A flow profile modifier for water-based drilling fluids, method of making and method of use

Abstract

This invention discloses a flow modifier for water-based drilling fluids, its preparation method, and its application method. The flow modifier comprises, by mass parts: 30-50 parts sodium carboxymethyl cellulose, 10-30 parts nano-lithium saponite, and 10-30 parts silane coupling agent. The flow modifier obtained by this invention enables the water-based drilling fluid to maintain stable rheological properties after aging at 150°C. Even after aging at 180°C or under conditions of 20% sodium chloride intrusion, the flow modifier still provides protection for the drilling fluid. The silane coupling agent undergoes hydrolysis to produce organosilicon alcohols, which then undergo condensation polymerization to form polysiloxane structures that are adsorbed onto the CMC molecular chains and interspersed within the polymer network structure, enhancing the polymer's thermal stability. The introduction of nano-lithium saponite (LAP) enhances the spatial network structure of the drilling fluid through hydrogen bonding and electrostatic adsorption, maintaining good dispersion performance of bentonite particles, improving the rheological properties of the drilling fluid, and increasing its ability to suspend cuttings and clean the wellbore.

Description

Technical Field

[0001] This invention relates to the field of flow pattern regulators, specifically to a flow pattern regulator for water-based drilling fluids, its preparation method, and its application method. Background Technology

[0002] Flow modifiers, as crucial treatment agents in constructing water-based drilling fluid systems, significantly impact cuttings removal, wellbore cleaning, and wellbore stability. With the ongoing drilling of numerous wells exceeding 10,000 meters in depth in my country, commonly used flow modifiers still face challenges. Increased temperature easily leads to polymer degradation, causing main chain or branch chain breakage, reducing molecular weight, and losing polymeric properties, thus damaging drilling fluid performance. Commonly used acrylamide polymers degrade at high temperatures, releasing acrylamide monomers, posing significant harm to the formation environment and human health. Xanthan gum and starch begin to degrade above 120°C and completely degrade and become ineffective above 150°C. This results in uncontrolled rheological properties of the drilling fluid, potentially leading to complex downhole accidents such as stuck pipe, wellbore instability, and circulation loss. Summary of the Invention

[0003] This invention addresses the problems existing in the prior art by providing a flow pattern modifier for water-based drilling fluids, its preparation method, and its application method.

[0004] The technical solution adopted in this invention is: a flow pattern modifier for water-based drilling fluids, comprising, by mass parts:

[0005] Sodium carboxymethyl cellulose 30-50 parts, nano lithium saponite 10-30 parts, silane coupling agent 10-30 parts.

[0006] Furthermore, the silane coupling agent is one of γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, and γ-glycidoxypropyltrimethoxysilane.

[0007] Furthermore, based on parts by weight, it includes:

[0008] Sodium carboxymethyl cellulose 30-40 parts, nano lithium saponite 10-20 parts, silane coupling agent 10-20 parts.

[0009] Furthermore, by weight, it includes: 40 parts sodium carboxymethyl cellulose, 10 parts nano lithium saponite, and 20 parts silane coupling agent.

[0010] Furthermore, by weight, it includes: 30 parts sodium carboxymethyl cellulose, 10 parts nano lithium saponite, and 20 parts silane coupling agent.

[0011] Furthermore, by weight, it includes: 30 parts sodium carboxymethyl cellulose, 10 parts nano lithium saponite, and 10 parts silane coupling agent.

[0012] A method for preparing a flow pattern modifier for water-based drilling fluids includes the following steps:

[0013] Step 1: Add nano lithium soapstone to the solvent and mix thoroughly;

[0014] Step 2: Slowly add sodium carboxymethyl cellulose to the solution obtained in Step 1 and mix thoroughly.

[0015] Step 3: Add silane coupling agent dropwise to the solution obtained in step 2, reflux the reaction, and then wash, dry, and pulverize to obtain the desired flow pattern regulator.

[0016] Furthermore, the reflux reaction time in step 3 is 3 to 15 hours.

[0017] Furthermore, in step 2, the solution obtained in step 1 is first heated to 40-80°C, and then sodium carboxymethyl cellulose is added.

[0018] A method for using a flow pattern modifier for water-based drilling fluids, comprising thoroughly mixing the drilling fluid, flow pattern modifier, bentonite, and sodium carbonate in the following proportions before use;

[0019] The drilling fluid, calculated per 450 mL, includes 0.9–6.75 g of flow pattern modifier, 18 g of bentonite, and 0.9 g of sodium carbonate.

