An oil-based fluid loss additive, its preparation method and its use in drilling fluids

Abstract

This application provides an oil-based cutting agent, obtained by reacting a polybasic acid sequentially with an amino compound A, an amino compound B, an amino compound C, and a long-chain alkyl acid, followed by dilution. The amino compound A is an alkenyl polyamine; the amino compound B is an alkyl diamine; and the amino compound C is an alkyl alcoholamine. This application also provides a method for preparing the oil-based cutting agent and a drilling fluid. This application involves sequentially reacting an alkenyl polyamine, an alkyl diamine, and an alkyl alcoholamine with a polybasic acid, followed by chain extension with a long-chain alkyl acid, and finally dilution to obtain an oil-based cutting agent that can effectively improve the shear force of oil-based drilling fluids, has minimal impact on the viscosity of the drilling fluid system, improves the flow pattern, enhances the rock-carrying capacity and barite suspension stability of oil-based drilling fluids, and is more beneficial for field operations.

Description

Technical Field

[0001] This invention relates to the field of synthetic agents for oilfield drilling fluids, and particularly to an oil-based cutting agent, its preparation method, and its application in drilling fluids. Background Technology

[0002] In drilling complex formations such as those with high water sensitivity, fractured zones, and shale gas horizontal wells, the dispersive effect of water on clay makes conventional water-based drilling fluid systems prone to clay hydration and dispersion, leading to wellbore instability and impacting downhole safety. In contrast, oil-based drilling fluids, with diesel (or white oil) as the continuous phase, do not cause clay hydration and dispersion, resulting in better wellbore stability in complex formations and better lubrication, thus benefiting reservoir protection. Currently, oil-based drilling fluids have become the preferred system for drilling in various complex formations. However, compared to water-based drilling fluids, oil-based drilling fluids have weaker system stability, lower shear stress, and weaker rock-carrying capacity, especially under high-density conditions, making them prone to barite settling. To ensure the suspension stability of oil-based drilling fluids, shear-lifting agents must be added to increase the shear stress, improve the flow pattern, and enhance the system's suspension stability.

[0003] Currently, commonly used oil-based cutting agents are mainly organo-soil modifiers and polyamide compounds. For example, patent application 201710234741X discloses an organo-soil cutting agent, which is used in large quantities in oil-based drilling fluids but has limited cutting effect; patent application 201610967005.0 discloses a polyamide cutting agent, but this cutting agent only has a cutting effect at relatively large dosages and is relatively expensive. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide an oil-based shearing agent, its preparation method and its application in drilling fluid. The oil-based shearing agent provided by this application can effectively improve the shear force of oil-based drilling fluid at a low dosage, has little impact on the viscosity of the drilling fluid system, can improve the flow pattern, enhance the rock-carrying capacity and barite suspension stability of oil-based drilling fluid, and is more conducive to on-site construction.

[0005] This application provides an oil-based cutting agent, which is obtained by reacting a polybasic acid sequentially with an amino compound A, an amino compound B, an amino compound C, and a long-chain alkyl acid, followed by dilution.

[0006] The amine compound A is an alkenyl polyamine;

[0007] The amino compound B is an alkyl diamine;

[0008] The amine compound C is an alkyl alcoholamine.

[0009] In some specific implementations, the amine compound A is selected from one or more of diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, pentaethylenehexamine, and hexaethyleneheptaamine;

[0010] The amino compound B is selected from one or more of N,N-dimethylethylenediamine, N,N-dimethylpropylenediamine, N,N-dimethylbutyldiamine, N,N-diethylethylenediamine, N,N-dibutylethylenediamine, N,N-ditert-butylethylenediamine, and N,N-diethylpropylenediamine;

[0011] The amine compound C is selected from one or more of ethanolamine, diethanolamine, and triethanolamine.

[0012] In some specific implementations, the polybasic acid is a dimer acid;

[0013] The long-chain alkyl acid is selected from one or more of oleic acid and dodecylbenzenesulfonic acid.

[0014] In some specific implementations, the molar ratio of the polybasic acid, amino compound A, amino compound B, amino compound C and long-chain alkyl acid is 1:0.1~0.5:0.1~0.8:0.1~0.8:0.1~0.3.

