Temperature and salt resistant osmotic agent

Abstract

The present application relates to a kind of temperature and salt resistant imbibition agent, by the Mannich reaction of p-xylylenediamine with formaldehyde, formic acid is synthesized to obtain tetramethyl binary tertiary amine intermediate;The intermediate is reacted with alpha-bromine carboxylic acid under alkaline conditions to generate gemini betaine surfactant.Gemini betaine surfactant is compounded with one or two of non-ionic surfactant and small molecule alcohol, and temperature and salt resistant imbibition agent is prepared.The imbibition agent has the characteristics of easy entering matrix channel, anti-absorption, strong wetting reversal ability, temperature resistance can reach 150 DEG C, salt resistance can reach 15×10 4 mg / L, can meet the technical requirements of oil reservoir temperature ≤150 DEG C, salinity ≤15×10 4 mg / L low permeability oil reservoir imbibition oil recovery technology.

Description

Technical Field

[0001] This invention belongs to the field of oilfield chemical agent synthesis technology, specifically relating to a temperature- and salt-resistant permeation agent. Background Technology

[0002] Low-permeability oil and gas reservoirs, due to their low porosity and permeability, face challenges such as difficult water injection and complex extraction processes. The average recovery rate of low-permeability oilfields in my country is only 23.3%, 11.7% lower than the 35% of medium- and high-permeability oilfields. Currently, low-permeability oil and gas reservoirs account for more than half of the proven reserves. Considering my country's current national conditions, low-permeability reservoirs have become strategic replacement areas for crude oil resources. However, their poor porosity and permeability, strong reservoir heterogeneity, and poor water absorption capacity lead to low recovery rates. Therefore, the development of low-permeability oil reservoirs faces significant technical challenges.

[0003] Percolation recovery utilizes the entry of percolating fluids into the pores of reservoir rocks, altering the wettability of the matrix and reducing the oil-water interfacial tension. The wetting / percolating fluids displace the non-wetting fluids through capillary forces, often accompanied by spontaneous percolation without external pressure. Currently, percolators mainly include surfactants, nano-silica, and compound types. While all can reduce oil-water interfacial tension and alter matrix wettability, they suffer from poor temperature and salt resistance. For reservoirs with salinity higher than 30,000 mg / L, ordinary percolators are prone to salting out and cannot effectively dissolve in formation water. For reservoirs with temperatures above 100℃, some easily hydrolyzed functional groups will hydrolyze, losing the percolator's interfacial activity. To address the poor temperature and salt resistance of percolators, researchers have conducted targeted studies.

[0004] Chinese patent document CN114106806A discloses a temperature-resistant and salt-resistant nano-permeabilizer, its synthesis method, and its application. The provided temperature-resistant and salt-resistant nano-permeabilizer is composed of BrCH2CH2OSi(OCH2CH3)3, N-methylimidazole, and RO(CH2CH2O). n- The percolator is synthesized from 1CH2CH2OH and BrCH2COONa via a stepwise reaction. It has a temperature resistance of 150℃ and a total mineralization of 32868 mg / L. However, its synthesized product belongs to the silyl ether class of compounds, which is sensitive to acids and bases, easily hydrolyzed, unstable, has weak recombination ability with divalent ions, and low salt tolerance.

[0005] Chinese patent document CN114410286A discloses a temperature- and salt-resistant nano-permeable oil displacement agent, its preparation method, and its application. The temperature- and salt-resistant nano-permeable oil displacement agent comprises the following components: 20-40 parts by weight of active nanomaterials; 10-30 parts by weight of nonionic surfactants; and 10-30 parts by weight of anionic surfactants. The active nanomaterials are obtained by polymerizing raw materials containing double-bond modified sheet-like nanomaterials, hydrophilic monomers, and hydrophobic monomers. The operating temperature of this nano-permeable oil displacement agent is 70-120℃, and its salinity is 10000 mg / L NaCl to 100000 mg / L NaCl. The nano-permeable oil displacement agent is designed with a twin surfactant. The hydrophobic group is relatively long, while the hydrophilic carboxylic acid group is less salt-resistant than the sulfonic acid group. The designed nonionic surfactant... It has a large molecular weight and a low cloud point in salt water. Summary of the Invention

[0006] The purpose of this invention is to provide a temperature- and salt-resistant percolator to solve the problem of insufficient temperature and salt resistance in existing oil displacement percolators.

[0007] To achieve the above objectives, the technical solution adopted by the present invention for a temperature- and salt-resistant permeation agent is as follows:

[0008] A temperature- and salt-resistant permeation agent comprises a geminate betaine surfactant and water; it further comprises one or two of a nonionic surfactant and a small molecule alcohol; the structural formula of the geminate betaine surfactant is:

[0009]

[0010] Wherein, R is a chain saturated alkane of C12 to C16;

[0011] The mass ratio of the geminate surfactant, nonionic surfactant, and small molecule alcohol is (0.1-0.5):(0.1-0.3):(0.1-0.2).

[0012] The beneficial effects of this invention are as follows: This invention designs a gemini betaine surfactant with a gemini and positive and negative double charge structure. It has two hydrophilic groups, strong site-occupancy ability, and two hydrophobic groups, strong oil displacement ability; it has positive and negative double charges, no precipitation at the isoelectric point, and strong salt resistance; the two hydrophilic groups and two hydrophobic chains are linked together by chemical bonds using alkylbenzene rigid groups, which enhances the stability of the system and improves its temperature resistance.

[0013] The above-mentioned combination of geminate betaine surfactant, nonionic surfactant, and small molecule alcohol gives the permeabilizer the characteristics of easy entry into matrix pores, anti-adsorption, and strong wetting reversal ability, achieving a temperature resistance of 150℃ and a salt resistance of 15×10⁻⁶. 4 mg / L.

