Biomass plugging agent as well as preparation method and application thereof
By preparing a biomass plugging agent grafted with hydroxypropyl methylcellulose ether and nano-silica, the problems of cumbersome unblocking process and harmful effects on the formation environment of existing plugging agents are solved, and the reversible change of temperature stimulus response and efficient plugging effect are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2024-11-14
- Publication Date
- 2026-05-15
AI Technical Summary
Existing heavy oil extraction sealing agents are cumbersome and complex to unblock during the process and are harmful to the formation environment, and cannot achieve reversible changes in response to temperature stimuli.
A biomass plugging agent was prepared by grafting hydroxypropyl methylcellulose ether with nano-silica. The reversible transformation from sol to gel was achieved by external temperature stimulation. It was used to seal off the flow in the transition zone and far well zone of heavy oil steam injection extraction.
Biomass plugging agent maintains high viscosity during multiple temperature rises and falls, achieving a formation environment-friendly sealing and plugging effect, eliminating the need for unblocking agents, and improving sealing and plugging efficiency.
Smart Images
Figure CN122037211A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of petroleum extraction, and in particular relates to a biomass plugging agent, its preparation method and application. Background Technology
[0002] my country is rich in heavy oil resources, accounting for over 20% of its total petroleum resources. Steam injection (>90%) is the primary extraction method for heavy oil. However, due to the large difference in steam / heavy oil mobility, strong reservoir heterogeneity, and severe steam channeling, the steam reach is small, resulting in low recovery rates. Therefore, controlling steam channeling is a key method to improve steam thermal utilization efficiency. During heavy oil steam injection extraction, three typical temperature field distributions exist: near-wellbore zone, transition zone, and far-wellbore zone. Appropriate channeling control agents should be placed in different channeling-sealing spaces during steam channeling control.
[0003] Chinese invention patent CN102181274B discloses a thixotropic chemical sealant, composed of iron-rich low-carbon sulfoaluminate, sodium-based bentonite, a water loss reducing agent, silica, cyclodextrin and / or starch, and the balance being water. It exhibits strong adhesion and thermal stability, good durability, crack resistance, high thixotropy, and anti-leakage ability.
[0004] Chinese invention patent application CN115725289A discloses a phenol-modified lignin-based blocking agent, its preparation method, and its application. The agent is composed of phenolic lignin, a thickener, a crosslinking agent, a modifier, a stabilizer, and water. This system features high blocking strength, wide applicability, and high blocking efficiency, and can effectively block vapor channeling for extended periods.
[0005] Chinese invention patent application CN117304898A discloses a polymeric gel sealant for heavy oil vapor injection and its preparation method. The sealant consists of nonionic polyacrylamide, nano-zirconium hydroxide particles, a phenolic crosslinking agent or a hexamethylenetetramine / hydroquinone mixed crosslinking agent, and the remainder being water. The polymeric gel sealant is stable for more than 180 days at a high temperature of 170°C, with a sealing rate >85%.
[0006] The aforementioned invention patents can solve the problem of steam channeling in heavy oil reservoirs, but the aforementioned sealing agents are all non-temperature-responsive and all require unblocking, which is a complicated process and poses certain hazards to the formation environment. Summary of the Invention
[0007] Objective: To address the technical problems of existing plugging agents, such as cumbersome and complex unblocking processes that are detrimental to the formation environment, this invention provides a biomass plugging agent, its preparation method, and its applications. The biomass plugging agent disclosed in this invention can undergo a reversible sol-to-gel transformation upon external temperature stimulation, is environmentally friendly, and maintains a gel viscosity greater than 10000 mPa·s after multiple temperature fluctuations. Furthermore, the biomass plugging agent disclosed in this invention does not require the use of unblocking agents during its application process and is environmentally friendly.
[0008] Technical solution: A biomass plugging agent, which is grafted from hydroxypropyl methylcellulose ether and nano-silica, wherein, based on the total mass of the biomass plugging agent, the hydroxypropyl methylcellulose ether accounts for 50-75% by weight, the nano-silica accounts for 25-50% by weight, and the viscosity-average molecular weight of the biomass plugging agent is 8000-16000.
[0009] A biomass plugging agent has the following general structural formula: in:
[0010] R is one of -H, -CH3, or -CH2CH(CH3)OH;
[0011] n is a positive integer, and its value ranges from 100 to 200.
[0012] The preparation method of the above-mentioned biomass plugging agent, by mass, includes the following steps:
[0013] Hydroxypropyl methylcellulose ether, γ-aminopropyltriethoxysilane, and nano-silica are dispersed in water in a certain proportion, then transferred into a reactor and stirred for a period of time at a certain reaction temperature. The supernatant is then obtained by centrifugation.
[0014] Preferably, the hydroxypropyl methylcellulose ether is prepared from biomass material through impurity removal and etherification treatment, wherein the biomass material is one or more of straw, rice husk, and rice husk.
[0015] Further, the preparation steps of the hydroxypropyl methylcellulose ether are as follows, based on parts by weight:
[0016] (1) Biomass material powder is obtained by washing, drying, crushing and passing the biomass material through a 20-200 mesh sieve;
[0017] (2) 10-30 parts of the material powder obtained in step (1) are mixed evenly with 200-400 parts of a strong alkali aqueous solution of a certain concentration in a reaction vessel and stirred at 70℃-80℃ for 1-2 hours. The mixture is then filtered and washed to obtain a brown powder.
