High-temperature-resistant anti-sloughing plugging filtrate reducer and preparation method thereof

Abstract

The invention provides a high-temperature-resistant anti-sloughing plugging filtrate reducer and a preparation method thereof, and belongs to the technical field of anti-sloughing plugging filtrate reducers. The sulfonated asphalt used in the invention is obtained by sulfonating asphalt with specific composition with sulfur trioxide, has better water solubility, not only can effectively block cracks, but also has good effect of inhibiting hydration of shale and excellent high-temperature stability and filtrate loss reduction effect; by adopting the sulfonated phenolic resin grafted with humic acid, the temperature resistance and the salt resistance can be improved, and the hydration expansion of the shale can be inhibited; the ternary polymer is grafted in the sulfonated phenolic resin, so that the temperature resistance, salt resistance and filtrate loss reduction effects are further improved; the sulfonated asphalt and the modified sulfonated phenolic resin are compounded, so that oleophylic components and negatively charged asphalt macromolecules are contained, and the sulfonated asphalt and the modified sulfonated phenolic resin generate a synergistic effect, so that the product has a higher filtrate loss reduction effect and a better borehole wall stabilizing effect.

Description

Technical Field

[0001] This invention belongs to the technical field of anti-collapse, sealing, and filtration loss reduction agents, specifically relating to a high-temperature resistant anti-collapse, sealing, and filtration loss reduction agent and its preparation method. Background Technology

[0002] During oil drilling, when encountering clay layers, the well wall is prone to absorbing water and expanding, which can lead to wellbore narrowing, well wall collapse, increased friction, and in severe cases, even stuck drill bit, seriously affecting the drilling process. Especially in long horizontal wells and extended reach wells, the drilling period is longer, the drilling fluid circulates downhole for a longer time, and the well wall is even more difficult to stabilize for a long period of time.

[0003] Current technologies commonly use anti-collapse sealing fluids and filtration reduction agents to stabilize the wellbore and reduce filtration loss. However, anti-collapse sealing fluids only act as plugs, with poor filtration reduction effects; filtration reduction agents have good filtration reduction effects but lack the effects of plugging, preventing collapse, and inhibiting water absorption and swelling. When these two are used in combination, the ratio must be strictly controlled according to the actual wellbore conditions. Improper ratios may cause negative effects such as foaming and thickening, or even fail to prevent collapse and reduce filtration loss, thus failing to solve the problem of wellbore instability. Oil drilling engineering urgently needs a treatment agent that simultaneously possesses plugging, anti-collapse, and filtration reduction properties. Summary of the Invention

[0004] The purpose of this invention is to provide a high-temperature resistant, anti-collapse, plugging, and filtration loss reducing agent and its preparation method. The high-temperature resistant, anti-collapse, plugging, and filtration loss reducing agent provided by this invention simultaneously exhibits good plugging, anti-collapse, water absorption and swelling inhibition, and filtration loss reduction effects.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a high-temperature resistant, anti-collapse, and filtration-reducing agent, comprising sulfonated asphalt and modified sulfonated phenolic resin, wherein the mass ratio of the sulfonated asphalt to the modified sulfonated phenolic resin is (40~50):(50~60). The sulfonated asphalt is obtained by sulfonating asphalt, and the sulfonating agent is sulfur trioxide; by mass percentage, the asphalt includes 25-35% asphaltenes, 20-40% resins and 20-45% aromatic phenols. The modified sulfonated phenolic resin is a humic acid-polymer grafted sulfonated phenolic resin; the grafted polymer in the modified sulfonated phenolic resin is a ternary polymer of 2-acrylamide-2-methylpropanesulfonic acid, acrylamide and N,N-dimethylacrylamide.

[0006] Preferably, the sulfonation includes: mixing asphalt, organic solvent and sulfur trioxide, and then carrying out a sulfonation reaction; the sulfonation reaction temperature is 40~50℃, and the reaction time is 1.5~2h; The pH of the system after the sulfonation reaction is adjusted to 7-9, and then the organic solvent is separated to obtain sulfonated asphalt.

[0007] Preferably, the mass ratio of the asphalt, organic solvent and sulfur trioxide is (250~350):(400~600):(400~600) by mass parts.

[0008] Preferably, the mass fraction of grafted humic acid in the modified sulfonated phenolic resin is 5-10%.

[0009] Preferably, the mass fraction of the grafted polymer in the modified sulfonated phenolic resin is 50-60%.

[0010] Preferably, the mass ratio of 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, and N,N-dimethylacrylamide is (190~210):(80~100):(80~120).

[0011] Preferably, the preparation of the modified sulfonated phenolic resin includes the following steps: Phenol, water, humate, sulfite, bisulfite and formaldehyde aqueous solution are first mixed and then subjected to a synthesis reaction to obtain humic acid grafted sulfonated phenolic resin; the synthesis reaction temperature is 110~130℃ and the synthesis reaction time is 4~6h. A second sulfonated phenolic resin grafted with humic acid is mixed with an aqueous solution of sodium hydroxide, 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, N,N-dimethylacrylamide, an initiator, and the humic acid grafted sulfonated phenolic resin and then subjected to a grafting reaction to obtain a modified sulfonated phenolic resin; the grafting reaction temperature is 50~60℃ and the grafting reaction time is 3~5h.

[0012] Preferably, the humate is one or both of sodium humate and sodium fulvate.

[0013] Preferably, the mass ratio of phenol, sulfite and bisulfite is (80~120):(60~70):(55~65).

[0014] The present invention also provides a method for preparing the high-temperature resistant, anti-collapse, plugging and filtration loss reducing agent described in the above technical solution, comprising: mixing the modified sulfonated phenolic resin with sulfonated asphalt to obtain the high-temperature resistant, anti-collapse, plugging and filtration loss reducing agent.

