Viscosity reducer as well as preparation method and application thereof

Abstract

The invention provides a viscosity reducer as well as a preparation method and application thereof. The invention provides a viscosity reducer which comprises the following raw materials in parts by weight: 10-50 parts of a non-polar component A, 10-60 parts of a polar component B and 30-50 parts of a surfactant C, the non-polar component A is selected from one or more of octane, petroleum ether, dotridecane, octacosane, carbon disulfide, carbon tetrachloride, ethane, cyclohexane, liquid paraffin, ethyl acetate and diethylene glycol monobutyl ether; the polar component B is prepared by reaction of styrene, maleic anhydride and acrylate; the surfactant C is prepared by reacting the polar component B, organic acid and polyamine. According to the viscosity reducer for the oil-based drilling fluid, provided by the invention, the viscosity and the shearing force of the oil-based drilling fluid can be remarkably reduced, the flowability of the oil-based drilling fluid is improved, and particularly, the viscosity and the shearing force of the polluted oil-based drilling fluid can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of drilling fluids, and in particular to a viscosity reducer and a preparation method and application thereof. Background Art

[0002] As the exploration conditions of oil-based drilling fluids become more stringent, the density requirements are constantly increasing, and the amount of weighting materials is constantly increasing, which makes the viscosity of the drilling fluids continue to increase. 3 For oil-based drilling fluid, viscosity reducer becomes one of the key treatment agents. In the process of preparing and using oil-based drilling fluid, the viscosity of drilling fluid will exceed the standard. In particular, in order to reduce costs, oil-based drilling fluid is reused many times, and the content of inferior solid phase in drilling fluid continues to increase, and drilling fluid over-thickness becomes a common phenomenon. In addition, during the drilling process, high-wax and asphalt-containing crude oil in the formation invades the drilling fluid, which becomes one of the reasons for the thickening of oil-based drilling fluid. When the bottom hole temperature is high, wax dissolves in the base oil, colloid and asphaltene are suspended and dispersed in the oil, and the apparent viscosity of the drilling fluid is acceptable. When the drilling fluid is in a ground tank and the temperature is low, colloid and asphaltene associate, increasing the viscosity of the system, and wax precipitates from the base oil to form a network structure that wraps the base oil, which deteriorates the fluidity of the drilling fluid.

[0003] At this time, adding a certain amount of viscosity reducer becomes a necessary option for on-site treatment. The general principle of the viscosity reducer for oil-based drilling fluid is that the viscosity reducer itself has surface activity. By improving the lipophilicity of the solid phase and increasing the capacity of the oil phase, the viscosity reducer is wrapped on the surface of the solid phase to reduce the interaction between the solid phases. Or the viscosity reducer molecules contain negatively charged functional groups that can react with clay, preventing it from forming a grid structure, thereby reducing shear force and improving rheology. However, this type of viscosity reducer has limited effect on the deterioration of flow patterns caused by heavy oil pollution.

[0004] However, the viscosity reducers for drilling fluids in the prior art cannot improve the problems of repeated use of oil-based drilling fluids, increasing levels of inferior solids in the drilling fluids, excessive viscosity of the drilling fluids, or intrusion of high-wax and asphalt-containing crude oils into the drilling fluids during drilling, causing the drilling fluids to thicken, thereby causing the viscosity of the drilling fluids to exceed the standard and deteriorating the fluidity of the drilling fluids.

[0005] Patent application CN104152122A introduces a viscosity reducer for oil-based drilling fluid, which is a terpolymer composed of polyethylene glycol, maleic anhydride and polyethylene polyamine, and the molecular weight of polyethylene glycol is 200-2000. Using diesel as a solvent, polyethylene glycol and maleic anhydride are reacted to obtain an ester compound; polyethylene polyamine is added to the ester compound to obtain a terpolymer. The product contains -OH, -COO-, and -CONH- groups, which can form hydrogen bonds with organic groups in organic soil, thereby effectively breaking up the interaction between organic groups and oil in organic soil. However, the viscosity reducer only combines with clay through functional groups, and does not solve the thickening problem caused by heavy oil, weighting materials, and inferior solid phases. Summary of the invention

[0006] In order to solve the above problems in the prior art, the present invention provides a viscosity reducer and a preparation method and application thereof.

