RU2326153C1 - Inhibitor of paraffin deposits - Google Patents

Abstract

FIELD: oil and gas producing industry.

SUBSTANCE: invention is referred to the field of development and operation of the oil-fields complicated by formation of asphalt-gum-paraffin deposits. Inhibitor of paraffin deposits for paraffin oil contains, mass %: amides of synthetic fat acids of fraction C_21-25 and polyethylene polyamines - dopant DP-65 25.0-75.0 and ethers of synthetic fat acids of fraction C_21-25, pentaerythritol and phthalic anhydride - dopant TumII-77 25.0-75.0.

EFFECT: increase of inhibition extent of paraffin deposits.

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Description

The invention relates to the field of development and operation of oil fields, complicated by the formation of asphalt-resin-paraffin deposits.

Paraffin scale inhibitors are used to reduce paraffin formation in oil production. As inhibitors of paraffin deposits, a copolymer of acrylic and methacrylic acids (DN-1 additive), ethylene vinyl acetate copolymers (VES 501 additive), a condensation product of synthetic fatty acids and triethanolamine in kerosene (Azolyate-7 additive), block copolymers of hydroxyalkylated alkyl phenols are used. and ethylenediamine, foreign inhibitors of the company Nalko and Servo-Champion, foreign inhibitor XT-48, etc. [Olenev L.M. New domestic paraffin inhibitors. - M .: VNIIOENG, 1990. - 51 p.].

There is also a method of inhibiting paraffin using an additive TyumII-77 [Agaev S.G. et al. Obtaining experimental batches of depressant additives TyumII-77M. Chemistry and technology of fuels and oils, 1994. - No. 9-10. - S.10-11]. Additive TyumII-77 is an ester of synthetic fatty acids (FFA) fraction C _21-25 , pentaerythritol (PE) and phthalic anhydride (FA) [1. A.S. USSR 1049524, С10М 1/26, 1983. 2. Agaev S.G. et al. Obtaining experimental batches of depressant additives TyumII-77M. Chemistry and technology of fuels and oils, 1994. - No. 9-10. - S.10-11]. Additives are obtained by the interaction of FFA, pentaerythritol and phthalic anhydride with their molar ratio, respectively (1.2-2.7): 1.0: (0.8-1.0). The esters of FFA, PE, and FA are effective as paraffin inhibitors with a content of 0.05–2.0 wt% [Agaev SG, Berezina Z.N., Khalin AN Inhibition of the process of waxing wells and oil pipelines. // Oilfield business. - 1996. - No. 5, p.16-17].

Closest to the claimed invention in terms of features is a method of inhibiting paraffin deposits in the presence of the additive DP-65 [Agaev SG, Berezina Z.N., Khalin A.N. Inhibition of the process of waxing wells and oil pipelines. // Oilfield business. - 1996. - No. 5, p.16-17]. Additive DP-65 is an amide of synthetic fatty acids (FFA) of fraction C _21-25 and polyethylene polyamines (PEPA) [RF Patent 2106395, C10M 149/14, 149/22, 1998]. Amides of FFA and polyethylene polyamines are effective as paraffin inhibitors with their content of 0.01-0.2 wt.%.

Amides of synthetic fatty acids and polyethylene polyamines are not sufficiently high inhibitory ability of paraffin deposits.

The task to be solved by the claimed method is aimed at improving the inhibitory properties of pentaerythritol esters and polyethylene polyamine amides.

The problem can be solved by achieving a technical result, which consists in increasing the degree of inhibition of paraffin deposits.

The indicated technical result is achieved by the fact that the paraffin inhibitor for preventing the formation of paraffin deposits, containing amides of FFA C _21-25 fraction and polyethylene polyamines - additive DP-65, additionally contains esters of synthetic fatty acids of fraction C _21-25 , pentaerythritol and phthalic anhydride - additive Tyumen -77 in the following ratio of components, wt.%: Additive DP-65 - 25.0-75.0, additive TyumII-77 - 25.0-75.0.

The application used the additive DP-65 - amides FFA fraction C _21-25 and polyethylene polyamines obtained with a molar ratio of the starting products, respectively 3.0: 1.0 / USSR 1049524, C10M 1/26, 1983 /. The additive sample was a light brown solid product with an acid number of 9.4 mg KOH / g, with a molecular weight of 920 and a melting point of 68 ° C; the refractive index of the additive at 20 ° C. 1.4750.

The application also used the additive TyumII-77 - esters of synthetic fatty acids (FFA), fraction C _21-25 , pentaerythritol (PE) and phthalic anhydride (FA) with a molar ratio of 2.0: 1.0: 1.0 / RF Patent 2106395, C10M 149/14, 149/22, 1998 /. The additive was a light brown solid product with an acid number of 15 mg KOH / g, the melting point of the additive was about 90 ° C, the saponification number was 260 mg KOH / g, the viscosity of a 20% additive solution in oil at 50 ° C was 93 mm ² / C.