[0015] This invention provides a high-temperature resistant, anti-collapse, plugging, and filtration loss reducing agent, comprising sulfonated asphalt and modified sulfonated phenolic resin, wherein the mass ratio of the sulfonated asphalt to the modified sulfonated phenolic resin is (40~50):(50~60); the sulfonated asphalt is obtained by sulfonation of asphalt, and the sulfonating agent is sulfur trioxide; by mass percentage, the asphalt comprises 25~35% asphaltenes, 20~40% gums, and 20~45% aromatic phenols; the modified sulfonated phenolic resin is a humic acid-polymer grafted sulfonated phenolic resin; the polymer in the modified sulfonated phenolic resin is a ternary polymer of 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, and N,N-dimethylacrylamide. The sulfonated asphalt used in this invention is obtained by sulfonating a specific composition of asphalt with sulfur trioxide, resulting in better water solubility. It not only effectively seals cracks but also effectively inhibits shale hydration swelling and exhibits excellent high-temperature stability and reduced filtration loss. The sulfonated phenolic resin grafted with humic acid improves temperature and salt resistance and inhibits shale hydration swelling. Grafting ternary polymers into the sulfonated phenolic resin further enhances its temperature resistance, salt resistance, and filtration loss reduction effects. The combination of sulfonated asphalt and modified sulfonated phenolic resin provides both oleophilic components and negatively charged asphalt macromolecules, which, while sealing wellbore pores, adsorb onto the positively charged clay surface, preventing shale particle dispersion and reducing water infiltration into shale pores, thus preventing collapse and stabilizing the wellbore. The synergistic effect of sulfonated asphalt and modified sulfonated phenolic resin results in a product with even higher filtration loss reduction and wellbore stabilization effects. The results of the embodiments show that the high-temperature and high-pressure filtration loss of the anti-high-temperature and anti-collapse sealing and filtration loss reducing agent provided by the present invention is less than 20 mL, the shale recovery rate is higher than 94%, and the relative expansion rate is less than 40%. Detailed Implementation

[0016] All raw materials used in this invention are not particularly limited in their source; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0017] There are no particular restrictions on the purity of any of the raw materials used in this invention, but industrially pure raw materials are preferred.

[0018] This invention provides a high-temperature resistant, anti-collapse, and filtration-reducing agent, comprising sulfonated asphalt and modified sulfonated phenolic resin, wherein the mass ratio of the sulfonated asphalt to the modified sulfonated phenolic resin is (40~50):(50~60). The sulfonated asphalt is obtained by sulfonating asphalt, and the sulfonating agent is sulfur trioxide; by mass percentage, the asphalt includes 25-35% asphaltenes, 20-40% resins and 20-45% aromatic phenols. The modified sulfonated phenolic resin is a humic acid-polymer grafted sulfonated phenolic resin; the grafted polymer in the modified sulfonated phenolic resin is a ternary polymer of 2-acrylamide-2-methylpropanesulfonic acid, acrylamide and N,N-dimethylacrylamide.

[0019] In this invention, the sulfonated asphalt is obtained by sulfonating asphalt, and the sulfonating agent is sulfur trioxide.

[0020] In this invention, the sulfonation preferably includes: mixing asphalt, an organic solvent, and sulfur trioxide, then carrying out a sulfonation reaction; after the reaction is complete, adding alkaline water to adjust the pH of the reaction system to 7-9, separating the organic solvent, and obtaining sulfonated asphalt; the sulfonation reaction temperature is preferably 40-50℃, more preferably 45℃; the reaction time is preferably 1.5-2 hours. Using the above sulfonation method is beneficial to the sulfonation reaction and further improves the sealing effect of the product.

[0021] In this invention, the asphalt comprises 25-35% asphaltenes, 20-40% resins, and 20-45% aromatic phenols by mass percentage; preferably 27-32% asphaltenes, 25-35% resins, and 32-42% aromatic phenols. By using asphalt with a specific composition, this invention ensures excellent filtration loss reduction, lowers relative expansion rate, and improves wellbore stability.

[0022] In one embodiment of the present invention, the asphalt may be petroleum asphalt; the petroleum asphalt may also include saturated components in addition to the above-mentioned components.

[0023] As one embodiment of the present invention, the asphalt can be crushed into 20-mesh small particles before use.

[0024] In one embodiment of the present invention, the organic solvent may be a light oil, specifically kerosene.

[0025] In this invention, the preferred mass ratio of asphalt, organic solvent, and sulfur trioxide, by weight, is (250-350):(400-600):(400-600), more preferably (270-320):(450-550):(450-550). As one embodiment of this invention, the mass ratio of asphalt, organic solvent, and sulfur trioxide can be 300:600:500, 250:400:400, or 350:550:450. A mass ratio of asphalt, organic solvent, and sulfur trioxide within the above ranges is beneficial for asphalt sulfonation.

[0026] As one embodiment of the present invention, the mixing of asphalt, organic solvent and sulfur trioxide can be carried out by: adding asphalt to light oil, stirring and heating to 35°C to fully disperse the asphalt, then heating to 45°C and adding sulfur trioxide.

[0027] In one embodiment of the present invention, an alkaline solution can be used to adjust the pH value of the system after the reaction; the alkaline solution is preferably an aqueous solution of sodium hydroxide, and the mass fraction of sodium hydroxide in the aqueous solution is preferably 35-40%. The alkaline solution can neutralize the sulfur trioxide remaining in the sulfonation reaction and convert the sulfonic acid groups in the sulfonated asphalt into negatively charged sulfonate groups, thereby improving the water solubility of the sulfonated asphalt; the above-mentioned concentration of sodium hydroxide aqueous solution is conducive to the neutralization reaction.

[0028] In one embodiment of the present invention, the organic solvent can be separated by static stratification; after separating the organic solvent, the remaining phase can be dried at a temperature of 105°C; after drying, the product can be pulverized to obtain sulfonated asphalt; the particle size of the sulfonated asphalt is 100 mesh.

[0029] In this invention, the modified sulfonated phenolic resin is a humic acid-polymer grafted sulfonated phenolic resin. In this invention, the mass fraction of grafted humic acid in the modified sulfonated phenolic resin is preferably 5-10%, more preferably 7-9%. A mass fraction of grafted humic acid within the above range is beneficial for further improving the product's temperature resistance and salt resistance.

