High temperature resistant interpenetrating network enhanced plugging agent composition, plugging agent and preparation method and application thereof

Abstract

The application relates to the technical field of oil exploitation, and discloses a high-temperature-resistant interpenetrating network type reinforced plugging agent composition, a plugging agent and a preparation method and application thereof. The composition contains a composite material, a crosslinking agent, inorganic particles and water; the content of the composite material is 0.8-1.5 parts by weight, the content of the crosslinking agent is 1.0-20 parts by weight, and the content of the inorganic particles is 2-8 parts by weight, relative to 100 parts by weight of water. The high-temperature-resistant interpenetrating network type reinforced plugging agent prepared by the application has a more compact gel network structure, has the advantages of high strength and good stability, and also has excellent temperature resistance.

Description

Technical Field

[0001] This invention relates to the field of oil extraction technology, specifically to compositions for high-temperature resistant interpenetrating network-type reinforced plugging agents, plugging agents, their preparation methods, and applications. Background Technology

[0002] With the continuous development of water injection and gas displacement in fractured-vuggy carbonate reservoirs, the reservoirs have entered a high water-cut stage. Fractured-vuggy carbonate reservoirs, influenced by karst processes, form karst-characteristic reservoir environments. The reservoirs exhibit strong heterogeneity and diverse reservoir space types. The reservoir structure is mainly based on the complex and disordered interweaving of dissolution pores, large caverns, and fractures. Caverns are the primary oil and gas storage spaces, while fractures and pores are the main channels. Furthermore, the reservoirs are buried at depths exceeding 6000m, with formation temperatures ranging from 130-150℃ and formation water salinity around 200,000-220,000. Therefore, the harsh reservoir environment places higher demands on the strength and temperature resistance of water shut-off and profile control agents.

[0003] Inorganic plugging agents lack water-stopping selectivity and tend to block both oil and water channels, thus blocking oil as well as water. Therefore, in recent years, colloidal plugging agents have been the primary type used for water shut-off and profile modification in fractured-vuggy reservoirs. However, the strength of colloidal plugging agents is only suitable for small fractures of millimeters or 1-3 cm in size. For large-scale fractures and water-channeling fractures, the strength of colloidal plugging agents is insufficient, and their temperature resistance is limited, resulting in an overall water shut-off effectiveness of approximately 90 days. Improving the strength and effectiveness of colloidal plugging agents is currently key to improving the water shut-off effect in fractured-vuggy reservoirs. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing colloidal plugging agents, such as insufficient strength and short effective period of water plugging.

[0005] To achieve the above objectives, a first aspect of the present invention provides a composition for a high-temperature resistant interpenetrating network type reinforced plugging agent, the composition comprising a composite material, a crosslinking agent, inorganic particles and water;

[0006] The content of the composite material relative to 100 parts by weight is 0.8-1.5 parts by weight, the content of the crosslinking agent is 1.0-20 parts by weight, and the content of the inorganic particles is 2-8 parts by weight.

[0007] The composite material is an acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer and N-vinylpyrrolidone in a mass ratio of 1-2:1;

[0008] The weight-average molecular weight of the acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer is 6 million to 7.5 million.

[0009] The inorganic particles are modified nano-silica and modified mineral powder in a mass ratio of 1:2-5.

[0010] A second aspect of the present invention provides a method for preparing a high-temperature resistant interpenetrating network type reinforced plugging agent, the method being carried out using the components of the composition described in the first aspect, comprising:

[0011] (1) The composite material is brought into contact with water for the first time to obtain mixture I;

[0012] (2) The mixture I is brought into a second contact with a crosslinking agent to obtain mixture II;

[0013] (3) The mixture II is subjected to a third contact and aging with inorganic particles in sequence to obtain the high-temperature resistant interpenetrating network type reinforced plugging agent.

[0014] A third aspect of the present invention provides a high-temperature resistant interpenetrating network type reinforced plugging agent prepared by the method described in the second aspect.

[0015] A fourth aspect of the present invention provides the application of the high-temperature resistant interpenetrating network type reinforced plugging agent described in the third aspect in the development of fractured-vuggy reservoirs.

[0016] Compared with the prior art, the present invention has at least the following advantages through the above technical solution:

[0017] (1) The high-temperature resistant interpenetrating network type reinforced plugging agent provided by the present invention has a dense gel network structure, higher strength, and better stability.

