CN115558477A - Water-based drilling fluid for ultra-large displacement well - Google Patents

Water-based drilling fluid for ultra-large displacement well Download PDF

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CN115558477A
CN115558477A CN202211107763.7A CN202211107763A CN115558477A CN 115558477 A CN115558477 A CN 115558477A CN 202211107763 A CN202211107763 A CN 202211107763A CN 115558477 A CN115558477 A CN 115558477A
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drilling fluid
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CN115558477B (en
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由福昌
许明标
可点
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Jingzhou Jiahua Technology Co ltd
Yangtze University
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Jingzhou Jiahua Technology Co ltd
Yangtze University
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    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/02—Well-drilling compositions
    • C09K8/04—Aqueous well-drilling compositions
    • C09K8/06—Clay-free compositions
    • C09K8/12—Clay-free compositions containing synthetic organic macromolecular compounds or their precursors
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
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    • C08G73/024—Polyamines containing oxygen in the form of ether bonds in the main chain
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
    • C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
    • C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
    • C08G73/1092—Polysuccinimides
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    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
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    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/02—Well-drilling compositions
    • C09K8/04—Aqueous well-drilling compositions
    • C09K8/06—Clay-free compositions
    • C09K8/08—Clay-free compositions containing natural organic compounds, e.g. polysaccharides, or derivatives thereof
    • C09K8/10—Cellulose or derivatives thereof
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    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/50—Compositions for plastering borehole walls, i.e. compositions for temporary consolidation of borehole walls
    • C09K8/504—Compositions based on water or polar solvents
    • C09K8/506—Compositions based on water or polar solvents containing organic compounds
    • C09K8/508—Compositions based on water or polar solvents containing organic compounds macromolecular compounds
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    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/52—Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning
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    • C09K2208/00—Aspects relating to compositions of drilling or well treatment fluids
    • C09K2208/34—Lubricant additives

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Abstract

The invention provides a water-based drilling fluid for an ultra-large displacement well, and relates to the technical field of oil field chemistry of petroleum drilling engineering. The ultra-large displacement well water-based drilling fluid is aged at different densities and different temperatures: the rheological property is good, the dynamic-plastic ratio and the readings of 6 turns and 3 turns are large, rock cleaning and sand carrying of the ultra-large displacement well are facilitated, and a rock debris bed is prevented from being generated in a horizontal section; the method has the characteristics of low API (American Petroleum institute) filtration loss and low high-temperature and high-pressure water loss, and is high in rolling recovery rate and strong in inhibition, so that the stability of the well wall in the operation process is kept; the extreme pressure lubrication coefficient and the average friction coefficient are equivalent to those of oil base, and the wear resistance is superior to that of oil base drilling fluid, which shows that the ultra-large displacement water-based drilling fluid has good performance of reducing friction torque, and can reduce the phenomena of holding torque, drilling sticking and the like.

Description

Water-based drilling fluid for ultra-large displacement well
Technical Field
The invention relates to the technical field of oil field chemistry of petroleum drilling engineering, in particular to a water-based drilling fluid.
Background
The ultra-large displacement well (the operating well with the water-to-vertical ratio of more than 2 or the horizontal displacement distance of more than 2000 m) with the long horizontal section can furthest improve the contact area between a well bore and a reservoir, greatly improve the single well yield of an oil-gas well, reduce the oil-gas exploitation cost, is widely applied to the exploration and development of oil-gas resources of a plurality of oil fields at home and abroad at present, and becomes one of important technical means for efficiently developing unconventional oil-gas reservoirs such as a compact gas low-permeability oil reservoir, a shale gas oil reservoir and the like and offshore oil reservoir margins. The oil-based drilling fluid has excellent lubricating, inhibiting and pollution-resisting properties and the like, has strong rheological property regulation and control capability, and can effectively reduce friction resistance torque in a drilling process, reduce invasion of oily filtrate to stratum rocks and ensure the lubricating anti-blockage capability and well wall stability of an operating well in the application process of an ultra-large displacement well. However, due to increased environmental demands, as well as the need for low drilling costs and ease of handling in the field, the use of oil-based drilling fluids is increasingly limited.
The water-based drilling fluid has low cost, simple treatment process of wastes such as drilling cuttings and the like, and relatively small toxic and side effects on the environment, and can effectively overcome the defects of the oil-based drilling fluid. However, the application of the current water-based drilling fluid in an ultra-large displacement well has the problems of insufficient lubricity and inhibitive performance and poor well cleaning condition. Therefore, the research on the ultra-large displacement well water-based drilling fluid needs to improve the lubricating, drag-reducing and torque-reducing performances of the water-based drilling fluid, optimize the rheological performance of the water-based drilling fluid and improve the system inhibition performance.
The invention patent with the authorization number of CN103952128B discloses a weak gel solid-free water-based drilling fluid suitable for extended reach wells and horizontal wells, and the drilling fluid formula provided by the scheme is as follows: calculated by 100 percent of weight, 0.5 to 1 percent of coating agent, 0.5 to 1 percent of flow pattern regulator, 2 to 6 percent of filtrate reducer, 0.5 to 1 percent of inhibitor, 1 to 6 percent of lubricant, 0.2 to 1 percent of alkaline pH regulator, 0.2 to 0.5 percent of corrosion inhibitor, 5 to 40 percent of salt and the balance of water. The weak gel solid-free crystal drilling fluid has high viscosity and good temperature resistance at a low shear rate, and has strong inhibition and lubricity. However, the system is only suitable for extended reach wells under low density conditions, and the high-temperature and high-pressure filtration loss is large, which is not favorable for stabilizing the well wall of the operation well.