[0018] (3) Mix 8-12 parts of the brown powder obtained in step (2) with 80-120 parts of a certain concentration of sodium chlorite aqueous solution in a reaction vessel, adjust the pH value to 6-7, and stir at 65℃-75℃ for 0.5-2h. After filtration, washing and drying, biomass material cellulose powder is obtained.
[0019] (4) 20-40 parts of biomass cellulose powder obtained in step (3), 15-25 parts of toluene, 15-50 parts of isopropanol, 20-40 parts of sodium hydroxide, 20-30 parts of propylene oxide and 40-60 parts of chloromethane are placed in a high-temperature and high-pressure reactor and etherified for at least 3 hours at 42-65℃, 65-75℃ and 85-92℃ respectively. The pH of the reaction solution is adjusted to 7-8. After centrifugation, the filter cake is washed and dried to obtain powdered hydroxypropyl methylcellulose ether.
[0020] Furthermore, the solute in the strong alkaline aqueous solution in step (2) is one of sodium hydroxide, potassium hydroxide, lithium hydroxide, or quaternary ammonium base, and the mass concentration of the strong alkaline aqueous solution in step (2) is 3%-10%, and / or
[0021] The mass concentration of the sodium chlorite aqueous solution in step (3) is 2-3%.
[0022] Preferably, the particle size of nano-silica is 20-400 nm.
[0023] Preferably, the mass ratio of hydroxypropyl methylcellulose ether, γ-aminopropyltriethoxysilane and nano-silica is (1-3):(0.5-2):1.
[0024] Preferably, the reaction temperature is at least 50°C, more preferably 50-70°C, and even more preferably 55-65°C.
[0025] Preferably, the reaction time is at least 4 hours, more preferably 4-8 hours, and even more preferably 4-6 hours.
[0026] Preferably, the stirring speed is at least 450 r / min.
[0027] Preferably, the centrifugation process requires the following:
[0028] The rotation speed should be at least 5000 rpm, preferably 5000-7000 rpm;
[0029] The centrifugation time should be at least 20 minutes, preferably 20-40 minutes.
[0030] Preferably, the water is one of ultrapure water, distilled water, deionized water, or tap water, with ultrapure water being the most preferred.
[0031] A biomass plugging agent is prepared by the above-described preparation method.
[0032] The aforementioned biomass plugging agents are used as plugging agents in transition zones and far-well zones during steam injection oil extraction.
[0033] Compared with the prior art, the beneficial effects of the present invention include:
[0034] This invention relates to a biomass plugging agent for heavy oil steam injection sealing by modifying hydroxypropyl methylcellulose ether obtained from biomass materials with nano-silica.
[0035] The biomass plugging agent prepared by this invention has good reversible cycle characteristics. It can achieve a reversible transformation from sol to gel after being stimulated by external temperature. It is environmentally friendly to the formation. The gel viscosity after multiple temperature rises and falls is greater than 10000 mPa·s. Attached Figure Description
[0036] Figure 1 Infrared spectra of cellulose, cellulose ether and biomass plugging agent prepared in Example 1.
[0037] Figure 2 The apparent viscosity of the biomass plugging agent prepared in Example 1 changes when subjected to alternating heating and cooling cycles at 30°C and 70°C.
[0038] Figure 3 The apparent viscosity of the biomass plugging agent prepared in Comparative Example 1 changes when subjected to alternating heating and cooling cycles at 30℃ and 70℃. Detailed Implementation
[0039] The specific embodiments of the present invention are described in detail below.
[0040] The "range" disclosed in this invention is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 10–50 is listed for a specific parameter, it is also expected that ranges of 10–40 and 20–50 are also included. Furthermore, if the minimum range values are 1 and 2, and the maximum range values are 3, 4, and 5, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, unless otherwise stated, the numerical range "a–b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0–5" means that all real numbers between "0–5" have been listed herein; "0–5" is merely a shortened representation of these numerical combinations.
[0041] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.
[0042] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.
[0043] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.
[0044] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.
[0045] Unless otherwise specified, the reaction will proceed under normal temperature and pressure conditions.
[0046] Unless otherwise specified, all parts or percentages are by weight or by weight percentage.
[0047] In this invention, all the substances used are known substances that can be purchased or synthesized by known methods.
[0048] In this invention, all the devices or equipment used are conventional devices or equipment known in the art and are readily available.
[0049] In the following examples, the γ-aminopropyltriethoxysilane, nano-silica, biomass materials, and required reagents are all commercially available.
[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0051] A biomass plugging agent is formed by grafting hydroxypropyl methylcellulose ether with nano-silica. Based on the total mass of the biomass plugging agent, the hydroxypropyl methylcellulose ether accounts for 50-75% by weight, the nano-silica accounts for 25-50% by weight, and the viscosity-average molecular weight of the biomass plugging agent is 8000-16000.
[0052] A biomass plugging agent has the following general structural formula: in:
[0053] R is one of -H, -CH3, or -CH2CH(CH3)OH;
[0054] n is a positive integer, and its value ranges from 100 to 200.
[0055] The preparation method of the above-mentioned biomass plugging agent, by mass, includes the following steps:
[0056] Hydroxypropyl methylcellulose ether, γ-aminopropyltriethoxysilane, and nano-silica are dispersed in water in a certain proportion, then transferred into a reactor and stirred for a period of time at a certain reaction temperature. The supernatant is then obtained by centrifugation.
[0057] Preferably, the hydroxypropyl methylcellulose ether is prepared from biomass material through impurity removal and etherification treatment, wherein the biomass material is one or more of straw, rice husk, and rice husk.
