CN115490882A - Temperature response type gel plugging agent and preparation method and application thereof - Google Patents

Temperature response type gel plugging agent and preparation method and application thereof Download PDF

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CN115490882A
CN115490882A CN202110678564.0A CN202110678564A CN115490882A CN 115490882 A CN115490882 A CN 115490882A CN 202110678564 A CN202110678564 A CN 202110678564A CN 115490882 A CN115490882 A CN 115490882A
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chitosan
solution
temperature
hydroxybutyl
alkalized
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武俊文
王海波
张汝生
杨立红
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China Petroleum and Chemical Corp
Sinopec Exploration and Production Research Institute
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China Petroleum and Chemical Corp
Sinopec Exploration and Production Research Institute
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/02—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
    • C08J3/03—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in aqueous media
    • C08J3/075—Macromolecular gels
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
    • C08B37/00—Preparation of polysaccharides not provided for in groups C08B1/00 - C08B35/00; Derivatives thereof
    • C08B37/0006—Homoglycans, i.e. polysaccharides having a main chain consisting of one single sugar, e.g. colominic acid
    • C08B37/0024—Homoglycans, i.e. polysaccharides having a main chain consisting of one single sugar, e.g. colominic acid beta-D-Glucans; (beta-1,3)-D-Glucans, e.g. paramylon, coriolan, sclerotan, pachyman, callose, scleroglucan, schizophyllan, laminaran, lentinan or curdlan; (beta-1,6)-D-Glucans, e.g. pustulan; (beta-1,4)-D-Glucans; (beta-1,3)(beta-1,4)-D-Glucans, e.g. lichenan; Derivatives thereof
    • C08B37/0027—2-Acetamido-2-deoxy-beta-glucans; Derivatives thereof
    • C08B37/003—Chitin, i.e. 2-acetamido-2-deoxy-(beta-1,4)-D-glucan or N-acetyl-beta-1,4-D-glucosamine; Chitosan, i.e. deacetylated product of chitin or (beta-1,4)-D-glucosamine; Derivatives thereof
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/42—Compositions for cementing, e.g. for cementing casings into boreholes; Compositions for plugging, e.g. for killing wells
    • C09K8/44—Compositions for cementing, e.g. for cementing casings into boreholes; Compositions for plugging, e.g. for killing wells containing organic binders only
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2305/00—Characterised by the use of polysaccharides or of their derivatives not provided for in groups C08J2301/00 or C08J2303/00
    • C08J2305/08—Chitin; Chondroitin sulfate; Hyaluronic acid; Derivatives thereof

Abstract

The invention provides a method for preparing a temperature response type gel plugging agent, the temperature response type gel plugging agent and application thereof, wherein the method comprises the following steps: adding hydroxybutyl chitosan into water, dissolving, heating and standing to obtain a temperature response type gel plugging agent; wherein the mass fraction of the hydroxybutyl chitosan is 0.05-0.8%, preferably 0.2-0.6%, more preferably 0.3-0.5%. The gel system is prepared by physical crosslinking without adding any crosslinking agent, and the problems of phase separation precipitation, difficult injection and poor gelling capability caused by flushing and diffusion of the conventional gel plugging agent at present are solved, so that the purposes of deep liquid flow diversion, swept volume expansion and recovery ratio improvement are achieved.

Description

Temperature response type gel plugging agent and preparation method and application thereof
Technical Field
The invention relates to the technical field of oilfield chemistry, in particular to a temperature response type gel plugging agent and a preparation method and application thereof.
Background
In the oil field developed by water injection, due to the heterogeneity of the stratum and the complexity of the reservoir stratum, the heterogeneity of a water injection section is increased along with the increase of the water injection amount, so that a large amount of water is discharged from the oil well. At present, most of domestic oil fields are developed in the middle and later stages, the average water content of the oil well reaches more than 80%, and the water content of some old oil fields in the eastern region reaches more than 90%, so that the workload and the working difficulty of water shutoff and profile control are increased. The polyacrylamide gel water plugging profile control agent has the advantages that the polyacrylamide gel water plugging profile control agent is widely accepted by high-water-content and large-pore-channel oil fields, becomes an important means for deep excavation and yield stabilization of the high-water-content oil fields, is widely used in oil fields such as township, victory and the like, and obtains good application effects.
