the same curing time is achieved. The amount of accelerator required for curing time decreases sharply, and the difference between the amount of accelerator required for different curing times is getting smaller and smaller, indicating that at a high temperature of 150 °C, the precise control of curing time is greatly increased, but still It can be guaranteed to complete curing within 3-7h.

Figure 6-1 is the change curve of curing time of the water plugging agent in different brines; Figure 6-2 is the change curve of the curing time of the water plugging agent of the present invention under different pH values.

As shown in Figure 6-1 and Figure 6-2, in the saturated solution of CaCl ₂ , MgCl ₂ , and MgSO ₄ , the curing time of the water blocking agent of the present invention does not change significantly compared with that in pure water. This result shows that the above brine has no obvious effect on the curing time of the water plugging agent, indicating that the water plugging agent can still be effectively cured in salt water. While the saturated NaHCO ₃ solution is alkaline, the epoxy ring-opening is easier to carry out, and the curing time of the system is shortened to a certain extent.

The effect of pH value on the curing time of the water plugging agent is more obvious. When the pH is 5-7, the curing time of the system has no obvious change; when the pH is lowered to 4-5, the curing time of the system is significantly prolonged. This is because the acidic environment will weaken the accelerating effect of imidazole compounds on the curing reaction, thereby prolonging the curing time. However, when the pH is 7-8, the curing time of the system is significantly shortened because the epoxy ring opening is more likely to occur under alkaline conditions.

Figure 7 is the DMA test chart of the water blocking agent samples after curing with bisphenol F epoxy resin as the matrix and adding different amounts of phenolic resin.

Figure 8. DMA test chart of water blocking agent samples after curing with bisphenol F epoxy resin as matrix and adding different amounts of methanol diluent.

As shown in Figure 7, the glass transition temperature of the resin water blocking agent showed a trend of first increasing and then decreasing with the increase of the amount of phenolic resin added. When the ratio of epoxy resin to phenolic resin was 45:30, the glass transition temperature of the resin sample reached the highest. When the proportion of epoxy resin and phenolic resin added is lower than 45:30, the amount of phenolic resin is excessive; otherwise, the epoxy resin is excessive. In both cases, the crosslinking density of the cured resin product will decrease to a certain extent, which in turn leads to a decrease in the glass transition temperature.

As shown in Figure 8, the higher the amount of diluent added, the lower the glass transition temperature of the resin sample. This is because in the presence of a large amount of diluent, after the system is mixed with water, although part of the diluent will be extracted by water, in the presence of a large amount of diluent, some of the diluent will still remain in the system. In the resin cross-linked network, the density of the resin cross-linked network decreases, resulting in a decrease in the glass transition temperature.

Figure 9-1 is the compression curve of the water plugging agent of the present invention under different salt water; Figure 9-2 is the compression curve of the water plugging agent of the present invention under different pH values.

Figure 10. Compression curves of resins after curing in environments with different water content.

As shown in Figure 9-1 and Figure 9-2, the compressive strength of the samples cured in different brines did not change significantly compared with the samples cured in pure water, indicating the excellent salt resistance of the resin system. The properties of the samples cured in a weak acid environment (pH=5-7) did not change significantly compared to the samples cured in pure water. When the pH was lowered to 4-5, the resin strength decreased to a certain extent. This is because the acidic environment will weaken the promoting effect of imidazole compounds on the curing reaction, which will prolong the curing reaction time and cause the epoxy resin to be incompletely cured, thereby reducing the performance of the resin after curing; in a weak alkaline environment The compressive strength of the cured samples increased to a certain extent. This is because the alkaline environment can promote epoxy curing, improve the degree of reaction, and then improve the mechanical properties of the cured product.

As shown in Figure 10, the mechanical properties of the samples cured in environments with different water contents showed large differences. The compressive strength of the resin increases with increasing moisture content in the curing environment. After the water content reaches a certain value, the compressive strength stabilizes at a certain value and does not increase. Because the diluent in the system is miscible with water. After the resin system is mixed with water, part of the diluent will be extracted by the water. On the contrary, the epoxy and phenolic parts of the resin system are insoluble in water and will sink to the lower layer of the mixed solution. When the water content is low, only a small part of the diluent is extracted into the water. At this time, most of the diluent remains in the epoxy novolac system, which in turn results in a decrease in the density of the cross-linked network after curing, resulting in a decrease in the strength of the material. When the water content is high, most of the diluent is extracted into the water, thus ensuring that the epoxy novolac system can form a dense cross-linked network, reflecting high strength.