[0058] Further, the preparation steps of the hydroxypropyl methylcellulose ether are as follows, based on parts by weight:
[0059] (1) Biomass material powder is obtained by washing, drying, crushing and passing the biomass material through a 20-200 mesh sieve;
[0060] (2) 10-30 parts of the material powder obtained in step (1) are mixed evenly with 200-400 parts of a strong alkali aqueous solution of a certain concentration in a reaction vessel and stirred at 70℃-80℃ for 1-2 hours. The mixture is then filtered and washed to obtain a brown powder.
[0061] (3) Mix 8-12 parts of the brown powder obtained in step (2) with 80-120 parts of a certain concentration of sodium chlorite aqueous solution in a reaction vessel, adjust the pH value to 6-7, and stir at 65℃-75℃ for 0.5-2h. After filtration, washing and drying, biomass material cellulose powder is obtained.
[0062] (4) 20-40 parts of biomass cellulose powder obtained in step (3), 15-25 parts of toluene, 15-50 parts of isopropanol, 20-40 parts of sodium hydroxide, 20-30 parts of propylene oxide and 40-60 parts of chloromethane are placed in a high-temperature and high-pressure reactor and etherified for at least 3 hours at 42-65℃, 65-75℃ and 85-92℃ respectively. The pH of the reaction solution is adjusted to 7-8. After centrifugation, the filter cake is washed and dried to obtain powdered hydroxypropyl methylcellulose ether.
[0063] Furthermore, the solute in the strong alkaline aqueous solution in step (2) is one of sodium hydroxide, potassium hydroxide, lithium hydroxide, or quaternary ammonium base, and the mass concentration of the strong alkaline aqueous solution in step (2) is 3%-10%, and / or
[0064] The mass concentration of the sodium chlorite aqueous solution in step (3) is 2-3%.
[0065] Preferably, the particle size of nano-silica is 20-400 nm.
[0066] Preferably, the mass ratio of hydroxypropyl methylcellulose ether, γ-aminopropyltriethoxysilane and nano-silica is (1-3):(0.5-2):1.
[0067] Preferably, the reaction temperature is at least 50°C, more preferably 50-70°C, and even more preferably 55-65°C.
[0068] Preferably, the reaction time is at least 4 hours, more preferably 4-8 hours, and even more preferably 4-6 hours.
[0069] Preferably, the stirring speed is at least 450 r / min.
[0070] Preferably, the centrifugation process requires the following:
[0071] The rotation speed should be at least 5000 rpm, preferably 5000-7000 rpm;
[0072] The centrifugation time should be at least 20 minutes, preferably 20-40 minutes.
[0073] Preferably, the water is one of ultrapure water, distilled water, deionized water, or tap water, with ultrapure water being the most preferred.
[0074] A biomass plugging agent is prepared by the above-described preparation method.
[0075] The aforementioned biomass plugging agents are used as plugging agents in transition zones and far-well zones during steam injection oil extraction.
[0076] In one embodiment, a biomass plugging agent is formed by grafting hydroxypropyl methylcellulose ether with nano-silica, wherein, based on the total mass of the biomass plugging agent, the hydroxypropyl methylcellulose ether accounts for 50% by weight, the nano-silica accounts for 50% by weight, and the viscosity-average molecular weight of the biomass plugging agent is 8000.
[0077] A biomass plugging agent has the following general structural formula: in:
[0078] R is -H;
[0079] n is a positive integer, with a value of 100.
[0080] The preparation method of the above-mentioned biomass plugging agent, by mass, includes the following steps:
[0081] Hydroxypropyl methylcellulose ether, γ-aminopropyltriethoxysilane, and nano-silica are dispersed in water in a certain proportion, then transferred into a reactor and stirred for a period of time at a certain reaction temperature. The supernatant is then obtained by centrifugation.
[0082] Preferably, the hydroxypropyl methylcellulose ether is prepared from biomass material through impurity removal and etherification treatment, wherein the biomass material is straw.
[0083] Further, the preparation steps of the hydroxypropyl methylcellulose ether are as follows, based on parts by weight:
[0084] (1) Straw powder obtained by washing, drying, crushing and passing the straw through a 20-mesh sieve;
[0085] (2) 10 parts of the material powder obtained in step (1) are mixed evenly with 200 parts of a strong alkali aqueous solution of a certain concentration in a reaction vessel and stirred at 70°C for 2 hours. The mixture is then filtered and washed to obtain a brown powder.
[0086] (3) After mixing 8 parts of the brown powder obtained in step (2) with 80 parts of sodium chlorite aqueous solution of a certain concentration in a reaction vessel, the pH value was adjusted to 6, and the mixture was stirred at 65°C for 2 hours. After filtration, washing and drying, straw cellulose powder was obtained.
[0087] (4) 20 parts of straw cellulose powder, 15 parts of toluene, 15 parts of isopropanol, 20 parts of sodium hydroxide, 20 parts of propylene oxide and 40 parts of chloromethane obtained in step (3) are placed in a high temperature and high pressure reactor and etherified for 5 hours at 42℃, 65℃ and 85℃ respectively. The pH value of the reaction solution is adjusted to 7. After centrifugation, the filter cake is washed and dried to obtain powdered hydroxypropyl methylcellulose ether.
[0088] Furthermore, the solute in the strong alkaline aqueous solution in step (2) is sodium hydroxide, the mass concentration of the strong alkaline aqueous solution in step (2) is 3%, and / or
[0089] The sodium chlorite aqueous solution in step (3) has a mass concentration of 2%.