[0007] In a first aspect, the present invention provides a viscosity reducer, comprising the following raw materials by weight: 10 to 50 parts of a non-polar component A, 10 to 60 parts of a polar component B and 30 to 50 parts of a surfactant C;

[0008] The non-polar component A is selected from one or more of octane, petroleum ether, tridecane, octacosane, carbon disulfide, carbon tetrachloride, ethane, cyclohexane, liquid paraffin, ethyl acetate, and diethylene glycol butyl ether;

[0009] The polar component B is prepared by reacting styrene, maleic anhydride and acrylic ester;

[0010] Surfactant C is prepared by reacting polar component B, organic acid and polyamine.

[0011] As a specific embodiment of the present invention, acrylate is prepared from acrylic acid and long-chain alkanol, and the conditions for preparing polar component B include: the mass ratio of acrylic acid, long-chain alkanol, styrene and maleic anhydride is (90-120):(240-300):(20-40):(80-110).

[0012] As a specific embodiment of the present invention, the conditions for the reaction of acrylic acid with a long-chain alkanol include: a temperature of 120 to 140° C. and a time of 2 to 3 hours.

[0013] As a specific embodiment of the present invention, the reaction conditions of styrene, maleic anhydride and acrylic ester include: temperature of 110-120° C. and time of 6-8 hours.

[0014] As a specific embodiment of the present invention, the long-chain alkanol is selected from C 8 -C 22 One or more of the alcohols.

[0015] As a specific embodiment of the present invention, the conditions for preparing surfactant C include: the mass ratio of polar component B, organic acid, and polyamine is (40-60): (110-130): (20-40).

[0016] As a specific embodiment of the present invention, in the process of preparing surfactant C, the reaction conditions of polar component B, organic acid and polyamine include: temperature of 160-180° C. and time of 2-3 hours.

[0017] As a specific embodiment of the present invention, the organic acid is selected from one or more of tall oil acid, stearic acid, lauric acid, capric acid, palmitic acid, rosin acid, dodecylbenzenesulfonic acid, behenic acid, linolenic acid and adipic acid.

[0018] As a specific embodiment of the present invention, the polyamine is selected from one or more of polyethylene polyamine, diethylene triamine, triethylene tetraamine and tetraethylene pentamine.

[0019] In a second aspect, the present invention provides a method for preparing the viscosity reducer provided in the first aspect of the present invention, comprising: mixing a non-polar component A, a polar component B and a surfactant C to prepare the viscosity reducer.

[0020] As a specific embodiment of the present invention, the preparation method of the viscosity reducer provided in the first aspect of the present invention comprises the following steps: mixing the non-polar component A, the polar component B and the surfactant C, heating to 80-100°C, stirring, keeping warm for 1-2h, and cooling to room temperature to obtain the viscosity reducer.

[0021] In a third aspect, the present invention provides an application of the viscosity reducer provided in the first aspect of the present invention or the viscosity reducer prepared by the preparation method provided in the second aspect of the present invention in drilling fluid, specifically, application in oil-based drilling fluid.

[0022] Preferably, the volume ratio of the viscosity reducer to the drilling fluid is 3% to 5%.

[0023] Compared with the prior art, the present invention has the following beneficial effects.

[0024] (1) The present invention provides a viscosity reducer for oil-based drilling fluid, which can significantly reduce the viscosity and shear force of the oil-based drilling fluid, improve the fluidity of the oil-based drilling fluid, and especially reduce the viscosity and shear force of the contaminated oil-based drilling fluid.

[0025] (2) The viscosity reducer provided by the present invention can be used to treat the deterioration of the flow pattern of drilling fluid caused by high-quality solid phase, oil and gas pollution, etc. The electrical repulsion between the layers of the inferior solid phase and the attraction of the end faces to form a grid structure, and the increase in the viscosity of the liquid phase of the drilling fluid after oil and gas pollution, all of which cause the flow pattern to deteriorate. The viscosity reducer component of the present invention can form a wrap around the solid phase, reduce the formation of the grid structure in the drilling fluid, and change the wettability of the solid phase to increase the tolerance of the solid phase in the polar outer term. The polar and non-polar components can dissolve part of the intruding substances, and cooperate with the solid control treatment of the drilling fluid to achieve the optimal flow pattern of the oil-based drilling fluid.