[0015] In some specific implementations, the diluent used for dilution is white oil and triethylene glycol monobutyl ether in a volume ratio of 2:1.

[0016] In some specific implementations, the amount of the diluent used is 10 wt% to 30 wt% of the reaction product.

[0017] This application also provides a method for preparing the oil-based cutting agent described in the above technical solution, including the following steps:

[0018] A polybasic acid and amino compound A undergo a first reaction, followed by the addition of amino compounds B and C for a second reaction, and then the addition of a long-chain alkyl acid for a third reaction. The resulting reaction product is diluted to obtain a cutting agent for oil-based drilling fluids.

[0019] In some specific implementations, the temperature of the first reaction is 120℃~180℃, and the time is 1~3h;

[0020] The second reaction was carried out at a temperature of 120℃ to 180℃ for 1 to 3 hours.

[0021] The temperature for the third reaction is 120℃~180℃, and the reaction time is 0.5~1h.

[0022] In some specific implementations, the obtained reaction product is cooled to 80–100°C and then diluted.

[0023] This application provides a drilling fluid, including the oil-based cutting agent described in the above technical solution or the oil-based cutting agent prepared by the above technical solution.

[0024] The oil-based cutting agent provided in this application is obtained by reacting a polybasic acid sequentially with amino compounds A, B, and C, and then diluting the mixture. Specifically, amino compound A is an alkenyl polyamine; amino compound B is an alkyl diamine; and amino compound C is an alkyl alcoholamine. This application sequentially reacts an alkenyl polyamine, an alkyl diamine, and an alkyl alcoholamine with a polybasic acid, followed by chain extension with a long-chain alkyl acid. The resulting oil-based cutting agent, after dilution, effectively improves the shear force of oil-based drilling fluids, has minimal impact on the viscosity of the drilling fluid system, improves the flow pattern, enhances the rock-carrying capacity and barite suspension stability of oil-based drilling fluids, and is more conducive to field operations. Furthermore, the oil-based cutting agent provided in this application has a long maintenance cycle, significantly improves the rheology and barite suspension stability of oil-based drilling fluids under high-temperature conditions, effectively solves problems such as barite settling and poor rock-carrying capacity in high-density oil-based drilling fluids, and has a simple production process, minimizing the risk of excessive gelation due to raw material condensation reactions during production, thus facilitating industrial production. Detailed Implementation

[0025] This invention provides an oil-based cutting agent, its preparation method, and its application in drilling fluids. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments. Those skilled in the art can clearly modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0026] This application provides an oil-based cutting agent, which is obtained by reacting a polybasic acid sequentially with an amino compound A, an amino compound B, an amino compound C, and a long-chain alkyl acid, followed by dilution.

[0027] The amine compound A is an alkenyl polyamine;

[0028] The amino compound B is an alkyl diamine;

[0029] The amine compound C is an alkyl alcoholamine.

[0030] This application sequentially reacts alkenyl polyamines, alkyl diamines, and alkyl alcoholamines with polybasic acids, then extends the chain using long-chain alkyl acids, and finally dilutes the resulting oil-based shearing agent to effectively improve the shear force of oil-based drilling fluids, has little impact on the viscosity of the drilling fluid system, improves the flow pattern, enhances the rock-carrying capacity and barite suspension stability of oil-based drilling fluids, and is more conducive to on-site construction.

[0031] This application also provides a method for preparing the oil-based cutting agent described in the above technical solution, including the following steps:

[0032] A polybasic acid and amino compound A undergo a first reaction, followed by the addition of amino compounds B and C for a second reaction, and then the addition of a long-chain alkyl acid for a third reaction. The resulting reaction product is diluted to obtain a cutting agent for oil-based drilling fluids.

