Emulsifier for 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 an oil-based drilling fluid as well as a preparation method and application of the emulsifier. The emulsifier for the oil-based drilling fluid, provided by the invention, contains a compound with a structure as shown in a formula (I), in the formula (I), R1 is C8-C20 straight-chain alkyl, R2 is C8-C20 straight-chain alkyl or C8-C20 benzene-containing naphthenic base, Z is # imgabs0, and X is-H or-OH. The emulsifier provided by the invention has a multi-arm structure, compared with a conventional emulsifier with a linear structure, the emulsifying and temperature-resistant properties are better, the stability of a water-in-oil emulsion under a high-temperature condition can be remarkably improved, and the problem that the temperature-resistant property of an existing emulsifier is insufficient is effectively solved. The emulsifier 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. # imgabs1 #

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 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] At present, there are many domestic studies on oil-based emulsifiers: Chinese patent 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; Chinese patent application number 201310237577.X discloses an oil-based emulsifier, which is obtained by polycondensation reaction using long-chain fatty acid methyl ester, hydroxyethyl diamine and propylene oxide as raw materials. The oil-based emulsifiers synthesized in the above two schemes are mainly oil-soluble molecules with linear structures, which have insufficient temperature resistance and are difficult to meet the needs of high-temperature formation drilling. Summary of the invention

[0004] In view of this, the object of the present invention is to provide an emulsifier for oil-based drilling fluid and a preparation method and application thereof. The emulsifier provided by the present invention has a multi-arm structure, has excellent emulsification and temperature resistance, can meet the stability requirements of high-temperature formation oil-in-water emulsions, and is very suitable for application in high-temperature resistant oil-based drilling fluid systems.

[0005] The present invention provides an emulsifier for oil-based drilling fluid, wherein the emulsifier for oil-based drilling fluid contains a compound of formula (I):

[0006]

[0007] In formula (I), R 1 C 8 ~C 20 The straight chain alkyl group, R 2 C 8 ~C 20 A straight chain alkyl or C8 ~C 20 containing a benzene ring alkyl group, Z is X is -H or -OH.

[0008] Preferably, the R 1 C 12 ~C 18 of a straight chain alkyl group.

[0009] Preferably, the R 2 C 11 ~C 18 A straight chain alkyl or C 11 ~C 18 Containing benzene ring alkyl.

[0010] Preferably, the oil-based drilling fluid emulsifier further contains a diluent; the added amount of the diluent is 20-30% of the mass of the compound of the formula (I).

[0011] The present invention provides a method for preparing an emulsifier for oil-based drilling fluid according to the above technical solution, comprising the following steps:

[0012] a) reacting a polyacid of formula (i) with a long-chain polyamine of formula (ii) to obtain an intermediate;

[0013] b) mixing the intermediate with a long-chain alkyl acid of formula (iii) to obtain an emulsifier for oil-based drilling fluid;

[0014]

[0015] H 2 N-CH 2 -CH 2 -CH 2 -NH-R 1 Formula (ii);

[0016] HO-ZR 2 Formula (iii);

[0017] In formulas (i) to (iii), R 1 C 5 ~C 20 The straight chain alkyl group, R 2 C 5 ~C 20 A straight chain alkyl or C 5 ~C 20 containing a benzene ring alkyl group, Z is X is -H or -OH.

[0018] Preferably, the long-chain polyamine is N-dodecyl-1,3-propylenediamine, N-tetradecyl-1,3-propylenediamine, N-hexadecyl-1,3-propylenediamine, N-oleyl-1,3-propylenediamine or N-octadecyl-1,3-propylenediamine;

[0019] The long-chain alkyl acid is lauric acid, myristic acid, hexadecanoic acid, oleic acid, stearic acid or dodecylbenzenesulfonic acid.

[0020] Preferably, the molar ratio of the polyacid, the long-chain polyamine and the long-chain alkyl acid is 1:(3-3.1):(3-5).

[0021] Preferably, in step a), the temperature of the mixed reaction is 120-140° C., and the time of the mixed reaction is 1-3 h;

[0022] In step b), the temperature of the mixed reaction is 150-180° C., and the time of the mixed reaction is 1-3 hours.

[0023] Preferably, the preparation method further comprises: adding a diluent to the obtained reaction product after completing the mixing reaction in step b).

[0024] The present invention provides an oil-based drilling fluid, wherein the oil-based drilling fluid contains the oil-based drilling fluid emulsifier described in the above technical solution or the oil-based drilling fluid emulsifier prepared by the preparation method described in the above technical solution.

