Water-dispersible epoxy resin sand consolidant and preparation method thereof

Abstract

The present application relates to the technical field of oil well chemical sand control, and particularly relates to a water-dispersible epoxy resin sand consolidating agent and a preparation method thereof. The water-dispersible epoxy resin with hydrophilic segments and self-emulsifying function is prepared by grafting polyethylene glycol monomethyl ether and phthalic anhydride onto epoxy resin E51 to generate esterification reaction, and the water-dispersible epoxy resin sand consolidating agent is further prepared by compounding the water-dispersible epoxy resin with polyamine curing agent and water, so that the oil field sand consolidating agent with environmental protection and excellent sand consolidation performance is finally obtained. The epoxy resin prepared by the present application has self-emulsifying function, and no additional emulsifier is needed when preparing the emulsion. The sand consolidation effect is excellent, and almost no toxic and harmful volatile gas is generated in the field use, which greatly improves the safety of well site operation, improves the operation environment, significantly reduces the air pollution, ensures the sand consolidation effect, and reduces the complexity and cost of the sand consolidating agent preparation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil well chemical sand control, in particular to a water-dispersible epoxy resin sand consolidant and a preparation method thereof. BACKGROUND

[0002] Many oil reserves in the world are located in poorly cemented reservoirs, so during oil and gas production, sand particles in the reservoir will be washed by fluid and transported to the wellbore, resulting in serious sand production problems. Sand production will have many adverse effects on oil and gas production, causing a lot of economic losses. Therefore, cost-effective and environmentally friendly sand control technology is of great significance in the future development of oil and gas production.

[0003] The main sand control methods for oil and gas wells at present are mechanical sand control and chemical sand control. The mechanical sand control method mainly includes squeeze packing sand control, wellbore screen sand control and cyclic packing sand control. The chemical sand control method is divided into artificial well wall method, bridging sand control method and cementation sand control method according to different sand control mechanisms. The artificial well wall method mainly uses filling materials (such as mortar) to be injected into the formation voids around the wellbore by high-pressure pump, which has a long effective period but a complex process and a small adaptive range. The bridging sand control method is a technology that bridges loose sand particles into stable structures at contact points through chemical agents to prevent sand production, which has a high permeability but a low erosion resistance and a short effective period. The cementation sand control method mainly injects resin-based high molecular materials into loose sand, which has the advantages of simple operation, high consolidation strength and long effective period.

[0004] After the resin-based sand consolidant contacts with sand particles, physical or chemical adsorption will occur due to the presence of a large number of active groups. During the curing process, cross-linking reactions will occur between resin molecules and between resin molecules and curing agents, forming a three-dimensional network of high molecular structure. This overcomes the problems of high cost, complex operation and difficult maintenance of traditional mechanical sand control technology. However, resin-based sand consolidants usually require a large amount of organic solvent as a diluent, which is costly and environmentally unfriendly, restricting its development.

[0005] Patent CN120059700A discloses an epoxy resin-based sand consolidant, which achieves good sand consolidation performance through the use of a combination of a cementing agent and a curing agent system. However, the preparation process of this sand consolidant uses organic solvents such as ethylene glycol monobutyl ether, which produces VOCs upon evaporation, is environmentally unfriendly and poses safety risks. Additionally, the preparation method requires heating and constant temperature treatment of the epoxy resin, as well as 8-12 hours of dissolution of the pH adjuster, resulting in high energy consumption, long process time and limited production efficiency.

[0006] Therefore, there is an urgent need for an environmentally friendly sand consolidant and a preparation method thereof. SUMMARY

[0007] The technical problem to be solved by the present application is to provide a water-dispersible epoxy resin sand consolidant and a preparation method thereof, wherein functional polyethylene glycol monomethyl ether is generated by grafting polyethylene glycol monomethyl ether and phthalic anhydride to epoxy resin E51 to generate an esterification reaction, a water-dispersible epoxy resin with hydrophilic segments and self-emulsifying functions is prepared, a water-dispersible epoxy resin sand consolidant is further prepared by compounding with a polyamine curing agent and water, and finally an oilfield sand consolidant with environmental protection, low cost and excellent sand consolidation performance is obtained.