[0018] (2) The high-temperature resistant interpenetrating network type reinforced plugging agent provided by the present invention has a high storage modulus (or elastic modulus) and strong resistance to deformation; at the same time, the plugging agent has a large loss modulus (or viscous modulus), strong adhesion of the colloid, and strong resistance to erosion. Attached Figure Description

[0019] Figure 1 Infrared spectrum of modified nano-silica;

[0020] Figure 2 Scanning electron microscope image of a high-temperature resistant interpenetrating network-type reinforced plugging agent;

[0021] Figure 3 The image shows the viscoelastic modulus strength test results for a high-temperature resistant interpenetrating network type reinforced plugging agent. Detailed Implementation

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] As previously stated, a first aspect of the present invention provides a composition for a high-temperature resistant interpenetrating network type reinforced plugging agent, the composition comprising a composite material, a crosslinking agent, inorganic particles and water;

[0024] The content of the composite material relative to 100 parts by weight is 0.8-1.5 parts by weight, the content of the crosslinking agent is 1.0-20 parts by weight, and the content of the inorganic particles is 2-8 parts by weight.

[0025] The composite material is an acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer and N-vinylpyrrolidone (NVP) in a mass ratio of 1-2:1.

[0026] The weight-average molecular weight of the acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer is 6 million to 7.5 million.

[0027] The inorganic particles are modified nano-silica and modified mineral powder in a mass ratio of 1:2-5.

[0028] According to a preferred embodiment, the content of the composite material is 1.2-1.3 parts by weight relative to 100 parts by weight of water, the content of the crosslinking agent is 1.2-15 parts by weight, and the content of the inorganic particles is 4-6 parts by weight. In this preferred embodiment, the high-temperature resistant interpenetrating network reinforced plugging agent provided by the present invention has high storage modulus and loss modulus, and its high-temperature stability is extended to more than 200 days compared with ordinary colloidal plugging agents.

[0029] According to a preferred embodiment, the modified nano-silica is obtained by reacting a surface modifier I with nano-silica at a mass ratio of 0.01-0.1:1. In this preferred embodiment, the high-temperature resistant interpenetrating network reinforced plugging agent provided by the present invention has the following properties: it can withstand high temperatures of 150°C, and its colloidal strength reaches the rigidity of a Class I colloid (the visual strength of the colloid is judged from Class AI). Its storage modulus strength can reach 332.2 Pa, and although the frequency increases to 10Hz, the storage modulus G'>>G'', indicating that the high-temperature resistant interpenetrating network reinforced plugging agent can maintain its strength under more severe conditions (long-term static storage, high temperature), that is, it has high strength and good stability.

[0030] According to a preferred embodiment, the surface modifier I is selected from at least one of γ-glycidoxypropyltrimethoxysilane, aminopropyltriethoxysilane, sodium dodecyl sulfate, and sodium dodecylbenzenesulfonate.

[0031] According to one specific embodiment, surface modifier I is γ-glycidoxypropyltrimethoxysilane.

[0032] According to a preferred embodiment, the modified mineral powder is obtained by a second reaction between surface modifier II and mineral powder at a mass ratio of 0.1-0.3:1. In this preferred embodiment, the high-temperature resistant interpenetrating network type reinforced plugging agent provided by the present invention has a high temperature resistance of 150°C and a colloidal strength reaching the level of a rigid colloidal material of grade I.

[0033] According to a preferred embodiment, the surface modifier II is selected from at least one of γ-glycidoxypropyltrimethoxysilane, aminopropyltriethoxysilane, sodium dodecyl sulfate, and sodium dodecylbenzenesulfonate.

[0034] According to a preferred embodiment, the mineral powder contains 35-60 wt% silicon dioxide, 20-35 wt% aluminum oxide, and more than 20 wt% calcium oxide.

[0035] According to a preferred embodiment, the water has a mineralization of 200,000 to 220,000.

[0036] According to one specific implementation, the water is oilfield water with a salinity of 210,000.

[0037] According to one specific embodiment, the modified nano-silica has an average particle diameter of 30-80 nm; the modified mineral powder has an average particle diameter of 30-80 μm.

[0038] According to a preferred embodiment, the crosslinking agent is selected from at least one of a combination of hexamethylenetetramine and hydroquinone, water-soluble phenolic resin, and urea-formaldehyde resin.

[0039] According to a preferred embodiment, the mass ratio of hexamethylenetetramine to hydroquinone in the combination of hexamethylenetetramine and hydroquinone is 1-1.5:1.

