Adhesive response type supramolecular gel as well as preparation method and application thereof

Abstract

The invention discloses adhesion response type supramolecular gel as well as a preparation method and application thereof, and belongs to the technical field of agents for profile control and water shutoff of oil fields. The adhesion response type supramolecular gel is prepared from the following raw materials: 10 to 30 parts of acrylamide monomer; 0-20 parts of an acrylic monomer; 1-7 parts of an adhesion response type functional monomer; 0.01 to 0.5 part of a cross-linking agent; 0.01 to 1.0 part of an initiator; 0.1 to 1.0 part of a stabilizing agent; the adhesion response type functional monomer comprises an adhesion type functional monomer and a temperature-sensitive response type functional monomer in a molar ratio of (2-8): (1-3). The profile control agent has the effects of non-adhesion in near-well flow migration and efficient blocking of adhesion in deep fractures, and has an excellent fractured oil reservoir deep profile control effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of agents for profile control and water plugging in oil fields, and particularly relates to an adhesion-responsive supramolecular gel, a preparation method thereof, and an application thereof. Background Art

[0002] Disclosing the information of this background art section is only intended to increase the understanding of the overall background of the present invention, and it is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Conventional polymer gel profile control means are difficult to achieve effective plugging in old oil fields with serious water flooding and water channeling phenomena. Pre-crosslinked gel particles have a good effect on deep profile control in oil fields with strong heterogeneity, high water cut, and large pore channels. This is because the gel particles have a certain deformation ability after absorbing water and swelling, and can enter the deep formation by deforming and moving under a certain pressure difference. Then, as the formation pressure gradually decreases in the deep formation, the particles continuously absorb water and swell, can stay in the large pore channels and block the large pore channels, thereby adjusting the formation permeability and playing a role in deep fluid diversion. The preparation process of the gel particles is simple, and they have good stability during use, avoiding the disadvantages of poor gel formation effect and limited plugging effect of traditional gel plugging agents underground.

[0004] However, with the popularization and application of gel particles, some technical defects and application limitations have also emerged. For example, during on-site injection construction and the migration process in the deep and complex reservoir, the fully water-absorbed and swollen gel particles will be broken due to shear and extrusion, and the broken gel particles are easily washed out by the subsequent injected fluid, resulting in problems such as unstable plugging ability or poor effect when they are applied to deep fractures in the reservoir. Summary of the Invention

[0005] In order to solve the deficiencies of the prior art, the purpose of the present invention is to provide an adhesion-responsive supramolecular gel, a preparation method thereof, and an application thereof. After the particles made of this supramolecular gel enter the deep fractures, due to the thermosensitive response interfacial hydrophobicization effect generated by the increase in temperature, structural dynamic reversible recovery, adhesion between each other, and adhesion to the rock wall surface can be achieved, ensuring its high-strength plugging ability for deep fractures and achieving the effect of efficient exploitation of deep profile control in fractured reservoirs.

[0006] In order to achieve the above purpose, the technical solution of the present invention is as follows:

[0007] In the first aspect, an adhesion-responsive supramolecular gel, the preparation raw materials include the following components in parts by mass: 10 - 30 parts of acrylamide monomer; 0 - 20 parts of acrylic acid monomer; 1 - 7 parts of adhesion-responsive functional monomer; 0.01 - 0.5 parts of crosslinking agent; 0.01 - 1.0 parts of initiator; 0.1 - 1.0 parts of stabilizer;

[0008] The adhesion-responsive functional monomer includes an adhesion-type functional monomer and a thermosensitive-responsive functional monomer with a molar ratio of (2-8):(1-3). The adhesion-type functional monomer includes one or more of N-(3,4-dihydroxyphenethyl) methacrylamide (DMA), N-(3,4-dihydroxyphenylpropionic acid) methacrylamide (DMMA), and N-(methyl 3,4-dihydroxyphenylpropionate) methacrylamide (DMEMA); the thermosensitive-responsive functional monomer includes one or more of N-isopropylacrylamide (NIPAm) and N,N-dimethylaminoethyl methacrylate (DMAEMA).

