Antifoam for drilling and cementing fluids

Abstract

The invention relates to the oil production industry, and more particularly to compositions and methods for treating drilling and cementing fluids in order to suppress foam formation and break down existing foam. According to one embodiment, an antifoam composition comprises heavy pyrolysis tar and an active additive, wherein the active additive is oleic acid, stearic acid or a mixture thereof. According to a second embodiment, an antifoam composition comprises a hydrocarbon solvent and an active additive in the form of oleic acid. Also described are methods for the use of said compositions to suppress foam formation and break down existing foam. The claimed compositions make it possible to suppress foam and prevent foam formation in drilling and cementing fluids using accessible and compatible substances.

Description

[0001] Antifoam agent for drilling and cementing muds

[0002] Field of technology.

[0003] The invention relates to the field of the oil producing industry, in particular to compositions and methods for treating drilling and cementing solutions in order to suppress foaming and destroy foam that has already formed.

[0004] State of the art.

[0005] The use of drilling fluids during the drilling process provides cooling and lubrication of the bit, removal of drill cuttings, and the creation of hydrostatic pressure on the drilled formations to prevent the flow of liquids and gases from them into the wellbore.

[0006] Cementing slurries are combinations of special materials or compositions used for plugging oil and gas wells.

[0007] During drilling and plugging operations, a number of solutions are characterized by the phenomenon of active foaming; this effect can also be enhanced under conditions of gas production, active pumping of solutions and their contamination with foaming impurities.

[0008] Excessive foaming in the drilling fluid leads to a decrease in the efficiency of pumping equipment, a decrease in the density of the drilling fluid, a decrease in the circulation of the fluid through the well, and a decrease in its lubricating and cooling properties.

[0009] Excessive foaming in the cement slurry also leads to a decrease in the efficiency of pumping equipment, a decrease in the density of the slurry, a decrease in the circulation of the slurry, the formation of unacceptable cavities and incomplete filling of the areas being plugged, and a decrease in the quality of cementing.

[0010] In order to eliminate these negative effects, various methods of suppressing foam formation and foam destruction are used.

[0011] A composition for reducing foaming in drilling fluids is known from the prior art according to UK patent 1

[0012] SUBSTITUTE SHEET (RULE 26) GB2543451B [1], comprising hydrophobic silicon dioxide and an organic acid ester of a polyoxyethylene-polyoxypropylene block copolymer. This composition reduces foaming, but its disadvantages include decreased defoaming properties of the finished composition during long-term storage with wide temperature fluctuations, and low defoaming ability when processing salt-saturated polymer drilling fluids.

[0013] A defoamer for drilling fluids is known from the prior art according to the USSR patent SU1167192A1 [2], which contains an oil product, a defoaming base, an emulsifier and water, while a powder composition containing an organosilicon liquid, liquid glass and a salt of a multivalent metal is used as the defoaming composition.

[0014] The use of this composition reduces foaming, but its disadvantages include the instability of the resulting liquids during storage and the need to use an emulsifier to obtain a stable composition, which in turn can reduce the antifoam properties.

[0015] A defoamer-antifoamer is known from the prior art according to the Russian Federation patent RU2155202C2 [3], containing a defoaming base and a hydrocarbon solvent, characterized in that it contains colloidal calcium or aluminum silicates, or aqueous-alcoholic solutions of sodium ethyl (methyl) siliconates, or tall oil sludge-lignin as a defoaming base, and diesel fuel with a density of 0.79 - 0.86 g / cm as a hydrocarbon solvent. 3and an iodine number of n = 2-6, and additionally, an emulsifier—light tall oil—and water. A disadvantage of this composition for defoaming purposes is the high cost of the components, primarily due to the presence of diesel fuel, as well as the potential crosslinking of drilling and cement slurry components due to the presence of divalent and trivalent metal cations.

[0016] A composition of an antifoaming agent is known from the prior art according to the Russian Federation patent RU2495901C2 [4], which contains water, polydimethylsiloxane, methylcellulose, hydroxyethylcellulose, amorphous silicon dioxide and 2

[0017] SUBSTITUTE SHEET (RULE 26) Cu-Cig mono- and diglycerides. The disadvantages of this composition include low stability in drilling fluids with a pH greater than 10 and poor dispersibility of the active component (polydimethylsiloxane) in an aqueous system.

