Temperature response type resin plugging agent as well as preparation method and application thereof

Abstract

The invention discloses a temperature response type resin plugging agent as well as a preparation method and application thereof, and belongs to the field of oilfield chemistry. The temperature response type resin plugging agent comprises temperature response type resin particles, a dispersion stabilizer and water, and the dispersion stabilizer is a C7025 polymer. Different from a traditional chemical plugging agent needing to be injected with a catalyst or a cross-linking agent, gel forming of the resin plugging agent is triggered by the formation temperature, the catalyst or the cross-linking agent does not need to be added subsequently, the construction technology is simplified, and errors and complexity of medicine adding are reduced. By adjusting the formula of the resin profile control agent system, the gelling temperature and the gelling time can be adjusted, it is ensured that the resin profile control agent keeps flowing before reaching a target zone and is rapidly gelling after reaching the target zone, and the risk of premature solidification near a shaft is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil field chemistry, in particular to a temperature-responsive resin plugging agent, a preparation method and application thereof. BACKGROUND

[0002] With the continuous growth of global energy demand and the increasing depletion of conventional oil and gas resources, oilfield development gradually extends to complex geological conditions (such as high water cut, low permeability, fractured reservoirs) and secondary development of old oilfields. However, in the process of oilfield development, problems such as formation heterogeneity, high permeability layer water channeling, and fracture reservoir channeling seriously restrict the improvement of oil recovery. According to statistics, the average recovery rate of global oilfields is only about 35%, and a large amount of remaining oil is stranded underground due to uneven displacement or ineffective circulation. Especially in the high water cut development stage, the water cut of oil wells is generally more than 80%, leading to a sharp increase in production cost and a decline in economic benefit. Under this background, how to effectively control the flow path of injected fluid, plug invalid water channeling channels, and improve displacement efficiency has become a core problem to be solved in oilfield development.

[0003] Traditional water control and oil stabilization technologies (such as mechanical isolation, polymer gel profile control, and particle plugging) have alleviated the problem of water channeling to some extent, but their limitations have become increasingly apparent. For example, polymer gels have poor temperature resistance and salt tolerance and are prone to degradation and failure in high-temperature and high-salt reservoirs; particle plugging agents tend to accumulate near the wellbore and are difficult to penetrate deep into the formation; and mechanical isolation can only solve the local problem near the wellbore and lacks long-term plugging ability for complex fracture networks or large channels. Therefore, developing a chemical plugging material with high strength, long-term stability, and wide adaptability has become a key breakthrough for upgrading oilfield development technology.

[0004] As a new type of chemical water plugging material, resin plugging agent has gradually become an important technical means to solve the water control problem in complex reservoirs due to its unique physical and chemical properties. Compared with traditional plugging agents, resin plugging agents have the following advantages: (1) Strength and long-term effectiveness: Resin forms a three-dimensional network structure through cross-linking and solidification, with a compressive strength of more than 10 MPa, much higher than that of polymer gels (usually <1 MPa), and is insoluble in water after solidification, with excellent resistance to erosion and a plugging effective period of up to several years.

[0005] (2) Temperature resistance and salt tolerance adaptability: Some resin systems (such as phenolic resin and modified furan resin) can work stably in high-temperature environments above 180℃ and high-salinity conditions with a salinity of more than 20×10 4 g / L, suitable for deep sea, deep layer, and high-salinity reservoirs.

[0006] (3) Precise plugging ability: Liquid resin prepolymer preferentially enters high permeability layers or fractures, achieving selective plugging through in-situ curing, reducing damage to low permeability reservoirs, and being particularly suitable for oil reservoirs with severe heterogeneity.

[0007] (4) Multifunctional composite potential: The resin system can form a high-performance composite system by introducing nanomaterials (such as silicon dioxide and clay), intelligent response polymers or environmentally friendly modifiers, expanding its application scenarios in the development of unconventional resources such as tight oil and shale gas.