[0020] The beneficial effects of this invention are:

[0021] (1) The flow pattern regulator obtained by the present invention can keep the rheological properties of water-based drilling fluid stable after aging at 150°C. After aging at 180°C or under the condition of 20% sodium chloride intrusion, the flow pattern regulator still plays a protective role for the drilling fluid.

[0022] (2) The silane coupling agent in this invention can undergo hydrolysis to produce organosilicon alcohol, and then undergo condensation polymerization to generate polysiloxane structure adsorbed on CMC molecular chain and interspersed in polymer network structure, which enhances the thermal stability of polymer.

[0023] (3) This invention introduces nano-lithium saponite LAP, which further enhances the spatial network structure of drilling fluid through hydrogen bonding and electrostatic adsorption, maintains the good dispersion performance of bentonite particles, enhances the rheological properties of drilling fluid, and improves the ability of drilling fluid to suspend rock cuttings and clean the wellbore. Attached Figure Description

[0024] Figure 1 The main reaction mechanism of the flow pattern regulator obtained in this invention is described.

[0025] Figure 2This is a microscopic morphology diagram of the flow pattern regulator obtained in Example 1 of the present invention.

[0026] Figure 3 The infrared spectrum of the flow pattern regulator obtained in Example 1 of this invention is shown. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] A flow pattern modifier for water-based drilling fluids, comprising, by weight parts:

[0029] The mixture comprises 30-50 parts sodium carboxymethyl cellulose, 10-30 parts nano-lithium saponite, and 10-30 parts silane coupling agent. Preferably, it comprises 30-40 parts sodium carboxymethyl cellulose, 10-20 parts nano-lithium saponite, and 10-20 parts silane coupling agent. The silane coupling agent is one of γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, and γ-glycidoxypropyltrimethoxysilane.

[0030] A method for preparing a flow pattern modifier for water-based drilling fluids includes the following steps:

[0031] Step 1: Add nano lithium soapstone to deionized water and stir in a beaker until the solution becomes clear and transparent. Then transfer the solution in the beaker to a three-necked flask.

[0032] Step 2: Heat the solution obtained in Step 1 to 40-80°C, and slowly add sodium carboxymethyl cellulose while stirring until completely dissolved.

[0033] Step 3: Add silane coupling agent dropwise to the solution obtained in step 2, reflux for 3 to 12 hours, then wash, dry, and pulverize to obtain the desired flow pattern regulator.

[0034] When used in water-based drilling fluids, the total volume of the drilling fluid is 450 mL, including 0.9–6.75 g of flow pattern modifier, 18 g of bentonite, and 0.9 g of sodium carbonate.

[0035] The present invention will be further described below with reference to specific embodiments.

[0036] Example 1

[0037] A method for preparing a flow pattern modifier for water-based drilling fluids includes the following steps:

[0038] Step 1: Add 1g of nano lithium soapstone (LAP) to a certain amount of deionized water and stir in a 250mL beaker for 10 minutes until the solution becomes clear and transparent. Then transfer the solution in the beaker to a three-necked flask.

[0039] Step 2: Heat the solution obtained in Step 1 to 70°C, slowly add 4g of sodium carboxymethyl cellulose (CMC), and stir for 1 hour until completely dissolved.

[0040] Step 3: Add 2g of γ-aminopropyltriethoxysilane to the solution obtained in Step 2, reflux for 5 hours, wash several times with acetone and ethanol, dry at 65℃ for 24 hours, and pulverize to obtain the desired flow pattern regulator.

[0041] Figure 2 This is a scanning electron microscope (SEM) schematic diagram of the flow pattern regulator obtained in this embodiment. As can be seen from the figure, it possesses a distinct and dense spatial network structure. These network structures can improve the shear force of the drilling fluid and play a decisive role in suspending drilling cuttings and cleaning the well bottom. The appearance of these network structures is mainly due to the large number of hydroxyl, carboxyl, and amino groups in the composite material. Through electrostatic attraction and hydrogen bonding adsorption, the molecular chains are tightly entangled, forming a strong and dense network structure.

