A functionalized ionic liquid clay stabilizer and a method of making the same

Abstract

The application discloses a kind of functionalized ionic liquid clay stabilizer and preparation method thereof, belong to oilfield chemical technical field.The functionalized ionic liquid clay stabilizer is prepared by the double quaternary ammonium salt of formula 1 and hydrogen bond donor, the structural formula of the double quaternary ammonium salt of formula 1 is: Wherein, R is selected from one or two of C1~C 16 Alkyl, hydroxyethyl, hydroxypropyl or aromatic group;X1 and X2 are selected from one or two of chlorine, bromine, fluorine or iodine;N is integer ≥2.The charge density of the functionalized ionic liquid clay stabilizer of the application is high, the anti-swelling effect is remarkable, the washing resistance is strong, the long-acting property is good, the temperature resistance is strong, can be used in high-temperature super-high-temperature reservoir, low-permeability super-low-permeability reservoir.Meanwhile, the functionalized ionic liquid clay stabilizer of the application has little influence on fracturing fluid performance, does not affect fracturing fluid sand-carrying performance, can be used in hydraulic fracturing.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oil field chemistry, and particularly relates to a functionalized ionic liquid clay stabilizer and a preparation method thereof. BACKGROUND

[0002] In the process of water injection development and acidification and fracturing reconstruction of oil fields, the clay minerals (kaolinite, montmorillonite, illite and chlorite, etc.) of the formation will swell, disperse and migrate when encountering external water or water-based substances, and even block the pore throat, resulting in a decrease in formation permeability and serious damage to low-permeability reservoirs. Therefore, a clay stabilizer is usually added to the well fluid to prevent the hydration swelling, dispersion and migration of clay, thereby protecting the reservoir. Generally, the surface of clay particles is negatively charged, and the cations in the clay stabilizer are positively charged, so that the two produce strong adsorption through electrostatic attraction, delay the penetration of water molecules, and prevent the hydration swelling of clay minerals, thereby playing an inhibitory role.

[0003] In the early stage, inorganic salts such as KCl and NH4Cl were used as clay stabilizers, which had the disadvantages of large dosage and certain influence on the performance of the well fluid. In the 1960s and 1970s, aluminum hydroxide or zirconium hydroxide was used as a clay stabilizer, which had the problems of poor temperature resistance and acid resistance. In recent years, the commonly used clay stabilizers mainly include quaternary ammonium salt surfactants, polyamines and polyquaternary ammonium salts. The above clay stabilizers all have good anti-swelling effect, but also have certain problems: the production process of polyamine clay stabilizer is relatively complex, the water washing resistance is poor, and the effective period is short; the polyquaternary ammonium salt clay stabilizer has large molecular weight, is not suitable for low-permeability reservoirs, and will increase the damage to the permeability of low-permeability reservoirs; the quaternary ammonium salt surfactant will make the reservoir become oil-wet, thereby reducing the oil phase permeability and being not conducive to oil recovery; in addition, the above types of clay stabilizers have poor compatibility with fracturing fluid, which will greatly reduce the sand carrying performance of the fracturing fluid and increase the difficulty of sand adding in fracturing construction; in some high-temperature and ultra-high-temperature reservoir environments, the conventional clay stabilizer will lose stability due to too high temperature, cannot effectively inhibit the hydration swelling of clay, and limits its application in high-temperature and ultra-high-temperature reservoirs.

[0004] Therefore, it has significant practical significance to develop clay stabilizers with excellent performance to reduce formation damage, prolong the service life of oil and gas wells, and realize the sustainable development of oil and gas resources. SUMMARY

[0005] In view of the problems in the background art, the main purpose of the present application is to provide a functionalized ionic liquid clay stabilizer and a preparation method thereof. The clay stabilizer of the present application is an ionic liquid constructed by small molecule compounds, has small molecular weight, high charge density, strong temperature resistance and water washing resistance, remarkable anti-swelling effect, and good compatibility with fracturing fluid, and has less influence on the performance of the fracturing fluid.

[0006] To achieve the above objectives, the present invention provides a functionalized ionic liquid clay stabilizer, prepared by a bis-quaternary ammonium salt of Formula 1 and hydrogen bond donors, wherein the structural formula of the bis-quaternary ammonium salt is:

[0007] Formula 1;

[0008] Wherein, R is selected from C1~C 16 One or two of alkyl, hydroxyethyl, hydroxypropyl or aryl groups; X1 and X2 are selected from one or two of chlorine, bromine, fluorine or iodine; n is an integer ≥2.

