RU2129585C1 - Composition for crude oil dehydration and desalting, inhibition of corrosion and asphaltene-tar-paraffin deposits - Google Patents

Abstract

FIELD: oil and gas production. SUBSTANCE: demulsifier-corrosion inhibitor is composed of, wt %: dimethyl phosphite, 0.2-1.5; nitrogen-containing compound, 0.2- 16.5; oxyethylenated alkylphenol, 15.0-25.0; phosphenox-H-12, 10.0-25.0; organic solvent, the balance. Solvent is selected from the group including: ethanol, industrial-grade methanol, petroleum-origin toluene, xylene, butylbenzene, and their mixture and water. EFFECT: increased demulsification efficiency. 2 cl, 2 tbl, 14 ex

Description

 The invention relates to means for breaking oil-water emulsions while protecting oil collection, transport and treatment systems from corrosion and asphaltene-tar-paraffin deposits and can be used for oil dehydration during pipe demulsification at oil recovery facilities, industrial oil treatment plants, oil refineries and deep dehydration and desalination processes oil, as well as an independent corrosion inhibitor in carbon dioxide, hydrogen sulfide and mixed media and as a ibitor asfaltenosmoloparafinovyh deposits in oilfield equipment.

 A known composition for dehydration and desalination of oil based on nonionic surface-active alkyl phenols (Levchenko D.N. et al. "Emulsion of oil with water and methods for their destruction" M., Chemistry, 1987, p. 110).

 However, this demulsifier is ineffective in the preparation of sulphurous oil, since the process proceeds with excessive consumption rates, at a relatively high temperature and a long settling time.

A known composition for dehydration and desalting of oil, including: nonionic demulsifier type block copolymer of alkylene oxides - 0.7-1.5; bottoms from the production of butanol by the oxosynthesis, containing C ₁ - C ₄ aliphatic alcohols and their esters - 0.2-0.8; butylbenzene fraction - 0.2-0.8, all in parts by weight (A.S. USSR N 1172937 C 10 G 33/04, 1985).

 The disadvantage of the composition is the low demulsifying effectiveness.

 Known composition for desalting and dehydration of oil, inhibiting corrosion and asphaltene-resin-paraffin deposits, including dimethyl - or diethylphosphoric acid, nonionic demulsifier, amine and solvent (RF patent N 2050402, C 10 G 33/03, 1995).

 Its disadvantage is the lack of effectiveness when used for high viscosity and sour crude oils.

 The closest in technical essence and the achieved effect to the declared one is a composition for dehydration and desalting of oil, corrosion inhibition of oilfield equipment and asphaltene-tar-paraffin deposits, including dimethylphosphite, amine or triethanolamine, ethoxylated alkylphenol phosphenox H-6, diproxamine 15 or 15proxamine 157 or 15 RF patent N 2090590, MKL C 10 G 33/06, 1995).

 However, the known composition is not effective enough when used for high viscosity and sour crude oils.

 The present invention is based on the task of creating a complex action composition — an oil demulsifier, a corrosion inhibitor in carbon, hydrogen sulfide-containing and mixed media and asphaltene-tar-paraffin deposits, which makes it possible to effectively separate oil-water emulsions, inhibit corrosion of oilfield equipment and asphaltene-tar-paraffin deposits.