[0014] The percolator prepared in this invention contains three components with varying carbon counts: a geminate betaine surfactant with 29-36 carbons and a hydrophobic chain with 12-16 carbons; a nonionic surfactant with 8-10 carbons; and a small molecule alcohol with 2-6 carbons. These different molecular sizes and carbon chain lengths work synergistically. The small molecule alcohol increases the fluidity of the interfacial film and accelerates the decrease in interfacial tension. The medium-molecular-weight nonionic surfactant, with its rapid action, acts as a prelude, with its hydrophilic groups interacting with clay substances earlier and its hydrophobic groups aligning outwards to reduce subsequent percolator loss. The relatively large-molecular-weight geminate betaine surfactant has strong occupancy capabilities, displacing crude oil from the matrix.

[0015] In order to enable the hydrophilic groups in the molecular structure to interact with the clay material in advance and the hydrophobic groups to be arranged outward to reduce the loss of subsequent percolating agents, preferably, the nonionic surfactant is a C8-C10 alkyl alcohol polyoxyethylene ether.

[0016] More preferably, the nonionic surfactant is any one of isooctanol polyoxyethylene ether, decanol polyoxyethylene ether, and octadecanol polyoxyethylene ether.

[0017] To further increase the fluidity of the interfacial film and accelerate the rate of decrease in interfacial tension, preferably, the small molecule alcohol is a C2-C6 monohydric or dihydric alcohol.

[0018] More preferably, the small molecule alcohol is any one of ethylene glycol, n-butanol, propylene glycol, and propanol.

[0019] In order to reduce the surface tension and interfacial tension of the temperature and salt resistant permeabilizer and improve its salt and temperature resistance, preferably, the mass percentage of the geminate betaine surfactant in the temperature and salt resistant permeabilizer is 0.1 to 0.5‰.

[0020] The preparation method of the temperature- and salt-resistant permeation agent includes the preparation step of the geminate betaine surfactant, and the step of mixing the nonionic surfactant, the small molecule alcohol and water; the preparation method of the geminate betaine surfactant includes: synthesizing a tetramethyl ditertiary amine intermediate by reacting p-phenylenediamine with formaldehyde and formic acid via a Mannich reaction; the intermediate is then reacted with α-bromocarboxylic acid under alkaline conditions to generate the intermediate; the general formula of the α-bromocarboxylic acid is RBrCHCOOH, wherein R is a C12-C16 chain saturated alkane.

[0021] The beneficial effects of the above technical solution are as follows: In the preparation method of the temperature- and salt-resistant permeabilizer of the present invention, the prepared gemini betaine surfactant with gemini and positive and negative double charge structures is combined with one or two of nonionic surfactants and small molecule alcohols. Through the combination of different molecular sizes and different carbon chain lengths, the permeabilizer has the characteristics of easy entry into matrix pores, anti-adsorption, and strong wetting reversal ability, achieving a temperature resistance of 150℃ and a salt resistance of 15×10⁻⁶. 4 mg / L. Small molecule alcohols can increase the fluidity of the interfacial film and accelerate the rate of decrease in interfacial tension; medium-molecular-weight nonionic surfactants, with their rapid dispersibility, act as the initial "troops," with hydrophilic groups in their molecular structure interacting with clay substances ahead of time, and hydrophobic groups aligning outwards to reduce the loss of subsequent percolators. Gemini betaine surfactants, with relatively large molecular weights, have strong occupancy capabilities, displacing crude oil from the matrix.

[0022] Specifically, the synthetic route for the geminate betaine surfactant is as follows:

[0023]

[0024] More preferably, the α-bromocarboxylic acid is one of α-bromododecylacetic acid, α-bromotetradecylacetic acid, or α-bromohexadecylacetic acid.

[0025] To ensure that the reaction between p-phenylenediamine and formaldehyde and formic acid is sufficient, rapid and efficient, preferably, the temperature for synthesizing the tetramethyl ditertiary amine intermediate is 50-80°C and the time is 8-48 hours.

[0026] More preferably, the temperature for synthesizing the tetramethyl ditertiary amine intermediate is 50–70°C, and the time is 8–24 h.

[0027] To enhance the stability and temperature resistance of the geminate betaine surfactant, preferably, the molar ratio of p-phenylenediamine, formaldehyde, and formic acid is (1-1.1):(2-2.2):(2.1-2.2).

[0028] More preferably, the molar ratio of the p-phenylenediamine mixed with formaldehyde and formic acid is 1:(2-2.1):(2.1-2.2).

[0029] To ensure a mild and complete reaction between the intermediate and α-bromocarboxylic acid, preferably, the intermediate is reacted with α-bromocarboxylic acid at a temperature of 50–100°C for 8–48 h and at a pH of 8–10.

[0030] More preferably, the intermediate is reacted with α-bromocarboxylic acid at a temperature of 50–80°C for 8–24 hours and at a pH of 8–9.

[0031] To enhance the salt resistance of the geminate betaine surfactant, preferably, the molar ratio of p-phenylenediamine to α-bromocarboxylic acid is (1-1.1):(2-2.5).

[0032] The above-mentioned temperature- and salt-resistant permeation agents are used in the development of low-permeability oil reservoirs.

[0033] The beneficial effects of the above technical solution are as follows: the temperature and salt resistant permeabilizer provided in this application has good temperature and salt resistance, low permeability, and a mineralization resistance of 15×10. 4 With a concentration of mg / L and a temperature resistance of 150℃, it can be applied to the development of low-permeability oil reservoirs, improve the recovery rate of low-permeability fractured oil fields, and has important significance and economic value for improving the development efficiency of low-permeability oil reservoirs. Detailed Implementation

[0034] Existing oil displacement and permeation agents lack sufficient temperature and salt resistance. This invention proposes a temperature and salt resistant permeation agent, which includes a geminate betaine surfactant and water; it also includes one or two of a nonionic surfactant and a small molecule alcohol.