[0030] In this invention, the graft polymer in the modified sulfonated phenolic resin is a ternary polymer of 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, and N,N-dimethylacrylamide. In this invention, the mass fraction of the graft polymer in the modified sulfonated phenolic resin is preferably 50-60%, more preferably 53-55%; as one embodiment of this invention, the mass fraction of the graft polymer in the modified sulfonated phenolic resin can be 52%, 53.6%, 54.2%, 54.5%, 55%, or 58%. A mass fraction of the graft polymer in the modified sulfonated phenolic resin within the above range is beneficial for improving the filtration loss reduction effect.

[0031] In this invention, the preferred mass ratio of 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, and N,N-dimethylacrylamide in the grafted polymer is (190~210):(80~100):(80~120), more preferably (195~205):(85~95):(90~110). As one embodiment of this invention, the mass ratio of 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, and N,N-dimethylacrylamide can be 210:90:100, 190:100:80, or 190:80:120. A mass ratio of 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, and N,N-dimethylacrylamide within the above ranges is beneficial for further improving the filtration loss reduction effect.

[0032] In this invention, the preparation of the modified sulfonated phenolic resin preferably includes the following steps: Phenol, water, humate, sulfite, bisulfite, and formaldehyde aqueous solution are first mixed and then subjected to a synthesis reaction to obtain humic acid-grafted sulfonated phenolic resin; the synthesis reaction temperature is 110~130℃ and the synthesis reaction time is 4~6h. A second sulfonated phenolic resin grafted with humic acid is mixed with an aqueous solution of sodium hydroxide, 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, N,N-dimethylacrylamide, an initiator, and the humic acid grafted sulfonated phenolic resin and then subjected to a grafting reaction to obtain a modified sulfonated phenolic resin; the grafting reaction temperature is 50~60℃ and the grafting reaction time is 3~5h.

[0033] In this invention, phenol, water, humate, sulfite, bisulfite, and formaldehyde aqueous solution are first mixed and then subjected to a synthesis reaction to obtain humic acid-grafted sulfonated phenolic resin.

[0034] In one embodiment of the present invention, the phenol can be 80-120 parts or 90-110 parts by weight, specifically 84 parts, 85 parts, 90 parts, 100 parts, or 110 parts. Using the above-mentioned parts by weight of phenol with other raw materials to prepare sulfonated phenolic resin improves the filtration loss reduction effect.

[0035] The water content can be 310-330 parts or 320 parts based on 80-120 parts by weight of phenol; the present invention uses water as a solvent to dissolve phenol and other raw materials.

[0036] The humate salt can be 90-110 parts or 100 parts based on 80-120 parts by weight of phenol. The humate salt can copolymerize with phenolic resin to improve the temperature and salt resistance of the phenolic resin.

[0037] In this invention, the humate is preferably one or both of sodium humate and sodium fulvate; in the embodiments of this invention, the humate is sodium humate. The above-mentioned humate is beneficial for copolymerization with phenolic resins.

[0038] In one embodiment of the present invention, the humate salt contains humate ions at a mass content of not less than 60%.

[0039] The sulfite can be 60-70 parts or 66 parts, based on 80-120 parts by weight of phenol. This invention uses sulfite as a sulfonating agent; the sulfite weight percentage within the above range is beneficial for the sulfonation of phenolic resins.

[0040] Based on 80-120 parts by weight of phenol, the bisulfite can be 55-65 parts or 60 parts. This invention uses bisulfite and sulfite as sulfonating agents; the weight percentage of bisulfite within the above range is beneficial for the sulfonation of phenolic resins.

[0041] In one embodiment of the present invention, the formaldehyde aqueous solution may contain 37% formaldehyde by mass; based on 80-120 parts by weight of phenol, the formaldehyde aqueous solution may contain 190-220 parts, or 200-210 parts, specifically 195 parts, 200 parts, 205 parts, 208 parts, or 210 parts. When the weight of the formaldehyde aqueous solution is within the above range, it can undergo a polymerization reaction with phenol to generate phenolic resin.

[0042] In one embodiment of the present invention, the first mixing may involve mixing other raw materials first, heating the mixture, and then adding formaldehyde dropwise; the final temperature of the heating is preferably 80-90°C, more preferably 85°C. Adding formaldehyde dropwise helps control the reaction progress and further improves the filtration loss reduction effect.

[0043] In this invention, the temperature of the synthesis reaction is 110~130℃, preferably 120℃; the time of the synthesis reaction is 4~6h, preferably 5h. The parameters of the synthesis reaction being within the above ranges are beneficial to the progress of the reaction.

[0044] After obtaining the humic acid-grafted sulfonated phenolic resin, the present invention preferably involves mixing sodium hydroxide aqueous solution, 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, N,N-dimethylacrylamide, an initiator, and the humic acid-grafted sulfonated phenolic resin in a second mixture and then carrying out a grafting reaction to obtain the modified sulfonated phenolic resin.

[0045] In one embodiment of the present invention, the sodium hydroxide aqueous solution contains 8-10% sodium hydroxide by mass, preferably 9%; based on 150-200 parts of phenolic resin, the mass of the sodium hydroxide aqueous solution can be 600-660 parts. The sodium hydroxide aqueous solution provides an alkaline environment and acts as a catalyst and directing agent for the grafting reaction.

[0046] In one embodiment of the present invention, based on 150-200 parts of phenolic resin, the initiator can be 1.5-2 parts, or 1.8 parts. The initiator is preferably a persulfate; in the embodiments of the present invention, the initiator is ammonium persulfate. The present invention uses an initiator to initiate the grafting reaction; persulfate is a free radical initiator, which is beneficial to the grafting reaction.

[0047] In one embodiment of the present invention, the second mixing may involve mixing other raw materials and stirring them evenly before finally adding an initiator.

[0048] In this invention, the temperature of the grafting reaction is 50-60°C, preferably 55°C; the time of the grafting reaction is 3-5 hours, preferably 4 hours. Parameters within the above ranges are beneficial for the grafting reaction to proceed.

[0049] In one embodiment of the present invention, after the grafting reaction is completed, the obtained product can be dried; the drying temperature can be 105°C; after drying, the product can be pulverized to obtain modified sulfonated phenolic resin; the particle size of the modified sulfonated phenolic resin is 100 mesh.

