RU2723809C1 - Composition for calcium salt prevention - Google Patents

Abstract

FIELD: oil, gas and coke-chemical industries.SUBSTANCE: invention relates to oil production, namely to compositions for preventing deposition of inorganic salts during oil production and transportation. Composition for preventing calcium salts, including nitrilotrimethylphosphonic acid - NTP, oxyethylenediphosphonic acid - OEDP, monoethanolamine - MEA, methanol and water, additionally contains modifier - neopentyl polyol containing in molecule neopentyl fragment - 2,2-bis(hydroxymethyl)propane-1,3-diol, 2,2-dimethylol propane or trimethylol propane, wherein NTP, OEDP and MEA it contains in form of a mixture in molar ratio of NTP/OEDP = 1.0–2.4 and molar ratio MEA/∑(NTP + OEDP) = 3.7–4.4, solvent in form of a mixture of methanol and water with weight ratio CHOH/HO = 0.4–1.0 at following ratio of components, wt. %: mixture of NTP, OEDP and MEA 30.2–33.7, modifier 0.5–2, solvent is the rest.EFFECT: technical result is higher efficiency relative to deposits of calcium carbonate and sulphate in conditions of high mineralization of formation water with provision of stability at low temperatures.1 cl, 26 ex, 4 tbl

Description

The invention relates to the field of oil production, in particular to compositions intended to prevent the deposition of inorganic salts (scale inhibitors) in wells and downhole equipment, as well as in a system for collecting, preparing and transporting oil.

The requirements for scale inhibitors relate both to their physicochemical (operational) and technological properties. They should be homogeneous liquids without phase separation, have a pour point not higher than minus 50 ° С, pH 6.9-9.5, density at 20 ° С not less than 0.95 g / cm ³ , corrosion aggressiveness (corrosion rate St-3 at 20 ° C for 24 h) not more than 0.1 g / (m ² ⋅ h), characterized by a kinematic viscosity at 20 ° C not more than 20 mm ² / s, at minus 40 ° C - not more than 500 mm ² / s. These compositions should be highly effective in preventing the deposition of salts (usually calcium carbonate and sulfate) under conditions of high mineralization, be compatible with the produced fluid (oil and produced water), killing fluid, and other chemicals used in the process of extraction, transportation and preparation of oil.

So, in Western Siberia, the used scale inhibitors must have cryostability (not freeze at temperatures above minus 50 ° C) and be well pumped at low temperatures.

A known composition for preventing deposits of salts of sulfate and calcium carbonate in oil production processes, including nitrilotrimethylphosphonic acid, polyacrylamide and water. SU 724550 A1, publ. 03/30/1980.

The disadvantage of this composition is the unsatisfactory effectiveness in highly mineralized environments.

A composition for preventing carbonate deposits, including hydroxyethylidene diphosphonic acid, alkanolamine, ethylene glycol and water, is described in RU 2122981 C1, publ. 12/10/1998.

The disadvantage is low efficiency in relation to calcium sulfate.

A known composition for preventing scaling, including nitrilotrimethylphosphonic acid, methyliminodimethylphosphonic acid, phosphorous acid, urea, ethylene glycol, ammonia and water. SU 1414794 A1, publ. 08/07/1988. This composition is also known as Incredol 1 scale inhibitor, manufactured according to TU 6-09-5363-87. However, such a composition is unstable over time and is not effective enough in conditions of high salinity of formation water.

A known composition for preventing carbonate deposits, including a phosphonic component, a water-soluble polymer, an amine component, a corrosion inhibitor, a hydroxyl-containing compound and water in the following ratio of components, wt.%: Phosphonic component - 5.0-30.0, water-soluble polymer - 0.1 -5.0, amine component - 5.0-20.0, corrosion inhibitor - 0.1-0.5, hydroxyl-containing compound - 5.0-30.0, water - the rest. As the hydroxyl-containing compound, methanol or ethanol or ethylene glycol or propylene glycol is used, and a maleic acid-acrylic acid copolymer, a polyacrylic acid sulfonate copolymer and a polyacrylic acid or polyacrylamide are used as a water-soluble polymer. RU 2447197 C1, 04/10/2012.

The disadvantage of the claimed composition is its complexity, the use of expensive polymers, low efficiency with respect to inorganic deposits of calcium salts, which is especially pronounced when using ethylene and propylene glycols (examples 4, 6, 7, 11), and, in addition, insufficiently low temperatures solidification. So, the pour point of the compositions according to examples 4 and 11 are minus 12 ° C and minus 36 ° C, respectively.

Closest to the proposed composition is a composition for the prevention of calcium scaling, providing high efficiency in preventing calcium deposits with high saturation ratios of mineralized waters and maintaining a low pour point. This composition contains, wt.%: Nitrilotrimethylphosphonic acid (NTP) - 15-25, hydroxyethylidene diphosphonic acid (HEDP) - 4-15, monoethanolamine (MEA) - 5-15, hydroxyl-containing compound (methanol or ethylene glycol) - 25-30, and water - the rest. RU 2179625 C1, publ. 02.20. 2002.