[0008] These technical characteristics make resin plugging agents have great potential in water plugging and profile control, fracture plugging, old well repair, etc. For example, in the application of a certain high-water-cut oilfield in Bohai Bay, the phenolic resin plugging agent successfully reduced the water cut of the oil well from 92% to 68%, and increased the daily oil production by 4 times. The technical feasibility of the plugging agent also provides economic support for its large-scale promotion.

[0009] Since the 1980s, the research on resin plugging agents has undergone iterative upgrading from single resin systems to composite functional materials. Early research mainly focused on the synthesis and curing mechanism optimization of phenolic resin and epoxy resin, aiming to improve their temperature resistance and curing strength. In the 21st century, with the rise of nanotechnology and green chemistry concepts, the research direction gradually shifted to the development of environmentally friendly resins (such as bio-based furan resin), intelligent response resins (such as temperature / pH sensitive resins) and nanocomposite resins. For example, the nanomodified epoxy resin system developed by Halliburton can remain stable at 200℃ and significantly improve the efficiency of fracture filling; the lignin-phenolic composite resin developed by China University of Petroleum reduces environmental toxicity by replacing part of the phenol with biomass. However, the widespread application of resin plugging agents still faces challenges such as cost and environmental pressure, adaptability to complex reservoirs, and complexity of construction process. SUMMARY

[0010] The purpose of the present application is to provide a temperature-responsive resin plugging agent, its preparation method and application. The temperature-responsive resin plugging agent of the present application forms a gel through secondary cross-linking by chemical bonds underground, and the formation temperature of the gel is in the range of 50-100℃. The initial low viscosity of the gel ensures good injectivity and deep migration ability. At the same time, the gel forms a high-strength and stable gel through cross-linking by chemical bonds underground, effectively plugging high permeability channels, and greatly improving the oil recovery rate.

[0011] The present application first provides a temperature-responsive resin plugging agent, which comprises temperature-responsive resin particles, a dispersion stabilizer and water.

[0012] In the above-mentioned temperature-responsive resin plugging agent, the dispersion stabilizer is C7025 polymer.

[0013] The temperature-responsive resin particle has a mass percentage concentration of 0.5%-3% in the temperature-responsive resin profile control agent. The mass percentage concentration of the dispersion stabilizer is 0.05%-0.3%; preferably 0.1%.

[0014] The raw materials for preparing the temperature-responsive resin particle in the temperature-responsive resin profile control agent include the following: an epoxy resin, a curing agent 1, a catalyst, a curing agent 2, and a density regulator. The epoxy resin is epoxy resin E51 and / or epoxy resin E44. The curing agent 1 is 3.3'-thiodipropionic acid. The catalyst is at least one of zinc acetate, zinc acetylacetone, and triethanolamine. The curing agent 2 is at least one of polyethylene glycol, succinic anhydride, and methylhexahydrophthalic anhydride. The density regulator is a silica particle and / or a glass microsphere.

[0015] The ratio of the sum of the moles of the curing agent 1 and the curing agent 2 to the moles of the epoxy resin is 0.5-1:1; specifically, 1:1. The mole percentage of the curing agent 1, based on the total moles of the curing agent 1 and the curing agent 2, is 30%-50%; specifically, 30%. The moles of the catalyst are 10%-30% of the moles of the epoxy resin; specifically, 20%. The mass of the density regulator is 10%-20% of the mass of the epoxy resin; specifically, 10%.

[0016] The preparation method of the temperature-responsive resin particle in the temperature-responsive resin profile control agent includes the following: The epoxy resin is heated, and then the curing agent 1, the catalyst, the curing agent 2, and the density regulator are added, and the system is high-temperature cured, crushed, and sieved to obtain the temperature-responsive resin particle.

[0017] Specifically, the preparation method of the temperature-responsive resin particle includes the following: The epoxy resin is heated, and then the curing agent 1 is added and stirred, followed by the addition of the catalyst and stirring, then the addition of the curing agent 2 and stirring, and finally the addition of the density regulator; the above system is high-temperature cured, crushed, and sieved to obtain the temperature-responsive resin particle.