[0018] As can be seen from the examples given, defoaming compositions for drilling fluids have found wide application in the oil and gas industry, while the technical solutions known from the prior art have a number of disadvantages that limit the scope of their use.

[0019] The essence of the invention.

[0020] The aim of the present invention is to obtain a defoaming composition for drilling and cementing fluids that provides the required functional properties, using accessible and compatible raw materials as its base.

[0021] The stated objective is achieved by the fact that the defoaming compositions for drilling and plugging mud with the compositions described in the present invention contain available pyrolysis products from the chemical and oil and gas industries, while the defoamers provide the necessary level of functional qualities for their wide application in drilling and plugging.

[0022] The stated objective is achieved in that, according to one of the variants, the defoaming composition is a heavy pyrolysis resin and an active additive, wherein the active additive is oleic acid, stearic acid or a mixture thereof, wherein the composition may contain said components in the following wt.% ratio: heavy pyrolysis resin - 55 - 94, active additive - 6 - 45, wherein the composition may additionally contain one or more components: (i) monohydric alcohols of the aliphatic series in an amount of 5-10 wt.%; (ii) a mixture of polyethylene glycol ethers in an amount of 1-5 wt.%; (iii) a kerosene-gas oil fraction of straight distillation of petroleum in an amount of 10-32 wt.%.

[0023] The stated objective is achieved by the fact that, according to one of the variants, the defoaming composition is a hydrocarbon solvent and an active additive in the form of oleic acid, while the composition can 3

[0024] SUBSTITUTE SHEET (RULE 26) contain the specified components in the following ratio by weight: hydrocarbon solvent - 60 - 95, active additive - 5 - 40, wherein the composition may additionally contain one or more components: (i) monohydric alcohols of the aliphatic series in an amount of 5-15 wt.%; (ii) a mixture of polyethylene glycol ethers in an amount of 1-5 wt.%; (iii) kerosene-gas oil fraction of straight distillation of petroleum in an amount of 5-20 wt.%.

[0025] The stated objective is achieved by the fact that the presented variants of the defoaming composition are introduced into the drilling or cementing solution, and the composition can be introduced in an amount from 0.01 to 2% of the mass of the drilling or cementing solution.

[0026] The stated goal is achieved by the fact that components in the form of heavy pyrolysis resin, oleic acid and stearic acid (or their mixture) can be introduced separately or together into the drilling or cementing solution.

[0027] The stated goal is achieved by the fact that components in the form of a hydrocarbon solvent and oleic acid can be separately or jointly introduced into the drilling or cementing solution.

[0028] The technical result consists in ensuring foam suppression and preventing foam formation in drilling and cement slurries using defoaming compositions that include available and compatible substances.

[0029] The technical result also consists of an additional lubricating effect, which is provided for the drilling fluid when introducing variants of the composition into it.

[0030] The technical result is achieved by using heavy pyrolysis resin (grades A and B) as a component of the antifoaming composition. It is an optimal carrier for functional additives of any type, as it is a relatively pure petroleum product, contains no foreign reactive compounds or groups, and provides the necessary synergistic effect with oleic and stearic acids, as well as surfactants, ensuring a high degree of dispersion in an aqueous medium.

[0031] 4

[0032] SUBSTITUTE SHEET (RULE 26) Heavy pyrolysis resin is produced by the pyrolysis of low-octane gasolines and gas oils to produce significant quantities of ethylene and propylene, as well as by the pyrolysis of gas feedstocks, liquefied petroleum gases, or naphtha. In industry, heavy pyrolysis resin is most often used as a feedstock for the production of carbon black or as a fuel. The main physical properties of heavy pyrolysis resin are listed in Table 1.

[0033] The technical result is achieved by using stearic or oleic acid as an active additive for defoaming, which belong to the group of unsaturated fatty acids, pre-dispersed in pyrolysis resin and having an affinity for aqueous substrates due to the addition of alcohols and surfactants.