Figure 11 is a resin compression curve after curing and aging for one month in an aqueous environment with a volume fraction of 15% hydrogen sulfide.

As shown in Figure 11, the shrinkage curves of the resins cured and aged for one month in an aqueous environment with a volume fraction of 15% hydrogen sulfide are significantly different from those of the unaged samples. This is due to the increased brittleness of resin samples after aging in high temperature, high sulfur, and aqueous environments. Some degree of fragmentation occurs at the edges during compression, but the bulk of the sample remains intact, resulting in the appearance of irregular compression curves. Nevertheless, the final complete crushing strength of the system can still reach 70MPa, showing excellent aging resistance.

Detailed ways

The present invention will be specifically described by the following examples. It is necessary to point out that this example is only used to further illustrate the present invention, and should not be construed as a limitation on the protection scope of the present invention. Some non-essential improvements and adjustments have been made to the content.

The following relevant tests were carried out to the resin water blocking agent samples prepared in the following examples according to the following methods:

1. Viscosity test

An AR2000 torque rheometer was used to test the viscosity of the slurry at 20°C-50°C.

2. Curing time test

Curing time test of water blocking agent formulations with different accelerator additions at different temperatures: Pour the resin slurry into 6 hydrothermal kettles, place them in an environment of 100-150 °C to cure, and turn on a hydrothermal tank every hour. Observe the solidification of the slurry in the kettle. When the resin cannot flow, it is regarded as solidified.

3. Dynamic mechanical test

The samples were subjected to dynamic mechanical testing in three-point bending mode using DMA Q800 (TA instruments). The frequency was set to 1 Hz, and the heating rate was set to 3 °C/min.

4. Mechanical properties test

The compressive properties of the samples were tested by a universal test machine (Instron 5567, US). The test method refers to GBT 1041-2008.

In the following embodiments, the parts and percentages of each constituent component, unless otherwise specified, are the parts by mass and the percentage by mass.

Example 1

A total of 45 parts of bisphenol F epoxy resin and 30 parts of novolac resin were melted and mixed, 0.03 part of imidazole accelerator and 30 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. The resin slurry was poured into a hydrothermal kettle filled with distilled water, sealed and cured at 130°C.

Performance test: The viscosity of the epoxy resin slurry prepared in Example 1 at 25° C. was 48.5 mPa.s, the curing time was 5 h, and the compressive strength was 85 MPa.

Example 2

A total of 45 parts of bisphenol F epoxy resin and 30 parts of novolac resin were melt-mixed, 0.01 part of imidazole accelerator and 30 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. The resin slurry was poured into a hydrothermal kettle filled with distilled water, sealed and cured at 130°C.

Performance test: The viscosity of the epoxy resin slurry prepared in Example 2 at 25° C. was 48.5 mPa.s, the curing time was 7 h, and the compressive strength was 82 MPa.

Example 3

A total of 45 parts of bisphenol F epoxy resin and 30 parts of novolac resin were melt-mixed, 0.05 part of imidazole accelerator and 30 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. The resin slurry was poured into a hydrothermal kettle filled with distilled water, sealed and cured at 130°C.

Performance test: The measured viscosity of the epoxy resin slurry prepared in Example 3 at 25° C. was 48.5 mPa.s, the curing time was 3 h, and the compressive strength was 90 MPa.

Example 4

A total of 45 parts of bisphenol F epoxy resin and 30 parts of novolac resin were melted and mixed, 0.03 part of imidazole accelerator and 30 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. The resin slurry was poured into a hydrothermal kettle filled with distilled water, sealed and cured at 110°C.

Performance test: The measured viscosity of the epoxy resin slurry prepared in Example 4 at 25° C. is 48.5.mPa.s, the curing time is 7h, and the compressive strength is 72MPa.

Example 5

A total of 45 parts of bisphenol F epoxy resin and 30 parts of novolac resin were melt-mixed, 0.01 part of imidazole accelerator and 30 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. The resin slurry was poured into a hydrothermal kettle filled with distilled water, sealed and cured at 150°C.

Performance test: The viscosity of the epoxy resin slurry prepared in Example 5 at 25° C. was 48.5 mPa.s, the curing time was 3 h, and the compressive strength was 88 MPa.