[0040] According to one specific embodiment, the hydroquinone is selected from at least one of hydroquinone, catechol, and resorcinol.

[0041] In this invention, a specific type of heat- and salt-resistant composite material (acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer and N-vinylpyrrolidone in a mass ratio of 1-2:1) is used as the main agent, and an external crosslinking agent is added for crosslinking to form a network gel system. Specific inorganic particles (modified nano-silica and modified mineral powder in a mass ratio of 1:2-5) are used as network fillers to form an interpenetrating network high-strength plugging agent with the network gel system, thereby improving the temperature resistance of the plugging agent.

[0042] As previously described, a second aspect of the present invention provides a method for preparing a high-temperature resistant interpenetrating network-type reinforced plugging agent, the method being carried out using the components of the composition described in the first aspect, comprising:

[0043] (1) The composite material is brought into contact with water for the first time to obtain mixture I;

[0044] (2) The mixture I is brought into a second contact with a crosslinking agent to obtain mixture II;

[0045] (3) The mixture II is subjected to a third contact and aging with inorganic particles in sequence to obtain the high-temperature resistant interpenetrating network type reinforced plugging agent.

[0046] According to a preferred embodiment, in step (1), the conditions for the first contact include: a rotation speed of 300-500 rpm and a time of 30-60 min.

[0047] According to a preferred embodiment, in step (2), the conditions for the second contact include: a rotation speed of 300-500 rpm and a time of 20-40 min.

[0048] According to a preferred embodiment, in step (3), the conditions for the third contact include: a temperature of 10-30°C, a rotation speed of 300-500 rpm, and a time of 30-60 min.

[0049] According to a preferred embodiment, in step (3), the aging conditions include: a temperature of 120-150°C and a time of 3-8 hours.

[0050] The modified nano-silica and modified mineral powder mentioned in this invention can be homemade or purchased. To obtain a sealing agent with higher high-temperature resistance and strength, the modified nano-silica is preferably prepared using a method including the following steps:

[0051] S1: Disperse nano-silica with an organic solvent by ultrasonication to obtain a dispersion;

[0052] S2: The dispersion and surface modifier I are refluxed at 70-100℃ for 10-20h to obtain the modified nano-silica.

[0053] In some embodiments, the organic solvent is toluene.

[0054] In some embodiments, the amount of the organic solvent used is 2-3 mL relative to 1 g of nano-silica.

[0055] The present invention does not impose any particular restrictions on the conditions for ultrasonic dispersion, and those skilled in the art can select them as needed.

[0056] The method for preparing the modified nano-silica of the present invention further includes a post-processing step. The present invention does not have special requirements for the post-processing, which can include separation, washing, drying, grinding, etc.; those skilled in the art can choose according to their needs. For example: the product after condensation and reflux is centrifuged, the supernatant is discarded, the precipitate is washed 3-5 times with anhydrous ethanol solution, the precipitate is dried in a vacuum drying oven for 24-30 hours, and then ground to obtain modified nano-silica with an average particle diameter of 30-80 nm.

[0057] The modified mineral powder described in this invention is preferably prepared using a method comprising the following steps:

[0058] S1: Soak the mineral powder in 85-95 (v / v)% ethanol for 1-2 hours, ultrasonically disperse it for 2-4 hours, and adjust the pH value to 3.5-4 to obtain a dispersion.

[0059] S2: The dispersion and surface modifier II are refluxed at 100-130℃ and 600-800 rpm for 2-6 hours to obtain the modified mineral powder.

[0060] The method for preparing the modified mineral powder of the present invention can also involve various post-processing operations known in the art, such as centrifugation, filtration, washing, drying, and grinding. The present invention does not impose any particular limitations on these operations, and those skilled in the art should not interpret them as limitations on the present invention. For example: the product after condensation and reflux is centrifuged, the supernatant is discarded, and the product is washed with ethanol solution and centrifuged 3-5 times. The centrifuged precipitate is then dried in a drying oven at 80-90℃ for 2-6 hours, and then ground to obtain modified mineral powder with an average particle diameter of 30-80 μm.

[0061] As previously described, a third aspect of the present invention provides a high-temperature resistant interpenetrating network type reinforced plugging agent prepared by the method described in the second aspect.

[0062] As previously stated, the fourth aspect of the present invention provides the application of the high-temperature resistant interpenetrating network type reinforced plugging agent described in the third aspect in the development of fractured-vuggy reservoirs.