[0009] Furthermore, the hydrogen bond donor is selected from one or more of urea, thiourea, ethylene glycol, or glycerol.

[0010] Furthermore, n is an integer from 2 to 6.

[0011] In another aspect, the present invention provides a method for preparing a functionalized ionic liquid clay stabilizer, comprising the following steps:

[0012] A tertiary amine compound, α,ω-dihaloalkane, and hydrogen bond donor are mixed and reacted, wherein the tertiary amine compound and the α,ω-dihaloalkane react to generate a bisquaternary ammonium salt of Formula 1, and the bisquaternary ammonium salt reacts with the hydrogen bond donor to obtain the functionalized ionic liquid clay stabilizer.

[0013] The structural formula of the bisquaternary ammonium salt is as follows:

[0014] Formula 1.

[0015] Furthermore, the temperature of the mixing reaction is 50~100℃, and the time is 6~24h.

[0016] Furthermore, the mixed reaction is carried out in two stages of heating. The temperature of the first stage reaction is 50~70℃ and the time is 2~6h. The temperature of the second stage reaction is 70~100℃ and the time is 4~18h.

[0017] Furthermore, the hydrogen bond donor is selected from one or more of urea, thiourea, ethylene glycol, or glycerol.

[0018] Furthermore, the tertiary amine compound has the following structural formula:

[0019] ;

[0020] Wherein, R is selected from C1~C 16 It is one or two of the alkyl, hydroxyethyl, hydroxypropyl or aromatic groups.

[0021] Furthermore, the α,ω-dihaloalkane has the following structural formula:

[0022] ;

[0023] Where X1 and X2 are one or two of chlorine, bromine, fluorine or iodine, and n is an integer ≥2.

[0024] Furthermore, the molar ratio of hydrogen bond donor, tertiary amine compound and α,ω-dihaloalkane is 1~4:2~2.5:1.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The functionalized ionic liquid clay stabilizer of the present invention is composed of a low molecular weight bisquaternary ammonium salt and a hydrogen bond donor, which will not cause secondary damage to the reservoir and can be used in low-permeability and ultra-low-permeability reservoirs. In addition, the functionalized ionic liquid clay stabilizer of the present invention has high charge density, significant anti-swelling effect, strong water washing resistance, good long-term effect, and strong temperature resistance, and can be used in high-temperature and ultra-high-temperature reservoirs. At the same time, the functionalized ionic liquid clay stabilizer of the present invention has little impact on the performance of fracturing fluid and will not affect the proppant carrying capacity of fracturing fluid, and can be used in hydraulic fracturing.

[0027] (2) The preparation method of the functionalized ionic liquid clay stabilizer of the present invention involves reacting a tertiary amine compound with an α,ω-dihaloalkane to generate a bis-quaternary ammonium salt. The bis-quaternary ammonium salt then forms an ionic liquid with a hydrogen bond donor. This ionic liquid can serve as a solvent for the bis-quaternary ammonium salt formation reaction, promoting the quaternization reaction and increasing the yield of the ionic liquid. The preparation method of the present invention is simple, the reaction process is safe and controllable, and it is suitable for large-scale production. Attached Figure Description

[0028] Figure 1 The chemical reaction formula for preparing a functionalized ionic liquid clay stabilizer is shown in one embodiment of the present invention. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range. The invention will now be described in detail with reference to embodiments.

[0030] To achieve the above objectives, embodiments of the present invention provide a functionalized ionic liquid clay stabilizer, prepared by a bis-quaternary ammonium salt of Formula 1 and hydrogen bond donors, wherein the structural formula of the bis-quaternary ammonium salt is:

[0031] Formula 1;

[0032] Wherein, R is selected from C1~C 16 The alkyl, hydroxyethyl, hydroxypropyl, or aromatic group is selected from one or two of the following: alkyl, hydroxyethyl, hydroxypropyl, or aromatic group; further, the aromatic group is preferably phenyl, benzyl, or phenethyl; X1 and X2 are selected from one or two of the following: chlorine, bromine, fluorine, or iodine; n is an integer ≥2. Further, n is preferably an integer from 2 to 6.

