RU2165953C1 - Composition for removing asphaltene-tar-paraffin deposits - Google Patents

Abstract

FIELD: oil and gas production. SUBSTANCE: composition suitable for removing asphaltene- tar-paraffin deposits from bottom zone of formation, exhaust lines, oil- gathering collectors, and oil-field equipment contains, vol. %: aliphatic hydrocarbons, 25-85; polar nonelectrolyte, 2-5; nonionic surfactant, 1-2; cationic surfactant (object of invention), 1-2; and aromatic hydrocarbons, the balance. EFFECT: increased resistance of composition against hydrocarbon-oxidizing bacteria. 3 tbl

Description

 The invention relates to the field of oil production, in particular to compositions for removing asphaltene-tar-paraffin deposits (paraffin deposits), and can be used to remove paraffin deposits from the bottomhole formation zone, flow lines, oil reservoirs and oilfield equipment for oil producing and oil refining enterprises.

 Known composition for the removal of paraffin, containing hexane and ethylbenzene fraction (/ 1 / ed. St. USSR N 1620465).

 A disadvantage of the known composition is the insufficiently high efficiency of the removal of paraffin.

 The closest to the proposed technical solution in terms of technical nature and the effect achieved is a composition for the removal of paraffin deposits, containing, vol.%: Aliphatic 45-85 and aromatic hydrocarbons 5-45, polar nonelectrolyte 1-15 and nonionic surfactant 0 5-6 (/ 2 / US 4090562).

 However, this composition does not provide a high degree of paraffin removal and is capable of undergoing biodegradation under the influence of oil field bacterial microflora.

 The problem solved by the invention is to increase the efficiency of the composition relative to the destruction of paraffin deposits and increase the biostability of the proposed composition to the effects of hydrocarbon-oxidizing bacteria (BOD), which destroy the molecular structures of the hydrocarbons that make up the composition.

The problem is solved in that the known composition for the removal of paraffin, containing aliphatic and aromatic hydrocarbons, polar non-electrolyte and nonionic surfactants, additionally contains a cationic surfactant, in the following ratio of ingredients, vol.%:
aliphatic hydrocarbons - 25-85
polar non-electrolyte - 2-5
nonionic surfactant - 1-2
cationic surfactant - 1-2
aromatic hydrocarbons - the rest.

To obtain the proposed composition used the following substances:
- aliphatic hydrocarbons - hexane (TU 6-09-3375-78), petroleum ether (TU 6-02-1244-83);
- aromatic hydrocarbons - nefras A 130/150 (GOST 10214-78);
- polar non-electrolyte - bottoms residue produced by butyl alcohols (TU 38.10216785), butanol-1 (GOST 5208-81);
- nonionic surfactant - ethoxylated alkyl phenol AF _9-12 block copolymer of ethylene and propylene oxides Progalit NM 20/40;
- cationic surfactants (quaternary ammonium salts) - alkyl (C ₁₄ -C ₁₇ ) trimethylammonium chlorides and dialkyl (C ₁₂ -C ₁₄ ) dimethylammonium.

 An example of the preparation of the proposed composition in laboratory conditions is discussed below.

Example. In a flask with a capacity of 250 ml, 1 ml of ethoxylated alkylphenol AF _9-12 , 2 ml of alkyl (C ₁₄ -C ₁₇ ) trimethylammonium chloride oily consistencies, 2 ml of bottoms from the production of butyl alcohols and 70 ml of nephras A 130/150 are successively poured. Thoroughly mix the resulting mixture by shaking until the ingredients are completely dissolved. Then an additional 25 ml of hexane is added to the flask. Close the flask with a ground stopper and mix the contents by shaking. Get a solution with the following ratio of ingredients, vol.%: Aliphatic hydrocarbon - hexane - 25; aromatic hydrocarbon - nefras A 130/150 - 70; polar non-electrolyte - bottom residue of butyl alcohol production - 2; nonionic surfactant - ethoxylated alkyl phenol AF _9-12 - 1, a quaternary ammonium base salt - alkyl chloride (C ₁₄ -C ₁₇ ) trimethylammonium - 2.

 In a similar way, preparations were prepared with a different ratio of ingredients (Table 1).

 Data on the composition of the investigated paraffin are given in table. 2.

 The inventive composition was tested for the effectiveness of the destruction of the structure of paraffin deposits according to the following method.

For testing a sample of paraffin, the characteristics of which are given in table. 2, stuffed into a polyethylene syringe with a diameter of 10 mm, squeezed out and weighed the obtained cylindrical paraffin mold weighing about 2 g. Then it was placed in a pre-weighed cylindrical stainless steel basket with a mesh size of 1x1 mm. The size of the basket is 20x15x15 mm. The initial mass of the AFS (m ₀ ) was determined by the difference in the masses of the baskets with paraffin and pure baskets. Then the basket was placed in an airtight flask and filled with the composition in the mass ratio of paraffin: solvent = 1:10. Maintained at a temperature of 20 ^o C for 2 hours. After this time, the basket was removed, placed in a desiccator connected to a water-jet pump. Produced a drying of the ARPD sample at a residual pressure of 2-3 mm Hg. to constant weight. The mass difference between the baskets with paraffin and the clean baskets was used to determine the mass of the remaining paraffin deposits (m ₁ ). The destruction efficiency of the AFS structure (E,%) was calculated by the formula:
E = (m ₀ - m ₁ ) 100 / m ₀ ,%
The results are shown in table. 3.