[0034] The technical result is achieved in that the composition contains heavy pyrolysis resin in an amount of 55 - 94 wt.% of the composition and an active additive in an amount of 6 - 45 wt.% of the composition, which ensures the necessary dispersion of the active base in the pyrolysis resin and further in drilling and cementing solutions.

[0035] The technical result is achieved by the fact that the composition can include monohydric alcohols of the aliphatic series, which ensures an increase in the mutual solubility of the components used in drilling and cementing solutions.

[0036] The technical result is achieved by the fact that the composition can include a kerosene-gas oil fraction of straight distillation of petroleum, which provides an additional lubricating effect of the composition.

[0037] The technical result is achieved in that the composition containing heavy pyrolysis resin together with oleic or stearic acid includes one or more of the following components in the specified amount: (i) monohydric alcohols of the aliphatic series in the amount of 5-10 wt.%; (ii) a mixture of polyethylene glycol ethers in the amount of 1-5 wt.%; (iii) a kerosene gas oil fraction of straight distillation of petroleum in the amount of 10-32 wt.%. This composition and proportions of the components ensure effective foam suppression.

[0038] 5

[0039] SUBSTITUTE SHEET (RULE 26) The technical result is achieved by using a hydrocarbon solvent as a component of the foam-fighting composition, which ensures the effective dissolution of oleic acid in it for subsequent introduction into the drilling or cement slurry.

[0040] The technical result is achieved in that the composition containing a hydrocarbon solvent together with oleic acid includes one or more of the following components in the specified amount: (i) monohydric alcohols of the aliphatic series in the amount of 5-15 wt.%; (ii) a mixture of polyethylene glycol ethers in the amount of 1-5 wt.%; (iii) a kerosene-gas oil fraction of straight distillation of petroleum in the amount of 5-20 wt.%, this composition and proportions of the components ensure effective foam suppression.

[0041] The safety and simplicity of the preparation process is one of the advantages of the claimed compositions, since their production requires only simple mixing of the components and does not require the use of special equipment.

[0042] The technical result is achieved by introducing the composition according to the present invention into a drilling or cementing solution, which ensures the suppression of foam in the solution or the prevention of its formation.

[0043] The technical result is achieved in that the composition according to the present invention is introduced into the drilling or cementing solution in an amount of 0.01 to 2% of the mass of the drilling or cementing solution, which ensures effective foam suppression and prevention of its formation, without causing an overconsumption of the composition.

[0044] The technical result is achieved by introducing the components of the described composition into the drilling or cementing solution separately or together, which ensures the suppression of foam in the solution or the prevention of its formation.

[0045] The achievement of the technical result is confirmed by the conducted studies, described in the examples below. For the studies, a model drilling mud, a model cement slurry, and a composition based on industrial water and sodium lignosulfonate foaming agent at a concentration of 5% were prepared.

[0046] Composition of the model drilling mud:

[0047] 6

[0048] SUBSTITUTE SHEET (RULE 26) - soda ash - 2 kg / m3 3 ;

[0049] - caustic soda - 1.5 kg / m3 3 ;

[0050] - sodium chloride - 250 kg / m3 3 ;

[0051] - modified starch - 20 kg / m3 3 ;

[0052] - polyanionic cellulose - 2 kg / m 3 ;

[0053] - biopolymer - 4 kg / m 3 .

[0054] Composition of the model cement slurry:

[0055] PTST-IG-CC-l GOST 1581-2019 - 800 g;

[0056] Filtration reducer - 0.4 g;

[0057] Water - 360 ml.

[0058] The defoaming efficiency was analyzed using the following method. The initial solutions were stirred for 20 minutes, then covered with a lid and left for 24 hours (to stabilize the parameters). After this time, the initial density of the solutions (pi) was measured without stirring according to RD 39-00147001-773-2004.

[0059] 3.1.2. The solutions were then foamed using a mixer. 400 ml of the solution were placed under the mixer and mixed at high speed for 20 minutes. After mixing, 300-350 ml of the solution were poured off, and the density of the lower portion (rg) was measured according to RD 39-00147001-773-2004, paragraph.