[0033] In order to further improve the anti-swelling effect of functionalized ionic liquid clay stabilizers and reduce raw material costs, in some preferred embodiments of the present invention, the hydrogen bond donor is selected from one or more of urea, thiourea, ethylene glycol or glycerol.

[0034] In another aspect, the present invention provides a method for preparing the aforementioned functionalized ionic liquid clay stabilizer, comprising the following steps: mixing and reacting a tertiary amine compound, an α,ω-dihaloalkane, and a hydrogen bond donor, wherein the tertiary amine compound and the α,ω-dihaloalkane react to generate a bisquaternary ammonium salt of Formula 1, and the bisquaternary ammonium salt reacts with the hydrogen bond donor to obtain the functionalized ionic liquid clay stabilizer;

[0035] The structural formula of the bisquaternary ammonium salt is as follows:

[0036] Formula 1.

[0037] In a preferred embodiment of the present invention, the tertiary amine compound has the following structural formula:

[0038] Where R is selected from C1 to C2. 16 It contains one or two of alkyl, hydroxyethyl, hydroxypropyl, or aromatic groups; further, the aromatic group is preferably phenyl, benzyl, or phenethyl.

[0039] In a preferred embodiment of the present invention, the α,ω-dihaloalkane has the following structural formula:

[0040] Wherein, X1 and X2 are selected from one or two of chlorine, bromine, fluorine or iodine, preferably chlorine or bromine, and n is an integer ≥2, preferably a positive integer from 2 to 6, and more preferably 3 or 4.

[0041] In a preferred embodiment of the present invention, the molar ratio of the hydrogen bond donor, the tertiary amine compound, and the α,ω-dihaloalkane is 1~4:2~2.5:1. The present invention, by synergistically controlling the proportions of the above three components, enables the functionalized ionic liquid clay stabilizer generated by the reaction to possess suitable ionic liquid viscosity and charge density, significantly improving its anti-swelling effect, water washability, and temperature resistance. If the proportion of the hydrogen bond donor in the present invention is too high, the cation concentration of the synthesized ionic liquid is too low, resulting in a decrease in the performance of the clay stabilizer. If the proportion of the hydrogen bond donor is too low, the performance of the clay stabilizer is also reduced. This is because a low proportion of the hydrogen bond donor leads to incomplete reaction; the hydrogen bond donor does not react completely with the bisquaternary ammonium salt of Formula 1, making it difficult to form a uniform ionic liquid form of the clay stabilizer. Most of the stabilizer remains as a bisquaternary ammonium salt solid, and the resulting solid-liquid mixture is difficult to apply effectively in the field.

[0042] In a preferred embodiment of the present invention, the temperature of the mixing reaction is 50-100°C, and the time is 6-24 hours. More preferably, the mixing reaction is carried out in two stages with increasing temperature: the first stage reaction is carried out at 50-70°C for 2-6 hours, and the second stage reaction is carried out at 70-100°C for 4-18 hours. The present invention employs a two-stage reaction. The initial lower temperature prevents the hydrogen bond donor from volatilizing. After the reaction has proceeded for a period of time, the resulting quaternary ammonium salt combines with the hydrogen bond donor to form a functionalized ionic liquid clay stabilizer. This enhances the temperature resistance of the reaction system, thereby allowing for an increase in the temperature of the second stage reaction and a higher reaction rate.

[0043] In one exemplary embodiment of the present invention, urea is used as an example of a hydrogen bond donor. Figure 1 The chemical reaction process for preparing functionalized ionic liquid clay stabilizers is as follows:

[0044] .

[0045] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0046] Example 1

[0047] The preparation method of the functionalized ionic liquid clay stabilizer in this embodiment includes the following steps:

[0048] 0.2 mol of urea, 0.1 mol of dimethylethanolamine and 0.05 mol of 1,4-dichlorobutane were mixed and stirred until the urea was evenly dispersed. The mixture was heated to 50 °C and reacted for 6 h. Then the temperature was increased to 90 °C and reacted for 12 h to obtain a functionalized ionic liquid clay stabilizer.

[0049] Example 2

[0050] The preparation method of the functionalized ionic liquid clay stabilizer in this embodiment includes the following steps:

[0051] 0.1 mol of thiourea, 0.1 mol of ethylene glycol, 0.1 mol of dimethylethanolamine and 0.05 mol of 1,4-dichlorobutane were mixed and stirred until the thiourea was evenly dispersed. The mixture was heated to 50°C and reacted for 6 h, then at 90°C for 12 h to obtain a functionalized ionic liquid clay stabilizer.