The plugging mechanism of the polyacrylamide gel is that a plurality of active groups are arranged on a polyacrylamide molecular chain, and the active groups are crosslinked with a crosslinking agent to form a net structure. This network structure can contain water in a lattice structure to form a gel with viscoelastic properties. The gel forms physical blockage in the middle of the pore medium of the stratum, and the aim of blocking is achieved by preventing water flow or changing the water flow direction. The polymer gel is mainly used for water blocking by physical blocking and has the functions of adsorption and dynamic trapping. At present, the conventional polyacrylamide gel gelation gellant is easy to cause phase separation and precipitation of the gellant due to the dilution and diffusion effects of formation water in the injection process, so that the injection is difficult and the gelling capacity of the gellant is reduced. At present, methods for improving dilution and diffusion of polyacrylamide gel plugging agents are reported, mainly the influence of dilution and diffusion is reduced by shortening the gelling time of the gel waiting liquid, but the negative influence brought by shortening the gel waiting time is that the gel waiting liquid cannot enter deep parts of the stratum to perform deep plugging adjustment, so that the plugging adjustment effect is greatly reduced.
In conclusion, the conventional polyacrylamide gel has the problems of difficult injection and low hybridization capacity, and the plugging and adjusting effect is influenced.
Disclosure of Invention
In view of the background technology, the invention provides a temperature response type gel plugging agent, a preparation method and application thereof, aiming at solving the problems of difficult injection and low gelling capacity of the water plugging profile control gel in the prior art.
According to the first aspect of the invention, the preparation method of the temperature response type gel plugging agent is provided, the hydroxybutyl chitosan is added into water, dissolved, heated and kept stand to obtain the temperature response type gel plugging agent; wherein the mass fraction of the hydroxybutyl chitosan is 0.05-0.8%, preferably 0.2-0.6%, more preferably 0.3-0.5%.
According to some embodiments of the present invention, a method for preparing a temperature-responsive gel blocking agent comprises the steps of:
step a), dispersing chitosan in an alkaline aqueous solution for alkalization treatment to obtain an alkalized chitosan aqueous solution;
the alkalization treatment is a pretreatment before the chitosan graft modification reaction, in order to fully swell and activate the chitosan, specifically, to activate the hydroxyl group of the chitosan so as to enable a subsequent nucleophilic reaction with butylene oxide.
Step b) adding the organic solution into the aqueous solution of the alkalized chitosan obtained in the step a), and stirring to obtain an organic solution of the alkalized chitosan;
and c) dropwise adding 1, 2-butylene oxide into the organic solution of the alkalized chitosan in the step b), heating for reaction, cooling, adjusting the pH value to be neutral, and drying to obtain the hydroxybutyl chitosan.
Further, the preparation of the temperature-responsive gel blocking agent further comprises: and d) adding the hydroxybutyl chitosan obtained in the step c) into water, dissolving, heating and standing to obtain the temperature response type gel plugging agent.
According to some embodiments of the invention, the amount of said chitosan used in step a) is from 5 to 15g; and/or the aqueous alkaline solution comprises an aqueous alkali metal solution, preferably an aqueous NaOH solution; the concentration of the aqueous NaOH solution is 30 to 70 wt%, preferably 30 to 60 wt%, and more preferably 30 to 50 wt%.
According to some embodiments of the invention, the chitosan in the step a) is dispersed in an alkaline aqueous solution for alkalization, stirred and filtered under the protection of nitrogen; the stirring time is 12-48 hours, and the stirring speed is 1500-5000 rpm.
Preferably, the step a) further comprises: after the alkalization treatment, filtration is carried out to obtain the alkalized chitosan.