[0018] The heating temperature in the temperature-responsive resin profile control agent is 60-100℃; specifically, 80℃. The high-temperature curing conditions are as follows: 110-120 DEG C for 1-3h, then 130-140 DEG C for 1-3h, and finally 150-160 DEG C for 1-3h; specifically, 120 DEG C for 2h, then 140 DEG C for 2h, and finally 160 DEG C for 2h.

[0019] In the temperature-responsive resin particle preparation method, the broken particles are sieved to 400-500 mesh by a sieve.

[0020] The application further provides a preparation method of the temperature-responsive resin profile control agent, comprising the following steps: mixing the temperature-responsive resin particles, the dispersion stabilizer and water to obtain the temperature-responsive resin profile control agent.

[0021] Finally, the application provides application of the temperature-responsive resin profile control agent in oil and gas reservoir enhanced recovery.

[0022] In the application, the formation temperature of the oil and gas reservoir is 50-100 DEG C; specifically, 65 DEG C.

[0023] The formation salinity of the oil and gas reservoir is 6000-8000 mg / L.

[0024] In the application, the temperature-responsive resin profile control agent is used as a water plugging and profile control agent to improve the recovery of crude oil and / or natural gas.

[0025] The application has the following advantages: (1) Unlike conventional chemical plugging agents that need to inject a catalyst or a crosslinking agent, the resin profile control agent of the application is triggered by the formation temperature to form a gel, without the need for subsequent addition of a catalyst or a crosslinking agent, thereby simplifying the construction process and reducing the error and complexity of drug addition.

[0026] (2) By adjusting the formula of the resin profile control agent system, the gelation temperature and gelation time thereof can be adjusted to ensure that it remains flowable before reaching the target zone and quickly forms a gel after reaching the target zone, thereby avoiding the risk of premature solidification near the wellbore.

[0027] (3) The resin profile control agent of the application has excellent chemical stability, resistance to formation water salinity, resistance to degradation, and good long-term stability, and is not prone to dehydration shrinkage or degradation, so the plugging effect is durable.

[0028] (4) Compared with heavy metal crosslinked polymer gels such as chromium salts, the resin profile control agent of the application has less potential harm to the environment. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a preparation flowchart of the temperature-sensitive resin profile control agent.

[0030] Figure 2 The dispersion stability of temperature-responsive resin blocking agent configured under different dispersion stabilizers (the storage temperature is 25℃); wherein the left graph is the initial state, and the right graph is the state after being stored for 2 days.

[0031] Figure 3 The viscosity of temperature-responsive resin blocking agent with different concentrations.

[0032] Figure 4 The viscoelasticity of temperature-responsive resin blocking agent with different concentrations.

[0033] Figure 5 The gelation condition of temperature-responsive resin blocking agent placed at the target reservoir temperature; wherein, Figure 5 a is the normal temperature state; b is the state just warmed to 65℃; and c is the state after being stored at 65℃ for 3 days.

[0034] Figure 6 The viscosity curve of temperature-responsive resin blocking agent after being stored at the target reservoir temperature for 3 days.

[0035] Figure 7 The core plugging experiment device diagram; wherein 1 is a kerosene tank; 2 is a horizontal flow pump; 3 is a simulated water tank; 4 is a chemical agent stirring tank; 5 is a core holder; 6 is a pressure sensor; 7 is a measuring cylinder; 8 is a hand pump; and 9 is a computer.

[0036] Figure 8 The homogeneous core plugging curve diagram.

[0037] Figure 9 The heterogeneous core plugging curve diagram. DETAILED DESCRIPTION

[0038] The application will be further described in detail below with specific embodiments, and the given examples are only for illustrating the application, but not for limiting the scope of the application.

[0039] The experimental methods in the following examples are all conventional methods, unless otherwise specified.

[0040] The quantitative tests in the following examples are all set with three repeated experiments, and the results are averaged, unless otherwise specified.

[0041] The materials and reagents used in the following examples can be obtained from commercial channels, unless otherwise specified.