The claimed composition for dehydration and desalting of oil, corrosion inhibition, asphaltene-resin-paraffin and scaling, including dimethyl phosphite, nitrogen-containing compounds, ethoxylated alkyl phenols based on trimers propylene, a corrosion inhibitor based on the product of the interaction of phosphorus oxychloride and neonol-based ethyleneamine-based demylene polymer - diproxamine-157-65M or diproxamine-157 and a solvent, as a corrosion inhibitor based on the product of the interaction of chlorine isi phosphorus and neonol, the composition contains phosphenox-H-12 in the following ratio of components, wt.%:
Dimethylphosphite - 0.2-1.5
Nitrogen-containing compound - 0.2-1.5
Oxyethylated alkyl phenol - 15.0-25.0
Fosphenox-N-12 - 10.0-35.0
Diproxamine-157 or diproxamine-157-65M - 10.0-25.0
Solvent - Other
In an advantageous embodiment, the composition contains, as a solvent, an organic solvent selected from the group consisting of alcohols, industrial methanol, petroleum toluene, xylene, butylbenzene, or a mixture thereof and water, in the following ratio of components, wt. %:
Dimethylphosphite - 0.2-1.5
Nitrogen-containing compound - 0.2-1.5
Oxyethylated alkyl phenol - 15.0-25.0
Fosphenox-N-12 - 10.0-35.0
Diproxamine-157 or diproxamine-157-65M - 10.0-25.0
Water - 0.1-1.0
Solvent - Other
Dimethyl phosphite is used according to TU-6-36-5763445-6-88.

As the nitrogen-containing compound, for example, triethanolamine or monoethanolamine, or diethylamine, or diethanolamine according to TU-6-02-916-79, or NH ₄ OH are used.

As ethoxylated alkyl phenols, for example, alkyl phenols can be used:
AF ₉ -6, AF ₉ -12 according to TU 38.507-63171-91.

Fosfenoks H-12 was prepared by a conventional interaction with phosphorus oxychloride Neonol AF ₉ -12 ( "The Chemistry of Organophosphorus Compounds" by E. E. Nifant'ev, MSU, 1971, p. 148) and used according to specifications 6-40-5763445-23-90, as a corrosion inhibitor.

 Diproxamine-157 is a block copolymer of ethylene and propylene oxides based on ethylene diamine with a molecular weight of about 5000, which is the active base of the commercial form of diproxamine 157-65M, which is used according to TU-14-61476 as a demulsifier.

 As a solvent, for example, industrial methanol, petroleum toluene, xylene (ortho, steam, meta), as well as ethylbenzene, butylbenzene, or a mixture thereof, and water can be used.

 A new set of claimed essential features will make it possible to obtain a new technical result, namely, to obtain an effective composition of complex action.

 An analysis of the known solutions selected during the search showed that there is no object in science that is similar to the claimed combination of features and has high demulsifying properties, properties to inhibit corrosion of oilfield equipment and deposits of asphalt-resin-paraffin deposits, which allows us to conclude that the invention meets the criteria of "novelty" and "inventive step "

 To prove the conformity of the claimed object with the "industrial applicability", we give specific examples of the preparation of compositions 1-14 (see table. 1).

The compositions are prepared by sequential mixing of dimethyl phosphite with neonol AF ₉ -12 in a reactor equipped with a stirrer with a speed of 60 rpm at 100 ^o C for 30 minutes. The resulting mixture was cooled to 20 ^° C. and triethanolamine was added thereto with stirring at 20 ^° C. for 10 minutes, then, with stirring, we introduced phosphenox H-6 for 10 minutes, then diproxamine 157-65M was added with stirring for 10 minutes. The resulting mixture was dissolved in a mixture of solvents, including methanol, toluene, p, m, o - xylene, water, with stirring for 40 minutes.

 Compositions N 1-14 are prepared similarly to the above, changing the starting components and their amount according to table 1.

 The obtained compositions are tested for demulsifying activity, for the effectiveness of inhibiting corrosion in hydrogen sulfide oxygen-containing, carbon dioxide and mixed media and asphaltene-tar-paraffin deposits, as well as for the effect of aftereffect and transport properties.

 Tests of the demulsifying activity of the compounds is carried out on an artificial emulsion of 60% and 40% water cut. Oil-water emulsions are prepared by mixing crude oil and water models (produced water) using a mixer at a speed of 3000 rpm for a certain time immediately before the demulsifier test. To assess the effectiveness, Siberian oil (Strizhevoy field) with fresh water (30 g / l) and Kuibyshev oil and mineralized water (170 g / l) are used according to the Bashnipineft Method for Determining the Demulsifying Ability of Demulsifying Reagents.