[0008] A preparation method of a water-dispersible epoxy resin sand consolidant, comprising the following steps:

[0009] (1) polyethylene glycol monomethyl ether and phthalic anhydride are added to a first container, and after being heated and melted, protective gas is introduced, and the polyethylene glycol monomethyl ether and the phthalic anhydride are allowed to react under heating; wherein the mass ratio of the polyethylene glycol monomethyl ether and the phthalic anhydride monomer is 10-15:1;

[0010] (2) epoxy resin E51 and a catalyst are added, and the reaction is continued under heating; wherein the addition amount of the epoxy resin E51 is 75-80wt% of the total mass of the raw materials in the first container; and the addition amount of the catalyst is 0.2-0.4wt% of the total mass of the raw materials in the first container;

[0011] (3) the resin after the reaction in step (2) is taken to another second container with stirring, and deionized water is added dropwise while stirring and heating; the amount of the resin after the reaction is 15-40wt% of the total amount of substances in the second container;

[0012] (4) a curing agent is added to the second container, and stirring and mixing are uniformly performed to obtain a water-dispersible epoxy resin sand consolidant; wherein the addition amount of the curing agent is 10-35wt% of the total amount of substances in the second container.

[0013] Preferably, in step (1), the molecular weight of the polyethylene glycol monomethyl ether is 1900-2100, and as a further preferred molecular weight, it is 2000; and the protective gas is nitrogen.

[0014] Preferably, in step (1), the temperature for heating and melting is 70-80℃, and the heating time is 20-30min.

[0015] Preferably, in step (1), the heating reaction temperature is 90-100℃, and the reaction time is 2-3h.

[0016] Preferably, the mass ratio of the polyethylene glycol monomethyl ether, the phthalic anhydride, the epoxy resin E51 and the catalyst is 18.6:1.4:80:0.22.

[0017] Preferably, in step (2), the catalyst is triphenylphosphine.

[0018] Preferably, in the step (2), the reaction temperature is 110-120℃, and the reaction time is 3h.

[0019] Preferably, in the step (3), mechanical stirring is used, the stirring speed is 800-1000rpm, the heating temperature is 50-60℃, and the speed of dropping deionized water is 3ml / min.

[0020] Preferably, in the step (4), the added curing agent is water-soluble polyamine curing agent DY-175, the stirring speed is 500-600rpm, and the stirring time is 8-10min.

[0021] As further preferred, in the prepared water-dispersible epoxy resin sand consolidant, the mass fraction of the reacted resin in the sand consolidant is 25%, and the mass fraction of the curing agent is 15%.

[0022] The application further provides a water-dispersible epoxy resin sand consolidant prepared by the preparation method of the water-dispersible epoxy resin sand consolidant.

[0023] The oilfield sand consolidant prepared by the preparation method of the application is water-soluble, tightly combined with formation sand after curing, has high consolidation strength and high permeability, can realize high-strength sand consolidation and maintain good permeability of the oil layer, and thus significantly improves the success rate of oil and water well site operation.

[0024] Compared with the prior art, the application has the following beneficial effects:

[0025] (1) The preparation process of the application is simple, environmentally friendly and low in cost, hydrophilic functional polyethylene glycol monomethyl ether is prepared by reacting polyethylene glycol monomethyl ether and phthalic anhydride, and then grafted onto the epoxy resin to prepare a water-soluble sand consolidant. Water is used as the main carrier, the water-based product is non-flammable and non-explosive, the safety level of storage, transportation and use is much higher than that of organic solvent-based products, and the VOC content is extremely low or even zero. This means that it almost does not produce toxic and harmful volatile gases in the field, greatly improves the safety of well site operation, improves the operation environment, and significantly reduces air pollution. The complexity and cost of preparing the sand consolidant are reduced while ensuring the sand consolidation effect.

[0026] (2) The epoxy resin prepared by the application has self-emulsifying function, and no additional emulsifier is needed when preparing the emulsion, which is more environmentally friendly and reduces production cost.

[0027] (3) The sand consolidant of the application has excellent sand consolidation effect. When the resin content in the sand consolidant is 25% and the curing agent content is 15%, the core cementation compressive strength can reach 9.83MPa, and the pure water permeability retention rate can reach 61.1%. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The infrared spectrum (FT-IR) of the water-dispersible epoxy resin sand consolidant of the present application.