[0009] Second, a method for preparing the above adhesion-responsive supramolecular gel includes the following steps:

[0010] In an inert atmosphere, acrylamide monomer, acrylic acid monomer, and adhesion-responsive functional monomer are sequentially added to the aqueous phase and mixed, and the pH value is adjusted to 5.0-8.5; then a crosslinking agent and a stabilizer are added and mixed evenly; then an initiator is added and mixed evenly to obtain an aqueous phase solution;

[0011] The aqueous phase solution is heated to initiate a polymerization reaction to obtain an adhesion-responsive supramolecular gel.

[0012] Third, the application of the above adhesion-responsive supramolecular gel in plugging deep fractures in oil reservoirs.

[0013] It includes: preparing the above adhesion-responsive supramolecular gel into particles, adding them to the injection fluid at a ratio of 500-3000 mg / L, and pumping them into the formation.

[0014] The beneficial effects of the present invention are as follows:

[0015] 1. The present invention introduces a thermosensitive-responsive functional monomer into the main chain of the internal structure of traditional polymer gel particles. Under the low-temperature conditions in the near-wellbore zone, the interface exhibits hydrophilic characteristics and a state of "hiding" the interfacial adhesion-type functional groups. When it enters the deep fractures and encounters high temperature, it produces a thermosensitive hydrophobicization effect, inducing the interface to transform into a hydrophobic characteristic and a state of "exposing" the interfacial adhesion-type functional groups. Thus, it produces the effects of non-adhesion during near-wellbore flow migration and efficient adhesion plugging in deep fractures, and has excellent deep profile control effects in fractured oil reservoirs. And the supramolecular gel particles contain the chemical agents required for crosslinking and adhesion, and are injected and transported in the formation only in the form of solid particles. All components are contained in the particles, avoiding the problems of non-gelation or poor gelation quality caused by dilution by formation water and shear degradation during the transport of conventional underground crosslinking systems in the formation. It improves the plugging ability for deep fractures.

[0016] 2. In the gel particle structure of the present invention, the adhesion-responsive functional monomer and the conventional polymerization monomers (acrylamide, acrylic acid) are on the same polymer molecular chain. When migrating in the formation porous medium, it can greatly reduce the problem of adsorption differences of different polymerization groups generated by multiple molecular chains, thereby enhancing the hydrogen bonding, π-π, hydrophobic association, cation-π and other adhesion supramolecular interactions in deep fractures, and enhancing the dynamic recovery and interfacial adhesion properties of the supramolecular gel particles. The adhesion-type functional monomer is located on the main chain of the internal structure of the traditional polymer gel particle, endowing the synthesized gel particles with the characteristics of dynamic recovery and adhesion to each other after shear fragmentation through hydrogen bonding, π-π, and hydrophobic association supramolecular interactions; in addition, the structure of the adhesion-type functional monomer can also generate hydrogen bonding, π-π, and cation-π supramolecular interactions with the rock wall surface in deep fractures, thereby endowing it with high-efficiency adhesion characteristics to the rock wall surface. The prepared gel particles have good shear resistance, strong self-healing ability, high adhesion strength, good plugging ability for deep fractures, and strong erosion resistance, and can be used as excellent deep plugging agents for fractured reservoirs.

[0017] 3. The adhesion-responsive supramolecular gel particles designed in the present invention can adjust their particle size and adhesion-responsive temperature according to reservoir conditions. The particle size is nanoscale, micron-scale or millimeter-scale, and the response temperature range is from 50°C to 200°C, with strong adaptability. The supramolecular gel particles can appropriately reduce the content of water-absorbing and swelling monomers (acrylamide monomer, acrylic acid monomer). Even if the gel particles cannot reach the plugging size after water absorption and swelling when entering the deep formation, they can still further aggregate and increase the size through the adhesion between particles, thereby weakening the particle fragmentation problem caused by shear while ensuring effective plugging of deep fractures. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0019] Figure 1 It is the macroscopic morphology of the adhesion-responsive supramolecular gel particles for deep plugging of fractured reservoirs prepared in Example 1 of the present invention.

[0020] Figure 2 It is the microscopic morphology of the supramolecular gel particles prepared in Example 1 of the present invention.

[0021] Figure 3 It is the interfacial adhesion effect (at room temperature) between the supramolecular gel particles prepared in Example 1 of the present invention does not occur.