[0060] 3.1.2. The remaining solutions were mixed under a stirrer at a speed of 1000-1500 rpm for 30 minutes. After mixing, 0.34 ml of defoamer was added to the solutions. The solutions with defoamer were placed in a mixer and mixed at high speed for 20 minutes. After mixing, 300-350 ml of the solution was drained and the density of the lower part (pz) was measured in accordance with RD 39-00147001-773-2004, clause 3.1.2. The defoaming efficiency coefficient was determined by the formula:

[0061] Based on the research results, it was established that the obtained compositions provide the stated technical result.

[0062] List of tables.

[0063] Table No. 1 - Basic physical properties of heavy pyrolysis resin.

[0064] 7

[0065] SUBSTITUTE SHEET (RULE 26) Example 1.

[0066] Heavy pyrolysis resin in the amount of 94 wt.% and oleic acid in the amount of 7 wt.% were loaded into a process tank equipped with a mixer, then the mass was stirred for 30 minutes at normal temperature and the composition was unloaded.

[0067] We conducted 3 experiments:

[0068] 1. The resulting composition was added to a model cement slurry at a concentration of 1% of the slurry's mass, and foaming was initiated using a stirrer. The foam suppression efficiency was 82%.

[0069] 2. The resulting composition was added to a model drilling fluid at a concentration of 1% by weight, and foaming was initiated in a similar manner. The foam suppression efficiency was 83%.

[0070] 3. The resulting composition was added to a composition based on process water and sodium lignosulfonate foaming agent (concentration 5%) at a rate of 1% of the solution weight, and foaming was initiated. The defoaming efficiency was 82%.

[0071] Example 2.

[0072] The process was carried out in a similar manner to the process described in Example 1, with the difference that the composition contained heavy pyrolysis resin in an amount of 55 wt.% and oleic acid in an amount of 45 wt.%, and as a result of the experiments the following results were obtained:

[0073] Experiment 1: the defoaming efficiency was 92%.

[0074] Experiment 2: the defoaming efficiency was 90%.

[0075] Experiment 3: the defoaming efficiency was 92%.

[0076] Example 3.

[0077] The process was carried out in a similar manner to the process described in Example 1, with the difference that instead of oleic acid, the composition contained stearic acid, and as a result of the experiments the following results were obtained:

[0078] Experiment 1: the defoaming efficiency was 77%.

[0079] Experiment 2: The defoaming efficiency was 79%.

[0080] Experiment 3: the defoaming efficiency was 77%.

[0081] Example 4.

[0082] 8

[0083] SUBSTITUTE SHEET (RULE 26) The process was carried out similarly to the process described in Example 2, with the difference that instead of oleic acid, the composition contained stearic acid, and as a result of the experiments the following results were obtained:

[0084] Experiment 1: The defoaming efficiency was 89%.

[0085] Experiment 2: The defoaming efficiency was 85%.

[0086] Experiment 3: the defoaming efficiency was 90%.

[0087] Example 5.

[0088] The process was carried out similarly to the process described in the Example

[0089] 1, with the difference that instead of oleic acid, the composition contained a mixture of oleic and stearic acid (mixed in equal proportions) in an amount of 6 wt.%, and as a result of the experiments, the following results were obtained:

[0090] Experiment 1: the defoaming efficiency was 78%.

[0091] Experiment 2: The defoaming efficiency was 78%.

[0092] Experiment 3: the defoaming efficiency was 75%.

[0093] Example 6.

[0094] The process was carried out similarly to the process described in the Example

[0095] 2, with the difference that instead of oleic acid, the composition contained a mixture of oleic and stearic acid (mixed in equal proportions) in an amount of 45 wt.%, and as a result of the experiments, the following results were obtained:

[0096] Experiment 1: the defoaming efficiency was 92%.

[0097] Experiment 2: the defoaming efficiency was 90%.

[0098] Experiment 3: the defoaming efficiency was 92%.

[0099] Example 7.

[0100] The process was carried out similarly to the process described in Example 5, with the difference that the composition contained heavy pyrolysis resin in an amount of 87 wt.% and additionally contained monohydric alcohols of the aliphatic series in an amount of 7 wt.%, namely isopropyl alcohol. As a result of the experiments, the following results were obtained:

[0101] Experiment 1: the defoaming efficiency was 82%.

[0102] Experiment 2: the defoaming efficiency was 90%.

