CO2 induced reaction type tackifying poly-surfactant as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of CO2 oil displacement and burying in the oil reservoir development technology, and discloses a CO2 induced reaction type tackifying poly-surfactant and a preparation method and application thereof, the CO2 induced reaction type tackifying poly-surfactant has a structure as shown in formula (1), x: y: z = 100: (30-150): (1-5); m is 1-7, n is 5-20, and R is selected from at least one of formulas (2) to (7); when CO2 is injected, the CO2-induced reactive tackifying poly-surfactant can induce hydroxyl and aldehyde groups of the CO2-induced reactive tackifying poly-surfactant to be subjected to a coupling reaction to generate gel, so that tackifying is achieved, and the channeling sealing effect is achieved; # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the technical field of CO2 oil displacement and storage in oil reservoir development technology, and specifically relates to a CO2 induced reaction type viscosity increasing polymer surface agent and a preparation method and application thereof. Background Art

[0002] CO2 injection is a simple and effective way to supplement energy in offshore heavy oil reservoirs. Due to its large diffusion coefficient and strong solubility, CO2 can quickly penetrate into the heavy oil, greatly reducing the viscosity of the heavy oil and improving the development efficiency of offshore heavy oil reservoirs. In addition, while CO2 can improve crude oil recovery, it can also achieve geological storage of CO2 in offshore heavy oil reservoirs.

[0003] At present, offshore heavy oil CO2 flooding and storage face the following challenges:

[0004] (1) Offshore heavy oil reservoirs are mostly loose sandstone reservoirs, which have the characteristics of loose rock cementation, high reservoir permeability, and severe heterogeneity. At the same time, due to the large difference in the CO2 / heavy oil mobility ratio, CO2 injection will inevitably flow, resulting in poor energy replenishment and low degree of sweep.

[0005] (2) Controlling gas cross-talk is the key to improving the efficiency of CO2 flooding and storage, and the flooding agent is the core. However, due to the strong acidity of CO2 after dissolving in water and the high intensity of gas injection, conventional flooding agents "cannot withstand and control for long".

[0006] Therefore, it is necessary to find a suitable method to block gas and control channeling to improve the CO2 flooding effect. At present, the inorganic control system mainly includes ultrafine cement, stabilized sodium soil, fly ash and other particle systems, which are acid-resistant, high-temperature and high-salt-resistant and low-cost. However, due to its composition of inorganic rigid particles and high density, it cannot deform and migrate in complex pore throat structures, and it is difficult to migrate deep in the reservoir. It is mostly retained in the near-wellbore area, resulting in a small plugging radius and unsatisfactory reservoir control effect. The organic control system mainly includes polymer microspheres, gel dispersions, pre-crosslinked particles, etc., which have the common characteristics of flexibility and easy deformation. The above three organic particle control systems have been successfully applied in the control of water channeling / nitrogen injection channeling. However, it is not ideal in the control of CO2 gas channeling, and its CO2 resistance is insufficient.

[0007] CO2-responsive materials have become a hot topic in the field of gas channeling control because their characteristics can change with the environment and space. Among them, the most mature research is CO2-responsive viscosity-increasing surfactants such as amino, amidine, guanidine and nitrogen-containing azole heterocyclics. The responsive surfactants undergo protonation reaction with CO2, counterion electrostatic shielding and self-assembly effect, and the aggregation morphology of the surfactants changes from spherical to worm-like micelles. The worm-like micelles entangle with each other to form a highly viscoelastic three-dimensional network structure, which can achieve the blocking and regulation of gas channeling channels, thereby expanding the CO2 swept volume and oil recovery efficiency. The surfactant aqueous solution has low viscosity and is easy to inject during the injection stage, which effectively solves the difficulty of injecting conventional adjustment and displacement agents. There is basically no problem in the control of CO2 gas channeling in dense, ultra-low permeability or low permeability oil and gas reservoirs. However, for offshore heavy oil reservoirs, the reservoirs are more highly porous, permeable and heterogeneous, and the surfactants also have channeling problems, which have limitations in the control of CO2 gas channeling. In addition, the formation of worm-like micelles requires a high concentration of surfactant, that is, the surfactant concentration in the injection stage is much higher than the concentration used in conventional surfactant flooding, which increases the cost of gas channeling control. Therefore, reducing the cost of CO2-responsive surfactant working fluid and solving the problem of "uncontrollable" under more severe conditions of high porosity, high permeability and heterogeneity in reservoirs are the key to its application in offshore CO2 flooding and storage.

