Heavy well kill fluid containing calcium bromide and method for producing same

Abstract

The invention relates to the field of the oil production industry, and more particularly to heavy well kill fluids containing calcium bromide and to methods for producing same. The claimed method makes it possible to produce a heavy well kill fluid using, as feedstock, accessible solutions of calcium chloride and sodium bromide, wherein the resulting fluid has the necessary properties for effectively killing wells. The claimed method includes mixing solutions of calcium chloride and sodium bromide where the molar ratio of calcium chloride to sodium bromide is 0.9-1.3:2, evaporating the resulting mixed solution to a density of 1400-1800 kg / m3, cooling the evaporated solution to a temperature of less than 25°C to form crystals of sodium chloride, and filtering the evaporated solution to obtain a filtrate in the form of a heavy well kill fluid.

Description

[0001] HEAVY WELL KILLING FLUID CONTAINING CALCIUM BROMIDE AND A METHOD FOR ITS PRODUCTION

[0002] Field of technology.

[0003] The invention relates to the field of oil production industry, in particular to heavy well killing fluids containing calcium bromide, and methods for producing them.

[0004] State of the art.

[0005] Heavy well killing fluids, or heavy killing fluids, or heavy process fluids, are used to create back pressure on the formation in order to prevent the influx of fluids or gases into the well; such measures can be carried out for well repair and maintenance, as well as in a number of emergency situations.

[0006] In the oil production industry, heavy well-killing fluids based on calcium compounds and bromine-containing salts have become widely used.

[0007] The prior art discloses a process fluid for major well repairs, according to patent RU2599395C1 [1], which can be used in conditions of abnormally high formation pressures for killing and preserving wells.

[0008] This process fluid contains, by weight %:

[0009] Polyhydric alcohol - 10-15;

[0010] CaBr2- 20-50;

[0011] ZnBr2or Znl2- 20-50;

[0012] Water is the rest.

[0013] The disadvantages of this process fluid include the high cost of the components included in its composition, while the invention does not disclose an accessible method for producing calcium bromide.

[0014] A heavy process fluid for killing wells is known from the prior art according to patent RU2731965C1 [2], which is obtained by dissolving 35-41 wt.% calcium nitrate in water and adding calcium bromide to obtain fluids with densities from 1580 to 1820 kg / m3.3 at 20 °C.

[0015] The disadvantage of this well killing fluid is the use of expensive components in its composition, while the invention does not disclose an accessible method for producing calcium bromide.

[0016] The heavy liquid according to patent RU2731965C1 [2] and the method for its production are the closest to the technical solutions according to the claimed invention.

[0017] A blocking fluid for killing wells is known from the prior art according to patent RU2104392C1 [3], this blocking fluid contains, by weight %:

[0018] Water-soluble calcium salt, which can be calcium bromide - 12.5 - 43.5;

[0019] Free ammonia - 0.1 - 2.0;

[0020] Waste from the pulp and paper industry based on lignosulfonates - 5.0 - 25.0;

[0021] Wood flour - 4.0 - 12.0;

[0022] Water is the rest.

[0023] The disadvantages of this blocking fluid include the high cost of the calcium bromide component included in its composition, while the invention does not disclose an accessible method for its production.

[0024] The prior art discloses a composition according to patents US4304677A [4] and US4292183A [5], which contain calcium bromide and zinc bromide, but the patents do not disclose a method for producing calcium bromide. A disadvantage of these compositions is the high cost of the components included in their composition.

[0025] The prior art discloses a composition for preparing process fluids according to patent RU2005762C1 [6], which can be used to kill oil and gas wells.

[0026] The composition for the preparation of process fluids includes a water-soluble calcium salt, which can be presented in the form of calcium bromide, free ammonia, water, technical lignosulfonate or neutral sulfite lye.

[0027] The disadvantages of this composition include the high cost of the components included in it.

[0028] The examples of this invention describe a method for producing calcium bromide for the preparation of a process fluid based on it according to the scheme set out in patent SU1189868A1 [7], which will be discussed below.

[0029] A solution for the preparation of high-density process fluids is known from the prior art according to patent SU1189868A1 [7], this solution contains, by weight %:

[0030] Calcium bromide - 57 - 59;

[0031] Calcium hydroxide - 0.2 - 0.4;

[0032] Free ammonia - 0.2 - 0.4; Water - the rest.