According to some embodiments of the invention, the organic solution in step b) comprises an aqueous alcohol solution, preferably an aqueous isopropanol solution; the volume of the organic solution in the step b) is 20 to 100 percent of the aqueous solution of the alkalized chitosan, preferably 30 to 90 percent, and more preferably 40 to 80 percent; the concentration of the aqueous isopropanol solution is 10 to 40 wt%, preferably 15 to 35 wt%, more preferably 15 to 30 wt%; the stirring time is 18-48 hours, and the stirring speed is 1500-5000 rpm.
According to some embodiments of the invention, the molar ratio of the 1, 2-butylene oxide to the alkalized chitosan in step c) is from 20 to 50, preferably from 25 to 45, more preferably from 30 to 40:1; and/or in the step c), dropwise adding 1, 2-butylene oxide into the alkalized chitosan isopropanol solution in the step b), reacting for 1-8 hours at room temperature, and heating to react for 1-8 hours at the temperature of 80-120 ℃.
According to some embodiments of the present invention, in step c), the reaction solution obtained by the heating reaction is cooled to room temperature, an acidic solution is added dropwise to the cooled reaction solution, the pH is adjusted to be neutral, and then the mixture is filtered, centrifugally precipitated, and dried to obtain hydroxybutyl chitosan; preferably, the acidic solution comprises HCl solution, the concentration is 6-15%, and the dropping volume is 5-15 mL; preferably, the centrifugal precipitation rotating speed is 8000 rpm-15000 rpm, and the centrifugal time is 10-30 minutes.
According to some embodiments of the invention, the preparation method further comprises standing at a temperature of 70 to 140 ℃.
According to the second aspect of the invention, the temperature-responsive gel plugging agent prepared by the method comprises a hydroxybutyl chitosan aqueous solution; wherein the hydroxybutyl chitosan has a weight average molecular weight of 4 × 10 6 ～12×10 6 g/mol, preferably 6X 10 6 ～8×10 6 g/mol。
According to a third aspect of the present invention, there is also provided a method of preparing a temperature responsive gel plugging agent as described above or the use of a temperature responsive gel plugging agent as described above in the field of oilfield chemistry.
According to some embodiments of the invention, the method is used for deep profile control and water shutoff of an oil reservoir.
The invention has the beneficial effects that:
the temperature response type gel plugging agent for oil reservoir profile control water plugging provided by the invention is used for gelling by the hydrogen bond action in molecules and among molecules without adding any cross-linking agent, exists in a sol form at a common environmental temperature, is converted into gel when reaching a certain temperature, can be recovered into sol when the temperature is reduced again, and can be repeatedly converted between sol-gel-sol by repeating the heating-cooling process. The temperature response type thermal reversible phase transition gel provided by the invention can effectively utilize the temperature field change and distribution of an oil reservoir in the injection and production processes in the water shutoff profile control field, realize selective deep plugging, improve the problems of phase separation precipitation, difficult injection and poor gelling capability caused by the dilution and diffusion effects of the conventional gel plugging agent at present, and achieve the purpose of 'plugging without death', thereby avoiding technical risks such as oil well abandonment and the like.
Drawings
Fig. 1 is a reaction mechanism of chitosan modification according to an exemplary embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The temperature-sensitive thermo-reversible gel is synthesized and prepared through physical cross-linking (such as Van der Waals force or hydrogen bond action), the volume of the gel is not changed, phase transition (sol-gel-sol) is realized under certain conditions, the gel exists in a solution form at normal environmental temperature, and is converted into a gel state when reaching a certain temperature, and the process is reversible. The temperature-sensitive thermoreversible gel plugging and adjusting system has the technical characteristics that: 1. the temperature field change and distribution of the oil reservoir in the injection and production processes can be effectively utilized to realize selective plugging; 2. the particle type plugging agent and the resin type plugging agent can possibly have the risk of blocking a seepage passage and even causing scrapping of an oil well, and the temperature-sensitive heat-reversible gel can be used for effectively profile control and blocking without death, so that the temperature-sensitive heat-reversible gel blocking and adjusting system has no technical risk.