[0008] Therefore, in view of the particularity of offshore heavy oil CO2 flooding and storage environment, there is an urgent need for a plugging agent with the characteristics of acid corrosion resistance, good injectability and high gel strength to deal with possible CO2 gas leakage problems. Summary of the invention

[0009] The purpose of the present invention is to overcome the problem of conventional flooding agents in the prior art that they are "not durable and cannot be controlled for a long time", and to provide a CO2-induced reaction-type viscosity-increasing polymer surface agent and its preparation method and application. When CO2 is injected, the CO2-induced reaction-type viscosity-increasing polymer surface agent can induce a coupling reaction between its hydroxyl and aldehyde groups to generate a gel to increase viscosity and achieve the effect of blocking channeling. It has low initial viscosity, strong fluidity, and good injectability. After cross-linking, it has good chemical stability and can achieve long-term effective blocking.

[0010] In order to achieve the above-mentioned object, the present invention provides a CO2-induced reactive viscosity-enhancing polymer surface agent, wherein the CO2-induced reactive viscosity-enhancing polymer surface agent has a structure shown in formula (1);

[0011]

[0012] Wherein, R is selected from at least one of formula (2) to formula (7):

[0013]

[0014]

[0015] x:y:z=100: (30-150): (1-5);

[0016] m is 1-7, n is 5-20.

[0017] The second aspect of the present invention provides a method for preparing a CO2-induced reactive viscosity-increasing polymerizing agent, wherein the preparation method comprises:

[0018] (S1) in the presence of an initiator, a polyhydroxy monomer containing a terminal double bond represented by formula (8), an aldehyde monomer containing a terminal double bond represented by formula (9), a hydrophobic long-chain acrylate represented by formula (10) and a solvent are contacted to react;

[0019]

[0020] Wherein, R is selected from at least one of formula (2) to formula (7):

[0021]

[0022]

[0023] Wherein, m is 1-7;

[0024]

[0025] Wherein, n is 5-20;

[0026] (S2) The product obtained in step (S1) is precipitated in methanol to obtain a CO2-induced reactive thickening polymerizing agent.

[0027] The third aspect of the present invention provides a CO2 induced reaction type viscosity enhancing and polymerizing agent prepared by the aforementioned preparation method.

[0028] A fourth aspect of the present invention provides an application of the aforementioned CO2 induced reaction type viscosity increasing polymerizing agent as a gas channeling preventing plugging agent in CO2 oil recovery.

[0029] Through the above technical scheme, the CO2-induced reactive viscosity-increasing polymer surface agent of the present invention can induce the hydroxyl and aldehyde groups to undergo coupling reaction when CO2 is injected, generating gel to increase viscosity and achieve the effect of blocking channeling. It has low initial viscosity, strong fluidity, and good injectability. After cross-linking, it has good chemical stability and can achieve long-term effective blocking. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the viscosity of an aqueous solution containing the CO2-induced reaction-type viscosity-increasing polymerizing agent prepared in Example 2 of the present invention at a concentration of 2 wt % under different CO2-introduced time periods;

[0031] Figure 2 The graph shows the storage modulus and loss modulus of the gel generated by the coupling reaction between an aqueous solution containing the CO2-induced reactive thickening polymer prepared in Example 2 of the present invention at a concentration of 2 wt% and CO2. DETAILED DESCRIPTION

[0032] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0033] As mentioned above, the first aspect of the present invention provides a CO2-induced reactive viscosity-enhancing polymer surface agent, wherein the CO2-induced reactive viscosity-enhancing polymer surface agent has a structure shown in formula (1);

[0034]

[0035] Wherein, R is selected from at least one of formula (2) to formula (7):

[0036]

[0037]

[0038] x:y:z=100: (30-150): (1-5);

[0039] m is 1-7, n is 5-20.