The invention patent with the application number of CN202110906457.9 discloses a low-friction water-based drilling fluid which comprises the following preparation raw materials in parts: water: 75-90 parts; polyphosphate water solution: 10-25 parts; alkalinity regulator: 0.1 to 2.0 portions; fluid loss additive: 1.0-4.0 parts; rheology modifier: 0.1 to 0.6 portion; anti-collapse plugging agent: 1.0-3.5 parts; inhibitor (B): 1.0-3.5 parts; barite: 0 to 100 portions. The low-friction water-based drilling fluid disclosed by the invention is not added with an oily or aqueous lubricant, but uses a polyphosphate water solution with super-strong lubricity as a base fluid to realize the lubricating property which is comparable to that of an oil-based drilling fluid. However, the low-friction water-based drilling fluid only has lubricating and wear-resisting properties comparable to those of oil-based drilling fluid, influences the stability of the well wall of the drilling fluid closely related to the horizontal extension distance of the ultra-large displacement well, and does not evaluate the properties of rock cleaning, sand carrying and the like.
The invention patent with the application number of CN107955589A discloses a cellulose nanofiber and clay-phase-free water-based drilling fluid containing the same, wherein the volume of 1L of water is taken as a reference, and the content of the cellulose nanofiber is 1-30 g; the content of the filtrate reducer is 20-40 g; the content of the shale inhibitor is 10-30 g; the content of the high-temperature stabilizer is 1-10 g; the content of the lubricant is 20-30 g; the content of the weighting material in each liter of the clay-phase-free water-based drilling fluid is 100-2000 g. The scheme has good and stable rheological property under the conditions of high temperature of 180 ℃ and before and after aging, the dynamic-plastic ratio reaches more than 0.5, the drilling fluid has strong shearing dilutability and thixotropy, has the characteristic of 'quick weak gel', and is beneficial to improving the rock carrying efficiency of the drilling fluid in the drilling process of extended reach wells and horizontal wells. However, the lubricating, drag-reducing, anti-collapse performance of the water-based drilling fluid is not evaluated, and whether the water-based drilling fluid is suitable for the operation of the ultra-large displacement well cannot be determined.
In conclusion, although a great amount of high-lubrication, strong-inhibition, strong-plugging and high-efficiency water-based drilling fluid is reported in the current published patents and scientific papers, most of the water-based drilling fluids cannot simultaneously meet the problems of lubrication anti-blocking, well cleaning and well wall stability of the ultra-large displacement well.
Disclosure of Invention
The invention aims to provide a water-based drilling fluid which can simultaneously solve the problems of lubrication and blockage prevention of a super-large displacement well, well cleaning and well wall stability and realize safe and efficient super-large displacement well operation of the water-based drilling fluid.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a water-based drilling fluid, which comprises a water-based fluid and the following components in percentage by mass:
alkaline pH adjuster: 0.2 to 1 percent;
fluid loss additive: 1 to 2 percent;
coating agent: 0.5 to 1 percent;
weighting agent: 0 to 100 percent;
flow pattern regulator: 0.2 to 1 percent;
polyamine inhibitors: 1 to 2 percent;
multifunctional lubricating drag reducer: 10 to 20 percent;
the polyamine inhibitor is an amino polymer obtained by polymerizing diethylene glycol bis (3-aminopropyl) ether and maleic anhydride;
the multifunctional lubricating drag reducer comprises, by mass, 200 parts of modified polyaspartic acid 60-70 parts, polyol phosphate 30-40 parts and water 100 parts;
the preparation of the modified polyaspartic acid comprises the following steps: mixing water, polysuccinimide powder, a first sodium hydroxide solution and N, N-dimethyl-1, 3-propane diamine, carrying out ring-opening polymerization at 70-80 ℃, cooling to 25-35 ℃, adding a second sodium hydroxide solution into the obtained product system, and hydrolyzing to obtain the modified polyaspartic acid.
Preferably, the water-based liquid is fresh water or seawater.
Preferably, the alkaline pH adjuster is one or more of sodium hydroxide, sodium carbonate, potassium hydroxide and magnesium hydroxide.
Preferably, the alkaline pH regulator comprises 30-40 parts of sodium hydroxide, 30-40 parts of sodium carbonate and 20-40 parts of magnesium hydroxide by mass of 100 parts of the alkaline pH regulator.
Preferably, the fluid loss additive is one or more of carboxymethyl starch, hydroxyethyl starch, sodium carboxymethyl cellulose and polyanionic cellulose.
Preferably, the coating agent is one or two of a zwitterionic polymer coating agent and partially hydrolyzed polyacrylamide.
Preferably, the flow pattern modifier is one or more of xanthan gum, guar gum, konjac flour, sesbania powder and artemisia gum.
Preferably, the molar ratio of the diethylene glycol bis (3-aminopropyl) ether to the maleic anhydride is (1-10): (1-10).
Preferably, the weighting agent is barite.
Preferably, the ring-opening polymerization time is 3 to 5 hours.
