A method for preparing modified sulfonated phenolic resin for drilling fluids

Abstract

This invention belongs to the field of oilfield drilling technology, specifically relating to a method for preparing a modified sulfonated phenolic resin for drilling fluids. This modified sulfonated phenolic resin is prepared by free radical polymerization, chemically bonding functional monomers containing both sulfonic acid anions and quaternary ammonium cations into the phenolic resin structure. The quaternary ammonium cation groups adsorb negatively charged clay particles, while the adamantyl group can adsorb onto the hydrophobic regions of the clay particles through association. This dual adsorption mechanism of hydrogen bonding and electrostatic attraction allows the sulfonated phenolic resin to rapidly adsorb onto the clay surface. Furthermore, the abundant sulfonic acid anions form a dense solvation layer after hydration, which, when the phenolic resin rapidly adsorbs onto the clay surface, forms a dense coating, preventing contact between the clay and water, thus stabilizing the clay particles and forming a dense mud cake. This results in a phenolic resin with excellent filtration loss reduction properties.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil field drilling, and particularly relates to a preparation method of modified sulfonated phenolic resin for drilling fluid. BACKGROUND

[0002] With the continuous consumption of fossil energy, oil exploration and development gradually extend to deep wells, ultra-deep wells and complex formations, and drilling operations are facing severe challenges such as high temperature and high pressure, high salinity formation water, and wellbore instability. The traditional drilling fluid system is prone to problems such as loss control, rheological property degradation, and wall protection failure in extreme environments, resulting in increased non-productive time and rising drilling costs. Under this background, phenolic resin treatment agent has become a key material for solving the technical bottleneck of drilling fluid due to its unique molecular structure and functional characteristics.

[0003] Sulfonated phenolic resin is a typical representative of filtration reducers for oil fields in recent years. It mainly forms a thin, dense and solid filter cake by fine particles (clay, etc.) in the drilling fluid to reduce the filtration loss. The special structure of sulfonated phenolic resin enables it to have good mechanical strength and excellent filtration reduction effect, and also has the functions of anti-sloughing and viscosity control, so it has been widely studied and applied.

[0004] However, in conventional high-temperature deep well drilling fluid, the adsorption amount of sulfonated phenolic resin on clay in the drilling fluid is small, which leads to a large amount of sulfonated phenolic resin added in the drilling fluid, which greatly causes waste of drilling materials. Therefore, how to improve the adsorption amount of phenolic resin on clay and further improve the filtration reduction performance of phenolic resin has become a research hotspot. The invention patent with application number CN202010157386.2 discloses a bubble-free modified sulfonated phenolic resin for drilling fluid and a preparation method. By designing the structure, the prepared sulfonated phenolic resin has good salt resistance and filtration resistance, etc. Therefore, by preparing sulfonated phenolic resin with a special structure, the problems existing in the prior art can be solved. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a preparation method of modified sulfonated phenolic resin for drilling fluid.

[0006] In the first aspect of the present application, a preparation method of modified sulfonated phenolic resin for drilling fluid is provided, which comprises the following steps:

[0007] First step, modification of phenolic resin

[0008] Using N,N-dimethylacetamide as the reaction medium, under the action of tin catalyst, the phenolic resin is modified using a modification reagent, the modification temperature is controlled to be 60-80℃, and the time is controlled to be 4-6h, to obtain a phenolic resin intermediate;

[0009] The mass ratio of the modifying agent and the phenolic resin is 1:0.4-0.6;

[0010] Second step, polymerization modification

[0011] In a dimethyl sulfoxide medium, using an initiator, initiating in-situ polymerization of the functional monomer and the phenolic resin intermediate, controlling the polymerization temperature to be 75-85 DEG C, and the time to be 8-12h, obtaining the modified sulfonated phenolic resin;

[0012] The mass ratio of the functional monomer and the phenolic resin intermediate is 1:0.1-0.3.

[0013] It is to be noted that in the above technical solution, first, the phenolic resin is functionally modified to carry unsaturated alkenyl functional groups in the structure, and the phenolic resin intermediate is prepared, then under the action of an initiator, the functional monomer and the unsaturated alkenyl in the structure of the phenolic resin intermediate are initiated to undergo free radical polymerization reaction, and the modified sulfonated phenolic resin is prepared.

[0014] As a preferred technical solution of the present application, the tin catalyst is any one of octyl mercaptan tin, methyl mercaptan tin, dibutyl tin dilaurate or stannous octoate.

[0015] As a preferred technical solution of the present application, the modifying agent is 3-isopropyl-dimethyl benzyl isocyanate.