Example 6

A total of 45 parts of bisphenol F epoxy resin and 30 parts of novolac resin were melt-mixed, 0.03 part of imidazole accelerator and 10 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. The resin slurry was poured into a hydrothermal kettle filled with distilled water, sealed and cured at 130°C.

Performance test: The viscosity of the epoxy resin slurry prepared in Example 6 at 25° C. was 118.4 mPa.s, the curing time was 4 h, and the compressive strength was 90 MPa.

Example 7

A total of 45 parts of bisphenol F epoxy resin and 30 parts of novolac resin were melted and mixed, 0.03 part of imidazole accelerator and 50 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. The resin slurry was poured into a hydrothermal kettle filled with distilled water, sealed and cured at 130°C.

Performance test: The viscosity of the epoxy resin slurry prepared in Example 7 at 25°C was 28.1 mPa.s, the curing time was 6h, and the compressive strength was 76MPa.

Example 8

A total of 45 parts of bisphenol F epoxy resin and 15 parts of novolac resin were melt-mixed, 0.03 part of imidazole accelerator and 30 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. The resin slurry was poured into a hydrothermal kettle filled with distilled water, sealed and cured at 130°C.

Performance test: The viscosity of the epoxy resin slurry prepared in Example 8 at 25° C. was 27.0 mPa.s, the curing time was 6 h, and the compressive strength was 69 MPa.

Example 9

A total of 45 parts of bisphenol F epoxy resin and 40 parts of novolac resin were melt-mixed, 0.03 part of imidazole accelerator and 30 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. The resin slurry was poured into a hydrothermal kettle filled with distilled water, sealed and cured at 130°C.

Performance test: The viscosity of the epoxy resin slurry prepared in Example 9 at 25° C. was 78.0 mPa.s, the curing time was 5 h, and the compressive strength was 71 MPa.

Example 10

A total of 45 parts of bisphenol F epoxy resin and 30 parts of novolac resin were melt-mixed, 0.03 part of imidazole accelerator and 30 parts of acetone were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. The resin slurry was poured into a hydrothermal kettle filled with distilled water, sealed and cured at 130°C.

Performance test: The viscosity of the epoxy resin slurry prepared in Example 10 at 25°C was 40.7 mPa.s, the curing time was 5h, and the compressive strength was 65MPa.

Example 11

A total of 45 parts of bisphenol F epoxy resin and 30 parts of novolac resin were melted and mixed, 0.03 part of imidazole accelerator and 30 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. Pour the resin slurry into a hydrothermal kettle with distilled water, adjust the Ph of the system to 4-5, and cure at 130°C after sealing.

Performance test: The viscosity of the epoxy resin slurry prepared in Example 11 at 25° C. was 48.5 mPa.s, the curing time was 7 h, and the compressive strength was 73 MPa.

Example 12

A total of 45 parts of bisphenol F epoxy resin and 30 parts of novolac resin were melted and mixed, 0.03 part of imidazole accelerator and 30 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. Pour the resin slurry into a hydrothermal kettle with distilled water, adjust the Ph of the system to 5-6, and cure at 130°C after sealing.

Performance test: The measured viscosity of the epoxy resin slurry prepared in Example 12 at 25° C. was 48.5 mPa.s, the curing time was 5 h, and the compressive strength was 88 MPa.

Example 13

A total of 45 parts of bisphenol F epoxy resin and 30 parts of novolac resin were melted and mixed, 0.03 part of imidazole accelerator and 30 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. Pour the resin slurry into a hydrothermal kettle filled with distilled water, adjust the Ph of the system to 6-7, and cure at 130°C after sealing.

Performance test: The viscosity of the epoxy resin slurry prepared in Example 13 at 25° C. was 48.5 mPa.s, the curing time was 5 h, and the compressive strength was 90 MPa.

Example 14

A total of 45 parts of bisphenol F epoxy resin and 30 parts of novolac resin were melted and mixed, 0.03 part of imidazole accelerator and 30 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. Pour the resin slurry into a hydrothermal kettle filled with distilled water, adjust the Ph of the system to 7-8, and cure at 130°C after sealing.

Performance test: The viscosity of the epoxy resin slurry prepared in Example 14 at 25° C. was 48.5 mPa.s, the curing time was 3 h, and the compressive strength was 98 MPa.

Example 15

A total of 45 parts of bisphenol F epoxy resin and 30 parts of novolac resin were melted and mixed, 0.03 part of imidazole accelerator and 30 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. The resin slurry was poured into a hydrothermal kettle filled with saturated magnesium chloride solution, sealed and then cured at 130°C.