[0033] This application uses polybasic acids, amino compounds A, B, and C, and long-chain alkyl acids as raw materials. The polybasic acid is preferably a dimer acid. This application does not have special restrictions on the source of the dimer acid; it can be purchased directly. In some specific implementations, amino compound A is an alkenyl polyamine, including but not limited to diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and hexaethyleneheptamine, and can be one or more of these. When the alkenyl polyamine is a combination of two or more substances, this application does not have special restrictions on the specific proportions of each substance. In some specific implementations, the amino compound B is an alkyl diamine, including but not limited to N,N-dimethylethylenediamine, N,N-dimethylpropylenediamine, N,N-dimethylbutanediamine, N,N-diethylethylenediamine, N,N-dibutylethylenediamine, N,N-di-tert-butylethylenediamine, and N,N-diethylpropylenediamine, etc., and may be one or more of these. When amino compound B is a combination of multiple substances, this application does not impose any special restrictions on the specific proportions of each substance. In some specific implementations, the amino compound C is an alkyl alcoholamine, including but not limited to ethanolamine, diethanolamine, and triethanolamine, etc., and may be one or more of these. When amino compound C is a combination of multiple substances, this application does not impose any special restrictions on the specific proportions of each substance. In some specific implementations, the long-chain alkyl acid includes but is not limited to oleic acid and dodecylbenzenesulfonic acid, etc., and may be one or more of these. When the long-chain alkyl acid is a combination of multiple substances, this application does not impose any special restrictions on the specific proportions of each substance.

[0034] In some specific implementations, the molar ratio of the polybasic acid, amino compound A, amino compound B, amino compound C and long-chain alkyl acid is 1:0.1-0.5:0.1-0.8:0.1-0.8:0.1-0.3, preferably 1:0.2-0.4:0.2-0.6:0.2-0.6:0.15-0.25.

[0035] Specifically, this application first mixes a polybasic acid and an amino compound A to carry out a first reaction. In some specific implementations, the first reaction is preferably carried out under stirring conditions. In some specific implementations, the temperature of the first reaction is preferably 120°C to 180°C, more preferably 130°C to 170°C, and the time is preferably 1 to 3 hours, more preferably 1.5 hours to 2.5 hours.

[0036] After the first reaction is completed, amino compound B and amino compound C are added to the obtained reaction mixture to carry out a second reaction. In some specific implementations, the reaction is preferably carried out under stirring conditions. In some specific implementations, the temperature of the second reaction is preferably 120℃~180℃, more preferably 130℃~170℃, and the time is preferably 1~3h, more preferably 1.5h~2.5h.

[0037] After the second reaction is completed, a long-chain alkyl acid is added to the obtained reaction mixture for a third reaction. In some specific implementations, the third reaction is preferably carried out under stirring conditions. In some specific implementations, the temperature of the third reaction is preferably 120℃~180℃, more preferably 130℃~170℃, and the time is preferably 0.5~1h, more preferably 1h.

[0038] After the reaction is complete, the resulting reaction product is cooled and diluted to obtain a cutting agent for oil-based drilling fluids. In some specific implementations, it is preferable to cool the resulting reaction product to 80–100°C for dilution, more preferably to 85–95°C. In some specific implementations, the diluent used for dilution is white oil and triethylene glycol monobutyl ether in a volume ratio of 2:1. In some specific implementations, the amount of the diluent used is 10 wt%–30 wt% of the reaction product, preferably 15 wt%–25 wt%. After dilution, the resulting product is cooled to room temperature to obtain the cutting agent for oil-based drilling fluids.

[0039] This application provides a drilling fluid, including the oil-based cutting agent described in the above technical solution or the oil-based cutting agent prepared by the above technical solution.

[0040] The drilling fluid provided in this application is an oil-based drilling fluid, including a base slurry and the oil-based cutting agent described in the above technical solution or the oil-based cutting agent prepared by the above technical solution.

[0041] In some specific implementations, the base slurry comprises: diesel oil, calcium chloride solution, emulsifier, organolithic soil, oxidized asphalt, calcium oxide, and barite. In some specific implementations, the concentration of the calcium chloride solution is preferably 20wt%–30wt%, more preferably 25wt%. In some specific implementations, the ratio of diesel oil, calcium chloride solution, emulsifier, organolithic soil, oxidized asphalt, and calcium oxide is preferably 300–350mL:70–90mL:15–25g:12–16g:8–12g:6–10g, more preferably 320mL:80mL:20g:14g:10g:8g. In some specific implementations, the amount of barite used is preferably to increase the drilling fluid density to 1.4–1.8 g / cm³. 3 More preferably 1.6 g / cm³ 3 This application does not impose any special restrictions on the types of diesel oil, emulsifiers, organocarbons, and oxidized asphalt mentioned; any specific substances commonly used in the art may be used.