[0063] The present invention will be described in detail below through examples. In the following examples, unless otherwise specified, the raw materials used are all commercially available products.

[0064] Unless otherwise specified, the reaction temperatures in the following examples are all carried out at room temperature, which refers to 25±2℃.

[0065] Nano-silica was purchased from Beijing Shenghe Haoyuan Technology Co., Ltd.

[0066] The nanofibers were purchased from Shandong Wanshengjia New Material Technology Co., Ltd.

[0067] γ-glycidoxypropyltrimethoxysilane (KH560) was purchased from Guangdong Shengke Biochemical Technology Co., Ltd., product number CL994379.

[0068] Mineral powder I was purchased from Zhuozhou Jingxi Petroleum Engineering Technology Co., Ltd., and contains 44 wt% silicon dioxide, 25 wt% aluminum oxide and 21 wt% calcium oxide, belonging to high-calcium fly ash.

[0069] Mineral powder II was purchased from Zhuozhou Jingxi Petroleum Engineering Technology Co., Ltd. It contains 44 wt% silica, 34 wt% alumina and 9.5 wt% calcium oxide, and is classified as low-calcium fly ash.

[0070] Acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer I was purchased from Dongying Liuhe Chemical Co., Ltd., and the weight-average molecular weight of acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer I is 6 million.

[0071] Acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer-II was purchased from Dongying Liuhe Chemical Co., Ltd., and the weight-average molecular weight of acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer-II is 8 million.

[0072] N-vinylpyrrolidone was purchased from Dongying Liuhe Chemical Co., Ltd.

[0073] The water in the oilfield comes from the Tarim River Oilfield and has a salinity of 210,000.

[0074] The laser particle size analyzer was purchased from Malvern Panaco Ltd. in the UK, model number Mastersizer 3000.

[0075] The freeze dryer was purchased from EYELA (Tokyo, Japan), model FDU2110.

[0076] The infrared spectrometer was purchased from Tianjin Gangdong Technology Development Co., Ltd., model FTIR-650.

[0077] Preparation Example 1

[0078] Preparation of modified nano-silica

[0079] (1) 10g of nano-silica was dried in an oven at 60℃ for 24 hours to obtain dried nano-silica;

[0080] (2) Add the dried nano-silica to a three-necked flask, add 25 mL of toluene solution to the three-necked flask, and place it in an ultrasonic disperser for 20 min at an ultrasonic frequency of 25 kHz to obtain a dispersion.

[0081] (3) The dispersion was refluxed in an oil bath at 80°C, and 0.4 g of γ-glycidyl oxypropyltrimethoxysilane was added dropwise while stirring. The stirring speed was 700 rpm. After the addition was completed, stirring and refluxing were continued for 12 h to obtain a mixed solution.

[0082] (4) The mixed solution is centrifuged, the supernatant is discarded, the precipitate is washed three times with anhydrous ethanol solution, the precipitate is dried in a vacuum drying oven at 80°C for 24 hours, and then ground until the average particle diameter is 50 nm to obtain modified nano silica.

[0083] Preparation Example 2

[0084] Preparation of modified mineral powder I

[0085] (1) Take 10g of mineral powder I and dry it in an oven at 60℃ for 24 hours to obtain dried mineral powder I;

[0086] (2) The dried mineral powder I was soaked in 90 (v / v) ethanol for 1.5 h and ultrasonically dispersed for 3 h at an ultrasonic frequency of 45 kHz. Then, glacial acetic acid was added to adjust the pH value to 3.5 to obtain a dispersion.

[0087] (3) Add 1g of γ-glycidoxypropyltrimethoxysilane to the dispersion, heat and reflux at 120°C, and stir at 700 rpm for 4h to obtain a mixed solution.

[0088] (4) The mixed solution is centrifuged, then washed with anhydrous ethanol and centrifuged 3 times until the centrifuged liquid is colorless and transparent. Then it is dried at 80°C for 24 hours and then ground until the average particle diameter is 60 μm to obtain modified mineral powder I.

[0089] Preparation Example 3

[0090] Preparation of modified mineral powder II

[0091] The procedure was carried out using a method similar to that used in Preparation Example 2, except that:

[0092] In step (1), 10g of mineral powder II was taken and dried in an oven at 60℃ for 24 hours to obtain dried mineral powder II;

[0093] The remaining steps were the same as in Preparation Example 2, resulting in modified mineral powder II with an average particle diameter of 60 μm.