[0033] The preparation of a calcium bromide solution for the preparation of process fluids based on it is carried out according to the following scheme:

[0034] H2O + Ca(OH)2+ Br2+ NH4OH -> CaBr2+ N2+ H2O + Ca(OH)2+ NH4OH.

[0035] The disadvantages of this process fluid include the high cost of the components included in its composition, while the presented method for obtaining a calcium bromide solution has a number of disadvantages, in particular, the use of molecular bromine, which is a toxic substance, increases the level of danger of such production, and the ammonia remaining in the solution, albeit in small quantities, after the reaction is a corrosive component.

[0036] As can be seen from the examples provided, the use of calcium bromide in well-killing solutions is effective and is a common practice. However, the identified technical solutions do not disclose accessible and safe methods for obtaining this component.

[0037] The essence of the invention.

[0038] The aim of the present invention is to obtain a heavy well killing fluid containing calcium bromide using readily available and inexpensive raw materials.

[0039] This goal is achieved by using calcium chloride and sodium bromide solutions to produce a heavy well killing fluid, which has the necessary characteristics for effective well killing.

[0040] The stated objective is achieved by the fact that the extraction and processing of calcium chloride brines, from which products in the form of calcium chloride and sodium bromide solutions can be obtained, is carried out in areas where drilling is carried out for the purpose of oil and gas production, which makes it possible to obtain and use heavy drilling fluid obtained by the stated method with the minimization of costs for its production and transportation to the place of use.

[0041] The stated objective is achieved in that the method for producing a heavy well killing fluid containing calcium bromide includes: mixing solutions of calcium chloride and sodium bromide at a molar ratio of calcium chloride to sodium bromide of 0.9 - 1.3:2; evaporation of the solution obtained as a result of mixing to a density of 1400 - 1800 kg / m3 3 ; cooling the evaporated solution to a temperature below 25 °C to form sodium chloride crystals; filtering the evaporated solution to obtain a filtrate in the form of a heavy well killing fluid and a cake in the form of sodium chloride crystals.

[0042] The stated objective is achieved by the fact that, according to one embodiment of the invention, solutions of calcium chloride and sodium bromide have a temperature of 65 to 95 °C, and before evaporation, the solution obtained as a result of mixing them is filtered.

[0043] The stated objective is achieved by the fact that, according to one embodiment of the invention, the cake separated as a result of filtration in the form of sodium chloride crystals is washed with water, and the water after washing the sodium chloride crystals is sent for evaporation together with the solution obtained as a result of mixing.

[0044] The stated objective is achieved by the fact that, according to one embodiment of the invention, after cooling the evaporated solution and before filtering it, the solid phase in the form of precipitated sodium chloride crystals is separated by centrifugation or settling.

[0045] The stated objective is achieved by the fact that, according to one embodiment of the invention, the obtained well killing fluid is evaporated to obtain a dry product, after which, by dissolving the dry product in water, the well killing fluid is again obtained.

[0046] The technical result consists in obtaining a liquid containing calcium bromide, possessing the necessary characteristics for the effective killing of wells, using inexpensive and readily available raw materials in an effective manner, the technical result also consists in the resulting reduction in the cost of such a killing liquid.

[0047] The technical result is achieved by using calcium chloride and sodium bromide solutions as the initial components for obtaining a calcium bromide solution, which are accessible and inexpensive raw materials, especially in the case of their production as a by-product of processing natural calcium chloride brines.

[0048] The technical result is achieved by mixing calcium chloride and sodium bromide solutions at a molar ratio of calcium chloride to sodium bromide of 0.9 - 1.3:2, which ensures an effective reaction to obtain the required amount of calcium bromide in the solution. The technical result is achieved by evaporating the solution obtained as a result of mixing to a density of 1400-1800 kg / m3. 3 provides the required density of the resulting heavy well killing fluid, which makes it possible to effectively use it for its intended purpose.

[0049] The technical result is achieved by evaporating the solution obtained as a result of mixing to a density of 1400 - 1800 kg / m3 3 and subsequent cooling to a temperature below 25°C ensures effective salting out of sodium chloride, which allows for its most complete removal from the calcium bromide solution and prevents the equipment from becoming clogged with its crystals.

[0050] The technical result is achieved by the fact that filtration of the evaporated and cooled calcium bromide solution allows for its most complete separation from sodium chloride crystals and prevents equipment from becoming clogged.