[0022] Figure 4 It is the interfacial adhesion effect (at the temperature of deep reservoir) between the supramolecular gel particles prepared in Example 1 of the present invention.

[0023] Figure 5The interfacial adhesion effect between the supramolecular gel particles prepared in Example 1 of the present invention and a glass slide (simulating the rock wall surface) (within the deep reservoir temperature range). Detailed implementation manners

[0024] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further explanations for the present application. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0025] A typical implementation manner of the present invention provides an adhesion-responsive supramolecular gel, and the raw materials for preparation include the following components in parts by mass: 10-30 parts of acrylamide monomer; 0-20 parts of acrylic acid monomer; 1-7 parts of adhesion-responsive functional monomer; 0.01-0.5 part of crosslinking agent; 0.01-1.0 part of initiator; 0.1-1.0 part of stabilizer;

[0026] The adhesion-responsive functional monomer includes an adhesion-type functional monomer and a temperature-responsive functional monomer in a molar ratio of (2-8):(1-3). The adhesion-type functional monomer includes one or more of N-(3,4-dihydroxyphenethyl) methacrylamide (DMA), N-(3,4-dihydroxyphenylpropionic acid) methacrylamide (DMMA), and N-(methyl 3,4-dihydroxyphenylpropionate) methacrylamide (DMEMA); the temperature-responsive functional monomer includes one or more of N-isopropylacrylamide (NIPAm) and N,N-dimethylaminoethyl methacrylate (DMAEMA).

[0027] Among the above components, the adhesion-type functional monomer is introduced into the main chain of the internal structure of traditional polymer gel particles, endowing the synthesized gel particles with the characteristics of dynamic recovery and mutual adhesion after shear fragmentation through hydrogen bonding, π-π, and hydrophobic association supramolecular interactions; in addition, the structure of the adhesion-type functional monomer can also generate hydrogen bonding, π-π, and cation-π supramolecular interactions with the rock wall surface in deep fractures, thereby endowing it with high-efficiency adhesion characteristics to the rock wall surface; the temperature-responsive functional monomer is introduced into the main chain of the internal structure of traditional polymer gel particles. At low temperatures near the wellbore, the interface exhibits hydrophilic characteristics and "hides" the interfacial adhesion functional groups. After entering deep fractures, a temperature-responsive hydrophobization effect occurs at high temperatures, inducing the interface to transform into hydrophobic characteristics and "exposing" the interfacial adhesion functional groups. Furthermore, it produces the effect of non-adhesion during near-well flow migration and efficient plugging adhesion in deep fractures, and has excellent deep profile control effect for fractured reservoirs.

[0028] Optionally, the crosslinking agent includes one or more of N,N'-methylenebisacrylamide and ethylene glycol dimethacrylate; preferably N,N'-methylenebisacrylamide.

[0029] Optionally, the initiator includes one or more of ammonium persulfate and dimethyl 2,2'-azobis(2-methylpropionate).

[0030] Optionally, the stabilizer includes one or more of urea and disodium ethylenediaminetetraacetate.

[0031] Optionally, the aqueous phase includes one or more of deionized water and distilled water.

[0032] In a typical embodiment of the present invention, a method for preparing the above-mentioned adhesion-responsive supramolecular gel is provided, including: in an inert atmosphere, successively adding acrylamide monomer, acrylic acid monomer and adhesion-responsive functional monomer into the aqueous phase for mixing, and adjusting the pH to 5.0 - 8.5; then adding a crosslinking agent and a stabilizer and mixing evenly; then adding an initiator and mixing evenly to obtain an aqueous phase solution;

[0033] Performing heat-induced polymerization reaction on the aqueous phase solution to obtain the adhesion-responsive supramolecular gel.

[0034] Optionally, the inert atmosphere includes one or more of nitrogen and argon.

[0035] Optionally, in the aqueous phase solution, the mass ratio of the aqueous phase is 55% - 85%.

[0036] Optionally, the reagent used to adjust the pH includes one or more of sodium hydroxide, sodium carbonate and triethylamine.

[0037] Optionally, the method for initiating the polymerization reaction includes: heating to 30 - 60 °C and then holding for 0.5 - 4 h.

