A hydroxynaphthalene sulfonic acid modified cellulose filtrate reducer for drilling fluid and its preparation and application
By modifying cellulose with hydroxynaphthalenesulfonic acid to form a sulfonate structure, a filtration loss reducer was developed, which solved the problem of insufficient performance of drilling fluid in high temperature and high salinity environments and achieved efficient wellbore and reservoir protection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2024-12-02
- Publication Date
- 2026-06-02
AI Technical Summary
Existing drilling fluid filtration reducers are inadequate in high-temperature and high-salt environments and cannot effectively protect the wellbore and reservoir. Traditional cellulose modifiers have poor stability at high temperatures, and nanocellulose has poor dispersibility.
Cellulose is modified with hydroxynaphthalenesulfonic acid to form a polymer with a sulfonate structure, which improves the thermal stability and salt resistance of the filtrate loss reducer. Cellulose with sulfonate linkages is formed by reacting with hydroxynaphthalenesulfonic acid, which enhances its performance at high temperatures.
It achieves stable filtration loss reduction at 200℃, reduces filtration loss, improves mud cake quality, inhibits clay dispersion, and protects the wellbore and reservoir. It is suitable for deep well and seawater drilling fluid systems.
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Figure CN122127488A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of filtration loss reducers for drilling fluids, specifically relating to a hydroxynaphthalenesulfonic acid modified cellulose drilling fluid filtration loss reducer and its preparation and application. Background Technology
[0002] As a dispersion medium for water-based drilling fluids, water exists in three forms: chemically bound water, adsorbed water, and free water. Under pressure differential, free water in the drilling fluid permeates into the fissures or pores of the wellbore rock, a process known as filtration. The strength of filtration is usually expressed as the filtration rate or water loss. During filtration, as free water from the drilling fluid enters the rock formation, solid particles in the drilling fluid adhere to the wellbore wall, forming a mud cake.
[0003] During drilling, drilling fluid filtrate can infiltrate the formation, causing hydration and swelling of shale and mudstone. In severe cases, this can lead to wellbore instability and various complex situations, and may even damage the reservoir when it encounters it. Drilling fluid filtrate reducers are among the most commonly used treatments in oil and gas field drilling and hold a crucial position in drilling fluid treatments. Adding filtrate reducers is to adjust drilling fluid properties, forming a thin, dense filter cake on the wellbore during drilling to minimize the impact of filtrate loss on the formation and stabilize the wellbore. Common drilling fluid filtrate reducers include cellulose-starch and polymer-based filtrate reducers, which are widely used due to their non-toxic, biodegradable, and environmentally friendly properties. In recent years, with the advancement of petroleum exploration technology, the number of challenging wells, such as deep wells and extended reach wells, has gradually increased. Downhole temperatures and salinity are also rising, placing higher demands on drilling fluid performance, which traditional filtrate reducers can no longer meet.
[0004] CN113322052A discloses a novel polyanionic cellulose filtration loss reducer and its preparation method. The method involves esterifying cellulose with maleic anhydride and neutralizing it with alkali to obtain a maleic ester cellulose salt. Introducing long hydrophobic chains into the cellulose structure further improves its film-forming properties on the wellbore, which is beneficial for improving filter cake quality and reducing water loss. However, this filtration loss reducer only reaches a maximum temperature resistance of 130℃, indicating poor high-temperature stability. CN115926761A discloses a method for preparing a modified cellulose-based filtration loss reducer. Based on existing cellulose-based filtration loss reducers containing only carboxyl and hydroxyl groups, sulfonic acid groups are introduced; however, its temperature resistance only reaches 160℃. CN116836339A discloses an environmentally friendly high-temperature and high-salt filtration loss reducer, its preparation method, and its application. It uses microcrystalline cellulose to prepare nanocellulose crystals, and then grafts the prepared nanocellulose crystals to form a modified nanocellulose filtration loss reducer. Grafting with olefin monomers enhances the temperature resistance of cellulose, ensuring good performance at high temperatures of 200°C. However, the nanocellulose crystals have small particle size (nanoscale), poor dispersibility in aqueous solution, and are prone to agglomeration. Summary of the Invention
[0005] To address the aforementioned problems, this patent provides a filtration loss reducer, which modifies cellulose with hydroxynaphthalenesulfonic acid to obtain a polymer containing a sulfonate structure, thereby improving the thermal stability of the filtration loss reducer.
