Use of complexing composition in high temperature and high salt oil reservoir crude oil recovery

Abstract

This invention belongs to the field of petroleum extraction technology and discloses the application of a compound composition in the recovery of crude oil from high-temperature and high-salinity oil reservoirs. The compound composition comprises, by mass percentage, the following components: 0.01~0.3wt% of arylalkylamide betaine surfactant and alkyl polyoxypropylene polyoxyethylene ether carboxylate, with the remainder being water. The oil displacement compound composition of this invention is effective at temperatures of 80~130℃ and formation water with a total salinity of (9~27)×10⁻⁶. 4 mg / L, calcium and magnesium ion concentration (0.3~1.5)×10 4 It can remain stable for a long time under conditions of mg / L, and after aging for 90 days, the solution remains clear and transparent without precipitation. The surfactant-based oil displacement compound composition of the present invention can achieve an interfacial tension of 10 under high temperature and high salinity conditions. ‑3 ~10 ‑4 With an efficiency on the order of mN / m, the oil washing efficiency can reach over 70%, increasing the recovery rate by more than 10 percentage points. It is suitable for high-temperature and high-salinity reservoirs in tertiary oil recovery.

Description

Technical Field

[0001] This invention belongs to the field of petroleum extraction technology, specifically relating to the application of a compound composition in crude oil recovery from high-temperature and high-salinity oil reservoirs, and is particularly suitable for tertiary oil recovery operations in high-temperature and high-salinity oil reservoirs. Background Technology

[0002] For high-temperature and high-salinity oil reservoirs, such as those with formation temperatures of 115-130℃ and total formation water salinity reaching 15×10⁻⁶, 4 The concentration of calcium and magnesium ions was above mg / L, reaching as high as 9.0 × 10 mg / L. 3 mg / L. Harsh reservoir conditions place extremely high demands on the temperature and salt resistance, stability, and oil displacement efficiency of the oil displacement system.

[0003] Chemical flooding is one of the core technologies for improving tertiary oil recovery, mainly including polymer flooding, alkaline flooding, surfactant flooding, and combined flooding. However, traditional flooding systems exhibit numerous problems under extreme conditions: polymers in polymer flooding are prone to thermal degradation and salt sensitivity, resulting in a sharp decrease in solubility. Alkaline flooding reacts with formation water to form scale, clogging pore channels and corroding equipment. Surfactant flooding has become the most promising technology for improving high-temperature and high-salinity reservoirs due to its ability to effectively reduce oil-water interfacial tension and alter rock wettability to achieve efficient stripping of residual oil. However, conventional surfactant flooding systems suffer from insufficient temperature and salt resistance, limited interfacial activity, and poor synergistic effects. They are prone to precipitation or loss of activity in high-temperature and high-salinity environments, making them unsuitable for harsh reservoir conditions.

[0004] To address the aforementioned challenges, researchers have developed a series of surfactant systems suitable for high-temperature and high-salinity conditions, and related technical solutions and patents have been successively disclosed. However, many technical bottlenecks still exist. For example, Chinese patent application CN202511349611.1 discloses an oil displacement composition composed of a nitrogen-containing surfactant and a sulfur-containing surfactant, which can achieve oil displacement when the total salinity is ≤25×10⁻⁶. 4 mg / L, calcium and magnesium ions ≤2.5×10 4 It can exist stably under conditions of mg / L, with an interfacial tension of up to 10. -2 With a wash-off efficiency on the order of mN / m and exceeding 80%, this type of system relies on the synergistic effect of cationic nitrogen-containing components such as quaternary ammonium salts and pyridinium salts with sulfur-containing components such as sulfates and sulfonates. Its potential for improving interfacial activity is limited, and cationic components are prone to strong adsorption on rock surfaces, resulting in significant loss of the oil displacement agent and reducing the system's migration capacity and oil displacement efficiency. Furthermore, this system only achieves 10... -2 The interfacial tension at the mN / m level has not yet reached the level of ultra-low interfacial tension, and its ability to remove residual oil from micropores and fissures in the reservoir is insufficient.

[0005] Chinese patent application CN201911174244.0 discloses an in-situ emulsification and thickening system composed of nonionic-anionic nonionic surfactants and nanomaterials. Although it can achieve balanced displacement, it relies on special nanomaterials such as γ-aminopropyltriethoxysilane-modified carbon nanotubes. The preparation process of such materials is complex and costly, and the injection pressure is prone to sudden increase due to rock pore blockage during the injection process. The upper limit of the applicable injection water salinity is 22 × 10⁻⁶. 4 The calcium ion concentration is 5000 mg / L, which does not meet the requirement of a calcium and magnesium ion concentration of 10 mg / L. 4 The requirement for mg / L of extremely high salinity reservoirs.

[0006] Chinese patent application CN202011157474.9 discloses a complex system of fatty acid alkanolamides, betaine compounds, alkylbenzene sulfonates, and low-molecular-weight alcohols. This system enhances salt and divalent cation resistance through the synergistic effect of multiple functional groups. However, its temperature and salt tolerance are limited; when the mineralization exceeds 5 × 10⁻⁶, the resistance decreases. 4 When the calcium and magnesium content is higher than 4000 mg / L, the oil displacement agent may precipitate and cannot be used in oil fields with high salinity and high hardness. In addition, the presence of low molecular weight alcohols in the system may affect formation stability, and long-term injection may easily cause potential formation damage.

[0007] To address the adaptation requirements of ultra-high temperature, high salinity, and high hardness oil reservoirs, Chinese patent application CN201710088994.0 discloses an oil displacement system for such reservoirs. This system is composed of 0.3–0.5 wt% fatty alcohol polyoxyethylene ether carboxylate and 0.3–0.5 wt% sulfopropyl betaine, and is suitable for applications at 130℃ and a total salinity of 25 × 10⁻⁶. 4 Under reservoir conditions with a concentration of 10,000 mg / L calcium and magnesium ions and a calcium-magnesium ion concentration of 10,000 mg / L, the oil-water interfacial tension can be reduced to 10 under alkaline-free conditions. -3 The surfactants used are on the order of mN / m, and all are industrially produced, resulting in relatively low costs. This achieves a balance between temperature and salt resistance and engineering applicability. However, the adaptability to reservoirs with higher calcium and magnesium ion concentrations (>10000 mg / L) needs further optimization.

