CN104830301A - Vesicle oil displacement agent formed from gemini surfactant, and applications of vesicle oil displacement agent in crude oil recovery rate increase - Google Patents

Abstract

The invention relates to a vesicle oil displacement agent formed by gemini surfactants, which is prepared by mixing gemini surfactants and mineralized water, wherein the mass concentration of gemini surfactants is 0.02% to 0.2wt%, and the gemini surfactants The molecule contains at least two negatively charged polar hydrophilic groups and one or two hydrophobic groups; a single hydrophobic group has a carbon chain length of 8-24 and contains a benzene ring or a cycloalkyl group. The vesicle oil displacement agent formed by the gemini surfactant of the present invention has a strong interfacial adsorption tendency, and can form an ultra-low interfacial tension of 10 ^-3 mN·m ^-1 with crude oil without adding any alkali, and has a short onset time, and can be used in It can reduce the interfacial tension to 10 ^-3 mN·m ^-1 within 10-15 minutes, and can be used alone or combined with polymers to form a binary flooding system, which can be used in tertiary oil recovery to enhance oil recovery.

Description

A vesicle oil displacement agent formed by gemini surfactant and its application in enhanced oil recovery

technical field

The invention relates to a vesicle oil displacement agent formed by gemini surfactants, which can quickly reduce the interfacial tension of oil and water to an ultra-low (10 ^-3 mN·m ^-1 ), and is applied in tertiary oil recovery to improve crude oil recovery, belonging to Field of oilfield chemical technology.

Background technique

Petroleum is a very important non-renewable resource. With the rapid economic growth, the society's demand for oil has risen sharply, and the possibility of rediscovering large reserves of oil reservoirs has decreased, making the improvement of the recovery rate of developed oil fields attract much attention. It is imminent to adopt technical means to enhance the recovery factor of developed oilfields.

During oil production, the fluid flow in the reservoir is affected by geological factors such as reservoir sandstone pore structure and system wettability, as well as factors such as crude oil/water interfacial tension. Because the surfactant has interfacial activity, it can significantly reduce the oil/water interfacial tension, increase the capillary number, and promote the desorption and effective dispersion of crude oil from the rock, so as to effectively drive the residual oil and improve the recovery factor. The most commonly used oil repellant. To reduce the oil-water interfacial tension to an ultra-low 10 ^-3 mN·m ^-1 is an important index for screening surfactants as chemical oil displacement agents.

At present, the development potential of high-salt reservoirs is great, but due to the challenge brought by high salinity to the salt resistance of surfactants, most surfactant systems lose their interfacial activity due to precipitation under high-salt conditions, and can be applied to high-salt reservoirs. Oil displacement agents and related technologies for enhanced oil recovery in salt reservoirs are seriously lacking.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a vesicle oil-displacing agent formed of gemini surfactants, which can reduce the oil-water interfacial tension to an ultra-low level and is suitable for tertiary oil recovery Enhanced oil recovery. The vesicle oil displacement agent formed by the gemini surfactant of the present invention has good adaptability to mineralized water, and can also form vesicles under high-salt conditions, which can further reduce interfacial tension, and is especially suitable for high-salt oil Reservoir enhanced oil recovery.

Technical scheme of the present invention is as follows:

A vesicle oil-displacing agent formed by a gemini surfactant, characterized in that, the vesicle oil-displacing agent is obtained by adding the gemini surfactant into mineralized water at 20-30°C and stirring for 0.2-0.5h to obtain ;

In the vesicle oil displacement agent, the mass concentration of the gemini surfactant is 0.02%-0.2wt%, and the total salinity of the mineralized water is 20000-24000ppm;

The gemini surfactant molecule contains at least two negatively charged polar hydrophilic groups and one or two hydrophobic groups; the carbon chain length of a single hydrophobic group is C8-C24 and contains a benzene ring or a cycloalkyl group.

Preferably in the present invention, the mass concentration of the gemini surfactant is 0.08%-0.18wt%, and the total salinity of the mineralized water is 22000-23000ppm.

Preferably in the present invention, the mass concentration of the gemini surfactant is 0.10%-0.15wt%.

Preferably in the present invention, the mass concentration of the gemini surfactant is 0.16%-0.18wt%.