The invention provides a water-based drilling fluid, which comprises a water-based fluid and the following components in percentage by mass: alkaline pH adjuster: 0.2 to 1 percent; fluid loss additive: 1 to 2 percent; coating agent: 0.5 to 1 percent; weighting agent: 0 to 100 percent; flow pattern regulator: 0.2 to 1 percent; polyamine inhibitors: 1 to 2 percent; multifunctional lubricating drag reducer: 10 to 20 percent; the polyamine inhibitor is an amino polymer obtained by polymerizing diethylene glycol bis (3-aminopropyl) ether and maleic anhydride; the multifunctional lubricating drag reducer comprises, by mass, 200 parts of modified polyaspartic acid 60-70 parts, polyol phosphate 30-40 parts and water 100 parts; the preparation of the modified polyaspartic acid comprises the following steps: mixing water, polysuccinimide powder, a first sodium hydroxide solution and N, N-dimethyl-1, 3-propane diamine, carrying out ring-opening polymerization at 70-80 ℃, cooling to 25-35 ℃, adding a second sodium hydroxide solution into the obtained product system, and hydrolyzing to obtain the modified polyaspartic acid.
The multifunctional lubricating drag reducer is prepared by compounding modified polyaspartic acid and polyalcohol phosphate ester, has low biological toxicity, excellent lubricating property, certain plugging property and inhibiting function, can reduce the dosage of a system inhibitor and a plugging agent, and reduces the field application and maintenance difficulty of drilling fluid; specifically, the method comprises the following steps: the polyaspartic acid has strong water solubility, no toxicity, no pollution and strong biodegradability, lone pair electrons on N and O atoms in the molecule of a polymerization product can be combined with orbits such as Fe and the like to form a complex to be adsorbed on the surface of metal, and a compact adsorption film is formed to play an extreme pressure lubrication role; the amido, carboxyl, amido and the like of the modified polyaspartic acid can also form a nonpolar oil film on the surface of the clay, so that the inhibition performance of a drilling fluid system is improved; the macromolecular chain of the polymer can form a space network structure by stretching in water, thereby playing a role in auxiliary plugging; the modified polyaspartic acid increases the water solubility and molecular weight, improves the lubrication, inhibition and blocking effects, and further improves the extreme pressure lubrication wear resistance of the multifunctional lubrication drag reducer by compounding with polyol phosphate.
The water-based drilling fluid has better rheological property, inhibition property and anti-wear and anti-drag property under the coordination action of the flow pattern regulator, the polyamine inhibitor and the lubricating and drag-reducing agent, and can solve the problems of high difficulty in cleaning a borehole of an ultra-large displacement well, high requirement on the stability of the borehole wall, high friction and torque and the like.
In addition, the water-based drilling fluid has wider density by adjusting the addition amount of the weighting agent, and the density can reach 1.5g/cm at most 3 Meanwhile, the decomposition of each component is not obvious at high temperature, the temperature application range is that the application temperature is up to 150 ℃.
Drawings
FIG. 1 is a wear scar map for example 1;
FIG. 2 is a wear scar map for example 2;
FIG. 3 is a wear scar map for example 3;
FIG. 4 is a wear scar map for example 4;
FIG. 5 is a wear scar map for example 5;
FIG. 6 is a wear scar map for example 6;
FIG. 7 is a wear scar map for example 7;
FIG. 8 is a wear scar map for example 8;
FIG. 9 is a wear scar map for comparative example 1;
FIG. 10 is a wear scar map for comparative example 2;
fig. 11 is a wear scar map of comparative example 3.
Detailed Description
The invention provides a water-based drilling fluid, which comprises a water-based fluid and the following components in percentage by mass:
alkaline pH adjuster: 0.2 to 1 percent;
fluid loss additive: 1 to 2 percent;
coating agent: 0.5 to 1 percent;
weighting agent: 0 to 100 percent;
flow pattern regulator: 0.2 to 1 percent;
polyamine inhibitors: 1 to 2 percent;
multifunctional lubricating drag reducer: 10 to 20 percent;
the polyamine inhibitor is an amino polymer obtained by polymerizing diethylene glycol bis (3-aminopropyl) ether and maleic anhydride;
the multifunctional lubricating drag reducer comprises, by mass, 200 parts of modified polyaspartic acid 60-70 parts, polyol phosphate 30-40 parts and water 100 parts;
the preparation of the modified polyaspartic acid comprises the following steps: mixing water, polysuccinimide powder, a first sodium hydroxide solution and N, N-dimethyl-1, 3-propane diamine, carrying out ring-opening polymerization at 70-80 ℃, cooling to 25-35 ℃, adding a second sodium hydroxide solution into the obtained product system, and hydrolyzing to obtain the modified polyaspartic acid.
In the present invention, the starting materials used are all commercially available products well known in the art, unless otherwise specified.
The water-based drilling fluid provided by the invention comprises a water-based fluid. In the present invention, the water-based fluid is preferably fresh water or seawater.
Based on the mass of the water-based fluid, the water-based drilling fluid provided by the invention comprises an alkaline pH regulator which accounts for 0.2-1% of the water-based fluid, preferably 0.3-0.8%, and more preferably 0.4-0.6%. In the present invention, the alkaline pH adjuster is one or more of sodium hydroxide, sodium carbonate, potassium hydroxide, and magnesium hydroxide, and more preferably sodium hydroxide, sodium carbonate, and magnesium hydroxide. The alkaline pH regulator is preferably composed of 30-40 parts of sodium hydroxide, 30-40 parts of sodium carbonate and 20-40 parts of magnesium hydroxide by mass based on 100 parts of the alkaline pH regulator. In the invention, the sodium hydroxide and sodium carbonate buffer can provide a stable alkaline condition for the system, and the magnesium hydroxide can still maintain a good alkaline environment under a high-temperature condition, so that the problem that the alkalinity of the system is reduced too fast under the high-temperature condition to influence the stability of the drilling fluid material is solved.