[0008] Chinese patent application CN202511030008.7 discloses a PPO / PEO block Gemini extended surfactant, which achieves temperature and salt resistance through a single Gemini structure and PPO / PEO block design, and can be used without compounding. However, this monomer requires a complex four-step synthesis (propoxylation / ethoxylation → linker preparation → esterification → sulfonation), with harsh process conditions (negative pressure, high temperature catalysis), high cost for large-scale production, and is only suitable for single high-salt NaCl environments. It lacks stability data under high calcium and magnesium ion conditions, does not involve anti-adsorption design, and has limited applicability in heterogeneous reservoirs.

[0009] In view of the above-mentioned deficiencies, this application is filed. Summary of the Invention

[0010] To address the problems of insufficient temperature and salt resistance, unstable interfacial activity, large adsorption loss, or high engineering application cost of existing surfactant-based oil displacement systems in high-temperature and high-salinity reservoirs, this invention provides a compound composition suitable for oil displacement in high-temperature and high-salinity reservoirs.

[0011] The application of a compound composition in the recovery of crude oil from high-temperature and high-salinity oil reservoirs, wherein the compound composition comprises arylalkylamide betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylate, wherein the mass ratio of arylalkylamide betaine to alkyl polyoxypropylene polyoxyethylene ether carboxylate is (1~30):(1~20).

[0012] The characteristics of high-temperature and high-salinity oil reservoirs are: temperatures between 80 and 130°C, and total formation water salinity of (9 to 27) × 10⁻⁶. 4 mg / L, valence ion content greater than 0.1×10 4 mg / L.

[0013] Through the synergistic effect of arylalkylamide betaine surfactant and alkyl polyoxypropylene polyoxyethylene ether carboxylate, it can maintain long-term stability under high temperature and high salinity conditions and at a low concentration, achieving ultra-low interfacial tension, high oil washing efficiency, and effectively improving the recovery rate of high temperature and high salinity oil reservoirs. Attached Figure Description

[0014] Figure 1 The interfacial tension of the compound composition solutions prepared in different mass ratios of octadecylarylamide hydroxysulfonyl betaine / alkyl polyoxypropylene polyoxyethylene ether sodium carboxylate in Examples 1-9; Figure 2 The interfacial tension of the compound composition solutions prepared at different mass ratios of ordinary betaine / alkyl polyoxypropylene polyoxyethylene ether carboxylate in Comparative Example 1; Figure 3 The interfacial tension of the compound composition solutions prepared at different mass ratios of octadecylarylamide hydroxysulfonyl betaine / alkyl polyoxyethylene polyoxypropylene ether sodium carboxylate in Comparative Example 1; Figure 4 The interfacial tension of different concentrations of compound solutions of octadecyl arylamide hydroxysulfonyl betaine: alkyl polyoxyethylene polyoxypropylene ether sodium carboxylate (7:3) prepared in Experimental Example 1 under different aging days; Figure 5 The washing efficiency of different concentrations of compound solutions prepared with octadecyl arylamide hydroxysulfonyl betaine: alkyl polyoxyethylene polyoxypropylene ether sodium carboxylate (7:3) in Experimental Example 3; Figure 6 The emulsification water separation rate of different concentrations of compound solutions prepared in Experimental Example 2 with octadecyl arylamide hydroxysulfonyl betaine: alkyl polyoxyethylene polyoxypropylene ether sodium carboxylate (7:3) is given. Detailed Implementation

[0015] The following is a more detailed description of the compound composition for crude oil in high-temperature, high-salinity oil reservoirs according to the present invention. This description does not limit the scope of protection of this application, which is defined by the claims. Certain specific details disclosed provide a comprehensive understanding of the various disclosed embodiments. However, those skilled in the art will recognize that embodiments can be implemented using other materials, etc., without employing one or more of these specific details.

[0016] Unless the context otherwise requires, the terms “comprising” and “including” in the specification and claims shall be understood as open-ended and inclusive, meaning “including, but not limited to”.

[0017] The terms "implementation," "an implementation," "another implementation," or "certain implementations" used in this specification refer to specific features, structures, or characteristics described in relation to the implementation, which are included in at least one implementation. Therefore, "implementation," "an implementation," "another implementation," or "certain implementations" do not necessarily all refer to the same implementation. Furthermore, specific features, structures, or characteristics can be combined in any way within one or more implementations. Each feature disclosed in this specification can be replaced by any alternative feature that provides the same, equivalent, or similar purpose. Therefore, unless otherwise specified, the disclosed features are merely general examples of equivalent or similar features.

[0018] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. Unless otherwise stated, all percentages, ratios, proportions, or parts are by weight. The numerical ranges in this application include point values ​​at both ends.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as are familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0020] The term "mineralization" in this application refers to the soluble salts (such as Ca) contained in a unit volume of water. 2+ Mg 2+ Na + K+ HCO3 - Cl - The total mass of (etc.), commonly expressed in mg / L or g / L (1 g / L = 1000 mg / L).

[0021] Although betaine-based single surfactant systems possess certain temperature and salt resistance and can prevent formation scaling under alkali-free conditions, the interfacial activity of single betaine systems is relatively weak, making it difficult to achieve ultra-low oil-water interfacial tension. They need to be compounded with other surfactants for synergistic effects. Furthermore, conventional alkyl betaine has a simple hydrophobic chain structure, resulting in poor compatibility with crude oil under high temperature and high salt conditions, and limited wettability reversal effect.

[0022] Arylalkyl amide betaine, as an amphoteric surfactant, combines the salt tolerance of a cationic head group with the stability of an amide bond. Its aryl structure enhances the hydrophobic interaction with crude oil, improving interfacial activity. Short-chain extended alkyl polyoxypropylene polyoxyethylene ether carboxylates reduce molecular aggregation through their short-chain hydrophobic groups, and the steric hindrance effect of the polyether chain inhibits the binding of calcium and magnesium ions to carboxyl groups, improving hard water resistance. The inventors discovered that the combination of these two surfactants synergistically enhances solubility, inhibits adsorption, and reduces the interfacial tension between water and oil.