Example. As a high-paraffin product, a 10% solution of ceresin-80 in hexane is taken. Ceresin has the following properties: melting point 79.0; molecular weight 812; the density at 20 ° C of 798.6 kg / m ³ and the content of hydrocarbons that formed a complex with urea, 27 wt.%. Hexane with the following properties was used: Molecular mass 86; density at 20 ° C 655 kg / m ³ ; melting point at 20 ° С - minus 95.3; boiling point 68.7 ° C; refractive index at 20 ° C 1.3722.

Inhibition of paraffin deposits using additives was evaluated on a laboratory setup based on the “cold rod” method [Agaev SG, Berezina Z.N., Khalin AN Inhibition of the process of waxing wells and oil pipelines. // Oilfield business. - 1996. - No. 5. - S.16-17]. The installation is made of glass, with the exception of the cold rod, which is made of steel. The setup provides fast experiments, their reproducibility and selectivity of the deposition of paraffin hydrocarbons.

A 10% solution of ceresin in hexane was used as an oil model. When choosing the initial ceresin, we proceeded from the fact that the physicochemical properties of ceresin are close in chemical composition and other physicochemical properties, in particular, in terms of melting point, to paraffin deposits formed under oilfield conditions.

When selecting hexane simulating liquid petroleum hydrocarbons proceed from its _{heated at} reflux temperature t = 68,7 ° C, which is in the temperature range from the bottom to the mouth for most Western Siberia wells. Water having a boiling point t _boiling point = 100 ° C was used as a hot heat carrier, and ethanol with t _boiling point = 82.4 ° C was used as a cold heat carrier. During the installation, the water was in a boiling state and had a temperature of 100 ° C, and ethyl alcohol had a temperature of 0 ° C. Ethyl alcohol was cooled to zero temperature in a freon refrigerator company "Lauda".

This combination of solvent and coolants ensures the boiling of the oil model in the working space, and therefore, the simulation of the movement of oil, its degassing and diffusion of solid hydrocarbons from the bulk to the surface of the cold rod. The mass ratio of "hot" coolant: the working mixture, taking into account the design capabilities of the laboratory setup, output and characteristics of the resulting software, is taken to be 2.5: 1. Maintaining this ratio unchanged ensures constant heat transfer.

The prepared solution with a certain concentration of ceresin and additives in the solvent is loaded into the internal space of the installation. The unit is equipped with refrigerators for condensation of solvent and heat carrier vapors and is connected by a thin section to a jacket into which a certain heat carrier is poured (in this case, water). The installation is heated by electric stove. At the moment the "solid hydrocarbons in hexane" system boils, the supply of refrigerant (ethanol) begins, which circulates in the inner space of the cold rod.

After the end of the experiment, the cold rod with the formed layer of deposits is carefully removed from the installation. The precipitate from the rod is partially mechanically and partly due to heat treatment (fusion) is transferred into a small beaker. Minor traces of hexane are removed from the precipitate in a vacuum oven. The amount of precipitate formed is determined by the gravimetric method.

Each experiment is carried out several times and the average value of experiments carried out under the same conditions is taken as the result of the experiment.

Inhibition of paraffin deposits was carried out on the described installation under the following conditions: temperature of the hot coolant 100 ° C; temperature of a cold working rod 0 ° С. The temperature gradient between the hot and cold walls was 12.5 ° C / mm. The ceresin content in hexane was 10 wt.%. The loading of ceresin was 2.18 g, the loading of hexane was 19.62 g. The consumption of additives was varied in the range from 0.005 to 0.5% by weight for loading the starting products (total ceresin + hexane). The degree of inhibition of PO was evaluated by the ratio:

where M _about - the mass of deposits of solid hydrocarbons on a cold rod without additives; M _CR - the mass of deposits after the additive.

Table 1 presents the results on the inhibition of paraffin deposits (PO) from a 10% model system of ceresin in hexane in the presence of additives according to the analogue and prototype, i.e. for additives DP-65 and TyumII-77. For comparison, the same table presents the results of inhibition of PO in the presence of other known (commercial) inhibitors of PO [Olenev L.M. New domestic paraffin inhibitors. - M .: VNIIOENG, 1990. - 51 p.].