Preferably in the present invention, the gemini surfactant is dialkyl diphenyl ether disulfonate, dialkyl diphenyl ether dicarboxylate or dimer carboxylate anionic gemini surfactant.

Above-mentioned dialkyl diphenyl ether bissulfonate can be prior art, and the present invention is preferred, and makes as follows:

(1) Primary alcohol and thionyl chloride are mixed in a molar ratio of 1:2, and dimethylformamide (DMF) catalyst is added and heated to 60-80°C, reacted for 7-9 hours, and the catalyst is added to obtain chloroalkane;

(2) Mix chloroalkane with diphenyl ether, the mass ratio of chloroalkane to diphenyl ether is 1:2, add anhydrous aluminum trichloride as catalyst, the molar ratio of catalyst to diphenyl ether is (2～3 ): (6~10), heated to 60~80°C, reacted for 3~5h, after suction filtration and vacuum distillation, dialkyl diphenyl ether was obtained;

(3) Add oleum with a mass concentration of 30-40% to the dialkyl diphenyl ether, the molar ratio of diphenyl ether to oleum in the dialkyl diphenyl ether is 1: (2 to 3), and the bis The molar ratio of alkyl and fuming sulfuric acid in alkyl diphenyl ether = 1: (2 ~ 4), reaction temperature = 50 ~ 60 ° C, reaction time = 0.5 ~ 1 h, after filtration and purification, dialkyl diphenyl ether is obtained Phenyl ether sulfonate.

The structural formula of double alkyl diphenyl ether sulfonate is as follows:

Wherein: R ₁ ＝C _n H _2n+1 ; R ₂ ＝H or C _n H _2n+1 ;

The application of the vesicular oil displacement agent formed by the above-mentioned gemini surfactants is applied to ordinary low-permeability reservoirs, carbonate reservoirs, and conventional sandstone reservoirs in the late stage of high water cut or to enhance oil recovery after polymer injection. Gemini surfactants The salinity range that the vesicle flooding agent can tolerate is: the total salinity is 0-30,000ppm, and the total concentration of calcium and magnesium ions is 0-1,000ppm.

The technical characteristics and beneficial effects of the vesicle oil displacement agent formed by the gemini surfactant of the present invention:

The gemini surfactant of the present invention can not only form a vesicle oil displacement agent by itself under the induction of calcium and magnesium ions, but also can keep the vesicle association structure from being damaged when used in combination with other surfactants or polymers. The vesicle has a strong tendency to adsorb at the oil-water interface, and the in-situ assembly forms a predetermined interface layer, which makes the oil-water interfacial tension drop to an ultra-low, lower than 10- ³ mN m- ¹ . The interface layer is less affected by the composition of crude oil and has good reservoir adaptability. This vesicular oil displacing agent also has the following excellent properties:

(1) The vesicle oil displacement agent formed by the gemini surfactant of the present invention has a strong interfacial adsorption tendency, and can form an ultra-low interfacial tension of 10 ^-3 mN·m ^-1 with crude oil without adding any alkali, and the onset time is short , the interfacial tension can be reduced to 10 ^-3 mN·m ^-1 within 10-15 minutes.

(2) The use concentration is low, and it has strong adaptability to oil phases of different compositions. The amount used is far less than the amount of current field oil displacement agent, and the interfacial tension can reach the order of 10 ^-3 mN·m ^-1 , which is beneficial to reduce the cost of tertiary recovery Cost of production.

(3) The vesicle oil displacement agent formed by the gemini surfactant of the present invention can still reduce interfacial tension preferably at a higher salinity, has good salt resistance and good thermal stability, and is effective in improving high-salt oil reservoirs. It has a great application prospect in terms of oil recovery.

(4) The present invention has a single composition, avoids the disappearance of ultra-low surface tension caused by the difference in properties of the components to a certain extent, has simple process, easy control of reaction, and wide application range.

Description of drawings

Fig. 1 is the transmission electron micrograph of the vesicle oil displacement agent that embodiment 1 makes;

Figure 2 is a transmission electron micrograph of the vesicle oil displacement agent prepared in Example 2.

detailed description

The present invention will be further described below in conjunction with the embodiments and accompanying drawings, but not limited thereto.