[0042] Figure 3 This is the infrared spectrum of the flow pattern modifier obtained in this embodiment. In the figure, CMC is the flow pattern modifier obtained in Comparative Example 2, and CMC-LAP is the rheology modifier obtained in Example 1. The spectrum shows that the flow pattern is most effective in the 900–1200 cm⁻¹ range. -1 The peak range produces characteristic absorption peaks of β-1,4-glycosidic bond COC vibration and CO stretching, with a peak at 1620 cm⁻¹. -1 The nearby -COO absorption peaks are characteristic of sodium carboxymethyl cellulose. At 444 cm⁻¹... -1 The presence of characteristic absorption peaks for Si-C bonds indicates that the silane coupling agent was successfully introduced onto the surface of sodium carboxymethyl cellulose.

[0043] Example 2

[0044] A method for preparing a flow pattern modifier for water-based drilling fluids includes the following steps:

[0045] Step 1: Add 1g of nano lithium soapstone (LAP) to a certain amount of deionized water and stir in a 250mL beaker for 10 minutes until the solution becomes clear and transparent. Then transfer the solution in the beaker to a three-necked flask.

[0046] Step 2: Heat the solution obtained in Step 1 to 70°C, slowly add 3g of sodium carboxymethyl cellulose (CMC), and stir for 1 hour until completely dissolved.

[0047] Step 3: Add 2g of γ-aminopropyltriethoxysilane to the solution obtained in Step 2, reflux for 5 hours, wash several times with acetone and ethanol, dry at 65℃ for 24 hours, and pulverize to obtain the desired flow pattern regulator.

[0048] Example 3

[0049] A method for preparing a flow pattern modifier for water-based drilling fluids includes the following steps:

[0050] Step 1: Add 1g of nano lithium soapstone (LAP) to a certain amount of deionized water and stir in a 250mL beaker for 10 minutes until the solution becomes clear and transparent. Then transfer the solution in the beaker to a three-necked flask.

[0051] Step 2: Heat the solution obtained in Step 1 to 70°C, slowly add 3g of sodium carboxymethyl cellulose (CMC), and stir for 1 hour until completely dissolved.

[0052] Step 3: Add 1g of γ-aminopropyltriethoxysilane to the solution obtained in Step 2, reflux for 5 hours, wash several times with acetone and ethanol, dry at 65℃ for 24 hours, and pulverize to obtain the desired flow pattern regulator.

[0053] Example 4

[0054] A method for preparing a flow pattern modifier for water-based drilling fluids includes the following steps:

[0055] Step 1: Add 1g of nano lithium soapstone (LAP) to a certain amount of deionized water and stir in a 250mL beaker for 10 minutes until the solution becomes clear and transparent. Then transfer the solution in the beaker to a three-necked flask.

[0056] Step 2: Heat the solution obtained in Step 1 to 70°C, slowly add 3g of sodium carboxymethyl cellulose (CMC), and stir for 1 hour until completely dissolved.

[0057] Step 3: Add 1g of N-(β-aminoethyl)-γ-aminopropyltriethoxysilane to the solution obtained in step 2, reflux for 5 hours, wash several times with acetone and ethanol, dry at 65°C for 24 hours, and pulverize to obtain the desired flow pattern regulator.

[0058] Example 5

[0059] A method for preparing a flow pattern modifier for water-based drilling fluids includes the following steps:

[0060] Step 1: Add 1g of nano lithium soapstone (LAP) to a certain amount of deionized water and stir in a 250mL beaker for 10 minutes until the solution becomes clear and transparent. Then transfer the solution in the beaker to a three-necked flask.

[0061] Step 2: Heat the solution obtained in Step 1 to 70°C, slowly add 3g of sodium carboxymethyl cellulose (CMC), and stir for 1 hour until completely dissolved.

[0062] Step 3: Add 1g of γ-glycidoxypropyltrimethoxysilane to the solution obtained in Step 2, reflux for 5 hours, wash several times with acetone and ethanol, dry at 65°C for 24 hours, and pulverize to obtain the desired flow pattern regulator.

[0063] Example 6

[0064] A method for preparing a flow pattern modifier for water-based drilling fluids includes the following steps:

[0065] Step 1: Add 1g of nano lithium soapstone (LAP) to a certain amount of deionized water and stir in a 250mL beaker for 10 minutes until the solution becomes clear and transparent. Then transfer the solution in the beaker to a three-necked flask.

