Emulsifier composition for oil-based drilling fluid and preparation method thereof

Abstract

The present invention provides an emulsifier composition for oil-based drilling fluid and a preparation method thereof, belonging to the field of petroleum drilling technology. The emulsifier composition for oil-based drilling fluid comprises the following raw materials, with the sum of weight percentages being 100%: modified tall oil, 25-40%; fatty acid amide, 5-15%; polyol, 5-15%; base oil, 25-40%; auxiliary emulsifier, 5-10%; and phosphate surfactant, 1-5%. The modified tall oil, fatty acid amide, and polyol are first heat-treated at 80-100°C for reaction before being mixed with the remaining raw materials. The emulsifier composition of the present invention has good compatibility with oil-based drilling fluid and possesses excellent thermal stability, storage stability, and emulsification efficiency, thereby appropriately reducing the cost of use.

Description

Technical Field

[0001] The present invention relates to the technical field of petroleum drilling, in particular to an emulsifier composition for oil-based drilling fluid and a preparation method thereof. Background Art

[0002] Oil-based drilling fluid plays an important role in drilling in complex formations due to its excellent lubricity, inhibition, high temperature resistance and anti-pollution capabilities, and the emulsifiers used in it play a key role in maintaining the stability of the oil-based drilling fluid system.

[0003] Traditional emulsifiers primarily include oleic acid, the Span series (such as Span-80 and Span-85), divalent metal soaps of fatty acids, fatty acid esters, and cationic amine salts (such as hexadecyltrimethylammonium bromide). These emulsifiers have limited heat resistance and are prone to degradation or desorption from the oil-water interface at high temperatures, destabilizing the water-in-oil drilling fluid. Furthermore, when used alone, they require large quantities and are costly.

[0004] The Chinese invention application (title: "An Emulsifier Composition and Its Preparation Method," publication number: CN105524601A, publication date: April 27, 2016) discloses an emulsifier composition comprising a primary emulsifier, a secondary emulsifier, and a base oil. The primary emulsifier is an oxidized polymerized fatty acid ester, and the secondary emulsifier is a polyamide. The emulsifier composition provided by the present invention utilizes an oxidized polymerized fatty acid ester and a polyamide as the primary and secondary emulsifiers, respectively, increasing the composition's emulsification efficiency and improving its electrical stability, facilitating its preparation and use in oil-based drilling fluids. However, the emulsifier composition's salt, calcium, and high-temperature resistance needs further improvement. Summary of the Invention

[0005] The present invention aims to provide an emulsifier composition for oil-based drilling fluid and a preparation method thereof, which has good compatibility with oil-based drilling fluid and has excellent thermal stability, salt and calcium resistance, storage stability and emulsification efficiency, and can appropriately reduce the cost of use.

[0006] The technical solution adopted in the present invention is:

[0007] An emulsifier composition for oil-based drilling fluid, comprising the following raw materials, with the sum of weight percentages being 100%:

[0008] Modified pine oil, 25-40%;

[0009] Fatty acid amide, 5-15%;

[0010] Polyols, 5-15%;

[0011] Base oil, 25-40%;

[0012] Auxiliary emulsifier, 5~10%;

[0013] Phosphate surfactant, 1~5%;

[0014] The modified tall oil, the fatty acid amide and the polyol are first subjected to a heat treatment reaction at 80-100° C. and then mixed with the remaining raw materials.

[0015] Furthermore, the modified pine oil is prepared by using pine oil and calcium stearate or zinc stearate in a weight ratio of 100:15-20.

[0016] Furthermore, the fatty acid amide is prepared by condensing C8-C18 fatty acids and their derivatives with amine compounds.

[0017] Furthermore, the fatty acid amide is prepared from coconut oil methyl ester and diethanolamine, or stearic acid and hydroxyethylethylenediamine, or lauric acid and hydroxyethylethylenediamine.

[0018] Furthermore, the polyol is one or more of pentaerythritol, ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol and glycerol.

[0019] Furthermore, the base oil is white oil or diesel.

[0020] Furthermore, the auxiliary emulsifier is one or more of polyoxyethylene hydrogenated castor oil, glyceryl monostearate, fatty acid polyglycerol ester, Span series surfactant or Tween series surfactant.

[0021] Furthermore, the phosphate surfactant is alkyl polyoxyethylene ether phosphate salt and alkyl phosphate salt.

