RU2324005C2 - Composition for equipment protection from corrosion and inorganic salt deposits - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: composition components, wt.%: sodium polyacrylate - 0.3; corrosion inhibitor SNPH-6035 - 0.2; water - remainder.

EFFECT: improved corrosion protection properties of equipment protection composition due to preparation of mixture of salt deposition inhibitor and corrosion inhibitor with synergistic effect.

3 tbl

Description

The invention relates to the oil and gas industry and can be used to combat deposits of insoluble inorganic salts and corrosion. At present, various inhibitors, as a rule, of single-function action, are used both to prevent salt deposits and to protect against corrosion. The specifics of anticorrosion protection in the oil and gas industry is that measures to combat corrosion often need to be taken when the field is already equipped and the main equipment and communications are in operation. The use of other very effective protective measures (for example, coatings) requires, as a rule, the replacement of existing equipment with new equipment, which is associated with high capital costs. Therefore, the use of inhibitory protection is predominant [Gonik A.A. Corrosion of oilfield equipment and measures to prevent it. M .: Nedra, 1976, p.192]. So, the corrosion inhibitor SNPCH-6035 produced by NIIneftepromkhim (TU 2458-267-05765670-2000), Kazan, is known.

Each of the inhibitors acts in its intended area. The corrosion inhibitor does not protect against the formation of salts, and the scale inhibitor does not protect against corrosion, but only does not cause it.

Closest to the claimed invention for the same purpose is a composition containing, wt.%: Polyaminomethylphosphonic acid 0.1-0.125, sodium salt of polyacrylic acid 0.375-0.9, the rest is water [RU No. 2230766, MKI C09K 3/00, E21B 37/06].

The action of the composition is aimed at preventing salt deposits and is completely ineffective against corrosion.

An object of the invention is to increase the anticorrosive effect of the composition for protecting equipment by creating a mixture of a scale inhibitor and a corrosion inhibitor with a synergistic effect.

To solve the problem, a composition designed to prevent the formation of scaling on equipment in wells, containing a scaling inhibitor, further comprises a corrosion inhibitor SNPCH-6035, in the following ratio, wt.%:

Polyacrylic Acid Sodium Salt 0.3 Corrosion Inhibitor (SNPCH-6035) 0.2 Water Rest

The composition of the ingredients forms a homogeneous composition, the effectiveness of which in preventing the formation of salts in oilfield equipment is comparable to that of the scale inhibitor D54, and the corrosion effect is increased. The study of the protective effect of scaling of the compositions was carried out in laboratory conditions according to the known method described in RD 39-0148070-026 VNII-86.

The protective anticorrosion effect was calculated by the method of polarization resistance using the Monicor-1M device.

The study used a 0.5% solution of inhibitors and mixtures of inhibitors. Solutions were prepared immediately prior to testing.

The results of laboratory tests showed that the most active component is the sodium salt of polyacrylic acid - Narlex D54 (hereinafter D54). The results of determining the optimal composition of the mixture showed that the mixture is most active, where the content of components D54: SNPCH-6035 = 0.1: 0.4 wt.% (Table 1).

The synergism was quantified by comparison with the additivity curve. According to the additivity rule, the effectiveness of a mixture of components (Esm) is equal to the sum of the efficiencies of the components that make up this mixture. The additivity efficiency of the mixture is calculated. We denote the efficiency obtained in this way as the efficiency of additivity (EA). For a quantitative assessment, we use the ratio Esm / EA. If Esm / Ea> 1, then a synergistic effect is manifested, and if Ep / Ea <1, then the effect is antagonistic (table 2).

According to the results presented in table 2, it is seen that the composition of the mixture D54: SNPCH-6035 0.1: 0.4 wt.% At concentrations of 20-50 mg / dm ³ and the composition of the mixture D54: SNPCH-6035 0 have the greatest synergy effect , 3: 0.2 wt.% At a concentration of 5-20 mg / DM ³ .

Studies have shown that the optimal ratio of components in the mixture is D54: SNPCH-6035 0.3: 0.2 wt.%, And the working range of concentrations is up to 20 mg / dm ³ .

Table 3 shows the results of corrosion tests.

One of the criteria when choosing an inhibitor and its dosage is to provide the necessary level of inhibition efficiency. Table 2 allows you to choose the composition of the mixture and the specific consumption at which the mixture shows the greatest efficiency, and also allows you to quantify the effect of synergism. Table 3 makes it possible to evaluate the protective corrosion effect of the selected mixture composition.

These advantages allow you to:

use a more efficient way to periodically pump the inventive composition into the annulus of producing wells;

prevent the deposition of salts in the production column;

inhibit the corrosion process in the production column;

economically and rationally use a solution of the composition with determining its optimal content in the produced water;

the components that make up the composition do not affect the quality of the oil preparation;

this composition can be used to protect from scaling and corrosion not only wells, but also water pipes of the reservoir pressure maintenance system.

Table 1
The results of the effectiveness of the inhibition of pure inhibitors as scale inhibitors and their compositions Component composition, wt.% The total concentration of the mixture, mg / l twenty thirty fifty Narlex-D54: H ₂ O 0.5: 99.5 62 79 85 SNPCH-6035: H ₂ O 0.5: 99.5 one 0.5 one D-54: SNPCH-6035: H ₂ O 0.1: 0.4: 99.5 53 60 76 D-54: SNPCH-6035: H ₂ O 0.2: 0.3: 99.5 57 64 71 D-54: SNPCH-6035: H ₂ O 0.3: 0.2: 99.5 70 72 76 D-54: SNPCH-6035: H ₂ O 0.4: 0.1: 99.5 75 70 80

table 2
The ratio of Esm / EA for a mixture of inhibitors at different concentrations The concentration of the mixture, mg / DM ³ The content in the mixture of Narlex D54, wt.% 0 0.1 0.2 0.3 0.4 0.5 5 0 0.23 1,11 1.26 0.81 1.00 10 0 0.92 0.94 1.18 0.95 1.00 twenty 0 1.29 1,08 1.13 1.10 1.00 thirty 0 1.23 1,03 1,03 0.93 1.00 fifty 0 1.33 1.33 0.96 0.97 1.00

Table 3
Protective corrosion effect of inhibitors as corrosion inhibitors Inhibitor Protective corrosion effect,% at specific dosage, mg / l thirty fifty Narlex-D54: H ₂ O 0.5: 99.5 12 13 SNPCH-6035: H ₂ O 0.5: 99.5 36 39 D-54: SNPCH-6035: H ₂ O 0.1: 0.4: 99.5 5 36 D-54: SNPCH-6035: H ₂ O 0.3: 0.2: 99.5 51 62

Claims (1)

Composition for protecting equipment from corrosion and inorganic scaling, including the sodium salt of polyacrylic acid and water, characterized in that it additionally contains a corrosion inhibitor SNPCH-6035 in the following ratio, wt.%: polyacrylic acid sodium salt 0.3 corrosion inhibitor SNPCH-6035 0.2 water rest