[0029] Figure 2 The thermogravimetric (TGA) diagram of the water-dispersible epoxy resin sand consolidant of the present application.

[0030] Figure 3 The particle size distribution diagram of the water-dispersible epoxy resin sand consolidant of the present application.

[0031] Figure 4 The sand consolidation performance test diagram of Test Example 1 of the water-dispersible epoxy resin sand consolidant of the present application.

[0032] Figure 5 The sand consolidation performance test diagram of Test Example 3 of the water-dispersible epoxy resin sand consolidant of the present application. DETAILED DESCRIPTION

[0033] The accompanying drawings are only for illustrative purposes; the technical solutions of the embodiments of the present application will be clearly and completely described in the following. It should be noted that the described examples are only a part of the total embodiments, and are the embodiment of the technical features, objects and effects of the present application. For the process parameters not specifically mentioned, the conventional technology can be referred to.

[0034] Unless specifically mentioned, the reagents used in the present application can be obtained through conventional commercial channels, and the test methods and equipment used are conventional methods and equipment in the technical field.

[0035] Example 1, a preparation method of a water-dispersible epoxy resin sand consolidant, comprising the following steps:

[0036] (1) 18.6 g of polyethylene glycol monomethyl ether and 1.4 g of phthalic anhydride are added to a first container, heated to 80°C, and kept at a constant temperature for 0.5 h, and the two monomers are completely melted;

[0037] Nitrogen is introduced, and the temperature is raised to 100°C for reaction for 3 h;

[0038] (2) 80 g of epoxy resin E51 and 0.22 g of triphenylphosphine are added, and the temperature is raised to 120°C for further reaction for 3 h;

[0039] (3) 25 g of the reacted resin is weighed into another second container with stirring, heated while stirring, and 60 g of deionized water is slowly added dropwise;

[0040] (4) 15 g of a curing agent is added to the second container, stirred and mixed uniformly to obtain a water-dispersible epoxy resin sand consolidant.

[0041] The sand consolidant prepared above is used to prepare a cemented core, and the performance of the sand consolidant is tested, and the preparation method is as follows:

[0042] Preparation of 40-60 mesh quartz sand in a beaker; using ethanol for pretreatment of quartz sand, soak for 30 min, then take out, dry and place in a drying oven; first, the pretreated quartz sand is soaked with water, then mixed with the prepared sand consolidation agent; the mixed sand sample is filled into a φ25mm x 120mm glass tube and compacted, then placed in a 60℃ constant temperature oven for a period of time and then taken out; gently break the glass tube, take out the cemented core, and use a core cutting machine to cut the cemented body into a core sample with a diameter of 25mm and a length of 25mm, and a core sample with a diameter of 25mm and a length of 50mm, for subsequent determination of compressive strength and permeability.

[0043] According to SY / T 5276-2000 "Chemical sand control artificial core compressive strength, bending strength and gas permeability test", the compressive strength of the cemented core is tested.

[0044] According to SY / T 6572-2003 "Sand control resin performance evaluation method", the permeability retention rate of the cemented core is tested.

[0045] The compressive strength of the cemented core of the present embodiment is 9.83 MPa, and the permeability retention rate is 60.1%. The particle size range of the prepared sand consolidation agent is as shown in Figure 3 , and the particle size range is mainly 400-800 nm.

[0046] The water-dispersible epoxy resin prepared in Example 1 was tested by infrared spectroscopy, and the results are shown in Figure 1 . In Figure 1 , a relatively wide absorption peak appears in the range of 3600-3200 cm -1 , which is attributed to the stretching vibration of hydroxyl (-OH); a sharp absorption peak appears in the range of 1750-1720 cm -1 , which is the stretching vibration peak of the carbonyl (C=O) in the ester group; in the range of 1250-1150 cm -1 , a strong stretching vibration absorption peak of C-O-C bond in the ester group is also observed. These characteristic peaks indicate the successful preparation of the water-dispersible epoxy resin.

[0047] The cured product of the water-dispersible epoxy resin sand consolidation agent prepared in Example 1 was tested by thermogravimetry, and the results are shown in Figure 2 . As shown in Figure 2It can be seen that, under the nitrogen atmosphere, the starting point of the modified epoxy resin curing product is 345.7℃, and the ending point is 416.4℃; compared with this, the starting point of the modified epoxy resin curing product is 340.3℃, and the ending point is 425.0℃. The TG curves of the epoxy resin before and after modification are basically coincident, which shows that the chemical modification of the present application greatly improves the water solubility of the epoxy resin, and largely retains the thermal stability of the epoxy resin itself, which guarantees the environmental protection and safety of construction, and also takes into account the mechanical strength and thermal stability of curing in the sand consolidation process.