[0022] Based on the same inventive concept, the present invention also provides a method for preparing an emulsifier composition for oil-based drilling fluid, comprising the following steps:

[0023] Step S1, adding modified pine oil, fatty acid amide and polyol into a reaction kettle according to a proportion, then heating to 80-100° C., stirring and heat-treating for 1-2 hours;

[0024] Step S2: adding base oil, auxiliary emulsifier and phosphate surfactant at a temperature lower than the heat treatment reaction temperature in step S1, maintaining the temperature and stirring for 1 to 2 hours to obtain an emulsifier composition for oil-based drilling fluid.

[0025] Furthermore, the temperature of the stirring and mixing in step S2 is 60-70°C.

[0026] The beneficial effects of the present invention are:

[0027] 1. The emulsifier composition for oil-based drilling fluid of the present invention is formed by heat-treating the reaction product of modified loose oil, fatty acid amide and polyol at 80-100°C, supplemented with an auxiliary emulsifier and a phosphate surfactant. The composition has good compatibility with oil-based drilling fluid and has excellent thermal stability, salt and calcium resistance, storage stability and emulsification efficiency, and can meet the needs of long-term drilling operations. Compared with a single-component emulsifier, the usage amount of the emulsifier composition for oil-based drilling fluid of the present invention can be greatly reduced, and the cost of use can be appropriately reduced.

[0028] 2. The addition of a phosphate surfactant to the oil-based drilling fluid emulsifier composition of the present invention significantly improves the salt and calcium resistance of the emulsifier composition, making it suitable for drilling in high-mineralization formations.

[0029] 3. The preparation method of the emulsifier composition for oil-based drilling fluid in the present invention has a relatively simple process, low requirements on equipment, and is easy to industrialize. DETAILED DESCRIPTION

[0030] The embodiments of the invention are described in detail below.

[0031] Example 1

[0032] 25 wt% of modified pine oil (prepared by combining pine oil and zinc stearate in a weight ratio of 100:15), 20 wt% of fatty acid amide (prepared by combining lauric acid and hydroxyethylethylenediamine in a molar ratio of 1:1), and 5 wt% of neopentyl glycol were added to a reactor according to a certain ratio, and then heated to 80° C. and stirred for a heat treatment reaction for 2 hours. The temperature of the mixture in the reactor was lowered to 65° C., and 40 wt% of 5# white oil, 5 wt% of SP-80, 2 wt% of Tween-80, and 3 wt% of potassium dodecyl phosphate were added. The mixture was kept warm and stirred for 2 hours to obtain an emulsifier composition for an oil-based drilling fluid.

[0033] Example 2

[0034] 30 wt% of modified pine oil (prepared by combining pine oil and zinc stearate in a weight ratio of 100:15), 10 wt% of fatty acid amide (prepared by combining lauric acid and hydroxyethylethylenediamine in a molar ratio of 1:1), and 10 wt% of neopentyl glycol were added to a reactor according to a certain ratio, and then heated to 80° C. and stirred for a heat treatment reaction for 2 hours. The temperature of the mixture in the reactor was lowered to 65° C., and 40 wt% of 5# white oil, 5 wt% of SP-80, 2 wt% of Tween-80, and 3 wt% of potassium dodecyl phosphate were added. The mixture was kept warm and stirred for 2 hours to obtain an emulsifier composition for an oil-based drilling fluid.

[0035] Example 3

[0036] 40 wt% of modified pine oil (prepared by combining pine oil and zinc stearate in a weight ratio of 100:15), 5 wt% of fatty acid amide (prepared by combining lauric acid and hydroxyethylethylenediamine in a molar ratio of 1:1), and 15 wt% of neopentyl glycol were added to a reactor according to a certain ratio, and then heated to 80° C. and stirred for a heat treatment reaction for 2 hours. The temperature of the mixture in the reactor was lowered to 65° C., and 30 wt% of 5# white oil, 5 wt% of SP-80, 2 wt% of Tween-80, and 3 wt% of potassium dodecyl phosphate were added. The mixture was kept warm and stirred for 2 hours to obtain an emulsifier composition for an oil-based drilling fluid.