[0025] Compared with the prior art, the present invention provides an emulsifier for oil-based drilling fluid and a preparation method and application thereof. The emulsifier for oil-based drilling fluid provided by the present invention contains a compound of formula (I), wherein R 1 C 8 ~C 20 The straight chain alkyl group, R 2 C 8 ~C 20 A straight chain alkyl or C 8 ~C 20 containing a benzene ring alkyl group, Z is X is -H or -OH. The emulsifier provided by the present invention has a multi-arm structure, and compared with the conventional linear emulsifier, it has better emulsification and temperature resistance, can significantly improve the stability of the oil-in-water emulsion under high temperature conditions, and effectively solve the problem of insufficient temperature resistance of the existing emulsifier. The 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

[0026] 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.

[0027] Figure 1 The invention provides a synthetic route for the emulsifier for oil-based drilling fluid. DETAILED DESCRIPTION

[0028] 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.

[0029] The present invention provides an emulsifier for oil-based drilling fluid, wherein the emulsifier contains a compound of formula (I):

[0030]

[0031] In formula (I), R 1 C 8 ~C 20 The straight chain alkyl group, R 2 C 8 ~C 20 A straight chain alkyl or C 8 ~C 20 containing a benzene ring alkyl group, Z is X is -H or -OH.

[0032] In the oil-based drilling fluid emulsifier provided by the present invention, in the compound of formula (I), R 1 Specifically, it can be 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 12 ~C 18of a straight chain alkyl group.

[0033] In the oil-based drilling fluid emulsifier provided by the present invention, in the compound of formula (I), when R 2 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.

[0034] In the oil-based drilling fluid emulsifier provided by the present invention, in the compound of formula (I), when R 2 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.

[0035] In the 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 oil-based drilling fluid emulsifier preferably also contains a diluent, and the diluent includes but is not limited to white oil; the addition amount of the diluent is preferably 20-30% of the mass of the compound of the structure of formula (I), specifically 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% or 30%.

[0036] The emulsifier provided by the present invention has a multi-arm structure, and compared with conventional linear emulsifiers, it has better emulsification and temperature resistance, can significantly improve the stability of water-in-oil emulsions under high temperature conditions, and effectively solves the problem of insufficient temperature resistance of existing emulsifiers. Moreover, the emulsifier can be used alone without the use of an auxiliary emulsifier.

[0037] The present invention also provides a method for preparing the oil-based drilling fluid emulsifier described in the above technical solution, comprising the following steps:

[0038] a) reacting a polyacid of formula (i) with a long-chain polyamine of formula (ii) to obtain an intermediate;

[0039] b) mixing the intermediate with a long-chain alkyl acid of formula (iii) to obtain an emulsifier for oil-based drilling fluid;

[0040]

[0041] H 2 N-CH 2 -CH 2 -CH 2 -NH-R 1 Formula (ii);

[0042] HO-ZR 2 Formula (iii);

[0043] In formulas (i) to (iii), R 1 C 5 ~C 20 The straight chain alkyl group, R 2 C 5 ~C 20 A straight chain alkyl or C 5 ~C 20 containing a benzene ring alkyl group, Z is X is -H or -OH.

[0044] In the preparation method provided by the present invention, the synthesis route of the oil-based drilling fluid emulsifier is as follows: Figure 1 As shown, Figure 1 The invention provides a synthetic route for the emulsifier for oil-based drilling fluid.

[0045] In the preparation method provided by the present invention, in step a), the polyacid can be specifically selected from citric acid (i.e., a compound of formula (i) with X=-OH) or trisaccharide (i.e., a compound of formula (i) with X=-H).

[0046] In the preparation method provided by the present invention, in step a), in the long-chain polyamine of formula (ii), R1 Specifically, it can be 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 12 ~C 18 of a straight chain alkyl group.

[0047] In the preparation method provided by the present invention, in step a), the long-chain polyamine can be more specifically selected from N-dodecyl-1,3-propylenediamine, N-tetradecyl-1,3-propylenediamine, N-hexadecyl-1,3-propylenediamine, N-oleyl-1,3-propylenediamine or N-octadecyl-1,3-propylenediamine.

[0048] In the preparation method provided by the present invention, in step a), the molar ratio of the polyacid to the long-chain polyamine is preferably 1:(3-3.1), specifically 1:3, 1:3.01, 1:3.02, 1:3.03, 1:3.04, 1:3.05, 1:3.06, 1:3.07, 1:3.08, 1:3.09 or 1:3.1.

[0049] In the preparation method provided by the present invention, in step a), the temperature of the mixed reaction is preferably 120-140°C, specifically 120°C, 123°C, 125°C, 127°C, 130°C, 132°C, 135°C, 137°C or 140°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.