[0006] The first aspect of this application protects a filtration loss reducer for drilling fluids modified with hydroxynaphthalenesulfonic acid, said filtration loss reducer comprising cellulose modified with hydroxynaphthalenesulfonic acid; said cellulose is a carboxyl-modified cellulose; the monomeric structural formula of said hydroxynaphthalenesulfonic acid is as shown in Formula I:
[0007]
[0008] In Formula I, at least one -OH group is included at each position except for the sulfonic acid group.
[0009] In this invention, hydroxynaphthalene sulfonic acid modified cellulose refers to cellulose formed by the reaction of the sulfonic acid group in hydroxynaphthalene sulfonic acid with the hydroxyl group on cellulose to form cellulose with sulfonate ester linkages, which can improve its high-temperature stability; and the cellulose surface still has a large number of hydroxyl groups, which can adsorb a large amount of water, and the structure is stable, with broad application prospects and is worth promoting.
[0010] Compared to sulfonic acid, hydroxynaphthalene sulfonic acid has the advantage of having a naphthalene ring, resulting in a more stable structure. Using hydroxynaphthalene sulfonic acid to modify carboxyl-modified cellulose, a filtration loss reducer can be prepared, exhibiting excellent thermal stability, withstanding temperatures up to 200℃; it also possesses excellent salt resistance; effectively increasing drilling fluid viscosity, reducing filtration loss, and improving mud cake quality; inhibiting clay dispersion, controlling formation mud production, and ensuring drilling fluid cleanliness; and reducing wellbore enlargement, which is beneficial for protecting oil and gas reservoirs.
[0011] According to some preferred embodiments of this application, the carboxyl-modified cellulose includes carboxymethyl cellulose and carboxyethyl cellulose.
[0012] According to some preferred embodiments of this application, the molecular weight of the filtration reduction agent is 80,000 to 120,000 Da; the molecular weight of the filtration reduction agent may be 80,000 Da, 90,000 Da, 100,000 Da, 110,000 Da, 120,000 Da or a range thereof; in some preferred embodiments, the molecular weight of the filtration reduction agent is 90,000 to 100,000 Da.
[0013] The filtration loss reducer for hydroxynaphthalenesulfonic acid modified cellulose drilling fluid provided by this invention has a molecular weight that is too high, which will lead to poor dispersion, easy aggregation, and increased drilling fluid viscosity, thereby reducing drilling speed; while the filtration loss reducer has a molecular weight that is too low, which will lead to poor thermal stability and weak resistance to salt contamination, and will not play the role of reducing filtration loss and improving thermal stability.
[0014] The second aspect of this application protects a method for preparing the above-mentioned hydroxynaphthalenesulfonic acid modified cellulose drilling fluid filtration reducer, comprising: mixing raw materials including hydroxynaphthalenesulfonic acid, carboxyl-modified cellulose and a complexing agent evenly, reacting and then drying to obtain the product.
[0015] The reaction of hydroxynaphthalenesulfonic acid with cellulose involves a sulfonation process. Under strong base catalysis, the sulfonic acid group in hydroxynaphthalenesulfonic acid can be transferred to the hydroxyl group of carboxyl-modified cellulose, replacing the hydroxyl group to form a sulfonate ester link. This changes the physical and chemical properties of carboxyl-modified cellulose, enhancing its hydrophilicity, ion exchange capacity or other functionalities, giving it better solubility, adsorption properties or potential as a functional material.