[0040] According to the present invention, preferably, x:y:z=100:(30-150):(2-5).

[0041] According to the present invention, preferably, m is 5-7; preferably, m is 5-6; more preferably, m is 5.

[0042] According to the present invention, preferably, n is 8-18; preferably, n is 15-17; more preferably, n is 16-17; further preferably, n is 17.

[0043] According to the present invention, the viscosity-average molecular weight of the CO2-induced reactive viscosity-increasing polymer is 20,000-85,000 g / mol, preferably 30,000-65,000 g / mol, and more preferably 30,145-64,700 g / mol.

[0044] The second aspect of the present invention provides a method for preparing a CO2-induced reactive viscosity-increasing polymerizing agent, wherein the preparation method comprises:

[0045] (S1) in the presence of an initiator, a polyhydroxy monomer containing a terminal double bond represented by formula (8), an aldehyde monomer containing a terminal double bond represented by formula (9), a hydrophobic long-chain acrylate represented by formula (10) and a solvent are contacted to react;

[0046]

[0047] Wherein, R is selected from at least one of formula (2) to formula (7):

[0048]

[0049] Wherein, m is 1-7;

[0050]

[0051] Wherein, n is 5-20;

[0052] (S2) The product obtained in step (S1) is precipitated in methanol to obtain a CO2-induced reactive thickening polymerizing agent.

[0053] In the present invention, it should be noted that R, m and n are consistent with those described above and will not be repeated here.

[0054] The inventors of the present invention have found that the present invention uses a polyhydroxy monomer containing a terminal double bond, an aldehyde monomer containing a terminal double bond and a hydrophobic long-chain acrylate as raw materials, and prepares a CO2-induced reactive viscosity-increasing polymer surface agent through a free radical polymerization reaction. When CO2 is injected, the CO2-induced reactive viscosity-increasing polymer surface agent can induce a coupling reaction between its hydroxyl group and the aldehyde group to generate a gel to increase viscosity and achieve the effect of blocking channeling. It has low initial viscosity, strong fluidity and good injectability. After cross-linking, it has good chemical stability and can achieve long-term effective blocking.

[0055] The anti-channeling principle is achieved through the following reactions:

[0056]

[0057]

[0058] According to the present invention, the molar ratio of the polyhydroxy monomer containing terminal double bonds shown in formula (8), the aldehyde monomer containing terminal double bonds shown in formula (9), and the hydrophobic long-chain acrylate shown in formula (10) is 100:(30-150):(1-5), preferably 100:(50-100):(3-5).

[0059] According to the present invention, preferably, the polyhydroxy monomer containing a terminal double bond, the aldehyde monomer containing a terminal double bond, and the initiator can be dissolved in solvent water first, and then the hydrophobic long-chain acrylate is added after reacting for 10-30 minutes.

[0060] According to the present invention, the initiator is selected from at least one of ammonium persulfate, potassium persulfate, azobisisopropylimidazoline hydrochloride and azobisisobutylamidine hydrochloride.

[0061] According to the present invention, the solvent is water.

[0062] According to the present invention, based on the total amount A of the polyhydroxy monomer containing a terminal double bond shown in formula (8), the aldehyde monomer containing a terminal double bond shown in formula (9), and the hydrophobic long-chain acrylate shown in formula (10), the amount of the initiator is 0.1-2wt%A, preferably 0.1-1wt%A, and the amount of the solvent is 10-30A.