[0103] Experiment 3: the defoaming efficiency was 78%.

[0104] 9

[0105] SUBSTITUTE SHEET (RULE 26) Example 8.

[0106] The process was carried out similarly to the process described in Example 5, with the difference that the composition contained heavy pyrolysis resin in an amount of 91 wt.% and additionally contained a mixture of polyethylene glycol ethers in an amount of 3 wt.%; as a result of the experiments, the following results were obtained:

[0107] Experiment 1: The defoaming efficiency was 88%.

[0108] Experiment 2: the defoaming efficiency was 92%.

[0109] Experiment 3: The defoaming efficiency was 89%.

[0110] Example 9.

[0111] The process was carried out similarly to the process described in Example 5, with the difference that the composition contained heavy pyrolysis resin in an amount of 73 wt.% and additionally contained a kerosene-gas oil fraction of straight distillation of oil in an amount of 21 wt.%; as a result of the experiments, the following results were obtained:

[0112] Experiment 1: the defoaming efficiency was 66%.

[0113] Experiment 2: The defoaming efficiency was 66%.

[0114] Experiment 3: the defoaming efficiency was 64%.

[0115] Example 10.

[0116] The process was carried out similarly to the process described in the Example

[0117] 5, with the difference that the composition contained heavy pyrolysis resin in the amount of 63 wt.% and additionally contained monohydric alcohols of the aliphatic series in the amount of 7 wt.%, namely isopropyl alcohol, a mixture of polyethylene glycol ethers in the amount of 3 wt.%, the composition also included a kerosene-gas oil fraction of straight distillation of oil in the amount of 21 wt.%, as a result of the experiments the following results were obtained:

[0118] Experiment 1: the defoaming efficiency was 60%.

[0119] Experiment 2: the defoaming efficiency was 63%.

[0120] Experiment 3: the defoaming efficiency was 55%.

[0121] Example 11.

[0122] The process was carried out similarly to the process described in the Example

[0123] 6, with the difference that the composition contained heavy pyrolysis resin in an amount of 24 wt.% and additionally contained monohydric alcohols of the aliphatic series in an amount of 7 wt.%, namely isopropyl alcohol,

[0124] 10

[0125] SUBSTITUTE SHEET (RULE 26) a mixture of polyethylene glycol ethers in an amount of 3 wt.%. The composition also included a kerosene-gas oil fraction of straight-run petroleum in an amount of 21 wt.%. The following results were obtained as a result of the experiments:

[0126] Experiment 1: the defoaming efficiency was 62%.

[0127] Experiment 2: the defoaming efficiency was 63%.

[0128] Experiment 3: the defoaming efficiency was 63%.

[0129] Example 12.

[0130] A hydrocarbon solvent in an amount of 60 wt.% and oleic acid in an amount of 40 wt.% were loaded into a process tank equipped with a stirrer; diesel fuel was used as a hydrocarbon solvent, then the mass was stirred for 30 minutes at normal temperature and the composition was unloaded.

[0131] We carried out 3 experiments similar to the experiments described in Example 1:

[0132] Experiment 1: the defoaming efficiency was 95%.

[0133] Experiment 2: the defoaming efficiency was 93%.

[0134] Experiment 3: the defoaming efficiency was 96%.

[0135] Example 13.

[0136] A hydrocarbon solvent in the amount of 60 wt.% and oleic acid in the amount of 40 wt.% were loaded into a process tank equipped with a stirrer; a gasoline fraction of oil was used as a hydrocarbon solvent, then the mass was stirred for 30 minutes at normal temperature and the composition was unloaded.

[0137] We carried out 3 experiments similar to the experiments described in Example 1:

[0138] Experiment 1: The defoaming efficiency was 89%.

[0139] Experiment 2: the defoaming efficiency was 90%.

[0140] Experiment 3: the defoaming efficiency was 85%.

[0141] Example 14.

[0142] The process was carried out similarly to the process described in Example 12, with the difference that the composition contained a hydrocarbon solvent in an amount of 95 wt.% and oleic acid in an amount of 5 wt.%, as a result of the experiments the following results were obtained:

[0143] Experiment 1: the defoaming efficiency was 82%.