The water-based drilling fluid provided by the invention comprises a filtrate loss reducer accounting for 1-2% of the water-based fluid, preferably 1.2-1.8%, and more preferably 1.4-1.6%. In the present invention, the fluid loss additive is preferably one or more of carboxymethyl starch, hydroxyethyl starch, sodium carboxymethyl cellulose and polyanionic cellulose, more preferably carboxymethyl starch and polyanionic cellulose. The fluid loss agent is preferably composed of 45 parts of carboxymethyl starch and 55 parts of polyanionic cellulose by mass of 100 parts of the fluid loss agent. According to the invention, the fluid loss additive can reduce the fluid loss of the drilling fluid and improve the quality of mud cakes.
The water-based drilling fluid provided by the invention comprises a coating agent accounting for 0.5-1% of the water-based fluid, preferably 0.6-0.9%, and more preferably 0.7-0.8%. In the present invention, the coating agent is preferably one or both of a zwitterionic polymer-based coating agent and a partially hydrolyzed polyacrylamide. The invention has no special requirements on the specific types of the zwitterionic polymer coating agents, and can be FA367 or VISPLUS; the invention has no special requirements on the specific types of the partially hydrolyzed polyacrylamide, and can be PF-PLUS, PF-PLH and JH-PLUS. In the invention, the coating agent has the functions of improving rheological parameters of the drilling fluid, improving the shearing and diluting capability, reducing the filtration loss and coating drill cuttings.
The water-based drilling fluid provided by the invention comprises a weighting agent accounting for 0-100% of the water-based fluid. The amount of weighting agent added can be adjusted by one skilled in the art according to the density requirements. In the present invention, the weighting agent is preferably barite; the grain size of the barite is preferably 200 to 1000 meshes, more preferably 300 to 800 meshes, and even more preferably 500 to 600 meshes.
The water-based drilling fluid provided by the invention comprises a flow pattern regulator accounting for 0.2-1% of the water-based fluid, preferably 0.3-0.9%, and more preferably 0.4-0.8%. In the present invention, the flow pattern modifier is preferably one or more of xanthan gum, guar gum, konjac flour, sesbania flour and artemisia gum; when the flow pattern regulator is a plurality of the substances, the invention has no special requirements on the mixture ratio of the substances and can be used in any mixture ratio. In the invention, the flow pattern regulator is used for regulating the rheological property of the drilling fluid and improving the dynamic-plastic ratio.
The water-based drilling fluid provided by the invention comprises 1-2% of polyamine inhibitor in water-based fluid, preferably 1.2-1.8%, more preferably 1.4-1.6%. In the invention, the polyamine inhibitor is an amine-based polymer obtained by polymerizing diethylene glycol bis (3-aminopropyl) ether and maleic anhydride; the mol ratio of the diethylene glycol bis (3-aminopropyl) ether to the maleic anhydride is preferably (1-10): (1 to 10), more preferably (1 to 10): (3-7); the polymerization temperature is preferably 125-135 ℃, and the time is preferably 3-5 h. The method for preparing the polyamine inhibitor is not particularly required in the present invention, and a preparation method well known in the art can be adopted. In the present invention, the method for preparing the polyamine inhibitor preferably comprises the steps of: adding diethylene glycol bis (3-aminopropyl) ether into a four-neck round-bottom flask, placing the four-neck round-bottom flask into a constant-temperature oil bath, starting stirring, and introducing nitrogen to remove oxygen; after the temperature is raised to 60 ℃, slowly adding maleic anhydride, and controlling the temperature in the flask to be not more than 65 ℃ by controlling the adding speed; after the feeding is finished, introducing nitrogen again, sealing the flask opening, and keeping the temperature for 30min; slowly raising the temperature to 125-135 ℃, maintaining the reaction temperature of 125-135 ℃ for polymerization for 3-5 h, and then naturally cooling to normal temperature to obtain the polyamine inhibitor.
The polyamine inhibitor can improve the inhibition performance of the drilling fluid and prevent the shale formation from hydrating.
The water-based drilling fluid provided by the invention comprises 10-20% of multifunctional lubricating drag reducer in water-based fluid, preferably 12-18%, and more preferably 14-16%. In the invention, the multifunctional lubricating drag reducer comprises 60-70 parts of modified polyaspartic acid, 30-40 parts of polyol phosphate and 100 parts of water by mass of 200 parts.
In the present invention, the preparation of the modified polyaspartic acid preferably comprises the steps of: mixing water, polysuccinimide powder, a first sodium hydroxide solution and N, N-dimethyl-1, 3-propane diamine, carrying out ring-opening polymerization at 70-80 ℃, cooling to 25-35 ℃, adding a second sodium hydroxide solution into the obtained product system, and hydrolyzing to obtain the modified polyaspartic acid.
In the invention, the water is preferably deionized water, and the mass ratio of the water to the polysuccinimide powder is preferably 100 (10-20); the mass concentration of the first sodium hydroxide solution is preferably 5%; the mass ratio of the first sodium hydroxide solution to N, N-dimethyl-1, 3-propanediamine is preferably (10 to 15): (5-8); the mass ratio of the polysuccinimide powder to the N, N-dimethyl-1, 3-propanediamine is preferably (10 to 20): (5-8). In the present invention, the first sodium hydroxide solution functions to provide an alkaline environment.
In the present invention, mixing water, polysuccinimide powder, the first sodium hydroxide solution and N, N-dimethyl-1, 3-propanediamine preferably comprises: mixing water and polysuccinimide powder to obtain a suspension; dissolving N, N-dimethyl-1, 3-propane diamine into a first sodium hydroxide solution to obtain a dissolved solution; and heating the solution to 70-80 ℃, and adding the suspension into the obtained solution.