[0016] As a preferred technical solution of the present application, the initiator is at least one of azobisisobutyronitrile or azobisisoheptyl nitrile.

[0017] As a preferred technical solution of the present application, the preparation method of the functional monomer comprises the following steps:

[0018] Step one, the adamantanol derivative and tetrahydrofuran are added to a reaction kettle, nitrogen is introduced for protection, stirring is started, after uniform mixing, the catalyst and 2,3-epoxypropyltrimethylammonium chloride are added to the reaction kettle, after addition, the temperature is raised to 65-70 DEG C, after 4-8h of temperature maintaining and stirring, the solvent is evaporated and removed, the product is collected, and the quaternary ammonium adamantane is obtained;

[0019] Step two, the quaternary ammonium adamantane is added to an ethanol aqueous solution with a volume fraction of 70-80%, after addition, stirring is uniform, then the hydroxide is added to the formed uniform solution, then the temperature is raised to 50-60 DEG C, after 1-2h of stirring, the 4-bromo-1-butanesulfonic acid is continuously added, then the temperature is further raised to 65-75 DEG C, after 8-12h of temperature maintaining, the solvent is evaporated and removed, the product is collected, and the functional monomer is obtained after a purification treatment process.

[0020] As a preferred technical scheme of the present application, the adamantanol derivative is 3-hydroxy-1-adamantyl methacrylate.

[0021] As a preferred technical scheme of the present application, the catalyst is boron trifluoride etherate.

[0022] As a preferred technical scheme of the present application, the molar ratio of the adamantanol derivative and 2,3-epoxypropyl trimethyl ammonium chloride is 1:1.

[0023] As a preferred technical scheme of the present application, the hydroxide is sodium hydroxide.

[0024] As a preferred technical scheme of the present application, the molar ratio of the quaternary ammonium adamantane and 4-bromo-1-butanesulfonic acid is 1:1.

[0025] It should be noted that, under the action of the catalyst, the hydroxyl substituent in the structure of the adamantanol derivative can undergo ring-opening addition with the epoxy group in the structure of 2,3-epoxypropyl trimethyl ammonium chloride to produce quaternary ammonium adamantane, and then, under the catalytic action of the hydroxide, the active hydroxyl group produced by the ring-opening addition reaction can further undergo substitution reaction with the halogen substituent in the structure of 4-bromo-1-butanesulfonic acid, thereby producing an adamantane derivative containing both sulfonic acid anion and quaternary ammonium cation in the structure, i.e. a functional monomer.

[0026] Compared with the prior art, the present application has the following beneficial effects:

[0027] The functional monomer containing both sulfonic acid anion and quaternary ammonium cation in the structure is chemically bonded in the structure of the phenolic resin by means of free radical polymerization, and when the sulfonated phenolic resin molecule exists in the mud, it can adsorb negatively charged clay particles through the quaternary ammonium cation group in its own structure, and the adamantane group with high hydrophobicity can be adsorbed on the hydrophobic region of the clay particles through association, which can effectively enhance the adsorption capacity of the phenolic resin and clay, so that the sulfonated phenolic resin can be quickly adsorbed on the surface of the clay to form a dense coating, thereby preventing the clay from contacting with water and realizing the stability of the clay particles, so that a dense mud cake can be formed, and the prepared phenolic resin has good filtration reduction performance. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical schemes of the embodiments of the present application, the drawings needed for the description of the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0029] Figure 1 Test chart for infrared analysis of the functional monomer. DETAILED DESCRIPTION

[0030] For the purpose of understanding the present application, the present application is illustrated by the following examples. It will be apparent to those skilled in the art that the examples are merely illustrative of the present application and should not be viewed as limiting the present application.

[0031] Example 1

[0032] The present example provides a preparation method of a modified sulfonated phenolic resin for drilling fluid, comprising the following steps:

[0033] First step, modification of phenolic resin

[0034] 3.5 g of phenolic resin is added to N,N-dimethylacetamide, and after mechanical stirring and uniform mixing, 1.8 g of 3-isopropyl-dimethylbenzyl isocyanate and 0.1 g of octyl mercaptan tin are added to the formed mixture, then the temperature is raised to 70℃, and after 6h of incubation and stirring, the solvent is evaporated, and the product is discharged after cooling, to obtain a phenolic resin intermediate;

[0035] Second step, polymerization modification

[0036] 2.6 g of phenolic resin intermediate is added to dimethyl sulfoxide, and stirred to form a uniform solution, then 0.5 g of functional monomer and 0.01 g of azobisisobutyronitrile are added to the uniform solution, after the addition is completed, the temperature is raised to 80℃, and after 8h of incubation and polymerization, the heating is stopped, the product is discharged after cooling, and the modified sulfonated phenolic resin is obtained.