[0050] In this invention, the mass ratio of sulfonated asphalt to modified sulfonated phenolic resin is (40~50):(50~60); as one embodiment of this invention, the mass ratio of sulfonated asphalt to modified sulfonated phenolic resin can be 45:55 or 50:50. When the mass ratio of sulfonated asphalt to modified sulfonated phenolic resin is within the above range, a synergistic effect can be achieved, resulting in a product with higher filtration loss reduction and wellbore stabilization effects.

[0051] This invention uses asphalt with a specific composition, which is then sulfonated with sulfur trioxide to obtain sulfonated asphalt with better water solubility. This not only effectively seals cracks but also effectively inhibits shale hydration and exhibits excellent high-temperature stability and filtration loss reduction. By introducing humate and sulfonating phenolic resin, the temperature and salt resistance can be improved, and shale hydration swelling can be inhibited. By grafting ternary polymers into sulfonated phenolic resin, the temperature resistance, salt resistance, and filtration loss reduction effects are further improved. The combination of sulfonated asphalt and modified sulfonated phenolic resin contains both oleophilic components and negatively charged asphalt macromolecules, which adsorb onto the positively charged clay surface while sealing wellbore pores, preventing shale particle dispersion and reducing water infiltration into shale pores, thereby playing a role in preventing collapse and stabilizing the wellbore. The synergistic effect of sulfonated asphalt and modified sulfonated phenolic resin results in a product with higher filtration loss reduction and wellbore stabilization effects.

[0052] The present invention also provides a method for preparing the high-temperature resistant, anti-collapse, plugging and filtration loss reducing agent described in the above technical solution, comprising: mixing the modified sulfonated phenolic resin with sulfonated asphalt to obtain the high-temperature resistant, anti-collapse, plugging and filtration loss reducing agent.

[0053] In one embodiment of the present invention, the apparatus for mixing the modified sulfonated phenolic resin and sulfonated asphalt can be a mixing tank, and the mixing time can be 1 hour.

[0054] The preparation method provided by this invention is simple, easy to control, and conducive to obtaining products with stable quality.

[0055] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0056] Example 1 A high-temperature resistant, anti-collapse, plugging, and filtration loss reducing agent is composed of sulfonated asphalt and modified sulfonated phenolic resin in a mass ratio of 45:55. The sulfonated asphalt is obtained by sulfonation of asphalt, and the modified sulfonated phenolic resin is a humic acid-polymer grafted sulfonated phenolic resin. The modified sulfonated phenolic resin contains 7.9% grafted humic acid and 53.6% grafted polymer, which is a ternary polymer obtained by polymerizing 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, and N,N-dimethylacrylamide in a mass ratio of 210:90:100.

[0057] The preparation steps are as follows: 300 parts by weight of asphalt (30% asphaltenes, 25% resins, 42% aromatic phenols, and the balance saturated fraction) were crushed into 20-mesh particles and added to a reactor containing 600 parts by weight of kerosene. The mixture was stirred and heated to 35°C to ensure thorough dispersion of the asphalt. The temperature was then raised to 45°C, and 500 parts by weight of sulfur trioxide were added to the reactor. After the addition was complete, the temperature was maintained for 1.5 hours. 100 parts by weight of sodium hydroxide (40% aqueous solution) was added to adjust the pH of the system to 8. The oil layer was allowed to stand and separated, and then recycled. The water layer was dried at 105°C and crushed to 100 mesh to obtain component A. 2) Add 94 parts by weight of phenol, 320 parts by weight of water, 100 parts by weight of sodium humate, 66 parts by weight of sodium sulfite, and 60 parts by weight of sodium bisulfite to a reactor, heat to 85°C, and then add 208 parts by weight of formaldehyde dropwise. After the addition is complete, heat to 120°C and carry out the synthesis reaction for 5 hours to obtain sulfonated phenolic resin. In another reactor, add 600 parts by weight of water and 60 parts by weight of sodium hydroxide. After the sodium hydroxide dissolves and cools, add 210 parts by weight of AMPS, then add 90 parts by weight of acrylamide and 100 parts by weight of N,N-dimethylacrylamide. After stirring and dissolving, add the sulfonated phenolic resin to the reactor, add 1.8 parts by weight of ammonium persulfate, heat to 55°C and react for 4 hours, dry at 105°C, and pulverize to 100 mesh to obtain component B. 3) Add 45% of component A and 55% of component B into a mixing tank and mix for 1 hour to obtain a high-temperature resistant, anti-collapse, and filtration-reducing agent.

[0058] Example 2 A high-temperature resistant, anti-collapse, plugging, and filtration loss reducing agent is composed of sulfonated asphalt and modified sulfonated phenolic resin in a mass ratio of 50:50. The sulfonated asphalt is obtained by sulfonation of asphalt, and the modified sulfonated phenolic resin is a humic acid-polymer grafted sulfonated phenolic resin. The modified sulfonated phenolic resin contains 9.7% grafted humic acid and 54.2% grafted polymer, which is a ternary polymer obtained by polymerizing 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, and N,N-dimethylacrylamide in a mass ratio of 190:100:80.

[0059] The preparation steps are as follows: 250 parts by weight of asphalt (35% asphaltenes, 30% resins, 32% aromatic phenols, and the balance saturated fraction) were crushed into 20-mesh particles and added to a reactor containing 400 parts by weight of kerosene. The mixture was stirred and heated to 35°C to ensure thorough dispersion of the asphalt. The temperature was then raised to 45°C, and 400 parts by weight of sulfur trioxide were added to the reactor. After the addition was complete, the reaction temperature was maintained for 1.5 hours. 100 parts by weight of sodium hydroxide (40% aqueous solution) was added to adjust the pH of the system to 8.5. The oil layer was allowed to stand and separated, and then recycled. The water layer was dried at 105°C and crushed to 100 mesh to obtain component A. 2) Add 80 parts by weight of phenol, 320 parts by weight of water, 110 parts by weight of sodium humate, 70 parts by weight of sodium sulfite, and 55 parts by weight of sodium bisulfite to a reactor, heat to 85°C, and then add 220 parts by weight of formaldehyde dropwise. After the addition is complete, heat to 120°C and carry out the synthesis reaction for 5 hours to obtain sulfonated phenolic resin. In another reactor, add 600 parts by weight of water and 60 parts by weight of sodium hydroxide. After the sodium hydroxide dissolves and cools, add 190 parts by weight of AMPS, then add 100 parts by weight of acrylamide and 80 parts by weight of N,N-dimethylacrylamide. After stirring and dissolving, add the sulfonated phenolic resin to the reactor, add 2 parts by weight of ammonium persulfate, heat to 55°C and react for 4 hours, dry at 105°C, and pulverize to 100 mesh to obtain component B. 3) Add 50% of component A and 50% of component B into a mixing tank and mix for 1 hour to obtain a high-temperature resistant, anti-collapse, and filtration-reducing agent.