[0144] 11

[0145] SUBSTITUTE SHEET (RULE 26) Experiment 2: the foam suppression efficiency was 80%.

[0146] Experiment 3: the defoaming efficiency was 80%.

[0147] Example 15.

[0148] The process was carried out similarly to the process described in Example 13, with the difference that the composition contained a hydrocarbon solvent in an amount of 95 wt.% and oleic acid in an amount of 5 wt.%, as a result of the experiments the following results were obtained:

[0149] Experiment 1: the defoaming efficiency was 73%.

[0150] Experiment 2: The defoaming efficiency was 74%.

[0151] Experiment 3: the defoaming efficiency was 68%.

[0152] Example 16.

[0153] The process was carried out similarly to the process described in Example 12, with the difference that the composition contained a hydrocarbon solvent in an amount of 53 wt.% and additionally contained monohydric alcohols of the aliphatic series in an amount of 7 wt.%, namely isopropyl alcohol, as a result of the experiments the following results were obtained:

[0154] Experiment 1: the defoaming efficiency was 95%.

[0155] Experiment 2: The defoaming efficiency was 95%.

[0156] Experiment 3: the defoaming efficiency was 98%.

[0157] Example 17.

[0158] The process was carried out similarly to the process described in Example 12, with the difference that the composition contained a hydrocarbon solvent in an amount of 57 wt.% and additionally contained a mixture of polyethylene glycol ethers in an amount of 3 wt.%; as a result of the experiments, the following results were obtained:

[0159] Experiment 1: the defoaming efficiency was 95%.

[0160] Experiment 2: The defoaming efficiency was 96%.

[0161] Experiment 3: the defoaming efficiency was 97%.

[0162] Example 18.

[0163] The process was carried out similarly to the process described in Example 12, with the difference that the composition contained a hydrocarbon solvent in an amount of 48 wt.% and additionally contained kerosene.

[0164] 12

[0165] SUBSTITUTE SHEET (RULE 26) gasoil fraction of straight distillation of oil in the amount of 12% by weight, as a result of experiments the following results were obtained:

[0166] Experiment 1: The defoaming efficiency was 71%.

[0167] Experiment 2: the defoaming efficiency was 75%.

[0168] Experiment 3: the defoaming efficiency was 69%.

[0169] Example 19.

[0170] The process was carried out similarly to the process described in Example 12, with the difference that the composition contained a hydrocarbon solvent in an amount of 38 wt.% and additionally contained monohydric alcohols of the aliphatic series in an amount of 7 wt.%, namely isopropyl alcohol, a mixture of polyethylene glycol ethers in an amount of 3 wt.%, The composition also included a kerosene-gas oil fraction of straight distillation of oil in an amount of 12 wt.%, as a result of the experiments the following results were obtained:

[0171] Experiment 1: The defoaming efficiency was 90%.

[0172] Experiment 2: the defoaming efficiency was 90%.

[0173] Experiment 3: the defoaming efficiency was 88%.

[0174] Example 20

[0175] Three model solutions of 1 liter each with the addition of a 1% defoamer (80 g of heavy pyrolysis resin and 70 g of oleic acid) were loaded into process tanks equipped with a stirrer and stirred for 20 minutes at high stirrer speeds similar to example 1-19.

[0176] After mixing, the absence of foam was observed in three samples. Experience shows that this method both suppresses foam and prevents its formation.

[0177] Example 21

[0178] The process was carried out in a similar manner to the process described in Example 20, with the difference that stearic acid was used instead of oleic acid.

[0179] The results of the experiment correspond to the results given in Example 20.

[0180] Example 22

[0181] 13

[0182] SUBSTITUTE SHEET (RULE 26) The process was carried out similarly to the process described in Example 20, with the difference that instead of oleic acid, a mixture of oleic and stearic acid was used, obtained by mixing them in equal proportions.

[0183] The results of the experiment correspond to the results given in Example 20.

[0184] Example 23

[0185] Three model solutions of 1 liter each with the addition of a 1% defoamer (80 g of hydrocarbon solvent in the form of a gas oil fraction of straight-run petroleum distillation and 70 g of oleic acid) were loaded into process tanks equipped with a stirrer and stirred for 20 minutes at high stirrer speeds similar to Example 1-19.

