Emulsifier for high-temperature-resistant oil-based drilling fluid as well as preparation method and application of emulsifier

Abstract

The invention belongs to the field of treating agents for oil field drilling fluids, and particularly relates to an emulsifier for a high-temperature-resistant oil-based drilling fluid as well as a preparation method and application of the emulsifier. The emulsifier for the high-temperature-resistant oil-based drilling fluid, provided by the invention, contains a multi-arm structure compound, and the multi-arm structure compound is a compound with a structure as shown in a formula (I) and / or a formula (II). The emulsifier for the oil-based drilling fluid is of a multi-arm structure, is good in temperature resistance, can remarkably improve the stability of a water-in-oil emulsion under a high-temperature condition, and effectively solves the problem that an existing emulsifier is insufficient in temperature resistance. Besides, the emulsifier for the oil-based drilling fluid provided by the invention can be independently used, does not need to use an auxiliary emulsifier, is simple and convenient in synthesis condition, and has a good industrial prospect. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the field of treating agents for oilfield drilling fluids, and in particular relates to an emulsifier for high temperature resistant oil-based drilling fluids, a preparation method and application thereof. Background Art

[0002] During the drilling process of shale gas horizontal wells, fragile zones and other complex formations, water has a dispersing effect on clay, and the use of conventional water-based drilling fluid systems is prone to clay hydration and dispersion, causing wellbore instability, especially in formations with a high content of shale, which can easily affect downhole construction safety. The continuous phase in oil-based drilling fluid is diesel (or white oil), and clay does not hydrate and disperse in oil-based drilling fluid, which is more conducive to wellbore stability; and compared with water-based drilling fluid, oil-based drilling fluid has good lubricity, low friction, and is conducive to reservoir protection. It has been widely used in drilling in various complex formations. At present, the oil-based drilling fluid used on site is an oil-in-water emulsion system with an oil-water ratio generally between 7:3 and 9:1. In order to ensure the stable performance of the oil-based drilling fluid, an oil-based emulsifier must be used to reduce the oil-water interfacial tension and maintain the stability of the emulsion.

[0003] With the development of drilling technology, the number of deep wells and ultra-deep wells is increasing. Affected by the geothermal gradient, the bottom hole temperature is getting higher and higher, and the bottom hole temperature of some wells has exceeded 200°C. Therefore, for oil-based drilling fluids, ensuring the stability of the emulsion at high temperature is the primary issue in the drilling process of oil-based drilling fluids, and oil-based emulsifiers are the key.

[0004] The Chinese patent with application number 201810900379.X discloses an oil-based emulsifier, which is synthesized from cardanol, epichlorohydrin, dimethylamine and 1,3-propane sultone, and has a temperature resistance of up to 180°C; the Chinese patent with application number 201610704229.2 discloses an emulsifier, which is synthesized from oxidized tall oil fatty acid, diethylenetriamine, tetraethylenepentamine, p-methylpropanesulfonic acid and chlorosulfonic acid, and has good emulsification stability and a temperature resistance of up to 200°C. The oil-based emulsifiers synthesized in the above two schemes are mainly oil-soluble molecules with linear or comb-shaped structures, and have insufficient temperature resistance, making it difficult to meet the requirements of high-temperature formation drilling above 200°C. Summary of the invention

[0005] In view of this, the object of the present invention is to provide an emulsifier for high-temperature resistant oil-based drilling fluid, and a preparation method and application thereof. The emulsifier for oil-based drilling fluid provided by the present invention has a multi-arm structure, has good temperature resistance, can still ensure the stability of oil-in-water emulsion in high-temperature formations above 200°C, and is very suitable for application in high-temperature resistant oil-based drilling fluid systems.

[0006] The present invention provides an emulsifier for high temperature resistant oil-based drilling fluid, wherein the emulsifier for high temperature resistant oil-based drilling fluid contains a multi-arm structure compound, wherein the multi-arm structure compound is a compound of formula (I) and / or formula (II):

[0007]

[0008] In formula (I) and formula (II), each R is independently selected from C 8 ~C 20 A straight chain alkyl or C 8 ~C 20 Each Z is independently selected And at least one Z is At least one Z is m is an integer between 1 and 10.