[0094] Example 1

[0095] This embodiment illustrates that the high-temperature resistant interpenetrating network type reinforced plugging agent of the present invention is prepared according to the formulation and process parameters in Table 1 and the method described below;

[0096] (1) The oilfield water and the composite material are brought into contact for the first time to obtain mixture I;

[0097] (2) The mixture I and the crosslinking agent are brought into a second contact to obtain mixture II;

[0098] (3) The mixture II and the modified nano-silica and modified mineral powder are brought into a third contact to obtain mixture III;

[0099] (4) The mixture III is aged to obtain the high-temperature resistant interpenetrating network type reinforced plugging agent.

[0100] Examples 2 and 3 were carried out using a similar method to Example 1, except that the composition formulation and process parameters were different, as shown in Table 1.

[0101] Table 1 (each part by weight represents 1g)

[0102]

[0103] Example 4

[0104] This embodiment uses a method similar to that of Embodiment 1, except that an equal weight of modified mineral powder II is used instead of modified mineral powder I.

[0105] With all other conditions remaining the same, a high-temperature resistant interpenetrating network type reinforced plugging agent was obtained.

[0106] Comparative Example 1

[0107] This comparative example was carried out using a method similar to that of Example 1, except that an equal weight of nanofibers was used to replace the modified nano-silica I.

[0108] With all other conditions remaining the same, a high-temperature resistant interpenetrating network type reinforced plugging agent was obtained.

[0109] Comparative Example 2

[0110] This comparative example was conducted using a method similar to that of Example 1, except that the composite material was adjusted to 0.6g (acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer I was 0.4g, NVP was 0.2g), and the crosslinking agent was adjusted to 0.6g (urotropine was 0.3g, hydroquinone was 0.3g).

[0111] With all other conditions remaining the same, a high-temperature resistant interpenetrating network type reinforced plugging agent was obtained.

[0112] Comparative Example 3

[0113] This comparative example was carried out using a method similar to that of Example 1, except that an equal weight of acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer-II was used instead of acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer-I.

[0114] With all other conditions remaining the same, a high-temperature resistant interpenetrating network type reinforced plugging agent was obtained.

[0115] Comparative Example 4

[0116] This comparative example was carried out using a similar method to Example 1, except that an equal weight of acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer-I was used instead of NVP.

[0117] With all other conditions remaining the same, a high-temperature resistant interpenetrating network type reinforced plugging agent was obtained.

[0118] Comparative Example 5

[0119] This comparative example was conducted using a method similar to that of Example 1, except that the amount of modified nano-silica I was adjusted to 3g and the amount of modified mineral powder I was adjusted to 1g.

[0120] With all other conditions remaining the same, a high-temperature resistant interpenetrating network type reinforced plugging agent was obtained.

[0121] Comparative Example 6

[0122] This comparative example was carried out using a method similar to that of Example 1, except that no inorganic particles were added;

[0123] With all other conditions remaining the same, a high-temperature resistant interpenetrating network type reinforced plugging agent was obtained.

[0124] Test Example 1

[0125] This test example was used to determine the properties of the modified nano-silica prepared in Preparation Example 1. The specific results are shown below:

[0126] The average particle diameter was measured using a laser particle size analyzer.

[0127] The modified nano-silica prepared in Example 1 was measured by infrared spectroscopy, and the results are as follows: Figure 1 As shown, from Figure 1 It can be seen from the image that the silica grafted and modified with silane coupling agent KH560 has a thickness of 3421.15 cm⁻¹. -1 The absorption peak is due to the symmetric stretching vibration of the silanol group (-Si-OH), at 2875.64 cm⁻¹. -1 and 2942.4cm -1 A new organic absorption peak appeared at 1630.50 cm⁻¹, which are the characteristic absorption peaks of the methylene (-CH₂-) and methyl (-CH₃-) vibrations on KH560, respectively. -1 The absorption peak of the bending vibration of free water decreased to 1462.72 cm⁻¹. -1 The position represents the bending vibration and planar shear vibration of the methyl (-CH3-) and methylene (-CH2-) groups, at 1077.7 cm⁻¹. -1 The characteristic peak of the transverse and longitudinal symmetric stretching vibration of the siloxy group (-Si-O-Si) is 909.56 cm⁻¹. -1 A stretching vibration peak of epoxy groups appears nearby, at 799.25 cm⁻¹. -1 and 470.74cm -1 The peaks at these locations represent the symmetric contraction and bending vibrations of the silane oxygen group (-Si-O-Si), respectively. This indicates that the silane coupling agent KH560 was successfully grafted onto the silica surface.