[0023] On the one hand, there is the application of a compound composition in the recovery of crude oil from high-temperature and high-salinity oil reservoirs. The compound composition includes arylalkylamide betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylate, wherein the mass ratio of arylalkylamide betaine to alkyl polyoxypropylene polyoxyethylene ether carboxylate is (1~30):(1~20).

[0024] Optionally, the mass ratio of arylalkylamide betaine to alkyl polyoxypropylene polyoxyethylene ether carboxylate is 1:9 to 9:1, for example: the mass ratio of arylalkylamide betaine to alkyl polyoxypropylene polyoxyethylene ether carboxylate is 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8 or 1:9.

[0025] Preferably, the mass ratio of arylalkylamide betaine to alkyl polyoxypropylene polyoxyethylene ether carboxylate is 1:1 to 5:2.

[0026] A more preferred formulation has an arylalkylamide betaine to alkyl polyoxypropylene polyoxyethylene ether carboxylate mass ratio of (1.5-2.5):1, for example, an arylalkylamide betaine to alkyl polyoxypropylene polyoxyethylene ether carboxylate mass ratio of 7:3 or 6:4. Within this range, the formulation exhibits superior interfacial activity in high-temperature, high-salt systems.

[0027] In some embodiments, the compound composition contains water, wherein the total mass percentage of arylalkyl amide betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylate is 0.01 to 0.3 wt%, for example, the total mass percentage of surfactant in the compound composition is 0.01 wt%, 0.02 wt%, 0.05 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, or 0.3 wt%.

[0028] Alternatively, the total mass percentage of arylalkylamide betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylate in the compound composition is 0.035~0.25 wt%.

[0029] Optionally, the total mass percentage of arylalkylamide betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylate in the compound composition is 0.05~0.3wt%, preferably, the total mass percentage of arylalkylamide betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylate is 0.1~0.3wt%.

[0030] In addition to the arylalkylamide betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylate mentioned above, the remainder of the compound composition is water.

[0031] The water is high-temperature, high-salinity formation water from an oil reservoir, with a total salinity greater than 1×10⁻⁶. 4 mg / L, the content of divalent ions is greater than 0.1×10 4 mg / L.

[0032] Optional, mineralization degree (9~27) × 10 4 mg / L.

[0033] Divalent ions include magnesium ions and calcium ions, with a calcium-magnesium ion concentration of (0.3~1.5)×10⁻⁶. 4 mg / L.

[0034] Optionally, the properties of the compound composition for use in high-temperature, high-salinity reservoirs include: formation water temperature ≤130℃ (e.g., 80-130℃), and total salinity ≤27×10⁻⁶. 4 mg / L ((9~27)×10 4 (mg / L), calcium and magnesium ion concentration ≤1.5×10 4 mg / L (e.g., (0.3~1.5)×10 4 High-temperature, high-salinity oil reservoirs (mg / L).

[0035] Optionally, the formation water temperature of high-temperature, high-salinity oil reservoirs should be approximately 130℃, with a total salinity of (15~20)×10⁻⁶. 4 (mg / L), calcium and magnesium ion concentrations of (0.5~1.0)×10 4 mg / L.

[0036] The oil displacement process essentially involves injecting fluids to alter the physicochemical conditions of the reservoir, overcoming resistances such as capillary forces and viscous forces, and achieving effective displacement and recovery of the oil phase in porous media. This requires the oil displacement system to significantly reduce oil-water interfacial tension, improve mobility ratio, expand swept volume, and possess good oil washing and rock wettability alteration capabilities. Simultaneously, it must be compatible and stable with formation fluids and rocks, without significant stratification, precipitation, or adsorption losses.

[0037] By using a specific ratio of the aforementioned compound system of arylalkylamide betaine and polyoxypropylene polyoxyethylene ether carboxylate, an aromatic ring structure is introduced into the hydrophobic end of betaine and compounded with polyoxypropylene polyoxyethylene ether carboxylate. The steric hindrance effect of the aromatic ring enhances the temperature and salt resistance of betaine, while the polyoxypropylene polyoxyethylene ether carboxylate optimizes the hydrophilic-lipophilic balance of the compound system. This results in an oil displacement system with excellent temperature and salt resistance, outstanding interfacial activity, and high oil washing efficiency. This system can efficiently initiate and displace residual oil in high-temperature, high-salt reservoirs, ultimately improving oil recovery.

[0038] Therefore, existing oil displacement systems suffer from limitations in temperature, salt, and hardness resistance in high-temperature and high-salinity reservoirs, insufficient interfacial activity and oil washing efficiency, high adsorption losses, high synthesis costs, and poor engineering applicability. Different reservoir conditions, such as temperature, the types and contents of metal ions, all affect the performance of the oil displacement system. The compound composition provided in this application exhibits good performance in high-temperature and high-salinity reservoirs (temperature 80~130℃, total salinity (9~27)×10⁻⁶). 4 mg / L, calcium and magnesium ion concentration (0.3~1.5) × 10 4 It exists stably under conditions of mg / L without precipitation, while achieving ultra-low oil-water interfacial tension, low adsorption loss and high oil washing efficiency.

[0039] The general structural formula of arylalkylamide betaine is as follows:

[0040] a and b are positive integers from 2 to 10.

[0041] In the possible solutions, a and b are positive integers from 2 to 10, and a + b = 5 to 19, with a + b = 15 being the preferred value. Further optimization is to find a = 7 and b = 8 or a = 8 and b = 7; o=1~10, 3 is preferred; Ar is phenyl, methylphenyl, ethylphenyl or dimethylphenyl, preferably 3,5-dimethylphenyl; R1 and R2 are H or C1~C4 alkyl groups, preferably methyl; X --CH(OH)CH2SO3 - (hydroxysulfonyl) or -COO - (Carboxyl group), preferably hydroxysulfonyl group; That is, in arylalkyl amide betaine, the hydrophobic chain (alkyl) is a C12~C23 alkyl, preferably a C18 straight-chain alkyl.

