RU2531298C1 - Method for preventing deposits of non-organic salts - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: compound for preventing deposits of non-organic salts in oil-field equipment, in wt %: agent PAF-13A 1.5-15, which represents aqueous solution of polyethylenepolyaminemethylphosphonate admixed with sodium chloride, acid sodium salts of phosphoric and phosphorous acids and ethyleneglycol - 2-10. It contains additionally in wt %: aqueous solution of the mixture of sodium salts of nitrilotrimethyl-phosphonic acid and hydrochloric acid - production wastes of chelating agent Korilat 75-90, sodium hydrate - 0.35-3.4, nitrilotrimethyl-phosphonic acid (NTF) - 1.5-4.0, thiocarbamide - 0.05-0.2.

EFFECT: compound is an effective inhibitor to prevent deposits of carbonate and sulphate non-organic salts; it has low unit costs, low corrosion activity towards metal equipment, low freezing temperature and prevents saline deposits in conditions of oil production with any degree of water content.

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Description

The invention relates to the field of oil production, in particular to compositions for preventing scaling in wells with different water cut and temperature of the produced fluid, and can be used to combat deposits of insoluble inorganic salts in oilfield equipment in the processes of oil production and preparation. As you know, in Russia when salt is used in at least 11,000 wells equipped with electric centrifugal pumps (ESPs), salts precipitate. At the same time, calcium carbonate precipitates in 85-88% of wells and calcium sulfate in 10-12% (Information Bulletin of Novomet Group of Companies, A. Chebunin, No. 1 (07), June 2009). The formation of salt deposits increases the hydraulic resistance to the passage of fluid and can even lead to complete blockage of the pipeline.

Currently, various scale inhibitors are used to prevent inorganic salt deposits, containing mainly organophosphorus compounds and various acids, which makes the inhibitors aggressive towards the equipment used. Therefore, the creation of effective scale inhibitors with low corrosiveness for wide climatic zones is very important.

Known scaling inhibitor, patent of the Russian Federation No. 21115631, C02F 5/14, publ. 07/20/1989, containing, wt.%:

nitrilotrimethylphosphonic acid, hereinafter NTP 18-22, zinc oxide 3.2-4.9 sodium hydroxide 5.5-6.5 water rest

The disadvantages of this composition are the content of toxic zinc compounds (3.2-4.9%) and the high consumption of expensive NTF (18-22%).

The known composition (RF patent No. 2070910, MKI ⁶ C09K 3/00, 1996) to prevent scaling during oil and gas production from wells, containing, wt.%

NTF 0.2-0.5 hydrochloric acid 8.0-13.0 hydrofluoric acid 1.0-3.0 water rest

The action of the composition is mainly aimed at preventing the deposition of sulfate salts and is ineffective against carbonate salts. In addition, the presence in this composition of hydrochloric and hydrofluoric acids makes the composition corrosive.

A known scale inhibitor, which is an aqueous solution of polyethylene polyaminomethylene phosphonate with impurities of NaCl, acidic sodium salts of phosphoric and phosphorous acids. In industry, the composition is produced at the Novo-Cheboksary Khimprom OJSC under the trade name PAF-13A (grade A and grade B) according to TU 2439-360-05763441-2001 with amendment 1, 2. PAF-13A prevents deposits of mainly carbonate salts .

In the oil industry, PAF-13A grade B is used according to RD 39-0148070-OOZVNIINP, 1086.

The disadvantages of the reagent PAF-13A grade B include low efficiency in preventing the deposition of salts, which in the concentration range up to 60 mg / l does not exceed 50%, PAF-13A grade A - up to 65%. Both grades are highly corrosive to carbon steel.

The closest in technical essence and the claimed composition is a composition for preventing inorganic scaling (RF patent No. 2230766, C09K 3/00, 06/20/2004 Bull. No. 17), containing, wt.%

reagent PAF-13A 0.1-0.125 polyacrylic sodium acids (Narlex-D54) 0.375-0.9 water or an aqueous solution of ethylene glycol rest

The disadvantages of this composition are the low efficiency of not higher than 70% and the high cost of the inhibitor due to the use of Narlex-D54 in imported expensive raw materials.

The objective of the invention is a new effective, less aggressive inhibitory composition for preventing deposits of mineral salts in oil production processes, expanding the arsenal of known scale inhibitors for use in climatic conditions of the northern regions.

