RU2200056C2 - Emulsifier for invert emulsions - Google Patents

Abstract

FIELD: oil and gas production. SUBSTANCE: invention is intended for preparing homogenous mixtures of two immiscible liquids such as oil and water used in oil and gas production operations. Emulsifier contains oil-soluble surfactant and hydrocarbon solvent. The former is represented by Emultal, i.e. tallow oil esters with triethanolamine, or emulsifier Neftenol NZ base, i.e. mixture of tallow oil esters with triethanolamine and tallow oil esters with oxyethylated alkylamine. First-type emulsifier includes following components, wt %: oil-soluble surfactant 20.0- 40.0, calcium chloride 1.0-3.4, water 2.0-6.8, organobentonite 3.6-10.8, and hydrocarbon solvent - the balance. Second- type emulsifier has, as solid phase, bentonite clay modified by quaternary ammonium salt and, in particular, contains, wt %: oil-soluble surfactant 20.0-40.0, calcium chloride 1.0-3.4, water 2.0-6.8, bentonite clay 2.4-7.2, quaternary ammonium salt 1.2-4.3, and hydrocarbon solvent - the balance. EFFECT: increased temperature resistance and aggregative stability of invert emulsions. 2 cl, 6 tbl, 36 ex

Description

 The invention relates to invert emulsifiers and can be used to obtain a homogeneous mixture of two immiscible liquids, such as oil and water, oil and water, etc., used in the oil and gas industry, including the oil industry to increase oil recovery formations by flooding during the primary and secondary impact on the oil reservoir.

 Known emulsifier emulsifier, which is a mixture of esters of oleic, linolenic, linoleic, as well as resin acids contained in tall oil distillate, and triethanolamine [1].

 The disadvantages of the emulsion include low emulsifying ability, especially with respect to hydrocarbon media with a low content of aromatic hydrocarbons, leading to an increase in the operating costs of the emulsifier, and a high pour point, which makes it difficult to use the emulsifier in the cold period in the eastern and northern regions.

Known emulsifier Neftenol NZT, which includes an oil-soluble surfactant - salts of alkyl polyamines and fatty acids of the general formula R- [NH ₂ ⁺ CH ₂ ) ₃ ] _n NH ₃ ⁺ [R ₁ COO] ^- _n , where R, R ₁ are hydrocarbon radicals of fatty acids from the series C ₈ -C ₂₄ , n = 2 .... 3, the polar solvent is fatty alcohols or waste products and a hydrocarbon solvent [2]. The disadvantages of the emulsifier are its low aggregative stability, unsatisfactory rheological properties of the emulsions obtained on its basis.

Closest to the proposed technical solution (RU 2062142 C1, 1996) is an invert emulsion emulsifier Neftenol NZ, which contains tall oil acid esters of triethanolamine, tall oil acid and ethoxylated alkylamine esters and a hydrocarbon solvent (aromatic hydrocarbon fraction) in the following the ratio of components, wt.%:
Oil Soluble Surfactant - 41.0-55.0
Hydrocarbon solvent - Up to 100.0
[3, prototype]
The disadvantages of the emulsifier of the prototype are not sufficiently high thermal stability and aggregative stability, as well as poor rheological properties due to a sharp decrease in viscosity with increasing temperature obtained on the basis of inverse emulsions, which reduces the effectiveness of its use.

The present invention solves the problem of increasing the thermal stability and aggregative stability of inverse emulsions obtained on the basis of the proposed emulsifier, as well as improving their rheological parameters with increasing temperature, which is achieved by additional introduction of water, calcium chloride and solid phase in the form of organobentonite into the emulsifier in the following the ratio of components, wt.%:
Oil-soluble surfactant (emulsifier or base emulsifier Neftenol NZ) - 20,0-40, O
Calcium Chloride - 1.0-3.4
Water - 2.0-6.8
Organobentonite - 3.6-10.8
Hydrocarbon solvent - Up to 100.0
Preferably, the emulsifier additionally contains water, calcium chloride and a solid phase in the form of bentonite clay, modified Quaternary ammonium salt (HOUR), in the following ratio, wt.%:
Oil-soluble surfactant (emulsifier or base emulsifier Neftenol NZ) - 20.0-40.0
Calcium Chloride - 1.0-3.4
Water - 2.0-6.8
Bentonite clay - 2.4-7.2
Quaternary ammonium salt (HOUR) - 1.2-4.3
Hydrocarbon solvent - Up to 100.0
The features of the invention "Emulsifier of invert emulsions" is the composition of the emulsifier:
1. As an oil-soluble surfactant, an emulsifier is used (TU 6-14-1035-79) containing esters of tall oil acids and triethanolamine or the base of the emulsifier Neftenol NZ (TU 2483-007-17197708-93) containing esters of tall oil acids and triethanolamine with esters of tall oil acids and hydroxyethylated alkylamine.