[0060] Example 3 A high-temperature resistant, anti-collapse, plugging, and filtration loss reducing agent is composed of sulfonated asphalt and modified sulfonated phenolic resin in a mass ratio of 50:50. The sulfonated asphalt is obtained by sulfonation of asphalt, and the modified sulfonated phenolic resin is a humic acid-polymer grafted sulfonated phenolic resin. The modified sulfonated phenolic resin contains 7.5% humic acid and 54.5% grafted polymer, which is a ternary polymer obtained by polymerizing 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, and N,N-dimethylacrylamide in a mass ratio of 190:80:120.

[0061] The preparation method is as follows: 350 parts by weight of asphalt (25% asphaltenes, 35% resins, 37% aromatic phenols, and the balance saturated fraction) were crushed into 20-mesh particles and added to a reactor containing 550 parts by weight of kerosene. The mixture was stirred and heated to 35°C to ensure thorough dispersion of the asphalt. The temperature was then raised to 45°C, and 450 parts by weight of sulfur trioxide were added to the reactor. After the addition was complete, the reaction temperature was maintained for 1.5 hours. 100 parts by weight of sodium hydroxide (40% aqueous solution) was added to adjust the pH of the system to 8.2. The oil layer was allowed to stand and separated, and then recycled. The water layer was dried at 105°C and crushed to 100 mesh to obtain component A. 2) 110 parts by weight of phenol, 320 parts by weight of water, 90 parts by weight of sodium humate, 60 parts by weight of sodium sulfite, and 65 parts by weight of sodium bisulfite were added to a reactor. The temperature was raised to 85°C, and then 200 parts by weight of formaldehyde were added dropwise. After the addition was complete, the temperature was raised to 120°C and the synthesis reaction was carried out for 5 hours to obtain sulfonated phenolic resin. In another reactor, 600 parts by weight of water and 60 parts by weight of sodium hydroxide were added. After the sodium hydroxide dissolved and cooled, 190 parts by weight of AMPS were added, followed by 80 parts by weight of acrylamide and 120 parts by weight of N,N-dimethylacrylamide. After stirring and dissolving, the sulfonated phenolic resin was added to the reactor, along with 1.8 parts by weight of ammonium persulfate. The temperature was raised to 55°C and the reaction was carried out for 4 hours. The mixture was dried at 105°C and pulverized to 100 mesh to obtain component B. 3) Add 50% of component A and 50% of component B into a mixing tank and mix for 1 hour to obtain a high-temperature resistant, anti-collapse, and filtration-reducing agent.

[0062] Comparative Example 1 A high-temperature resistant, anti-collapse, and filtration-reducing agent is only component B of Example 1.

[0063] The preparation steps are as follows: 94 parts by weight of phenol, 320 parts by weight of water, 100 parts by weight of sodium humate, 66 parts by weight of sodium sulfite, and 60 parts by weight of sodium bisulfite were added to a reactor. The temperature was raised to 85°C, and then 208 parts by weight of formaldehyde were added dropwise. After the addition was complete, the temperature was raised to 120°C and the synthesis reaction was carried out for 5 hours to obtain sulfonated phenolic resin. In another reactor, 600 parts by weight of water and 60 parts by weight of sodium hydroxide were added. After the sodium hydroxide dissolved and cooled, 210 parts by weight of AMPS were added, followed by 90 parts by weight of acrylamide and 100 parts by weight of N,N-dimethylacrylamide. After stirring and dissolving, the sulfonated phenolic resin was added to the reactor, along with 1.8 parts by weight of ammonium persulfate. The temperature was raised to 55°C and the reaction was carried out for 4 hours. The mixture was then dried at 105°C and pulverized to 100 mesh to obtain a high-temperature resistant, anti-collapse, and filtration-reducing agent.

[0064] Comparative Example 2 A high-temperature resistant, anti-collapse, and filtration-reducing agent is only component A of Example 1.

[0065] The preparation steps are as follows: 300 parts by weight of asphalt (30% asphaltene, 25% resin, 42% aromatic phenols, and the balance saturated fraction) were crushed into 20-mesh particles and added to a reactor containing 600 parts by weight of kerosene. The mixture was stirred and heated to 35°C to ensure thorough dispersion of the asphalt. The temperature was then raised to 45°C, and 500 parts by weight of sulfur trioxide were added to the reactor. After the addition was complete, the reaction temperature was maintained for 1.5 hours. 100 parts by weight of sodium hydroxide (40% aqueous solution) was added to adjust the pH of the system to 8. The oil layer was allowed to stand and separated, and then recycled. The water layer was dried at 105°C and crushed to 100 mesh to obtain a high-temperature resistant, anti-collapse, and filtration loss reducing agent.

[0066] Comparative Example 3 A high-temperature resistant, anti-collapse, and filtration-reducing agent, which omits the grafted polymer compared to Example 1.