Example 1:

A vesicle oil-displacing agent formed by gemini surfactants is prepared by adding gemini surfactants into mineralized water with a total salinity of 20,000 ppm and stirring for 0.5 hours at 25°C to obtain a vesicle-forming oil-displacing agent; mineralized Water ions are composed of sodium ions, calcium ions, magnesium ions and chloride ions.

In the vesicle oil displacement agent, the mass concentration of gemini surfactant is 0.18wt%, and its scanning electron micrograph is shown in Fig. 1 . The gemini surfactant is sodium didodecyl diphenyl ether disulfonate.

The product is tested for interfacial tension:

1. Test instrument: TEXAS-500 spinning drop interfacial tensiometer

2. Temperature: 50°C,

3. Crude oil: experimental standard crude oil (provided by Shengli Oilfield)

4. Water: distilled water

5. Vesicle oil displacing agent: Example 1, main component (w%)

Put the sample tube filled with the above-mentioned solution into it, and after it stabilizes for half an hour, add about 1 microliter of Shengli crude oil with a micro syringe, and read the interfacial tension at regular intervals according to the national standard SY/T5370-1999 method. The tension reaches 0.00381mN/m.

The effects of different concentrations of vesicle oil displacement agents on interfacial tension are shown in Table 1:

Table 1

Vesicle displacement agent concentration (wt%) Interfacial tension (mN·m ^-1 ) 0.1 0.015 0.15 0.0102 0.18 0.00381 0.25 0.00378 0.30 0.00359 0.35 0.00362 0.4 0.00338

Example 2:

A vesicle oil-displacing agent formed by gemini surfactants is obtained by adding gemini surfactants into mineralized water with a total salinity of 23,000 ppm and stirring for 0.5 hours at 30°C to obtain a vesicle-forming oil-displacing agent; mineralization Water ions are composed of calcium ions, magnesium ions and chloride ions.

In the vesicle oil displacement agent, the mass concentration of the gemini surfactant is 0.1wt%, and its scanning electron micrograph is shown in Fig. 2 . The gemini surfactant is sodium didodecyl diphenyl ether dicarboxylate.

The product is carried out interfacial tension test, and the test instrument, crude oil, water, temperature used are the same as embodiment 1;

Vesicle oil displacing agent: embodiment 2, main component (w%)

Put the sample tube filled with the above-mentioned solution into it, and after it is stable for half an hour, add about 1 microliter of Xinjiang Karamay crude oil with a micro-syringe, and read the interfacial tension at regular intervals according to the national standard SY/T5370-1999 method, within 15 minutes The interfacial tension reaches 0.00831mN/m.

The results of the effects of different concentrations of vesicle oil displacement agents on interfacial tension are shown in Table 2:

Table 2

Vesicle displacement agent concentration (w%) Interfacial tension (mN·m ^-1 ) 0.05 0.0156 0.1 0.00831 0.15 0.00820 0.2 0.00819 0.25 0.00752 0.3 0.00748 0.35 0.00736

Example 3:

A vesicle oil-displacing agent formed by gemini surfactants is obtained by adding gemini surfactants into mineralized water with a total salinity of 21,000 ppm and stirring for 0.5 hours at 30°C to obtain a vesicle-forming oil-displacing agent; mineralization Water ions are composed of calcium ions, magnesium ions and chloride ions.

In the vesicle oil displacement agent, the mass concentration of the gemini surfactant is 0.08wt%, and the gemini surfactant is dimer sodium carboxylate.

The product is carried out interfacial tension test, and the test instrument, crude oil, water, temperature used are the same as embodiment 1;

Vesicle oil displacing agent: embodiment 3, main component (w%)

The effects of different concentrations of vesicle oil displacement agents on interfacial tension are shown in Table 3:

table 3

Vesicle displacement agent concentration (w%) Interfacial tension (mN·m ^-1 ) 0.05 0.0125 0.08 0.00645 0.1 0.00638 0.15 0.00582 0.2 0.00579 0.25 0.00565 0.3 0.00570

Comparative example: Commercially available sodium didodecyl diphenyl ether disulfonate

Salt resistance test:

The vesicle oil displacement agent of Examples 1-3 and the commercially available product dialkyl diphenyl ether disulfonate were used to measure the surface tension with simulated formation water under the same conditions, and the test results are shown in Table 5:

Table 4 Composition of simulated formation water

Table 5 The interfacial tension of the vesicle flooding agent of Example 1-3 and the comparative example versus simulated formation water

product Interfacial tension (mN·m ^-1 ) Example 1 0.00381

Example 2 0.00831 Example 3 0.00645 comparative example 0.0128

Result: As can be seen from Table 5, under the condition that the salinity is greater than 30000mg/L, the vesicle oil displacement agents of Examples 1-3 of the present invention have ultra-low surface tension, while the comparative examples do not have Surface activity, the invention has better salt resistance and can meet the use requirements of high-salt oil reservoirs.

Claims (7)

1. Gemini surface active agent formed a vesica oil-displacing agent, it is characterized in that, described vesica oil-displacing agent be by Gemini surface active agent at 20-30 DEG C, add in mineralized water stir 0.2 ~ 0.5h, obtain;

In vesica oil-displacing agent, the mass concentration of described Gemini surface active agent is 0.02% ~ 0.2wt%, and the total mineralization of described mineralized water is 20000 ~ 24000ppm;

Described Gemini surface active agent molecule contains at least two electronegative polar hydrophilic groups and two hydrophobic groupings; Single hydrophobic group carbon chain lengths is C8-C24 and contains phenyl ring or cycloalkyl.

2. the vesica oil-displacing agent of Gemini surface active agent formation according to claim 1, it is characterized in that, the mass concentration of Gemini surface active agent is 0.08% ~ 0.18wt%, and the total mineralization of mineralized water is 22000 ~ 23000ppm.

3. the vesica oil-displacing agent of Gemini surface active agent formation according to claim 2, it is characterized in that, the mass concentration of Gemini surface active agent is 0.10% ~ 0.15wt%.

4. the vesica oil-displacing agent of Gemini surface active agent formation according to claim 2, it is characterized in that, the mass concentration of Gemini surface active agent is 0.16% ~ 0.18wt%.

5. the vesica oil-displacing agent of Gemini surface active agent formation according to claim 1, it is characterized in that, described Gemini surface active agent is two p alkylphenylaceticacid, dimeric carboxylate gemini surfactant or alkylamidoalkyl diphenyl oxide disulfonate.

6. the vesica oil-displacing agent of Gemini surface active agent formation according to claim 5, it is characterized in that, two p alkylphenylaceticacid obtains as follows:

(1) primary alconol and thionyl chloride mix with the ratio of mol ratio 1:2, add dimethyl formamide (DMF) catalyzer and are heated to 60 ~ 80 DEG C, and reaction 7 ~ 9h, adds catalyzer and obtain alkyl chloride;

(2) alkyl chloride is mixed with phenyl ether, the mass ratio 1:2 of alkyl chloride and phenyl ether, add aluminum trichloride (anhydrous) as catalyzer, the mol ratio of catalyzer and phenyl ether is (2 ~ 3): (6 ~ 10), be heated to 60 ~ 80 DEG C, reaction 3 ~ 5h, after suction filtration and underpressure distillation, obtains two alkyl diphenyl ether;

(3) in two alkyl diphenyl ether, add the oleum of mass concentration 30-40%, in two alkyl diphenyl ether, the mol ratio of phenyl ether and oleum is 1:(2 ~ 3), mol ratio=1:(2 ~ 4 of alkyl and oleum in two alkyl diphenyl ether), temperature of reaction=50 ~ 60 DEG C, reaction times=0.5 ~ 1h, obtained two alkyl diphenyl ether sulfonate after filtering, purifying.

7. the application of the vesica oil-displacing agent of Gemini surface active agent formation according to claim 1, can apply separately or with polymer formation binary displacement oil system, recovery ratio is improved after being applied to low-permeability oil deposit, carbonate oil reservoir, conventional sandstone oil reservoir late high water content period or polymer injection, the salinity range of Gemini surface active agent vesica oil-displacing agent tolerance is: total mineralization 0-30,000ppm, calcium ions and magnesium ions total concn 0-1,000ppm.