[0009] Preferably, m is an integer between 2 and 5.

[0010] Preferably, the R independently selects C 11 ~C 18 A straight chain alkyl or C 11 ~C 18 Containing benzene ring alkyl.

[0011] Preferably, the high temperature resistant oil-based drilling fluid emulsifier further contains a diluent; the added amount of the diluent is 20 to 30% of the mass of the multi-arm structure compound.

[0012] The present invention provides a method for preparing the high temperature resistant oil-based drilling fluid emulsifier described in the above technical solution, comprising the following steps:

[0013] a) Compound A is mixed with a polyamine of formula (i) to obtain an intermediate;

[0014] The compound A is a benzene ring-containing polyacid and / or a benzene ring-containing polyacid anhydride, the benzene ring-containing polyacid is trimesic acid and / or pyromellitic acid, and the benzene ring-containing polyacid anhydride is pyromellitic anhydride;

[0015]

[0016] In formula (i), m is an integer between 1 and 10;

[0017] b) the intermediate is mixed with a long-chain fatty acid of formula (ii) for reaction, and then mixed with a long-chain alkyl sulfonic acid of formula (iii) for further reaction to obtain an emulsifier for high temperature resistant oil-based drilling fluid;

[0018] R-COOH formula (ii); R-SO 3 H-formula (iii);

[0019] In formula (ii) and formula (iii), R is independently selected from C 8 ~C 20 Straight chain alkyl or C 8 ~C 20 Containing benzene ring alkyl.

[0020] Preferably, the polyamine is triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine or hexaethyleneheptamine;

[0021] The long-chain fatty acid is lauric acid, myristic acid, hexadecanoic acid, oleic acid or stearic acid;

[0022] The long-chain alkyl sulfonic acid is dodecylbenzene sulfonic acid.

[0023] Preferably, the molar ratio of the compound A, the polyamine, the long-chain fatty acid and the long-chain alkyl sulfonic acid is 1:(3-4.1):(8-22):(3-7).

[0024] Preferably, in step a), the temperature of the mixed reaction is 100-120° C., and the time of the mixed reaction is 0.5-1 h;

[0025] In step b), the temperature of the mixed reaction is 150-180° C., and the time of the mixed reaction is 1-3 hours; the temperature of the continued reaction is 150-180° C., and the time of the continued reaction is 0.5-1 hour.

[0026] Preferably, the preparation method further comprises: adding a diluent to the obtained reaction product after completing the continued reaction of step b).

[0027] The present invention provides an oil-based drilling fluid, wherein the oil-based drilling fluid contains the high-temperature resistant oil-based drilling fluid emulsifier described in the above technical solution or the high-temperature resistant oil-based drilling fluid emulsifier prepared by the preparation method described in the above technical solution.

[0028] Compared with the prior art, the present invention provides an emulsifier for high temperature resistant oil-based drilling fluid and a preparation method and application thereof. The emulsifier for high temperature resistant oil-based drilling fluid provided by the present invention contains a multi-arm structure compound, wherein the multi-arm structure compound is a compound of formula (I) and / or formula (II); in formula (I) and formula (II), each R independently selects C 8 ~C 20 Straight chain alkyl or C 8 ~C 20 Each Z is independently selected And at least one Z is At least one Z is m is an integer between 1 and 10. The oil-based drilling fluid emulsifier provided by the present invention has a multi-arm structure and good temperature resistance, which can significantly improve the stability of the water-in-oil emulsion under high temperature conditions, and effectively solve the problem of insufficient temperature resistance of the existing emulsifier. In addition, the oil-based drilling fluid emulsifier provided by the present invention can be used alone without the use of an auxiliary emulsifier, and the synthesis conditions of the emulsifier are simple, and it has good industrial prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0030] Figure 1 The synthetic route diagram of the compound of formula (I) provided in the embodiment of the present invention is to use pyromellitic acid or pyromellitic anhydride as the starting reactant;