In the present invention, the time for the ring-opening polymerization is preferably 3 to 5 hours.
In the ring-opening polymerization process, polysuccinimide is subjected to ring opening and then polymerized with N, N-dimethyl-1, 3-propane diamine.
After the ring-opening polymerization is completed, the temperature is reduced to 25-35 ℃, and a second sodium hydroxide solution is added into the obtained product system for hydrolysis.
In the present invention, the mass concentration of the second sodium hydroxide solution is preferably 20%; the mass ratio of the second sodium hydroxide solution to the polysuccinimide powder is preferably (10 to 20): (10-20). In the present invention, the second sodium hydroxide solution functions to promote hydrolysis. In the present invention, the hydrolysis is preferably performed under stirring, and the hydrolysis time is preferably 0.5 to 1 hour.
After the hydrolysis is finished, the invention preferably further comprises the steps of naturally cooling the hydrolysate system to normal temperature, adding hydrochloric acid for neutralization to neutrality, dripping into absolute ethyl alcohol, stirring to separate out a precipitate, washing the obtained precipitate with acetone, and drying to obtain the modified polyaspartic acid.
The polyaspartic acid has strong water solubility, no toxicity, no pollution and strong biodegradability, lone pair electrons on N and O atoms in the molecule of a polymerization product can be combined with orbits such as Fe and the like to form a complex to be adsorbed on the surface of metal, and a layer of compact adsorption film is formed to play a role in extreme pressure lubrication; the amide group, the carboxyl group, the amino group and the like can also form a nonpolar oil film on the surface of the clay, so that the inhibition performance of a drilling fluid system is improved; the macromolecular chain of the polymer can form a space network structure by stretching in water, thereby playing a role in auxiliary plugging; the modified polyaspartic acid increases the water solubility and molecular weight, improves the lubricating, inhibiting and blocking effects, and further improves the extreme pressure lubricating and wear-resisting properties of the multifunctional lubricating drag reducer by compounding with the polyol phosphate.
The preparation method of the water-based drilling fluid has no special requirements, and the water-based drilling fluid can be prepared by uniformly mixing by adopting a conventional preparation method.
The water-based drilling fluids provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of the invention.
Example 1
The water-base drilling fluid for very large displacement well consists of water, alkaline pH regulator, filtrate reducer, coating agent, flow pattern regulator, polyamine inhibitor and multifunctional lubricating drag reducer;
the weight percentage of each component in water is as follows:
water: 100;
alkaline pH adjuster: 0.5 percent;
fluid loss additive: 1.0 percent;
coating agent: 0.6 percent;
weighting agent: 0;
flow pattern regulator: 0.4 percent;
polyamine inhibitors: 1.2 percent;
multifunctional lubricating drag reducer: 15 percent;
the water is fresh water;
wherein the alkaline pH regulator comprises 40 parts of sodium hydroxide, 40 parts of sodium carbonate and 20 parts of magnesium hydroxide by 100 parts by weight;
the fluid loss additive comprises 50 parts of carboxymethyl starch (CMS) and 50 parts of polyanionic cellulose (PAC) by 100 parts by weight;
the coating agent is partially hydrolyzed polyacrylamide;
the flow pattern regulator comprises 50 parts of xanthan gum and 50 parts of guar gum by 100 parts by weight;
the polyamine inhibitor is an amino polymer obtained by polymerizing diethylene glycol bis (3-aminopropyl) ether and maleic anhydride;
the preparation steps of the polyamine inhibitor are as follows:
firstly, adding 50 parts of diethylene glycol bis (3-aminopropyl) ether into a four-neck round-bottom flask, placing the four-neck round-bottom flask into a constant-temperature oil bath, starting stirring, and introducing nitrogen to remove oxygen; after the temperature is raised to 60 ℃, 25 parts of maleic anhydride is slowly added, and the temperature in the flask is controlled not to exceed 65 ℃ by controlling the adding speed; after the feeding is finished, introducing nitrogen again, sealing the flask opening, and keeping the temperature for 30min; after slowly raising the temperature to 130 ℃, maintaining the reaction temperature of 130 ℃ and keeping the temperature for 4h. Then naturally cooling to normal temperature to obtain the polyamine inhibitor.
The multifunctional lubricating drag reducer comprises, by weight, 200 parts of water, 60 parts of modified polyaspartic acid and 40 parts of polyol phosphate;
the preparation steps of the modified polyaspartic acid are as follows:
firstly, 100 parts of deionized water and 15 parts of polysuccinimide powder are added into a four-neck round-bottom flask, and the mixture is uniformly stirred to uniformly suspend the powder; adding 10 parts of 5% NaOH solution and 6 parts of N, N-dimethyl-1, 3-propanediamine into another three-neck flask, and uniformly stirring for dissolving; heating the four-neck flask to 75 ℃ in a water bath, and slowly adding the liquid in the three-neck flask; after the feeding is finished, keeping the temperature and reacting for 4 hours; cooling to 25 ℃, adding 15 parts of NaOH solution with the concentration of 20 percent into the solution after reaction, stirring for 1h for hydrolysis, naturally cooling the obtained hydrolysate system to normal temperature, adding hydrochloric acid for neutralization to neutrality, slowly dripping into absolute ethyl alcohol, and stirring to obtain a solid product, namely the modified polyaspartic acid, wherein the solid product is obtained after washing and drying the precipitate by using acetone.
The density of the water-based drilling fluid system is 1.05g/cm 3 The hot rolling temperature of the drilling fluid system is 130 ℃.