[0035] The structural formula of the described geminate betaine surfactant is:

[0036]

[0037] Wherein, R is a chain saturated alkane of C12 to C16;

[0038] The mass ratio of the geminate surfactant, nonionic surfactant, and small molecule alcohol is (0.1-0.5):(0.1-0.3):(0.1-0.2).

[0039] The technical concept of this invention is as follows: This invention designs and synthesizes a gemini betaine surfactant with a gemini and positive and negative double-charge structure, which has the characteristics of strong site-occupancy ability, strong oil-displacing ability of double hydrophobic groups, strong salt resistance, enhanced system stability, and enhanced temperature resistance. It is compounded with one or two nonionic surfactants and small molecule alcohols, and through the combination of different molecular sizes and carbon chain lengths, the synergistic effect makes the permeabilizer easy to enter the matrix channels, has strong anti-adsorption and wetting reversal ability, achieving a temperature resistance of 150℃ and a salt resistance of 15 × 10⁻⁶. 4 mg / L.

[0040] Specifically, the method for preparing the geminate betaine surfactant includes the following steps:

[0041] (1) In an atmospheric pressure reactor equipped with a heating, stirring and temperature control system, p-phenylenediamine, formaldehyde and formic acid are fed in a molar ratio of (1-1.1):(2-2.2):(2.1-2.2), an appropriate amount of solvent is added, and the mixture is stirred at a constant temperature of 50-80℃ for 8-48 hours.

[0042] (2) Add an appropriate amount of alkaline substance to the above reaction solution to adjust the pH to 8-10, add α-bromocarboxylic acid at a molar ratio of 2-2.5 times that of p-phenylenediamine, and stir at a constant temperature of 50-100℃ for 8-48 hours;

[0043] (3) Cool to room temperature, adjust pH to 6-7, and filter to obtain solid betaine surfactant.

[0044] Preferably, the solvent is at least one of deionized water or ethanol.

[0045] Preferably, the alkaline substance is selected from at least one of NaOH solution, KOH solution or ammonia water.

[0046] In the following examples and comparative examples, the CAS number of the nonionic surfactants isooctanol polyoxyethylene ether is No. 26468-86-0, the CAS number of decanol polyoxyethylene ether is No. 26183-52-8, and the CAS number of octadecanol polyoxyethylene ether is No. 71060-57-6.

[0047] The implementation process of the present invention will be described in detail below with reference to specific embodiments.

[0048] I. Specific Embodiments of the Temperature-Resistant and Salt-Resistant Permeation Agent of the Present Invention

[0049] Example 1

[0050] The temperature- and salt-resistant permeabilizing agent of this embodiment is composed of geminate betaine surfactant, nonionic surfactant, small molecule alcohol, and water. The mass fractions of geminate betaine surfactant, nonionic surfactant, and small molecule alcohol in this permeabilizing agent are 0.1‰, 0.1‰, and 0.1‰, respectively, and water is used as the solvent; wherein:

[0051] The structural formula of the geminate betaine surfactant is:

[0052]

[0053] Wherein, R is a C12 chain saturated alkane;

[0054] The nonionic surfactant is: isooctanol polyoxyethylene ether;

[0055] The small molecule alcohol is ethylene glycol.

[0056] The method for preparing the temperature- and salt-resistant permeation agent in this embodiment includes the following steps:

[0057] Step 1: Preparation of Gemini Betaine Surfactant:

[0058] (1) In a three-necked round-bottom flask, p-phenylenediamine, formaldehyde, and formic acid were added in sequence, with each component in a molar ratio of 1:2.1:2.1 and a total mass of 30g. 150ml of ethanol was added and the mixture was stirred at 50℃ for 8h.

[0059] (2) Add 5.6 mL of 30% NaOH to the above reaction solution to adjust the pH to 8, add α-bromododecyl acetic acid at a molar ratio of 2.0 times that of p-phenylenediamine, and stir at 50°C for 8 h.

[0060] (3) Cool to room temperature, adjust pH to 6, and filter to obtain solid betaine surfactant.

[0061] Step 2: Preparation of temperature- and salt-resistant permeabilizing agent:

[0062] Take 100 parts of water and slowly add 0.1‰ geminate surfactant, 0.1‰ nonionic surfactant and 0.1‰ small molecule alcohol in sequence while stirring. Stir for more than 1 hour to fully dissolve each component and obtain a temperature and salt resistant permeabilizer.

[0063] Example 2

[0064] The temperature- and salt-resistant permeabilizing agent of this embodiment is composed of geminate betaine surfactant, nonionic surfactant, small molecule alcohol, and water. The mass fractions of geminate betaine surfactant, nonionic surfactant, and small molecule alcohol in this permeabilizing agent are 0.2‰, 0.2‰, and 0.2‰, respectively, and water is used as the solvent; wherein:

[0065] The structural formula of the geminate betaine surfactant is:

[0066]

[0067] Wherein, R is a C14 chain saturated alkane;

[0068] The nonionic surfactant is: decanol polyoxyethylene ether;

[0069] The small molecule alcohol is n-butanol.

[0070] The method for preparing the temperature- and salt-resistant permeation agent in this embodiment includes the following steps:

[0071] Step 1: Preparation of Gemini Betaine Surfactant:

[0072] (1) In a three-necked round-bottom flask, p-phenylenediamine, formaldehyde, and formic acid were added in sequence, with each component in a molar ratio of 1:2.1:2.2 and a total mass of 30g. 120mL of ethanol was added and the mixture was stirred at 60℃ for 12h.