 2. Hydrocarbon solvent - low-hardening fractions of a naphthenoaromatic base, commodity medium distillate fuels or light oils: arctic diesel fuel according to GOST 305-82, jet fuel, for example, grade TS-1 according to GOST 10227-86, transformer oil VG (TU 38-401978-98 ), TC according to GOST 982-68 (GOST 10121-76).

 3. Additives.

 4. Organobentonite or bentonite clay modified with Quaternary ammonium salt (HOUR), water and calcium chloride are used as additives.

 5. The addition of organobentonite is 3.6-10.8 wt.%.

 6. The addition of bentonite clay, a modified Quaternary ammonium salt (HOUR) is 3.6-11.5 wt.%, Including bentonite 2.4-7.2 wt.% and HOUR (for example: hydrophobizer neftenol GF) 1.2-4.3 wt.%, respectively.

 7. The addition of calcium chloride is 1.0-3.4 wt.%.

 8. The addition of water is 2.0-6.8 wt.%.

 Signs 1 and 2 are common with the prototype, and signs 3-8 are essential distinguishing features of the invention.

SUMMARY OF THE INVENTION
Offered:
1. An invert emulsion emulsifier containing an oil-soluble surfactant and a hydrocarbon solvent, characterized in that it additionally contains water, calcium chloride and a solid phase - organobentonite, and as an oil-soluble surfactant - an emulsion - tall oil acid esters of triethanolamine or emulsifier base Neftenol NZ - a mixture of tall oil acid esters and triethanolamine with tall oil acid esters and hydroxyethylated alkylamine, in the following oshenie components, wt.%:
Oil-soluble surfactant (emulsifier or base emulsifier Neftenol NZ) - 20.0-40.0
Calcium Chloride - 1.0-3.4
Water - 2.0-6.8
Organobentonite - 3.6-10.8
Hydrocarbon solvent - Up to 100.0
2. An invert emulsion emulsifier containing an oil-soluble surfactant and a hydrocarbon solvent, characterized in that it further comprises water, calcium chloride and a solid phase - bentonite clay modified with a quaternary ammonium salt, and as an oil-soluble surfactant - an emulsion - complex tall oil acid esters of triethanolamine or emulsifier base Neftenol NZ - a mixture of tall oil acid esters of triethanolamine and tall oil acid esters and ethoxylated alkylamine, in the following ratio, wt.%:
Oil-soluble surfactant (emulsifier or base emulsifier Neftenol NZ) - 20.0-40.0
Calcium Chloride - 1.0-3.4
Water - 2.0-6.8
Bentonite clay - 2.4-7.2
Quaternary ammonium salt (HOUR) - 1.2-4.3
Hydrocarbon solvent - Up to 100.0
For research were used:
1. As an oil-soluble surfactant - emulsion (TU 6-14-1035-79) - esters of tall oil acids and triethanolamine or the base of the emulsifier Neftenol NZ (TU 2483-007-17197708-93) - a mixture of esters of tall oil acids and triethanolamine with esters of tall oil acids and hydroxyethylated alkylamine. The products are dark brown mobile liquids with a density of 940-1000 kg / m ³ , pour point (-10) - (-20) ^o С, acid number 10-20 mg KOH / g, interfacial tension of a 1% solution in diesel fuel at the border with distilled water, 2.0-3.0 mN / m.

 2. As a hydrocarbon solvent, low-hardening fractions of a naphthenoaromatic base, commodity medium distillate fuels or light oils: arctic diesel fuel according to GOST 305-82, jet fuel, for example, grade TS-1 according to GOST 10227-86, transformer oil VG (TU 38-401978 -98), TC according to GOST 982-68 (GOST 10121-76).

 3. As modified clay - organobentonite according to TU 2458-1719708-00 (TU 095-003-11475315-2000).

4. As clay - bentonite clay powder according to TU 39-01-08-658-81 with a solution yield of at least 10 m ³ / t and an exchange capacity of at least 80 mEq per 100 g of clay.