[0031] Figure 2 The synthetic route diagram of the compound of formula (II) using trimesic acid as the starting reactant provided in the embodiment of the present invention is shown. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The present invention provides an emulsifier for high temperature resistant oil-based drilling fluid, wherein the emulsifier for high temperature resistant oil-based drilling fluid contains a multi-arm structure compound, wherein the multi-arm structure compound is a compound of formula (I) and / or formula (II):

[0034]

[0035]

[0036] In formula (I) and formula (II), each R is independently selected from C 8 ~C 20 A straight chain alkyl or C 8 ~C 20 Each Z is independently selected And at least one of all Z is At least one Z is m is an integer between 1 and 10.

[0037] In the high temperature resistant oil-based drilling fluid emulsifier provided by the present invention, in the compounds of formula (I) and formula (II), when each R is independently selected from C 8 ~C 20 When the straight chain alkyl group is C 8 Straight chain alkyl, C 9 Straight chain alkyl, C 10 Straight chain alkyl, C 11 Straight chain alkyl, C 12 Straight chain alkyl, C 13 Straight chain alkyl, C 14 Straight chain alkyl, C 15 Straight chain alkyl, C 16 Straight chain alkyl, C 17 Straight chain alkyl, C 18 Straight chain alkyl, C 19 Straight chain alkyl or C 20 Straight chain alkyl, preferably C 11 ~C 18 of a straight chain alkyl group.

[0038] In the high temperature resistant oil-based drilling fluid emulsifier provided by the present invention, in the compounds of formula (I) and formula (II), when each R is independently selected from C 8 ~C 20 When the phenyl ring alkyl group is present, it may be C 8 Containing benzene ring alkyl, C 9 Containing benzene ring alkyl, C 10 Containing benzene ring alkyl, C 11 Containing benzene ring alkyl, C 12 Containing benzene ring alkyl, C 13 Containing benzene ring alkyl, C 14 Containing benzene ring alkyl, C 15 Containing benzene ring alkyl, C 16 Containing benzene ring alkyl, C 17 Containing benzene ring alkyl, C 18 Containing benzene ring alkyl, C 19 Containing benzene ring alkyl or C 20 Contains a benzene ring alkyl group, preferably C 11 ~C 18 Containing benzene ring alkyl.

[0039] In the high temperature resistant oil-based drilling fluid emulsifier provided by the present invention, in the structural compounds of formula (I) and formula (II), m can be specifically 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, preferably an integer between 2 and 5.

[0040] In the high temperature resistant oil-based drilling fluid emulsifier provided by the present invention, in order to facilitate the addition and use of the emulsifier in the drilling fluid, the high temperature resistant oil-based drilling fluid emulsifier preferably also contains a diluent, and the diluent includes but is not limited to white oil; the added amount of the diluent is preferably 20-30% of the mass of the multi-arm structure compound, specifically 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% or 30%.

[0041] The oil-based drilling fluid emulsifier provided by the present invention has a multi-arm structure and good temperature resistance, and can significantly improve the stability of water-in-oil emulsions under high temperature conditions, effectively solving the problem of insufficient temperature resistance of existing emulsifiers. In addition, the oil-based drilling fluid emulsifier can be used alone without the use of an auxiliary emulsifier.

[0042] The present invention also provides a method for preparing the high temperature resistant oil-based drilling fluid emulsifier described in the above technical solution, comprising the following steps:

[0043] a) Compound A is mixed with a polyamine of formula (i) to obtain an intermediate;

[0044] The compound A is a benzene ring-containing polyacid and / or a benzene ring-containing polyacid anhydride, the benzene ring-containing polyacid is trimesic acid and / or pyromellitic acid, and the benzene ring-containing polyacid anhydride is pyromellitic anhydride;

[0045]

[0046] In formula (i), m is an integer between 1 and 10;

[0047] b) the intermediate is mixed with a long-chain fatty acid of formula (ii) for reaction, and then mixed with a long-chain alkyl sulfonic acid of formula (iii) for further reaction to obtain an emulsifier for high temperature resistant oil-based drilling fluid;

[0048] R-COOH formula (ii); R-SO 3 H-formula (iii);

[0049] In formula (ii) and formula (iii), R independently selects C 8 ~C 20 Straight chain alkyl or C 8 ~C 20 Containing benzene ring alkyl.