Example 2
A water-based drilling fluid for ultra-large displacement wells comprises water, an alkaline pH regulator, a filtrate reducer, a coating agent, a weighting agent, a flow pattern regulator, a polyamine inhibitor and a multifunctional lubricating drag reducer;
the weight percentage of each component in water is as follows:
water: 100;
alkaline pH adjuster: 0.5 percent;
fluid loss additive: 1.2 percent;
coating agent: 0.6 percent;
weighting agent: 7.5 percent;
flow pattern regulator: 0.5 percent;
polyamine inhibitors: 1.2 percent;
multifunctional lubricating drag reducer: 15 percent;
the water is seawater;
wherein the alkaline pH regulator comprises 40 parts of sodium hydroxide, 40 parts of sodium carbonate and 20 parts of magnesium hydroxide by 100 parts by weight;
the fluid loss additive comprises 45 parts of carboxymethyl starch (CMS) and 55 parts of polyanionic cellulose (PAC) by 100 parts by weight;
the coating agent is partially hydrolyzed polyacrylamide;
the weighting agent is commercially available barite of 500 meshes;
the flow pattern regulator comprises 60 parts of xanthan gum and 40 parts of guar gum by 100 parts by weight;
the polyamine inhibitor is an amino polymer obtained by polymerizing diethylene glycol bis (3-aminopropyl) ether and maleic anhydride; the preparation steps of the polyamine inhibitor are as follows:
firstly, adding 50 parts of diethylene glycol bis (3-aminopropyl) ether into a four-neck round-bottom flask, placing the four-neck round-bottom flask into a constant-temperature oil bath, starting stirring, and introducing nitrogen to remove oxygen; after the temperature is raised to 60 ℃, 25 parts of maleic anhydride is slowly added, and the temperature in the flask is controlled not to exceed 65 ℃ by controlling the adding speed; after the feeding is finished, introducing nitrogen again, sealing the flask opening, and keeping the temperature for 30min; after slowly raising the temperature to 140 ℃, maintaining the reaction temperature of 140 ℃ and keeping the temperature for 3h. Then naturally cooling to normal temperature to obtain the polyamine inhibitor.
The multifunctional lubricating drag reducer comprises, by weight, 200 parts of water, 70 parts of modified polyaspartic acid and 30 parts of polyol phosphate;
the preparation steps of the modified polyaspartic acid are as follows:
firstly, 100 parts of deionized water and 20 parts of polysuccinimide powder are added into a four-neck round-bottom flask, and the mixture is uniformly stirred to uniformly suspend the powder; adding 12 parts of 5% NaOH solution and 8 parts of N, N-dimethyl-1, 3-propanediamine into another three-neck flask, and uniformly stirring to dissolve; heating the four-neck flask in water bath to 80 ℃, and slowly adding the liquid in the three-neck flask; after the feeding is finished, keeping the temperature and reacting for 3 hours; cooling to 35 ℃, adding 16 parts of NaOH solution with the concentration of 20 percent into the solution after the reaction, stirring for 0.5h for hydrolysis, naturally cooling the obtained hydrolysate system to normal temperature, adding hydrochloric acid for neutralization to neutrality, slowly dripping into absolute ethyl alcohol, and stirring to obtain a solid product, namely the modified polyaspartic acid, wherein the solid product is obtained after the precipitate is washed and dried by acetone.
The density of the water-based drilling fluid system is 1.10g/cm 3 The hot rolling temperature of the drilling fluid system is 130 DEG C
Example 3
A water-based drilling fluid for ultra-large displacement wells comprises water, an alkaline pH regulator, a fluid loss additive, a coating agent, a weighting agent, a flow pattern regulator, a polyamine inhibitor and a multifunctional lubricating drag reducer;
the weight percentage of each component in water is as follows:
water: 100, respectively;
alkaline pH adjuster: 0.6 percent;
fluid loss additive: 1.4 percent;
coating agent: 0.8 percent;
weighting agent: 36 percent;
flow pattern regulator: 0.5 percent;
polyamine inhibitors: 1.4 percent;
multifunctional lubricating drag reducer: 15 percent;
the water is seawater;
the specific species of each component were the same as in example 2;
the density of the water-based drilling fluid system is 1.30g/cm 3 The hot rolling temperature of the drilling fluid system is 130 ℃.
Example 4
A water-based drilling fluid for ultra-large displacement wells comprises water, an alkaline pH regulator, a filtrate reducer, a coating agent, a weighting agent, a flow pattern regulator, a polyamine inhibitor and a multifunctional lubricating drag reducer;
the weight percentage of each component in water is as follows:
water: 100;
alkaline pH adjuster: 0.6 percent;
fluid loss additive: 1.4 percent;
coating agent: 0.8 percent;
weighting agent: 36 percent;
flow pattern regulator: 0.5 percent;
polyamine inhibitors: 1.4 percent;
multifunctional lubricating drag reducer: 10 percent;
the water is seawater;
the specific species of each component were the same as in example 2;
the density of the water-based drilling fluid system is 1.30g/cm 3 Drilling fluidThe hot rolling temperature of the system is 130 ℃.
Example 5
A water-based drilling fluid for ultra-large displacement wells comprises water, an alkaline pH regulator, a filtrate reducer, a coating agent, a weighting agent, a flow pattern regulator, a polyamine inhibitor and a multifunctional lubricating drag reducer;
the weight percentage of each component in water is as follows:
water: 100, respectively;
alkaline pH adjuster: 0.6 percent;
fluid loss additive: 1.4 percent;
coating agent: 0.8 percent;
weighting agent: 36 percent;
flow pattern regulator: 0.5 percent;
polyamine inhibitors: 1.4 percent;
multifunctional lubricating drag reducer: 20 percent;
the water is seawater;
the specific species of each component were the same as in example 2;
the density of the water-based drilling fluid system is 1.30g/cm 3 The hot rolling temperature of the drilling fluid system is 130 ℃.