[0128] Test Example 2

[0129] The following describes the performance of the high-temperature resistant interpenetrating network type reinforced plugging agents prepared in the above examples and comparative examples.

[0130] Dehydration rate test: The blocking agents (colloidal solution samples) prepared in the above examples and comparative examples were placed in a constant temperature chamber at 150°C until they were completely gelled. They were then kept in a closed environment at 150°C, and the dehydration of different samples was recorded for a certain period of time.

[0131] The calculation formula is S represents the dehydration rate (%), Vt represents the volume of the solution after dehydration (mL), and V represents the initial volume after gelation (mL). The dehydration rate test results are shown in Table 2.

[0132] Observation of the microstructure of the high-temperature resistant interpenetrating network reinforced plugging agent: Before testing, the high-temperature resistant interpenetrating network reinforced plugging agents prepared in the above examples and comparative examples were rapidly frozen in liquid nitrogen, transferred to a freeze dryer and freeze-dried in vacuum at -30°C for 24 hours. Then, the freeze-dried and dehydrated high-temperature resistant interpenetrating network reinforced plugging agent was surface-sputtered with gold to prepare the test sample, which was observed using a Quanta 450 scanning electron microscope.

[0133] Strength testing: Strain and frequency scans were performed at preset temperatures using the cone-plate system of the HAAKE RS600 rheometer. The shear stress ranged from 0.1 Pa to 100 Pa, and the frequency was maintained at 0.5 Hz (3.142 rad / s). The strength test results are shown in Table 3.

[0134] Table 2: Dehydration rate of high-temperature resistant interpenetrating network reinforced plugging agent

[0135]

[0136] As can be seen from Table 2, the temperature resistance of Comparative Example 1 decreased after nanofibers were used instead of modified nano-silica. Compared with the plugging agent prepared in Example 1, the high-temperature stability of the plugging agents prepared in Comparative Examples 2-4 all deteriorated. In Comparative Example 5, the high-temperature stability weakened after adjusting the ratio of modified nano-silica to modified mineral powder. In conjunction with the viscoelastic modulus in Table 3, although the storage modulus of the plugging agent prepared in Comparative Example 5 was significantly enhanced, the loss modulus decreased, and the colloidal surface exhibited brittleness.

[0137] Table 3

[0138]

[0139] As can be seen from Table 3, the strength of the plugging agent prepared in Comparative Example 2 decreased to the F level overall, with both the storage modulus and loss modulus being <1 Pa. The strength of the plugging agents prepared in Comparative Examples 3-4 was higher than that of the plugging agent prepared in Comparative Example 6, but both were lower than those prepared in Examples 1-4.

[0140] Figure 2 The image shows a scanning electron microscope (SEM) image of a high-temperature resistant interpenetrating network (IPN) reinforced plugging agent; among which, Figure 2 In the image, 'a' is a scanning electron microscope image of the high-temperature resistant interpenetrating network type reinforced plugging agent prepared in Example 1; Figure 2 In the image, b is a scanning electron microscope (SEM) image of the high-temperature resistant interpenetrating network (IPN) reinforced plugging agent prepared in Comparative Example 6; (The image is derived from...) Figure 2 a and Figure 2 As can be seen from the comparison in section b, both the gel without modified nano-SiO2 and modified mineral powder (Comparative Example 6) and the gel containing nano-SiO2 and mineral powder (Example 1) exhibit obvious three-dimensional network structures. The three-dimensional network structure of the gel system without modified nano-SiO2 and modified mineral powder is mostly a relatively loose network structure with no joints between the networks, while the network structure of the gel with modified nano-SiO2 and modified mineral powder is more compact, with obvious joints and granular spheres between the networks, which can improve the spatial stability of the network.