[0050] In the preparation method provided by the present invention, the synthesis route of the high temperature resistant oil-based drilling fluid emulsifier is as follows: Figures 1-2 As shown, Figure 1 The synthetic route diagram of the compound of formula (I) is provided in the embodiment of the present invention using pyromellitic acid or pyromellitic anhydride as the starting reactant. Figure 2The synthetic route diagram of the compound of formula (II) using trimesic acid as the starting reactant provided in the embodiment of the present invention is shown.

[0051] In the preparation method provided by the present invention, in step a), in the polyamine of formula (i), m can be 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, preferably an integer between 2 and 5. In the present invention, when m is an integer between 2 and 5, the corresponding polyamine is specifically triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine or hexaethyleneheptamine.

[0052] In the preparation method provided by the present invention, in step a), the molar ratio of compound A to polyamine is preferably 1:(3-4.1), specifically 1:3, 1:3.05, 1:3.1, 1:3.15, 1:3.2, 1:3.25, 1:3.3, 1:3.35, 1:3.4, 1:3.45, 1:3.5, 1:3.55, 1:3.6, 1:3.65, 1:3.7, 1:3.75, 1:3.8, 1:3.85, 1:3.9, 1:3.95, 1:4, 1:4.05 or 1:4.1.

[0053] In the preparation method provided by the present invention, in step a), the temperature of the mixed reaction is preferably 100-120°C, specifically 100°C, 102°C, 105°C, 107°C, 110°C, 112°C, 115°C, 117°C or 120°C; the time of the mixed reaction is preferably 0.5-1h, specifically 0.5h, 0.55h, 0.6h, 0.65h, 0.7h, 0.75h, 0.8h, 0.85h, 0.9h, 0.95h or 1h.

[0054] In the preparation method provided by the present invention, in step a), the specific process of the mixed reaction is preferably: first, compound A is added to the reactor, deoxygenated, then polyamine is added under stirring conditions, and then the temperature is raised to the reaction temperature for reaction. The deoxygenation method is preferably nitrogen deoxygenation, and the nitrogen deoxygenation time is preferably 10 to 30 minutes; the reaction temperature corresponds to the temperature of the mixed reaction described above; the reaction time after the temperature is raised to the reaction temperature corresponds to the time of the mixed reaction described above.

[0055] In the preparation method provided by the present invention, in step b), in the long-chain fatty acid of formula (ii), when R is selected from C 8 ~C 20 When the straight chain alkyl group is C 8 Straight chain alkyl, C 9 Straight chain alkyl, C 10 Straight chain alkyl, C 11 Straight chain alkyl, C12 Straight chain alkyl, C 13 Straight chain alkyl, C 14 Straight chain alkyl, C 15 Straight chain alkyl, C 16 Straight chain alkyl, C 17 Straight chain alkyl, C 18 Straight chain alkyl, C 19 Straight chain alkyl or C 20 Straight chain alkyl, preferably C 11 ~C 18 When R is selected from C 8 ~C 20 When the phenyl ring alkyl group is present, it may be C 8 Containing benzene ring alkyl, C 9 Containing benzene ring alkyl, C 10 Containing benzene ring alkyl, C 11 Containing benzene ring alkyl, C 12 Containing benzene ring alkyl, C 13 Containing benzene ring alkyl, C 14 Containing benzene ring alkyl, C 15 Containing benzene ring alkyl, C 16 Containing benzene ring alkyl, C 17 Containing benzene ring alkyl, C 18 Containing benzene ring alkyl, C 19 Containing benzene ring alkyl or C 20 Contains a benzene ring alkyl group, preferably C 11 ~C 18 Containing benzene ring alkyl.

[0056] In the preparation method provided by the present invention, in step b), the long-chain fatty acid can more specifically be lauric acid, myristic acid, hexadecanoic acid, oleic acid or stearic acid.