The disadvantage of this composition is the excess of the required kinematic viscosity at a temperature of minus 40 ° C (at a content of OEDP + MEA + NTF = 55 wt.%, The kinematic viscosity of the composition at a temperature of minus 40 ° C is 2095 cSt).

The technical task is to develop a composition for the prevention of calcium scaling - scaling inhibitor (IS), which is highly effective in relation to the deposition of calcium carbonate and sulfate in conditions of high salinity of formation waters with the requirements for physicochemical and technological properties: pour point not higher than minus 50 ° С, kinematic viscosity at 20 ° С not more than 20 mm ² / s, at minus 40 ° С - not more than 500 mm ² / s, phase stability at low temperatures, pH 6.9-9.5, density at 20 ° With not less than 0.95 g / cm ³ , corrosiveness not more than 0.1 g / (m ² ⋅ h), dosage not higher than 5-25 mg / dm ³ under conditions of measurements performed at a temperature of 35-95 ° С.

The technical result from the implementation of the invention is to provide high efficiency inhibition of deposits of calcium carbonate and sulfate in conditions of high salinity of formation water, ensuring compliance with the physicochemical and technological properties of the scale inhibitor regulatory requirements.

The technical result is achieved by the fact that the composition for preventing calcium scaling, including nitrilotrimethylphosphonic acid - NTF, hydroxyethylidene diphosphonic acid - HEDP and monoethanolamine MEA, methanol and water, according to the invention, it additionally contains a modifier - neopentylpolyol containing Neopentylpolymethine and MEA it contains as a mixture with a molar ratio of NTF / HEDP = 1.0-2.4 and a molar ratio of MEA / ∑ (NTF + HEDP) = 3.7-4.4, methanol and water as a mixture with mass the ratio of CH ₃ OH / N ₂ About = 0.4-1.0 in the following ratio of components, wt.%:

a mixture of NTF, HEDP and MEA with a molar ratio of NTF / HEDP = 1.0-2.4 and molar ratio MEA / ∑ (NTF + HEDP) = 3.7-4.4 30.2-33.7 modifier 0.5-2 solvent - a mixture of methanol with water, in a mass ratio CH ₃ OH / N ₂ O = 0.4-1.0 rest

The achievement of the technical result is also facilitated by the fact that, as a modifier, neopentylpolyol containing a nonopentyl fragment in the molecule, it contains 2,2-bis (hydroxymethyl) propane-1,3-diol (pentaerythritol), 2,2-dimethylolpropane (neopentyl glycol) or trimethylolpropane (ethriol).

All used components of the claimed composition for the prevention of calcium scaling are known products manufactured by the industry.

Oxyethylidene diphosphonic acid (OEDP) according to TU 6-02-1215-81;

Nitrilotrimethylphosphonic acid (NTP) according to TU 6-09-5283-86;

Monoethanolamine (MEA) according to TU 6-02-915-84;

Methanol according to GOST 6995-77 or GOST 2222-95;

2,2-Dimethylolpropane (neopentyl glycol) according to TU 2422-013-53505711-2005;

2,2-bis (hydroxymethyl) propane-1,3-diol (pentaerythritol) according to TU 9286-2012;

Trimethylolpropane (ethriol) according to TU 38.102101-76.

These signs are very significant. The claimed composition for the prevention of calcium scaling in the field of the stated ratios of the components provides a set of requirements for physical and chemical characteristics: pour point below minus 50 ° C, density at 20 ° C not lower than 0.95 g / cm ³ , kinematic viscosity at 20 ° With no more than 20 mm ² / s, kinematic viscosity at minus 40 ° C no more than 500 mm ² / s, pH 6.9-9.5, corrosiveness not more than 0.1 g / (m ² ⋅ h).

It is characterized by a wide range of compatibility with the water and oil phases and low salting out ability, it has significant technological efficiency at a reduced dosage of the composition due to improved adsorption and crystal-modifying salt properties.

Karvinen Е., Lehtonen J. Alcohols, Polyhydric,v. 2. Ullmann's Encyclopedia of Industrial Chemistry. - Weinheim: Wiley-VCH Verlag GmbH & Co. KGaA, 2012, p. 275. Neopentylglycol. MSDS (Material Safety Data Sheet), Perstorp. 2017, v. 2. Достоинством заявляемого состава для предотвращения кальциевых солеотложений является, кроме того, тот факт, что эффективность, которую проявляет добавка неопентилполиола, проявляется при ее весьма небольшом содержании - 0,5-2 мас.%.The presence of neopentyl polyol in the composition to prevent calcium scaling contributes to a more complete sorption of the reagent on the surface of the formed salt crystals and provides, in addition, an improvement in the environmental consequences of its use: neopentyl polyols are biodegradable, belong to low-hazard substances, and do not have the potential for bioaccumulation. Werle P., Morawietz M., Lundmark S.,

Karvinen E., Lehtonen J. Alcohols, Polyhydric, v. 2. Ullmann's Encyclopedia of Industrial Chemistry. - Weinheim: Wiley-VCH Verlag GmbH & Co. KGaA, 2012, p. 275. Neopentylglycol. MSDS (Material Safety Data Sheet), Perstorp. 2017, v. 2. The advantage of the claimed composition for the prevention of calcium scaling is, in addition, the fact that the effectiveness shown by the addition of neopentylpolyol is manifested with its very small content of 0.5-2 wt.%.