[0073] (2) Add 5.6 mL of 30% NaOH to the above reaction solution to adjust the pH to 8, add α-bromotetradecyl acetic acid at a molar ratio of 2 to p-phenylenediamine, and stir at 60°C for 12 h.

[0074] (3) Cool to room temperature, adjust pH to 6, and filter to obtain solid betaine surfactant.

[0075] Step 2: Preparation of temperature- and salt-resistant permeabilizing agent:

[0076] Take 100 parts of water and slowly add 0.2‰ geminate surfactant, 0.2‰ nonionic surfactant and 0.2‰ small molecule alcohol in sequence while stirring. Stir for more than 1 hour to fully dissolve each component and obtain a temperature and salt resistant permeabilizer.

[0077] Example 3

[0078] The temperature- and salt-resistant penetrant of this embodiment is composed of geminate betaine surfactant, nonionic surfactant, small molecule alcohol, and water. The mass fractions of geminate betaine surfactant, nonionic surfactant, and small molecule alcohol in this penetrant are 0.3‰, 0.3‰, and 0.2‰, respectively, and water is used as the solvent; wherein:

[0079] The structural formula of the geminate betaine surfactant is:

[0080]

[0081] Wherein, R is a C16 chain saturated alkane;

[0082] The nonionic surfactant is: octadecanol polyoxyethylene ether;

[0083] The small molecule alcohol is propylene glycol.

[0084] The method for preparing the temperature- and salt-resistant permeation agent in this embodiment includes the following steps:

[0085] Step 1: Preparation of Gemini Betaine Surfactant:

[0086] (1) In a three-necked round-bottom flask, p-phenylenediamine, formaldehyde, and formic acid were added in sequence, with each component in a molar ratio of 1:2:2.2 and a total mass of 29g. 110mL of ethanol was added, and the mixture was stirred at 65℃ for 20h.

[0087] (2) Add 5.7 mL of 30% NaOH to the above reaction solution to adjust the pH to 9, add α-bromohexadecyl acetic acid at a molar ratio of 2.1 times that of p-phenylenediamine, and stir at 65°C for 20 h.

[0088] (3) Cool to room temperature, adjust pH to 6, and filter to obtain solid betaine surfactant.

[0089] Step 2: Preparation of temperature- and salt-resistant permeabilizing agent:

[0090] Take 100 parts of water and slowly add them in sequence while stirring: 0.3‰ geminate surfactant, 0.3‰ nonionic surfactant and 0.2‰ small molecule alcohol. Stir for more than 1 hour to fully dissolve each component to obtain the penetrant.

[0091] Example 4

[0092] The temperature- and salt-resistant permeabilizing agent of this embodiment is composed of geminate betaine surfactant, nonionic surfactant, small molecule alcohol, and water. The mass fractions of geminate betaine surfactant, nonionic surfactant, and small molecule alcohol in this permeabilizing agent are 0.2‰, 0.1‰, and 0.2‰, respectively, and water is used as the solvent; wherein:

[0093] The structural formula of the geminate betaine surfactant is:

[0094]

[0095] Wherein, R is a C12 chain saturated alkane;

[0096] The nonionic surfactant is: isooctanol polyoxyethylene ether;

[0097] The small molecule alcohol is propanol.

[0098] The method for preparing the temperature- and salt-resistant permeation agent in this embodiment includes the following steps:

[0099] Step 1: Preparation of Gemini Betaine Surfactant:

[0100] (1) In a three-necked round-bottom flask, p-phenylenediamine, formaldehyde, and formic acid were added in sequence, with each component in a molar ratio of 1:2:2.2 and a total mass of 30g. 120mL of ethanol was added and the mixture was stirred at 65℃ for 20h.

[0101] (2) Add 5.8 mL of 30% NaOH to the above reaction solution to adjust the pH to 9, add α-bromododecyl acetic acid at a molar ratio of 2.1 times that of p-phenylenediamine, and stir at 70°C for 20 h.

[0102] (3) Cool to room temperature, adjust pH to 7, and filter to obtain solid betaine surfactant.

[0103] Step 2: Preparation of temperature- and salt-resistant permeabilizing agent:

[0104] Take 100 parts of water and slowly add 0.2‰ geminate surfactant, 0.1‰ nonionic surfactant and 0.2‰ small molecule alcohol in sequence while stirring. Stir for more than 1 hour to fully dissolve each component to obtain the penetrant.

[0105] Example 5

[0106] The temperature- and salt-resistant permeabilizing agent of this embodiment is composed of geminate betaine surfactant, nonionic surfactant, small molecule alcohol, and water. The mass fractions of geminate betaine surfactant, nonionic surfactant, and small molecule alcohol in this permeabilizing agent are 0.3‰, 0.2‰, and 0.2‰, respectively, and water is used as the solvent; wherein:

[0107] The structural formula of the geminate betaine surfactant is:

[0108]

[0109] Wherein, R is a C14 chain saturated alkane;

[0110] The nonionic surfactant is: decanol polyoxyethylene ether;

[0111] The small molecule alcohol is n-butanol.

[0112] The method for preparing the temperature- and salt-resistant permeation agent in this embodiment includes the following steps:

[0113] Step 1: Preparation of Gemini Betaine Surfactant:

[0114] (1) In a three-necked round-bottom flask, p-phenylenediamine, formaldehyde, and formic acid were added in sequence, with each component in a molar ratio of 1:2.1:2.2 and a total mass of 30g. 110mL of ethanol was added and the mixture was stirred at 70℃ for 24h.