[0186] After mixing, the drilling fluid was observed to be free of foam. Experience shows that this method both suppresses foam and prevents its formation.

[0187] Example 24

[0188] The process was carried out similarly to the process described in Example 23, with the difference that diesel fuel was used as the hydrocarbon solvent.

[0189] Example 25

[0190] The processes were carried out similarly to the processes described in Examples 20-24, with the difference that the indicated substances were introduced into the solution in the reverse order.

[0191] The results of the experiment correspond to the results given in Example 20.

[0192] Example 26

[0193] The processes were carried out similarly to the processes described in Examples 20-24, with the difference that the indicated substances were introduced into the solution simultaneously.

[0194] The results of the experiment correspond to the results given in Example 20.

[0195] Sources of information used:

[0196] 14

[0197] SUBSTITUTE SHEET (RULE 26) 1. UK Patent GB2543451B. C09K8 / 48. Antifoam compositions and methods for reducing foam in drilling fluids / Mahmudhani Amir, E. Wilson Robert, Bawa Luciana, Rocker Jacob. Claimed 28.02.2012.

[0198] 2. USSR Patent SU1167192A1. C09K 7 / 06. Defoamer for drilling fluids / Morozov O. A. App. 05.10.1983.

[0199] 3. RF patent RU2155202C2. S09K 7 / 02, E21B 33 / 138. Defoamer-antifoaming agent for drilling and cement slurries. Simonenko L.I., Anisimov A.A., Zlotnikov G.P., Polishchuk A.V., Pogorelov E.V., Gukasova N.M., Pyankova I.E. Application 01 / 15 / 1998.

[0200] 4. Russian Federation Patent RU2495901C2. C09K 8 / 035, C09K 8 / 42, C09K 8 / 58, C09K 8 / 60. Antifoam composition and methods for its production and use / Falana O. M., Marshall E., Zamora F. Appl. 16.09.2011.

[0201] Table No. 1

[0202] Basic physical properties of heavy pyrolysis resin

[0203] SUBSTITUTE SHEET (RULE 26)

Claims

CLAUSES OF THE INVENTION 1. A defoaming composition for drilling or cementing mud, containing heavy pyrolysis resin and an active additive, wherein oleic acid, stearic acid or a mixture thereof is used as the active additive.

2. The antifoam composition according to claim 1, characterized in that it contains the specified components in the following ratio by weight %: Heavy pyrolysis resin - 55 - 94 Active additive - 6 - 45.

3. The composition according to claim 2, characterized in that it additionally contains one or more components: monohydric alcohols of the aliphatic series in an amount of 5-10 wt.%; a mixture of polyethylene glycol ethers in an amount of 1-5 wt.%; a kerosene-gas oil fraction of straight distillation of petroleum in an amount of 10-32 wt.%.

4. A defoaming composition for drilling or cementing mud, containing diesel fuel or a gasoline fraction of oil as a hydrocarbon solvent and an active additive in the form of oleic acid.

5. The antifoam composition according to item 4, characterized in that it contains the specified components in the following ratio, wt.%: Hydrocarbon solvent - 60 - 95 Active additive - 5 - 40.

6. The composition according to claim 5, characterized in that it additionally contains one or more components: monohydric alcohols of the aliphatic series in an amount of 5-15 wt.%; a mixture of polyethylene glycol ethers in an amount of 1-5 wt.%; a kerosene-gas oil fraction of straight distillation of petroleum in an amount of 5-20 wt.%. 16 SUBSTITUTE SHEET (RULE 26) 7. A method for reducing foam formation or breaking down foam in a drilling or cement slurry, comprising adding to the drilling or cement slurry a defoaming composition containing a heavy pyrolysis resin and an active additive, wherein oleic acid, stearic acid or a mixture thereof are used as the active additive, or a defoaming composition containing diesel fuel or a gasoline fraction of oil as a hydrocarbon solvent and an active additive in the form of oleic acid.

8. The method according to paragraph 7, characterized in that the composition is introduced in an amount of 0.01 to 2% of the weight of the drilling or cement slurry. 17 SUBSTITUTE SHEET (RULE 26)

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