[0090] Preferably, the particle size of the nano-silica is 20 nm.
[0091] Preferably, the mass ratio of hydroxypropyl methylcellulose ether, γ-aminopropyltriethoxysilane and nano-silica is 1:0.5:1.
[0092] Preferably, the reaction temperature is 50°C.
[0093] Preferably, the reaction time is 8 hours. In another embodiment, the reaction time is 6 hours.
[0094] Preferably, the stirring speed is 450 r / min.
[0095] Preferably, the centrifugation process requires the following:
[0096] The rotation speed is 5000 rpm;
[0097] Centrifugation time was 40 minutes.
[0098] Preferably, the water is ultrapure water.
[0099] A biomass plugging agent is prepared by the above-described preparation method.
[0100] The aforementioned biomass plugging agents are used as plugging agents in transition zones and far-well zones during steam injection oil extraction.
[0101] In another embodiment, a biomass plugging agent is formed by grafting hydroxypropyl methylcellulose ether with nano-silica. Based on the total mass of the biomass plugging agent, the hydroxypropyl methylcellulose ether accounts for 75% by weight, the nano-silica accounts for 25% by weight, and the viscosity-average molecular weight of the biomass plugging agent is 16,000.
[0102] A biomass plugging agent has the following general structural formula: in:
[0103] R is -CH3;
[0104] n is a positive integer, with a value of 200.
[0105] The preparation method of the above-mentioned biomass plugging agent, by mass, includes the following steps:
[0106] Hydroxypropyl methylcellulose ether, γ-aminopropyltriethoxysilane, and nano-silica are dispersed in water in a certain proportion, then transferred into a reactor and stirred for a period of time at a certain reaction temperature. The supernatant is then obtained by centrifugation.
[0107] Preferably, the hydroxypropyl methylcellulose ether is prepared from biomass material through impurity removal and etherification treatment, wherein the biomass material is rice husk.
[0108] Further, the preparation steps of the hydroxypropyl methylcellulose ether are as follows, based on parts by weight:
[0109] (1) Rice husk powder is obtained by washing, drying, crushing and passing the rice husk through a 00 mesh sieve.
[0110] (2) 30 parts of the material powder obtained in step (1) are mixed evenly with 400 parts of a strong alkali aqueous solution of a certain concentration in a reaction vessel and stirred at 80°C for 1 hour. The mixture is then filtered and washed to obtain a brown powder.
[0111] (3) 12 parts of brown powder obtained in feeding step (2) are mixed with 120 parts of sodium chlorite aqueous solution of a certain concentration in a reaction vessel, the pH value is adjusted to 7, and the mixture is stirred at 75°C for 0.5h. After filtration, washing and drying, rice husk cellulose powder is obtained.
[0112] (4) 40 parts of rice husk cellulose powder, 25 parts of toluene, 50 parts of isopropanol, 40 parts of sodium hydroxide, 30 parts of propylene oxide and 60 parts of chloromethane obtained in step (3) were placed in a high temperature and high pressure reactor and etherified for 3 hours at 65℃, 75℃ and 92℃ respectively. The pH value of the reaction solution was adjusted to 8. After centrifugation, the filter cake was washed and dried to obtain powdered hydroxypropyl methylcellulose ether.
[0113] Furthermore, the solute in the strong alkaline aqueous solution in step (2) is potassium hydroxide, the mass concentration of the strong alkaline aqueous solution in step (2) is 10%, and / or
[0114] The mass concentration of the sodium chlorite aqueous solution in step (3) is %.
[0115] Preferably, the particle size of the nano-silica is 400 nm.
[0116] Preferably, the mass ratio of hydroxypropyl methylcellulose ether, γ-aminopropyltriethoxysilane, and nano-silica is 3:2:1.
[0117] Preferably, the reaction temperature is 70°C. In another embodiment, the reaction temperature is 65°C.
[0118] Preferably, the reaction time is 4 hours.
[0119] Preferably, the stirring speed is 500 r / min.
[0120] Preferably, the centrifugation process requires the following:
[0121] 7000 rpm;
[0122] Centrifugation time was 20 minutes.
[0123] Preferably, the water is distilled water.
[0124] A biomass plugging agent is prepared by the above-described preparation method.
[0125] The aforementioned biomass plugging agents are used as plugging agents in transition zones and far-well zones during steam injection oil extraction.
[0126] In another embodiment, a biomass plugging agent is formed by grafting hydroxypropyl methylcellulose ether with nano-silica. Based on the total mass of the biomass plugging agent, the hydroxypropyl methylcellulose ether accounts for 60% by weight, the nano-silica accounts for 40% by weight, and the viscosity-average molecular weight of the biomass plugging agent is 11,000.
[0127] A biomass plugging agent has the following general structural formula: in:
[0128] R is -CH2CH(CH3)OH;
[0129] n is a positive integer, with a value of 150.
[0130] The preparation method of the above-mentioned biomass plugging agent, by mass, includes the following steps:
[0131] Hydroxypropyl methylcellulose ether, γ-aminopropyltriethoxysilane, and nano-silica are dispersed in water in a certain proportion, then transferred into a reactor and stirred for a period of time at a certain reaction temperature. The supernatant is then obtained by centrifugation.
[0132] Preferably, the hydroxypropyl methylcellulose ether is prepared from biomass material through impurity removal and etherification treatment, wherein the biomass material is rice husk. In another embodiment, the hydroxypropyl methylcellulose ether is prepared from biomass material through impurity removal and etherification treatment, wherein the biomass material is a mixture of straw, rice husk, and rice husk in equal mass ratios.