The chitosan is formed by connecting 2-aminoglucose and 2-acetylglucosamine through beta-1, 4 glycosidic bonds, is the only existing cationic aminopolysaccharide in the nature, has wide source, simple and easy preparation method and easy derivatization, and provides a basis for the application of the chitosan. The chitosan molecule crystal structure is very stable, so the chitosan molecule crystal structure is not dissolved in most solvents and only can be dissolved in an acid solution, the application of the chitosan molecule crystal structure is greatly limited, the chemical modification is carried out on the chitosan molecule, the water solubility of the chitosan can be improved, and various derivatives with different structures and different functions are formed. In recent years, a novel chitosan derivative, namely hydroxybutyl chitosan, has attracted attention, and a modified product is easily soluble in water, and an aqueous solution of the modified product is not subjected to the crosslinking action of a crosslinking agent, so that hydrogel with a network structure is formed through the mutual winding of high molecular chains of the hydroxybutyl chitosan and the hydrogen bonding action among the molecular chains.
The invention takes chitosan as a main agent, 1, 2-epoxybutane as an etherifying agent and isopropanol aqueous solution as a dispersion system to modify chitosan, obtains a modified water-soluble chitosan derivative, namely hydroxybutyl chitosan, and investigates factors influencing the gelling temperature and gelling time of hydroxybutyl chitosan hydrogel and the thermal reversible behavior thereof.
The following describes in detail a specific embodiment of the present invention with reference to specific examples.
Fig. 1 is a reaction mechanism of chitosan modification according to an exemplary embodiment of the present invention.
It should be noted that the reagents used in the examples of the present invention are all conventional products that are commercially available, and all of the reagents are analytically pure or chemically pure.
Example 1
1. Alkalization of chitosan: weighing 1g of chitosan (Haili biological products Co., ltd., chemical purity, CAS:9012-76-4, shandong, laizhou city) powder, dispersing in 20mL of NaOH (Beijing chemical reagent factory, chemical purity, CAS number: 1310-73-2) aqueous solution with the mass fraction of 30%, carrying out alkalization treatment, magnetically stirring at 1200rpm for 12h under the protection of N2, filtering and extruding redundant alkali liquor;
2. dispersing the alkalized chitosan: adding 4mL of 10% isopropanol (chemical purity, CAS number: 67-63-0) aqueous solution into the alkalized chitosan, magnetically stirring at 1500rpm for 18h, until the alkalized chitosan is completely dispersed in isopropanol system;
3. synthesis of hydroxybutyl chitosan: 1.92mL of 1, 2-epoxybutane (Beijing Bailingwei science and technology Co., ltd., analytical purity, CAS number: 106-88-7) is measured and added into the dispersion liquid of the alkalized chitosan dropwise, the stirring speed of the step 2 is kept, the reaction is carried out for 1h at room temperature, and the reaction is continued for 1h after the temperature is raised to 80 ℃;
4. purification of hydroxybutyl chitosan: after the reaction of the system is finished, the system is cooled to room temperature, 15mL of HCl (chemical purity, CAS number: 7647-01-0) solution with the mass fraction of 6% is added into the reaction liquid dropwise to adjust the pH value of the system to be neutral. Filtering out insoluble substances when the mixed solution becomes clear and transparent, precipitating with ethanol overnight, centrifuging at 8000rpm for 30min, collecting precipitate, and conventionally drying;
5. preparation of hydroxybutyl chitosan hydrogel: taking 0.03g of hydroxybutyl chitosan powder, adding into 30ml of deionized water, standing overnight at normal temperature until the hydroxybutyl chitosan powder is fully dissolved, heating to 70 ℃, and standing to form the gel.
The reaction mechanism of each step is shown in FIG. 1.