The technical result consists in creating the inventive inhibitory composition of scaling, effectively preventing the formation of carbonate and sulfate mineral salts, having a low pour point, low corrosiveness in relation to metal equipment, low specific cost. In the claimed inhibitory composition of scaling use production waste.

The technical result is achieved by the proposed composition, including: an aqueous solution of polyethylene polyaminomethylphosphonate with impurities of NaCl, acidic sodium salts of phosphoric and phosphorous acids - PAF-13A, ethylene glycol and an additional aqueous solution of a mixture of sodium salts of nitrilotrimethylphosphonic and hydrochloric acids - a waste product of the preparation of complexon Corilate , sodium hydroxide, nitrilotrimethylphosphonic acid (NTP), thiocarbamide, in the following ratio of components, wt.%:

reagent PAF-13A 1,5-15 Athos-300M preparation - production waste complexone corilate 75-90 sodium hydroxide 0.35-3.4 nitrilotrimethylphosphonic acid (NTP) 1.5-4.0 thiocarbamide 0.05-0.2 ethylene glycol 2-10

As the reagent PAF-13A, an aqueous solution of polyethylene polyaminomethylphosphonate with impurities of NaCl, acidic sodium salts of phosphoric and phosphorous acids PAF-13A grade A, produced according to TU 2439-360-05763441-2001, amended, is used. 12.

As an Afon-300M preparation, a waste product of Corilate complexone, an aqueous solution of a mixture of sodium salts of nitrilotrimethylphosphonic and hydrochloric acids is used in accordance with TU 2499-540-05763441-2012. As sodium hydroxide, NaOH is used according to GOST 4328-77 amended. 12.

NTF is taken according to TU 2439-347-057634410-2001 or according to TU 2458-007-50643754-2005.

Thiocarbamide is taken according to GOST 6344-73. Thiocarbamide is a colorless crystalline powder soluble in water.

Ethylene glycol is used according to GOST 19710-83.

Distinctive features of the claimed composition is the introduction of an aqueous solution of a mixture of sodium salts of nitrilotrimethylphosphonic and hydrochloric acids - Afon-300M, sodium hydroxide, nitrilotrimethylphosphonic acid - NTF, thiocarbamide, which allows to obtain a composition that is highly effective in preventing the formation of carbonate and sulfate mineral salts, high the coefficient of transition from the oil-water emulsion to its aqueous phase, low corrosiveness in relation to the metal is equipped w, low pour point and low unit cost.

In the patent and scientific and technical literature there are no compositions identical to the claimed, which indicates its novelty.

The inventive step of the proposed composition is determined by the ratio of the components, which allows to obtain a composition that works efficiently with the selected ratios of the initial components of the composition, at low temperature (up to minus 46 ° C) and low corrosion aggressiveness of the composition (0.020-0.035 g / m ² hour), while solving the environmental task of recycling production waste, which reduces the cost of the final commercial product.

To prove the compliance of the claimed composition with the criterion of "industrial applicability" we give examples of specific compositions, see table 1.

The composition is prepared as follows. When the mixer is switched on, the calculated amount of waste from the production of complexon Corilat is loaded into the reactor. Then, sodium hydroxide, ethylene glycol and thiocarbamide are introduced into the reactor sequentially with the stirrer turned on. Stirring is carried out until thiocarbamide is completely dissolved. The next step is the sequential introduction with constant stirring of the calculated amount of NTF and PAF-13A. Stirring is carried out until the complete dissolution of the NTF.

Specific formulations are evaluated as scale inhibitors, determining their protective effect, their pour point and corrosion activity. The calculation of the unit costs of the treatment of produced water in comparison with the prototype.

Testing the effectiveness of the claimed composition as an inhibitor of scaling was carried out in accordance with the "Methodology for determining the effectiveness of the inhibition of precipitation of sulfate and calcium carbonate" developed by NPO Soyuzneftepromkhim on the provisions of RD 39-0148070-026 VNIINP-86. As test environments, we used reservoir water models (MPV) of the fields of RN-Purneftegaz LLC: Tarasovskoye, Barsukovskoye, Komsomolskoye, Novo-Purpeyskoye, Festivalnoye. The ionic composition of the MPV of each of the fields is shown in table 2.

According to the chemical composition of the water of these deposits belong to the waters of calcium chloride and calcium sulfate type. Salt compositions of formation waters simulating carbonate deposits of the Tarasovskoye and Festivalnoye fields are given in Table 3. The composition of formation water, simulating the simultaneous presence of carbonate and sulfate salts, characteristic of the waters of the Barsukovsky, Komsomolsky and Novo-Purpeyskoye fields, is given in Table 4.