[0037] The functional monomer is prepared by the following method:

[0038] Step one, 0.9 g of 3-hydroxy-1-adamantyl methacrylate and tetrahydrofuran are added to a reaction kettle, nitrogen is introduced for protection, stirring is started, and after uniform mixing, 0.01 g of boron trifluoride etherate complex and 0.58 g of 2,3-epoxypropyltrimethylammonium chloride are added to the reaction kettle, after the addition is completed, the temperature is raised to 70℃, and after 6h of incubation and stirring, the solvent is evaporated, and the product is collected to obtain a quaternary ammonium adamantane;

[0039] Step two, 0.8 g of quaternary ammonium adamantane is added to an aqueous solution of ethanol with a volume fraction of 70%, after the addition is completed, the mixture is stirred until uniform, then 0.3 g of sodium hydroxide is added to the formed uniform solution, and then the temperature is raised to 55℃, and after 2h of stirring, 0.45 g of 4-bromo-1-butanesulfonic acid is added, and then the temperature is further raised to 70℃, and after 9h of incubation, the solvent is evaporated, and the product is collected, and after purification treatment, the functional monomer is obtained.

[0040] Figure 1 The infrared analysis test chart of the functional monomer, wherein the characteristic absorption peak at 3203 cm -1 The characteristic absorption peak at 3056 cm -1 The characteristic absorption peak at 1746 cm -1 The characteristic absorption peak at 1482 cm -1 The characteristic absorption peak at 1180 cm -1 The characteristic absorption peak at 1052 cm -1 The characteristic absorption peak at 1052 cm

[0041] Example 2

[0042] The embodiment provides a preparation method of a modified sulfonated phenolic resin for a drilling fluid, and comprises the following steps:

[0043] Step 1, modification of the phenolic resin

[0044] 3.5g of the phenolic resin is added into N,N-dimethylacetamide, and after uniform mixing through mechanical stirring, 1.8g of 3-isopropyl-dimethylbenzyl isocyanate and 0.1g of dibutyltin dilaurate are added into the formed mixture, then the temperature is increased to 70 DEG C, and after 6h of incubation and stirring, the solvent is removed through evaporation, and the product is discharged after cooling, to obtain a phenolic resin intermediate;

[0045] Step 2, polymerization modification

[0046] 2.6g of the phenolic resin intermediate is added into dimethyl sulfoxide, and after stirring to form a uniform solution, 0.5g of the functional monomer and 0.01g of azobisisobutyronitrile are added into the uniform solution, then after the addition is completed, the temperature is increased to 80 DEG C, and after 8h of incubation and polymerization, heating is stopped, the product is discharged after cooling, and the modified sulfonated phenolic resin is collected.

[0047] The preparation method of the functional monomer is the same as that in the embodiment 1.

[0048] Example 3

[0049] The embodiment provides a preparation method of a modified sulfonated phenolic resin for a drilling fluid, and comprises the following steps:

[0050] Step 1, modification of the phenolic resin

[0051] 3.5g of phenolic resin is added into N,N-dimethylacetamide, and after being uniformly mixed by mechanical stirring, 1.8g of 3-isopropyl-dimethylbenzyl isocyanate and 0.1g of stannous octoate are added into the formed mixture, then the temperature is increased to 70 DEG C, and after being kept at 70 DEG C for 6h, the solvent is removed by evaporation, and the product is discharged after being cooled, to obtain a phenolic resin intermediate;

[0052] Second step, polymerization modification

[0053] 2.6g of the phenolic resin intermediate is added into dimethyl sulfoxide, and after being stirred to form a uniform solution, 0.5g of a functional monomer and 0.01g of azobisisheptyl nitrile are added into the uniform solution, then the temperature is increased to 80 DEG C, and after being kept at 80 DEG C for 8h, the heating is stopped, the product is discharged after being cooled, and the product is collected, to obtain a modified sulfonated phenolic resin.

[0054] The preparation method of the functional monomer is the same as that in Embodiment 1.

