RU2259386C2 - Composition for dehydration, desalting, and improvement of rheological properties of crude oil - Google Patents

Abstract

FIELD: crude oil treatment.

SUBSTANCE: objective of invention is treatment of crude oil before processing, in particular dehydration, desalting of oil, destruction of water-oil emulsions, and improvement of rheological properties to facilitate transportation of oil through crude oil lines. Composition contains 25.0-55.0% of nonionic demulsifier, notably ethylene oxide/propylene oxide block copolymer based on monoethylene glycol with average molecular mass 4300, 5.0-75.0% of diethylene glycol production distillate (including 20.0-40.0% ethylene glycol methyl ether, 30.0-60.0% diethylene glycol methyl ether, 2.0-5.0% methanol, and 15.0-18.0% water), and solvent, preferably methanol (to 100%).

EFFECT: enhanced oil dehydration and desalting efficiency and improved rheological properties of oil.

1 dwg, 2 tbl

Description

The invention relates to the preparation of oil and can be used for dehydration and desalination of oil, as well as in-line oil demulsification to improve the rheological properties of well products and preliminary discharge of produced water.

Known nonionic demulsifier containing block copolymers of ethylene and propylene oxides based on ethylene glycol and propylene glycol-Reapon-4B (see 1. TU 6-55-54-91).

The disadvantage of this demulsifier is the low demulsifying efficiency in the destruction of high-viscosity oils of the coal-bearing horizon, as well as oils containing mechanical impurities. Reapon-4V slightly improves the rheological properties of these types of oil products.

A known composition for dehydration and desalination of an oil emulsion containing a 50-55% aqueous methanol solution of a nonionic block copolymer of ethylene and propylene oxides-Reapon-4B and a polyglycol resin is a waste from the production of ethylene glycols and additionally water in the following ratio of components, wt.%: 50 -55% aqueous methanol solution of a nonionic block copolymer of ethylene and propylene oxides 70-82; waste production of ethylene glycols-polyglycol resin 7-17; water - the rest, (see 2. Patent of the Russian Federation No. 2091435, BI No. 27, 09/27/97.)

The disadvantage of this composite combination of reagents is that this mixture uses an unstable composition and molecular weight distribution waste of the production of ethylene glycols - polyglycol resin. Because of this, both surface-active and rheological parameters of the reduced composition can significantly deteriorate.

The closest to the invention is a composition for dehydration and desalting of oil containing a nonionic demulsifier - a block copolymer of ethylene and propylene oxides based on monoethylene glycol with a molecular weight of 4300 and a solvent (methanol). The composition additionally includes the bottom residue of the production of butyl ethers of monoethylene glycol and diethylene glycol, wt.%: Monoethylene glycol 0.5-4.0, diethylene glycol 0.5-4.0, butyl ether of monoethylene glycol 1.5-13.0, butyl ether of diethylene glycol 9, 5-75.0, a mixture of butyl esters of tri-, tetra- and pentaethylene glycols 0.5-4.0. The ratio of components in the composition, wt.%: Block copolymer of ethylene oxide and propylene based on monoethylene glycol 15.0-50.0; VAT residue 5.0-40.0; solvent (methanol) to 100.0. (see 3. Patent of the Russian Federation No. 2197513, BI No. 3, 01/27/2003.).

The objective of the invention is to increase the effectiveness of the composition for dehydration and desalting of oil and expanding the range of effective surfactants for dehydration and desalting of oil, as well as improving the rheological properties of the transported products.

The problem is solved by a composition for dehydration, desalting and improving the rheological properties of oil containing a nonionic demulsifier such as a block copolymer of ethylene and propylene oxides based on monoethylene glycol with an average molecular weight of 4300 and a solvent. Moreover, it additionally contains the distillation of the production of diethylene glycol methyl ether, including (wt.%) Ethylene glycol methyl ether 20.0-40.0, diethylene glycol methyl ether 40.0-60.0, methanol 2.0-5.0, water 15, 0-18.0 in the following ratio of components, wt.%:

Block copolymer of ethylene and propylene oxides 15.0-55.0 Distillation 5.0-75.0 Solvent to 100.0

Characteristics of the substances used:

The block copolymer of ethylene oxide and propylene, for example, based on glycols — Reapon-4B: N (C ₂ H ₄ O) _n (C ₃ H ₆ O) _n OAO (C ₃ H ₆ O) _m (C ₂ H ₄ O) _n H, where A = —C ₂ H ₄ —or —C ₃ H ₆ -, n = 14-16, m = 24-27 with a molecular weight of 4300; mass fraction of the main substance 55 ± 5%; kinematic viscosity at 0 ° C 40 mm ² / s; temperature limits for clarification of a solution of a concentration of 100 g in an aqueous NaCl solution of 50-60 ° C; pour point no higher than minus 50 ° C (see 1. TU 6-55-54-91).