The water model prepared in accordance with the calculated values of Tables 3 and 4 corresponded to the ionic composition of the formation water of a particular field. The inhibitor is injected into the water model solution immediately before the experiment. The effectiveness of the composition is determined at concentrations of 10, 20, 30 mg / L. Control and inhibitor cells are thermostated at 80 ° C. Then the samples are cooled to 20 ° C and filtered to remove the precipitate. In filtered water, the residual content of calcium ions is determined. Three parallel determinations of effectiveness are carried out at each dosage, and then the arithmetic average of the obtained results is calculated.

The effectiveness of the scale inhibitor (E _ISO ,%) is determined by the formula:

$$E_{\mathrm{AND}\mathrm{FROM}\mathrm{ABOUT}}=\frac{\mathrm{FROM}R-\mathrm{FROM}x}{\mathrm{FROM}\mathrm{about}-\mathrm{FROM}x}*\mathrm{one}00$$

where C - a content of calcium ions in the sample after incubation containing no scaling inhibitor, mg / dm ^3;

Cp is the content of calcium ions after temperature control in a sample containing a scale inhibitor, mg / DM ³ ;

Co - the content of calcium ions in the initial solution before temperature control, mg / DM ³ .

The results on the effectiveness of the claimed composition as an inhibitor of scaling are shown in table 5.

As can be seen from table 5, the effectiveness of preventing carbonate deposits in the water models of the Tarasovskoye and Festivalnoye fields of Purneftegaz when testing the inventive composition with a concentration of 10-30 mg / l is 90-98%, while for the prototype under comparable conditions, the efficiency is 65-70%.

The effectiveness of preventing a mixture of carbonate and sulfate deposits in the water models of Barsukovsky, Novo-Purpeisk and Komsomol deposits when testing the inventive composition with a concentration of 10-30 mg / l is 83-94%, while for the prototype under comparable conditions, the efficiency is 52-61 %

The pour point and corrosiveness of the claimed compounds are shown in table 6.

The pour point of inhibitory compounds is determined in accordance with GOST 4328-77. The data in table 6 characterize the compositions as reagents suitable for use in winter conditions. The pour point of the compositions is not higher than minus 40 ° C.

Corrosion aggressiveness of the claimed compounds is established by the value of carbon steel corrosion rate. In accordance with GOST R 905-2007, measurements of the corrosion rate were carried out according to the following procedure. Fat-free and weighted plates made of steel grade St3 according to GOST 380 (50 × 20 × 2) mm in size with embossed numbers and a hole for suspension are placed in the cylinder of the device into which 150 cm ^{3 of the} test composition are preliminarily poured. A cylinder with plates is placed in a thermostat or in a water bath with a temperature of (20 ± 2) ° С. After 24 hours, the plates are removed from the solution, washed for a long time under a stream of water, rinsed with alcohol, dried with filter paper, kept in a desiccator for 10 minutes and weighed. The results of weighing in grams are recorded to the fourth decimal place.

The corrosion rate (V) in g / m ² · h calculated by the formula:

$$V=\frac{m-m\mathrm{one}}{S*\tau },\left(\mathrm{one}\right)$$

where m is the mass of the plate before the test, g;

m1 is the mass of the plate after the test, g;

S is the plate area, m;

τ is the exposure time of the samples, h

The area of the plate (S) in square meters is calculated by the formula:

$$S=\frac{2\cdot \left(\mathrm{but}\mathrm{at}+\mathrm{but}\mathrm{from}+\mathrm{at}\mathrm{from}\right)}{\mathrm{one}000000}\left(2\right)$$

where a is the plate length, mm;

in - the width of the plate, mm;

C - plate thickness, mm. The area of the holes is neglected.

The test result is the arithmetic average of the results of three parallel determinations, the permissible differences between which should not exceed 0.04 g / m ² · h (P = 0.95).

Presented in table 6, the values of the rate of corrosion of steel in the claimed compositions, equal to 0.025-0.035 g / m ² hour, make it possible to classify carbon steel in accordance with a ten-point scale of corrosion resistance of metals (GOST 5272-50) to the group of resistant metals. This indicates a low corrosion activity of the proposed structure. In comparable conditions, the corrosion rate of the prototype reagent amounted to 0.37 g / m ² hour, which is more than an order of magnitude higher than the claimed composition. Carbon steel in the environment of the prototype belongs to the group of low-resistant metals on a scale of resistance of metals.