[0042] The experimental materials and reagents used in the following examples are as follows: Basic materials: epoxy resin E51, E44, purchased from Nantong Xingchen Synthetic Material Co., Ltd.; Curing agent 1: 3.3'-thiodipropionic acid (98%), purchased from Shanghai Maikelin Biochemical Technology Co., Ltd.; Catalyst: zinc acetate, zinc acetylacetonate, triethanolamine (98%) were purchased from Shanghai Melin Biological Technology Co., Ltd. Curing agent 2: polyethylene glycol 400, succinic anhydride, methyl hexahydrophthalic anhydride were purchased from Jinan Qingtian Chemical Technology Co., Ltd. Density regulator: silica particles, glass microspheres were purchased from 3M Minnesota Mining and Manufacturing Company; Dispersing stabilizer: C7025 polymer was purchased from Aisen (China) Flocculant Co., Ltd.; OBS-50 (sodium heavy alkyl benzene sulfonate), AES (sodium fatty alcohol polyoxyethylene ether sulfate), SDS (sodium dodecyl sulfate), APE-4P surfactant (polyoxyethylene nonyl phenol phosphate) were purchased from Shandong Yousuo Chemical Technology Co., Ltd. Inorganic salt (used for preparing mineralized water): sodium carbonate (Na2CO3, 99.99%), sodium chloride (NaCl, 99.99%), sodium sulfate (Na2SO4, 99.99%), sodium bicarbonate (NaHCO3, 99.99%), calcium chloride (CaCl2, 99.99%), magnesium chloride hexahydrate (MgCl2·6H2O, 99.99%), potassium chloride (KCl, 99.99%), etc. were purchased from Shanghai Melin Biological Technology Co., Ltd. Others: kerosene was purchased from Beijing Shidahuading Technology Co., Ltd.; deionized water and cores used for plugging experiments were prepared in the laboratory.

[0043] Example 1, preparation of temperature-responsive resin plugging agent (1) First, 100 g (0.26 mol) of epoxy resin E51 or E44 was poured into a beaker and heated to 80°C in a water bath. Then 30% of the molar amount of the epoxy resin was added to the curing agent 1 and heated and stirred for 20 min. Then 20% of the molar amount of the epoxy resin was added to the catalyst (zinc acetate, zinc acetylacetonate or triethanolamine), and stirred for 1 min. Then the total molar amount of curing agent 1 and curing agent 2 was added to the epoxy resin, and the solution changed from white turbidity to transparent. After stirring evenly, 10% (based on the mass of the epoxy resin) of the density regulator (silica particles or glass microspheres) was added. Then it was placed in an oven for high-temperature curing, and the curing system was 120°C-2h, 140°C-2h, 160°C-2h. After curing, it was broken and sieved to about 400-500 mesh, and temperature-responsive resin particles were obtained.

[0044] (2) According to the actual conditions of the target reservoir, the corresponding proportion of inorganic salt drugs is configured into formation simulation water, and 0.1% of the dispersion stabilizer (C7025 polymer, OBS-50, AES, SDS or APE-4P) is added to improve the dispersion stability of the resin blocking agent solution. The temperature-responsive resin particles are configured into a temperature-sensitive resin blocking agent (preparation process as shown in Figure 1 ) at a mass percentage concentration of 0.5%-3%. The basic performance evaluation experiment and the plugging performance evaluation experiment are carried out at the temperature of the target reservoir.

[0045] The evaluation tests of the following examples 2 and 3 and the raw materials of the temperature-responsive resin particles used are as follows: epoxy resin E51, curing agent 1 3.3'-thiodipropionic acid, catalyst triethanolamine, curing agent 2 polyethylene glycol 400, density regulator silicon dioxide particles. Other preparation methods and conditions are the same as described above.

[0046] Example 2, temperature-responsive resin blocking agent basic performance evaluation test (1) Temperature-responsive resin blocking agent dispersion stability test Under laboratory conditions, according to the analysis results of the target oil group formation water, sodium carbonate, sodium chloride, sodium sulfate, sodium bicarbonate, calcium chloride, magnesium chloride hexahydrate and potassium chloride and other inorganic salt drugs are selected to configure the formation simulation water with a salinity of 8000mg / L; the temperature-responsive resin particles and different dispersion stabilizers (mass percentage concentration in the system is 0.1%) are selected to configure the temperature-sensitive resin blocking agent with a mass percentage concentration of 2% using the above formation simulation water, and the dispersion stability of the temperature-responsive resin particles is tested (see Figure 2 ).