[0051] The technical result can be achieved by using calcium chloride and sodium bromide solutions at temperatures ranging from 60 to 95°C. This allows for the use of more saturated solutions due to their greater solubility in hot water. This accelerates the reaction, saves heat transfer fluid and time during the subsequent evaporation of the solution, and reduces water consumption during the preparation of calcium chloride and sodium bromide solutions. In this method, after mixing the hot calcium chloride and sodium bromide solutions but before evaporation, filtration is performed to separate a portion of the sodium chloride, simplifying further processing of the mixed solution.

[0052] The technical result can be achieved by the fact that, when implementing the invention, the cake obtained during filtration operations can be dissolved in water in the form of sodium chloride, followed by its introduction into the formation, which ensures the utilization of sodium chloride and the use of its solution to meet the needs of operation or drilling of wells, which increases the economic effect of the process.

[0053] The technical result can be achieved by the fact that, when implementing the invention, the cake obtained in the filtration operations can be separated in the form of sodium chloride, washed with water and dried, which makes it possible to obtain a separate product in the form of sodium chloride and increase the economic effect of the process, while washing the sodium chloride crystals increases the purity of the product.

[0054] The technical result can be achieved by the fact that, when implementing the invention, water can be directed after washing the sodium chloride crystals for evaporation together with the solution obtained as a result of mixing, which reduces the loss of bromine and calcium and increases the efficiency of the process.

[0055] The technical result can be achieved in that, when implementing the invention, after cooling the evaporated solution and before filtering it, the solid phase in the form of precipitated sodium chloride crystals can be separated by centrifugation or settling, which ensures the effective separation of sodium chloride from the calcium bromide solution and makes it possible to reduce the load on the filters at the filtration stage, which simplifies the process of separating sodium chloride and increases the cost-effectiveness of the process.

[0056] The technical result can be achieved by the fact that, when implementing the invention, the sodium chloride obtained during settling or centrifugation operations can be separated, washed with water and dried, which makes it possible to obtain a separate product in the form of sodium chloride and increase the economic effect of the process, while washing the sodium chloride crystals increases the purity of the product.

[0057] The technical result can be achieved by the fact that, when implementing the invention, the obtained heavy well-killing fluid can be dehydrated to obtain a dry product, and then, by dissolving the dry product in water, a well-killing fluid can be obtained, which increases the commercial properties of the heavy well-killing fluid, due to the possibility of selling it in dry form and transporting it to the place of use.

[0058] The technical result can be achieved in that, when implementing the invention, the obtained heavy well killing fluid can be used as a base for creating other fluids for killing and servicing wells, ensuring drilling, for which purpose additional components are introduced into the obtained heavy well killing fluid; the use of such a base ensures a reduction in the cost of the final fluid.

[0059] The technical result is achieved in that the heavy well killing fluid obtained according to any embodiment of the invention has the necessary characteristics, including density, to create the necessary back pressure on the formation in order to prevent the influx of fluids or gases into the well and kill the well.

[0060] In its most general form, the method of the present invention can be carried out as follows, but is not limited thereto.

[0061] Description of the drawings. Fig. 1. General diagram of the method.

[0062] Fig. 2. Particular diagram of the method implementation.

[0063] Fig. 3. Particular diagram of the method implementation.

[0064] Fig. 4. Scheme of the method implementation. Example 1.

[0065] The general flow chart of the method is shown in Fig. 1. To implement the method, a sodium bromide solution and a calcium chloride solution are mixed while maintaining a molar ratio of calcium chloride to sodium bromide of 0.9 - 1.3:2. Mixing can be carried out in a flow-type reactor, a perfectly stirred tank reactor, or another type of reactor that ensures effective mixing of the solutions. During the mixing of the sodium bromide solution and the calcium chloride solution, a reaction occurs with the formation of calcium bromide and sodium chloride, while calcium bromide remains dissolved, and sodium chloride, depending on the concentrations of the original solutions, may partially precipitate. The resulting solution is sent for evaporation, where the density of the solution is brought to 1400-1800 kg / m3. 3, and then cooled to a temperature below 25 °C, during which sodium chloride actively precipitates from the solution, the cooled solution is sent for filtration to separate it from the sodium chloride crystals and after filtration a heavy liquid suitable for killing wells is obtained.