An important factor in choosing an inhibitor is the unit cost. For the claimed compositions, the costs of processing 1000 m ^{3 of} produced water were calculated at the declared efficiency values: 90% for the proposed composition, for the prototype, the efficiency level is 70% (Table 7).

As can be seen from table 7, the unit cost of treating 1000 m ^{3 of} produced water with the proposed compositions with an efficiency above 90% is 482-1054 rubles, while the prototype, having a higher unit cost of 1250 rubles, has an efficiency of only 70%.

In the field, the inhibitor is fed into the production well with a different ratio of hydrocarbon and water in the produced products. In this regard, the indicator of the distribution of the inhibitor in a two-phase oil / water system is an important criterion. Table 8 on the example of one of the compositions shows the analysis data on the content of the inhibitor in the aqueous phase of the oil-water mixture with varying degrees of water cut (30-70%). The results showed that the coefficient of transition of the inhibitor to the aqueous phase of the oil-water emulsion is 0.95-0.98, which also indicates the high efficiency of the claimed composition and its applicability in a wide range of water cut of the produced oilfield products.

Analysis of the data presented in tables 1, 5, 6, 7, shows that in the proposed composition, the technical result is achieved only in the claimed intervals of the components. The use of components in concentrations below the indicated intervals does not allow to achieve the desired result, and above the indicated intervals it is not advisable, since this only increases the cost of the composition without improving its properties.

The data presented in tables 5, 6, 7 and 8 show that the proposed scale inhibitor compared to the prototype is more effective, preventing the formation of insoluble carbonate and sulfate deposits in oilfield waters, exhibits low corrosion activity to metal equipment, which extends its duration operation, has a low freezing temperature, which allows it to be used in regions with a cold climate. The inventive composition in comparison with the prototype due to the low cost and high efficiency is more economical to use. The inventive composition is simple manufacturing technology. The process goes without heating and the formation of additional waste, which positively affects the technical and economic indicators of its production. In addition, the effective use in the proposed composition of the waste from the production of complexon Corilat solves the problem of their disposal. This allows you to reduce the burden on the environment and reduce the cost of production of scale composition by reducing the consumption rates of expensive and scarce components by more than 25%.

Table 1 Composition number Component composition, wt.% Appearance of the composition The drug Athos-300M Sodium hydroxide Ethylene glycol Thiocarbamide PAF-13A NTF one. 90.0 3.4 2.0 0.15 2.0 2.45 transparent liquid 2. 81.05 3.25 10.0 0.2 1,5 4.0 transparent liquid 3. 74.0 3.0 6.4 od 15.0 1,5 transparent liquid four. 75.0 3.0 6.0 0.1 13.0 2.9 transparent liquid 5 78.0 0.35 7.0 0.05 11.0 3.6 transparent liquid 6 84.0 0.3 1,5 0,03 12.87 1.3 sediment 7 88.35 3.0 1,2 0.05 1.4 6 sediment 8 70.0 2,5 10 0.15 14.0 3.35 muddy life 9 92 3,5 1.25 0.25 1,5 1,5 sediment 10 70 4.0 4.3 0.2 twenty 1,5 muddy life eleven 65 2.0 12.0 0.15 twenty 0.85 muddy life

table 2 No. p / p Field CO ₃ ^2- NSO ₃ ^- SO ₄ ^2- CL ^- Ca ²⁺ Mg ²⁺ Na ⁺ + K ⁺ mg / l one Tarasovskoe one 539 0 10298 866 69 5756 2 Festival 0 1084 0 13148 594 182 7864 3 Komsomolskoe 7 614 twenty 10493 428 137 6306 four New Purpe 22 498 25 9510 380 117 5731 5 Barsukovskoe fourteen 739 40 10426 381 135 6382

Table 3 Field Salt composition simulating carbonate deposits, g / l Mineralization g / l NaCl CaCl ₂ MgCl ₂ * 6H ₂ O NaHCO ₃ Na ₂ CO ₃ Tarasovskoe 14,108 2,397 0.577 0.742 0,000 17.52 Festival 18.94 1,644 1,521 1,492 0,000 22.79

Table 4 Field Salt composition simulating a mixture of carbonate and sulfate deposits, g / l Mineralization, g / l NaCl CaCl ₂ MgCl ₂ * 6H ₂ O Na ₂ SO ₄ NaHCO ₃ Na ₂ CO ₃ Komsomolskoe 15,400 1,184 1,145 0,030 0.845 0,000 17.79 New Purpe 13,998 1,052 0.978 0,025 0.686 0,039 16.77 Barsukovskoe 15,437 1,054 1,128 0,040 1.017 0,000 18.67