The distillation of the production of diethylene glycol methyl ether (see 4. TU 6-14-09-02-82), including, wt.%: Ethylene glycol methyl ether 20.0-40.0, diethylene glycol methyl ether 40.0-60.0, methanol 2.0-5.0, water 15.0-18.0. The refractive index n ²⁰ = 1.4; density ρ = 0.950-1.000; kinematic viscosity ν ₂₀ = 6-10 mm ² / s.

The composition is prepared by simple mixing of the components.

An example of a specific preparation of 1 g of the composition: 0.25 g of distillate are added to 0.40 g of a block copolymer of ethylene and propylene oxides and 0.35 g of solvent is added.

A 1% aqueous solution is prepared from the resulting composition and its demulsifying effectiveness is determined.

The determination of the demulsifying effectiveness of the composition was carried out on artificial emulsions of sulfur oils of the Chekanskoye field with a water cut of 30 wt.%. (see table 1).

The test composition is dosed in the emulsion, the mixture is shaken on a laboratory shaker for 10 minutes at a temperature of 55-60 ° C. Then thermostat for 2 hours at 60 ° C and measure the amount of released water from oil in dynamics.

The determination of the residual water content in oil is carried out in accordance with GOST 14870-77 by the Dean-Stark method.

Sulfur oil of the Chekansky field contains a significant amount of resins and asphaltenes, which are viscous, highly condensed polar substances that can form associates in oil. The mechanical impurities contained in the oil and high-melting paraffins form a crystalline structure upon lowering temperature, on which asphaltenes and resins are adsorbed. This explains the extreme difficulty of the destruction of such water-oil emulsions by known demulsifiers. For effective operation, the new composite demulsifier must have a significant wetting effect. Evaluation of the wetting ability of the claimed composition is carried out by measuring the wetting angle according to the projection of the droplet on the surface of asphalt-resinous compounds and paraffins (see table 2). The wetting angle is measured at 20 ° C in dynamics after the formation of the droplet 1 minute after applying the droplet to the substrate. The reagents are used in the form of 1% aqueous solutions and are applied to the test surface with a microvolume of 7 μl. From the results of the experiments, it is seen that aqueous solutions of the inventive composite composition better wet the surface of asphalt-resinous compounds and paraffins (i.e., have a lower contact angle) compared to the demulsifier Reapon-4B.

Rheological studies are carried out on a rotational viscometer "Reotest-2" with a coaxial measuring device. The dependence of the change in dynamic viscosity (μ, MPa · s) of the oil-water emulsion when adding the inventive composition on the shear rate (D _r , s ^-1 ) at various temperatures (t, ° C) is determined (drawing).

Analysis of the results shows that the use of the inventive composition allows for effective dehydration and desalination of oil, and also improves the rheological properties of oil products.

Table 1
The demulsifying effectiveness of the compositions (dosage 100 g / t) when demulsifying a water-oil emulsion of sulfur dioxide in the Chekanskoye field (water cut 30%) at t = 60 ° C Reagent The amount of released water, ml during sludge time, min The residual water content in oil,% wt. The residual salt content in oil, mg / l 10 twenty thirty 60 90 120 Reapon-4V 42.5 49.4 51.6 54.8 55.5 55.8 1.8 twenty prototype 13:75:12 62.5 67.4 69.0 70.9 72,2 73.5 6.1 46 26:50:24 75.6 81.5 83.1 86.0 87.9 89.8 2.9 twenty 40:25:35 80.1 87.3 89.5 91.1 92.1 92.8 1,2 eighteen claimed composition 13:75:12 64.5 69,4 70.0 71.0 73,2 74.8 4.9 26 26:50:24 77.4 83,2 85.8 88.7 89.7 90.3 1,5 eighteen 40:25:35 80.6 88.4 90.6 91.9 92.3 92.9 1,2 19 table 2
The experimental measurement data of the contact angle with aqueous solutions of the claimed composition Reagent Wetting angle, deg, depending on the time of the start of the experiment, min 1 2 3 4 5 on the surface of asphalt-resin compounds Reapon-4V 49 43 39 31 25 claimed composition 13:75:12 37 29th twenty thirteen 5 26:50:24 35 27 19 eleven 4 40:25:35 31 24 17 8 1 on the surface of paraffins Reapon-4V 58 55 52 47 44 claimed composition 13:75:12 41 33 23 12 2 26:50:24 35 28 21 fifteen 7 40:25:35 38 29th 22 17 10

Claims (1)

Composition for dehydration, desalting and improving the rheological properties of oil, containing a nonionic demulsifier - a block copolymer of ethylene and propylene oxides based on monoethylene glycol with an average molecular weight of 4300 and a solvent, characterized in that it further comprises distillation of the production of diethylene glycol methyl ester, including wt.%: Methyl ethylene glycol ether 20.0-40.0, diethylene glycol methyl ether 40.0-60.0, methanol 2.0-5.0, water 15.0-18.0 in the following ratio of components, wt.%: Ethylene oxide block copolymer and propylene 15.0-55.0 Distillation 5.0-75.0 Solvent (methanol) Up to 100.0