5. As organic modifiers, oleophilizers of bentonites, quaternary ammonium salts are used - alkyltrimethylammonium, alkylbenzyldimethylammonium and dialkyldimethylammonium chloride or alkylpentamethylpropyleneammonium dichloride with at least C ₁₂ alkyl radicals, for example: Hydrophobizator-70-7F-7-UFN-70-N-70-N-70-N-T-7-Nefenolate, for example: alkylbenzyldimethylammonium chloride, see table. 3.

HOUR - substances of an ionic nature, similar to alkali metal salts, contain a positively charged nitrogen atom bonded by four covalent bonds to organic radicals or atoms and one bond to anions. The hydrophilic group is a quaternary nitrogen atom, and the hydrophobic group is hydrocarbon and other radicals. Typical HOUR formula: [R ₄ N] ⁺ Cl ^- . The structure and size of the molecules of these substances correspond to the size of the interpackage layers of the clay mineral lattice, which facilitates their penetration and fixation in the material and the latter's swelling.

В результате адсорбционного и расклинивающего действий КПАВ внедряются в межпакетное пространство слоистого алюмосиликата, вытесняя оттуда обменные катионы с одновременной их адсорбцией на освобожденную поверхность частицы, разрыхляя его кристаллическую решетку и увеличивая его общую пористость.Surface modification of clay minerals HOURs is carried out according to the following scheme:

As a result of the adsorption and proppant actions, the surfactants are introduced into the interpackage space of the layered aluminosilicate, displacing exchange cations from there with their simultaneous adsorption onto the liberated surface of the particle, loosening its crystal lattice and increasing its total porosity.

Subsequently, the inner surface of the mineral becomes accessible for the penetration of non-polar hydrocarbons, causing dispersion of bentonite and an increase in the number of structure-forming elements per unit volume with the subsequent formation of organogel. For these purposes, it is advisable to use QAS with one or two radicals with the number of carbon atoms C ₁₂ -C ₁₈ , or with a total carbon content of about 40 (for alkylaryl derivatives) as modifiers. If organic radicals occupy more than 50% of the mineral’s surface, then adjacent alumina layers cannot come closer to a distance less than two diameters of the n-alkyl chain. The greater the possibility of separation and separation of clay layers, the higher the thickening ability of their organo-derivatives in hydrocarbons. This explains the minimum length of a hydrocarbon radical; an increase in its length above 18 leads to a decrease in the solubility of HOURs. For research, the HOUR properties were used, which are given in table. 3-5.

For research were used:
6. Calcium chloride GOST 450-77.

 7. Water.

8. For the preparation of emulsions — West Siberian formation water, calcium-chloride type, with a density of 1.012 g / cm ³ and a content of Ca ⁺⁺ and Mg ⁺⁺ cations of 1000 mg / L.

 Examples 1-4 describe the technology for obtaining the commercial form of the emulsifier Neftenol NZb and the physicochemical properties of emulsifiers.

 Examples of the preparation of compounds.

Example 1 (composition 2)
30 g of emulsal (a mixture of esters of oleic, linolenic, resin acids - tall oil and triethanolamine) was placed in a beaker, produced according to TU 6-14-1035-79. In this case it was used emultal containing 4% palmiattrietanolamina, stearattrietanolamina 18%, 51% oleattrietanolamina, 9% linoleattrietanolamina, linolenattrietanolamina 7%, 7% triethanolamine ester acid C _{20 to} C _24, 4% carbon impurities character), heated to 40 ^o C, and a hydrocarbon solvent heated to 60 ^° C was poured with stirring (51.5 g TC-1). Without stopping stirring, 9.1 g of organobentonite was added, which was dispersed for 30 minutes, then 9.1 g of an aqueous solution of calcium chloride (3.0 g of calcium chloride dissolved in 6.1 ml of water) was added, the mixture was stirred for 10 -15 minutes before the formation of a homogeneous product, after which the composition was ready for use. The resulting emulsifier Neftenol NZb was a viscous brown liquid with a density of 920-931 kg / m ³ , pour point - 40 ^o C.

Example 2 (composition 7)
3.0 g of ChAC (ARQUAD 2C-75) was charged into a three-necked reactor equipped with a stirrer, reflux condenser and thermometer, and 6.1 ml of water and 21.5 g of hydrocarbon solvent TC-1 were introduced with stirring until the HOUR was completely dispersed. Then 6.1 g of bentonite was introduced into the reactor and stirred for 2 hours at a temperature of 70-90 ^o C. 3.0 g of calcium chloride, previously dispersed to a homogeneous state, were added to the resulting product, 30.0 g of a hydrocarbon solvent in the remainder TS-1, 30.0 g of an oil-soluble surfactant-emulsion (see example 1). The mixture was stirred for 10-15 minutes until a homogeneous product was formed, after which the composition was ready for use.