[0042] In some specific implementations, the ratio of the oil-based cutting agent to the diesel fuel is 0.5–3 g: 320 mL, preferably 1–2.5 g: 320 mL.

[0043] The oil-based cutting agent provided in this application is obtained by reacting a polybasic acid sequentially with amino compounds A, B, and C, and then diluting the mixture. Specifically, amino compound A is an alkenyl polyamine; amino compound B is an alkyl diamine; and amino compound C is an alkyl alcoholamine. This application sequentially reacts an alkenyl polyamine, an alkyl diamine, and an alkyl alcoholamine with a polybasic acid, followed by chain extension with a long-chain alkyl acid. The resulting oil-based cutting agent, after dilution, effectively improves the shear force of oil-based drilling fluids, has minimal impact on the viscosity of the drilling fluid system, improves the flow pattern, enhances the rock-carrying capacity and barite suspension stability of oil-based drilling fluids, and is more conducive to field operations. Furthermore, the oil-based cutting agent provided in this application has a long maintenance cycle, significantly improves the rheology and barite suspension stability of oil-based drilling fluids under high-temperature conditions, effectively solves problems such as barite settling and poor rock-carrying capacity in high-density oil-based drilling fluids, and has a simple production process, minimizing the risk of excessive gelation due to raw material condensation reactions during production, thus facilitating industrial production.

[0044] The following examples further illustrate the oil-based cutting agent provided in this application, its preparation method, and its application in drilling fluids.

[0045] In the following embodiments, dimeric acid was purchased from Liancheng Baixin Technology Co., Ltd.

[0046] Example 1

[0047] 1 mol of dimer acid (polyacid) and 0.5 mol of triethylenetetramine (amine compound A) were added to a reactor and heated to 150°C for 2 h under stirring. Then, 0.1 mol of di-tert-butylethylenediamine (amine compound B) and 0.3 mol of ethanolamine (amine compound C) were added to the reactor and the reaction was continued for 3 h. Finally, 0.2 mol of oleic acid (long-chain alkyl acid) was added and the reaction was carried out for 1 h. The temperature was then lowered to 80°C, and a 15% (w / w) diluent was mixed in. The mixture was then cooled to room temperature to obtain a cutting agent sample for oil-based drilling fluid.

[0048] Example 2

[0049] 1 mol of dimer acid and 0.1 mol of hexaethyleneheptaamine were added to the reactor and heated to 120°C for 3 h under stirring. Then, 0.8 mol of N,N-dimethylethylenediamine and 0.6 mol of diethanolamine were added to the reactor and the reaction continued for 2 h. Finally, 0.1 mol of oleic acid was added and the reaction was carried out for 0.8 h. The temperature was lowered to 100°C, and a 30% (w / w) diluent was mixed in. The mixture was then cooled to room temperature to obtain a sample of cutting agent for oil-based drilling fluid.

[0050] Example 3

[0051] 1 mol of dimer acid and 0.3 mol of tetraethylenepentamine were added to the reactor and heated to 180°C for 1 h under stirring. Then, 0.4 mol of N,N-dimethylpropylenediamine and 0.1 mol of triethanolamine were added to the reactor and the reaction was continued for 1 h. Finally, 0.2 mol of dodecylbenzenesulfonic acid was added and the reaction was carried out for 0.5 h. The temperature was then lowered to 90°C, and a 10% (w / w) diluent was mixed in. The mixture was then cooled to room temperature to obtain a cutting agent sample for oil-based drilling fluid.

[0052] Examples 4-7

[0053] The steps are the same as in Example 1, and the reactants and their amounts are shown in Table 1:

[0054] Table 1. Reactive substances and amounts

[0055]

[0056] Comparative Examples 1-2

[0057] The steps are the same as in Example 1, and the reactants and their amounts are shown in Table 2:

[0058] Table 2. Reactive substances and amounts

[0059]

[0060] The oil-based cutting agents synthesized in Examples 1-7 and Comparative Examples 1-2 were added to oil-based drilling fluid slurries for performance evaluation.

