RU2152976C1 - Composition for dehydration and desalting of crude oil and for inhibition of asphaltene-tar-paraffin deposits - Google Patents

Abstract

FIELD: crude oil treatment. SUBSTANCE: composition contains, %: nonionic demulsifier, namely, glycerol-based ethylene oxide/propylene oxide block copolymer with 1-30 ethylene oxide units, 20-80; propylene oxide units, 50-80; and molecular weight 3000-6000; 2-5% nonionic surfactant, 2-5; oxyalkylated polyether resin; and solvent, the balance. Composition shows high efficiency in dehydration of emulsion to 0.20-0.26% residual water with consumption 25 to 50 g/t of anhydrous oil providing also its desalting and inhibition of asphaltene-tar-paraffin deposits. EFFECT: improved working characteristics. 2 tbl, 16 ex

Description

 The invention relates to the field of oil preparation and can be used for dehydration and desalination of oil and protection of oilfield equipment from asphaltene-resin-paraffin deposits (AFS).

 A known composition for dehydration and desalting of oil based on two block copolymers - ethoxylated and oxypropylated propylene glycol or ethylene glycol and ethoxylated or oxypropylated alcohol Reapon 4B (TU 6-55-54-91). However, this demulsifier is not effective enough, does not have a protective effect against (paraffin).

Known composition for dehydration and desalting of oil, including non-inogenic demulsifier based on block copolymers of ethoxylated and oxypropylated propylene or ethylene glycol, a demulsifier based on ethoxylated and oxypropylated ethylene diamine, oil-soluble non-inorganic surface-active substance C _{2 or 4} -mono-ethylene ether diethylene glycol and Nefras (RF patent N 2019555 MKI C 10 G 33/04, publ. 1994). The composition is not effective enough and does not allow to solve the problem of wastewater treatment in oil preparation processes.

 Closest to the proposed invention is a composition for dehydration and desalting of oil, including a nonionic demulsifier based on an oxyalkylated block copolymer and a nonionic surfactant - hydroxyalkylated polyester resins with a molecular weight of 4000-6000, aromatic solvent Nefras Ar 120/200 and additionally non-aromatic solvent, for example methanol (RF patent N 2107711, MKI C 10 G 33/04, publ. 1998). The known composition does not have the properties of protection against paraffin oilfield equipment and does not solve the problem of wastewater treatment in oil preparation processes.

 The basis of the present invention is the creation of a composition for dehydration and desalting of oil inhibiting paraffin, which is highly effective and solves the problems of protecting oilfield equipment from paraffin and the treatment of wastewater in the process of oil preparation.

The problem is solved in that the composition for dehydration and desalting of oil and inhibition of paraffin wax including a nonionic demulsifier based on an oxyalkylated block copolymer, a nonionic surfactant and a solvent, contains a block copolymer of ethylene oxides 1-30 and propylene oxide 50-80 s as a nonionic demulsifier molecular weight of 3000-6000, and as a nonionic surfactant - hydroxyalkylated polyester resin L 5001 M in the following ratio of components, wt.%:
Glycerol-based block copolymer of ethylene and propylene oxides - 20-80
Oxyalkylated Polyester Resin - 2-5
Solvent - Else.

 Block copolymers of ethylene and propylene oxides based on glycerol with the number of units of ethylene oxide 1-30 and propylene oxide 50-80 and with a molecular weight of 3000-6000 are obtained in a known manner (US patent N 3699051, MKI B 01 D 17/04, 1982, N. Schönfeld "Surfactants based on ethylene oxide", M., Chemistry, 1982, 752 pp.). Physico-chemical characteristics of block copolymers used to prepare the demulsifier are presented in table 1.

 The following are used as the oxyalkylated polyester resin: L 4999 M - non-ionic chemical base containing a surfactant (Nalko / Exxon Passport), L 5001 M - non-ionic chemical base containing a surfactant (Nalko / Exxon Passport).

 As a solvent, for example, a mixture of aromatic hydrocarbons can be used - butylbenzene fraction (BBP) according to TU 38-10297-78 or Nefras Ar 120/200 according to TU 38.101809-90, or isopropanol according to GOST 9805-84, or methanol according to GOST 22.22 , or mixtures thereof with water and products such as: ethylene glycol monoethyl ether (MEEG) according to TU 6-09-3222-79, or diethylene glycol monoethyl ether (MEEDET) according to TU 6-01-579783-6-89, or ethylene glycol monobutyl ether (MBEET) according to TU 6-01-646-81, or diethylene glycol monobutyl ether (MBEDET) according to TU 6-01-5757583-6-89.

 The proposed composition is obtained by mixing the components in any sequence and with partial use of a solvent when mixing the components.