GPC measurement shows that the molecular weight of the hydroxybutyl chitosan prepared by the invention is 5.5 multiplied by 10 6 。
Example 2
1. Alkalizing chitosan: weighing 1.6g of chitosan powder, dispersing the chitosan powder in 20mL of NaOH aqueous solution with the mass fraction of 40% for alkalization, magnetically stirring the chitosan powder for 20 hours at the room temperature and the speed of 2500rpm under the protection of N2, filtering and extruding redundant alkali liquor;
2. dispersing the alkalized chitosan: adding 8mL of 18% by mass isopropanol aqueous solution into the alkalized chitosan, and magnetically stirring for 25 hours at 2500rpm until the alkalized chitosan is completely dispersed in an isopropanol system;
3. synthesis of hydroxybutyl chitosan: measuring 3.08mL of 1, 2-butylene oxide, dropwise adding into the dispersion of the alkalized chitosan, keeping the stirring speed of the step 2, reacting at room temperature for 3h, heating to 90 ℃, and continuing to react for 3h;
4. purifying hydroxybutyl chitosan: after the reaction of the system is finished, cooling to room temperature, and dropwise adding 12.5mL of HCl solution with the mass fraction of 8% into the reaction liquid to adjust the pH of the system to be neutral. After the mixed solution becomes clear and transparent, filtering out insoluble substances, precipitating with ethanol overnight, centrifuging at 9500rpm for 15min, collecting precipitate, and conventionally drying;
5. preparation of hydroxybutyl chitosan hydrogel: taking 0.075g of hydroxybutyl chitosan powder, adding into 30ml of deionized water, standing overnight at normal temperature until the hydroxybutyl chitosan powder is fully dissolved, heating to 90 ℃, and standing to form the gel.
Similarly to the above examples, the molecular weight of hydroxybutyl chitosan of the present invention was 4.3X 10 by GPC 6 。
Example 3
1. Alkalization of chitosan: weighing 2g of chitosan powder, dispersing the chitosan powder in 20mL of NaOH aqueous solution with the mass fraction of 50% for alkalization, magnetically stirring the chitosan powder for 30 hours at the room temperature and the speed of 3300rpm under the protection of N2, filtering and extruding redundant alkali liquor;
2. dispersing the alkalized chitosan: adding 12mL of 25% by mass isopropanol aqueous solution into the alkalized chitosan, and magnetically stirring for 33h at 3300rpm until the alkalized chitosan is completely dispersed in an isopropanol system;
3. synthesis of hydroxybutyl chitosan: measuring 4.48mL of 1, 2-butylene oxide, dropwise adding into the dispersion of the alkalized chitosan, keeping the stirring speed of the step 2, reacting at room temperature for 4.5h, heating to 100 ℃, and continuing to react for 4.5h;
4. purifying hydroxybutyl chitosan: after the reaction of the system is finished, cooling to room temperature, and dropwise adding 10mL of HCl solution with the mass fraction of 10.5% into the reaction liquid to adjust the pH value of the system to be neutral. Filtering out insoluble substances when the mixed solution becomes clear and transparent, precipitating with ethanol overnight, centrifuging at 11000rpm for 20min, collecting precipitate, and conventionally drying;
5. preparation of hydroxybutyl chitosan hydrogel: taking 0.12g hydroxybutyl chitosan powder, adding into 30ml deionized water, standing overnight at normal temperature until fully dissolved, heating to 110 ℃ and standing to form gel.