[0063] In the present invention, the polyhydroxy monomer containing terminal double bonds represented by formula (8) can play a role in undergoing aldol condensation with aldehyde groups and provide hydrophilicity.

[0064] In the present invention, the aldehyde monomer containing a terminal double bond represented by formula (9) can play a role in aldol condensation with a hydroxyl group.

[0065] In the present invention, the hydrophobic long-chain acrylate represented by formula (10) can provide lipophilicity and realize the function of surface activity, and the surfactant needs to have a hydrophobic monomer to provide lipophilic and hydrophobic effects.

[0066] According to the present invention, the reaction conditions include: under N2 atmosphere, the temperature is 50-80°C, and the time is 2-12h; preferably, the temperature is 60-70°C, and the time is 5-6h.

[0067] The second aspect of the present invention provides a CO2-induced reaction-type viscosity-enhancing polymerizing agent prepared by the aforementioned preparation method.

[0068] The third aspect of the present invention provides an application of the aforementioned CO2 induced reaction type viscosity increasing polymerizing agent as a gas channeling preventing plugging agent in CO2 oil recovery.

[0069] According to the present invention, the CO2-induced reactive thickening polymer surfactant is prepared into an aqueous solution with a concentration of 0.5-2wt%; preferably, at 25°C, the viscosity of the 2wt% polymer surfactant solution is 10-70mPa·s, preferably 15-45mPa·s, and more preferably 19.7-41.2mPa·s.

[0070] According to the present invention, at 25°C, when CO2 is injected, the viscosity of the gel generated by the 2 wt% polymer surfactant solution is 9000-26000 mPa·s, preferably 9050-26000 mPa·s, and more preferably 9056-23425 mPa·s.

[0071] According to a particularly preferred embodiment of the present invention, a method for preparing a CO2-induced reactive viscosity-enhancing polymerizing agent is characterized in that it comprises the following steps:

[0072] (S1) dissolving a polyhydroxy monomer containing a terminal double bond, an aldehyde monomer containing a terminal double bond, and an initiator in a water solvent, heating to 60-70° C. under a nitrogen atmosphere, reacting for 10 minutes, adding a hydrophobic long-chain acrylate, and continuing the reaction for 5-6 hours to obtain a reaction solution;

[0073] (S2) The reaction solution obtained in step (S1) is precipitated in methanol to obtain a CO2-induced reactive thickening polymerizing agent.

[0074] The structural formulas of the polyhydroxy monomer with a terminal double bond, the aldehyde monomer with a terminal double bond and the hydrophobic long-chain acrylate are consistent with those described above and will not be described in detail here.

[0075] The present invention will be described in detail below through examples.

[0076] In the following examples and comparative examples:

[0077] The viscosity parameters were measured by the rotational viscometer method;

[0078] The molecular weight parameters were measured by the intrinsic viscosity method;

[0079] The raw materials N-acryloyl(trishydroxymethyl)aminomethane and octadecyl acrylate were commercially available from Adamas.

[0080] Example 1

[0081] This embodiment is intended to illustrate the CO2-induced reaction-type viscosity-increasing polymerizing agent prepared by the method of the present invention.

[0082] (S1) Add 17.5 g (i.e., 0.1 mol) of N-acryloyl (trimethylol) aminomethane, 10.45 g (i.e., 0.03 mol) of The monomer and 0.28g potassium persulfate initiator were added with 280mL deionized water solvent; N2 was bubbled for 20 minutes, the temperature was raised to 60°C, and the mixture was stirred for 10 minutes. Then 1.62g (i.e., 0.005mol) of octadecyl acrylate monomer was added to the reaction flask with a syringe, and the reaction was continued for 5 hours;

[0083] (S2) pouring the product (polymer product solution) obtained after step (S1) into methanol to precipitate the solid, which is the CO2-induced reactive thickening polymer surface agent.