 An analysis of the known solutions selected in the search process showed that in science and technology there is no object similar in terms of the claimed combination of features and advantages, which allows us to conclude that the invention meets the criteria of "novelty" and "inventive step".

 To prove the compliance of the proposed solution with the criterion of "industrial applicability" we give a specific example of the preparation of the composition and various compositions with different contents of the components.

 Example 1

 To 35 g of a block copolymer with a molecular weight of 6000 add 5 g of surfactant L 5001 M and 60 g of solvent, a butyl-benzene fraction. The mixture is thoroughly mixed until smooth.

 Examples 2-15 are performed analogously to example 1.

 Example 16 (prototype).

The resulting compositions are homogeneous mobile liquids from yellow to brown in color with a density d of 0.900-0.998 g / cm ³ , viscosity η not higher than 60 mm ² / s, t solidification, not higher than -50 ^o C and are presented in table 1.

Tests of the composition are carried out in oils, the physico-chemical properties of which are as follows:
density at 20 ^o C, kg / m, 0.950-0.985
viscosity, MPa s, at 5 ^o C 3000-3500 at 20 ^o C 910-1000.

Content:
sulfides Fe (mg / l) - 350-400,
resins - 20-50%, sulfur (total) -15%, paraffins -15-30%,
asphaltenes - 10-15%.

The test demulsifier is dosed into the water-in-oil emulsion and shaken on a Wagner laboratory shaker for 30 minutes at room temperature. Then thermostat at 40 ^o C for 2 hours and measure the amount of freely released water. In the process of treating a water-oil emulsion with a demulsifier, a deep desalination occurs together with the released water, as a result of which the salt content decreases from 1-5 g / l to 10-18 mg / l. The determination of the residual water content in oil is carried out in accordance with GOST 14870-77 by the Dean-Stark method.

Evaluation of the effectiveness of the samples to prevent paraffin is carried out according to the following indicators:
- for washing the film of oil with this sample;
- the value of the dispersion of paraffin in the sample medium;
- for washing AFS.

 Determination of washing film of oil is carried out in the following order. Oil is poured into a glass tube to a certain mark, spent by the reagent at the rate of 0.005% on an active basis and left to stand for 20 minutes. Then the oil is poured, and the formation water is poured to half the tube, the oil is added to the mark, the tube is closed with a ground stopper. Then, at the same time as the stopwatch is turned off, the tube is turned over. Oil and water vary in volume. The area of the washing surface of the test tube occupied by formation water instead of oil is fixed. The result is considered to be excellent if washing of 70% of the area occurs in 30 seconds, good in 60 seconds and satisfactory in 180 seconds.

Dispersion of paraffin and surface washing. These two methods are combined in one laboratory procedure and are carried out in a conical flask, in which 50 ml of produced water is placed, the test reagent is dosed. Paraffin deposits weighing 0.5 g are placed in the same flask. The contents of the flask are heated until the paraffin is melted (60 + 90 ^o C), and then cooled by stirring. After cooling to 20 + 25 ^o C measure the particle size of the dispersion of paraffin σ and the area of the working surface of the flask, not covered (smeared) with paraffin deposits (S).

 According to the methodology, the result is considered to be excellent with a dispersion value of 0.1-1.0 mm, good with a dispersion value of 1.0-2.0 mm, satisfactory with a dispersion value of 2.0-5.0 mm, unsatisfactory with a dispersion value> 5 mm .

 When assessing the washing of ARPD from the surface, the result is considered to be excellent if the fraction of washing from the ARPD of surface S,% is 90-100, good is 80-90, satisfactory is 50-80 and poorly <50.

 The degree of wastewater treatment is determined by the method described in OST 39-133-81 "Water for waterflooding of oil reservoirs. Determination of oil content in field wastewater" and evaluated by the oil content in wastewater. The test results of the demulsifying effectiveness of the proposed demulsifier and prototype are presented in the table. An analysis of the data presented in the tables shows that the proposed demulsifier has a protective effect against paraffin and allows to solve the problem of wastewater treatment in oil preparation processes.

Claims (1)

Composition for dehydration and desalting of oil and inhibition of asphaltene-resin-paraffin deposits, containing a nonionic demulsifier based on an oxyalkylated block copolymer, a nonionic surfactant and a solvent, characterized in that it contains a non-ionic demulsifier based on an oxyalkylated block copolymer of ethylene oxide and ethylene block copolymer of it glycerol with the number of units of ethylene oxide 1 - 30 and propylene oxide 50 - 80 and with a molecular weight of 3000 - 6000, and as a nonionic one surfactant is an oxyalkylated polyester resin - L 5001 M, in the following ratio of components, wt.%:
Glycerol-based block copolymer of ethylene and propylene oxides - 20 - 80
Oxyalkylated Polyester Resin - 2-5
Solvent - Other

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