[0066] Step 2: Heat the solution obtained in Step 1 to 80°C, slowly add 4g of sodium carboxymethyl cellulose (CMC), and stir for 1 hour until completely dissolved.

[0067] Step 3: Add 2g of γ-aminopropyltriethoxysilane to the solution obtained in Step 2, reflux for 3 hours, wash several times with acetone and ethanol, dry at 65℃ for 24 hours, and pulverize to obtain the desired flow pattern regulator.

[0068] Example 7

[0069] A method for preparing a flow pattern modifier for water-based drilling fluids includes the following steps:

[0070] Step 1: Add 1g of nano lithium soapstone (LAP) to a certain amount of deionized water and stir in a 250mL beaker for 10 minutes until the solution becomes clear and transparent. Then transfer the solution in the beaker to a three-necked flask.

[0071] Step 2: Heat the solution obtained in Step 1 to 40°C, slowly add 4g of sodium carboxymethyl cellulose (CMC), and stir for 1 hour until completely dissolved.

[0072] Step 3: Add 2g of γ-aminopropyltriethoxysilane to the solution obtained in step 2, reflux for 15 hours, wash several times with acetone and ethanol, dry at 65℃ for 24 hours, and pulverize to obtain the desired flow pattern regulator.

[0073] To illustrate the effect of the flow pattern regulator of the present invention, a comparative analysis of proportions is provided.

[0074] Comparative Example 1

[0075] Prepare according to the following steps:

[0076] Step 1: Add 1g of nano lithium soapstone (LAP) to a certain amount of deionized water and stir in a 250mL beaker for 10 minutes until the solution becomes clear and transparent. Then transfer the solution in the beaker to a three-necked flask.

[0077] Step 2: Heat the solution obtained in Step 1 to 70°C, slowly add 4g of sodium carboxymethyl cellulose (CMC), and stir for 1 hour until completely dissolved.

[0078] Comparative Example 2

[0079] The flow pattern regulator is a deionized aqueous solution of 4g sodium carboxymethyl cellulose.

[0080] Comparative Example 3

[0081] The flow pattern regulator is a deionized aqueous solution of 1g of nano-lithium saponite.

[0082] The flow pattern regulators obtained from the above embodiments and comparative examples were tested as follows.

[0083] Base slurry preparation and performance evaluation

[0084] 450 mL of tap water, 18.0 g of bentonite (4.0 wt%), and 0.9 g of Na₂CO₃ (0.2 wt%) were stirred at 300 rpm for 10 minutes, followed by stirring at 12000 rpm for 10 minutes. The mixture was then hydrated at room temperature for 24 hours to obtain a 4% bentonite-based slurry for use. Next, 1% flow modifier was added to the 4% bentonite-based slurry, and the mixture was stirred at 10000 rpm for 20 minutes to obtain a homogeneous dispersion for performance testing. For evaluating the salt tolerance of the drilling fluid, the preparation method was the same as for the freshwater-based drilling fluid, only requiring the addition of different mass fractions of NaCl. To evaluate the thermal stability of the drilling fluid and the effect of high temperature on its rheological properties, the drilling fluid was placed in a sealed aging tank and aged for 16 hours in a hot roller furnace (Qingdao Haitongda GW300) set at 150℃.

[0085] Using a six-speed rotational viscometer (ZNN-D6B, Qingdao Tongchun Petroleum Instrument Co., Ltd., China), the values ​​at 600, 300, 200, 100, 6, and 3 rpm were recorded as θ. 600 θ 300 θ 200 θ 100 θ6 and θ3. The drilling fluid was stirred at 10000 r / min for 10 min before measurement. The rheological properties of the drilling fluid were tested at room temperature and atmospheric pressure, and the apparent viscosity (AV), plastic viscosity (PV), and dynamic shear force (YP) rheological parameters were calculated according to the American Petroleum Institute (API) standard.

[0086] The test results are shown in Table 1.