It is known that PO inhibitors are divided into two groups - inhibitors with a depressant effect and inhibitors with a modifying effect. Both groups of additives lower the pour point of paraffinic oils and petroleum products. But the second group of additives, in addition, lowers the temperature at which crystallization of paraffin hydrocarbons begins in the oil or oil product [Bashkatova S.T. Additives to diesel fuels - M .: Chemistry, 1994. - 256 p.]. In order to clarify the direction of action of the additives used in the work, their depressive and modifying properties were studied. For 10% model ceresin systems in kerosene, cloud _points t _p (crystallization onset temperature) and pour point t _s were determined. The first indicator was determined according to GOST 5066-91, the second - according to GOST 20287-91. The results obtained are presented in table 2. An analysis of the data in this table shows that only two of the seven additives lower the onset of crystallization of ceresin hydrocarbons in kerosene. This is the additive DP-65 and the additive Sepaflux-3153. In the first additive, the effect of lowering the temperature of crystallization onset reaches 19 ° С, in the second - 8 ° С.

Table 3 presents data on the inhibition of software using additive compositions. The compositions were composed of additives that are most effective in depressive ability ( _t.sub.c decreases to subzero temperatures) and additives that are most effective in influencing the crystallization onset temperature. The concentration of the first additives was 0.005%, and the concentration of the second additives was 0.01%. The first group of additives was Visco-5351, Flexoil-WM-1470, DN-1 and TyumII-77. The second group of additives consisted of additives DP-65 and Sepaflux-3153. The main second component of most compositions was the additive DP-65. When choosing it, we proceeded from the fact that this additive to the greatest extent slows down the crystallization processes of high-melting solid paraffin hydrocarbons. To identify the maximum effects, compositions were also compiled from the most effective depressant additives.

The analysis of the results presented in table 3 shows that the accepted principles for the selection of compositions were justified. All compositions, including the additive DP-65 as a second component, were significantly more effective than the components of the composition. The most effective additive compositions are Visco-5351, Flexoil-WM-1470, DN-1 and TyumII-77 in combination with the additive DP-65. The degree of inhibition of these compositions exceeds 81.6%. The degree of inhibition of these additives with their content of 0.005 wt.% Without additives DP-65 does not exceed 54%. Combinations of the most effective additives (in terms of depressive ability) are ineffective with each other, although there is a certain effect of an increase in the degree of inhibition even in the presence of such compositions.

Obviously, the discovered effects of an increase in the degree of inhibition of PO in the presence of the DP-65 additive can be attributed to the ability of the DP-65 additive to slow down the crystallization of ceresin hydrocarbons with decreasing temperature. The first components that make up the compositions are characterized by a high depressant ability with a low oil content, but, obviously, not too high inhibitory ability with respect to the formation of paraffin deposits. Additive DP-65, in turn, has not too high depressant properties, but at the same time, a high inhibitory ability at a high content with respect to the formation of PO. The combination of various properties of the components of the composition of the components leads to a significant positive effect. Obviously, the increased inhibitory effect of the compositions including Sepaflux-3153 additive can be explained in a similar way. The latter additive also has an effect that slows down the crystallization of ceresin hydrocarbons.

The effectiveness of additive compositions as PO inhibitors was evaluated depending on their (compositions) content in a solution of ceresin in hexane. Table 4 presents data for the claimed compositions TyumII-77 + DP-65 and for comparison also for compositions Visco-5351 + DP-65, Flexoil-WM-1470 + DP-65. The ratio of the components for the composition TyumII-77 + DP-65, respectively, was 1.0: 2.0; 1.0: 1.0 and 2.0: 1.0. The ratio of components in other compositions is taken equal to 1.0: 2.0, respectively. The studies were carried out according to the methodology adopted and described earlier. The content of the additive compositions ranged from 0.005 wt.% To 0.5 wt.%.

The results show that the composition of additives TyumII-77 + DP-65, studied in a wide range of ratios and in a wide range of concentrations, showed a fairly high efficiency - more than 71.1-81.6 wt.% At a content of 0.005-0.01 wt. .%. The composition works in a wide range of its contents without failing in effectiveness. The composition of these additives is more effective than its constituent components (compare table 1 and table 4). Visco-5351 + DP-65 and Flexoil-WM-1470 + DP-65 additives are also highly effective. The first composition has a failure in its effectiveness with its content in a solution of ceresin in hexane of 0.1 wt.%. This, obviously, is due to the fact that at this concentration the Visco-5351 additive does not work anymore, and the DP-65 additive does not work yet. The second Flexoil-WM-1470 + DP-65 additive composition is effective in a very narrow range of its contents.

Information sources

1. Olenev L.M. New domestic paraffin inhibitors. - M.: VNIIOENG, 1990. - 51 p.

2. A.S. USSR 1049524, C10M 1/26, 1983.

3. RF patent 2106395, C10M 149/14, 149/22, 1998.

4. Agaev S.G. et al. Obtaining experimental batches of depressant additives TyumII-77M. Chemistry and technology of fuels and oils, 1994. - No. 9-10. - S.10-11.

5. Agaev S.G., Berezina Z.N., Khalin A.N. Inhibition of the process of waxing wells and oil pipelines. // Oilfield business. - 1996. - No. 5. - S.16-17.