[0038] Optionally, it further includes the step of: crushing the adhesion-responsive supramolecular gel, drying it at 50 - 80 °C and then grinding, and screening out particles with a set particle size.

[0039] Optionally, drying until the gel mass is basically stable and unchanged, indicating that no further water loss can occur under this drying operation, and it becomes gel particles convenient for storage and transportation; specifically, weighing the mass at intervals of 1 - 2 h shows no change.

[0040] Optionally, the set particle size includes nano-scale, micro-scale and millimeter-scale particle sizes; different particle sizes can match different crack widths or reservoir conditions with different permeabilities. Nano-scale particle sizes are mainly for deep cracks generated after fracturing of low-permeability / tight reservoirs, and micro-scale and millimeter-scale particle sizes are mainly for deep cracks and large channels generated after fracturing of medium / high-permeability reservoirs.

[0041] In a typical embodiment of the present invention, an application of the above-mentioned adhesion-responsive supramolecular gel in plugging deep cracks in oil reservoirs is provided.

[0042] Including: adding the dried particles prepared from the above-mentioned adhesion-responsive supramolecular gel into the injection fluid at a ratio of 500 - 3000 mg / L, and pumping it into the formation.

[0043] Example 1

[0044] An adhesion-responsive supramolecular gel, the preparation raw materials of which include:

[0045] 17.82 g of acrylamide monomer; 4.9062 g of N-(3,4-dihydroxyphenethyl) methacrylamide (adhesion-type functional monomer) and 0.6328 g of N-isopropylacrylamide (thermosensitive-responsive functional monomer); 0.02056 g of N,N-methylenebisacrylamide (crosslinking agent); 0.285 g of ammonium persulfate (initiator), 0.06 g of urea (stabilizer); wherein, the adhesion-type functional monomer and the thermosensitive-responsive functional monomer are mixed together to form 5.5390 g of adhesion-responsive functional monomer.

[0046] The preparation method includes: in an inert atmosphere (nitrogen), respectively weighing acrylamide, N-(3,4-dihydroxyphenethyl) methacrylamide and N-isopropylacrylamide, and successively adding them into a beaker containing distilled water, stirring while adding until the solution becomes clear, and using a pH regulator to adjust the pH to 7.5; then adding N,N-methylenebisacrylamide into the solution in the beaker and stirring until it is completely dissolved; finally adding ammonium persulfate solution, and then stirring for 30 min and ultrasonically vibrating for 10 min (power 80 W) to remove the air in the solution, to prepare a uniformly dispersed aqueous solution with a water volume of 76.2754 g; placing the aqueous solution in a constant temperature water bath at 40 °C, taking it out after a polymerization reaction for 2 h; cutting the obtained gel into blocks, washing it 4 times with distilled water, placing it in a constant temperature drying oven at 60 °C and drying it until the mass does not change after weighing every 2 h (the drying time is 12 h), and then taking it out and grinding it with a planetary ball mill at 500 r / min for 4 h to prepare nano / micro-scale particles, thus obtaining the target adhesion-responsive supramolecular gel.

[0047] Example 2

[0048] An adhesion-responsive supramolecular gel, the preparation raw materials of which include:

[0049] 18.515 g of acrylamide monomer; 5.83 g of N-(3,4-dihydroxyphenethyl)methacrylamide (adhesive functional monomer) and 0.6328 g of N-isopropylacrylamide (thermosensitive responsive functional monomer); 0.02056 g of N,N-methylenebisacrylamide (crosslinking agent); 0.285 g of ammonium persulfate (initiator), 0.065 g of urea (stabilizer); among them, the adhesive functional monomer and the thermosensitive responsive functional monomer are mixed together to form 6.4628 g of adhesive-responsive functional monomer; the difference from Example 1 is that the dosages of acrylamide monomer and adhesive functional monomer are different.