[0048] Example 2, a preparation method of a water dispersion type epoxy resin sand consolidant, which is different from example 1, wherein 30g of the reacted resin is weighed into another second container with stirring, heated while stirring, and 55g of deionized water is slowly added dropwise.

[0049] The other places not mentioned are the same as example 1.

[0050] According to SY / T 5276-2000 "Chemical sand consolidation artificial core resistance to bending strength, compressive strength and gas permeability test", the compressive strength of the cemented core is tested;

[0051] The experiment shows that the compressive strength of the cemented core of the present embodiment is 11.51MPa, and the permeability retention rate is 45.87%.

[0052] The performance of the water dispersion type epoxy resin sand consolidant prepared by the present application is analyzed.

[0053] Test example 1.

[0054] A preparation method of a water dispersion type epoxy resin sand consolidant, comprising the following steps:

[0055] (1) 18.6g of polyethylene glycol monomethyl ether and 1.4g of phthalic anhydride are added to a first container, heated to 80℃, and kept at a constant temperature for 0.5h, and the two monomers are completely melted;

[0056] Nitrogen is introduced, and the temperature is raised to 100℃ for reaction for 3h;

[0057] (2) 80g of epoxy resin E51 and 0.22g of triphenylphosphine are added, and the temperature is raised to 120℃ for further reaction for 3h;

[0058] (3) 15g, 20g, 25g, 30g, 35g and 40g of the reacted resin are weighed into another second container with stirring, heated while stirring, and deionized water is slowly added dropwise, and the corresponding deionized water is 70g, 65g, 55g, 50g and 45g, respectively;

[0059] (4) Add 15g of curing agent to the second container and stir to mix evenly to obtain water-dispersible epoxy resin sand fixing agent.

[0060] The cemented rock core was prepared using the sand-stabilizing agent obtained above, and its performance was tested. The preparation method is as follows:

[0061] Prepare 40-60 mesh quartz sand in a beaker; pretreat the quartz sand with ethanol, soak for 30 minutes, remove and air dry, then place in a drying oven; first wet the pretreated quartz sand with water, then mix thoroughly with the prepared sand-fixing agent; fill the mixed sand sample into a φ25mm×120mm glass tube and compact it, then place it in a 60℃ constant temperature oven for a period of time before removing it; gently break the glass tube, remove the cemented rock core, and use a core cutter to cut the cemented body into rock core samples with a diameter of 25mm and a length of 25mm and a diameter of 25mm and a length of 50mm, for subsequent determination of compressive strength and permeability.

[0062] The compressive strength of cemented rock cores was tested according to SY / T 5276-2000 "Determination of Flexural Strength, Compressive Strength and Gas Permeability of Chemical Sand Control Artificial Rock Cores";

[0063] The permeability retention rate of cemented rock cores was tested according to SY / T 6572-2003 "Evaluation Method for Performance of Resins for Sand Control".

[0064] The prepared cemented sand cores were tested for compressive strength and permeability retention, and the results are as follows: Figure 4 As shown. By Figure 4 It can be seen that as the resin content in the sand-stabilizing agent increases, the compressive strength of the cemented core continuously rises from 5.19 MPa to 13.53 MPa. This is mainly because resin, as a binder phase, results in tighter bonding between sand grains, stronger overall structure, and improved compressive strength with higher resin content. However, as the resin content increases, the permeability retention rate of the cemented core continuously decreases from 67.47% to 19.83%. This may be because excessive resin fills the pores between sand grains, reducing the channels for fluid permeation and thus lowering the permeability retention rate. There is a negative correlation between compressive strength and permeability retention rate: when the resin content is low, the permeability retention rate is high (fluid easily permeates), but the compressive strength is low (sand body is easily damaged); when the resin content is high, the compressive strength is high (sand body is stable), but the permeability retention rate is low (fluid is difficult to permeate).

[0065] Test Example 2.