[0042] In a preferred embodiment, the structural formula of octadecylarylamide hydroxysulfonate in the compound composition is as follows:

[0043] The structural formula of polyoxypropylene polyoxyethylene ether carboxylate is as follows: RO-(CH2CH (CH3) O) m -(CH2CH2O) n -CH2COOM.

[0044] R represents an alkyl group, and M represents an alkaline metal element. m represents the sum of oxypropylene ether units, and n represents the sum of oxyethylene ether units. m and n are key structural parameters that affect its temperature and salt resistance, interfacial activity, and washing efficiency. m mainly provides hydrophobicity and temperature resistance, while n mainly provides water solubility and salt stability.

[0045] M can be sodium or potassium, preferably sodium ions, which can effectively avoid precipitation caused by hydrolysis or reaction of metal ions and ensure the stability of the system.

[0046] In some embodiments, R is a straight-chain alkyl or a branched alkyl; preferably, R is a C8-C10 straight-chain alkyl.

[0047] In the simplified structural formula of polyoxypropylene polyoxyethylene ether carboxylate, m is 10~15 and n is 5~15; preferably m is 10 and n is 5.

[0048] In alkyl polyoxypropylene polyoxyethylene ether carboxylate, R is a C8 straight-chain alkyl group, m is 10, and n is 5.

[0049] In particular, arylalkyl amide betaine is selected from octadecylaryl amide hydroxysulfonyl betaine, and alkyl polyoxypropylene polyoxyethylene ether carboxylate is selected from short carbon chain C8PO. 10 EO5C carboxylate, when combined with the other components, is highly compatible with the hydrophobic components of crude oil. Combined with the steric hindrance of the aryl group, it can effectively resist dissociation in high-temperature and high-salt environments. It precisely balances hydrophilic and lipophilic properties, inhibits the binding of calcium and magnesium ions with carboxyl groups, enhances the resistance to hard water, and ensures that the system is stable and free from precipitation under extreme working conditions.

[0050] The aryl structure of octadecyl aryl amide hydroxysulfonate betaine forms a π-π interaction with the aromatic components of crude oil, resulting in a short carbon chain C8PO4. 10The polyether chains of EO5C carboxylate diffuse and spread rapidly. The mixed adsorption film of the two compounds repels each other, resulting in a denser and more stable film, and synergistically reduces the interfacial tension to 10. -3 With a strength below mN / m, it significantly reduces capillary resistance during the oil displacement process, providing power for the start-up of residual oil.

[0051] The amide bond of octadecylarylamide hydroxysulfonate forms a hydrogen bond with the hydroxyl group of the rock, reducing adsorption. The short carbon chain C8PO 10 The steric hindrance of the polyether chain of EO5C carboxylate forms a protective film and prevents excessive adsorption of betaine, thus achieving low adsorption loss in a synergistic manner. The strong hydrophobic effect of the long carbon chain of octadecyl arylamide hydroxysulfonate betaine complements the penetrating emulsification effect of the short carbon chain of polyether, effectively stripping and displacing residual oil and significantly improving the oil recovery rate.

[0052] In solutions of alkyl polyoxypropylene polyoxyethylene ether carboxylates with short carbon chains R greater than 10 carbons or n less than 5, and octadecyl aryl amide hydroxysulfonyl betaine, when applied to high-temperature, high-salinity oil reservoirs (e.g., formation temperatures 80-130℃) with a total salinity of (9-27) × 10⁻⁶, [the solution is suitable for applications involving these compounds]. 4 mg / L, calcium and magnesium ion concentration (0.3~1.5) × 10 4 At a concentration of mg / L, the reduction in interfacial tension is small, resulting in a relatively poor effect in stripping and displacing residual oil.

[0053] Preferably, the alkyl polyoxypropylene polyoxyethylene ether carboxylate is a sodium salt, as sodium ions completely avoid the risk of hydrolysis and precipitation. 10 The EO5 chain segment and betaine head group synergistically enhance the resistance to hard water, adjust the HLB value to ensure long-term stability of the system without stratification, reduce the risk of injection blockage, and ensure engineering applicability.

[0054] The arylalkylamide betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylates of this application can be commercially available products; they can also be prepared in-house using any existing method that can produce the corresponding substances. One such method is listed below.

[0055] The preparation method of octadecylarylamide hydroxysulfonate betaine refers to Chinese patent application publication number CN103641750A, which specifically includes the following steps: Amide reaction: Aryl alkyl fatty acid methyl esters were reacted with N,N-dimethylpropylenediamine under alkaline catalyst at 120–200 °C, nitrogen protection, and 0.2–0.8 atm pressure for 8–24 hours. The byproduct methanol was removed to obtain the aryl alkyl amide tertiary amine intermediate. The synthetic route is as follows:

[0056] Quaternization reaction: The obtained arylalkylamide tertiary amine was reacted with sodium 3-chloro-2-hydroxypropanesulfonate in methanol solvent at 90–130 °C and 0.3–0.6 MPa for 6–12 hours. After solvent removal, extraction, desalting, and drying, the arylalkylamide hydroxysulfonate was obtained. The synthetic route is as follows:

[0057] The preparation method of alkyl polyoxypropylene polyoxyethylene ether carboxylates refers to Chinese patent application publication number CN102485771A, which specifically includes the following steps: Etherification reaction: Using C8 fatty alcohol as a starting agent, under alkaline catalyst and nitrogen protection, at 130–170 °C and 0.2–0.5 MPa, propylene oxide (PO) and ethylene oxide (EO) are sequentially introduced in predetermined proportions to carry out the addition reaction. After the reaction pressure is constant and aging is completed, the catalyst is neutralized and low-boiling-point substances are removed to obtain the PO / EO block alkyl polyoxypropylene polyoxyethylene ether intermediate;

[0058] Alkalization reaction: The obtained polyether intermediate is mixed with excess sodium hydroxide and reacted at 100~110℃ under nitrogen protection. The water generated in the reaction is removed by vacuum distillation to fully alkalize the polyether to produce sodium polyether.