[0084] In addition, the CO2-induced reactive type viscosity-increasing polymerizing agent has the following structure:

[0085]

[0086] Among them, x:y:z=100:30:5;

[0087] m is 5 and n is 17.

[0088] The viscosity average molecular weight of the CO2-induced reactive viscosity-increasing polymer is 35860 g / mol.

[0089] Example 2

[0090] This embodiment is intended to illustrate the CO2-induced reaction-type viscosity-increasing polymerizing agent prepared by the method of the present invention.

[0091] (S1) Add 8.75 g (i.e., 0.05 mol) of N-acryloyl (trimethylol) aminomethane, 17.4 g (i.e., 0.05 mol) of The monomer and 0.27g ammonium persulfate initiator were added with 268.5mL deionized water solvent. After N2 bubbling for 20 minutes, the temperature was raised to 65°C and stirred for 10 minutes. Then 0.486g (i.e., 0.0015mol) of octadecyl acrylate monomer was added to the reaction flask with a syringe and the reaction was continued for 6 hours;

[0092] (S2) pouring the product (polymer product solution) obtained after step (S1) into methanol to precipitate the solid, which is the CO2-induced reactive thickening polymer surface agent.

[0093] In addition, the CO2-induced reactive type viscosity-increasing polymerizing agent has the following structure:

[0094]

[0095] Among them, x:y:z=100:100:3;

[0096] m is 5 and n is 17.

[0097] The viscosity average molecular weight of the CO2-induced reactive viscosity-increasing polymer is 42500 g / mol.

[0098] in addition, Figure 1 Schematic diagram of the viscosity of a 2 wt % aqueous solution containing the CO 2 induced reaction type viscosity enhancing agent prepared in Example 2 of the present invention at different CO 2 introduction times; Figure 1It can be seen that when CO2 is introduced into an aqueous solution with a concentration of 2wt% containing the CO2-induced reactive thickening and polymerizing agent prepared in Example 2 of the present invention, the viscosity of the solution increases to 500-580mPa·s after one day (1Day), the viscosity increases to 8300-9200mPa·s after three days (3Days), and the viscosity increases to 16000-22000mPa·s after five days (5Days).

[0099] Figure 2 The graph is a storage modulus and loss modulus graph of a gel generated by a coupling reaction between an aqueous solution containing the CO2-induced reactive thickening agent prepared in Example 2 of the present invention at a concentration of 2 wt% and CO2; wherein the abscissa represents the angular frequency, the curve G′ represents the storage modulus, and G″ represents the loss modulus. The storage modulus being greater than the loss modulus indicates that a gel has been formed. And the strength of the gel is about 22 Pa.

[0100] Example 3

[0101] This embodiment is intended to illustrate the CO2-induced reaction-type viscosity-increasing polymerizing agent prepared by the method of the present invention.

[0102] (S1) Add 8.75 g (i.e., 0.05 mol) of N-acryloyl (trimethylol) aminomethane, 26.25 g (i.e., 0.075 mol) of The monomer and 0.35g of azodiisopropylimidazoline hydrochloride (AIBI) initiator were added with 353.5mL of deionized water solvent. After N2 bubbling for 20 minutes, the temperature was raised to 70°C and stirred for 10 minutes. Then 0.35g (i.e., 0.001mol) of octadecyl acrylate monomer was added to the reaction flask with a syringe and the reaction was continued for 5.5 hours;

[0103] (S2) pouring the product (polymer product solution) obtained after step (S1) into methanol to precipitate the solid, which is the CO2-induced reactive thickening polymer surface agent.

[0104] In addition, the CO2-induced reactive type viscosity-increasing polymerizing agent has the following structure:

[0105]

[0106] Among them, x:y:z=100:150:2;

[0107] m is 5 and n is 17.

[0108] The viscosity average molecular weight of the CO2-induced reactive viscosity enhancing polymer is 64700 g / mol.