[0057] In the preparation method provided by the present invention, in step b), the molar ratio of the long-chain fatty acid to the preparation raw material compound A of the intermediate is preferably (8-22):1, specifically 8:1, 8.5:1, 9:1, 9.5:1, 10:1, 10.5:1, 11:1, 11.5:1, 12:1, 12.5:1, 13:1, 13.5:1, 14:1, 14.5:1, 15:1, 15.5:1, 16:1, 16.5:1, 17:1, 17.5:1, 18:1, 18.5:1, 19:1, 19.5:1, 20:1, 20.5:1, 21:1, 21.5:1 or 22:1.

[0058] In the preparation method provided by the present invention, in step b), the temperature of the mixed reaction is preferably 150-180°C, specifically 150°C, 152°C, 155°C, 157°C, 160°C, 162°C, 165°C, 167°C, 170°C, 172°C, 175°C, 178°C or 180°C; the time of the mixed reaction is preferably 1-3h, specifically 1h, 1.2h, 1.5h, 1.7h, 2h, 2.3h, 2.5h, 2.7h or 3h.

[0059] In the preparation method provided by the present invention, in step b), in the long-chain alkyl sulfonic acid of formula (iii), when R is selected from C 8 ~C 20 When the straight chain alkyl group is C 8 Straight chain alkyl, C 9 Straight chain alkyl, C 10 Straight chain alkyl, C 11 Straight chain alkyl, C 12 Straight chain alkyl, C 13 Straight chain alkyl, C 14 Straight chain alkyl, C 15 Straight chain alkyl, C 16 Straight chain alkyl, C 17 Straight chain alkyl, C 18 Straight chain alkyl, C 19 Straight chain alkyl or C 20 Straight chain alkyl, preferably C 11 ~C 18 When R is selected from C 8 ~C 20 When the phenyl ring alkyl group is present, it may be C 8 Containing benzene ring alkyl, C 9 Containing benzene ring alkyl, C 10 Containing benzene ring alkyl, C 11 Containing benzene ring alkyl, C 12 Containing benzene ring alkyl, C 13 Containing benzene ring alkyl, C 14 Containing benzene ring alkyl, C 15 Containing benzene ring alkyl, C 16 Containing benzene ring alkyl, C 17 Containing benzene ring alkyl, C 18 Containing benzene ring alkyl, C 19 Containing benzene ring alkyl or C 20 Contains a benzene ring alkyl group, preferably C 11 ~C 18 Containing benzene ring alkyl.

[0060] In the preparation method provided by the present invention, in step b), the long-chain alkyl sulfonic acid can more specifically be dodecylbenzenesulfonic acid.

[0061] In the preparation method provided by the present invention, in step b), the molar ratio of the long-chain alkyl sulfonic acid to the preparation raw material compound A of the intermediate is preferably (3-7):1, specifically 3:1, 3.2:1, 3.5:1, 3.7:1, 4:1, 4.2:1, 4.5:1, 4.7:1, 5:1, 5.2:1, 5.5:1, 5.7:1, 6:1, 6.2:1, 6.5:1, 6.7:1 or 7:1.

[0062] In the preparation method provided by the present invention, in step b), the temperature of the continued reaction is preferably 150-180°C, specifically 150°C, 152°C, 155°C, 157°C, 160°C, 162°C, 165°C, 167°C, 170°C, 172°C, 175°C, 178°C or 180°C; the time of the continued reaction is preferably 0.5-1h, specifically 0.5h, 0.55h, 0.6h, 0.65h, 0.7h, 0.75h, 0.8h, 0.85h, 0.9h, 0.95h or 1h.

[0063] In the preparation method provided by the present invention, in step b), the specific process of the mixed reaction and the continued reaction is preferably: adding a long-chain fatty acid to the intermediate prepared in step a), then heating to the reaction temperature for reaction, and adding a long-chain alkyl sulfonic acid after a period of reaction to continue the reaction. Wherein, the reaction temperature corresponds to the temperature of the mixed reaction described above; the time for the reaction after heating to the reaction temperature corresponds to the time for the mixed reaction described above; the temperature for the continued reaction corresponds to the temperature for the continued reaction described above; and the time for the continued reaction corresponds to the time for the continued reaction described above.