[0133] Further, the preparation steps of the hydroxypropyl methylcellulose ether are as follows, based on parts by weight:
[0134] (1) The rice husk powder obtained by washing, drying, crushing and passing through a 100-mesh sieve;
[0135] (2) 20 parts of the material powder obtained in step (1) are mixed evenly with 300 parts of a strong alkali aqueous solution of a certain concentration in a reaction vessel and stirred at 75°C for 1.5 hours. The mixture is then filtered and washed to obtain a brown powder.
[0136] (3) After mixing 10 parts of the brown powder obtained in step (2) with 100 parts of a certain concentration of sodium chlorite aqueous solution in a reaction vessel, the pH value is adjusted to 6.5 and then stirred at 70°C for 1 hour. After filtration, washing and drying, rice husk cellulose powder is obtained.
[0137] (4) 30 parts of rice husk cellulose powder, 20 parts of toluene, 20 parts of isopropanol, 25 parts of sodium hydroxide, 25 parts of propylene oxide and 48 parts of chloromethane obtained in step (3) were etherified in a high temperature and high pressure reactor at 45℃, 70℃ and 87℃ for 4 hours respectively. The pH value of the reaction solution was adjusted to 7.5. After centrifugation, the filter cake was washed and dried to obtain powdered hydroxypropyl methylcellulose ether.
[0138] Furthermore, the solute in the strong alkaline aqueous solution in step (2) is lithium hydroxide, the mass concentration of the strong alkaline aqueous solution in step (2) is 8%, and / or
[0139] The sodium chlorite aqueous solution in step (3) has a mass concentration of 2.2%.
[0140] In another embodiment, the solute in the strong base aqueous solution in step (2) is a quaternary ammonium base, the mass concentration of the strong base aqueous solution in step (2) is 5%, and / or
[0141] The sodium chlorite aqueous solution in step (3) has a mass concentration of 2.6%.
[0142] Preferably, the particle size of the nano-silica is 200 nm.
[0143] Preferably, the mass ratio of hydroxypropyl methylcellulose ether, γ-aminopropyltriethoxysilane, and nano-silica is 1.5:1:1.
[0144] Preferably, the reaction temperature is 60°C.
[0145] Preferably, the reaction time is 5 hours.
[0146] Preferably, the stirring speed is 550 r / min.
[0147] Preferably, the centrifugation process requires the following:
[0148] The rotation speed is 6000 rpm;
[0149] Centrifugation time was 30 minutes.
[0150] Preferably, the water is deionized water. In another embodiment, the water is tap water.
[0151] A biomass plugging agent is prepared by the above-described preparation method.
[0152] The aforementioned biomass plugging agents are used as plugging agents in transition zones and far-well zones during steam injection oil extraction.
[0153] Example 1
[0154] The preparation method of biomass plugging agent includes the following steps:
[0155] 1.5 g of hydroxypropyl methylcellulose ether, 0.7 g of γ-aminopropyltriethoxysilane and 0.7 g of nano-silica were uniformly dispersed in 100 mL of ultrapure water and transferred to a 250 mL round-bottom flask. The mixture was magnetically stirred at 65 °C for 4 h. After centrifugation at 6000 rpm for 30 min, the supernatant was used as a biomass plugging agent.
[0156] Furthermore, the particle size of the nano-silica is 20 nm.
[0157] Furthermore, taking corn stalks as a biomass material as an example, the preparation process of hydroxypropyl methylcellulose ether is as follows:
[0158] (1) Wash and dry the corn stalks, then crush them and pass them through a 20-mesh sieve to obtain corn stalk powder;
[0159] (2) The corn stalk powder obtained in step (1) is mixed evenly with 300g of 5% sodium hydroxide aqueous solution in a 500mL round bottom flask and stirred at 70℃ for 2h. The mixture is then filtered and washed to obtain brown powder.
[0160] (3) After mixing 10g of brown powder obtained in step (2) with 100g of 2.2% sodium chlorite solution in a 500mL round-bottom flask, the pH value was adjusted to within 6, and the mixture was stirred at 70℃ for 0.5h. After filtration, washing and drying, light brown corn stalk cellulose powder was obtained.
[0161] (5) 30g of corn stalk cellulose powder, 20g of toluene, 20g of isopropanol, 30g of sodium hydroxide, 22g of propylene oxide and 44g of chloromethane obtained in step (4) were placed in a 1L high-temperature and high-pressure reactor and etherified at 55℃, 70℃ and 85℃ for 3h respectively. The pH of the reaction solution was adjusted to 7. After centrifugation, the filter cake was washed and dried to obtain off-white powdered hydroxypropyl methylcellulose ether.
[0162] A biomass plugging agent is prepared by the above-described preparation method.
[0163] The aforementioned biomass plugging agents are used as plugging agents in transition zones and far-well zones during steam injection oil extraction.
[0164] After testing, the apparent viscosity and thixotropic temperature of the biomass plugging agent at 30°C were 93.71 mPa·s and 69.72°C, respectively.
[0165] Example 2
[0166] The preparation method of biomass plugging agent includes the following steps:
[0167] 2g of hydroxypropyl methylcellulose ether, 0.9g of γ-aminopropyltriethoxysilane and 1.2g of nano-silica were uniformly dispersed in 100mL of ultrapure water and transferred to a 250mL round-bottom flask. The mixture was magnetically stirred at 70℃ for 3h. After centrifugation at 6000rpm for 30min, the supernatant was used as a biomass plugging agent.