[0026] (3) The present invention provides a viscosity reducer for oil-based drilling fluid, which is applied to oil-based drilling fluid and can effectively improve the viscosity reduction rate and reduce the circulating pump pressure.

[0027] (4) The present invention provides a viscosity reducer for oil-based drilling fluid, which has a simple preparation process, convenient operation, low cost, stable product quality and high economic value.

[0028] (5) The viscosity reducer for oil-based drilling fluid provided by the present invention can be applied to the reprocessing of the old oil-based drilling fluid slurry after well completion for reuse, and can effectively improve the fluidity and reuse value of the old oil-based drilling fluid slurry. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with specific embodiments, but they do not constitute any limitation to the present invention.

[0030] Example 1

[0031] A viscosity reducer for oil-based drilling fluid comprises 150 g of a non-polar component A, 140 g of a polar component B and 170 g of a surfactant C. The three components are mixed, heated to 80° C., stirred for 5 minutes, and kept warm for 1 hour to obtain 460 g of a composite viscosity reducer.

[0032] Wherein, component A is selected from ethyl acetate;

[0033] The preparation process of component B includes: adding 270g of octadecyl alcohol to a three-necked flask reaction device equipped with an electric stirrer, a reflux condenser and a water separator, heating to 70°C to melt it. Under stirring conditions, add 2g of inhibitor hydroquinone, 3g of catalyst p-toluenesulfonic acid, 150g of water-carrying agent cyclohexane and 90g of methacrylic acid in sequence. Slowly heat to 125°C, react for 2 hours, condense 15.8mL of water to obtain a reaction product. Place the reaction product in a separatory funnel and wash with 5% NaOH solution until the water layer is colorless. Put all the reaction products 332g back into the above reactor, add 34g of styrene, 98g of maleic anhydride and 50g of toluene (solvent), stir and heat to 110°C, pass nitrogen to drive oxygen for 30min, add 5g of AIBN initiator, keep warm and react for 7 hours to obtain component B.

[0034] Preparation process of component C: Use the same reaction apparatus as that of component B, weigh 40 g of component B, 120 g of tall oil fatty acid, and 20 g of diethylenetriamine, gradually heat to 170°C for 2 h, condense 5.2 mL of water under vacuum, and cool to obtain component C.

[0035] Example 2

[0036] A viscosity reducer for oil-based drilling fluid comprises 150g of non-polar component A, 150g of polar component B and 200g of surfactant C. The three components are mixed, heated to 85°C, stirred for 5min, and kept warm for 1 hour to obtain 500g of composite viscosity reducer.

[0037] Wherein, component A is petroleum ether;

[0038] The preparation process of component B includes: adding 300g of heneicosanol to a three-necked flask equipped with an electric stirrer, a reflux condenser and a water separator, heating to 70°C to melt it. Under stirring conditions, add 2g of hydroquinone as an inhibitor, 3g of p-toluenesulfonic acid as a catalyst, 200g of cyclohexane as a water-carrying agent and 110g of methacrylic acid in sequence. Slowly heat to 130°C, react for 2.5 hours, condense 16mL of water to obtain a reaction product. Place the reaction product in a separatory funnel and wash with a 5% NaOH solution until the water layer is colorless. Put all the reaction products 490g back into the above reactor, add 35g of styrene, 100g of maleic anhydride and 50g of toluene (solvent), stir and heat to 115°C, pass nitrogen to drive out oxygen for 30min, add 5g of AIBN initiator, keep warm and react for 8 hours to obtain component B.

[0039] The preparation process of component C includes: using the same reaction device as the preparation process of component B, weighing 60g of component B, 130g of palmitic acid, and 20g of diethylenetriamine, gradually heating to 175°C for 2h, vacuuming and condensing 8.2mL of water, and cooling to obtain component C.

[0040] Example 3

[0041] A viscosity reducer for oil-based drilling fluid comprises 200 g of non-polar component A, 100 g of polar component B and 180 g of surfactant C. The three components are mixed, heated to 85° C., stirred for 5 minutes, and kept warm for 1 hour to obtain 480 g of a composite viscosity reducer.