Similarly to the above examples, the molecular weight of hydroxybutyl chitosan prepared according to the present invention was 6.8X 10 by GPC 6 。
Example 4
1. Alkalizing chitosan: weighing 2.6g of chitosan powder, dispersing the chitosan powder in 20mL of NaOH aqueous solution with the mass fraction of 60%, carrying out alkalization treatment, magnetically stirring for 40h at the room temperature of 4200rpm under the protection of N2, filtering and extruding redundant alkali liquor;
2. dispersing the alkalized chitosan: adding 16mL of 32% by mass isopropanol aqueous solution into the alkalized chitosan, and magnetically stirring for 40h at 4200rpm until the alkalized chitosan is completely dispersed in an isopropanol system;
3. synthesis of hydroxybutyl chitosan: measuring 6.12mL of 1, 2-butylene oxide, dropwise adding into the dispersion liquid of the alkalized chitosan, keeping the stirring speed of the step 2, reacting at room temperature for 6h, heating to 110 ℃, and continuing to react for 6h;
4. purification of hydroxybutyl chitosan: after the reaction of the system is finished, cooling to room temperature, and dropwise adding 7.5mL of 12.5 mass percent HCl solution into the reaction liquid to adjust the pH value of the system to be neutral. Filtering out insoluble substances when the mixed solution becomes clear and transparent, precipitating with ethanol overnight, centrifuging at 13000rpm for 25min, collecting precipitate, and drying conventionally;
5. preparation of hydroxybutyl chitosan hydrogel: 0.165g of hydroxybutyl chitosan powder is taken and added into 30ml of deionized water, and the mixture is kept stand overnight at normal temperature until the mixture is fully dissolved, and then the mixture is heated to 125 ℃ and placed to form gel.
Similarly to the above examples, the molecular weight of hydroxybutyl chitosan of the present invention was measured by GPC and found to be 9.9X 10 6 。
Example 5
1. Alkalizing chitosan: weighing 3g of chitosan powder, dispersing the chitosan powder in 20mL of NaOH aqueous solution with the mass fraction of 70%, carrying out alkalization treatment, magnetically stirring at 5000rpm for 48h at room temperature under the protection of N2, filtering and extruding redundant alkali liquor;
2. dispersing the alkalized chitosan: adding 20mL of isopropanol aqueous solution with the mass fraction of 40% into the alkalized chitosan, and magnetically stirring for 48 hours at 5000rpm until the alkalized chitosan is completely dispersed in an isopropanol system;
3. synthesis of hydroxybutyl chitosan: measuring 8mL of 1, 2-butylene oxide, dropwise adding the 1, 2-butylene oxide into the dispersion liquid of the alkalized chitosan, keeping the stirring speed of the step 2, reacting at room temperature for 8 hours, and continuing to react for 8 hours after heating to 120 ℃;
4. purification of hydroxybutyl chitosan: after the reaction of the system is finished, cooling to room temperature, and dropwise adding 5mL of HCl solution with the mass fraction of 15% into the reaction liquid to adjust the pH of the system to be neutral. Filtering out insoluble substances when the mixed solution becomes clear and transparent, precipitating with ethanol overnight, centrifuging at 15000rpm for 30min, collecting precipitate, and conventionally drying;
5. preparation of hydroxybutyl chitosan hydrogel: taking 0.21g of hydroxybutyl chitosan powder, adding into 30ml of deionized water, standing overnight at normal temperature until the hydroxybutyl chitosan powder is fully dissolved, and heating to 140 ℃ for standing to form the gel.
Similarly to the above examples, the molecular weight of hydroxybutyl chitosan prepared according to the present invention was 11.5X 10 by GPC 6 。
[ Performance test ]
1. Viscosity test
The temperature responsive type gel plugging agent aqueous solution prepared in each example was prepared with normal temperature water at a certain mass fraction, stirred for 1 hour, left to stand for 1 hour to remove bubbles dissolved in the solution, and finally the viscosity was measured with a BROOKFIELD rotary viscometer model DV ii +, and the average of 3 measurements was taken as the viscosity value.
2. Determination of the gel point temperature
The temperature response type gel plugging agent aqueous solution prepared by the above embodiments with a certain volume and mass fraction is transferred into an ampoule bottle, the ampoule bottle is placed in an oven with a certain temperature, the ampoule bottle is taken out every 20min to observe the change of the solution, and when the solution becomes milky white gel, the temperature is recorded as the gel temperature.