Performance test: The viscosity of the epoxy resin slurry prepared in Example 15 at 25° C. was 48.5 mPa.s, the curing time was 6 h, and the compressive strength was 82 MPa.

Example 16

A total of 45 parts of bisphenol F epoxy resin and 30 parts of novolac resin were melted and mixed, 0.03 part of imidazole accelerator and 30 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. The resin slurry was poured into a hydrothermal kettle filled with saturated magnesium sulfate solution, sealed and then cured at 130°C.

Performance test: The measured viscosity of the epoxy resin slurry prepared in Example 16 at 25° C. was 48.5 mPa.s, the curing time was 5 h, and the compressive strength was 83 MPa.

Example 17

A total of 45 parts of bisphenol F epoxy resin and 30 parts of novolac resin were melted and mixed, 0.03 part of imidazole accelerator and 30 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. The resin slurry was poured into a hydrothermal kettle filled with saturated sodium bicarbonate solution, sealed and then cured at 130°C.

Performance test: The viscosity of the epoxy resin slurry prepared in Example 17 at 25° C. was 48.5 mPa.s, the curing time was 3 h, and the compressive strength was 93 MPa.

Example 18

A total of 45 parts of bisphenol F epoxy resin and 30 parts of novolac resin were melted and mixed, 0.03 part of imidazole accelerator and 30 parts of methanol were added, and the mixture was fully stirred. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. The resin slurry was poured into a hydrothermal kettle filled with saturated calcium chloride solution, sealed and cured at 130°C.

Performance test: the viscosity of the epoxy resin slurry prepared in Example 18 at 25° C. was 48.5 mPa.s, the curing time was 6 h, and the compressive strength was 91 MPa.

Example 19

Melt and mix 25 parts of bisphenol F epoxy resin, 27 parts of bisphenol A epoxy resin and 30 parts of novolac resin, add 0.03 part of imidazole accelerator and 30 parts of methanol, and stir well. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. The resin slurry was poured into a hydrothermal kettle filled with distilled water, sealed and cured at 130°C.

Performance test: The measured viscosity of the epoxy resin slurry prepared in Example 19 at 25° C. was 60.8 mPa.s, the curing time was 5 h, and the compressive strength was 97 MPa.

Example 20

Melt and mix 60 parts of bisphenol A epoxy resin and 30 parts of novolac resin, add 0.03 part of imidazole accelerator and 30 parts of methanol, and stir well. To simulate the underground curing environment, a hydrothermal kettle was used as the reaction vessel. The resin slurry was poured into a hydrothermal kettle filled with distilled water, sealed and cured at 130°C.

Performance test: The measured viscosity of the epoxy resin slurry prepared in Example 20 at 25° C. was 105.7 mPa.s, the curing time was 5 h, and the compressive strength was 117 MPa.

Claims (5)

1. The application of the epoxy-phenolic aldehyde system in the water shutoff agent for oil and gas field exploitation is characterized in that the epoxy-phenolic aldehyde system comprises the following raw material components in parts by mass: 45-80 parts of bisphenol F or/and bisphenol A epoxy resin, 10-50 parts of novolac resin, 0.01-0.05 part of imidazole accelerator and 10-60 parts of migratory diluent; the migratable diluent is selected from the group consisting of methanol, ethanol, acetone, butanone, and n-butanol.

2. The use of the epoxy-phenolic aldehyde system in the water shutoff agent for oil and gas field exploitation according to claim 1, wherein when the epoxy resin is a combination of bisphenol F epoxy resin and bisphenol A epoxy resin, the amount of the bisphenol F epoxy resin is not more than 45 parts, and the amount of the bisphenol A epoxy resin is not more than 65 parts.

3. The use of the epoxy-phenolic aldehyde system in the production of water shutoff agents in oil and gas fields as claimed in claim 1 or 2, wherein the epoxy equivalent weight of the bisphenol F and bisphenol A epoxy resin is 150-230 g/mol.

4. Use of the epoxy-phenolic system according to claim 1 or 2 in oil and gas field production water shutoff agents, characterized in that the phenolic resin has a hydroxyl equivalent weight of 90-130 g/mol.

5. The use of the epoxy-phenolic system of claim 3 in oil and gas field production water shutoff agents wherein the phenolic resin has a hydroxyl equivalent weight of 90 to 130 g/mol.

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