[0059] Carboxymethylation reaction: Sodium chloroacetate was added in batches to the sodium polyether salt at 70–100°C, and the reaction was carried out for 6–12 hours. After the reaction was completed, the product was obtained by neutralization, desalting, and drying purification to obtain the target product, sodium alkyl polyoxypropylene polyoxyethylene ether carboxylate.

[0060]

[0061] In the high-temperature, high-salinity oil recovery process of this application, the aromatic ring conjugated structure and steric hindrance effect of the arylalkyl amide hydroxysulfonyl betaine are utilized, combined with the branched modification design of short-chain extended alkyl polyoxypropylene polyoxyethylene ether carboxylate, to effectively resist high-temperature thermal degradation and avoid calcium and magnesium ion complexation and hydrophobic association precipitation. Amide bond modification optimizes the adsorption morphology of betaine on the rock surface, and when combined with alkyl polyoxypropylene polyoxyethylene ether carboxylate (especially C8PO4), it effectively resists high-temperature thermal degradation and avoids calcium and magnesium ion complexation and hydrophobic association precipitation. 10The steric hindrance of EO5C significantly reduces irreversible adsorption; simultaneously, the system contains no added cationic surfactants, avoiding reagent loss and slug integrity disruption caused by cationic adsorption, resulting in a wider sweep volume in heterogeneous reservoirs. The aryl structure of the aryl alkyl amide hydroxysulfonate betaine exhibits similar compatibility with aromatic hydrocarbons and gums in crude oil, enabling rapid reversal of rock wetting from oily to strongly watery, thus providing more targeted oil washing. The compound system described in this application demonstrates good compatibility with various types of crude oil, including paraffinic, naphthenic, and high-asphaltite crudes.

[0062] On the other hand, the arylalkylamide hydroxysulfonate betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylate in the compound composition of this application are stored separately from water. That is, when in use, the surfactants, such as arylalkylamide hydroxysulfonate betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylate, are mixed with water to form a solution. The water here can be formation water from high-temperature, high-salinity oil reservoirs or simulated formation water.

[0063] In one aspect, the preparation method of the above-mentioned compound composition of this application includes: mixing arylalkylamide hydroxysulfonamide and alkyl polyoxypropylene polyoxyethylene ether carboxylate, then mixing with water, and stirring the mixture until it becomes clear to obtain the compound composition. The concentration of the compound is 0.05~0.3wt%.

[0064] The oil displacement compound composition of the present invention is stably applicable to formation temperatures ≤130℃ (e.g., 80-130℃) and total salinity ≤27×10⁻⁶. 4 mg / L (e.g. (9~27)×10 4 (mg / L), calcium and magnesium ion concentration ≤1.5×10 4 mg / L (e.g., (0.3~1.5)×10 4 In high-temperature, high-salinity oil reservoirs (mg / L), under alkaline-free conditions, a certain ratio of compounded components can reduce the oil-water interfacial tension to 10. -4 ~10 -3 The ultra-low mN / m level avoids serious damage to the oil layer and equipment caused by alkaline scaling; and after aging for more than 60 days under high temperature and high salt conditions at 130℃, the ability to reduce interfacial tension decreases only slightly, the oil washing efficiency can reach more than 80%, and the ability to remove residual oil from micropores is significantly better than existing technologies.

[0065] Furthermore, arylalkylamide hydroxysulfonyl betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylate are readily miscible with formation water at room temperature, making the preparation process simple. It also exhibits good compatibility with existing oilfield injection pipelines, requiring no additional equipment modifications, and is suitable for large-scale field application. It possesses multiple advantages, including low cost, high economic efficiency, high oil displacement efficiency, and good environmental performance.

[0066] The application of the compound composition of the present invention in crude oil recovery from high-temperature and high-salinity oil reservoirs is further illustrated below with specific embodiments. All substances used in the following embodiments are chemically pure standards.

[0067] Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention were all purchased commercially.

[0068] In the following examples, comparative examples, and experimental cases, the water used was simulated formation water with a total salinity of 18 × 10⁻⁶. 4 mg / L, Ca 2+ Mg 2+ Ion concentration 8×10 3 mg / L, reservoir temperature 130℃, crude oil used was dehydrated and degassed crude oil from Qinghai Oilfield: surface crude oil density 0.8349 g / cm³ 3 Low viscosity (15.1 mPa·s).

[0069] The following examples and comparative examples refer to the following methods for evaluating the solubility and testing the interfacial tension of the compound compositions: Solubility test: Prepare solutions of different concentrations or different surfactants using simulated water at room temperature, and observe the state of the surfactant solutions.

[0070] Interfacial tension test: The interfacial tension was tested using the CNGTX701 high-temperature rotating drop interfacial tension meter with the rotating drop method. The test temperature was 130℃ and the rotation speed was 5000r / min. The results are recorded in the table or in the corresponding examples or comparative examples. Example 1

[0071] Preparation of compound composition The method includes: preparing the above-mentioned octadecyl arylamide hydroxysulfonyl betaine surfactant (denoted as component A, which is prepared according to the method of Example 1 of patent application publication number CN103641750A) and alkyl polyoxypropylene polyoxyethylene ether carboxylate surfactant (denoted as component B, with the structural formula C8PO) 10 EO5C was prepared according to the method of Example 1 in patent application publication number CN102485771A, with corresponding adjustments to the raw material fatty alcohol being an 8-carbon chain linear fatty alcohol, and the ratio of propylene oxide and ethylene oxide. The alkyl group was a C8 linear alkyl group, the summation number m of the oxypropylene ether units was 10, the summation number of the oxyethylene ether units was 5, and C represented -CH2COONa). The mixture was prepared at a mass ratio of 7:3, then mixed with simulated formation water at room temperature, and stirred continuously for 30 minutes until the solution was homogeneous and clear, thus preparing a 0.3 wt% compound composition solution.