3. Determination of plugging performance:
(1) Core preparation
Filling quartz sand according to formation sandstone, vacuumizing the filled core tube, setting the pressure to be-0.1 MPa, stabilizing for 0.5h, then measuring the actual porosity by using saturated water and the saturation time of 24h, and measuring the permeability of the core tube by using water. Core barrel model parameters: the lithology is quartz sand, the length is 60.00cm, the diameter is 2.5cm, and the interfacial agent is 4.91cm2.
(2) The temperature responsive gel blocking agent aqueous solution prepared in each example was injected
Under the condition of room temperature, injecting a certain mass fraction of the temperature response type gel plugging agent aqueous solution 1.5-2 PV prepared by the above embodiments into a simulated rock core pipe, then heating the device system to a certain temperature, and keeping the temperature for 3 hours.
(3) And (4) displacing by using hot water with the same temperature, recording the pressure difference at two ends of the core tube, and analyzing the plugging effect.
The gel point temperature of the temperature responsive gel blocking agent prepared in each of the above examples was evaluated by an indoor test, and the results are shown in table 1.
Table 1 viscosity and gel formation at different temperatures for the examples
Figure BDA0003121859670000091
In view of table 1, the temperature-responsive gel plugging agents prepared in examples 1 to 5 have a low viscosity at a temperature of less than 60 ℃ and are in a sol state, partially gel to form a milky filamentous gel when the temperature is increased to 65 ℃, and completely gel when the temperature is increased to 70 ℃. The system does not turn into gel at 70 deg.C, and gradually turns into gel with the temperature rise when the temperature is higher than 70 deg.C. Because one part of hydroxyl on the molecular chain of the hydroxybutyl chitosan is combined with water molecules and the other part of the hydroxyl forms hydrogen bond action in molecules and among molecules, the molecular chain is indirectly connected with the water molecules and separated from the water molecules, and meanwhile, the mobility of the molecular chain of the hydroxybutyl chitosan is reduced at lower temperature, so that the system can keep a sol state at lower temperature; when the temperature rises, the acting force of hydrogen bonds in molecules and among molecules is reduced, water molecules around the hydroxybutyl chitosan molecular chain are released, in addition, the mobility of the hydroxybutyl chitosan molecular chain is improved along with the rise of the temperature due to the rise of the temperature, the hydrophobic effect is improved, and the high molecular chains are mutually entangled, so that a three-dimensional reticular gel structure is formed.
The blocking performance of the temperature responsive gel blocking agents prepared in examples 1 to 5 was evaluated by an indoor test, and the results thereof are shown in table 2.
TABLE 2 blocking rate of the temperature responsive gel blocking agent prepared in each example at 80 deg.C
Raw permeability/mD Permeability/mD after plugging Plugging Rate/%
Example 1 1989.61 34.88 98.25
Example 2 1999.26 28.65 98.57
Example 3 2028.57 19.69 99.03
Example 4 1996.69 32.79 98.36
Example 5 2042.85 37.82 98.15
As can be seen from table 2, the plugging rate of the temperature-responsive gel plugging agent prepared in examples 1 to 5 can reach more than 98% at 80 ℃, which proves that the gel plugging agent has strong plugging strength and plugging capability and can meet the water plugging requirement of sandstone oil reservoirs.
What has been described above is merely a preferred example of the present invention. It should be noted that other equivalent variations and modifications can be made by those skilled in the art based on the technical teaching provided by the present invention, and the protection scope of the present invention should be considered.

Claims (11)

1. A preparation method of a temperature response type gel plugging agent is characterized in that hydroxybutyl chitosan is added into water, dissolved, heated and kept stand to obtain the temperature response type gel plugging agent;
wherein the mass fraction of the hydroxybutyl chitosan is 0.05-0.8%, preferably 0.2-0.6%, and more preferably 0.3-0.5%.