[0115] (2) Add 5.6 mL of 30% NaOH to the above reaction solution to adjust the pH to 9, add α-bromotetradecyl acetic acid at a molar ratio of 2.2 times that of p-phenylenediamine, and stir at 70°C for 24 h.

[0116] (3) Cool to room temperature, adjust pH to 6, and filter to obtain solid betaine surfactant.

[0117] Step 2: Preparation of temperature- and salt-resistant permeabilizing agent:

[0118] Take 100 parts of water and slowly add 0.3‰ geminate surfactant, 0.2‰ nonionic surfactant and 0.2‰ small molecule alcohol in sequence while stirring. Stir for more than 1 hour to fully dissolve each component and obtain the penetrant.

[0119] Example 6

[0120] The temperature- and salt-resistant permeabilizing agent of this embodiment is composed of geminate betaine surfactant, nonionic surfactant, small molecule alcohol, and water. The mass fractions of geminate betaine surfactant, nonionic surfactant, and small molecule alcohol in this permeabilizing agent are 0.4‰, 0.1‰, and 0.1‰, respectively, and water is used as the solvent; wherein:

[0121] The structural formula of the geminate betaine surfactant is:

[0122]

[0123] Wherein, R is a C16 chain saturated alkane;

[0124] The nonionic surfactant is: isooctanol polyoxyethylene ether;

[0125] The small molecule alcohol is propylene glycol.

[0126] The method for preparing the temperature- and salt-resistant permeation agent in this embodiment includes the following steps:

[0127] Step 1: Preparation of Gemini Betaine Surfactant:

[0128] (1) In a three-necked round-bottom flask, p-phenylenediamine, formaldehyde, and formic acid were added in sequence, with each component in a molar ratio of 1:2.1:2.1. 150 mL of ethanol was added and the mixture was stirred at 75 °C for 24 h.

[0129] (2) Add 5.6 mL of 30% NaOH to the above reaction solution to adjust the pH to 9, add α-bromohexadecyl acetic acid at a molar ratio of 2.3 times that of p-phenylenediamine, and stir at 75°C for 24 h.

[0130] (3) Cool to room temperature, adjust pH to 7, and filter to obtain solid betaine surfactant.

[0131] Step 2: Preparation of temperature- and salt-resistant permeabilizing agent:

[0132] Take 100 parts of water and slowly add 0.4‰ geminate surfactant, 0.1‰ nonionic surfactant and 0.1‰ small molecule alcohol in sequence while stirring. Stir for more than 1 hour to fully dissolve each component to obtain the penetrant.

[0133] Example 7

[0134] The temperature- and salt-resistant permeabilizing agent of this embodiment is composed of geminate betaine surfactant, nonionic surfactant, small molecule alcohol, and water. The mass fractions of geminate betaine surfactant, nonionic surfactant, and small molecule alcohol in this permeabilizing agent are 0.5‰, 0.2‰, and 0.1‰, respectively, and water is used as the solvent; wherein:

[0135] The structural formula of the geminate betaine surfactant is:

[0136]

[0137] Wherein, R is a C12 chain saturated alkane;

[0138] The nonionic surfactant is: octadecanol polyoxyethylene ether;

[0139] The small molecule alcohol is n-butanol.

[0140] The method for preparing the temperature- and salt-resistant permeation agent in this embodiment includes the following steps:

[0141] Step 1: Preparation of Gemini Betaine Surfactant:

[0142] (1) In a three-necked round-bottom flask, p-phenylenediamine, formaldehyde, and formic acid were added in sequence, with each component in a molar ratio of 1:2.2:2.2 and a total mass of 30g. 120mL of ethanol was added and the mixture was stirred at 75℃ for 32h.

[0143] (2) Add 5.6 mL of 30% NaOH to the above reaction solution to adjust the pH to 8, add α-bromododecyl acetic acid at a molar ratio of 2.4 times that of p-phenylenediamine, and stir at 80°C for 32 h.

[0144] (3) Cool to room temperature, adjust pH to 7, and filter to obtain solid betaine surfactant.

[0145] Step 2: Preparation of temperature- and salt-resistant permeabilizing agent:

[0146] Take 100 parts of water and slowly add 0.5‰ geminate surfactant, 0.2‰ nonionic surfactant and 0.1‰ small molecule alcohol in sequence while stirring. Stir for more than 1 hour to fully dissolve each component and obtain the penetrant.

[0147] Example 8

[0148] The temperature- and salt-resistant permeabilizing agent of this embodiment is composed of geminate betaine surfactant, nonionic surfactant, small molecule alcohol, and water. The mass fractions of geminate betaine surfactant, nonionic surfactant, and small molecule alcohol in this permeabilizing agent are 0.5‰, 0.1‰, and 0.1‰, respectively, and water is used as the solvent; wherein:

[0149] The structural formula of the geminate betaine surfactant is:

[0150]

[0151] Wherein, R is a C14 chain saturated alkane;

[0152] The nonionic surfactant is: isooctanol polyoxyethylene ether;

[0153] The small molecule alcohol is ethylene glycol.

[0154] The method for preparing the temperature- and salt-resistant permeation agent in this embodiment includes the following steps:

[0155] Step 1: Preparation of Gemini Betaine Surfactant:

[0156] (1) In a three-necked round-bottom flask, p-phenylenediamine, formaldehyde, and formic acid were added in sequence, with each component in a molar ratio of 1:2.1:2.2 and a total mass of 30g. 120mL of ethanol was added and the mixture was stirred at 80℃ for 48h.