[0066] A specific flow chart of the method is shown in Fig. 2. To implement the method, a sodium bromide solution with a temperature of 60 to 95 °C and a calcium chloride solution with a temperature of 60 to 95 °C are mixed while maintaining a molar ratio of calcium chloride to sodium bromide of 0.9-1.3:2. Mixing can be carried out in a flow-through reactor, a perfectly stirred tank reactor, or another type of reactor that ensures effective mixing of the solutions. During the mixing of the sodium bromide solution and the calcium chloride solution, a reaction occurs to form calcium bromide and sodium chloride. The calcium bromide remains dissolved, and the sodium chloride, depending on the concentrations of the initial solutions, may partially precipitate. The resulting solution is filtered to remove any sodium chloride crystals that may have precipitated as a result of the reaction. After filtration, the solution is sent for evaporation, where the density of the solution is brought to 1400-1800 kg / m33, and then cooled to a temperature below 25 °C, during which sodium chloride actively precipitates from the solution. The cooled solution is sent for filtration to separate the sodium chloride crystals, and after filtration, a heavy liquid suitable for killing wells is obtained. Another particular scheme for implementing the method is shown in Fig. 3. To implement the method, a sodium bromide solution with a temperature of 60 to 95 °C and a calcium chloride solution with a temperature of 60 to 95 °C are sent for mixing while maintaining a molar ratio of calcium chloride to sodium bromide of 0.9-1.3:2. Mixing can be carried out in a flow-through reactor, a perfectly mixed reactor, or another type of reactor that ensures effective mixing of the solutions.When mixing sodium bromide and calcium chloride solutions, a reaction occurs, forming calcium bromide and sodium chloride. The calcium bromide remains dissolved, while the sodium chloride may partially precipitate, depending on the concentrations of the original solutions. The resulting solution is filtered to remove any sodium chloride crystals that may have precipitated during the reaction. The filter cake is sent to a sodium chloride storage tank. After filtration, the solution is evaporated, where the density is adjusted to 1400-1800 kg / m3. 3 , and then cooled to a temperature below 25 °C, during which sodium chloride actively precipitates from the solution, which is separated, the cooled solution is sent for filtration to separate the sodium chloride crystals, the filter cake is sent to a sodium chloride storage tank, after filtration a heavy liquid is obtained suitable for killing wells.

[0067] The first portion of the heavy well killing fluid is directed into the first well to perform the killing.

[0068] The second portion of the heavy well killing fluid is sent for mixing with additional components, after which it is fed into the second well for killing.

[0069] The third part of the heavy well killing fluid is sent for evaporation to obtain a dry product of heavy well killing fluid (dry product of HWK), which is dissolved in water as needed and used as heavy well killing fluid in the third well.

[0070] Part of the sodium chloride collected in the storage tank is dissolved in water and used as a fluid in the reservoir pressure maintenance system.

[0071] Part of the sodium chloride collected in the storage tank is sent for washing with water, and after washing it is dried to obtain a commercial product in the form of sodium chloride crystals.

[0072] After washing the sodium chloride, the water is sent to the evaporation stage of the solution obtained by mixing the sodium bromide and calcium chloride solutions. Specific examples of implementing the method according to the present invention are provided below.

[0073] Example 1.

[0074] The production of heavy well killing fluid was carried out according to the scheme shown in Fig.4.

[0075] A flow-type mixing reactor was fed with 11.9 kg of a 42% calcium chloride solution and 20.67 kg of a 45% sodium bromide solution. The CaChiNaBr molar ratio in the initial mixtures was maintained at 1:2.

[0076] As a result of mixing the two streams in a flow-type reactor, a solution of calcium bromide with sodium chloride was formed, which was sent for evaporation to an evaporator to a density of 1680 kg / m3. 3 .

[0077] After evaporation, the hot mixture was cooled to a temperature of 20-25 °C, then filtered to remove the sediment.

[0078] A filtrate weighing 16.8 kg was obtained with the following composition: calcium bromide - 43.7%, water - 45.1%, density - 1680 kg / m3 3 , chlorides - 4%, sodium - 1%.

[0079] The resulting filtrate was used as a heavy fluid for killing the well.

[0080] The filtration also yielded a cake of sodium chloride crystals (5.03 kg of sodium chloride on a dry basis), which was washed with water and dried, yielding 4.5 kg of commercial sodium chloride. The water after washing the sodium chloride was sent to an evaporator.

[0081] The steam obtained in the evaporation plant was cooled in a heat exchanger with the recovery of thermal energy into the system and the release of condensate; the condensate was used to wash sodium chloride crystals.

[0082] Example 2.