[0016] The preparation method of this invention is simple, the raw materials are widely available, the reaction is mild, and it is suitable for industrial application.
[0017] According to some embodiments of this application, the reaction further includes adjusting the pH value to 8-10;
[0018] And / or, the complexing agent includes sodium tripolyphosphate and / or sodium hexametaphosphate.
[0019] Sodium tripolyphosphate and / or sodium hexametaphosphate mainly function to complex with metal ions such as calcium and magnesium ions, reducing the impact of impurities introduced during the reaction, and also improving the calcium and magnesium resistance of the filtration loss reducer; in addition, they can also be used as surfactants to regulate the modification reaction, especially for the reaction of polyhydroxynaphthalenesulfonic acid.
[0020] According to some embodiments of this application, the amount of the complexing agent added is 0.4wt% to 0.6wt% of the amount of hydroxynaphthalenesulfonic acid added.
[0021] According to some embodiments of this application, the mass ratio of hydroxynaphthalenesulfonic acid to carboxyl-modified cellulose is 1:
[0022] (0.5~7), for example, it can be 1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7 or a range thereof.
[0023] According to some embodiments of this application, hydroxynaphthalenesulfonic acid is prepared from hydroxynaphthalenesulfonate.
[0024] According to some preferred embodiments of this application, the method for preparing carboxymethyl cellulose includes: mixing and reacting cellulose, chloroacetic acid, and an alkaline solution to obtain the cellulose.
[0025] According to some preferred embodiments of this application, the fiber is a plant fiber; preferably, the plant fiber is derived from at least one of sugarcane, cotton, fruit peel, and plant pulp.
[0026] After cellulose from different sources is modified with carboxyl groups and combined with hydroxynaphthalenesulfonic acid, the resulting filtration loss reducers have slight differences in apparent viscosity (AV), yield value (YP), plastic viscosity (PV), and static shear force in drilling fluid. However, their filtration loss reduction performance at high temperature (200℃) is better than that of commercial filtration loss reducers.
[0027] According to some preferred embodiments of this application, the mass ratio of the fiber to chloroacetic acid is 0.5 to 2.
[0028] According to some preferred embodiments of this application, the preparation method of the carboxymethyl cellulose is as follows: the fiber reacts with an alkaline solution at room temperature for 0.5 to 2 hours; then chloroacetic acid is added, and the reaction is carried out at 40 to 80°C for 1 to 3 hours.
[0029] In the preparation of carboxymethyl cellulose, if the reaction time after adding vinyl chloride is too short, the reaction will be insufficient or incomplete; if the reaction time is too long, side reactions will occur. After the reaction is complete, the mixture should be cooled with tap water or allowed to cool naturally to room temperature before drying. The drying time should be 24–72 hours.
[0030] The raw material used to prepare carboxymethyl cellulose is waste biomass resources. By modifying cellulose, the advantages of cellulose as a filtration loss reducer are retained while the disadvantages of cellulose are improved, and the waste biomass resources are reused.
[0031] A third aspect of this application protects the use of the above-mentioned hydroxynaphthalenesulfonic acid modified cellulose drilling fluid filtration reducer or the hydroxynaphthalenesulfonic acid modified cellulose drilling fluid filtration reducer prepared by the above preparation method in drilling fluid.
[0032] All of the above-mentioned raw materials used in this invention can be prepared in-house or purchased commercially; this invention does not impose any particular limitations on them.
[0033] Beneficial effects of the present invention
[0034] The filtration loss reducer of this application exhibits excellent thermal stability, withstanding temperatures up to 200℃; strong resistance to salt and calcium / magnesium contamination; effectively increasing drilling fluid viscosity, reducing filtration loss, and improving mud cake quality; inhibiting clay dispersion, controlling formation mud production, and ensuring drilling fluid cleanliness; and reducing wellbore enlargement, which is beneficial for protecting oil and gas reservoirs. It is particularly suitable for seawater drilling fluid systems, as well as deep and ultra-deep well drilling fluid systems.