[0157] (2) Add 5.7 mL of 30% NaOH to the above reaction solution to adjust the pH to 10, add α-bromotetradecyl acetic acid at a molar ratio of 2.5 times that of p-phenylenediamine, and stir at 85°C for 48 h.

[0158] (3) Cool to room temperature, adjust pH to 6, and filter to obtain solid betaine surfactant.

[0159] Step 2: Preparation of temperature- and salt-resistant permeabilizing agent:

[0160] Take 100 parts of water and slowly add 0.5‰ geminate surfactant, 0.1‰ nonionic surfactant and 0.1‰ small molecule alcohol in sequence while stirring. Stir for more than 1 hour to fully dissolve each component and obtain the penetrant.

[0161] Example 9

[0162] The temperature- and salt-resistant permeabilizing agent of this embodiment is composed of geminate betaine surfactant, nonionic surfactant, small molecule alcohol, and water. The mass fractions of geminate betaine surfactant, nonionic surfactant, and small molecule alcohol in this permeabilizing agent are 0.3‰, 0.2‰, and 0.1‰, respectively, and water is used as the solvent; wherein:

[0163] The structural formula of the geminate betaine surfactant is:

[0164]

[0165] Wherein, R is a C16 chain saturated alkane;

[0166] The nonionic surfactant is: decanol polyoxyethylene ether;

[0167] The small molecule alcohol is ethylene glycol.

[0168] The method for preparing the temperature- and salt-resistant permeation agent in this embodiment includes the following steps:

[0169] Step 1: Preparation of Gemini Betaine Surfactant:

[0170] (1) In a three-necked round-bottom flask, p-phenylenediamine, formaldehyde, and formic acid were added in sequence, with each component in a molar ratio of 1:2:2.2 and a total mass of 30g. 150mL of ethanol was added and the mixture was stirred at 80℃ for 48h.

[0171] (2) Add 5.8 mL of 30% NaOH to the above reaction solution to adjust the pH to 10, add α-bromohexadecyl acetic acid at a molar ratio of 2.0 times that of p-phenylenediamine, and stir at 100℃ for 48 h.

[0172] (3) Cool to room temperature, adjust pH to 7, and filter to obtain solid betaine surfactant.

[0173] Step 2: Preparation of temperature- and salt-resistant permeabilizing agent:

[0174] Take 100 parts of water and slowly add them in sequence while stirring: 0.3‰ geminate surfactant, 0.2‰ nonionic surfactant and 0.1‰ small molecule alcohol. Stir for more than 1 hour to fully dissolve each component to obtain the penetrant.

[0175] Example 10

[0176] The temperature- and salt-resistant permeabilizing agent of this embodiment is composed of geminate betaine surfactant, small molecule alcohol, and water. The mass fractions of geminate betaine surfactant and small molecule alcohol in this permeabilizing agent are 0.2‰ and 0.2‰, respectively, and water is used as the solvent; wherein:

[0177] The structural formula of the geminate betaine surfactant is:

[0178]

[0179] Wherein, R is a C14 chain saturated alkane;

[0180] The small molecule alcohol is ethylene glycol.

[0181] The method for preparing the temperature- and salt-resistant permeation agent in this embodiment includes the following steps:

[0182] Step 1: Preparation of Gemini Betaine Surfactant:

[0183] (1) In a three-necked round-bottom flask, p-phenylenediamine, formaldehyde, and formic acid were added in sequence, with each component in a molar ratio of 1:2:2.2 and a total mass of 30g. 120mL of ethanol was added and the mixture was stirred at 70℃ for 24h.

[0184] (2) Add 5.7 mL of 30% NaOH to the above reaction solution to adjust the pH to 9, add α-bromotetradecyl acetic acid at a molar ratio of 2.2 times that of p-phenylenediamine, and stir at 70°C for 24 h.

[0185] (3) Cool to room temperature, adjust pH to 6, and filter to obtain solid betaine surfactant.

[0186] Step 2: Preparation of temperature- and salt-resistant permeabilizing agent:

[0187] Take 100 parts of water and slowly add 0.2‰ geminate surfactant and 0.2‰ small molecule alcohol in sequence while stirring. Stir for more than 1 hour to fully dissolve each component and obtain the penetrant.

[0188] Example 11

[0189] The temperature- and salt-resistant permeabilizing agent of this embodiment is composed of geminate betaine surfactant, nonionic surfactant, and water. The mass fractions of geminate betaine surfactant and nonionic surfactant in this permeabilizing agent are 0.2‰ and 0.1‰, respectively, and the solvent is water; wherein:

[0190] The structural formula of the geminate betaine surfactant is:

[0191]

[0192] Wherein, R is a C16 chain saturated alkane;

[0193] The nonionic surfactant is isooctanol polyoxyethylene ether.

[0194] The method for preparing the temperature- and salt-resistant permeation agent in this embodiment includes the following steps:

[0195] Step 1: Preparation of Gemini Betaine Surfactant:

[0196] (1) In a three-necked round-bottom flask, p-phenylenediamine, formaldehyde, and formic acid were added in sequence, with each component in a molar ratio of 1:2:2.2 and a total mass of 30g. 120mL of ethanol was added and the mixture was stirred at 70℃ for 24h.

[0197] (2) Add 5.7 mL of 30% NaOH to the above reaction solution to adjust the pH to 9, add α-bromohexadecyl acetic acid at a molar ratio of 2.3 times that of p-phenylenediamine, and stir at 70°C for 24 h.

[0198] (3) Cool to room temperature, adjust pH to 6, and filter to obtain solid betaine surfactant.

[0199] Step 2: Preparation of temperature- and salt-resistant permeabilizing agent:

[0200] Take 100 parts of water and slowly add 0.2‰ geminate surfactant and 0.1‰ nonionic surfactant in sequence while stirring. Stir for more than 1 hour to fully dissolve each component and obtain the penetrant.