[0067] The preparation steps are as follows: 300 parts by weight of asphalt (30% asphaltenes, 25% resins, 42% aromatic phenols, and the balance saturated fraction) were crushed into 20-mesh particles and added to a reactor containing 600 parts by weight of kerosene. The mixture was stirred and heated to 35°C to ensure thorough dispersion of the asphalt. The temperature was then raised to 45°C, and 500 parts by weight of sulfur trioxide were added to the reactor. After the addition was complete, the reaction temperature was maintained for 1.5 hours. 100 parts by weight of sodium hydroxide (40% aqueous solution) was added to adjust the pH of the system to 8. The oil layer was allowed to stand and separated, and then recycled. The water layer was dried at 105°C and crushed to 100 mesh to obtain component A. 2) Add 94 parts by weight of phenol, 320 parts by weight of water, 100 parts by weight of sodium humate, 66 parts by weight of sodium sulfite, and 60 parts by weight of sodium bisulfite to the reactor, heat to 85°C, and then add 208 parts by weight of formaldehyde dropwise. After the addition is complete, heat to 120°C and carry out the synthesis reaction for 5 hours. Dry at 105°C and pulverize to 100 mesh to obtain component B. 3) Add 45% of component A and 55% of component B into a mixing tank and mix for 1 hour to obtain a high-temperature resistant, anti-collapse, and filtration-reducing agent.

[0068] Comparative Example 4 A high-temperature resistant, anti-collapse, and filtration-reducing agent, which replaces sulfur trioxide with fuming sulfuric acid in Example 1.

[0069] The preparation steps are as follows: 300 parts by weight of asphalt (30% asphaltenes, 25% resins, 42% aromatic phenols, and the balance saturated fraction) were crushed into 20-mesh particles and added to a reactor containing 600 parts by weight of kerosene. The mixture was stirred and heated to 35°C to ensure thorough dispersion of the asphalt. The temperature was then raised to 45°C, and 500 parts by weight of fuming sulfuric acid were added to the reactor. After the addition was complete, the reaction temperature was maintained for 1.5 hours. 100 parts by weight of sodium hydroxide (40% aqueous solution) was added to adjust the pH of the system to 8. The oil layer was allowed to stand and separated, and then recycled. The water layer was dried at 105°C and crushed to 100 mesh to obtain component A. 2) Add 94 parts by weight of phenol, 320 parts by weight of water, 100 parts by weight of sodium humate, 66 parts by weight of sodium sulfite, and 60 parts by weight of sodium bisulfite to a reactor, heat to 85°C, and then add 208 parts by weight of formaldehyde dropwise. After the addition is complete, heat to 120°C and carry out the synthesis reaction for 5 hours to obtain sulfonated phenolic resin. In another reactor, add 600 parts by weight of water and 60 parts by weight of sodium hydroxide. After the sodium hydroxide dissolves and cools, add 210 parts by weight of AMPS, then add 90 parts by weight of acrylamide and 100 parts by weight of N,N-dimethylacrylamide. After stirring and dissolving, add the sulfonated phenolic resin to the reactor, add 1.8 parts by weight of ammonium persulfate, heat to 55°C and react for 4 hours, dry at 105°C, and pulverize to 100 mesh to obtain component B. 3) Add 45% of component A and 55% of component B into a mixing tank and mix for 1 hour to obtain a high-temperature resistant, anti-collapse, and filtration-reducing agent.

[0070] Comparative Example 5 A high-temperature resistant, anti-collapse, sealing and filtration loss reducing agent has a modified asphalt composition compared to Example 1.

[0071] The preparation steps are as follows: 300 parts by weight of asphalt (45% asphaltenes, 15% resins, 37% aromatic phenols, and the balance saturated fraction) were crushed into 20-mesh particles and added to a reactor containing 600 parts by weight of kerosene. The mixture was stirred and heated to 35°C to ensure thorough dispersion of the asphalt. The temperature was then raised to 45°C, and 500 parts by weight of sulfur trioxide were added to the reactor. After the addition was complete, the reaction temperature was maintained for 1.5 hours. 100 parts by weight of sodium hydroxide (40% aqueous solution) was added to adjust the pH of the system to 8. The oil layer was allowed to stand and separated, and then recycled. The water layer was dried at 105°C and crushed to 100 mesh to obtain component A. 2) Add 94 parts by weight of phenol, 320 parts by weight of water, 100 parts by weight of sodium humate, 66 parts by weight of sodium sulfite, and 60 parts by weight of sodium bisulfite to a reactor, heat to 85°C, and then add 208 parts by weight of formaldehyde dropwise. After the addition is complete, heat to 120°C and carry out the synthesis reaction for 5 hours to obtain sulfonated phenolic resin. In another reactor, add 600 parts by weight of water and 60 parts by weight of sodium hydroxide. After the sodium hydroxide dissolves and cools, add 210 parts by weight of AMPS, then add 90 parts by weight of acrylamide and 100 parts by weight of N,N-dimethylacrylamide. After stirring and dissolving, add the sulfonated phenolic resin to the reactor, add 1.8 parts by weight of ammonium persulfate, heat to 55°C and react for 4 hours, dry at 105°C, and pulverize to 100 mesh to obtain component B. 3) Add 45% of component A and 55% of component B into a mixing tank and mix for 1 hour to obtain a high-temperature resistant, anti-collapse, and filtration-reducing agent.

[0072] Comparative Example 6 A high-temperature resistant, anti-collapse, and filtration-reducing agent, compared to the grafted polymer in Example 1, is a binary polymer.

[0073] The preparation steps are as follows: 300 parts by weight of asphalt (30% asphaltenes, 25% resins, 42% aromatic phenols, and the balance saturated fraction) were crushed into 20-mesh particles and added to a reactor containing 600 parts by weight of kerosene. The mixture was stirred and heated to 35°C to ensure thorough dispersion of the asphalt. The temperature was then raised to 45°C, and 500 parts by weight of sulfur trioxide were added to the reactor. After the addition was complete, the reaction temperature was maintained for 1.5 hours. 100 parts by weight of sodium hydroxide (40% aqueous solution) was added to adjust the pH of the system to 8. The oil layer was allowed to stand and separated, and then recycled. The water layer was dried at 105°C and crushed to 100 mesh to obtain component A. 2) Add 94 parts by weight of phenol, 320 parts by weight of water, 100 parts by weight of sodium humate, 66 parts by weight of sodium sulfite, and 60 parts by weight of sodium bisulfite to a reactor, heat to 85°C, and then add 208 parts by weight of formaldehyde dropwise. After the addition is complete, heat to 120°C and carry out the synthesis reaction for 5 hours to obtain sulfonated phenolic resin. In another reactor, add 600 parts by weight of water and 60 parts by weight of sodium hydroxide. After the sodium hydroxide dissolves and cools, add 210 parts by weight of AMPS, then add 90 parts by weight of acrylamide. After stirring and dissolving, add the sulfonated phenolic resin to the reactor, add 1.8 parts by weight of ammonium persulfate, heat to 55°C and react for 4 hours, dry at 105°C, and pulverize to 100 mesh to obtain component B. 3) Add 45% of component A and 55% of component B into a mixing tank and mix for 1 hour to obtain a high-temperature resistant, anti-collapse, and filtration-reducing agent.