[0168] Furthermore, the particle size of the nano-silica is 400 nm.
[0169] Furthermore, taking corn stalks as a biomass material as an example, the preparation steps of hydroxypropyl methylcellulose ether are as follows:
[0170] (1) Wash and dry the corn stalks, crush them and pass them through a 100-mesh sieve to obtain corn stalk powder;
[0171] (2) 20g of corn stalk powder obtained in feeding step (1) and 300g of 5% sodium hydroxide aqueous solution are mixed evenly in a 500mL round bottom flask and stirred at 75℃ for 2h. The brown powder is obtained by filtration and washing.
[0172] (3) 10g of brown powder obtained in feeding step (2) and 100g of 2.2% sodium chlorite solution are mixed evenly in a 500mL round bottom flask, the pH value is adjusted to 7, and the mixture is stirred at 65℃ for 1h. After filtration, washing and drying, light brown corn stalk cellulose powder is obtained.
[0173] (4) 30g of corn stalk cellulose powder, 20g of toluene, 20g of isopropanol, 20g of sodium hydroxide, 20g of propylene oxide and 20g of chloromethane obtained in step (3) were placed in a high-temperature and high-pressure reactor with a volume of 1L and etherified at 65℃, 75℃ and 92℃ for 3h respectively. The pH value of the reaction solution was adjusted to 8. After centrifugation, the filter cake was washed and dried to obtain off-white powdered hydroxypropyl methylcellulose ether.
[0174] After testing, the apparent viscosity and thixotropic temperature of the biomass plugging agent at 30°C were 301.70 mPa·s and 54.73°C, respectively.
[0175] A biomass plugging agent is prepared by the above-described preparation method.
[0176] The aforementioned biomass plugging agents are used as plugging agents in transition zones and far-well zones during steam injection oil extraction.
[0177] Infrared spectroscopy tests were performed on the corn straw cellulose, hydroxypropyl methylcellulose ether, and biomass plugging agent used in Example 2. The results are as follows: Figure 1 As shown. Figure 1 This indicates that a biomass plugging agent has been successfully prepared.
[0178] Example 3
[0179] The preparation method of biomass plugging agent includes the following steps:
[0180] 0.5 g of hydroxypropyl methylcellulose ether, 0.5 g of γ-aminopropyltriethoxysilane and 0.3 g of nano-silica were uniformly dispersed in 100 mL of tap water and then transferred to a 250 mL round-bottom flask. The mixture was stirred at 65 °C for 4 h and centrifuged at 6000 rpm for 30 min. The supernatant was then used as a biomass plugging agent.
[0181] Furthermore, the particle size of the nano-silica is 200 nm.
[0182] Furthermore, taking rice husk as a biomass material as an example, the preparation steps of hydroxypropyl methylcellulose ether are as follows:
[0183] (1) Wash and dry the rice husks, crush them, and pass them through a 100-mesh sieve to obtain rice husk powder;
[0184] (2) 20g of rice husk powder obtained in feeding step (1) and 300g of 5% sodium hydroxide aqueous solution are mixed evenly in a 500mL round bottom flask and stirred at 75℃ for 2h. After filtration and washing, a light brown powder is obtained.
[0185] (3) 10g of light brown powder obtained in feeding step (2) and 100g of 2.2% sodium chlorite solution are mixed evenly in a 500mL round bottom flask, the pH value is adjusted to 6, and the mixture is stirred at 70℃ for 0.5h. After filtration, washing and drying, light brown rice husk cellulose powder is obtained.
[0186] (4) 30g of rice husk cellulose powder, 20g of toluene, 20g of isopropanol, 30g of sodium hydroxide, 20g of propylene oxide and 40g of chloromethane obtained in step (3) were placed in a high-temperature and high-pressure reactor with a volume of 1L and etherified at 55℃, 70℃ and 85℃ for 3h respectively. The pH value of the reaction solution was adjusted to within 7. After centrifugation, the filter cake was washed and dried to obtain white powdered hydroxypropyl methylcellulose ether.
[0187] A biomass plugging agent is prepared by the above-described preparation method.
[0188] The aforementioned biomass plugging agents are used as plugging agents in transition zones and far-well zones during steam injection oil extraction.
[0189] After testing, the apparent viscosity and thixotropic temperature of the biomass plugging agent prepared in Example 3 at 30°C were 5.98 mPa·s and 78.34°C, respectively.
[0190] Example 4
[0191] The preparation method of biomass plugging agent includes the following steps:
[0192] 2g of hydroxypropyl methylcellulose ether, 2g of γ-aminopropyltriethoxysilane and 2g of nano-silica were uniformly dispersed in 100mL of deionized water and then transferred to a 250mL round-bottom flask. The mixture was stirred and reacted at 60℃ for 5h. The supernatant was collected by centrifugation and used as a biomass plugging agent.
[0193] Furthermore, the particle size of the nano-silica is 100 nm.
[0194] Furthermore, taking rice husk as a biomass material as an example, the preparation steps of hydroxypropyl methylcellulose ether are as follows:
[0195] (1) Wash and dry the rice husks, crush them, and pass them through a 50-mesh sieve to obtain rice husk powder.
[0196] (2) 20g of rice husk powder obtained in feeding step (1) and 300g of 5% sodium hydroxide aqueous solution are mixed evenly in a 500mL round bottom flask and stirred at 70℃ for 2h. The brown powder is obtained by filtration and washing.