[0052] Example 3

[0053] The preparation method of the functionalized ionic liquid clay stabilizer in this embodiment includes the following steps:

[0054] 0.1 mol of ethylene glycol, 0.1 mol of dimethylethanolamine and 0.05 mol of 1,3-dichloropropane were mixed evenly, and the mixture was heated to 50 °C for 4 h and then to 90 °C for 8 h to obtain a functionalized ionic liquid clay stabilizer.

[0055] Example 4

[0056] The preparation method of the functionalized ionic liquid clay stabilizer in this embodiment includes the following steps:

[0057] 0.1 mol of ethylene glycol, 0.1 mol of dimethyl benzylamine and 0.05 mol of 1,3-dichloropropane were mixed evenly, and the mixture was heated to 50 °C for 4 h and then to 90 °C for 8 h to obtain a functionalized ionic liquid clay stabilizer.

[0058] Example 5

[0059] The preparation method of the functionalized ionic liquid clay stabilizer in this embodiment includes the following steps:

[0060] 0.1 mol of ethylene glycol, 0.05 mol of glycerol, 0.09 mol of dimethylethanolamine, 0.01 mol of dodecylamine and 0.05 mol of 1,3-dichloropropane were mixed evenly, heated to 50 °C for 4 h, and then reacted at 90 °C for 8 h to obtain a functionalized ionic liquid clay stabilizer.

[0061] Comparative Example 1

[0062] 0.25 mol of urea, 0.1 mol of dimethylethanolamine and 0.05 mol of 1,4-dichlorobutane were mixed and stirred until the urea was evenly dispersed. The mixture was heated to 50 °C and reacted for 6 h. Then the temperature was increased to 90 °C and reacted for 12 h to obtain a functionalized ionic liquid clay stabilizer.

[0063] Comparative Example 2

[0064] 0.25 mol of ethylene glycol, 0.1 mol of dimethylethanolamine and 0.05 mol of 1,3-dichloropropane were mixed evenly, and the mixture was heated to 50 °C for 4 h and then to 90 °C for 8 h to obtain a functionalized ionic liquid clay stabilizer.

[0065] Performance testing

[0066] Test Example 1: Evaluation of the anti-swelling rate of clay stabilizers:

[0067] Take 0.7g of clay stabilizer, add 100g of distilled water and shake well to obtain a clay stabilizer solution. Weigh 0.50g of sodium bentonite, put it into a 10mL centrifuge tube, add 10mL of clay stabilizer solution, shake well, let stand at room temperature for 2 hours, put it into a centrifuge, centrifuge at 1500r / min for 15 minutes, and read the volume V1 of the expanded sodium bentonite.

[0068] The volume V2 of sodium bentonite after expansion is calculated by replacing the clay stabilizer solution with distilled water.

[0069] When kerosene is used instead of clay stabilizer solution, the volume V0 of sodium bentonite after expansion is calculated.

[0070] Method for calculating anti-swelling rate:

[0071]

[0072] The anti-swelling rate test results of the clay stabilizer of this invention are shown in Table 1.

[0073] Test Example 2: Evaluation of the water wash resistance of clay stabilizers:

[0074] Discard the supernatant in the centrifuge tube after centrifugation in Test Example 1, add 10 mL of distilled water, shake well, let stand for 2 hours, put it into a centrifuge, centrifuge at 1500 r / min for 15 min, repeat the above operation twice, read the volume of sodium bentonite after expansion, and calculate the anti-swelling rate in the same way as in Test Example 1.

[0075] The test results of the water wash resistance of the clay stabilizer of the present invention are shown in Table 1.

[0076] Test Example 3: Evaluation of the gel viscosity retention rate of clay stabilizers:

[0077] Prepare 1000 mL of 0.4% hydroxypropyl guar gum fracturing fluid base, divide it into two equal parts, one part is a blank sample, and the other part contains 0.7% clay stabilizer by mass.

[0078] The fracturing fluid crosslinking fluid formula is prepared by using sodium tetraborate with a mass fraction of 3.0% and sodium hydroxide with a mass fraction of 10.0%.

[0079] Two portions of fracturing fluid base fluid were prepared into fracturing fluid gel according to the crosslinking ratio required by the test or a crosslinking ratio of 100:1. Then, the apparent viscosity of the two gel samples at 90℃ was measured.