[0074] Test Example 1 (1) High temperature and high pressure filtration loss The smaller the filtration loss, the better the filtration loss reduction effect and the better the temperature resistance.

[0075] Preparation of base slurry: Take 350 mL of 15% saline solution, add 21.0 g of bentonite for the test slurry and 16.0 g of evaluation soil, and stir at high speed for 20 min. Sealed curing at (25±1)℃ for 24 hours. Base slurry performance test: Take a portion of base slurry and stir at high speed for 5 minutes. Measure the water loss under pressure according to GB / T16783.1. If it is between (100±10) mL, otherwise adjust the amount of soil added.

[0076] Sample slurry: Take two portions of base slurry and add 10.5g of the sample to each portion under high-speed stirring. Stir at high speed for 10 minutes, then add 5mL of 20% sodium hydroxide solution and stir at high speed for a total of 20 minutes, interrupting at least twice to scrape off the sample adhering to the cup wall. Transfer the sample slurry to an aging tank and roll it at 200℃ for 16 hours. Remove the aging tank, cool and depressurize it, open it, pour out the sample slurry, and stir at high speed for 5 minutes (add a few drops of defoamer if there are bubbles). Determine its apparent viscosity and filtration loss at 140℃ and high pressure according to GB / T16783.1.

[0077] (2) Shale recovery rate The core sample used was from the 2987-meter core sample of Well Hongye 7. The core recovery rate with distilled water was 18.2%. The higher the core recovery rate, the better the anti-collapse properties of the product.

[0078] Sample recovery rate: Measure 350 mL of distilled water, add 10.5 g of sample, stir to dissolve completely, pour into an aging tank, add 50.0 g of core particles, and seal tightly. Place the aging tank containing the sample in a roller furnace and roll at 150℃ for 16 h. Remove the aging tank and cool to room temperature. Pour all the liquid and rock sample from the tank onto a sieve with a mesh size of 0.425 mm, and wash with tap water for 1 min. Place the remaining rock sample on a constant temperature oven at 105±3℃ and dry for 4 h. Remove, cool, and then weigh (accurate to 0.01 g). Shale recovery rate: (test slurry recovery amount / 50 g) 100%.

[0079] (3) Relative expansion rate The lower the relative expansion, the better the anti-collapse effect and the stronger the wellbore stability.

[0080] Weigh 5.00g of the sample and add it to a beaker containing 100mL of distilled water. Stir on a magnetic stirrer to dissolve for 1 hour. Weigh 10.00g of bentonite (dried at (105±2)℃ and cooled in a desiccator for 30 minutes) for the expansion test. Place this bentonite into the measuring cylinder of a shale dilatometer. Slowly pressurize the cylinder to 4.0MPa using a pressure machine. After the pressure stabilizes (remaining essentially constant for 10 seconds), maintain this pressure for 5 minutes to obtain the test core. Install the measuring cylinder containing the core onto the shale dilatometer. Fill the cylinder with the prepared sample solution. Start the instrument and measure the linear expansion over 8 hours. Simultaneously, perform a blank test using distilled water. The expansion height of the core in the blank test should be greater than or equal to 8mm. Relative expansion rate: Expansion of the sample / Expansion of distilled water. 100%.

[0081] The test results are recorded in Table 1.

[0082] Table 1 Performance test record of different samples

[0083] As can be seen from Table 1, Examples 1, 2, and 3 not only have low apparent viscosity, high-temperature and high-pressure filtration loss, and relative expansion reduction rate, but also high shale recovery rate, demonstrating good high-temperature filtration loss reduction effect, shale stabilization effect, and wellbore stabilization effect. Comparative Example 1 used only component B, and the filtration loss, shale recovery rate, and relative expansion rate of the product were all much lower than those of Example 1, indicating that component A plays a very important role in the product. Comparative Example 2 used only component A, and although the shale recovery rate was slightly lower than that of Example 1, the high-temperature and high-pressure filtration loss and relative expansion reduction rate were significantly increased, and it also thickened severely in brine. The data from Comparative Examples 1 and 2 demonstrate that components A and B have a synergistic effect, and the combined effect is worse than the effect of using them alone. In Comparative Example 3, no polymer was introduced. Although the viscosity was slightly lower than in the previous example, the high-temperature, high-pressure filtration loss and relative expansion rate were higher than in Example 1, while the shale recovery rate was slightly lower. This indicates that the addition of the polymer improved the product's filtration loss reduction, shale inhibition effect, and wellbore stability, thus improving the product's performance. In Comparative Example 4, fuming sulfuric acid was used as the sulfonating agent for component A. Its high-temperature, high-pressure filtration loss and relative expansion rate were higher than in Example 1, while the shale recovery rate was lower. This shows that using sulfur trioxide as the sulfonating agent has a good performance-enhancing effect on the product, highlighting the importance of the sulfonating agent selected in this invention. In Comparative Example 5, the asphalt for component A was selected from asphalt with 45% asphaltenes, 15% resins, and 37% aromatic phenols. Its high-temperature, high-pressure filtration loss and relative expansion rate were higher than in Example 1, while the shale recovery rate was lower. This indicates that the type of asphalt has a certain impact on product performance and also highlights the importance of selecting suitable asphalt. In Comparative Example 6, the ternary polymer in component B was replaced with a binary polymer, and N,N-dimethylacrylamide was removed. The experimental results show that the high-temperature and high-pressure filtration loss and relative expansion rate both increased, while the shale recovery rate decreased. The performance was significantly worse than that of Example 1, which demonstrates that the grafted ternary polymer is better than the binary polymer, highlighting the important role of the ternary polymer in this invention.