[0050] The preparation method includes: in an inert atmosphere (nitrogen), weigh acrylamide, N-(3,4-dihydroxyphenethyl)methacrylamide and N-isopropylacrylamide respectively, and add them to a beaker containing distilled water in sequence, stirring while adding until the solution becomes clear, and using a pH regulator to adjust the pH to 7.5; then add N,N-methylenebisacrylamide to the solution in the beaker and stir until completely dissolved; finally, add ammonium persulfate solution, and then stir for 30 min, and ultrasonically vibrate for 10 min (power 80 W) to remove the air in the solution to prepare a uniformly dispersed aqueous solution with a water volume of 74.6516 g; place the aqueous solution in a constant temperature water bath at 55 °C, take it out after 2 h of polymerization reaction; cut the obtained gel into pieces, wash it 4 times with distilled water, place it in a constant temperature drying oven at 60 °C and dry it until the mass does not change after weighing every 2 h (the drying time is 12 h), and then take it out and grind it with a planetary ball mill at 500 r / min for 4 h, and screen out particles from nanoscale to millimeter scale to obtain the target adhesive-responsive supramolecular gel. The difference from Example 1 is that the polymerization reaction temperature is different.

[0051] Example 3

[0052] An adhesive-responsive supramolecular gel, the preparation raw materials include:

[0053] 17.82 g of acrylamide monomer; 6.13 g of N-(3,4-dihydroxyphenylpropionate)methacrylamide (DMEMA, adhesive functional monomer) and 0.6328 g of N-isopropylacrylamide (thermosensitive responsive functional monomer); 0.02056 g of N,N-methylenebisacrylamide (crosslinking agent); 0.285 g of ammonium persulfate (initiator), 0.063 g of urea (stabilizer); among them, the adhesive functional monomer and the thermosensitive responsive functional monomer are mixed together to form 6.7708 g of adhesive-responsive functional monomer; the difference from Example 1 is that the type and dosage of the adhesive functional monomer are different.

[0054] The preparation method includes: in an inert atmosphere (nitrogen), acrylamide, N-(3,4-dihydroxyphenylpropionic acid methyl ester) methacrylamide, and N-isopropylacrylamide are weighed separately and sequentially added to a beaker containing distilled water. Stir while adding until the solution becomes clear, and use a pH regulator to adjust the pH to 7.5; then add N,N'-methylenebisacrylamide to the solution in the beaker and stir until it is completely dissolved; finally, add ammonium persulfate solution, and then stir for 30 min. Ultrasonic oscillation for 10 min (power 80 W) is used to remove the air in the solution to prepare a uniformly dispersed aqueous solution with a water volume of 75.0486 g; the aqueous solution is placed in a constant temperature water bath at 60 °C, taken out after 2 h of polymerization reaction; the obtained gel is cut into pieces, washed 4 times with distilled water, placed in a constant temperature drying oven at 60 °C and dried until the mass does not change after weighing at intervals of 2 h (the drying time is 12 h), and then taken out and ground with a planetary ball mill at 500 r / min for 4 h, and particles ranging from nanometer to millimeter size are screened out to obtain the target adhesion-responsive supramolecular gel.

[0055] Example 4

[0056] An adhesion-responsive supramolecular gel, the preparation raw materials include:

[0057] 17.82 g of acrylamide monomer; 4.9062 g of N-(3,4-dihydroxyphenethyl) methacrylamide (adhesion-functional monomer) and 0.6328 g of N-isopropylacrylamide (temperature-responsive functional monomer); 0.12336 g of N,N'-methylenebisacrylamide (crosslinking agent); 0.285 g of ammonium persulfate (initiator), 0.06 g of urea (stabilizer); among them, the adhesion-functional monomer and the temperature-responsive functional monomer are mixed together to form 5.5390 g of adhesion-responsive functional monomer; the difference from Example 1 is the different dosage of the crosslinking agent.

[0058] The preparation method is the same as that of Example 1.

[0059] Example 5

[0060] An adhesion-responsive supramolecular gel, the preparation raw materials include:

[0061] 17.82 g of acrylamide monomer; 8.91 g of acrylic acid monomer; 4.9062 g of N-(3,4-dihydroxyphenethyl) methacrylamide (adhesion-functional monomer) and 0.6328 g of N-isopropylacrylamide (temperature-responsive functional monomer); 0.02056 g of N,N'-methylenebisacrylamide (crosslinking agent); 0.285 g of ammonium persulfate (initiator), 0.055 g of urea (stabilizer); among them, the adhesion-functional monomer and the temperature-responsive functional monomer are mixed together to form 5.5390 g of adhesion-responsive functional monomer; the difference from Example 1 is the addition of acrylic acid monomer.