[0035] The raw material used to prepare carboxymethyl cellulose is waste biomass resources. It retains the advantages of cellulose as a filtration loss reducer while improving its disadvantages, and realizes the reuse of waste biomass resources.
[0036] The raw materials for the filtration loss reducing agent in this application are widely available, the preparation method is simple, the process conditions are mild, and there are no special requirements, making it suitable for industrial production applications. Detailed Implementation
[0037] Example 1
[0038] A method for preparing a filtration loss reducer for hydroxynaphthalenesulfonic acid-modified cellulose drilling fluid includes the following steps:
[0039] (1) Preparation of carboxymethyl cellulose: 100g sugarcane peel, 0.5g sodium hydroxide and 100g water were added to a three-necked flask in sequence. The mixture was stirred at room temperature for 0.5h. Then 200g chloroacetic acid was added and the mixture was stirred at 40℃ for 1h to obtain carboxymethyl cellulose.
[0040] (2) Preparation of filtration loss reducer: 10g of 2-hydroxynaphthalenesulfonic acid, 10g of carboxymethyl cellulose from step (1), and 0.5g of sodium tripolyphosphate were added to a reaction vessel and reacted for 0.5h. Sodium hydroxide was added to adjust the pH of the system to 8-10. Then, the system was cooled to room temperature with cold water or ice water and dried at 105℃ for 24h to obtain hydroxynaphthalenesulfonic acid modified cellulose.
[0041] The molecular weight of the prepared filtration loss reducer is 90,000 Da.
[0042] Example 2
[0043] A method for preparing a filtration loss reducer for hydroxynaphthalenesulfonic acid-modified cellulose drilling fluid includes the following steps:
[0044] (1) Preparation of carboxymethyl cellulose: 100g mango peel, 0.8g sodium hydroxide and 100g water were added to a three-necked flask in sequence and reacted at room temperature for 1h. Then 100g chloroacetic acid was added and the mixture was stirred at 60℃ for 2h to obtain carboxymethyl cellulose.
[0045] (2) Preparation of filtration loss reducer: 10g of 3-hydroxynaphthalenesulfonic acid, 10g of carboxymethyl cellulose from step (1), and 0.5g of sodium hexametaphosphate were added to the reaction vessel and reacted for 1h. Sodium hydroxide was added to adjust the pH of the system to 8-10. Then, the system was cooled to room temperature with cold water or ice water and dried at 105℃ for 48h to obtain hydroxynaphthalenesulfonic acid modified cellulose.
[0046] The molecular weight of the prepared filtration loss reducer is 98,000 Da.
[0047] Example 3
[0048] A method for preparing a filtration loss reducer for hydroxynaphthalenesulfonic acid-modified cellulose drilling fluid includes the following steps:
[0049] (1) Preparation of carboxymethyl cellulose: 100g watermelon rind, 0.8g sodium hydroxide and 100g water were added to a three-necked flask in sequence and reacted at room temperature for 1h. Then 50g chloroacetic acid was added and the mixture was stirred at 80℃ for 3h to obtain carboxymethyl cellulose.
[0050] (2) Preparation of filtration loss reducer: First, sodium 2-hydroxynaphthalenesulfonate was reacted with concentrated hydrochloric acid in a 1:1 ratio to obtain hydroxynaphthalenesulfonic acid. Then, 10g of 2-hydroxynaphthalenesulfonic acid, 10g of carboxymethyl cellulose from step (1), and 0.5g of sodium hexametaphosphate were added to the reaction vessel and reacted for 1.5h. Sodium hydroxide was added to adjust the pH of the system to 8-10. Afterward, the system was cooled to room temperature with cold water or ice water and dried at 105℃ for 48h to obtain hydroxynaphthalenesulfonic acid modified cellulose.
[0051] The molecular weight of the prepared filtration loss reducer is 100,000 Da.