[0141] Figure 3The viscoelastic modulus test diagram is shown for the high-temperature interpenetrating network reinforced plugging agent prepared in Example 1. Figure 3 As can be seen, the storage modulus remains almost constant at low frequencies, but increases with frequency at medium to high frequencies, from 4.0 Pa to 332.2 Pa. This increase in storage modulus indicates that the high-temperature interpenetrating network (IPN) reinforced plugging agent possesses good elastic properties, exhibiting resistance to deformation or strong recovery ability after deformation at medium to high frequencies. Therefore, the higher the frequency, the better the elasticity of the high-temperature IPN reinforced plugging agent. From low to high frequencies, the loss modulus continuously increases, from 0.3 Pa to 49.7 Pa, and the rate of increase also increases with frequency. However, the value of the loss modulus remains lower than that of the storage modulus, indicating that the high-temperature IPN reinforced plugging agent primarily exhibits elastic properties. The viscoelastic ratio tanδ (the ratio of G” to G’) of the high-temperature interpenetrating network reinforced plugging agent was calculated at shear frequencies of 0.01Hz, 0.1Hz, 1Hz, and 10Hz. When δ = 0-10º, it is a strong elastic body; when δ = 10º-20º, it is an elastic body; when δ = 20º-40º, it is a viscoelastic body; and when δ > 40º, it is a viscous body. The high-temperature interpenetrating network reinforced plugging agent prepared in Example 1 has a phase angle δ of less than 10° at all four frequencies, indicating it is a strong elastic body with strong impact resistance, local damage resistance, and good erosion resistance after deformation.

[0142] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A high temperature resistant interpenetrating network type reinforced plugging agent composition, characterized in that, The composition contains a composite material, a cross-linking agent, inorganic particles and water; The content of the composite material is 0.8-1.5 parts by weight, the content of the cross-linking agent is 1.0-20 parts by weight, and the content of the inorganic particles is 2-8 parts by weight, relative to 100 parts by weight of water; The composite material is acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer and N-vinylpyrrolidone with a mass ratio of 1-2:1; The weight average molecular weight of the acrylamide-2-acrylamide-2-methylpropanesulfonic acid copolymer is 6-7.5 million; The inorganic particles are modified nano-silica and modified mineral powder with a mass ratio of 1:2-5; The modified nano-silica is obtained by a first reaction of a surface modifier I and nano-silica with a mass ratio of 0.01-0.1:1; the surface modifier I is γ-glycidoxypropyltrimethoxysilane; The modified mineral powder is obtained by a second reaction of a surface modifier II and mineral powder with a mass ratio of 0.1-0.3:1; the surface modifier II is γ-glycidoxypropyltrimethoxysilane; The mineral powder contains 35-60wt% of silicon dioxide, 20-35wt% of aluminum oxide and more than 20wt% of calcium oxide.

2. The composition of claim 1, wherein, The content of the composite material is 1.2-1.3 parts by weight, the content of the cross-linking agent is 1.2-15 parts by weight, and the content of the inorganic particles is 4-6 parts by weight, relative to 100 parts by weight of water.

3. The composition according to claim 1 or 2, characterized in that, The mineralization degree of the water is 200-220 thousand; And / or, the particle average diameter of the modified nano-silica is 30-80nm; the particle average diameter of the modified mineral powder is 30-80μm; And / or, the cross-linking agent is selected from at least one of a combination of urotropine and hydroquinone, water-soluble phenolic resin and urea-formaldehyde resin.

4. The composition of claim 3, wherein, The content of urotropine and hydroquinone in the combination of urotropine and hydroquinone is 1-1.5:1 in mass ratio.

5. A method of making a high temperature resistant interpenetrating network enhanced plugging agent, characterized in that, The method applies each component in the composition of any one of claims 1-4, comprising: (1) contacting the composite material with water to obtain a mixture I; (2) contacting the mixture I with a cross-linking agent to obtain a mixture II; (3) sequentially contacting and aging the mixture II with inorganic particles to obtain the high-temperature-resistant interpenetrating network reinforced plugging agent.

6. The method of claim 5, wherein, In step (1), the first contact condition includes a rotation speed of 300-500rpm and a time of 30-60min; And / or, in step (2), the second contact condition includes a rotation speed of 300-500rpm and a time of 20-40min; And / or, in step (3), the third contact condition includes a temperature of 10-30℃, a rotation speed of 300-500rpm and a time of 30-60min; And / or, in step (3), the aging condition includes a temperature of 120-150℃ and a time of 3-8h.

7. The high-temperature-resistant interpenetrating network reinforced plugging agent prepared by the method of claim 5 or 6.

8. The use of the high temperature resistant interpenetrating network enhanced plugging agent of claim 7 in the development of a fracture-cave type oil reservoir.

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