[0066] A method for preparing a water-dispersible epoxy resin sand-fixing agent includes the following steps:

[0067] (1) Put 18.6 g of polyethylene glycol monomethyl ether and 1.4 g of phthalic anhydride into a first container, heat to 80°C, and keep the temperature constant for 0.5 h;

[0068] Pass nitrogen, and heat to 100°C for 3 h;

[0069] (2) Add 80 g of epoxy resin E51 and 0.22 g of triphenylphosphine, and continue to heat to 120°C for 3 h;

[0070] (3) Take 25 g of the reacted resin into another second container with stirring, heat while stirring, and slowly add 60 g of deionized water dropwise;

[0071] (4) Add 15 g of a curing agent into the second container, stir to mix uniformly, and obtain a water-dispersed epoxy resin sand consolidant.

[0072] The prepared sand consolidant is used to prepare a cemented core, and the performance of the sand consolidant is tested, and the preparation method is as follows:

[0073] Prepare 40-60 mesh quartz sand in a beaker; use ethanol to pretreat the quartz sand, soak for 30 min, take out, dry, and then place in a drying box; first, immerse the pretreated quartz sand in water, and then mix with the prepared sand consolidant; fill the mixed sand sample into a φ25 mm x 120 mm glass tube and compact, and then place in a constant temperature oven at 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, and 120°C for a period of time and then take out; gently break the glass tube, take out the cemented core, and use a core cutting machine to cut the cemented body into a core sample with a diameter of 25 mm and a length of 25 mm, for use in subsequent determination of compressive strength.

[0074] According to SY / T 5276-2000 "Chemical sand control artificial core determination of compressive strength, compressive strength, and gas permeability", the compressive strength of the cemented core is tested. The experimental results show that the compressive strength of the cemented core of the embodiment is 2.22-9.83 MPa.

[0075] From test example 2, it can be seen that when the curing temperature is 40-60℃, the compressive strength rapidly increases, and the compressive strength is maximum at 60℃, which is 9.83MPa; then with the increase of temperature (70-100℃), the compressive strength presents a slow downward trend, and when the temperature exceeds 90℃, the cemented core begins to appear more brittle fracture; when the temperature reaches 120℃, the compressive strength sharply decreases to 2.22MPa. The reasons are analyzed as follows: when the temperature is low (such as 40℃), the molecular motion is slow, the reaction rate is low, the crosslinking density is insufficient, which leads to weak adhesion between sand particles and low strength; with the increase of temperature (50-60℃), the molecular kinetic energy increases, the collision frequency of epoxy groups and amino groups increases, the crosslinking reaction accelerates, and the three-dimensional network is more dense. And in the water-based system, high temperature promotes water evaporation, reduces the hindrance of water to the reaction (water can dilute the reactants and delay crosslinking), and further promotes the formation of network. The combined action of the two makes the adhesion between sand particles greatly enhanced, and the strength rapidly increases; when the temperature continues to rise (70-100℃), the reaction rate is too fast, the crosslinking density exceeds the "optimal value", the crosslinking network is too rigid, and the internal stress (such as shrinkage stress and thermal stress) is concentrated, which causes microcracks and weakens the adhesion strength. And the water-based polyamine curing agent may aggregate / volatilize at high temperature (amines have low boiling points), which leads to uneven distribution of crosslinking and local weak adhesion; when the temperature reaches 120℃, the molecular chain segments move violently at high temperature, the internal thermal stress of the network increases sharply, which leads to the expansion of macroscopic cracks and the collapse of the sand particle adhesion structure. Moreover, the polyamine curing agent may lose reactivity due to volatilization / oxidation, which cannot supplement crosslinking and accelerate the destruction of the structure. Finally, the adhesion of the sand consolidation system is completely lost, which leads to a sharp decrease in strength.

[0076] Test example 3.

[0077] 10g, 15g, 20g, 25g, 30g, and 35g of curing agent were respectively added into the second container and stirred and mixed uniformly to obtain a water-dispersible epoxy resin sand consolidant.

[0078] The other places not mentioned are the same as in example 1.