[0064] In the preparation method provided by the present invention, it is preferred to further include the following steps: after completing the continued reaction of step b), adding a diluent to the obtained reaction product. Wherein, the diluent includes but is not limited to white oil; the amount of the diluent added is preferably 20-30% of the total mass of compound A, polyamine of formula (i), long-chain fatty acid of formula (ii) and long-chain alkyl sulfonic acid of formula (iii), specifically 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% or 30%; before adding the diluent, the reaction product is preferably cooled to 80-100°C, specifically 80°C, 82°C, 85°C, 87°C, 90°C, 92°C, 95°C, 97°C or 100°C.

[0065] The preparation method of the high temperature resistant oil-based drilling fluid emulsifier provided by the invention has simple process, easily controllable conditions and good industrialization prospect.

[0066] The present invention also provides an oil-based drilling fluid, comprising an oil base and an emulsifier; wherein the oil base includes but is not limited to diesel; the emulsifier is the emulsifier for oil-based drilling fluid described in the above technical scheme or the emulsifier for oil-based drilling fluid prepared by the preparation method described in the above technical scheme; the mass volume ratio of the emulsifier to the oil base is preferably (8-20) g:240 mL, specifically 8 g:240 mL, 9 g:240 mL, 10 g:240 mL, 11 g:240 mL, 12 g:240 mL, 13 g:240 mL, 14 g:240 mL, 15 g:240 mL, 16 g:240 mL, 17 g:240 mL, 18 g:240 mL, 19 g:240 mL or 20 g:240 mL.

[0067] The oil-based drilling fluid provided by the present invention also contains other functional components, including but not limited to one or more of calcium chloride, organic soil for oil-based drilling fluid, oil-based shear enhancer, oxidized asphalt, humic acid amide fluid loss reducer, calcium oxide and barite.

[0068] For the purpose of greater clarity, the present invention is described in detail with reference to the following examples and comparative examples.

[0069] Example 1

[0070] 1 mol of trimesic acid is added to a reaction container, nitrogen is passed through for 30 minutes to deoxygenate, and then 3 mol of tetraethylenepentamine is added under stirring conditions, the temperature is raised to 100° C. and the reaction is carried out for 0.8 hours, and then 10 mol of dodecanoic acid is added to the reaction container, the system is heated to 160° C. and the reaction is carried out for 3 hours, and then 4.5 mol of dodecylbenzenesulfonic acid is added to the reaction container and the reaction is continued for 0.5 hours, and the temperature is lowered to 100° C., and 25% of the total mass of the above raw materials white oil is added to the reaction container, and the temperature is lowered to room temperature to obtain a high temperature resistant oil-based drilling fluid emulsifier containing a compound of formula (II).

[0071] Example 2

[0072] 1 mol of pyromellitic acid is added to a reaction container, nitrogen is passed through for 10 minutes for deoxygenation, and then 4.1 mol of triethylenetetramine is added under stirring conditions, the temperature is raised to 120°C and the reaction is carried out for 0.5 hours, and then 11 mol of oleic acid is added to the reaction container, the system is heated to 150°C and the reaction is carried out for 2 hours, and then 4 mol of dodecylbenzenesulfonic acid is added to the reaction container and the reaction is continued for 0.6 hours, and the temperature is lowered to 80°C, and 20% of the total mass of white oil of the above raw materials is added to the reaction container, and the temperature is cooled to room temperature to obtain an emulsifier for high temperature resistant oil-based drilling fluid containing a compound of formula (I).

[0073] Example 3

[0074] 1 mol of pyromellitic anhydride is added to a reaction container, nitrogen is passed through for 15 minutes for deoxygenation, and then 4 mol of hexaethyleneheptamine is added under stirring conditions, the temperature is raised to 115° C. for reaction for 1 hour, and then 22 mol of hexadecanoic acid is added to the reaction container, the system is heated to 180° C. for reaction for 1 hour, and then 7 mol of dodecylbenzenesulfonic acid is added to the reaction container and the reaction is continued for 1 hour, the temperature is lowered to 90° C., 30% of the total mass of white oil of the above raw materials is added to the reaction container, and the temperature is cooled to room temperature to obtain a high temperature resistant oil-based drilling fluid emulsifier containing a compound of formula (I).