Thus, the analysis of the well-known technical solutions selected during the search showed that there is no object in science and technology that is similar in terms of the claimed combination of features and advantages, which allows us to conclude that its patentability is “novelty” and “inventive step”.

To prove the conformity of the proposed solution to the condition "industrial applicability" we give specific examples of the preparation of the composition and properties of the resulting compositions. The following examples do not limit the scope of the claims presented in the claims.

In accordance with the invention, the process of obtaining a composition for preventing calcium scaling consists in mixing pre-prepared mixtures of components that are taken in random order in quantities corresponding to a given composition.

Example 1. In a round-bottomed flask with a volume of 250 ml, equipped with a reflux condenser and a cooling water bath, a solvent was prepared — a mixture of methanol with water with a mass ratio of CH ₃ OH / H ₂ O = 0.79, mixing 29.3 g of methanol at room temperature and 37.1 g of water. A mixture of 13.1 g of NTF, 3.7 g of HEDP and 16.3 g of MEA, in which the molar ratio of NTF / HEDP = 2.4, the molar ratio of MEA, is added to the prepared solvent while cooling, while maintaining the mass temperature of 40-45 ° С. / ∑ (NTF + HEDP) = 4.3. The resulting mass is stirred for 10 minutes, then 0.5 g of pentaerythritol modifier is introduced. The mixture is stirred for 60 minutes at a temperature of 35 ° C. A homogeneous product is obtained without suspended and settling particles.

Examples 2-18 are performed analogously to example 1, changing the quantitative ratio of the components. The measurement results of the physicochemical properties of the obtained compositions are shown in table 1.

The obtained samples are homogeneous liquids that do not stratify into phases with a pour point below minus 50 ° C, with a density at 20 ° C of 1.072-1.165 g / cm ³ , and with corrosiveness less than 0.03 g / (m ² ⋅ h).

From table 1 it is seen that when the ratio of components, wt.%: A mixture of NTF, HEDP and MEA with a molar ratio of NTF / HEDP = 1.0-2.4 and a molar ratio of MEA / ∑ (NTF + HEDP) = 3.7- 1.4-30.2-33.7; the modifier is 0.5-2, the solvent (a mixture of methanol with water at a mass ratio of CH ₃ OH / H ₂ O = 0.4-1.0) - the rest, the composition of the combination of physico-chemical characteristics meet the requirements for the inhibitor compositions scaling.

Examples 19-21. The proposed composition of the IP specified in example 1, tested for the effectiveness of preventing deposits of carbonate and calcium sulfate in conditions of high salinity. In the tests, salt solutions are used to simulate the mineralized water of the deposits (model waters I-III), the composition of which is shown in Table 2. The effectiveness of preventing scaling is determined by the effective dosage of IP, providing inhibition of scaling on the specified salt solution with an efficiency of at least 90%. The test results of the inventive composition for inhibiting scaling are presented in table 3.

Analysis of the data in table 3 shows that the proposed composition effectively prevents salt deposits from mineralized waters of various compositions, and when using a dosage significantly reduced compared to the dosage of basic (commercial) scale inhibitors (examples 19-21).

Examples 22-26. The proposed IP compositions indicated in examples 1, 7, 16-18 are tested for the effectiveness of preventing deposits of carbonate and calcium sulfate under conditions of high content of bicarbonate anion (model water IV, table 2). The effectiveness of preventing scaling is determined at the same dosage of IP - 25 mg / DM ³ . The test results of the IP are presented in table 4.

Analysis of the data in table 4 shows that the presence of 0.5-2.0 wt.% Modifier (pentaerythritol, NPH or etriol) in the scale inhibitor leads to a significant increase in the efficiency of inhibition of scaling from 42% (example 22) to 65-91.2 % (examples 23-26) when using the same dosage.

Claims (2)

Composition for the prevention of calcium scaling, including nitrilotrimethylphosphonic acid - NTF, hydroxyethylidene diphosphonic acid - HEDP, monoethanolamine - MEA, methanol and water, characterized in that it additionally contains a modifier - neopentylpolyol containing in the molecule neopentyl-bisimet (2,2-hydroxymethyl) - propane-1,3-diol, 2,2-dimethylolpropane or trimethylolpropane, and it contains NTF, HEDP and MEA as a mixture with a molar ratio of NTF / HEDP = 1.0-2.4 and a molar ratio of MEA / ∑ (NTF + OEDP) = 3.7-4.4, a solvent in the form of a mixture of methanol and water with a mass ratio of CH ₃ OH / H ₂ O = 0.4-1.0 in the following ratio of components, wt.%: a mixture of NTF, OEDP and MEA 30.2-33.7 modifier 0.5-2 solvent rest