[0055] The modified sulfonated phenolic resin provided in the above embodiments is subjected to performance testing, and the testing method is as follows:

[0056] 0.5g of anhydrous sodium carbonate and 6.8g of bentonite are added into 350mL of deionized water, and after being added, the mixture is uniformly stirred, and after being maintained at room temperature for one day, 10g of sulfonated lignite and 10.5g of the modified sulfonated phenolic resin are continuously added, and after being added, the mixture is uniformly stirred, and then 102g of sodium chloride is added, and after being completely dissolved by stirring, the mixture is maintained at room temperature for 3h, and then the mixture is transferred into a temperature environment of 220 DEG C, and after being hot-rolled for 16h, the mixture is taken out, and naturally cooled to room temperature, and then 6g of anhydrous sodium carbonate is continuously added, and the mixture is uniformly stirred, to form a sample to be tested, and according to the standard GB / T 16783.1-2014, the filtration loss is tested under the testing conditions of 25 DEG C, 0.7MPa and 180 DEG C, 3.5MPa, respectively, and the filtration loss under normal temperature and pressure and the filtration loss under high temperature and high pressure are recorded.

[0057] The performance test data are shown in Table 1.

[0058] Table 1: Performance test results

[0059]

[0060] The commercially available sulfonated phenolic resin is SMP-I type sulfonated phenolic resin.

[0061] As can be seen from the above, the sulfonated phenolic resin prepared in the embodiments has high temperature resistance, and the filtration loss reduction effect is excellent. The commercially available sulfonated phenolic resin does not contain quaternary ammonium cations and adamantane rigid rings in the structure, so that the adsorption effect of the prepared sulfonated phenolic resin with clay is general, and the rigidity is reduced, and therefore the comprehensive performance is poor.

[0062] The principles and implementations of the present application are described in the specific examples, the above examples are only used to help understand the method of the present application and its core idea, including the best mode, and also enable any person skilled in the art to practice the present application, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for ordinary skilled in the art, without departing from the principles of the present application, some improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of the present application.

Claims

1. A method for preparing a modified sulfonated phenol-formaldehyde resin for use in drilling fluids, characterized by, The method comprises the following steps: The first step, phenolic resin modification In the presence of a tin catalyst, the phenolic resin is modified by using a modifying agent in N,N-dimethylacetamide as a reaction medium, the modification temperature is controlled at 60-80℃, and the time is controlled at 4-6h, to obtain a phenolic resin intermediate; The mass ratio of the modifying agent to the phenolic resin is 1:0.4-0.6; The second step, polymerization modification In the presence of a dimethyl sulfoxide medium, the functional monomer is in-situ polymerized with the phenolic resin intermediate by using an initiator, the polymerization temperature is controlled at 75-85℃, and the time is controlled at 8-12h, to obtain a modified sulfonated phenolic resin; The modified sulfonated phenolic resin is prepared by using a functional monomer containing a sulfonic acid group in the structure and a phenolic resin containing an unsaturated alkenyl functional group in the structure through free radical polymerization; The mass ratio of the functional monomer to the phenolic resin intermediate is 1:0.1-0.3; The tin catalyst is any one of octyl mercaptan tin, methyl mercaptan tin, dibutyl tin dilaurate or stannous octoate; The modifying agent is 3-isopropyl-dimethyl benzyl isocyanate; The initiator is at least one of azobisisobutyronitrile or azobisisoheptyl nitrile; The preparation method of the functional monomer comprises the following steps: Step one, a derivative of adamantanol and tetrahydrofuran are added to a reaction kettle, nitrogen is introduced for protection, stirring is started, and after uniform mixing, a catalyst and 2,3-epoxypropyltrimethylammonium chloride are added to the reaction kettle, after addition, the temperature is raised to 65-70℃, and after 4-8h of heat preservation and stirring, the solvent is evaporated to remove, and the product is collected to obtain a quaternary ammonium adamantane; Step two, the quaternary ammonium adamantane is added to an ethanol aqueous solution with a volume fraction of 70-80%, after addition, stirring is uniform, then a hydroxide is added to the formed uniform solution, then the temperature is raised to 50-60℃, stirring is performed for 1-2h, then 4-bromo-1-butanesulfonic acid is further added, the temperature is further raised to 65-75℃, heat preservation is performed for 8-12h, then the solvent is evaporated to remove, and the product is collected, and after a purification treatment process, the functional monomer is obtained; The derivative of adamantanol is 3-hydroxy-1-adamantyl methacrylate; The catalyst is boron trifluoride etherate complex.

2. The method for preparing a modified sulfonated phenolic resin for drilling fluid according to claim 1, characterized in that, The molar ratio of the derivative of adamantanol to 2,3-epoxypropyltrimethylammonium chloride is 1:

1.

3. The method for preparing a modified sulfonated phenolic resin for drilling fluid according to claim 1, characterized in that, The hydroxide is sodium hydroxide.

4. The method for preparing a modified sulfonated phenolic resin for drilling fluid according to claim 1, characterized in that, The molar ratio of the quaternary ammonium adamantane to 4-bromo-1-butanesulfonic acid is 1:1.

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