[0083] 11.9 kg of a 42% calcium chloride solution with a temperature of 60°C and 18.54 kg of a 50% sodium bromide solution with a temperature of 90°C were fed into a perfectly mixed reactor.

[0084] The CaChiNaBr molar ratio in the initial mixtures was maintained at 1:2. The resulting reaction mixture was stirred in a perfectly stirred reactor for 20 minutes, after which the resulting mixture was filtered to remove the precipitate.

[0085] After filtration, the precipitate, which was sodium chloride weighing 1.81 kg (in terms of dry product), was separated, and the filtrate was fed for evaporation into an evaporator to a density of 1700 kg / m3. 3 .

[0086] After evaporation, the hot mixture was cooled to a temperature of 20 °C, then filtered from the sediment, separating 3.36 kg of sodium chloride (calculated as dry product).

[0087] We obtained a filtrate weighing 16.3 kg of the following composition:

[0088] Composition data of the commercial product: calcium bromide - 48.4%, water - 44.0%, density - 1705 kg / m3 3 , chlorides - 3.5%, sodium - 0.5%.

[0089] The resulting filtrate was used as a heavy fluid for killing the well.

[0090] The sodium chloride separated on the filters was sent for washing and drying.

[0091] The sodium chloride was washed with water and dried, yielding 4.7 kg of commercial sodium chloride. The water after washing the sodium chloride was sent to an evaporator.

[0092] The steam obtained in the evaporation plant was cooled in a heat exchanger with the recovery of thermal energy into the system and the release of condensate; the condensate was used to wash sodium chloride crystals.

[0093] Example 3.

[0094] The production of a heavy well killing fluid was carried out similarly to Example 1, with the difference that the solution was evaporated to a density of 1400 kg / m3. 3 .

[0095] As a result, we obtained 24.6 kg of heavy well killing fluid of the following composition: calcium bromide - 32.1%, water - 36.0%, density - 1400 kg / m3 3 , chlorides - 20.0%, sodium - 4.7%.

[0096] Example 4.

[0097] The production of a heavy well killing fluid was carried out similarly to Example 1, with the difference that the solution was evaporated to a density of 1800 kg / m3. 3 .

[0098] As a result, we obtained 13.3 kg of heavy well killing fluid of the following composition: calcium bromide - 50.7%, water - 40.2%, density - 1800 kg / m3 3 , chlorides - 4.5%, sodium - 0.2%.

[0099] Example 5.

[0100] The production of a heavy well killing fluid was carried out similarly to Example 4, with the difference that solutions of calcium chloride and sodium bromide were mixed at a molar ratio of calcium chloride to sodium bromide of 0.9:2.

[0101] As a result, we obtained 17.4 kg of heavy well killing fluid of the following composition: calcium bromide - 54.9%, water - 32.9%, density - 1715 kg / m3 3 , chlorides - 6.2%, sodium - 0.6%.

[0102] Example 6.

[0103] The production of a heavy well killing fluid was carried out similarly to Example 4, with the difference that solutions of calcium chloride and sodium bromide were mixed at a molar ratio of calcium chloride to sodium bromide of 1.3:2.

[0104] As a result, we obtained 18.5 kg of heavy well killing fluid of the following composition: calcium bromide - 36.6%, water - 27.8%, density - 1759 kg / m3 3 , chlorides - 22.6%, sodium - 0.18%.

[0105] Example 7.

[0106] The production of a heavy well killing fluid was carried out similarly to Example 1, with the difference that after cooling the evaporated solution and before filtering it, the solid phase in the form of precipitated sodium chloride crystals was separated by settling and then centrifugation, which made it possible to reduce the hydraulic resistance on the filters.

[0107] The sodium chloride crystals separated by centrifugation were also washed and dried, yielding 4.6 kg of commercial sodium chloride.

[0108] Example 8.

[0109] Heavy well-killing fluid was produced similarly to Example 1, with the difference that the process was calculated to yield 3,000 kg of heavy well-killing fluid. After this amount of fluid was produced, it was used at the field for its intended purpose. Example 9.

[0110] The production of heavy well killing fluid was carried out in a manner similar to Example 7, with the difference that the obtained heavy well killing fluid was evaporated to obtain a dry product, which was transported to the field, then by dissolving the dry product in water, heavy well killing fluid was again obtained, which was then used.

[0111] Example 10.

[0112] The production of a heavy well killing fluid was carried out in a manner similar to Example 7, with the difference that zinc bromide was added to the resulting heavy well killing fluid.