[0075] Embodiments 4 to 6

[0076] The steps are the same as those in Example 1, and the reaction substances and their amounts are shown in Table 1:

[0077] Table 1 Reaction substances and dosage

[0078] Example Polyacid (or anhydride) Polyamine Long-chain fatty acids Long chain alkyl sulfonic acid 4 1 mol trimesic acid 3.05 mol triethylenetetramine 8mol tetradecanoic acid 3 mol dodecylbenzenesulfonic acid 5 1 mol pyromellitic anhydride 4.05 mol pentaethylenehexamine 17mol stearic acid 6.5mol dodecylbenzenesulfonic acid 6 1 mol pyromellitic acid 4.1 mol tetraethylenepentamine 13.5mol oleic acid 6mol dodecylbenzenesulfonic acid

[0079] Comparative Example 1

[0080] 1 mol of hexaethyleneheptamine was added to a reaction container, nitrogen was passed for 15 minutes to deoxygenate, and then 5.5 mol of oleic acid was added under stirring conditions. The system was heated to 150°C for reaction for 3 hours, and then 2.2 mol of dodecylbenzenesulfonic acid was added to the reaction container and the reaction was continued for 0.6 hours. The temperature was lowered to 80°C, and 20% of the total mass of white oil of the above raw materials was added to the reaction container. The temperature was cooled to room temperature to obtain an oil-based emulsifier with a comb-type structure.

[0081] Performance Evaluation

[0082] The performance of the oil-based drilling fluid emulsifiers synthesized in Examples 1 to 6 and Comparative Example 1 was evaluated, and the specific evaluation contents are as follows:

[0083] (1) Emulsification rate

[0084] 240mL of 0# diesel and 12g of sample (the emulsifier for oil-based drilling fluid prepared in Examples 1 to 6 and Comparative Example 1) were added to a high-stirring cup, stirred at 10000r for 20min, and then 60mL of distilled water and 9.0g of calcium oxide were added, and stirred at high speed for 30min. The prepared emulsion was put into a high-temperature aging tank, placed in a high-temperature roller heating furnace, rolled at 230°C for 16h, taken out and cooled, stirred at high speed for 20min, poured into a 500mL measuring cylinder, and left to stand at room temperature for 24h, and the volume V of the clear oil separated from the upper layer was observed; the emulsification rate was calculated as follows:

[0085]

[0086] Wherein, W is emulsification rate, %; V is the volume of the oil layer separated in 24 hours, in milliliters (mL).

[0087] The calculation results are shown in Table 2:

[0088] Table 2 Emulsification rate of high temperature resistant emulsifier

[0089] project Emulsification rate, % Example 1 96 Example 2 97 Example 3 98 Example 4 96 Example 5 98 Example 6 97 Comparative Example 1 84.3

[0090] (2) Temperature resistance

[0091] 240mL of 0# diesel was added to a high-stirring cup, and then 15g of the oil-based drilling fluid emulsifier samples prepared in Examples 1 to 6 and Comparative Example 1 were added under high-speed stirring (stirring speed 11000r / min, the same below), and stirred at high speed for 10min; then 60mL of calcium chloride aqueous solution (mass concentration 25%) was added, and stirred at high speed for 20min; then 12.0g of organic soil for oil-based drilling fluid was added, and stirred at high speed for 5min; then 3.0g of oil-based shearing agent LVSP (produced by the Drilling Engineering Technology Research Institute of Sinopec Zhongyuan Petroleum Engineering Co., Ltd.) was added, and stirred at high speed for 5min; then 12.0g of oxidized asphalt and 9g of humic acid amide filtrate reducer were added, and stirred at high speed for 5min; then 9.0g of calcium oxide was added, and stirred at high speed for 5min; then the density of the drilling fluid was increased to 1.6g / cm with barite. 3 , high-speed stirring for 20 minutes, put into the aging tank and roll aging at 230℃ for 16 hours, and investigate the comprehensive performance of the oil-based drilling fluid after high-temperature aging. The results are shown in Table 3:

