RU2492214C2 - Method to dehydrate bituminous oils - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the method of bituminous oil dehydration at oil fields with water content of up to 60%, in which for improvement of water separation a hydrocarbon dissolvent is used, such as liquid butanes under the following conditions: volume ratio of liquid butanes (hydrocarbon dissolvent); watered oil (0.5-1):1, temperature 15-20°C, pressure 5-7 kg/cm².

EFFECT: quality of dehydrated oil corresponds to GOST R 51858-2002.

1 dwg, 1 tbl

Description

The invention relates to the oil industry, in particular to methods for dehydration of high-viscosity bituminous oils in oil fields.

Bituminous oils according to GOST 51858-2002 include oils with a density of more than 895 kg / m ³ at 20 ° C / 1 /.

Bituminous oils are extracted using steam, steam is injected into the well, so crude bituminous oil comes from the well with a high emulsion water content of up to 60% of the mass. The high content of resins, asphaltenes (natural emulsifiers) promotes the formation of a water-in-oil emulsion (dispersion medium-oil, dispersed phase-water).

The primary preparation of oil in the oil fields is usually carried out by thermochemical dehydration in the presence of a demulsifier or electrochemical dehydration / 2, 3 /.

For dehydration of high-viscosity bituminous oils, thermochemical dehydration is not effective, and electrochemical methods cannot be used due to the high water content. When using the electrochemical method, a high water content leads to the closure of the electrodes, usually with an electrochemical dehydration, the water content does not exceed 10% / 2 /.

The densities of water and bituminous oils are close in value, which makes it difficult to sediment oil in a gravitational field. To reduce the density of tar oils and improve sludge in the gravitational field, hydrocarbon diluents are used.

The closest in technical essence to the present invention and selected by the authors as a prototype is the "Method of desalination and dehydration of heavy viscous oil and trap oil" / 4 /, which use light oil or gasoline to dilute heavy viscous oil.

The use of light oils (density 830-850 kg / m ³ , GOST 51858-2002) or gasolines (density 700-800 kg / m ³ ) is not efficient enough for dilution of flooded bituminous oils with oil, the density of bituminous oil decreases from 945-970 kg / m ³ to 886-919 kg / m ³ , the emulsion is divided into only 50-60%, the residual water content is 24-30%.

In addition, the method / 4 / provides for the use of electric desalination plants, the high content of emulsion water in flooded bituminous oils excludes the use of electric desalination plants due to the closure of the electrodes.

The technical result of the invention is the dehydration of high-viscosity bituminous oils with an emulsion water content of up to 60% in oil fields and bringing the content of water, chloride salts and solids to the norm according to GOST R 51858-2002. Oil.

The technical result is achieved by mixing liquid butanes (hydrocarbon diluent) with flooded high-viscosity bituminous oil under the following conditions:

volumetric multiplicity liquid butanes (hydrocarbon diluent): watered oil (0.5-1): 1, temperature, ° С 15-20 pressure, kg / cm ² 5-7

The present invention is considered on the example of the processing of bituminous oil deposits of the Komi Autonomous Soviet Socialist Republic, Yarega oil.

Physico-chemical properties of Yarega oil / 2 /:

Density, 20 ° С, kg / m ³ 945 Viscosity, 40 ° С, mm ² / s 86.3 Pour point, ° C minus 10 Flash point in a closed crucible, ° С 108 The content of paraffins,% mass 1.4 The content of sulfuric acid resins,% more than 50 Coking ability,% 8.44 Sulfur content,% 1,11 The yield of fractions,%: up to 200 ° C 0.4 up to 350 ° C 18.8

When mixing highly flooded high-viscosity bituminous Yarega oil with liquid butanes (hydrocarbon diluent), the oil density decreases from 945-970 kg / m ³ to 800-850 kg / m ³ (the initial density of liquid butane is 488-500 kg / m ³ ).

The experiment was conducted on a flow-through pilot installation on Yaregskaya oil samples with a density of 945-970 kg / m ³ and a water content of 55-60% by weight. Temperature and volumetric multiplicity liquid butanes (hydrocarbon diluent): watered oil is selected in such a way that the emulsion is destroyed, oil is separated from water, but asphaltene precipitation is not yet observed. As a result, the quality of the dehydrated oil complies with GOST R 51858-2002 for oil for delivery to transport organizations and enterprises (table).

Table Quality indicators of dehydrated Yarega oil and requirements in accordance with GOST 51858-2002 Norm for oil of the GOSTR 51858-2002 group Quality indicators Name of indicator one 2 3 dehydrated Yareg oil 1 Mass fraction of water,%, no more 0.5 0.5 1,0 Up to 0.5 2 Mass concentration of chloride salts, mg / dm ³ , no more one hundred 300 900 Up to 30 3 Mass fraction of mechanical impurities,%, no more 0.05 Up to 0.05

A schematic diagram of a pilot plant for the dehydration of bituminous oil using liquid butanes as a hydrocarbon diluent is shown in the figure. Watered bituminous oil, if necessary, is heated in the oil heater 1, and then mixed with liquid butanes. A mixture of oil and liquid butanes by pump 2 is fed to the sump 3, where the main amount of water is separated. Next, the mixture is sent to a filter-coalescer 4 to separate liquid-liquid systems, after which the dehydrated oil is sent to a column 5 for stripping butanes. In column 5, dehydrated bituminous oil is separated from liquid butanes, which are again fed to the dehydration process. In the reflux tank 7, water condensed after cooling in the air cooling apparatus (ABO) 6 is additionally separated.

If the content of chloride salts in the dehydrated oil is exceeded, washing water in an amount of 2-5% per mixture of oil and liquid butanes is fed into the mixture of oil and liquid butanes before the filter-coalescer 4. Dehydrated oil is pumped out by pump 8.

Literature

1. GOST R 51858-2002, Oil, General specifications.

2. Oil refinery reference. Edited by G.A. Lastovkina, E.D. Radchenko and M.G. Rudina. - L .: Chemistry, 1986.- 648 p.

3. Oil field preparation. V.P. Tronov, Feng (Science) of the Academy of Sciences of Tatarstan. 2000 year

4. Kuzora I.E. et al. Method for desalting and dehydrating heavy viscous oil and trap oil. Application for invention 2002124409/04, 09/12/2002. Application publication date 03/20/2004. Patent RU 2230771.

Claims (1)

A method of dehydration of oils, including mixing with a hydrocarbon diluent, characterized in that they are used to dehydrate bituminous oils with a water content of up to 60%, liquid butanes are used as a hydrocarbon diluent to reduce the density of bituminous oils and improve gravity sludge, the process is carried out under the following conditions:
volumetric multiplicity liquid butanes (hydrocarbon thinner): waterlogged oil (0.5-1): 1 temperature, ° С 15-20 pressure, kg / cm ² 5-7

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