[0113] Sources of information used.

[0114] 1. Patent RU2599395C1. IPC C09K 8 / 42. Technological fluid for well workover / Gaidarov Azamat Mitalimovich, Norov Azat Davronovich, Khubbatov Andrey Atlasovich, Gaidarov Mitalim Magomed-Rasulovich, Alekseeva Nina Viktorovna. Application dated 05.06.2015, published 10.10.2016.

[0115] 2. Patent RU2731965C1. MPK S09K 8 / 42. Heavy process fluid for killing wells, composition and method for its preparation / Karpov Alexey Aleksandrovich, Kunakova Anisa Mukhametgalimovna, Kaybyshev Ruslan Radikovich, Puchina Gulfiya Rashitovna, Sergeeva Natalya Anatolyevna, Ragulin Viktor Vladimirovich. Application dated 09.09.2019, published. 09.09.2020.

[0116] 3. Patent RU2104392C1. IPC E21B 43 / 12, C09K 7 / 02. Method of killing a well and blocking fluid for killing a well / Baranov Yu.V., Ziyatdinov I.Kh., Valeeva T.G. Application dated 06.05.1996, published 10.02.1998.

[0117] 4. Patent US4304677A. IPC C09K8 / 16. Method for servicing wellbores / Randall S. Stauffer, Andrew J. Pastor. Application dated 05.09.1978, published 08.12.1981.

[0118] 5. Patent US4292183A. IPC C09K8 / 04. High-density liquid compositions / David S. Sanders. Application dated 13.12.1978, published 29.09.1981.

[0119] 6. Patent RU2005762C1. MPK S09K 7 / 02. Composition for the preparation of technological liquids / Ziyatdinov I.Kh., Valeeva T.G., Verderevsky Yu.L., Arefyev Yu.N., Reshetov P.P., Khakimzyanova M.M. Application dated 05 / 13 / 1992, publ. 01 / 15 / 1994. 7. Patent SU1189868A1. MPK S09K 7 / 04. Solution for the preparation of technological liquids / Ryabokon S.A., Brazhnikov A.A., Lukovnikov V.P., Rilo R.P., Ulyanov D.G. Application dated 03 / 02 / 1984, publ. 11 / 07 / 1985.

Claims

CLAUSES OF THE INVENTION 1. A method for producing a heavy well killing fluid containing calcium bromide, comprising: mixing solutions of calcium chloride and sodium bromide at a molar ratio of calcium chloride to sodium bromide of 0.9-1.3: :2; evaporating the solution obtained as a result of mixing to a density of 1400-1800 kg / m3 3 ; cooling the evaporated solution to a temperature below 25 °C to form sodium chloride crystals; filtering the evaporated solution to obtain a filtrate in the form of a heavy well killing fluid and a cake in the form of sodium chloride crystals.

2. The method according to paragraph 1, characterized in that the mixed solutions of calcium chloride and sodium bromide have a temperature of 60 to 95°C, and before evaporation, the solution obtained as a result of their mixing is filtered.

3. The method according to paragraph 1 or 2, characterized in that the cake separated as a result of filtration in the form of sodium chloride crystals is washed with water, which, after washing the sodium chloride crystals, is sent for evaporation together with the solution obtained as a result of mixing.

4. The method according to paragraph 1, characterized in that after cooling the evaporated solution and before filtering it, the solid phase in the form of precipitated sodium chloride crystals is separated by centrifugation or settling.

5. The method according to paragraph 1, characterized in that the obtained heavy well killing fluid is evaporated to obtain a dry product, after which, by dissolving the dry product in water, a heavy well killing fluid is again obtained.

6. A heavy well killing fluid based on water and calcium bromide, also containing chlorides and sodium, which is a filtrate cooled to a temperature of less than 25°C and evaporated to a density of 1400-1800 kg / m3 3a solution obtained by mixing solutions of calcium chloride and sodium bromide at a molar ratio of calcium chloride to sodium bromide of 0.9-1.3:

2.

7. The liquid according to paragraph 6, characterized in that the mixed solutions of calcium chloride and sodium bromide have a temperature of 60 to 95°C, and the solution obtained by mixing the solutions of calcium chloride and sodium bromide is additionally filtered before evaporation.

8. The liquid according to paragraph 6, characterized in that the solid phase in the form of precipitated sodium chloride crystals was separated from the evaporated solution after cooling and before its filtration by centrifugation or settling.

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