[0047] As can be seen from Figure 2 , when the polymer C7025 is used as a dispersion stabilizer, the dispersion performance of the temperature-sensitive resin blocking agent is the best, and the rheological properties of the temperature-sensitive resin blocking agent are tested subsequently using the polymer C7025 as a dispersion stabilizer.

[0048] (2) Rheological property test of temperature-sensitive resin blocking agent Using polymer C7025 as a dispersion stabilizer (mass percentage concentration in the system is 0.1%), using formation simulation water with a salinity of 8000mg / L, the resin particles are configured into temperature-sensitive resin blocking agent at a mass percentage concentration of 0.5%, 1%, 2% and 3%, and the viscosity (test temperature is 25℃) and viscoelastic properties (test temperature is 25℃) are tested according to the rotary method in GB / T 10247-2008 standard.

[0049] The viscosity of the temperature-sensitive resin blocking agent with different concentrations is shown in Figure 3 , and Figure 3It can be seen that the initial viscosity of the temperature-sensitive resin blockage regulator system with different concentrations is relatively low. The viscoelasticity of the temperature-sensitive resin blockage regulator with different concentrations is shown in [the table / reference needed]. Figure 4 ,Depend on Figure 4 It can be seen that at low frequency shear (<1Hz), both the elastic modulus and the viscous modulus are less than 5 Pa, and the low flow resistance makes it have good injectability in the reservoir.

[0050] (3) Test of gelation of temperature-sensitive resin blockage regulator The gelation temperature range of temperature-responsive resin particles can be adjusted from 50-100℃ by adjusting the amount of curing agent added.

[0051] The thermosensitive resin plugging agent (0.1% C7025 as dispersant and stabilizer, and 2% by mass of temperature-responsive resin particles) was placed at the target reservoir temperature (65℃) to observe its gelation behavior and test the gelation effect. Results are shown below. Figure 5 ,Depend on Figure 5 It is known that the particles in the temperature-sensitive resin plugging agent gradually cross-link until they form a gel at the formation response temperature.

[0052] Figure 6 This study aims to obtain the viscosity curve (test temperature: 65℃) of a temperature-sensitive resin plugging agent (0.1% C7025 as a dispersant and stabilizer, and 2% by mass of temperature-responsive resin particles) after 3 days at the target reservoir temperature. The results show that the viscosity of the temperature-sensitive resin plugging agent increases rapidly after gelation at the target reservoir temperature for 3 days, demonstrating its effective ability to plug high-permeability layers. Subsequent core plugging experiments will be conducted to evaluate its plugging performance.

[0053] Example 3: Evaluation and Testing of the Plugging Performance of Temperature-Responsive Resin Plugging Agent A temperature-sensitive resin plugging agent with a mass percentage concentration of 2% (0.1% C7025 as a dispersant and stabilizer) was selected, with a penetration rate of 1×10⁻⁶. 4 Homogeneous and heterogeneous cores with a diameter of approximately mD were heated to gel at the target reservoir temperature (65℃) and their core sealing effect was tested to evaluate their sealing performance.

[0054] (1) Core permeability measurement Connect the experimental apparatus according to the schematic diagram of the core plugging experiment. (See diagram of the core plugging experimental apparatus.) Figure 7After the air tightness of the experimental device is verified by testing, the experiment can be carried out. The core saturated with formation simulation water is placed in the core holder, a stable confining pressure of 8 MPa is applied, and it is ensured that the confining pressure is stable and there is no water leakage in the device. Subsequently, the injection pump is opened, and the pre-prepared formation simulation water (salinity 8000 mg / L) is injected at a flow rate of 1.3 mL / min, while the pressure data are read and collected using a pressure sensing device. After the water injection pressure is stable, the front-end detection pressure at this time is read, and the water permeability of the core is calculated according to Darcy's formula.