Freshly prepared water-oil emulsion is poured into measuring tubes with a capacity of 20 cm ³ to 10 cm ³ . In samples of the emulsion, 1% solutions of the investigated compositions and the composition of the prototype are dosed using a microsyringe.

The samples are mixed and placed on the sludge in a water bath at a temperature of 20 - 30 ^o C for 1 hour.

 The kinetics of water separation during sedimentation is expressed as the amount of water released in% of the water content in the initial sample of the emulsion. The amount of water released is monitored every 15 minutes.

 The test results are shown in table 2.

Tests of samples as inhibitors of hydrogen sulfide carbon dioxide corrosion are carried out according to OST-39-099-79 "Corrosion inhibitors. Method for assessing the effectiveness of the protective effect of corrosion inhibitors in oilfield wastewater", in a standard solution with a density of 1.12 g / cm ³ . Plates from St 3 are used as samples. The exposure time of the samples when evaluating the inhibitory effect of the composition is 6 hours. The concentration of the reagent in all cases is 50 mg / L. With hydrogen sulfide corrosion, the concentration of hydrogen sulfide is 10 mg / L. The test results are presented in table 3 and are the arithmetic average of four measurements with an estimate of standard deviation, as provided by OCT.

 The composition is tested for the inhibitory effect in an oxygen-containing medium according to GOST 9.506-87. The method consists in determining the mass loss of metal samples during their stay in uninhibited and tested environments.

The test medium is a standard solution of wastewater simulating oilfield formation water with an accuracy of 1.12 g / cm ³ . To prepare a model of produced water, magnesium chloride 22 g, calcium chloride 23 g, calcium sulfate 1.4 g, sodium chloride 144 g are used. To prepare an oxygen-containing solution, these salts are dissolved in 1 liter of distilled water.

 Before the experiment, metal samples are degreased and weighed to the nearest 0.00005 g.

 For corrosion tests, two installations with I-shaped glass vessels are used simultaneously, in which a linear fluid flow is created. Samples are placed in the knee of a two-necked I-shaped vessel filled with a standard oxygen-containing solution. In the second installation, the samples are immersed in an oxygen-containing solution with the addition of a test inhibitor.

 The test duration is 6 hours.

 The difference in the weight of the sample with and without corroded plaque determines the effectiveness of the inhibitor.

 The results are presented in table 2.

Determination of the protective effect in mixed media:
The protective effect of the reagents was determined by the method of polarization resistance, which is widely used in laboratory practice. The method includes the following sequential operations:
- preparation of a reservoir water model of the Samotlor field;
- preparation of electrodes, in which samples were used St 20 VTZ;
- determination and stabilization of the reference corrosion rate in the presence of precipitation - corrosion products, the formation of which occurs on the electrodes in advance;
- preparation of a reagent solution of the required concentration;
- input of the reagent solution into the cell;
- fixing the polarization resistance or directly the corrosion rate after entering the reagent, achieving stabilization of its values;
- visual inspection of the electrodes.

A feature of this technique is the preliminary formation of a small layer of corrosion products on the surface of the electrodes, presumably of the composition FeO - FeCO ₃ , which makes it possible to bring the experimental conditions closer to those existing in the field.

Determination of aftereffect
The effect of the aftereffect of the reagents was determined in the following order:
after reaching the control corrosion rate, the electrode was placed for 3 min in a sample of undiluted (pure) reagent, then again in the cell. Further, a change in the values of the corrosion rate over two days was recorded. On the second day, the electrolyte was completely replaced.

Definition of transport properties
The transport properties of the known and claimed reagent are determined by introducing the entire portion of the reagent into the oil layer, which is located in the upper part of the cell. Before entering the reagent determine the control rate of corrosion. Next, the changes in the values of the corrosion rate over time are recorded.

In the process of conducting experiments to determine the protective effect, aftereffect and transport properties, the supply of gases (CO ₂ and N ₂ ) was carried out continuously.