[0062] The preparation method includes: in an inert atmosphere (nitrogen), weigh acrylamide, acrylic acid, N-(3,4-dihydroxyphenethyl) methacrylamide, and N-isopropylacrylamide respectively, and add them successively to a beaker containing distilled water. Stir while adding until the solution becomes clear, and use a pH regulator to adjust the pH to 8.0; then add N,N'-methylenebisacrylamide to the solution in the beaker and stir until it is completely dissolved; finally, add ammonium persulfate solution, then stir for 30 min, and ultrasonically vibrate for 10 min (power 80 W) to remove the air in the solution to prepare a uniformly dispersed aqueous solution with a water volume of 67.3704 g; place the aqueous solution in a constant temperature water bath at 50 °C, take it out after 2 h of polymerization reaction; cut the obtained gel into pieces, wash it 4 times with distilled water, place it in a constant temperature drying oven at 60 °C and dry it until the mass does not change after weighing at intervals of 2 h (the drying time is 12 h), then take it out and grind it with a planetary ball mill at 500 r / min for 4 h to prepare nano / micro-scale particles, that is, the target adhesion-responsive supramolecular gel; the difference from Example 1 is that the polymerization reaction temperature is different.

[0063] Example 6

[0064] An adhesion-responsive supramolecular gel, the preparation raw materials include:

[0065] 18.8013 g of acrylamide monomer; 5.1935 g of N-(3,4-dihydroxyphenethyl) methacrylamide (adhesion-type functional monomer) and 0.9263 g of N-isopropylacrylamide (temperature-responsive functional monomer); 0.02056 g of N,N'-methylenebisacrylamide (crosslinking agent); 0.285 g of dimethyl 2,2'-azobis(2-methylpropionate) (initiator); 0.07 g of urea (stabilizer); among them, the adhesion-type functional monomer and the temperature-responsive functional monomer are mixed together to form 6.1198 g of adhesion-responsive functional monomer; the difference from Example 1 is that acrylic acid monomer is added.

[0066] The preparation method includes: in an inert atmosphere (nitrogen), weigh acrylamide, N-(3,4-dihydroxyphenethyl) methacrylamide, and N-isopropylacrylamide respectively, and sequentially add them to a beaker containing distilled water. Stir while adding until the solution becomes clear, and use a pH regulator to adjust the pH to 7.0; then add N,N'-methylenebisacrylamide to the solution in the beaker and stir until it is completely dissolved; finally, add a solution of dimethyl 2,2'-azobis(2-methylpropionate), and then stir for 30 min and ultrasonically vibrate for 10 min (power 80 W) to remove the air in the solution, preparing a uniformly dispersed aqueous solution with a water volume of 74.7733 g; place the aqueous solution in a constant temperature water bath at 45 °C, take it out after 2 h of polymerization reaction; cut the obtained gel into pieces, wash it 4 times with distilled water, place it in a constant temperature drying oven at 60 °C and dry it until the mass does not change after weighing at intervals of 2 h (the drying time is 12 h), and then take it out and grind it for 4 h with a planetary ball mill at 500 r / min to prepare nano-scale particles, namely the target adhesion-responsive supramolecular gel; the difference from Example 1 is that the polymerization reaction temperature is different.

[0067] Example 7

[0068] An adhesion-responsive supramolecular gel, the preparation raw materials include:

[0069] 16.5225 g of acrylamide monomer; 3.426 g of N-(3,4-dihydroxyphenylpropionic acid) methacrylamide (adhesion-type functional monomer) and N,N-dimethylaminoethyl methacrylate (temperature-responsive functional monomer)

[0070] 2.0297 g; 0.02056 g of N,N'-methylenebisacrylamide (crosslinking agent); 0.285 g of dimethyl 2,2'-azobis(2-methylpropionate) (initiator), 0.01 g of disodium ethylenediaminetetraacetate (stabilizer); wherein, the adhesion-type functional monomer and the temperature-responsive functional monomer are jointly mixed to form 5.4557 g of adhesion-responsive functional monomer; the difference from Example 1 is that the types of the temperature-responsive functional monomer and the initiator are different.