[0055] (2) Plugging experiment The liquid required for the experiment is filled in each tank, and the pipelines connected with each tank are filled with the same liquid. The confining pressure of the core holder is stabilized at 8 MPa, and the injection speed of the horizontal flow pump is set to 1.3 mL / min. When the pressure is stable, the pressure value P1 is recorded. Then, 2% of the temperature-sensitive resin plugging agent is transferred into the core, and when the injection amount reaches 1 PV, the pressure value P2 is recorded. The formation simulation water is injected again until the pressure is stable again, and the pressure value P3 is recorded. The permeability at this time is calculated according to Darcy's formula, the plugging rate is calculated, and the plugging effect is compared.

[0056] Table 1 Plugging experiment results of the plugging agent

[0057] The plugging curve diagram of the homogeneous core is shown in Figure 8 , and the plugging curve diagram of the heterogeneous core is shown in Figure 9 .

[0058] From Figures 8-9 and Table 1, it can be seen that the temperature-sensitive resin plugging agent of the present application has a low initial injection viscosity, and after being injected into the core, it is cross-linked into a gel through chemical bonds at the formation temperature. Through the core plugging performance experiment, it is known that the plugging rate of the homogeneous core can reach more than 95%; for the heterogeneous core, the plugging effect of the high permeability reservoir is good, the secondary water injection water flows along the dominant channel, the pressure is greatly reduced, and the plugging rate can reach more than 90%.

Claims

1. A temperature-responsive resin blockage regulator, comprising temperature-responsive resin particles, a dispersant stabilizer, and water.

2. The temperature-responsive resin blockage regulator according to claim 1, characterized in that: The dispersion stabilizer is a C7025 polymer.

3. The temperature-responsive resin blockage regulator according to claim 1 or 2, characterized in that: In the temperature-responsive resin blockage accelerator, the mass percentage concentration of the temperature-responsive resin particles is 0.5%-3%; The mass percentage concentration of the dispersant stabilizer is 0.05%-0.3%; preferably 0.1%.

4. The temperature-responsive resin blockage modifier according to any one of claims 1-3, characterized in that: The raw materials for preparing the temperature-responsive resin particles include the following: epoxy resin, curing agent 1, catalyst, curing agent 2, and density regulator; The epoxy resin is epoxy resin E51 and / or epoxy resin E44; The curing agent 1 is 3,3'-thiodipropionic acid; The catalyst is at least one of zinc acetate, zinc acetylacetonate, and triethanolamine; The curing agent 2 is at least one of polyethylene glycol, succinic anhydride and methylhexahydrophthalic anhydride; The density regulator is silica particles and / or glass microspheres.

5. The temperature-responsive resin blockage regulator according to claim 4, characterized in that: The ratio of the sum of the molar numbers of curing agent 1 and curing agent 2 to the molar number of epoxy resin is 0.5-1:1; specifically, it can be 1:

1. Based on the total molar number of curing agent 1 and curing agent 2, the molar percentage of curing agent 1 is 30%-50%; The molar amount of the catalyst is 10%-30% of the molar amount of the epoxy resin; The density regulator is 10%-20% of the mass of the epoxy resin.

6. The temperature-responsive resin blockage regulator according to claim 4 or 5, characterized in that: The method for preparing the temperature-responsive resin particles includes the following: The epoxy resin is heated, and then curing agent 1, catalyst, curing agent 2 and density regulator are added. The resin is then cured at high temperature and crushed to obtain the temperature-responsive resin particles.

7. The temperature-responsive resin blockage regulator according to claim 6, characterized in that: The heating temperature is 60-100℃; The conditions for high-temperature curing are as follows: keep at 110-120℃ for 1-3 hours, then keep at 130-140℃ for 1-3 hours, and finally keep at 150-160℃ for 1-3 hours.

8. A method for preparing the temperature-responsive resin blockage regulator according to any one of claims 1-7, comprising the following steps: mixing the temperature-responsive resin particles, a dispersant stabilizer and water to obtain the temperature-responsive resin blockage regulator.

9. The application of the temperature-responsive resin plugging agent according to any one of claims 1-7 in enhancing oil and gas reservoir recovery.

10. In the application according to claim 9, the formation temperature of the oil and gas reservoir is 50-100℃.

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