Table 5 The composition number from table 1 The concentration of the composition, mg / l The effectiveness of the composition to prevent salt deposits,%, a mixture of carbonate and sulfate deposits,% carbonate deposits,% Barsukovskoe New Purpe Komsomolskoe Festival Tarasovskoe one 10 89 87 86 90 90 twenty 90 89 89 93.5 93 thirty 92 90 89 94 96 2 10 89 83 86 92 90 twenty 89 87 91 92 90 thirty 90 89 90 91 90 3 10 88 86 87 92.5 93 twenty 90 89 87 97.5 93 thirty 91 90 89 97.5 92 four 10 91 90 88 90 94 twenty 92 90 89 93.5 95 thirty 93 92 91 98 97 5 10 91 90 89 95 95 twenty 93 93 91 97.5 96 thirty 94 93 92 98 98 6 10 89 87 86 88 90 twenty 90 89 89 89 91 thirty 92 90 89 89.5 93 7 10 89 83 86 81 80 twenty 89 87 91 83 81 thirty 90 89 90 83 83 8 10 89 87 86 86 88 twenty 90 89 89 87 88 thirty 92 90 89 88 89 9 10 78 76 77 75 74 twenty 78 78 78 76 75 thirty 80 79 80 77 76 10 10 74 76 73 81 80 twenty 75 78 75 84 83 thirty 77 79 78 86 85 eleven 10 80 81 87 85.5 85 twenty 82 83 87 86 87 thirty 87 85 89 90 89 Prototype 10 53 54 56 68 65 twenty 52 59 59 70 67 thirty 55 61 60 71 70

Table 6 The composition number in table 1 Pour point, ° C Corrosion rate, g / m ² hour one minus 40 0,020 2 minus 43 0,025 3 minus 46 0,030 four minus 41 0,025 5 minus 43 0,035 6 minus 33 0,050 7 minus 25 0,045 8 minus 37 0,033 9 sediment 0,035 10 sediment 0,028 eleven sediment 0.051 prototype minus 32 0.370

Table 7 The cost of processing 1000 m ^{3 of} produced water, rub. Prototype Suggested composition with the declared efficiency of 70% with declared efficiency of 90% and higher Consumption of the composition, kg The composition of the cost of the processing of 1000 m ³ of produced water, rub. The name of the composition from table 1 Consumption of the composition for processing, kg The composition of the cost of the processing of 1000 m ³ of produced water, rub. Narlex D54 -7.5 kg 5040USD / T * 30.7 rub. * 7.5 kg = 1160.5 rub. No. 1 10 482 PAF-13A-2.5 kg 36 rub * 2.5 kg = 90 rubles. Number 2 10 708 Number 3 10 962 Number 4 10 1020 Number 5 10 1054 Total cost: 1250.5 rub. (at prices of 2002) Total cost: 482-1054 rub. (at prices of 2013)

Table 8 The ratio in the emulsion The specific consumption of the inhibitor (composition No. 5 of table 1), mg / l The content of the inhibitor in the aqueous phase, mg / l The coefficient of transition of the inhibitor from emulsion to water nefras% formation water model% on emulsion to water thirty 70 fifteen 21,4 20.9 0.98 fifty fifty fifteen thirty 29.1 0.97 70 thirty fifteen fifty 47.5 0.95

Claims (1)

A composition for preventing inorganic salt deposits in oilfield equipment, including PAF-13A reagent, which is an aqueous solution of polyethylene polyaminomethylphosphonate with impurities of sodium chloride, acidic sodium salts of phosphoric and phosphoric acids, and ethylene glycol, characterized in that it additionally contains an aqueous solution of sodium nitrimetriethosulfonamide and hydrochloric acids - waste from the production of complexon Corilate, sodium hydroxide, nitrilotrimethylphosphonic acid (NTP), thiocarbamide when traveling ratio of components, wt.%:
reagent PAF-13A 1,5-15 aqueous solution of a mixture of sodium salts nitrilotrimethylphosphonic and hydrochloric acids - waste of complexon Corilat production 75-90 sodium hydroxide 0.35-3.4 nitrilotrimethylphosphonic acid (NTP) 1.5-4.0 thiocarbamide 0.05-0.2 ethylene glycol 2-10