[0109] Example 4

[0110] This embodiment is intended to illustrate the CO2-induced reaction-type viscosity-increasing polymerizing agent prepared by the method of the present invention.

[0111] (S1) Add 1.75 g (i.e., 0.01 mol) of N-acryloyl (trishydroxymethyl) aminomethane, 5.25 g (i.e., 0.015 mol) of The monomer and 0.07g of azodiisopropylimidazoline hydrochloride (AIBI) initiator were added with 70mL of deionized water solvent. After N2 bubbling for 20 minutes, the temperature was raised to 65°C and stirred for 10 minutes. Then 0.114g (i.e., 0.0004mol) of octadecyl acrylate monomer was added to the reaction flask with a syringe and the reaction was continued for 3 hours;

[0112] (S2) pouring the product (polymer product solution) obtained after step (S1) into methanol to precipitate the solid, which is the CO2-induced reactive thickening polymer surface agent.

[0113] In addition, the CO2-induced reactive type viscosity-increasing polymerizing agent has the following structure:

[0114]

[0115] Among them, x:y:z=100:150:4;

[0116] m is 5 and n is 17.

[0117] The viscosity average molecular weight of the CO2-induced reactive viscosity enhancing agent is 30145 g / mol.

[0118] Example 5

[0119] This embodiment is intended to illustrate the CO2-induced reaction-type viscosity-increasing polymerizing agent prepared by the method of the present invention.

[0120] The CO2-induced reactive viscosity-increasing polymer was prepared in the same manner as in Example 1, except that N-acryloyl (trimethylol) aminomethane was replaced with

[0121] In addition, the CO2-induced reactive viscosity-increasing polymer surfactant has the following structure:

[0122]

[0123] Among them, x:y:z=100:30:5;

[0124] m is 5 and n is 17.

[0125] The viscosity average molecular weight of the CO2-induced reactive viscosity-increasing polymer is 34860 ​​g / mol.

[0126] Example 6

[0127] This embodiment is intended to illustrate the CO2-induced reaction-type viscosity-increasing polymerizing agent prepared by the method of the present invention.

[0128] The CO2-induced reactive viscosity-increasing polymer was prepared in the same manner as in Example 1, except that N-acryloyl (trimethylol) aminomethane was replaced with

[0129] In addition, the CO2-induced reactive type viscosity-increasing polymerizing agent has the following structure:

[0130]

[0131] Among them, x:y:z=100:30:5;

[0132] m is 5 and n is 17.

[0133] The viscosity average molecular weight of the CO2-induced reactive viscosity-increasing polymer is 36630 g / mol.

[0134] Example 7

[0135] This embodiment is intended to illustrate the CO2-induced reaction-type viscosity-increasing polymerizing agent prepared by the method of the present invention.

[0136] The CO2-induced reactive viscosity-increasing polymer was prepared in the same manner as in Example 1, except that N-acryloyl (trimethylol) aminomethane was replaced with

[0137]

[0138] In addition, the CO2-induced reactive type viscosity-increasing polymerizing agent has the following structure:

[0139]

[0140] Among them, x:y:z=100:30:5;

[0141] m is 5 and n is 17.

[0142] The viscosity average molecular weight of the CO2-induced reactive viscosity-increasing polymer is 36780 g / mol.

[0143] Example 8

[0144] This embodiment is intended to illustrate the CO2-induced reaction-type viscosity-increasing polymerizing agent prepared by the method of the present invention.

[0145] The CO2-induced reactive viscosity-increasing polymer was prepared in the same manner as in Example 1, except that N-acryloyl (trimethylol) aminomethane was replaced with

[0146]

[0147] Replace octadecyl acrylate with dodecyl acrylate.

[0148] In addition, the CO2-induced reactive type viscosity-increasing polymerizing agent has the following structure:

[0149]

[0150] Among them, x:y:z=100:30:5;

[0151] m is 5 and n is 11.