[0079] The compressive strength and permeability retention rate of each cemented sand core prepared in test example 3 were tested, and the results are shown in Table 3. Figure 5 Figure 5 ​It can be seen that when the content of the curing agent is 10% to 15%, the compressive strength rapidly increases, and reaches a peak value (9.83 MPa) near 15%; then, with the increase of the content of the curing agent (15% to 35%), the compressive strength continuously decreases; when the content of the curing agent is 10% to 15%, the permeability retention rate rapidly decreases; the decrease slows down when the content of the curing agent is 15% to 25%, and even slightly increases when the content of the curing agent is 25% to 35%. This is mainly because the water-dispersible epoxy resin and the polyamine curing agent are crosslinked by the addition reaction of epoxy groups and amino groups to form a three-dimensional network structure; when the content of the curing agent is low (such as 10%), the crosslinking sites are few, the network structure is sparse, and the adhesion between the sand particles is weak, resulting in low compressive strength. At the same time, the loose network retains more pores, and the fluid is easy to pass through, so the permeability retention rate is high; when the content of the curing agent is moderate (such as 15%), the ratio of the curing agent to the epoxy group is matched, the crosslinking density is high, the network structure is tight, and the sand particles are firmly bonded, so the compressive strength reaches a peak value. The dense structure greatly compresses the pores, and the fluid permeation resistance increases dramatically, resulting in a decrease in the permeability retention rate; when the content of the curing agent is too high (such as 25%), the excessive curing agent leads to a too fast reaction rate, and a "too rigid" network may be formed, the internal stress is concentrated, and even microcracks may occur, resulting in a decrease in the compressive strength, and even brittle fracture. In the water-based system, excessive curing agent may cause phase separation (such as enrichment of amines), destroy the uniformity of the network, and cause local pores to recover, so that the permeability retention rate slightly increases (such as the stage of 25% to 35%).

[0080] It can be seen from test examples 1-3 that the optimal operation temperature of the water-dispersible epoxy resin sand consolidation agent of the application is 60°C, and the optimal mass fraction of the resin after reaction in the sand consolidation agent is 25%, and the optimal mass fraction of the curing agent is 15%.

[0081] Test example 4.

[0082] 25g of the resin after reaction was weighed into another second container with stirring, heated while stirring, and 60g of deionized water was slowly added dropwise;

[0083] 15g of the curing agent was added to the second container, and stirred and mixed uniformly to obtain the water-dispersible epoxy resin sand consolidation agent.

[0084] Respectively, 40-60 mesh, 40-70 mesh, 60-80 mesh, 70-110 mesh, 110-160 mesh, 160-200 mesh quartz sand is placed in a beaker; using ethanol for pretreatment of quartz sand, soak for 30 min, then take out, dry and place in a drying oven; first, the pretreated quartz sand is soaked with water, then mixed with the prepared sand stabilizer; the mixed sand sample is filled into a φ25mm*120mm glass tube and compacted, then placed in a 60℃ constant temperature oven for a period of time and taken out; gently break the glass tube, take out the cemented core, and cut the cemented body into a core sample with a diameter of 25mm and a length of 25mm using a core cutting machine for subsequent determination of compressive strength.

[0085] The compressive strength of the cemented core is tested according to SY / T 5276-2000 "Chemical sand control artificial core compressive strength, compressive strength and gas permeability". The experimental results show that the compressive strength of the cemented core of the present embodiment is 9.8-12.82 MPa.

[0086] As can be seen from Test Example 4, as the particle size of quartz sand gradually decreases, the compressive strength of the cemented core generally shows an upward trend. When the particle size is 40-60 mesh (the largest), the compressive strength is 9.8 MPa; when the particle size is 160-200 mesh (the smallest), the compressive strength is 12.82 MPa, which is significantly improved. The reason is that the smaller the particle size of quartz sand, the larger the specific surface area, and the wider the contact area with the resin, so that the resin can more fully wrap the sand particles and fill the gaps, forming a more dense cemented structure, thereby improving the compressive strength.

[0087] Comparative Example 1, a preparation method of an oil-soluble epoxy resin sand stabilizer, the preparation method is as follows:

[0088] (1) 25g of epoxy resin E51 is added to a container with stirring;

[0089] (2) 60g of acetone is added to the container and mixed evenly;

[0090] (3) 15g of curing agent is added to the container and stirred and mixed evenly to obtain an oil-soluble epoxy resin sand stabilizer.