[0061] Oil-based drilling fluid slurry formulation: 320mL diesel oil + 80mL CaCl2 solution (25% concentration) + 20g emulsifier (LEMUL emulsifier produced by Zhongyuan Petroleum Engineering Company and commercially available) + 14g organic clay + 10g oxidized asphalt + 8g CaO, barite weighted to 1.6g / cm³. 3 Prepare 10 samples according to the above formula for later use.

[0062] One sample was used as a blank sample, and 1.2g of the oil-based shearing agent prepared in Examples 1-7 and Comparative Examples 1-2 was added to the other 9 samples respectively. The samples were then subjected to rolling aging at 180℃ for 16 hours, and performance tests were conducted. The results are shown in Table 3. Table 3 shows that the synthesized oil-based shearing agent significantly improved the dynamic shear force (YP) and dynamic-plastic ratio (YP / PV) of the drilling fluid, effectively improving the suspension stability of barite in the oil-based drilling fluid.

[0063] Table 3. Effects of oil-based cutting agents on the properties of oil-based drilling fluids

[0064]

[0065] 1.2g of the sample from Example 4 was added to the oil-based drilling fluid slurry and aged at 180℃ for 72 hours. Performance tests were then conducted, and the results are shown in Table 4. Table 4 shows that after aging at 180℃ for 72 hours, the rheological properties and demulsification voltage of the drilling fluid in the sample from Example 4 remained relatively stable, indicating that the oil-based shearing agent has good temperature resistance and can still significantly improve the shear force of the oil-based drilling fluid and enhance the suspension stability of barite under prolonged high-temperature aging conditions.

[0066] Table 4. Effects of oil-based cutting agents on the properties of oil-based drilling fluids

[0067]

[0068] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An oil-based cutting agent, obtained by reacting a polybasic acid sequentially with an amino compound A, an amino compound B, an amino compound C, and a long-chain alkyl acid, followed by dilution; The amine compound A is an alkenyl polyamine; The amino compound B is an alkyl diamine; The amine compound C is an alkyl alcoholamine.

2. The oil-based debonder of claim 1, wherein, The amine compound A is selected from one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and hexaethyleneheptamine; The amino compound B is selected from one or more of N,N-dimethylethylenediamine, N,N-dimethylpropylenediamine, N,N-dimethylbutyldiamine, N,N-diethylethylenediamine, N,N-dibutylethylenediamine, N,N-ditert-butylethylenediamine, and N,N-diethylpropylenediamine; The amine compound C is selected from one or more of ethanolamine, diethanolamine, and triethanolamine.

3. The organic cutting agent according to claim 1, characterized in that, The polyacid is a dimer acid; The long-chain alkyl acid is selected from one or more of oleic acid and dodecylbenzenesulfonic acid.

4. The oil-based cutting agent according to any one of claims 1 to 3, characterized in that, The molar ratio of the polybasic acid, amino compound A, amino compound B, amino compound C and long-chain alkyl acid is 1:0.1-0.5:0.1-0.8:0.1-0.8:0.1-0.

3.

5. The oil-based cutting agent according to claim 4, characterized in that, The diluent used for the dilution is white oil and triethylene glycol monobutyl ether in a volume ratio of 2:

1.

6. The oil-based cutting agent according to claim 5, characterized in that, The amount of the diluent used is 10 wt% to 30 wt% of the reaction product.

7. A method for preparing the oil-based cutting agent according to any one of claims 1 to 6, comprising the following steps: A polybasic acid and amino compound A undergo a first reaction, followed by the addition of amino compounds B and C for a second reaction, and then the addition of a long-chain alkyl acid for a third reaction. The resulting reaction product is diluted to obtain a cutting agent for oil-based drilling fluids.

8. The preparation method according to claim 7, characterized in that, The temperature of the first reaction is 120℃~180℃, and the time is 1~3h; The second reaction was carried out at a temperature of 120℃ to 180℃ for 1 to 3 hours. The temperature for the third reaction is 120℃~180℃, and the reaction time is 0.5~1h.

9. The preparation method according to claim 7, characterized in that, The obtained reaction product was cooled to 80-100℃ and then diluted.

10. A drilling fluid comprising the oil-based cutting agent according to any one of claims 1 to 6 or the oil-based cutting agent prepared by the method according to any one of claims 7 to 9.

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