2. The method according to claim 1, wherein the hydroxybutyl chitosan is prepared by the method comprising the steps of:
step a), dispersing chitosan in an alkaline aqueous solution for alkalization treatment to obtain an alkalized chitosan aqueous solution;
step b) adding the organic solution into the aqueous solution of the alkalized chitosan obtained in the step a), and stirring to obtain an organic solution of the alkalized chitosan;
and c) dropwise adding 1, 2-butylene oxide into the organic solution of the alkalized chitosan in the step b), heating for reaction, cooling, adjusting the pH value to be neutral, and drying to obtain the hydroxybutyl chitosan.
3. The process according to claim 2, characterized in that the amount of chitosan used in step a) relative to the aqueous alkaline solution is from 5 to 15g; and/or
The alkaline aqueous solution comprises an aqueous alkali metal hydroxide solution, preferably an aqueous NaOH solution;
the concentration of the aqueous NaOH solution is 30 to 70% by weight, preferably 30 to 60% by weight, and more preferably 30 to 50% by weight.
4. The preparation method according to claim 2 or 3, wherein the step a) of dispersing the chitosan in the alkaline aqueous solution for alkalization treatment is performed under stirring and under the protection of nitrogen;
preferably, the stirring time is 12 to 48 hours, and the stirring speed is 1500rpm to 5000rpm;
preferably, the step a) further comprises: and filtering after alkalization treatment to obtain the alkalized chitosan.
5. The process according to any one of claims 2 to 4, wherein the organic solution in step b) comprises an aqueous solution of an alcohol, preferably an aqueous solution of isopropanol;
the volume of the organic solution in the step b) is 20 to 100 percent of the aqueous solution of the alkalized chitosan, preferably 30 to 90 percent, and more preferably 40 to 80 percent;
the concentration of the aqueous isopropanol solution is 10 to 40 wt%, preferably 15 to 35 wt%, more preferably 15 to 30 wt%;
the stirring time is 18-48 hours, and the stirring speed is 1500-5000 rpm.
6. The process according to any one of claims 2 to 5, wherein the molar ratio of 1, 2-butylene oxide to the alkalinized chitosan in step c) is from 20 to 50; and/or
In the step c), the 1, 2-butylene oxide is dripped into the alkalized chitosan isopropanol solution in the step b) to react for 1 to 8 hours at room temperature, and the heating reaction is carried out for 1 to 8 hours at the heating temperature of 80 to 120 ℃.
7. The preparation method according to any one of claims 2 to 6, wherein the reaction solution obtained by the heating reaction is cooled to room temperature in step c), an acidic solution is added dropwise to the cooled reaction solution, the pH is adjusted to be neutral, and then the mixture is filtered, centrifugally precipitated and dried to obtain hydroxybutyl chitosan;
preferably, the acidic solution comprises HCl solution, the concentration is 6-15%, and the dropping volume is 5-15 mL;
preferably, the centrifugal precipitation rotating speed is 8000-15000 rpm, and the centrifugation time is 10-30 minutes.
8. The production method according to any one of claims 1 to 7, characterized in that the standing is performed at a temperature of 70 to 140 ℃.
9. The temperature-responsive gel blocking agent prepared by the preparation method according to any one of claims 1 to 8, wherein the temperature-responsive gel blocking agent comprises an aqueous solution of hydroxybutyl chitosan;
wherein the hydroxybutyl chitosan has a weight average molecular weight of 4 × 10 6 ～12×10 6 g/mol, preferably 6X 10 6 ～8×10 6 g/mol。
10. Use of the preparation method according to any one of claims 1 to 8 or the temperature-responsive gel plugging agent according to claim 9 in the field of oilfield chemistry.
11. The use according to claim 10, characterized in that the use is in deep profile water plugging of oil reservoirs.
CN202110678564.0A 2021-06-18 2021-06-18 Temperature response type gel plugging agent and preparation method and application thereof Pending CN115490882A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116120642A (en) * 2023-02-13 2023-05-16 长江大学 Gel material and preparation method and application thereof

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116120642A (en) * 2023-02-13 2023-05-16 长江大学 Gel material and preparation method and application thereof

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