[0091] The cemented core is prepared using the sand stabilizer prepared above, and the performance of the sand stabilizer is tested, and the preparation method is as follows:

[0092] Preparation of 40-60 mesh quartz sand in a beaker; using ethanol to pretreat the quartz sand, soak for 30 min, then take out, dry and place in a drying oven; first soak the pretreated quartz sand with water, then mix with the prepared sand stabilizer; fill the mixed sand sample into a φ25mm*120mm glass tube and compact, then place in a 60℃ constant temperature oven for a period of time, then take out; gently break the glass tube, take out the cemented core, and use a core cutting machine to cut the cemented body into a core sample with a diameter of 25mm and a length of 25mm, and a core sample with a diameter of 25mm and a length of 50mm, for subsequent determination of compressive strength and permeability.

[0093] According to SY / T 5276-2000 "Chemical sand control artificial core compressive strength, compressive strength and gas permeability test", the compressive strength of the cemented core is tested.

[0094] According to SY / T 6572-2003 "Resin performance evaluation method for sand control", the permeability retention rate of the cemented core is tested.

[0095] The experimental results show that the compressive strength of the cemented core of the present embodiment is 5.06MPa, and the permeability retention rate is 51.82%.

[0096] According to the performance test of the sand stabilizer prepared by example 1 and comparative example 1, the sand stabilizer after chemical modification significantly improves the water solubility of epoxy resin, significantly improves the compressive strength of the cemented core, and the compressive strength is increased by 94.3%, and the permeability is increased by 17.9%.

[0097] Of course, the above description is not a limitation of the present application, and the present application is not limited to the above examples, and the changes, modifications, additions or replacements made by the skilled in the art within the essential scope of the present application should also belong to the protection scope of the present application.

Claims

1. A method for preparing a water-dispersible epoxy resin sand-fixing agent, characterized in that, Includes the following steps: (1) Polyethylene glycol monomethyl ether and phthalic anhydride are added to the first container, heated and melted, and then a protective gas is introduced to allow the polyethylene glycol monomethyl ether and phthalic anhydride to react under heating; wherein the mass ratio of polyethylene glycol monomethyl ether to phthalic anhydride monomers is 10-15:1; wherein the heating and melting temperature is 70-80℃ and the heating time is 20-30 min; the heating and reaction temperature is 90-100℃ and the reaction time is 2-3 h; (2) Add epoxy resin E51 and catalyst, and continue heating the reaction; wherein the amount of epoxy resin E51 added is 75-80 wt% of the total mass of the raw materials in the first container; the amount of catalyst added is 0.2-0.4 wt% of the total mass of the raw materials in the first container; (3) Take the resin from step (2) after the reaction is complete and put it into a second container with a stirrer. Stir and heat the container while adding deionized water dropwise. Take the amount of resin after the reaction is complete, which is 15-40 wt% of the total amount of substances in the second container. (4) Add the curing agent to the second container and stir to mix evenly to obtain a water-dispersible epoxy resin sand-fixing agent; wherein, the amount of curing agent added is 10-35 wt% of the total amount of material in the second container; The mass ratio of polyethylene glycol monomethyl ether, phthalic anhydride, epoxy resin E51, and catalyst is 18.6:1.4:80:0.22; the catalyst is triphenylphosphine; and the added curing agent is water-soluble polyamine curing agent DY-175.

2. The method for preparing a water-dispersible epoxy resin sand-fixing agent according to claim 1, characterized in that, In step (1), the molecular weight of polyethylene glycol monomethyl ether is 1900-2100; the protective gas is nitrogen.

3. The method for preparing a water-dispersible epoxy resin sand-fixing agent according to claim 1, characterized in that, In step (2), the reaction temperature is 110-120℃ and the reaction time is 3h.

4. The method for preparing a water-dispersible epoxy resin sand-fixing agent according to claim 1, characterized in that, In step (3), mechanical stirring is used at a speed of 800-1000 rpm; the heating temperature is 50-60℃; and the rate of adding deionized water is 3 ml / min.

5. The method for preparing a water-dispersible epoxy resin sand-fixing agent according to claim 1, characterized in that, In step (4), the stirring speed is 500-600 rpm and the stirring time is 8-10 min.

6. The water-dispersible epoxy resin sand-fixing agent prepared by the method for preparing a water-dispersible epoxy resin sand-fixing agent according to any one of claims 1-5.

Images