[0087] Table 1. Rheological properties of flow pattern modifiers As shown in Table 1, Examples 1-5 all exhibited good rheological properties before and after aging at 150℃. Examples 1-3 showed better shear strength. Example 4 had a lower viscosity loss rate. Example 5 had poor shear strength and viscosity retention. The results of these examples demonstrate that the flow modifier of the present invention can enhance the internal network structure of the drilling fluid under high-temperature conditions, giving it excellent shear strength and playing a decisive role in suspending drilling cuttings and cleaning the well bottom. Example 3 showed better results. The flow modifiers provided in the comparative examples were less effective. In Comparative Example 1, the physical mixing of sodium carboxymethyl cellulose and nano-lithium saponite did not highlight their special synergistic effect, and the rheological properties became uncontrolled after aging. In Comparative Example 2, sodium carboxymethyl cellulose alone, as a flow modifier, also lost its effect at high temperatures, and the drilling fluid performance was damaged. In Comparative Example 3, nano-lithium saponite alone, as a flow modifier, had a certain shear strength effect and exhibited a thickening effect after aging, demonstrating the characteristics of nano-lithium saponite.

[0088] The salt resistance of the flow pattern modifiers obtained in Example 3 and Comparative Example 2 was evaluated. Rheological properties were tested by adding 0–20% NaCl to the flow pattern modifiers obtained in Example 3 and Comparative Example 2, and the results are shown in Tables 2 and 3.

[0089] Table 2. Salt resistance test results of Example 3

[0090]

[0091] Table 3. Salt resistance test results of Comparative Example 2

[0092]

[0093] As shown in Tables 2 and 3, adding 0%-20% NaCl before aging kept the AV, PV, and YP of the drilling fluid stable. However, the rheological properties of the fluid after adding the flow modifier from Comparative Example 2 decreased: AV from 49 mPa·s to 25 mPa·s, PV from 37 mPa·s to 20 mPa·s, and YP from 12 Pa to 4 Pa. This was mainly due to the decrease in NaCl content. +The increasing concentration compresses the diffusion double layer of clay particles, leading to a decrease in zeta potential, reduced dispersion ability, and deterioration of rheological properties. The rheological properties (AV, PV, YP) ​​of the drilling fluid aged at 150℃ for 16 hours after adding various salt concentrations all decreased to some extent. The rheological properties of the drilling fluid with the flow pattern modifier in Example 3 decreased slowly and remained relatively stable, while the rheological properties of the drilling fluid in Comparative Example 2 changed drastically, which is detrimental to suspending cuttings and cleaning the wellbore. Analysis shows that the introduction of nano-lithium saponite is beneficial to enhancing the salt resistance of the polymer. A protective layer is formed on the CMC chain through hydrogen bonds, electrostatic attraction, and Si-OC bonds connected with the silane coupling agent, enhancing chain rigidity and inhibiting polymer chain curling caused by salt intrusion. Therefore, the modified nanocomposite polymer has better performance as a drilling fluid treatment agent.

[0094] The temperature resistance performance of Example 3 and Comparative Example 2 was evaluated. The flow pattern modifiers in Example 3 and Comparative Example 2 were evaluated for their temperature resistance at temperatures ranging from 150℃ to 180℃, as shown in Table 4.

[0095] Table 4. Temperature resistance of Example 3 and Comparative Example 2

[0096]

[0097] As shown in Table 4, the rheological properties of the water-based drilling fluid with sodium carboxymethyl cellulose (LCC) added in Comparative Example 2 decreased significantly after aging at temperatures above 150°C, with an apparent viscosity reduction rate of 75%. This indicates that as the temperature increases, high temperatures cause oxidative degradation and hydrogen bond breakage of the natural polymer, reducing its adsorption capacity for bentonite and thus weakening the spatial network structure, thereby lowering the viscosity of the drilling fluid. In contrast, the nanocomposite material in Example 3 enhances the thermal stability of the drilling fluid. After aging at 180°C, the apparent viscosity remained at 24 mPa·s, with a viscosity reduction rate of only 35%. This is mainly because the layered disc nanoparticles (LAP) can electrostatically adsorb bentonite particles and provide protection by coating the natural polymer chains through coupling layers. Therefore, at high temperatures, the composite material can still maintain good structural strength, forming a robust spatial network structure in the water-based drilling fluid, enhancing the structural viscosity, and ensuring the drilling fluid's ability to suspend cuttings, barite, and clean the wellbore at high temperatures.

[0098] Figure 1 The schematic diagram shows the reaction mechanism of nano-lithium saponite, sodium carboxymethyl cellulose, and silane coupling agent, which includes the following three steps:

[0099] 1) First, in the presence of water, the silane coupling agent undergoes hydrolysis to produce organosilicon alcohols, and the products are adsorbed onto LAP and CMC through hydrogen bonding.