[0037] Example 4

[0038] 25 wt% of modified pine oil (prepared by combining pine oil and zinc stearate in a weight ratio of 100:15), 20 wt% of fatty acid amide (prepared by combining lauric acid and hydroxyethylethylenediamine in a molar ratio of 1:1), and 5 wt% of pentaerythritol were added to a reactor according to a certain ratio, and then heated to 80° C. and stirred for a heat treatment reaction for 2 hours. The temperature of the mixture in the reactor was lowered to 65° C., and 40 wt% of 5# white oil, 5 wt% of SP-80, 2 wt% of Tween-80, and 3 wt% of potassium dodecyl phosphate were added. The mixture was kept warm and stirred for 2 hours to obtain an emulsifier composition for an oil-based drilling fluid.

[0039] Example 5

[0040] 25 wt% of modified pine oil (prepared by combining pine oil and zinc stearate in a weight ratio of 100:15), 20 wt% of fatty acid amide (prepared by combining lauric acid and hydroxyethylethylenediamine in a molar ratio of 1:1), and 5 wt% of glycerol were added to a reactor according to a certain ratio, and then heated to 80° C. and stirred for a heat treatment reaction for 2 hours. The temperature of the mixture in the reactor was lowered to 65° C., and 40 wt% of 5# white oil, 5 wt% of SP-80, 2 wt% of Tween-80, and 3 wt% of potassium dodecyl phosphate were added. The mixture was kept warm and stirred for 2 hours to obtain an emulsifier composition for an oil-based drilling fluid.

[0041] Example 6

[0042] 30 wt% of modified pine oil (prepared by combining pine oil with zinc stearate in a weight ratio of 100:15), 10 wt% of fatty acid amide (prepared by combining stearic acid with hydroxyethylethylenediamine in a molar ratio of 1:1), and 10 wt% of neopentyl glycol were added to a reactor according to a certain ratio, and then heated to 100° C. and stirred for a heat treatment reaction for 1 hour. The temperature of the mixture in the reactor was lowered to 65° C., and 40 wt% of 5# white oil, 9 wt% of SP-80, and 1 wt% of potassium dodecyl phosphate were added. The mixture was kept warm and stirred for 2 hours to obtain an emulsifier composition for an oil-based drilling fluid.

[0043] Example 7

[0044] 30 wt% of modified pine oil (prepared from pine oil and zinc stearate in a weight ratio of 100:15), 10 wt% of fatty acid amide (prepared from coconut oil methyl ester and diethanolamine in a molar ratio of 1:1), and 10 wt% of neopentyl glycol were added to a reactor according to a proportion, and then heated to 90° C. and stirred for a heat treatment reaction for 1.5 hours. The temperature of the mixture in the reactor was lowered to 65° C., and 40 wt% of 5# white oil, 5 wt% of SP-80, and 5 wt% of potassium lauryl phosphate were added. The mixture was kept warm and stirred for 2 hours to obtain an emulsifier composition for an oil-based drilling fluid.

[0045] Comparative Example 1

[0046] 50 wt% of modified pine oil (prepared by pine oil and zinc stearate in a weight ratio of 100:15) was added to a reactor, which was then heated to 80°C and stirred for a heat treatment reaction for 2 hours. The temperature of the mixture in the reactor was lowered to 65°C, and 40 wt% of 5# white oil, 5 wt% of SP-80, 2 wt% of Tween-80, and 3 wt% of potassium dodecyl phosphate were added. The mixture was kept warm and stirred for 2 hours to obtain an emulsifier composition for an oil-based drilling fluid.

[0047] Comparative Example 2

[0048] 30 wt% of modified pine oil (prepared by combining pine oil and zinc stearate in a weight ratio of 100:15), 10 wt% of fatty acid amide (prepared by combining lauric acid and hydroxyethylethylenediamine in a molar ratio of 1:1), and 10 wt% of neopentyl glycol were added to a reactor according to a proportion, and then heated to 65° C. and stirred for a heat treatment reaction for 2 hours. The temperature of the mixture in the reactor was lowered to 65° C., and 40 wt% of 5# white oil, 5 wt% of SP-80, 2 wt% of Tween-80, and 3 wt% of potassium dodecyl phosphate were added. The mixture was kept warm and stirred for 2 hours to obtain an emulsifier composition for an oil-based drilling fluid.

[0049] Comparative Example 3

[0050] 30 wt% of modified pine oil (prepared by pine oil and zinc stearate in a weight ratio of 100:15), 10 wt% of fatty acid amide (prepared by lauric acid and hydroxyethylethylenediamine in a molar ratio of 1:1), 10 wt% of neopentyl glycol, 40 wt% of 5# white oil, 5 wt% of SP-80, 2 wt% of Tween-80 and 3 wt% of potassium dodecyl phosphate were added into a reactor according to a proportion, and then heated to 80°C, stirred and heat-treated for 4 hours to obtain an emulsifier composition for oil-based drilling fluid.