The resulting emulsifier Neftenol NZb was a viscous brown liquid with a density of 920-930 kg / m ³ , pour point - 40 ^o C.

Example 3 (composition 11)
40.0 g of the base of the Neftenol NZ emulsifier (TU 2483-007-17197708-93) - esters of tall oil acids and triethanolamine, esters of tall oil acids and hydroxyethylated alkylamine were placed in a beaker. In this case, the base of the Neftenol NZ emulsifier was used with a density of 940 kg / m ³ , pour point - 20 ^o С, acid number of 20.2 mg KOH / g and interfacial tension of a 1% solution in diesel fuel at the border with distilled water 2.8 mN / m. The emulsifier was heated to 40 ^° C and the hydrocarbon solvent TC-1 (39 g) heated to 60 ^° C was poured with stirring. Without stopping mixing, 10.8 g of organobentonite was added, which was dispersed for 30 minutes, then 10.2 g of an aqueous solution of calcium chloride (density 1320 kg / m ³ ) was added, the mixture was stirred for 10-15 minutes until a homogeneous product was formed, after which the composition was ready for use.

The resulting emulsifier Neftenol NZb was a viscous brown liquid with a density of 910-920 kg / m ³ , pour point - 40 ^o C.

Example 4 (composition 12)
12.0 g of HOUR (ARQUAD 2C-75) were charged into a three-necked reactor equipped with a stirrer, reflux condenser and thermometer, and 20.0 ml of water and 20.0 g of hydrocarbon solvent (transformer oil) were introduced with stirring until the HOUR was completely dispersed. Then, 24.0 g of bentonite was introduced into the reactor and stirred for 2 hours at a temperature of 70-90 ^o C. 10.0 g of calcium chloride were added to the obtained product, and 714.0 g of a hydrocarbon solvent preliminarily dispersed to a homogeneous state in the remainder ( transformer oil) 200.0 g of an oil-soluble surfactant - the base of the Neftenol NZ emulsifier (TU 2483-007-17197708-93) - tall oil acid esters of triethanolamine, tall oil acid esters and hydroxyethylated alkylamine (see example 3). The mixture was stirred for 10-15 minutes until a homogeneous product was formed, after which the emulsifier was ready for use.

The resulting emulsifier Neftenol NZb was a viscous brown liquid with a density of 880-900 kg / m ³ , pour point - 40 ^o C.

 Other emulsifier formulations were prepared in a similar manner.

The compositions of the proposed emulsifier invert emulsions and emulsifier of the prototype are presented in table. 1. The prepared emulsifiers were evaluated for sedimentation stability at positive and negative temperatures (20 and -40 ^o C). In the compositions of emulsifiers with a low content of organoclay (less than 3.6%), separation occurs with the precipitation of the solid phase and the evolution of the hydrocarbon phase (see composition 4, table 1).

 The increase in the emulsifier water content of more than 6.8% and the solid phase of more than 11.0% (organoclay or bentonite and HOUR) leads to a sharp thickening of the compositions at both positive and negative temperatures, which negatively affects the manufacturability of the emulsifier (see composition 5, table 1).

 Test examples of the proposed compositions of emulsifiers.

 Invert emulsions were prepared as follows. When mixing the calculated amount of emulsifier, the calculated amount of diesel fuel or oil was first introduced, then the calculated amount of produced water. Mixing time 15-20 minutes The result is a stable water-in-oil emulsion.

 Example A. Obtaining an invert emulsion and determining its technological parameters. In the calculated amount of emulsifier (4.0 ml - Neftenol NZb, example 1), 20 ml of diesel fuel was first introduced with stirring, then 76 ml of produced water. Mixing time 15-20 minutes

Emulsions of a different composition were prepared in a similar way (When preparing emulsions on Neftenol NZ (according to the prototype), 4.0 ml of Neftenol NZ, 20 ml of diesel fuel, 73 ml of produced water and 3 ml of an aqueous solution of calcium chloride, calculated concentration) were taken. For the finished emulsion, the electrical breakdown voltage was measured on an IGER-1 (or Fann 23C) device, rheological properties were measured on a VSN-3 rotational viscometer according to the instructions for the device. To measure thermal stability, the finished emulsion was poured into a test tube, filled by 3/4, closed with a ground stopper, and placed in a thermostat adjusted to the required temperature (70-100 ^o С). The emulsion withstood the test of thermal stability (90 ^o C), if for a period of 8 hours there was no allocation of water droplets.