[0072] The interfacial tension of the above-mentioned compound composition was tested at a temperature of 130°C, and the test results are shown in Table 1.

[0073] Examples 2-9 Examples 2-9 describe the preparation of compound compositions, including their composition, solution concentration, and method, as described in Example 1, except that octadecyl arylamide hydroxysulfonyl betaine and sodium alkyl polyoxypropylene polyoxyethylene ether carboxylate (C8PO4) are used. 10 The mass ratios of EO5C and other components differ. Interfacial tension tests were performed on these components, and the results are shown in Table 1. Figure 1 As shown.

[0074] Table 1

[0075] As shown in Table 1, no precipitate was formed in the solutions of the compound compositions with different mass ratios, and the interfacial tension was within 1.2 × 10⁻⁶. -3 ~9.8×10 -2 mN / m. When the mass ratio of the two is 7:3 and 6:4, the interfacial tension can reach 10. -3 It exhibits the order of mN / m and has the best interfacial activity.

[0076] Examples 10-13 Examples 10-13 describe the preparation of the compound combinations using the same composition and method as in Example 1, except that the concentration of the compound combination solution is different from that in Example 1. Interfacial tension tests were also performed on the compound combinations, and the results are shown in Table 2.

[0077] Examples 14-17 Examples 14-17 describe the preparation of the compound combinations and the methods used in Example 2, except that the concentration of the compound combination solution is different from that in Example 2, and the interfacial tension is tested. The test results are shown in Table 2.

[0078] Table 2

[0079] Table 2 shows that the oil displacement compound composed of octadecyl aryl amide hydroxysulfonyl betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylate surfactant in a mass ratio of 7:3, with a content of 0.05~0.3wt%, has an interfacial tension of 2.5×10⁻⁶. -3 ~1.2×10 -3 Between mN / m.

[0080] Comparative Example 1 This comparative example uses N,N-dimethyl-octadecyl-hydroxypropyl sulfonate betaine (hereinafter referred to as "common betaine") and sodium alkyl polyoxypropylene polyoxyethylene ether carboxylate (C8PO4). 10 EO5C was compounded and the interfacial tension performance at different mass ratios was investigated.

[0081] Simulated formation water (total mineralization 18×10⁻⁶) was used. 4 mg / L, Ca 2+ Mg 2+ Ion concentration 8×10 3 (mg / L) were used to prepare ordinary betaine and C8PO4 respectively. 10 Compound compositions with EO5C mass ratios of 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, and 1:9 were prepared, and the concentration of the compound composition solution was controlled at 0.3 wt%. The mixture was stirred thoroughly until completely dissolved and then set aside for later use.

[0082] At a high temperature of 130℃, the interfacial tension of the compound solutions in various proportions with crude oil was tested. The test results are shown in Table 3. Figure 2 As shown: Table 3

[0083] The test results of Comparative Example 1 showed that N,N-dimethyl-octadecyl-hydroxypropyl sulfonate betaine and C8PO 10 In the EO5C compound system, under high temperature and high salinity conditions of 130℃, the oil-water interfacial tension of all ratios was only 10. -2 The mN / m level is insufficient to reach 10. -2 The interfacial tension is extremely low, below mN / m, and the interfacial tension at the optimal ratio (7:3) is still much higher than that of the arylalkylamide hydroxysulfonate betaine compound system of this invention (the preferred system of this invention can stably maintain an interfacial tension of 10 at 130°C). -3 (mN / m level).

[0084] This result fully demonstrates that ordinary alkyl betaines, due to the lack of aryl and amide bonds at their hydrophobic ends, exhibit significantly insufficient compatibility, interfacial activity, and temperature resistance with crude oil, even when combined with C8PO4. 10 Even with EO5C compounding, the ultra-low interfacial tension and excellent oil displacement performance described in this invention cannot be achieved, further highlighting the advantages of the compound composition of arylalkyl amide hydroxysulfonyl betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylate for crude oil extraction in high-temperature and high-salinity oil reservoirs.

[0085] Comparative Example 2 This comparative example uses sodium alkyl polyoxyethylene polyoxypropylene ether carboxylate (C8EO5PO) 10 C) The interfacial tension properties were investigated by combining it with octadecylarylamide hydroxysulfonate at different mass ratios.

[0086] Octadecylarylamide hydroxysulfonyl betaine and sodium alkyl polyoxyethylene polyoxypropylene ether carboxylate (R is a C8 straight-chain alkyl group, similar to the C8PO group in the embodiments of this invention) were prepared separately. 10Compositions with the same PO and EO summation numbers (only the block order is reversed) in mass ratios of 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, and 1:9.

[0087] The same simulated formation water as in the example was used to prepare the compound solution, with the total mass fraction controlled at 0.3 wt%. The solution was stirred thoroughly until completely dissolved and set aside.

[0088] At a high temperature of 130℃, the interfacial tension of the compound solutions in various proportions with crude oil was tested. The test results are shown in Table 4. Figure 3 As shown: Table 4

[0089] Comparative Example 2 test results show that at a high temperature of 130℃ and a total mineralization of 18×10⁻⁶, 4 mg / L, Ca 2+ Mg 2+ Ion concentration 8×10 3 Under harsh reservoir conditions of mg / L, octadecyl arylamide hydroxysulfonyl betaine and sodium alkyl polyoxyethylene polyoxypropylene ether carboxylate C8EO5PO 10 In the C-based compound system, the interfacial tension showed a continuous increasing trend with the increase of the proportion of sodium alkyl polyoxyethylene polyoxypropylene ether carboxylate, reaching a maximum of 3.8 mN / m. Even in the optimal ratio with the highest proportion of betaine (9:1), the interfacial tension was only 8.3 × 10⁻⁶ mN / m. -2 mN / m, far from reaching 10 -2 Ultra-low interfacial tension requirements below mN / m.