[0100] 2) Secondly, since silanol groups are difficult to exist stably, organosilicon compounds undergo further self-condensation to form oligomers, while simultaneously undergoing etherification reactions with the hydroxyl groups on the surface of inorganic LAP.

[0101] 3) Finally, due to the electrostatic adsorption of the protonated amino groups on the silane coupling agent and the carboxyl groups on the CMC, and the continued condensation reaction of the silane coupling agent to form a polysiloxane network structure, it can be concluded that the main reason for the enhanced thermal stability of the LAP-CMC nanocomposite polymer is the protective effect of the polysiloxane film structure formed on the CMC surface by the silane coupling agent. Furthermore, the introduction of LAP material, through electrostatic adsorption and synergistic effect with bentonite, forms a robust spatial network structure, enhancing the stability of both the composite polymer and the drilling fluid.

[0102] The flow modifier obtained in this invention enables water-based drilling fluids to maintain stable rheological properties after aging at 150°C. Furthermore, even after aging at 180°C or under conditions of 20% sodium chloride intrusion, the flow modifier still protects the drilling fluid. Its high-temperature resistance mechanism primarily involves the hydrolysis of the silane coupling agent to produce organosilanols, which subsequently undergo condensation polymerization to form polysiloxane structures that adsorb onto the CMC molecular chains and interspersed within the polymer network structure, enhancing the polymer's thermal stability. The introduction of LAP nanomaterials further enhances the drilling fluid's spatial network structure through hydrogen bonding and electrostatic adsorption, maintaining good dispersion properties of bentonite particles, improving the drilling fluid's rheological properties, and enhancing its ability to suspend cuttings and clean the wellbore.

Claims

1. A flow pattern modifier for water-based drilling fluids, characterized in that, Including by weight parts: 30-50 parts of sodium carboxymethyl cellulose, 10-30 parts of nano-lithium saponite, and 10-30 parts of silane coupling agent; the silane coupling agent is one of γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, and γ-glycidoxypropyltrimethoxysilane.

2. The flow pattern modifier for water-based drilling fluid according to claim 1, characterized in that, Including by weight parts: 30-40 parts of sodium carboxymethyl cellulose, 10-20 parts of nano-lithium saponite, and 10-20 parts of silane coupling agent; the silane coupling agent is one of γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, and γ-glycidoxypropyltrimethoxysilane.

3. The flow pattern modifier for water-based drilling fluid according to claim 1, characterized in that, The composition, by weight, includes: 40 parts sodium carboxymethyl cellulose, 10 parts nano lithium saponite, and 20 parts silane coupling agent.

4. The flow pattern modifier for water-based drilling fluid according to claim 1, characterized in that, The composition, by weight, includes: 30 parts sodium carboxymethyl cellulose, 10 parts nano lithium saponite, and 20 parts silane coupling agent.

5. A flow pattern modifier for water-based drilling fluid according to claim 1, characterized in that, The composition, by weight, includes: 30 parts sodium carboxymethyl cellulose, 10 parts nano lithium saponite, and 10 parts silane coupling agent.

6. The method for preparing the flow pattern regulator for water-based drilling fluid as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: Add nano lithium soapstone to the solvent and mix thoroughly; Step 2: Slowly add sodium carboxymethyl cellulose to the solution obtained in Step 1 and mix thoroughly. Step 3: Add silane coupling agent dropwise to the solution obtained in step 2, reflux the reaction, and then wash, dry, and pulverize to obtain the desired flow pattern regulator.

7. The method for preparing a flow pattern regulator for water-based drilling fluid according to claim 6, characterized in that, The reflux reaction time in step 3 is 3 to 15 hours.

8. The method for preparing a flow pattern regulator for water-based drilling fluid according to claim 6, characterized in that, In step 2, the solution obtained in step 1 is first heated to 40-80 °C, and then sodium carboxymethyl cellulose is added.

9. The method of using the flow pattern modifier for water-based drilling fluids obtained by any one of the preparation methods according to claims 6 to 8, characterized in that, Mix the drilling fluid, flow modifier, bentonite, and sodium carbonate thoroughly in the following proportions before use; The drilling fluid, calculated per 450 mL, includes 0.9–6.75 g of flow pattern modifier, 18 g of bentonite, and 0.9 g of sodium carbonate.

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