[0052] Comparative Example 1
[0053] Commercial filtration reducers
[0054] Low-viscosity CMC (sodium carboxymethyl cellulose), purchased from Shandong Deshunyuan Petroleum Technology Co., Ltd., is used as a filtration loss reducer.
[0055] Comparative Example 2
[0056] Commercial filtration reducers
[0057] Low-viscosity CMC (sodium carboxymethyl cellulose), purchased from Zhong Sheng Petroleum Technology Co., Ltd., is used as a filtration loss reducer.
[0058] Comparative Example 3
[0059] Modified grapefruit peel as a filtration loss reducer
[0060] 12g of grapefruit peel powder was added to a beaker containing 150g of deionized water and stirred until homogeneous. Then, 20g of sodium hydroxide was added, and the mixture was alkalized and gelatinized at 64℃ for 0.5h. 48g of chloroacetic acid was added, and the mixture was stirred at 77℃ for 1h to obtain carboxymethyl grapefruit peel. Next, 24.8g of a cationic etherifying agent was added, and the mixture was stirred at 90℃ for 3h to obtain cationic carboxymethyl grapefruit peel. The reaction temperature was adjusted to 60℃, and then 6.2g of sodium hydroxide, 25.6g of 2-acrylamido-2-methylpropanesulfonic acid, 54.8g of acrylamide, and 40mL of deionized water were added sequentially, and the mixture was stirred for 0.5h. After finely adjusting the pH of the reaction solution to 8-9, 1.2g of ammonium persulfate was added, and the mixture was stirred at 60℃ for 1h to obtain a brown viscous liquid. This liquid was placed in an oven and dried at 80℃. After drying, it was ground into powder to obtain modified grapefruit peel (MGE). This powder was used as a filtration loss reducer.
[0061] Implementation Results Example
[0062] The filtration loss reducers prepared according to Examples 1-3 and Comparative Examples 1-3 were added to different drilling fluid systems, and their filtration loss was measured to evaluate the performance of the filtration loss reducers. The results are shown in Table 1, where the base fluid + Example 1 is sample 1; the base fluid + Example 2 is sample 2; the base fluid + Example 3 is sample 3; the base fluid + Comparative Example 1 is sample 4; the base fluid + Comparative Example 2 is sample 5; and the base fluid + Comparative Example 3 is sample 6.
[0063] Drilling fluids were prepared according to the standard GB-T16783.1 Field Testing of Drilling Fluids for Petroleum and Natural Gas Industry - Part 1: Water-based Drilling Fluids, and their rheological properties (including apparent viscosity AV, plastic viscosity PV, and yield value YP) and filtration loss (API filtration loss FL) were measured. AP1 HTHP filtration loss FL HTHP ), Inhibitory (expressed as 4h shale swelling amount).
[0064] (1) Soil base slurry: Add 20.0g (weighed to the nearest 0.01g, the same below) of bentonite for drilling fluid test slurry preparation (dried in a constant temperature drying oven at 105℃±3℃ for 4h) and 1.0g of anhydrous sodium carbonate to 400mL of distilled water, stir at high speed for 20min, stopping at least twice during this period to scrape off the adhering material on the container wall, and let it stand in a sealed container at room temperature for 24h. The amount of filtration loss reducer added is calculated as 1%, which is 4g.
[0065] Table 1. Test Results Data for Examples and Comparative Examples
[0066]
[0067] The filtration loss reducers prepared in Examples 1-3 all effectively reduced the filtration loss of drilling fluid at both room temperature and 200°C. However, commercial filtration loss reducers such as CMC or modified grapefruit peel, when used as filtration loss reducers, could not withstand the harsh environments of high and ultra-high temperatures. Hydroxynaphthalene sulfonic acid-modified cellulose exhibited better performance than commercial filtration loss reducers or modified grapefruit peel. Combined with the 4-hour shale swelling data, it can be seen that the filtration loss reducer of this application can inhibit clay dispersion, control formation mud formation, and ensure drilling fluid cleanliness.