[0051] Comparative Example 4

[0052] 30 wt% of modified pine oil (prepared by combining pine oil and zinc stearate in a weight ratio of 100:15), 10 wt% of fatty acid amide (prepared by combining lauric acid and hydroxyethylethylenediamine in a molar ratio of 1:1), and 10 wt% of neopentyl glycol were added to a reactor according to a certain ratio, and then heated to 80°C and stirred for a heat treatment reaction for 2 hours. The temperature of the mixture in the reactor was lowered to 65°C, and 40 wt% of 5# white oil, 5 wt% of SP-80, and 5 wt% of Tween-80 were added. The mixture was kept warm and stirred for 2 hours to obtain an emulsifier composition for an oil-based drilling fluid.

[0053] Experimental Method: 300 mL of 5# white oil and 20 g of the low-cost oil-based drilling fluid emulsifier composition prepared in Examples 1-7 and Comparative Examples 1-4 were added to a high-stirring beaker, followed by stirring at 11,000 rpm for 10 minutes. Then, 100 mL of a 25% calcium chloride saline solution was slowly added and stirred at high speed for 20 minutes. Then, 8 g of calcium oxide and 14 g of organobentonite were slowly added and stirred at high speed for 60 minutes. The prepared emulsion was placed in a high-temperature aging kettle and aged at 150°C for 16 hours. After cooling to room temperature, the emulsion was stirred at high speed for 10 minutes. The rheological properties and demulsification voltage were tested according to the methods specified in GB / T 16783.2 at 50°C. The test results are shown in the table below.

[0054] Table 1 Test results

[0055]

[0056] Continued Table 1-1

[0057]

[0058] From the test results in the above table, it can be seen that the oil-based drilling fluid base emulsion prepared using the low-cost oil-based drilling fluid emulsifier composition of this embodiment has high emulsification efficiency, an emulsion breaking voltage greater than 500V, and good salt and calcium resistance.

Claims

1. An emulsifier composition for oil-based drilling fluid, characterized in that: The sum of weight percentages is 100%, and includes the following raw materials: Modified pine oil, 25-40%; Fatty acid amide, 5-15%; Polyols, 5-15%; Base oil, 25-40%; Auxiliary emulsifier, 5~10%; Phosphate surfactant, 1~5%; The modified tall oil, the fatty acid amide and the polyol are first subjected to a heat treatment reaction at 80-100° C. and then mixed with the remaining raw materials; The modified pine oil is prepared by mixing pine oil with calcium stearate or zinc stearate in a weight ratio of 100:15-20; The fatty acid amide is prepared by condensing C8~C18 fatty acids and their derivatives with amine compounds; The auxiliary emulsifier is one or more of polyoxyethylene hydrogenated castor oil, glyceryl monostearate, fatty acid polyglycerol ester, Span series surfactant or Tween series surfactant; The phosphate surfactant is an alkyl phosphate salt.

2. The emulsifier composition for oil-based drilling fluid according to claim 1, characterized in that The fatty acid amide is prepared from coconut oil methyl ester and diethanolamine, or stearic acid and hydroxyethylethylenediamine, or lauric acid and hydroxyethylethylenediamine.

3. The emulsifier composition for oil-based drilling fluid according to claim 1, characterized in that The polyol is one or more of pentaerythritol, ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol and glycerol.

4. The emulsifier composition for oil-based drilling fluid according to claim 1, characterized in that The base oil is white oil or diesel.

5. A method for preparing an emulsifier composition for oil-based drilling fluid, to obtain the emulsifier composition for oil-based drilling fluid according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step S1, adding modified pine oil, fatty acid amide and polyol into a reaction kettle according to a proportion, then heating to 80-100° C., stirring and heat-treating for 1-2 hours; Step S2: adding base oil, auxiliary emulsifier and phosphate surfactant at a temperature lower than the heat treatment reaction temperature in step S1, maintaining the temperature and stirring for 1 to 2 hours to obtain an emulsifier composition for oil-based drilling fluid. 6 . The method for preparing an emulsifier composition for oil-based drilling fluid according to claim 5 , wherein the temperature of the stirring and mixing in step S2 is 60-70° C.

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