Example 6
A water-based drilling fluid for ultra-large displacement wells comprises water, an alkaline pH regulator, a filtrate reducer, a coating agent, a weighting agent, a flow pattern regulator, a polyamine inhibitor and a multifunctional lubricating drag reducer;
the weight percentage of each component in water is as follows:
water: 100, respectively;
alkaline pH adjuster: 0.6 percent;
fluid loss additive: 1.4 percent;
coating agent: 0.8 percent;
weighting agent: 75 percent;
flow pattern regulator: 0.5 percent;
polyamine inhibitors: 1.4 percent;
multifunctional lubricating drag reducer: 15 percent;
the water is seawater;
wherein the alkaline pH regulator comprises 40 parts of sodium hydroxide, 40 parts of sodium carbonate and 20 parts of magnesium hydroxide by 100 parts by weight;
the fluid loss additive comprises 40 parts of carboxymethyl starch (CMS) and 60 parts of polyanionic cellulose (PAC) by 100 parts by weight;
the coating agent is partially hydrolyzed polyacrylamide;
the weighting agent is commercially available barite with 500 meshes;
the flow pattern regulator comprises 60 parts of xanthan gum and 40 parts of guar gum by 100 parts by weight;
the polyamine inhibitor used in this example was prepared in the same manner as in example 2;
the multifunctional lubricating drag reducer is compounded by modified polyaspartic acid and polyol phosphate;
the multifunctional lubricating drag reducer comprises, by weight, 200 parts of water, 70 parts of modified polyaspartic acid and 30 parts of polyol phosphate;
the modified polyaspartic acid used in this example was prepared in the same manner as in example 2.
The density of the drilling fluid system is 1.50g/cm 3 The hot rolling temperature of the drilling fluid system is 130 ℃.
Example 7
A water-based drilling fluid for ultra-large displacement wells comprises water, an alkaline pH regulator, a fluid loss additive, a coating agent, a weighting agent, a flow pattern regulator, a polyamine inhibitor and a multifunctional lubricating drag reducer;
the weight percentage of each component in water is as follows:
water: 100;
alkaline pH adjuster: 0.5 percent;
fluid loss additive: 1.2 percent;
coating agent: 0.8 percent;
weighting agent: 36 percent;
flow pattern regulator: 0.5 percent;
polyamine inhibitors: 1.2 percent;
multifunctional lubricating drag reducer: 15 percent;
the water is seawater;
wherein the alkaline pH regulator comprises 40 parts of sodium hydroxide, 40 parts of sodium carbonate and 20 parts of magnesium hydroxide by 100 parts by weight;
the fluid loss additive comprises 45 parts of carboxymethyl starch (CMS) and 55 parts of polyanionic cellulose (PAC) by 100 parts by weight;
the coating agent is partially hydrolyzed polyacrylamide;
the weighting agent is commercially available barite of 500 meshes;
the flow pattern regulator comprises 60 parts of xanthan gum and 40 parts of guar gum by 100 parts by weight;
the polyamine inhibitor used in this example was prepared in the same manner as in example 2.
The multifunctional lubricating drag reducer comprises, by weight, 200 parts, preferably 100 parts of water, 70 parts of modified polyaspartic acid and 30 parts of polyol phosphate;
the modified polyaspartic acid used in this example was prepared in the same manner as in example 2.
The density of the drilling fluid system is 1.30g/cm 3 The hot rolling temperature of the drilling fluid system is 110 ℃.
Example 8
A water-based drilling fluid for ultra-large displacement wells comprises water, an alkaline pH regulator, a fluid loss additive, a coating agent, a weighting agent, a flow pattern regulator, a polyamine inhibitor and a multifunctional lubricating drag reducer;
the weight percentage of each component in water is as follows:
water: 100, respectively;
alkaline pH adjuster: 0.8 percent;
fluid loss additive: 1.6 percent;
coating agent: 1.0 percent;
weighting agent: 36 percent;
flow pattern regulator: 0.6 percent;
polyamine inhibitors: 1.5 percent;
multifunctional lubricating drag reducer: 15 percent;
the water is seawater;
wherein the alkaline pH regulator comprises 30 parts of sodium hydroxide, 30 parts of sodium carbonate and 40 parts of magnesium hydroxide by 100 parts by weight;
the fluid loss additive comprises 30 parts of carboxymethyl starch (CMS) and 70 parts of polyanionic cellulose (PAC) by 100 parts by weight.
The coating agent is partially hydrolyzed polyacrylamide;
the weighting agent is commercially available barite of 500 meshes;
the flow pattern regulator comprises 80 parts of xanthan gum and 20 parts of guar gum by 100 parts by weight;
the polyamine inhibitor used in this example was prepared in the same manner as in example 2;
the multifunctional lubricating drag reducer comprises, by weight, 200 parts of water, 70 parts of modified polyaspartic acid and 30 parts of polyol phosphate;
the preparation method of modified polyaspartic acid used in this example was the same as that of example 2;
the density of the drilling fluid system is 1.3g/cm 3 The hot rolling temperature of the drilling fluid system is 150 ℃.