[0042] Wherein, component A is diethylene glycol butyl ether;

[0043] The preparation process of component B includes: adding 240g of palm alcohol to a three-necked flask equipped with an electric stirrer, a reflux condenser and a water separator, heating to 55°C to melt it. Under stirring conditions, add 1g of hydroquinone as an inhibitor, 2g of p-toluenesulfonic acid as a catalyst, 100g of cyclohexane as a water-carrying agent and 100g of methacrylic acid in sequence. Slowly heat to 130°C, react for 2 hours, condense 14.8mL of water to obtain a reaction product. Place the reaction product in a separatory funnel and wash with a 5% NaOH solution until the water layer is colorless. Put all the reaction products (325g) back into the above reactor, add 30g of styrene, 100g of maleic anhydride and 50g of toluene (solvent), stir and heat to 115°C, pass nitrogen to drive out oxygen for 30min, add 3g of AIBN initiator, keep warm and react for 8 hours to obtain component B.

[0044] The preparation process of component C includes: using the same device as the preparation process of component B, weighing 40g of component B, 130g of palmitic acid, and 30g of diethylenetriamine, gradually heating to 180°C, reacting for 2h, vacuuming and condensing 8.0mL of water, and cooling to obtain component C.

[0045] Comparative Example 1

[0046] The specific process is as follows: add 270g of octadecyl alcohol to a three-necked flask equipped with an electric stirrer, a reflux condenser and a water separator, and heat it to 70°C to melt it. Under stirring conditions, add 2g of inhibitor hydroquinone, 3g of catalyst p-toluenesulfonic acid, 150g of water-carrying agent cyclohexane and 90g of acrylic acid in sequence. Slowly heat to 125°C, react for 2 hours, condense 15.6mL of water to obtain a reaction product. Place the reaction product in a separatory funnel and wash with 5% NaOH solution until the water layer is colorless. Put all the reaction products 330g back into the above reactor, add 40g of styrene, 100g of maleic anhydride and 200g of toluene, stir and heat to 110°C, pass nitrogen to drive oxygen for 30min, add 4g of BPO initiator, keep warm and react for 6 hours to obtain an oil-based drilling fluid viscosity reducer.

[0047] Performance Testing

[0048] First, drilling fluid was prepared, and then the drilling fluid was contaminated with inferior solid phase and crude oil, and then the viscosity and shear effects of the above-mentioned Examples 1 to 3 and Comparative Example 1 on the contaminated drilling fluid were tested.

[0049] Drilling fluid formula: 240mL white oil + 2.5% primary emulsifier + 1.5% auxiliary emulsifier + 2% wetting agent + 2.5% organic soil + 3% calcium oxide + 5% oxidized asphalt + 60mL calcium chloride aqueous solution (the mass volume ratio of calcium chloride to water in the calcium chloride aqueous solution is 25%) + 600g barite (to increase the formula density to 1.90g / cm 3). The percentage of primary emulsifier, auxiliary emulsifier, wetting agent, organic soil, calcium oxide and oxidized asphalt added to the drilling fluid formula is the mass volume ratio, and the volume of the drilling fluid is based on 300mL. For example, 2.5% of the primary emulsifier is the percentage of the mass of the emulsifier to the volume of the drilling fluid (300mL).

[0050] The inferior solid phase is made of shale rock chips, which are crushed and passed through a 120-mesh sieve.

[0051] The crude oil selected is waxy crude oil from a shale well in a certain area.

[0052] The samples to be tested were aged by rolling at 200℃ for 16h. At 65℃, the electrical stability before and after aging was measured using an electrical stability meter, the plastic viscosity, dynamic shear force and static shear force before and after aging were measured using a six-speed viscometer, and the settlement after aging was tested using a steel ruler sedimentation meter. The test results are shown in Table 1.

[0053] The percentage content in the formula in the table below refers to the mass ratio of the added substance to the volume ratio of the drilling fluid formula, and the volume of the drilling fluid formula is based on 300mL. For example, the drilling fluid formula + 10% inferior solid phase is: drilling fluid formula + inferior solid phase accounting for 10% of the mass volume of the drilling fluid formula, where the volume of the drilling fluid formula is based on 300mL.