[0071] The preparation method includes: in an inert atmosphere (nitrogen), weigh acrylamide, N-(3,4-dihydroxyphenethyl) methacrylamide, and N-isopropylacrylamide respectively, and add them successively to a beaker containing distilled water. Stir while adding until the solution becomes clear, and use a pH regulator to adjust the pH to 7.5; then add N,N'-methylenebisacrylamide to the solution in the beaker and stir until it is completely dissolved; finally, add a solution of dimethyl 2,2'-azobis(2-methylpropionate), then stir for 30 min, and ultrasonically vibrate for 10 min (power 80 W) to remove the air in the solution, thus preparing a uniformly dispersed aqueous solution with a water volume of 77.7062 g; place the aqueous solution in a constant temperature water bath at 40 °C, take it out after a polymerization reaction for 2 h; cut the obtained gel into pieces, wash it 4 times with distilled water, place it in a constant temperature drying oven at 50 °C and dry it until the mass does not change when weighed at intervals of 2 h (the drying time is 12 h), then take it out and grind it with a planetary ball mill at 500 r / min for 4 h to prepare nano- and micro-scale particles, thus obtaining the target adhesion-responsive supramolecular gel.

[0072] Comparative Example 1

[0073] A conventional gel particle profile control agent for deep plugging of fractured reservoirs, and the preparation raw materials include:

[0074] 23.359 g of acrylamide monomer; 0.069 g of N,N'-methylenebisacrylamide (crosslinking agent); 0.285 g of ammonium persulfate (initiator), and 0.06 g of urea (stabilizer).

[0075] The preparation method includes: in an inert atmosphere (nitrogen), weigh acrylamide and add it to a beaker containing distilled water. Stir while adding until the solution becomes clear; then add N,N'-methylenebisacrylamide to the solution in the beaker and stir until it is completely dissolved; finally, add a solution of ammonium persulfate, then stir for 30 min, and ultrasonically vibrate for 10 min (power 80 W) to remove the air in the solution, thus preparing a uniformly dispersed aqueous solution with a water volume of 76.227 g; place the aqueous solution in a constant temperature water bath at 50 °C, take it out after a polymerization reaction for 2 h; cut the obtained gel into pieces, wash it 4 times with distilled water, place it in a constant temperature drying oven at 50 °C and dry it until the mass does not change when weighed at intervals of 2 h (the drying time is 12 h), then take it out and grind it with a planetary ball mill at 500 r / min for 4 h, and screen out particles from nano-scale to millimeter-scale, thus obtaining the conventional gel particle profile control agent.

[0076] Performance test

[0077] The adhesion-responsive supramolecular gel obtained in Example 1 is as Figure 1 shown, and its appearance is white powder; its particle size is as Figure 2As shown, it is dispersive, indicating a significant size difference, with an average particle size of 400 nm. It will undergo a water absorption and swelling effect in the formation water of a certain oilfield (salinity 10111.6 mg / L) and at room temperature (25°C), but there is no mutual adhesion between the particles ( Figure 3 ); however, if it is placed in the formation water of a certain oilfield (salinity 10111.6 mg / L) and the deep reservoir temperature (60°C) environment for a period of time, a water absorption and swelling effect and an inter-particle adhesion interaction will occur. As Figure 4 shown, it has a certain tensile strength; after staining the gel in Figure 4 with a blue staining agent, it is found that the swollen gel particles will produce an adhesion interaction, and there will also be a strong adhesion interaction with the glass slide surface (simulating the rock wall surface). As Figure 5 shown, it indicates that after it is injected into the deep formation, under the action of temperature response, it can produce a strong adhesion and plugging effect with the rock wall surface, and has excellent tensile strength and erosion resistance. The above test results show that the adhesion-responsive supramolecular gel particles show hydrophilic characteristics and "hidden" interfacial adhesion functional groups at low temperature in the near-wellbore area, and the temperature-sensitive hydrophobicization effect occurs at high temperature, and the interface changes to hydrophobic characteristics and "exposed" interfacial adhesion functional groups. It has the effect of non-adhesion during near-wellbore flow migration and efficient adhesion and plugging in the formation fractures.