[0197] (3) 10g of brown powder obtained in feeding step (2) and 100g of 2.2% sodium chlorite solution are mixed evenly in a 500mL round bottom flask, the pH value is adjusted to 7, and the mixture is stirred at 70℃ for 2.0h. After filtration, washing and drying, rice husk cellulose powder is obtained.
[0198] (4) 20g of rice husk cellulose powder, 15g of toluene, 15g of isopropanol, 15g of sodium hydroxide, 12g of propylene oxide and 35g of chloromethane obtained in step (3) were placed in a high-temperature and high-pressure reactor with a volume of 1L and etherified at 42℃, 65℃ and 85℃ for 3h respectively. The pH value of the reaction solution was adjusted to 8. After centrifugation, the filter cake was washed and dried to obtain white powdered hydroxypropyl methylcellulose ether.
[0199] A biomass plugging agent is prepared by the above-described preparation method.
[0200] The aforementioned biomass plugging agents are used as plugging agents in transition zones and far-well zones during steam injection oil extraction.
[0201] After testing, the apparent viscosity and thixotropic temperature of the biomass plugging agent prepared in Example 4 at 30°C were 35.92 mPa·s and 74.12°C, respectively.
[0202] Example 5
[0203] The preparation method of biomass plugging agent includes the following steps:
[0204] (1) Preparation of biomass plugging agent
[0205] 1 g of hydroxypropyl methylcellulose ether, 2 g of γ-aminopropyltriethoxysilane and 1 g of nano-silica were uniformly dispersed in 100 mL of distilled water and transferred to a 250 mL round-bottom flask. The mixture was stirred at 60 °C for 5 h and centrifuged at 6000 rpm for 30 min. The supernatant was then used as a biomass plugging agent.
[0206] Furthermore, the particle size of the nano-silica is 250 nm.
[0207] Furthermore, taking corn stalks as a biomass material as an example, the preparation steps of hydroxypropyl methylcellulose ether are as follows:
[0208] (1) Wash and dry the corn stalks, crush them, and pass them through a 200-mesh sieve to obtain corn stalk powder;
[0209] (2) 20g of corn stalk powder obtained in feeding step (1) and 300g of 5% sodium hydroxide aqueous solution are mixed evenly in a 500mL round bottom flask and stirred at 80℃ for 1h. The brown powder is obtained by filtration and washing.
[0210] (3) 10g of brown powder obtained in feeding step (2) and 100g of 2.2% sodium chlorite solution are mixed evenly in a 500mL round bottom flask, the pH value is adjusted to 6, and the mixture is stirred at 75℃ for 0.5h. After filtration, washing and drying, light brown corn stalk cellulose powder is obtained.
[0211] (4) 30g of corn stalk cellulose powder, 20g of toluene, 20g of isopropanol, 30g of sodium hydroxide, 30g of propylene oxide and 60g of chloromethane were added to a 1L high-temperature and high-pressure reactor and etherified at 55℃, 75℃ and 85℃ for 3h respectively. The pH of the reaction solution was adjusted to within 7. After centrifugation, the filter cake was washed and dried to obtain off-white powdery hydroxypropyl methylcellulose ether.
[0212] A biomass plugging agent is prepared by the above-described preparation method.
[0213] The aforementioned biomass plugging agents are used as plugging agents in transition zones and far-well zones during steam injection oil extraction.
[0214] After testing, the apparent viscosity and thixotropic temperature of the biomass plugging agent prepared in Example 5 at 30°C were 20.71 mPa·s and 75.08°C, respectively.
[0215] Comparative Example 1
[0216] The preparation method of biomass plugging agent includes the following steps:
[0217] 1.5 g of hydroxypropyl methylcellulose ether was uniformly dispersed in 100 mL of ultrapure water and then transferred to a 250 mL round-bottom flask. The mixture was stirred at 65 °C for 4 h and centrifuged at 6000 rpm for 30 min. The supernatant was then used as a biomass plugging agent.
[0218] Furthermore, taking corn stalks as a biomass material as an example, the preparation method of hydroxypropyl methylcellulose ether is as follows:
[0219] (1) Wash and dry the corn stalks, crush them, and pass them through a 20-mesh sieve to obtain corn stalk powder;
[0220] (2) 20g of corn stalk powder obtained in feeding step (1) and 300g of 5% sodium hydroxide aqueous solution are mixed evenly in a 500mL round bottom flask and stirred at 70℃ for 2h. The brown powder is obtained by filtration and washing.
[0221] (3) 10g of brown powder and 100g of 2.2% sodium chlorite solution were mixed evenly in a 500mL round-bottom flask, and the pH value was adjusted to within 6. The mixture was then stirred at 70℃ for 0.5h. After filtration, washing and drying, light brown corn stalk cellulose powder was obtained.
[0222] (4) 30g of corn stalk cellulose powder, 20g of toluene, 20g of isopropanol, 30g of sodium hydroxide, 22g of propylene oxide and 44g of chloromethane were added to a 1L high-temperature and high-pressure reactor and etherified at 55℃, 70℃ and 85℃ for 3h respectively. The pH of the reaction solution was adjusted to within 7. After centrifugation, the filter cake was washed and dried to obtain off-white powdery hydroxypropyl methylcellulose ether.
[0223] After testing, the apparent viscosity and thixotropic temperature of the biomass plugging agent in Comparative Example 1 at 30℃ were 87.45 mPa·s and 70.20℃, respectively.
[0224] Test Example 1
[0225] The temperature-response thixotropic properties of biomass plugging agents were evaluated using a high-temperature, high-pressure rheometer.