[0201] In the technical solution of this invention, the molar ratio of diphenylenediamine in the range of 1 to 1.1 can enhance the stability and temperature resistance of the geminate betaine surfactant.

[0202] II. Comparative Example

[0203] Comparative Example 1: Temperature- and salt-resistant permeabilizing agent and its preparation, without the addition of geminate betaine surfactant:

[0204] Composition of heat- and salt-resistant permeating agent: The heat- and salt-resistant permeating agent of Comparative Example 1 is composed of nonionic surfactant, small molecule alcohol and water. The mass fractions of nonionic surfactant and small molecule alcohol in the permeating agent are 0.1‰ and 0.2‰, respectively, and water is used as solvent; wherein: the nonionic surfactant is isooctanol polyoxyethylene ether; the small molecule alcohol is n-butanol.

[0205] Preparation of temperature- and salt-resistant permeabilizing agents:

[0206] Take 100 parts of water, and slowly add 0.1‰ nonionic surfactant and 0.2‰ small molecule alcohol in sequence while stirring. Stir for more than 1 hour to fully dissolve all components and obtain the penetrant.

[0207] III. Experimental Examples

[0208] Experiment Example 1: Performance Test of Temperature and Salt Resistance Permeabilizer

[0209] 15×10 on-site 4 The following performance tests were conducted on the temperature- and salt-resistant permeation agent sample solutions obtained in Examples 1-11 and Comparative Example 1, prepared with water with a mineralization of mg / L.

[0210] (1) Surface / interfacial tension

[0211] Surface tension: The prepared penetrant sample solution was tested with a surface tension meter at 25°C. The test was performed three times in a row and the average value was taken. The test results are shown in Table 1.

[0212] Interfacial tension: The prepared permeabilizer sample solution was tested at 70℃ with kerosene as the low-density phase using the rotating drop method specified in 3.3 of SY / T5370—2018. The test was performed three times and the average value was taken. The test results are shown in Table 1.

[0213] (2) Contact angle

[0214] Prepare a low-permeability sandstone core slice with a thickness of about 5 mm. After smoothing the cut surface with sandpaper, clean the sandstone core slice with alcohol and distilled water, and place it in an oven for one day to dry.

[0215] The core slices are placed in crude oil and soaked at 60°C for more than 48 hours to age them, so that they become oil-wet surfaces.

[0216] Remove the sandstone core, wipe the surface oil clean with paper, then soak it in the prepared permeabilizing agent sample solution and place it in an oven at 60℃ for 24 hours. Use a Krüger DSA25 contact angle meter to measure the contact angles of the core surface, air, and water phases. Take three consecutive measurements and average the results. The test results are shown in Table 1.

[0217] (3) Temperature resistance

[0218] After sealing the prepared permeabilizer sample solution, it was aged in a 150℃ oven for 15 days. The sample was then taken out and tested according to the above performance test method. The surface tension, interfacial tension and contact angle values ​​after high-temperature aging were recorded. The test results are shown in Table 1.

[0219] Table 1. Performance test data of Examples 1-11 and Comparative Example 1 before and after aging.

[0220]

[0221] Table 1 shows that the sample solutions prepared with the percolating agents in Examples 1-9 had surface tensions of 23.95-25.62 mN / m, oil-water interfacial tensions of 0.0005-0.0009 mN / m, and aqueous phase contact angles of 10.2°-11.2° before aging. After aging, the corresponding surface tensions were 23.52-25.01 mN / m, oil-water interfacial tensions of 0.0005-0.0010 mN / m, and aqueous phase contact angles of 10.2°-11.5°. It is evident that the sample solutions prepared with the percolating agents in Examples 1-9 had relatively low surface tensions, oil-water interfacial tensions, and aqueous phase contact angles; these values ​​remained essentially unchanged before and after aging. Therefore, the simultaneous use of geminate betaine surfactant, nonionic surfactant, and small molecule alcohol resulted in strong temperature and salt resistance, and the best percolation effect.

[0222] The sample solution prepared with the percolator in Example 10, without the addition of a nonionic surfactant, had a surface tension of 25.11 mN / m, an oil-water interfacial tension of 0.0009 mN / m, and an aqueous phase contact angle of 22.3° before aging. After aging, the corresponding surface tension was 25.58 mN / m, the oil-water interfacial tension was 0.0009 mN / m, and the aqueous phase contact angle was 25.3°. It can be seen that the surface tension and oil-water interfacial tension of the sample solution prepared with the percolator in Example 10 are basically the same as those in Examples 1-9, while the aqueous phase contact angle is larger than that in Examples 1-9. The surface tension and oil-water interfacial tension remain basically unchanged before and after aging, and the aqueous phase contact angle changes little after aging, indicating strong temperature and salt resistance.

[0223] The sample solution prepared with the percolator in Example 11, without the addition of small molecule alcohol, had a surface tension of 24.25 mN / m, an oil-water interfacial tension of 0.0006 mN / m, and an aqueous phase contact angle of 15.5° before aging. After aging, the corresponding surface tension was 24.11 mN / m, the oil-water interfacial tension was 0.0006 mN / m, and the aqueous phase contact angle was 15.8°. It can be seen that the sample solution prepared with the percolator in Example 11 has a surface tension and oil-water interfacial tension that are basically the same as those in Examples 1-9, but a larger contact angle compared to Examples 1-9. The surface tension, oil-water interfacial tension, and aqueous phase contact angle remain basically unchanged before and after aging, indicating strong temperature and salt resistance.