 Each experiment at positions 1.2, 1.3, 1.4 was duplicated, and a third control experiment was carried out in the discrepancy between the results. The duration of one experiment was 7 hours; all reagent solutions were prepared in isopropyl alcohol.

 The experimental results are shown in table 3.

 As noted above, all experiments were carried out with the preliminary formation of corrosion products on the electrodes, which brings laboratory conditions closer to the existing field ones, since in real conditions the pipe surface is always covered with a layer of scale and corrosion products. In this regard, of the two indicators characterizing the effectiveness of the inhibitor (protective effect and residual corrosion rate - OSK), OSK is more informative.

 Analysis of the data in table 3 shows that although both reagents are effective at low specific dosages (10-15 mg / l), a lower OSK value is achieved using the claimed composition (0.13-0.14 mm / year).

 Both investigated products are capable of redistribution from the oil to the aqueous phase, which is important when using them to protect pipelines with a variable flow structure. This ability is most strongly expressed in the claimed composition.

 An analysis of data on the aftereffect shows that this property is weakly expressed in both reagents, so the main option for the technology will be constant dosing.

 The test composition No. 1-5 on the effect of inhibiting asphaltene-tar-paraffin deposits is carried out according to the laboratory method for determining the dispersion of particles, which consists in the following.

 100 ml of produced water is poured into a 200 ml conical flask and 1 ml of the test reagent is dosed. The walls of the flask are treated with the obtained 1% solution of the reagent in produced water. 2-3 g of paraffin deposits of the same field are added and heated in a water bath until they are completely melted. Then the flask is sharply cooled under a stream of cold water, shaking it in a circular motion. According to the state of paraffin deposits, the dispersing ability of the reagent is evaluated. The test results are presented in table 2.

 From the data presented in tables 1, 2, 3, it can be seen that the claimed composition has high demulsifying and inhibiting corrosion and paraffin deposits at low concentrations (10-15 mg / l), and also has the property of an independent transition from the oil to the aqueous phase, which opens the possibility of their use for the protection of partially flooded extended pressure oil pipelines, as well as pipelines of the oil recovery system with a variable flow structure according to the technology of constant dosing. The threshold concentrations of reagents at which they are effective as corrosion inhibitors and demulsifiers are close to each other. This opens up prospects for the protection of pipelines and demulsification of oil with one reagent.

Claims (1)

1. Composition for dehydration and desalting of oil, inhibiting corrosion and asphaltene-tar-paraffin deposits, including dimethylphosphite, a nitrogen-containing compound, hydroxyalkylated alkyl phenols based on propylene trimers, a corrosion inhibitor based on the reaction product of phosphorus oxychloride and neonol, ethylene-ethylene diamine-based ethylene diamine-based ethylene oxide block copolymer - diproxamine-157 or diproxamine 157-65M, and a solvent, characterized in that the composition as a corrosion inhibitor contains fosphenox-N-12 pr and the following ratio of components, wt.%:
Dimethylphosphite - 0.2 - 1.5
Nitrogen-containing compound - 0.2 - 1.5
Oxyethylated alkyl phenol - 15.0 - 25.0
Fosphenox-N-12 - 10.0 - 35.0
Diproxamine-157 or diproxamine 157-65M - 10.0 - 25.0
Solvent - Other
2. The composition according to claim 1, characterized in that it contains an organic solvent selected from the group consisting of alcohols, industrial methanol, petroleum toluene, xylene, butylbenzene or a mixture thereof and water in the following ratio, wt.%:
Dimethylphosphite - 0.2 - 1.5
Nitrogen-containing compound - 0.2 - 1.5
Oxyethylated alkyl phenol - 15.0 - 25.0
Fosphenox-N-12 - 10.0 - 35.0
Diproxamine-157 or diproxamine-157-65M - 10.0 - 25.0
Water - 0.1 - 1.0
Organic Solvent - Else

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