6. Bashkatova S.T. Additives to diesel fuels. - M .: Chemistry, 1994 .-- 256 p.

Table 1
Inhibition of paraffin deposits (PO) using depressant additives on a ceresin model (10 wt.%) In hexane №№ Additive The degree of inhibition of PO (%) when the content of additives in a solution of ceresin in hexane, wt.% 0.005 0.0075 0.01 0.015 0.05 0.1 0.5 one DP-65 -15.8 25.3 50,0 54,4 59.2 75.0 80.2 2 TyumII-77 9.2 34.1 54.0 52.1 56.6 60.5 69.7 3 Sepaflux-3153 - - 61.8 - 64.5 69.7 93,4 four Visco-5351 34.2 - 75.0 - 80.3 31.6 25.0 5 Flexoil-WM-1470 13.6 - 69.7 - 27.6 25.0 -9.2 6 DN-1 - - 55.3 - 76.3 81.6 89.5

table 2
Clouding temperatures t _p and solidification t _s (° C) of model ceresin systems in kerosene, depending on the content of depressant additives Dp Indicators The cloud point t _p , dissolution t _p and solidification t _s (° C) when the additive contains in the model system, wt.% out 0.005 0.01 0.05 0.1 0.5 one 2,5 5 DP-65 t _p 56 55 54 53 51 42 37 38 40 t _s 13 fifteen 22 36 37 2 16 26 26 TyumII-77 t _p 56 56 56 57 56 56 56 56 57 t _s 13 19 eighteen eleven -6 -3 fifteen 16 23 Sepaflux-3153 t _p 56 54 53 53 52 fifty 48 49 fifty t _s 13 13 0 5 fifteen 19 3 26 28 Visco-5351 t _n 56 56 53 55 56 55 55 58 59 t _s 13 fourteen -3 -23 -10 -8 -2 9 10 Flexoil-WM-1470 t _p 56 56 56 57 55 56 56 56 56 t _s 13 -5 -3 -6 17 12 5 6 5 DN-1 t _p 56 56 56 57 56 57 57 58 58 t _s 13 fourteen -eleven -fourteen -8 2 13 eighteen 23

Table 3
Paraffin Deposition Inhibition (PO) Using Depressant Additive Compositions No. p / p DP and composition DP The content of DP, wt.% S _and ,% one Visco-5351 0.005 34.2 2 Flexoil-WM-1470 0.005 13.6 3 DP-65 0.01 50,0 four TyumII-77 0.005 9.2 5 TyumII-77 0.01 54.0 6 DN-1 0.005 44.7 7 VPEA 0.01 34.2 8 Visco-5351 0.005 85.5 DP-65 0.01 9 Flexoil-WM-1470 0.005 84.2 DP-65 0.01 10 TyumII-77 0.005 82.3 DP-65 0.01 eleven TyumII-77 0,075 74.5 DP-65 0,075 12 TyumII-77 0.01 78.3 DP-65 0.005 12 DN-1 0.005 81.6 DP-65 0.01 13 VPEA 0.01 21.1 DP-65 0.01 fourteen Visco-5351 0.005 34.2 TyumII-77 0.01 fifteen Visco-5351 0.005 34.2 16 Flexoil-WM-1470 0.005 13.6 17 Sepaflux-3153 0.01 61.8 eighteen Visco-5351 0.005 68,4 Sepaflux-3153 0.01 19 Flexoil-WM-1470 0.005 60.5 Sepaflux-3153 0.01 twenty Visco-5351 0.005 57.9 Flexoil-WM-1470 0.01

Table 4
Inhibition of paraffin deposits (PO) using depressant compositions on a ceresin model (10 wt.%) In hexane №№ Additive Composition The additive content in the mixture, wt.% The degree of inhibition of PO S _and (%) when the content of DP in the model, wt.% 0.005 0.01 0.015 0.05 0.1 0.5 one TyumII-77 33.3 76.3 81.6 82.3 84.2 - 92.1 DP-65 66.7 2 TyumII-77 50,0 71.1 73.7 74.5 89.5 - 94.7 DP-65 50,0 3 TyumII-77 66.7 74.8 76.3 78.3 79.0 - 94.7 DP-65 33.3 four Visco-5315 33.3 65.8 84.2 85.5 86.8 60,2 97.4 DP-65 66.7 5 Flexoil-WM-1470 33.3 36.8 44.7 84.2 63,2 - 92.1 DP-65 66.7

Claims (1)

Paraffin scale inhibitor for paraffinic oils containing amides of synthetic fatty acids of fraction C _21-25 and polyethylene polyamines - additive DP-65, characterized in that it additionally contains esters of synthetic fatty acids of fraction C _21-25 , pentaerythritol and phthalic anhydride - an additive of TyumII- 77 in the following ratio of components, wt.%: additive DP-65 25.0-75.0 TyumII-77 additive 25.0-75.0