[0224] The sample solution prepared with the percolator of Comparative Example 1, without the addition of geminate betaine surfactant, showed a significant increase in the oil-water interfacial tension from 0.5 to 1.0 before and after aging, indicating insufficient temperature and salt resistance.

[0225] In summary, the gemini betaine surfactant designed in this invention possesses both positive and negative charges and strong salt resistance. The rigid alkylbenzene groups link two hydrophilic groups and two hydrophobic chains through chemical bonds, enhancing the system's stability and temperature resistance. This gemini betaine surfactant enables the permeabilizer to exhibit good temperature and salt resistance, and significantly reduces the oil-water interfacial tension and aqueous contact angle. When combined with one or two nonionic surfactants or small molecule alcohols, the resulting system exhibits good performance, with good oil-water interfacial tension control and wetting reversal ability. This allows the permeabilizer to easily enter matrix pores, resist adsorption, and possess strong wetting reversal ability, achieving a temperature resistance of 150℃ and a salt resistance of 15 × 10⁻⁶. 4 mg / L.

[0226] Experiment Example 2: Irradiation Recovery Experiment - Application of Temperature- and Salt-Resistant Irradiating Agents

[0227] The temperature- and salt-resistant permeation agents of Examples 1-11 and Comparative Example 1 were applied to the development of low-permeability reservoirs to test the permeation recovery rate.

[0228] 1) Core preparation: Prepare artificial sandstone cores and measure gas permeability and porosity; saturate the cores with formation crude oil under vacuum and pressure, and after saturation, age them in a 90℃ constant temperature oven for more than 24 hours, weighing and recording the mass of the saturated crude oil. 2) Place the saturated cores into a self-priming instrument containing the sample to be tested, allowing the cores to self-prime and discharge oil, recording the amount of oil discharged over time; when the volume of discharged oil does not change for 8 consecutive hours, record the total volume of discharged oil, and calculate the enhanced oil recovery rate; 3) Enhanced oil recovery rate / % = (mass of self-primed discharged oil / mass of saturated crude oil) × 100%. The enhanced oil recovery rates of Examples 1-11 and Comparative Example 1 are shown in Table 2.

[0229] Table 2. Data on seepage recovery rates for Examples 1-11 and Comparative Example 1.

[0230]

[0231] As shown in Table 2, the recovery rate of the permeabilizers in Examples 1-11 is over 65.8%, while the recovery rate of the permeabilizer in Comparative Example 1 is 10.3%. Therefore, the temperature- and salt-resistant permeabilizers provided by this invention can significantly improve the recovery rate, reaching over 65.8%.

[0232] The permeabilizer prepared by this invention is heat and salt resistant, with a temperature resistance of up to 150℃ and a salt resistance of 15×10⁻⁶. 4 mg / L, which meets the requirements of reservoir temperature ≤150℃ and salinity ≤15×10 4 The demand for permeable oil recovery technology in low-permeability reservoirs with a concentration of mg / L.

[0233] The above is a detailed description of the embodiments, but it is not intended to limit the technical solutions of the present invention. Those skilled in the art should understand that any modifications, partial substitutions, and variations can be made to the above embodiments within the scope of the present invention, and all such modifications and variations should be covered within the scope of the present invention.

Claims

1. A temperature- and salt-resistant permeabilizing agent, characterized in that, The temperature- and salt-resistant penetrant comprises: geminate betaine surfactant and water; it also includes one or two of nonionic surfactant and small molecule alcohol; The structural formula of the described geminate betaine surfactant is: Wherein, R is a chain saturated alkane of C12~C16; The preparation method of the geminate betaine surfactant includes: synthesizing a tetramethyl diamine intermediate by reacting p-phenylenediamine with formaldehyde and formic acid via a Mannich reaction; the intermediate is then reacted with α-bromocarboxylic acid under alkaline conditions to generate the intermediate; the α-bromocarboxylic acid has the general formula RBrCHCOOH, where R is a C12~C16 chain saturated alkane. The mass ratio of the geminate surfactant, nonionic surfactant, and small molecule alcohol is (0.1~0.5):(0.1~0.3):(0.1~0.2).

2. The temperature- and salt-resistant permeation agent according to claim 1, characterized in that, The nonionic surfactant is a C8~C10 alkyl alcohol polyoxyethylene ether.

3. The temperature- and salt-resistant permeation agent according to claim 1, characterized in that, The small molecule alcohol is a C2-C6 monohydric or dihydric alcohol.

4. The temperature- and salt-resistant permeation agent according to claim 1, characterized in that, In the aforementioned temperature- and salt-resistant permeation agent, the mass percentage of the geminate betaine surfactant is 0.1-0.5‰.

5. The temperature- and salt-resistant permeation agent according to claim 1, characterized in that, The preparation method of the temperature- and salt-resistant penetrant includes the preparation step of the geminate betaine surfactant, and the step of mixing the nonionic surfactant, the small molecule alcohol and water.

6. The temperature- and salt-resistant permeation agent according to claim 5, characterized in that, The synthesis of the tetramethyl ditertiary amine intermediate was carried out at a temperature of 50-80°C for 8-48 hours.

7. The temperature- and salt-resistant permeation agent according to claim 6, characterized in that, The molar ratio of p-phenylenediamine, formaldehyde, and formic acid is (1~1.1):(2~2.2):(2.1~2.2).

8. The temperature- and salt-resistant permeation agent according to claim 7, characterized in that, The intermediate is then reacted with α-bromocarboxylic acid at a temperature of 50-100°C for 8-48 hours and at a pH of 8-10.

9. The temperature- and salt-resistant permeation agent according to claim 8, characterized in that, The molar ratio of p-phenylenediamine to α-bromocarboxylic acid is (1~1.1):(2~2.5).

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