[0226] A 1.5% temperature-responsive nanohybrid gel system was prepared, and the change in apparent viscosity of the gel system during alternating heating and cooling cycles (30-70℃) was measured. The oscillation frequency was set to 1.0 Hz, the yield stress to 1 Pa, and the heating and cooling time interval to 0.5 h. Experimental data are as follows: Figure 2 and Figure 3 As shown.
[0227] like Figure 2 As shown, the biomass plugging agent prepared in Example 1 has sensitive temperature-responsive thixotropic properties. The system exhibits a low viscosity fluid of 80-100 mPa·s at 30°C, and a high-strength gel with an apparent viscosity greater than 100,000 mPa·s after being heated to 70°C.
[0228] like Figure 2 and Figure 3 As shown, compared with the biomass plugging agent prepared in Example 1, the viscosity of Example 1 decreased less after multiple temperature-responsive thixotropic reactions. Furthermore, the apparent viscosity of the biomass plugging agent prepared in Example 1 after gelation was higher than that of Comparative Example 1, indicating that the biomass plugging agent prepared in Example 1 has better gel strength and temperature-responsive thixotropic properties.
[0229] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.
Claims
1. A biomass plugging agent, characterized in that, It is composed of hydroxypropyl methylcellulose ether grafted with nano-silica. Based on the total mass of the biomass plugging agent, the hydroxypropyl methylcellulose ether accounts for 50-75% by weight, the nano-silica accounts for 25-50% by weight, and the viscosity-average molecular weight of the biomass plugging agent is 8000-16000.
2. A biomass plugging agent, characterized in that, Its general structural formula is as follows: in: R is one of -H, -CH3, or -CH2CH(CH3)OH; n is a positive integer, and its value ranges from 100 to 200.
3. A method for preparing the biomass plugging agent according to claim 1 or 2, characterized in that, In terms of mass, it includes the following steps: Hydroxypropyl methylcellulose ether, γ-aminopropyltriethoxysilane, and nano-silica are dispersed in water in a certain proportion, then transferred into a reactor and stirred for a period of time at a certain reaction temperature. The supernatant is then obtained by centrifugation.
4. The method for preparing a biomass plugging agent as described in claim 3, characterized in that, The hydroxypropyl methylcellulose ether is prepared from biomass materials through impurity removal and etherification treatment, wherein the biomass materials are one or more of straw, rice husks, and rice husks.
5. The method for preparing a biomass plugging agent as described in claim 4, characterized in that, The preparation steps of the hydroxypropyl methylcellulose ether are as follows, based on parts by weight: (1) Biomass material powder is obtained by washing, drying, crushing and passing the biomass material through a 20-200 mesh sieve; (2) 10-30 parts of the material powder obtained in step (1) are mixed evenly with 200-400 parts of a strong alkali aqueous solution of a certain concentration in a reaction vessel and stirred at 70℃-80℃ for 1-2 hours. The mixture is then filtered and washed to obtain a brown powder. (3) Mix 8-12 parts of the brown powder obtained in step (2) with 80-120 parts of a certain concentration of sodium chlorite aqueous solution in a reaction vessel, adjust the pH value to 6-7, and stir at 65℃-75℃ for 0.5-2h. After filtration, washing and drying, biomass material cellulose powder is obtained. (4) 20-40 parts of biomass cellulose powder obtained in step (3), 15-25 parts of toluene, 15-50 parts of isopropanol, 20-40 parts of sodium hydroxide, 20-30 parts of propylene oxide and 40-60 parts of chloromethane are placed in a high-temperature and high-pressure reactor and etherified for at least 3 hours at 42-65℃, 65-75℃ and 85-92℃ respectively. The pH of the reaction solution is adjusted to 7-8. After centrifugation, the filter cake is washed and dried to obtain powdered hydroxypropyl methylcellulose ether.
6. The method for preparing a biomass plugging agent as described in claim 5, characterized in that, The solute in the strong alkaline aqueous solution in step (2) is one of sodium hydroxide, potassium hydroxide, lithium hydroxide, or quaternary ammonium base, and the mass concentration of the strong alkaline aqueous solution in step (2) is 3%-10%, and / or The mass concentration of the sodium chlorite aqueous solution in step (3) is 2-3%.
7. The method for preparing a biomass plugging agent as described in claim 6, characterized in that, The particle size of nano-silica is 20-400 nm, and / or The mass ratio of hydroxypropyl methylcellulose ether, γ-aminopropyltriethoxysilane and nano silica is (1-3):(0.5-2):
1.
8. The method for preparing a biomass plugging agent as described in claim 6, characterized in that, The reaction temperature is at least 50°C, preferably 50-70°C, more preferably 55-65°C, and / or The reaction time is at least 4 hours, preferably 4-8 hours, and more preferably 4-6 hours.
9. The method for preparing a biomass plugging agent as described in claim 6, characterized in that, The stirring speed is at least 450 r / min, and / or The centrifugation process requirements are as follows: The rotation speed should be at least 5000 rpm, preferably 5000-7000 rpm; The centrifugation time should be at least 20 minutes, preferably 20-40 minutes.
10. The method for preparing a biomass plugging agent as described in claim 6, characterized in that, The water is one of ultrapure water, distilled water, deionized water, or tap water, with ultrapure water being preferred.
11. A biomass plugging agent, prepared by the preparation method according to any one of claims 3-10.
12. The application of the biomass plugging agent according to any one of claims 1, 2 or 11 as a plugging agent for transition zones and far-well zones during steam injection oil extraction.