[0090] The results fully confirm that the PO-addition followed by EO addition (alkyl polyoxypropylene polyoxyethylene ether carboxylate) structure selected in this invention, with the PO segment adjacent to the hydrophobic alkyl group, provides strong steric hindrance and high-temperature resistance, effectively shielding calcium and magnesium ions and preventing the combination of carboxyl groups and divalent ions. Simultaneously, it enables the molecule to form a regular and dense adsorption film at the oil-water interface, achieving synergistic effects with the aryl amide hydroxysulfonate betaine, and can stably maintain 10 under the same conditions. -3 The interfacial tension is extremely low, reaching mN / m; while conventional EO-addition followed by PO structures, with the EO segment adjacent to the hydrophobic end, exhibits poor temperature resistance, weak hard water resistance, and is prone to chain breakage and disordered molecular arrangement under high temperature and high salt conditions, making it unable to form a synergistic effect with aryl amide betaine and only achieving 10. -2 The interfacial tension of mN / m is insufficient to meet the oil displacement requirements of high-temperature and high-salinity reservoirs.

[0091] Comparative Example 3 Take 49.85g of simulated formation water and place it in a stirrer. Under the conditions of room temperature 25℃ and rotation speed 4000r / min, add 0.15g of octadecylarylamide hydroxysulfonate betaine and stir for 30min until the solution is clear and transparent and free of suspended particles. This gives you the prepared 0.3wt% surfactant solution.

[0092] The prepared surfactant solution was a homogeneous phase with no precipitate formation; its interfacial tension (mN / m) was measured to be 2.0 × 10⁻⁶. -2 .

[0093] Comparative Example 4 Take 49.85g of simulated formation water and place it in a stirrer. Under the conditions of room temperature 25℃ and a stirring speed of 4000r / min, add 0.15g of sodium alkyl polyoxypropylene polyoxyethylene ether carboxylate (C8PO4). 10 Stir for 30 minutes until the solution is clear and transparent with no suspended particles, and you will get the prepared 0.3wt% surfactant solution.

[0094] The prepared surfactant solution was a homogeneous phase with no precipitate formation; its interfacial tension (mN / m) was measured to be 1.8 × 10⁻⁶. -1 .

[0095] Experimental Example 1 This experimental example examines the aging performance of the compound compositions prepared in Examples 1 and 11-13 for high-temperature, high-salt subsurface oil displacement. The compound composition solutions prepared in each embodiment were placed in an oven at 130°C. Periodically, they were removed and the interfacial tension at the corresponding temperatures was tested using a CNGTX701 high-temperature rotating drop interfacial tensiometer via the rotating drop method to evaluate their aging performance. The experimental results are shown in Table 5 and... Figure 4 As shown.

[0096] Table 5

[0097] As shown in Table 5, solutions of the compound composition for oil displacement with concentrations of 0.05wt%, 0.1wt%, 0.2wt%, and 0.3wt% remained clear and transparent after aging in an oven at 130℃ for 90 days (d), without precipitation, stratification, or oil floating. The oil-water interfacial tension remained stable; except for a slight increase in the interfacial tension of the 0.05wt% concentration group, the interfacial tension of the 0.1wt%, 0.2wt%, and 0.3wt% concentration groups did not change significantly and remained within 10. -3 The magnitude indicates that the compound composition of the present invention has excellent long-term stability under high temperature and high salt conditions.

[0098] Experimental Example 2 Study on the emulsifying properties of compounded compositions for oil displacement under high temperature and high salinity conditions Unaged solutions of the high-temperature, high-salt oil displacement compound compositions prepared in Examples 1 and 11-13 were added to sealable glass containers at a volume ratio of 5:5, with 10 ml of each sample. The containers were placed in a 130°C oven for 30 minutes, then removed and vigorously shaken up and down 100 times to ensure thorough mixing of the oil displacement compound composition and crude oil. The containers were then returned to the oven. Periodic photographs were taken to record the water separation at fixed times to evaluate the emulsification performance. The experimental results are shown in Table 6. Figure 6 As shown.

[0099] Table 6

[0100] As can be seen from Table 6, solutions of the oil displacement compound composition with contents of 0.05wt%, 0.1wt%, 0.2wt%, and 0.3wt% showed almost no water separation within 120 minutes, with a water separation rate of <5%. This indicates that the oil displacement compound composition of the present invention has a good emulsifying effect and the oil-water interfacial tension between the oil phase and the water phase is at an ultra-low level, which can effectively emulsify crude oil and facilitate the stripping and displacement of residual oil.

[0101] Experimental Example 3 Performance evaluation of the oil washing properties of the compound composition for oil displacement under high temperature and high salinity conditions Washing rate test: (1) After washing the formation sand, mix it with the crude oil of the target block at a ratio of 4:1 (mass ratio), put it in an oven and age it at a constant temperature of 130℃ for 7 days, stirring once a day to make the oil sand evenly mixed; (2) Weigh 5.000g of the aged oil sand and put it into a 100mL conical flask, weigh it to get m1; (3) Add 0.3wt% 50g of the surfactant solution prepared in Example 1 to the sample in step (2), mix it thoroughly, and let it stand at the reservoir temperature for 48h; 4) Use clean cotton yarn to remove the crude oil floating in the sample solution after step (3) and the crude oil adhering to the bottle wall, and pour out the surfactant solution. Then place the conical flask in a 100℃ oven to dry to constant weight, and obtain m2; (5) Use petroleum ether with a boiling range of 90℃~120℃ to elute the crude oil from the sample in step (2) until the petroleum ether is colorless; (6) Place the conical flask from which the crude oil has been eluted in step (5) in a 120℃ oven to dry to constant weight, and weigh to obtain m3; (7) Calculate the crude oil elution rate according to the following formula:

[0102] In the formula: σ — crude oil elution rate, % m1—Total mass of the conical flask and oil sand before washing, in g; m2 — Mass of the conical flask and oil sand after washing, in grams; m3 — Mass of conical flask and washed formation sand, in grams.

[0103] Oil displacement compound composition solutions with contents of 0.05wt%, 0.1wt%, 0.2wt%, and 0.3wt% were prepared according to Examples 11-13 and Example 1. The oil washing performance of the oil displacement compound compositions was evaluated according to the oil washing test procedure. The experimental results are shown in Table 7. Figure 5 As shown.