[0054] Table 1 Test data of viscosity reducers prepared in Examples and Comparative Examples

[0055]

[0056] It can be seen from the data in Table 1 that after the oil-based drilling fluid is contaminated by inferior solid phase and crude oil, the viscosity and shear of the oil-based drilling fluid increase after aging. In particular, after the oil-based drilling fluid is contaminated by inferior solid phase, the fluidity of the oil-based drilling fluid is extremely poor after aging. By adding the viscosity reducer of the present invention to the contaminated oil-based drilling fluid, the viscosity and shear of the contaminated oil-based drilling fluid before and after aging are significantly reduced, and the viscosity reduction effect is significantly higher than that of the viscosity reducer in Comparative Example 1, and the viscosity reducer in Comparative Example 1 has a poor effect on the contaminated drilling fluid. It can be seen that the viscosity reducer of the oil-based drilling fluid of the present invention can significantly reduce the viscosity and shear force of the contaminated oil-based drilling fluid, improve the fluidity of the oil-based drilling fluid, reduce the circulating pump pressure, and realize the recycling of the oil-based drilling fluid.

[0057] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A viscosity reducer, characterized in that: The invention comprises the following raw materials in weight components: 10 to 50 parts of non-polar component A, 10 to 60 parts of polar component B and 30 to 50 parts of surfactant C; The non-polar component A is selected from one or more of octane, petroleum ether, tridecane, octacosane, carbon disulfide, carbon tetrachloride, ethane, cyclohexane, liquid paraffin, ethyl acetate, and diethylene glycol butyl ether; The polar component B is prepared by reacting styrene, maleic anhydride and acrylic ester; The surfactant C is prepared by reacting the polar component B, an organic acid and a polyamine.

2. The viscosity reducer according to claim 1, characterized in that The acrylic acid ester is prepared from acrylic acid and long-chain alkanol. The conditions for preparing the polar component B include: the mass ratio of acrylic acid, long-chain alkanol, styrene and maleic anhydride is (90-120):(240-300):(20-40):(80-110).

3. The viscosity reducer according to claim 2, characterized in that The reaction conditions of acrylic acid and long-chain alkanol include: temperature of 120-140° C. and time of 2-3 hours; and / or, the reaction conditions of styrene, maleic anhydride and acrylic ester include: temperature of 110-120° C. and time of 6-8 hours.

4. The viscosity reducer according to claim 2 or 3, characterized in that The long chain alkanol is selected from the group consisting of C8-C 22 One or more of the alcohols.

5. The viscosity reducer according to claim 4, characterized in that The conditions for preparing surfactant C include: the mass ratio of polar component B, organic acid and polyamine is (40-60):(110-130):(20-40).

6. The viscosity reducer according to claim 5, characterized in that In the process of preparing surfactant C, the reaction conditions of the polar component B, organic acid and polyamine include: temperature of 160-180° C. and reaction time of 2-3 hours.

7. The viscosity reducer according to claim 5 or 6, characterized in that: The organic acid is selected from one or more of tall oil acid, stearic acid, lauric acid, capric acid, palmitic acid, rosin acid, dodecylbenzenesulfonic acid, behenic acid, linolenic acid and adipic acid.

8. The viscosity reducer according to claim 7, characterized in that The polyamine is selected from one or more of polyethylene polyamine, diethylene triamine, triethylene tetramine and tetraethylene pentamine.

9. A method for preparing the viscosity reducer according to any one of claims 1 to 8, characterized in that: The viscosity reducing agent is prepared by mixing the non-polar component A, the polar component B and the surfactant C.

10. A method for preparing the viscosity reducer according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: mixing a non-polar component A, a polar component B and a surfactant C, heating to 80-100 DEG C, stirring, keeping the temperature for 1-2 hours, and cooling to room temperature to obtain a viscosity reducing agent.

11. Use of the viscosity reducer according to any one of claims 1 to 8 or the viscosity reducer prepared by the preparation method according to claim 9 or 10 in drilling fluid.

12. The use according to claim 11, characterized in that: The volume ratio of the viscosity reducer to the drilling fluid is 3% to 5%.

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