[0092] Table 3 Performance evaluation of high temperature resistant oil-based emulsifier

[0093]

[0094]

[0095] It can be seen from the above evaluation results that the synthesized high temperature resistant oil-based drilling fluid emulsifier of the present invention has good emulsification performance, does not require the use of auxiliary emulsifiers, and has a temperature resistance of up to 230°C, and can be used in high temperature resistant oil-based drilling fluid systems.

[0096] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An emulsifier for high temperature resistant oil-based drilling fluid, It is characterized in that The high temperature resistant oil-based drilling fluid emulsifier contains a multi-arm structure compound, and the multi-arm structure compound is a compound of formula (I) and / or formula (II): In formula (I) and formula (II), each R is independently selected from C 8 ~C 20 A straight chain alkyl or C 8 ~C 20 Each Z is independently selected And at least one Z is At least one Z is m is an integer between 1 and 10.

2. The high temperature resistant oil-based drilling fluid emulsifier according to claim 1, It is characterized in that The m is an integer between 2 and 5.

3. The high temperature resistant oil-based drilling fluid emulsifier according to claim 1, It is characterized in that The R independently selects C 11 ~C 18 Straight chain alkyl or C 11 ~C 18 Containing benzene ring alkyl.

4. The high temperature resistant oil-based drilling fluid emulsifier according to claim 1, It is characterized in that The high temperature resistant oil-based drilling fluid emulsifier also contains a diluent; the added amount of the diluent is 20-30% of the mass of the multi-arm structure compound.

5. A method for preparing the high temperature resistant oil-based drilling fluid emulsifier according to any one of claims 1 to 4, It is characterized in that The following steps are involved: a) Compound A is mixed with a polyamine of formula (i) to obtain an intermediate; The compound A is a benzene ring-containing polyacid and / or a benzene ring-containing polyacid anhydride, the benzene ring-containing polyacid is trimesic acid and / or pyromellitic acid, and the benzene ring-containing polyacid anhydride is pyromellitic anhydride; In formula (i), m is an integer between 1 and 10; b) the intermediate is mixed with a long-chain fatty acid of formula (ii) for reaction, and then mixed with a long-chain alkyl sulfonic acid of formula (iii) for further reaction to obtain an emulsifier for high temperature resistant oil-based drilling fluid; R-COOH formula (ii); R-SO 3 H-formula (iii); In formula (ii) and formula (iii), R is independently selected from C 8 ~C 20 Straight chain alkyl or C 8 ~C 20 Containing benzene ring alkyl.

6. The preparation method according to claim 5, It is characterized in that The polyamine is triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine or hexaethyleneheptamine; The long-chain fatty acid is lauric acid, myristic acid, hexadecanoic acid, oleic acid or stearic acid; The long-chain alkyl sulfonic acid is dodecylbenzene sulfonic acid.

7. The preparation method according to claim 5, It is characterized in that The molar ratio of the compound A, polyamine, long-chain fatty acid and long-chain alkyl sulfonic acid is 1:(3-4.1):(8-22):(3-7).

8. The preparation method according to claim 5, It is characterized in that In step a), the temperature of the mixed reaction is 100-120° C., and the time of the mixed reaction is 0.5-1 h; In step b), the temperature of the mixed reaction is 150-180° C., and the time of the mixed reaction is 1-3 hours; the temperature of the continued reaction is 150-180° C., and the time of the continued reaction is 0.5-1 hour.

9. The preparation method according to claim 5, It is characterized in that Also includes: After the continued reaction of step b) is completed, a diluent is added to the obtained reaction product.

10. An oil-based drilling fluid, It is characterized in that The oil-based drilling fluid contains the high-temperature resistant oil-based drilling fluid emulsifier according to any one of claims 1 to 4 or the high-temperature resistant oil-based drilling fluid emulsifier prepared by the preparation method according to any one of claims 5 to 9.

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