[0050] In the preparation method provided by the present invention, in step a), the specific process of the mixed reaction is preferably: first, the polyacid is added to the reactor to deoxygenate, and then the long-chain 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.

[0051] In the preparation method provided by the present invention, in step b), in the long-chain alkyl acid of formula (iii), when R 2 Select 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 2 Select 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.

[0052] In the preparation method provided by the present invention, in step b), the long-chain alkyl acid can more specifically be selected from dodecanoic acid, tetradecanoic acid, hexadecanoic acid, oleic acid, stearic acid or dodecylbenzenesulfonic acid.

[0053] In the preparation method provided by the present invention, in step b), the molar ratio of the long-chain alkyl acid to the polyacid of the structure of the intermediate preparation raw material formula (i) is preferably (3-5):1, specifically 3:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4:1, 4.1:1, 4.2:1, 4.3:1, 4.4:1, 4.5:1, 4.6:1, 4.7:1, 4.8:1, 4.9:1 or 5:1.

[0054] 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.

[0055] In the preparation method provided by the present invention, in step b), the specific process of the mixed reaction is preferably: adding a long-chain alkyl acid to the intermediate prepared in step a), and then heating to the reaction temperature for reaction. The reaction temperature corresponds to the temperature of the mixed reaction described above; the reaction time after heating to the reaction temperature corresponds to the time of the mixed reaction described above.

[0056] In the preparation method provided by the present invention, it is preferred to further include the following steps: after completing the mixing 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 the polyacid of formula (i), the long-chain polyamine of formula (ii) and the long-chain alkyl 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.

[0057] The preparation method of the emulsifier for oil-based drilling fluid provided by the invention has simple process, easily controllable conditions and good industrialization prospect.

[0058] 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.

[0059] 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.

[0060] For the purpose of greater clarity, the invention is described in detail through the following examples.

[0061] Example 1

[0062] 1 mol of citric acid was added to a reaction container, nitrogen was passed for 30 minutes to deoxygenate, and then 3.1 mol of N-tetradecyl-1,3-propylenediamine was added under stirring conditions, the temperature was raised to 120°C for reaction for 3 hours, and then 3.5 mol of hexadecanoic acid was added to the reaction container, the system was heated to 170°C for reaction for 2 hours, and the temperature was lowered to 80°C. White oil accounting for 25% of the total mass of the above raw materials was added to the reaction container, and the temperature was lowered to room temperature to obtain an oil-based drilling fluid emulsifier, the chemical structure of which is shown in the following formula:

[0063]

[0064] Example 2

[0065] 1 mol of triacrylic acid was added to a reaction container, nitrogen was passed for 15 minutes to deoxygenate, and then 3 mol of N-oleyl-1,3-propylenediamine was added under stirring conditions, the temperature was raised to 135°C for reaction for 1.5 hours, and then 3 mol of tetradecanoic acid was added to the reaction container, the system was heated to 150°C for reaction for 3 hours, and the temperature was lowered to 100°C. White oil accounting for 30% of the total mass of the above raw materials was added to the reaction container, and the temperature was lowered to room temperature to obtain an oil-based drilling fluid emulsifier, the chemical structure of which is shown in the following formula:

[0066]

[0067] Example 3

[0068] 1 mol of citric acid was added to a reaction container, nitrogen was passed for 10 minutes to deoxygenate, and then 3.05 mol of N-dodecyl-1,3-propylenediamine was added under stirring conditions, the temperature was raised to 140°C for reaction for 1 hour, and then 5 mol of oleic acid was added to the reaction container, the system was heated to 180°C for reaction for 1 hour, and the temperature was lowered to 90°C. White oil accounting for 20% of the total mass of the above raw materials was added to the reaction container, and the temperature was lowered to room temperature to obtain an oil-based drilling fluid emulsifier, the chemical structure of which is shown in the following formula:

[0069]

[0070] Embodiments 4 to 6

[0071] The steps are the same as those in Example 1, and the reaction substances and their amounts are shown in Table 1:

[0072] Table 1 Reaction substances and dosage

[0073] Example Polyacid Long chain polyamine Long chain alkyl acid 4 1 mol citric acid 3.05molN-hexadecyl-1,3-propylenediamine 4.5 mol dodecylbenzenesulfonic acid 5 1 mol triacrylic acid 3molN-Oleyl-1,3-propylenediamine 4mol stearic acid 6 1 mol citric acid 3.1molN-octadecyl-1,3-propylenediamine 3.8mol dodecanoic acid

[0074] Performance Evaluation

[0075] The performance of the oil-based drilling fluid emulsifiers synthesized in Examples 1 to 6 was evaluated, and the specific evaluation contents are as follows:

[0076] (1) Emulsification rate

[0077] 240 mL of 0# diesel and 12 g of the oil-based drilling fluid emulsifier sample prepared in Examples 1 to 6 were added to a high-stirring cup, stirred at 10000 r for 20 min, and then 60 mL of distilled water and 9.0 g of calcium oxide were added, and stirred at high speed for 30 min; the prepared emulsion was loaded into a high-temperature aging tank, placed in a high-temperature roller heating furnace, rolled at 200° C. for 16 h, taken out and cooled, stirred at high speed for 20 min, poured into a 500 mL graduated cylinder, and allowed to stand at room temperature for 24 h, and the volume V of the clear oil separated from the upper layer was observed; the emulsification rate was calculated according to the following formula:

[0078]

[0079] Wherein, W is emulsification rate, %; V is the volume of the oil layer separated in 24 hours, in milliliters (mL).

[0080] Table 2 Emulsification rate of oil-based emulsifier

[0081]

[0082]

[0083] (2) Temperature resistance

[0084] 240mL of 0# diesel was added to a high-stirring cup, and then 15g of the oil-based drilling fluid emulsifier sample prepared in Examples 1 to 6 was 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 drilling fluid density was increased to 1.6g / cm3 with barite, stirred at high speed for 20min, and loaded into an aging tank and rolled at 200°C for aging for 16h to examine the comprehensive performance of the oil-based drilling fluid after high-temperature aging.

[0085] Table 3 Performance evaluation of high temperature resistant oil-based emulsifier

[0086]

[0087] It can be seen from the above evaluation results that the synthetic 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 200° C., and can be used in high-temperature resistant oil-based drilling fluid systems.

[0088] 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 oil-based drilling fluid, It is characterized in that The oil-based drilling fluid emulsifier contains a compound having a structure of formula (I): In formula (I), R 1 C 8 ~C 20 The straight chain alkyl group, R 2 C 8 ~C 20 A straight chain alkyl or C 8 ~C 20 containing a benzene ring alkyl group, Z is X is -H or -OH.

2. The emulsifier for oil-based drilling fluid according to claim 1, It is characterized in that The R 1 C 12 ~C 18 of a straight chain alkyl group.

3. The emulsifier for oil-based drilling fluid according to claim 1, It is characterized in that The R 2 C 11 ~C 18 A straight chain alkyl or C 11 ~C 18 Containing benzene ring alkyl.

4. The emulsifier for oil-based drilling fluid according to claim 1, It is characterized in that The oil-based drilling fluid emulsifier also contains a diluent; the added amount of the diluent is 20-30% of the mass of the compound with the structure of formula (I).

5. A method for preparing the emulsifier for oil-based drilling fluid according to any one of claims 1 to 4, It is characterized in that The following steps are involved: a) reacting a polyacid of formula (i) with a long-chain polyamine of formula (ii) to obtain an intermediate; b) mixing the intermediate with a long-chain alkyl acid of formula (iii) to obtain an emulsifier for oil-based drilling fluid; H 2 N-CH 2 -CH 2 -CH 2 -NH-R 1 Formula (ii); HO-Z-R 2 Formula (iii); In formulas (i) to (iii), R 1 C 5 ~C 20 The straight chain alkyl group, R 2 C 5 ~C 20 A straight chain alkyl or C 5 ~C 20 containing a benzene ring alkyl group, Z is X is -H or -OH.

6. The preparation method according to claim 5, It is characterized in that The long-chain polyamine is N-dodecyl-1,3-propylenediamine, N-tetradecyl-1,3-propylenediamine, N-hexadecyl-1,3-propylenediamine, N-oleyl-1,3-propylenediamine or N-octadecyl-1,3-propylenediamine; The long-chain alkyl acid is lauric acid, myristic acid, hexadecanoic acid, oleic acid, stearic acid or dodecylbenzenesulfonic acid.

7. The preparation method according to claim 5, It is characterized in that The molar ratio of the polyacid, the long-chain polyamine and the long-chain alkyl acid is 1:(3-3.1):(3-5).

8. The preparation method according to claim 5, It is characterized in that In step a), the temperature of the mixed reaction is 120-140° C., and the time of the mixed reaction is 1-3 hours; In step b), the temperature of the mixed reaction is 150-180° C., and the time of the mixed reaction is 1-3 hours.

9. The preparation method according to claim 5, It is characterized in that Also includes: After the mixing reaction in 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 oil-based drilling fluid emulsifier according to any one of claims 1 to 4 or the oil-based drilling fluid emulsifier prepared by the preparation method according to any one of claims 5 to 9.

Images