[0080] Method for calculating the viscosity retention rate of gel:

[0081]

[0082] y1 — Viscosity retention rate, expressed as a percentage;

[0083] η2 — apparent viscosity with clay stabilizer added, mPa·s;

[0084] η1 — apparent viscosity of blank sample, mPa·s.

[0085] The test results of the gel viscosity retention rate of the clay stabilizer of the present invention are shown in Table 1.

[0086] The clay stabilizer solution was placed in a high-temperature and high-pressure heat treatment sealed container and heat-treated at 300°C for 2 hours. The above operation was repeated to test the temperature resistance of the clay stabilizer. The test results are shown in Table 1.

[0087] Table 1

[0088]

[0089] The test results show that the clay stabilizer prepared in the embodiments of this invention has an anti-swelling rate of ≥85%, a water-washed anti-swelling rate of ≥80%, a gel viscosity retention rate of ≥90%, and a temperature resistance of up to 300℃, demonstrating excellent performance and suitability for fracturing and stimulation of high-temperature, ultra-high-temperature, and ultra-low-permeability reservoirs. In contrast, the anti-swelling rate and water-washed anti-swelling rate of the clay stabilizer prepared in the comparative example show a significant decrease. This is because the comparative clay stabilizer preparation process used an excessively high amount of hydrogen bond donors, reducing the effective cation concentration and consequently resulting in a poorer anti-swelling effect.

[0090] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. The present invention can also be implemented in other specific ways or forms without departing from its spirit or essential characteristics. Therefore, the described embodiments should be considered illustrative rather than limiting in any respect. The scope of the present invention should be defined by the appended claims, and any variations equivalent to the intent and scope of the claims should also be included within the scope of the present invention.

Claims

1. A functionalized ionic liquid clay stabilizer, characterized in that, The bisquaternary ammonium salt of formula 1, prepared by reacting a tertiary amine compound with an α,ω-dihaloalkane, and a hydrogen bond donor are used to obtain the bisquaternary ammonium salt, the structural formula of which is: Formula 1; Wherein, R is selected from C1~C 16 The alkyl, hydroxyethyl, hydroxypropyl, or aromatic group is selected from phenyl, benzyl, or phenethyl; X1 and X2 are selected from chlorine, bromine, fluorine, or iodine; n is an integer from 2 to 6; the hydrogen bond donor is selected from one or more of urea, thiourea, ethylene glycol, or glycerol; the molar ratio of the hydrogen bond donor, tertiary amine compound, and α,ω-dihaloalkane is 1 to 4: 2 to 2.5:

1.

2. A method for preparing the functionalized ionic liquid clay stabilizer as described in claim 1, characterized in that, Includes the following steps: A tertiary amine compound, α,ω-dihaloalkane, and hydrogen bond donor are mixed and reacted, wherein the tertiary amine compound and the α,ω-dihaloalkane react to generate a bisquaternary ammonium salt of Formula 1, and the bisquaternary ammonium salt reacts with the hydrogen bond donor to obtain the functionalized ionic liquid clay stabilizer. The structural formula of the bisquaternary ammonium salt is as follows: Formula 1.

3. The preparation method of the functionalized ionic liquid clay stabilizer according to claim 2, characterized in that, The mixing reaction is carried out at a temperature of 50~100℃ for 6~24h.

4. The preparation method of the functionalized ionic liquid clay stabilizer according to claim 2, characterized in that, The mixed reaction is carried out in two stages of heating. The temperature of the first stage reaction is 50~70℃ and the time is 2~6h. The temperature of the second stage reaction is 70~100℃ and the time is 4~18h.

5. The preparation method of the functionalized ionic liquid clay stabilizer according to claim 2, characterized in that, The tertiary amine compound has the following structural formula: ； Wherein, R is selected from C1~C 16 It is selected from one or two of alkyl, hydroxyethyl, hydroxypropyl or aromatic groups, wherein the aromatic group is selected from phenyl, benzyl or phenylethyl.

6. The method for preparing the functionalized ionic liquid clay stabilizer according to claim 2, characterized in that, The α,ω-dihaloalkane has the following structural formula: ； Where X1 and X2 are selected from one or two of chlorine, bromine, fluorine or iodine, and n is an integer from 2 to 6.

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