[0104] Table 7

[0105] As can be seen from Table 7, when the content of the compound composition for oil displacement in high-temperature and high-salinity reservoirs of the present invention is 0.05~0.3wt%, its oil washing rate is 68~87%; when the content of the compound composition for oil displacement is >0.1wt%, the oil washing rate exceeds 75%, and the oil washing rates of the 0.2wt% and 0.3wt% concentration groups both exceed 80%, indicating that the compound composition for oil displacement in high-temperature and high-salinity reservoirs of the present invention has excellent oil washing performance.

[0106] Experiment Example 4 The oil displacement performance of the compound compositions for high-temperature, high-salt oil displacement prepared in Examples 11-13 and Example 1 was investigated. Consistent with Experiments 1-3, the reservoir temperature was 130℃, and the simulated total formation water salinity was 18×10⁻⁶. 4 mg / L, Ca 2+ Mg 2+ Ion concentration 8×10 3 mg / L; the crude oil used was dehydrated and degassed crude oil from the oilfield, with a surface density of 0.8349 g / cm³. 3 The viscosity is low, 15.1 mPa·s; the core is quartz sandstone with a permeability of 45~55×10⁻⁶ mPa·s. -3 μm 2 Porosity 22~24%.

[0107] Enhanced oil recovery testing method: The test shall be conducted in accordance with the petroleum industry standard SY / T 6424-2014 "Performance Testing Method for Composite Oil Displacement Systems". Specific steps are as follows: ① Core pretreatment: After drilling, oil washing, and drying, the air permeability and pore volume are measured; ②Saturated fluid: Simulated formation water was saturated at 130℃, and the saturation of bound water was measured (32~34%). The crude oil was then saturated to the state of water-driven bound water. ③ Water drive basic recovery rate: Inject simulated formation water drive to the outlet end with a water cut of 98wt%, and record the water drive basic recovery rate; ④ Inject 0.3 PV (0.3 times the pore volume of the core) of the compound composition solution slug from Examples 11-13 and Example 1 (octadecylarylamide betaine: C8PO4). 10 (EO5C=7:3), followed by simulated formation water drive to the outlet end with a water cut of 98wt%; ⑤ Calculate Enhanced Oil Recovery: Total Oil Recovery minus Water Drive Base Oil Recovery equals the Enhanced Oil Recovery value of the compound composition system.

[0108] Experimental Results and Analysis The core flooding test results of different concentrations of the compound compositions in Examples 11-13 and Example 1 are shown in Table 8: Table 8

[0109] Results Analysis 1. The compound composition of the present invention can effectively improve the oil recovery rate of high-temperature and high-salinity oil reservoirs in the concentration range of 0.05~0.30wt%, with an improvement of 7.3~14.2 percentage points. Among them, when the concentration is ≥0.10wt%, the improvement in recovery rate is ≥10 percentage points. 2. As the concentration of the compound composition increases, the enhanced oil recovery value shows an upward trend. The difference in enhanced oil recovery between 0.20wt% and 0.30wt% concentrations is only 0.1 percentage points, indicating that 0.20wt% is the economically optimal concentration (balancing oil displacement effect and reagent cost), providing a concentration reference for field application. 3. No scaling or pore blockage was observed in the core after displacement, verifying the advantages of the alkali-free compound system of this invention. It avoids the problem of scale formation caused by the reaction of alkali flooding with calcium and magnesium ions in the formation. At the same time, it proves that the compound system has excellent compatibility with rocks and no risk of adsorption blockage or formation damage.

Claims

1. The application of a compound composition in the recovery of crude oil from high-temperature, high-salinity oil reservoirs, wherein the compound composition comprises arylalkylamide betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylate, wherein, The mass ratio of arylalkylamide betaine to alkyl polyoxypropylene polyoxyethylene ether carboxylate is (1.5~2.5):1; Among them, the properties of high-temperature and high-salinity oil reservoirs are as follows: the total salinity of formation water is (9~27)×10 4 mg / L, calcium and magnesium ion concentration is (0.3~1.5)×10 4 mg / L; temperature 130℃; The structural formula of arylalkylamide betaine is as follows: Where Ar is phenyl, methylphenyl, ethylphenyl, or dimethylphenyl, a and b are positive integers from 2 to 10, a+b=15, o=1~10, R1 and R2 are H or C1~C4 alkyl groups, and X - -CH(OH)CH2SO3 - or -COO - ; The structural formula of alkyl polyoxypropylene polyoxyethylene ether carboxylate is as follows: R-O-(CH2CH (CH3) O) m -(CH2CH2O) n -CH2COOM R is a C8 straight-chain alkyl group, M is an alkali metal cation, m is 10, and n is 5.

2. The application according to claim 1, characterized in that, The mass ratio of arylalkylamide betaine to alkyl polyoxypropylene polyoxyethylene ether carboxylate is 7:3 or 6:

4.

3. The application according to claim 1, characterized in that, When used, the compound composition is mixed with water, wherein the total mass percentage of arylalkylamide betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylate is 0.01~0.3wt%.

4. The application according to claim 1, characterized in that, When used, the compound composition is mixed with water, wherein the total mass percentage of arylalkylamide betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylate is 0.1~0.3wt%.

5. The application according to any one of claims 1-4, characterized in that, In arylalkylamide betaine, a = 7 and b = 8 or a = 8 and b = 7.

6. The application according to any one of claims 1-4, characterized in that, Ar is 3,5-dimethylphenyl.

7. The application according to any one of claims 1-4, characterized in that, R1 and R2 are methyl groups.

8. The application according to any one of claims 1-4, characterized in that, M represents sodium ions.

9. The application according to any one of claims 1-4, characterized in that, The properties of high-temperature and high-salinity oil reservoirs are: total salinity of (15~20)×10 4 mg / L, calcium and magnesium ion concentration (0.5~1.0)×10 4 mg / L.

10. The application according to claim 1, characterized in that, When used, the compound composition is mixed with water, wherein the total mass percentage of arylalkylamide betaine and alkyl polyoxypropylene polyoxyethylene ether carboxylate is 0.05~0.3wt%.

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