[0078] The plugging performance of the adhesion-responsive supramolecular gels prepared in Examples 1 to 3 and Example 6 and the conventional gel particle profile control agent prepared in Comparative Example 1 was tested. The test process included: using a fractured core with a specification of Φ2.5 cm × 2.5 cm × 10 cm, and injecting the formation water gel particles at a uniform flow rate of 0.2 mL·min -1 respectively using the original heterogeneous matrix core and the fractured core with gaskets. After the injection of the gel particles into the core was completed, the core holder was placed in an oven at 60°C for 24 h to allow the gel particles to fully swell in the core, and then subsequent water flooding was carried out to calculate the permeability of the core after plugging with the adhesion-responsive supramolecular gel particles; the plugging effect is shown in Table 1.

[0079] Table 1

[0080]

[0081] It can be seen that the adhesion-responsive supramolecular gel shows a more excellent plugging efficiency (higher plugging rate) than the conventional gel particle profile control agent. This is because in the deep reservoir temperature environment, the supramolecular gel particles can be dynamically restored through various supramolecular interactions after migration and fragmentation, and the inter-particle adhesion is stronger and it can adhere to the rock wall surface, thus achieving efficient plugging of the fractured core.

[0082] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An adhesion-responsive supramolecular gel, characterized in that: The raw materials for preparation include the following components in parts by weight: 10 to 30 parts of acrylamide monomer; 0 to 20 parts of acrylic acid monomer; 1 to 7 parts of adhesion responsive functional monomer; 0.01 to 0.5 parts of crosslinking agent; 0.01 to 1.0 parts of initiator; 0.1 to 1.0 parts of stabilizer; The adhesion-responsive functional monomer includes an adhesion-responsive functional monomer and a temperature-sensitive responsive functional monomer in a molar ratio of (2-8):(1-3), wherein the adhesion-responsive functional monomer includes one or more of N-(3,4-dihydroxyphenylethyl)methacrylamide, N-(3,4-dihydroxyphenylpropionic acid)methacrylamide and N-(3,4-dihydroxyphenylpropionic acid methyl ester)methacrylamide; and the temperature-sensitive responsive functional monomer includes one or more of N-isopropylacrylamide and N,N-dimethylaminoethyl methacrylate.

2. The adhesion-responsive supramolecular gel according to claim 1, characterized in that: The crosslinking agent includes one or more of N,N-methylenebisacrylamide and ethylene glycol dimethacrylate; preferably N,N-methylenebisacrylamide.

3. The adhesion-responsive supramolecular gel according to claim 1, characterized in that: The initiator includes one or more of ammonium persulfate and dimethyl azobisisobutyrate; Alternatively, the stabilizer comprises one or more of urea and disodium ethylenediaminetetraacetic acid.

4. A method for preparing an adhesion-responsive supramolecular gel according to any one of claims 1 to 3, characterized in that: include: In an inert atmosphere, acrylamide monomer, acrylic acid monomer and adhesion responsive functional monomer are sequentially added to the aqueous phase and mixed, and the pH is adjusted to 5.0-8.5; then a crosslinking agent and a stabilizer are added and mixed evenly; then an initiator is added and mixed evenly to obtain an aqueous phase solution; The aqueous solution is heated to initiate a polymerization reaction to obtain an adhesion-responsive supramolecular gel.

5. The preparation method according to claim 4, characterized in that: The inert atmosphere includes one or more of nitrogen and argon; Alternatively, the aqueous phase includes one or more of deionized water and distilled water.

6. The preparation method according to claim 4, characterized in that: The reagent used to adjust the pH includes one or more of sodium hydroxide, sodium carbonate and triethylamine.

7. The preparation method according to claim 4, characterized in that: The method also includes the steps of crushing the adhesion-responsive supramolecular gel, drying it at 50-80° C., grinding it, and sieving out particles with a set particle size.

8. The preparation method according to claim 7, characterized in that: The set particle size includes nanometer, micrometer and millimeter particle sizes.

9. Use of the adhesion-responsive supramolecular gel according to any one of claims 1 to 3 in plugging deep fractures in oil reservoirs.

10. The use according to claim 9, characterized in that The dry particles prepared from the adhesion-responsive supramolecular gel are added into the injection fluid at a ratio of 500 to 3000 mg / L and pumped into the formation.

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