[0068] (2) Clay-free reservoir protection drilling fluid system
[0069] Base slurry (400mL): 5-10% sodium formate + 1-5% potassium chloride + 0.1-0.5% NaOH + 1% Na2SO3. The amount of filtration loss reducer added is calculated at 1%, which is 4g.
[0070] Table 2 Test Results Data for Examples and Comparative Examples
[0071]
[0072] As can be seen from Table 2, the filtration loss reducers prepared in Examples 1-3 can all reduce the filtration loss of drilling fluid at room temperature and at a high temperature of 200°C. However, the commercial filtration loss reducers CMC or modified grapefruit peel, as filtration loss reducers, cannot resist high temperatures and are close to complete loss at 200°C. The cellulose modified with hydroxynaphthalenesulfonic acid has a better effect than conventional filtration loss reducers, and Example 3 has the best effect.
[0073] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on 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 terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.
Claims
1. A filtration loss reducer for hydroxynaphthalenesulfonic acid-modified cellulose drilling fluid, characterized in that, The filtration loss reducing agent comprises cellulose modified with hydroxynaphthalenesulfonic acid; the cellulose is a carboxyl-modified cellulose; the structural formula of the hydroxynaphthalenesulfonic acid is as shown in Formula I: In Formula I, at least one -OH group is included at each position except for the sulfonic acid group.
2. The filtration loss reducer for cellulose drilling fluid modified with hydroxynaphthalenesulfonic acid according to claim 1, characterized in that, The carboxyl-modified celluloses include carboxymethyl cellulose and carboxyethyl cellulose.
3. The filtration loss reducer for cellulose drilling fluid modified with hydroxynaphthalenesulfonic acid according to claim 1 or 2, characterized in that, The molecular weight of the filtration loss reducing agent is 80,000 to 120,000 Da; preferably, the molecular weight of the filtration loss reducing agent is 90,000 to 100,000 Da.
4. A method for preparing a filtration loss reducer for cellulose drilling fluid as described in any one of claims 1-3, characterized in that, include: The raw materials, including hydroxynaphthalenesulfonic acid, carboxyl-modified cellulose, and a complexing agent, are mixed, reacted, and then dried to obtain the final product.
5. The preparation method according to claim 4, characterized in that, The reaction was carried out at a pH of 8-10; And / or, the complexing agent comprises sodium tripolyphosphate and / or sodium hexametaphosphate; preferably, the amount of the complexing agent added is 0.4 wt% to 0.6 wt% of hydroxynaphthalenesulfonic acid.
6. The preparation method according to claim 4 or 5, characterized in that, The mass ratio of hydroxynaphthalenesulfonic acid to carboxyl-modified cellulose is 1:(0.5-7).
7. The preparation method according to any one of claims 4-6, characterized in that, The carboxyl-modified cellulose includes at least one of carboxymethyl cellulose and carboxyethyl cellulose; preferably, the carboxyl-modified cellulose is carboxymethyl cellulose.
8. The preparation method according to claim 7, characterized in that, The method for preparing the carboxymethyl cellulose includes: mixing and reacting raw materials including fiber, chloroacetic acid, and alkaline solution; preferably, the fiber is plant fiber; preferably, the plant fiber is derived from at least one of sugarcane, cotton, fruit peel, and plant pulp; And / or, the mass ratio of the fiber to chloroacetic acid is 0.5 to 2.
9. The preparation method according to claim 8, characterized in that, The specific process is as follows: the fiber reacts with the alkaline solution at room temperature for 0.5 to 2 hours; then chloroacetic acid is added, and the reaction is carried out at 40 to 80°C for 1 to 3 hours.
10. The application of the hydroxynaphthalenesulfonic acid modified cellulose drilling fluid filtration reducer according to any one of claims 1-3 or the hydroxynaphthalenesulfonic acid modified cellulose drilling fluid filtration reducer prepared by any one of claims 4-9 in drilling fluid.