[0152] The viscosity average molecular weight of the CO2-induced reactive viscosity-increasing polymer is 36820 g / mol.

[0153] Example 9

[0154] This embodiment is intended to illustrate the CO2-induced reaction-type viscosity-increasing polymerizing agent prepared by the method of the present invention.

[0155] The CO2-induced reactive viscosity-increasing polymer was prepared in the same manner as in Example 1, except that N-acryloyl (trimethylol) aminomethane was replaced with

[0156]

[0157] Replace octadecyl acrylate with dodecyl acrylate.

[0158] In addition, the CO2-induced reactive type viscosity-increasing polymerizing agent has the following structure:

[0159]

[0160] Among them, x:y:z=100:30:5;

[0161] m is 5 and n is 11.

[0162] The viscosity average molecular weight of the CO2-induced reactive viscosity-increasing polymer is 37550 g / mol.

[0163] Comparative Example 1

[0164] (S1) Add 26.25 g (i.e., 0.075 mol)

[0165] The monomer and 0.27g of azodiisopropylimidazoline hydrochloride (AIBI) initiator were added with 300mL of deionized water solvent. After N2 bubbling for 20 minutes, the temperature was raised to 70°C and stirred for 10 minutes. Then 0.81g (i.e., 0.0025mol) of octadecyl acrylate monomer was added to the reaction flask with a syringe and the reaction was continued for 5 hours;

[0166] (S2) pouring the product (polymer product solution) obtained after step (S1) into methanol to precipitate to obtain a solid product.

[0167] In addition, the CO2-induced reactive type viscosity-increasing polymerizing agent has the following structure:

[0168]

[0169] Among them, y:z=150:5;

[0170] m is 5 and n is 17.

[0171] And the viscosity average molecular weight of the polymer is 38200 g / mol.

[0172] Comparative Example 2

[0173] (S1) Add 17.5 g (i.e., 0.1 mol) of N-acryloyl (trimethylol) aminomethane and 0.28 g of potassium persulfate initiator to a flask, and add 280 mL of deionized water solvent; after N2 bubbling for 20 minutes, heat to 60° C. and react for 10 minutes under stirring. Then, add 1.62 g (i.e., 0.005 mol) of octadecyl acrylate monomer to the reaction flask with a syringe, and continue to react for 5 hours;

[0174] (S2) pouring the product (polymer product solution) obtained after step (S1) into methanol to precipitate to obtain a solid product.

[0175] In addition, the CO2-induced reactive type viscosity-increasing polymerizing agent has the following structure:

[0176]

[0177] Among them, x:z=100:5;

[0178] n is 17.

[0179] And the viscosity average molecular weight of the polymer is 25780 g / mol.

[0180] Comparative Example 3

[0181] The surfactant was prepared in the same manner as in Example 1, except that the monomer "N-acryloyl (trihydroxymethyl) aminomethane" was replaced with "acrylamide", that is, the polyhydroxy monomer was replaced with acrylamide commonly used in the petroleum field.

[0182] Results The CO2-induced reactive viscosity-enhancing agent has the following structure:

[0183]

[0184] Among them, x:y:z=100:30:5;

[0185] m is 5 and n is 17.

[0186] And the viscosity average molecular weight of the polymer is 30150 g / mol.

[0187] Application Example 1

[0188] The CO2-induced reactive thickening polymer prepared in Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Example 7, Example 8 and Example 9 were mixed with water to form a solution with a concentration of 2wt%. The viscosity of the solution was tested at 25°C and is shown in Table 1. After continuously introducing CO2 into the solution, the hydroxyl and aldehyde groups were induced to undergo a coupling reaction, and the viscosity of the system gradually increased until it was completely gelled on the fifth day. The viscosity of the gel was tested at 25°C and is shown in Table 1.

[0189] Application Example 2

[0190] The polymers prepared in Comparative Examples 1, 2 and 3 were tested as gas channeling blocking agents in CO2 flooding in the same manner as in Application Example 1. The solution viscosity and gel viscosity are shown in Table 1.