 The research results of the technological parameters of invert emulsions are given in table. 2.

Given in the table. 2, the experimental data indicate that invert emulsions obtained with the Neftenol NZb emulsifier (both for oil and diesel fuel):
- more aggregatively stable (voltage breakdown on the device IHER-1 more than 200 V, while the prototype 15-17 no more than 150 V),
- more thermostable, emulsions on Neftenol NZb at the same concentration of emulsifier have a heat resistance of more than 5 days, while emulsions on Neftenol NZ do not stand the test (less than 8 hours, see 16-17, Table 2),
- the rheological indicators of emulsions based on Neftenol NZ (prototype) sharply decrease with increasing temperature, the rheological indicators of emulsions on the proposed emulsifier have higher values and practically do not change in reservoir conditions, and higher rates of dynamic shear stress increase the efficiency of such emulsions.

 It is necessary to note the best technological indicators for emulsions obtained on the basis of emulsifiers with bentonite clay, modified quaternary ammonium salt, compared with the finished organobentonite (see examples 6-8 and 12-14 of table 2), which is explained by the receipt of a more highly dispersed oleophilic clay in the process of its synthesis in a water-in-oil emulsion.

In the table. 3-5 show the physico-chemical characteristics of HOUR, which were used for research. The use of various types of HOURs with hydrocarbon radicals from C ₁₂ to C ₁₈ makes it possible to obtain effective emulsifiers (see Table 6, which shows the values of the electrical breakdown voltage measured on the IGER-1 device for invert emulsions obtained in Example A for oil), the most effective ones are obtained on the basis of dialkyldimethylammonium chlorides. An increase in the concentration of clay and HOUR above the proposed values does not increase the aggregative stability of the emulsifier (see example 33, 34, composition 31, 32 of table 6), in addition, this leads to thickening of the emulsifier. The decrease in the concentration of clay and HOUR below the proposed values leads to a decrease in aggregative and sedimentation stability - loss of clay (example 5, composition 4, table. 2).

 To increase oil recovery emulsifier is used as follows. After applying the development method by applying water to the formation through the buffer valve of the injection well, the calculated amount of emulsion or emulsifier with oil is pumped into the waterflood at a volume ratio (1: 3-9) in an amount in which there is a decrease in well injectivity to a predetermined mark. After injection of the composition into the reservoir, water or an aqueous polymer solution is injected.

Sources of information
1. Kister E.G. and others. Emulsifier invert emulsion drilling fluids. - Drilling, 1974, 12, pp. 15-18, analogue.

 2. RF patent 2140815, B 01 F 17/00, 17/16, 1999 - analogue.

 3. RF patent 2062142, B 01 F 17/34, 17/40, 17/42, C 09 K 7/06, 1996 - prototype.

Claims (1)

1. An invert emulsion emulsifier containing an oil-soluble surfactant and a hydrocarbon solvent, characterized in that it additionally contains water, calcium chloride and a solid phase - organobentonite, and as an oil-soluble surfactant - an emulsion - tall oil acid esters of triethanolamine or emulsifier base Neftenol NZ - a mixture of tall oil acid esters and triethanolamine with tall oil acid esters and hydroxyethylated alkylamine, in the following oshenie components, wt. %:
Oil-soluble surfactant (emulsifier or emulsifier base Neftenol NZ) - 20.0 - 40.0
Calcium Chloride - 1.0 - 3.4
Water - 2.0 - 6.8
Organobentonite - 3.6 - 10.8
Hydrocarbon solvent - Up to 100.0
2. An invert emulsion emulsifier containing an oil-soluble surfactant and a hydrocarbon solvent, characterized in that it further comprises water, calcium chloride and a solid phase - bentonite clay modified with a quaternary ammonium salt, and as an oil-soluble surfactant - an emulsion - complex tall oil acid esters of triethanolamine or emulsifier base Neftenol NZ - a mixture of tall oil acid esters of triethanolamine and tall oil acid esters and ethoxylated alkylamine, in the following ratio, wt. %:
Oil-soluble surfactant (emulsifier or emulsifier base Neftenol NZ) - 20.0 - 40.0
Calcium Chloride - 1.0 - 3.4
Water - 2.0 - 6.8
Bentonite clay - 2.4 - 7.2
Quaternary ammonium salt (HR) - 1.2 - 4.3
Hydrocarbon solvent - Up to 100.0

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