[0084] Test Example 2 Three commercially available treatment agents, FT-401, SPNH, and SMP-Ⅰ, were tested according to the method in Test Example 1. The test results are recorded in Table 2.

[0085] Table 2 Performance Test Records of Example 1 and Commercially Available Treatment Agent

[0086] As shown in Table 2, FT-401 has a lower relative expansion and a higher cuttings recovery rate, but it still does not achieve the effect of Example 1. Furthermore, its high-temperature, high-pressure filtration loss reaches 67.2 mL, far exceeding the 16.2 mL of Example 1. While SPNH shows some effect in reducing filtration loss, shale recovery rate, and relative expansion rate, its overall effect is far lower than that of Example 1. Although SMP-Ⅰ has a good effect in reducing filtration loss, its filtration loss is also slightly higher than that of Example 1, and its relative expansion rate is much higher, while its shale recovery rate is far lower. The three commonly used treatment agents are far less effective than Example 1 in reducing filtration loss and stabilizing the wellbore, demonstrating the good performance of this invention.

[0087] In summary, Example 1 demonstrates excellent filtration loss reduction in brine slurry at 200°C, forming a dense mud cake on the wellbore and preventing filtrate from entering the formation. Its high shale recovery rate indicates that the product inhibits shale dispersion and expansion, preventing cuttings from dispersing in the drilling fluid and affecting its performance. The low relative expansion rate demonstrates the product's effective wellbore protection, reducing mud cake permeability to prevent filtrate from entering the formation and minimizing the impact of filtrate on the shale, thus preventing expansion and stabilizing the wellbore. This product comprehensively improves mud performance, reduces filtration loss, enhances sealing properties, and increases inhibition, thereby comprehensively stabilizing the wellbore and resolving wellbore instability issues. Furthermore, the product has been applied in more than 10 wells, including Lu203H11-6, Lu203H11-7, Weiye 25-5, Weiye 25-6, Yang101H37-1, Yang101H37-2, and Yang101H37-3, demonstrating good wellbore stability and ensuring the progress of drilling operations in the area.

[0088] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made 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. A high-temperature resistant, anti-collapse, plugging, and filtration loss reducing agent, comprising sulfonated asphalt and modified sulfonated phenolic resin, wherein the mass ratio of the sulfonated asphalt to the modified sulfonated phenolic resin is (40~50):(50~60). The sulfonated asphalt is obtained by sulfonating asphalt, and the sulfonating agent is sulfur trioxide; by mass percentage, the asphalt includes 25-35% asphaltenes, 20-40% resins and 20-45% aromatic phenols. The modified sulfonated phenolic resin is a humic acid-polymer grafted sulfonated phenolic resin; the grafted polymer in the modified sulfonated phenolic resin is a ternary polymer of 2-acrylamide-2-methylpropanesulfonic acid, acrylamide and N,N-dimethylacrylamide.

2. The high-temperature resistant, anti-collapse, sealing, and filtration loss reducing agent according to claim 1, characterized in that, The sulfonation includes: Asphalt, organic solvent and sulfur trioxide are mixed and then subjected to sulfonation reaction; the sulfonation reaction temperature is 40~50℃ and the reaction time is 1.5~2h. The pH of the system after the sulfonation reaction is adjusted to 7-9, and then the organic solvent is separated to obtain sulfonated asphalt.

3. The high-temperature resistant, anti-collapse, sealing, and filtration loss reducing agent according to claim 2, characterized in that, The mass ratio of the asphalt, organic solvent and sulfur trioxide, by mass parts, is (250~350):(400~600):(400~600).

4. The high-temperature resistant, anti-collapse, sealing, and filtration loss reducing agent according to claim 1, characterized in that, The modified sulfonated phenolic resin contains 5-10% grafted humic acid by mass.

5. The high-temperature resistant, anti-collapse, sealing, and filtration loss reducing agent according to claim 1, characterized in that, The modified sulfonated phenolic resin contains 50-60% by mass of grafted polymer.

6. The high-temperature resistant, anti-collapse, sealing, and filtration loss reducing agent according to claim 1, characterized in that, The mass ratio of 2-acrylamide-2-methylpropanesulfonic acid, acrylamide and N,N-dimethylacrylamide is (190~210):(80~100):(80~120).

7. The high-temperature resistant, anti-collapse, sealing, and filtration loss reducing agent according to claim 1, 4, 5, or 6, characterized in that, The preparation of the modified sulfonated phenolic resin includes the following steps: Phenol, water, humate, sulfite, bisulfite and formaldehyde aqueous solution are first mixed and then subjected to a synthesis reaction to obtain humic acid grafted sulfonated phenolic resin; the synthesis reaction temperature is 110~130℃ and the synthesis reaction time is 4~6h. A second sulfonated phenolic resin grafted with humic acid is mixed with an aqueous solution of sodium hydroxide, 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, N,N-dimethylacrylamide, an initiator, and the humic acid grafted sulfonated phenolic resin and then subjected to a grafting reaction to obtain a modified sulfonated phenolic resin; the grafting reaction temperature is 50~60℃ and the grafting reaction time is 3~5h.

8. The high-temperature resistant, anti-collapse, sealing, and filtration loss reducing agent according to claim 7, characterized in that, The humate is one or both of sodium humate and sodium fulvate.

9. The high-temperature resistant, anti-collapse, sealing, and filtration loss reducing agent according to claim 7, characterized in that, The mass ratio of phenol, sulfite and bisulfite is (80~120):(60~70):(55~65).

10. The preparation method of the high-temperature resistant, anti-collapse, plugging, and filtration loss reducing agent according to any one of claims 1 to 9, characterized in that, include: The modified sulfonated phenolic resin is mixed with the sulfonated asphalt to obtain a high-temperature resistant, anti-collapse, plugging, and filtration loss reducing agent.

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