[0191] Table 1

[0192]

[0193]

[0194] It can be seen from the above results that the CO2-induced reactive viscosity-increasing polymer surface agent of the present invention can induce a coupling reaction between the hydroxyl group and the aldehyde group when CO2 is injected to generate a gel, thereby increasing viscosity and achieving the effect of blocking channeling. It has low initial viscosity, strong fluidity, and good injectability. After cross-linking, it has good chemical stability and can achieve long-term effective blocking.

[0195] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A CO2-induced reactive viscosity-increasing polymerizing agent, characterized in that: The CO2-induced reactive type viscosity-increasing polymerizing agent has a structure shown in formula (1); Wherein, R is selected from at least one of formula (2) to formula (7): x:y:z=100: (30-150): (1-5); m is 1-7, n is 5-20.

2. The CO2-induced reactive thickening agent according to claim 1, Where x is: y: z=100: (30-150): (2-5); and / or, m is 5-7, preferably, m is 5-6; And / or, n is 8-18, preferably, n is 15-17.

3. The CO2-induced reactive thickening agent according to claim 1 or 2, wherein: The viscosity average molecular weight of the CO2 induced reactive viscosity increasing polymerizing agent is 20000-85000 g / mol.

4. A method for preparing a CO2-induced reactive viscosity-increasing polymerizing agent, characterized in that: The preparation method comprises: (S1) in the presence of an initiator, a polyhydroxy monomer containing a terminal double bond represented by formula (8), an aldehyde monomer containing a terminal double bond represented by formula (9), a hydrophobic long-chain acrylate represented by formula (10) and a solvent are contacted to react; Wherein, R is selected from at least one of formula (2) to formula (7): Wherein, m is 1-7; Wherein, n is 5-20; (S2) The product obtained in step (S1) is precipitated in methanol to obtain a CO2-induced reactive thickening polymerizing agent.

5. The preparation method according to claim 4, wherein The molar ratio of the polyhydroxy monomer containing a terminal double bond shown in formula (8), the aldehyde monomer containing a terminal double bond shown in formula (9), and the hydrophobic long-chain acrylate shown in formula (10) is 100:(30-150):(1-5), preferably 100:(50-100):(3-5).

6. The preparation method according to claim 4 or 5, wherein: The initiator is selected from at least one of ammonium persulfate, potassium persulfate, azobisisopropylimidazoline hydrochloride and azobisisobutylamidine hydrochloride; and / or, the solvent is water; And / or, based on the total amount A of the polyhydroxy monomer containing a terminal double bond shown in formula (8), the aldehyde monomer containing a terminal double bond shown in formula (9), and the hydrophobic long-chain acrylate shown in formula (10), the amount of the initiator is 0.1-2wt%A, preferably 0.1-1wt%A, and the amount of the solvent is 10-30A.

7. The preparation method according to claim 4, wherein The reaction conditions include: under N2 atmosphere, temperature is 50-80°C, time is 2-12h; preferably, temperature is 60-70°C, time is 5-6h.

8. A CO2-induced reactive viscosity-enhancing surface-polymerizing agent prepared by the preparation method described in any one of claims 4 to 7.

9. Use of the CO2 induced reaction type viscosity increasing polymerizing agent as claimed in any one of claims 1 to 3 and 8 as a gas channeling blocking agent in CO2 flooding.

10. The use according to claim 9, wherein: The CO2-induced reactive viscosity-enhancing surface agent is prepared into an aqueous solution with a concentration of 0.5-2 wt %; Preferably, at 25° C., the viscosity of the 2 wt % polymer surfactant solution is 10-70 mPa·s; Preferably, at 25° C., when CO 2 is injected, the viscosity of the gel generated by the 2 wt % polymer surfactant solution is 9000-26000 mPa·s.

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