The data given in table. 3 show that the introduction into the claimed composition of a cationic surfactant, in particular, alkyl (C ₁₄ C ₁₇ ) trimethylammonium and dialkyl (C ₁₂ -C ₁₄ ) dimethylammonium chlorides, in an amount of 1-2 vol.% Increases the destructive ability of the composition with respect to paraffin by 2-33%. The introduction of a cationic surfactant, in particular, alkyl (C ₁₄ -C ₁₇ ) trimethylammonium chloride, in an amount of 3 vol.% Does not improve the destructive ability of the composition with respect to paraffin deposits.

 Hydrocarbon-oxidizing bacteria, in particular microorganisms of the genus Pseudomonas, are widespread in oil reservoirs (/ 3 / ROZANOVA E.P. et al. Microflora of oil fields, M, Nauka, 1974). Under their influence, hydrocarbons of an oil deposit undergo biodegradation and oxidation. In aliphatic hydrocarbons, under the influence of DRR, the terminal methyl group or the methylene group closest to it is oxidized. Oxidation proceeds along a common biological pathway - from alcohol to acid. Microbiological dehydrogenation of aliphatic hydrocarbons was noted. The destruction of DRR aromatic compounds occurs by rupture of ring structures. Cleavage is preceded by the formation of structures with hydroxyl groups. Aromatic hydrocarbons with side chains are most easily oxidized.

 Organic solvents based on aliphatic and aromatic hydrocarbons during storage and use in oil production processes under the influence of DRR are able to change their technological properties. The introduction of cationic surfactants into the composition of solvents can prevent a violation of the technological properties of the compositions under the influence of DRR by suppressing their vital functions.

 The effectiveness of the DRR suppression by the proposed composition was established according to RD 39-3-973-83 (/ 4 / RD 39-3-973-83 "Methodology for controlling the microbiological contamination of oilfield waters and evaluating the protective and bactericidal action of reagents", Ufa, VNIISPTneft, 1984) in following sequence.

Into labeled penicillin vials with Raymond's nutrient medium (5 ml), 0.5 ml of the DRR accumulation culture isolated from the oilfield media of Yuganskneftegaz OJSC was introduced. There was added 5 ml of the composition (table. 1) to remove the paraffin. The contents of the flasks were mixed and placed in a thermostat at a temperature of 32 ^o C for 1 day.

 Three parallel tests were performed for each formulation.

Then, 0.5 ml of the aqueous phase was taken from each flask for sowing the culture and introduced into the 1st penicillin flask with Raymond's nutrient medium. The contents were mixed, 0.5 ml of the sample was taken and introduced into the 2nd penicillin vial with Raymond's nutrient medium - dilution 1:10. This method was used for subsequent dilutions of 1: 100, 1: 1000, 1: 10000, 1: 100000. After seeding, all penicillin vials were incubated at a temperature of 32 ^o C for 15 days.

 The presence of DRR in the samples was established after 15 days by clouding of the nutrient medium in the seed bottles. The content of DRR in the aqueous layer in contact with the composition for the removal of paraffin is presented in table. 3.

As can be seen from the table. 3 data, the introduction into the claimed composition of a cationic surfactant, in particular, alkyl (C ₁₄ -C ₁₇ ) trimethylammonium and dialkyl (C ₁₂ -C ₁₄ ) dimethylammonium chlorides in an amount of 1-2 vol.% Leads to the suppression of the vital activity of DRR developing at the border water-hydrocarbon contact. Either a complete suppression or a decrease in the number of DRR by a factor of 10,000 is observed.

The introduction of a cationic surfactant, in particular, alkyl (C ₁₄ -C ₁₇ ) trimethylammonium chloride, in an amount of 0.5 vol.% Reduces the number of DRR by only 100 times.

Thus, the claimed composition has the following advantages compared with the known prototype composition:
- increases the destructive ability of the composition in relation to paraffin by 2-33%;
- provides its biostability against hydrocarbon-oxidizing bacteria.

Claims (1)

Composition for removing asphaltene-resin-paraffin deposits, containing aliphatic and aromatic hydrocarbons, polar non-electrolyte and nonionic surfactant, characterized in that it additionally contains a cationic surfactant in the following ratio of components, vol.%:
Aliphatic hydrocarbons - 25 - 85
Polar non-electrolyte - 2 - 5
Nonionic Surfactant - 1 - 2
Cationic Surfactant - 1 - 2
Aromatic Hydrocarbons - Else

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