Comparative example 1
The water-base drilling fluid for ultra-large displacement well consists of water, alkaline pH regulator, filtrate reducer, coating agent, weighting agent, flow pattern regulator and multifunctional lubricating drag reducer;
the weight percentage of each component in water is as follows:
water: 100, respectively;
alkaline pH adjuster: 0.6 percent;
fluid loss additive: 1.4 percent;
coating agent: 0.8 percent;
weighting agent: 36 percent;
flow pattern regulator: 0.5 percent;
polyamine inhibitors: 0
Multifunctional lubricating drag reducer: 15 percent;
the water is seawater;
the kinds of the components are the same as those in example 2;
the density of the drilling fluid system is 1.30g/cm 3 The hot rolling temperature of the drilling fluid system is 130 ℃.
Comparative example 2
A water-based drilling fluid for ultra-large displacement wells comprises water, an alkaline pH regulator, a filtrate reducer, a coating agent, a weighting agent, a flow pattern regulator and a polyamine inhibitor;
the weight percentage of each component in water is as follows:
water: 100, respectively;
alkaline pH adjuster: 0.6 percent;
fluid loss additive: 1.4 percent;
coating agent: 0.8 percent;
weighting agent: 36 percent;
flow pattern regulator: 0.5 percent;
polyamine inhibitors: 1.4 percent;
multifunctional lubricating drag reducer: 0
The water is seawater;
the specific species of each component were the same as in example 2.
The density of the drilling fluid system is 1.30g/cm 3 The hot rolling temperature of the drilling fluid system is 130 ℃.
Comparative example 3
Oil-based drilling fluids: fully mixing 75 parts of 3# white oil, 25 parts of 25% calcium chloride aqueous solution, 4.0 parts of JHEMUL (main emulsifier), 1.0 part of JHCOAT (auxiliary emulsifier), 1.0 part of cutting agent JHERO, 2.0 parts of CaO as alkalinity regulator, 2.0 parts of organic soil JHMOGEL, 3.0 parts of fluid loss additive JHFO, 3.0 parts of blocking agent JHSEAL and 48 parts of barite to obtain the oil-based drilling fluid. The density of the drilling fluid system is 1.3g/cm 3 The hot rolling temperature of the drilling fluid system is 130 DEG C
According to GB/T16783.1-2012' field test of drilling fluid in petroleum and natural gas industry part 1: water-based drilling fluids and GB/T16783.2-2012 "oil and gas industry drilling fluids field test part 2: oil-based drilling fluids "rheological properties, fluid loss properties, etc. of examples 1 to 8 and comparative examples 1 to 3 were evaluated, and the experimental results are shown in table 1.
According to Q/SYTZ 0022-2015 technical requirements and experimental methods of the liquid lubricant for drilling fluid, a FANN extreme pressure lubricator is used indoors to test the friction resistance coefficients of the examples 1-8 and the comparative examples 1-3 under the action of 150 inches per pound, and the experimental results are shown in Table 1;
according to GB/T3142-2019 four-ball method for measuring the bearing capacity of a lubricant, a micro-control full-automatic four-ball friction tester of SGW-10W of Jinan Hengxu tester technology Limited company is used indoors to evaluate the diameter of the grinding crack of the steel ball in the examples 1-8 and the diameters of the grinding crack of the steel ball in the comparative examples 1-3 under the condition of 147N load and 60min are shown in the figures 1-11, and the average friction coefficient is shown in the table 1. The diameters of the grinding marks in the figures 1-11 are 0.662mm, 0.714mm, 0.780mm, 0.793mm, 0.606mm, 0.744mm, 0.751mm, 0.753mm, 0.827mm, 1.441mm and 0.738mm in sequence; the smaller the diameter of the grinding trace of the steel ball is, the better the wear resistance of the drilling fluid system is; the smaller the average friction coefficient, the better the lubricity of the drilling fluid system.
The rolling recovery rates of the shale of examples 1 to 8 and comparative examples 1 to 3 were measured according to SY/T5613-2016 (test method for physical and chemical properties of shale in drilling fluid test), and the results are shown in Table 1.
TABLE 1 drilling fluid base Properties of the examples and comparative examples
Figure BDA0003842062820000171
Figure BDA0003842062820000181
Examples 1, 2, 3 and 6 compare the drilling fluid performance at the same temperature and different densities, and it can be seen from examples 1, 2, 3 and 6 that the ultra-large displacement water-based drilling fluid system is 1.50g/cm 3 The rheological property, the fluid loss property, the lubricating property, the inhibition property and other parameters are better and are kept stable; examples 3, 7 and 8 compare the performances of the drilling fluid at the same density and different temperatures, and it can be known from examples 3, 7 and 8 that the ultra-large displacement water-based drilling fluid system has better rheological property, fluid loss property, lubricating property, inhibition property and other parameters below 150 ℃ and keeps stable; as can be seen from example 3 and comparative examples 1 and 2, the addition polymerization inhibitor was not added to the system, the viscosity and shear strength were significantly increased, the fluid loss at high temperature and high pressure was also increased, and the rollingThe recovery rate is reduced, a multifunctional lubricant is not added in the system, the rheological property and the inhibition property are both reduced, and the lubricating drag reduction property is obviously reduced, which shows that the multifunctional lubricating drag reducer has good lubricating drag reduction property and a certain inhibition effect; as can be seen from example 3 and comparative example 3, the extreme pressure lubrication coefficient, the average friction coefficient and the steel ball wear scar diameter of the system are equivalent to those of the oil-based system, which shows that the lubricating and antiwear performance of the ultra-large displacement water-based drilling fluid system is comparable to that of the oil-based system.
In summary, eight groups of embodiments of the ultra-extended reach well water-based drilling fluid of the present invention, after aging at different densities and different temperatures: the rheological property is good, the dynamic-plastic ratio and the readings of 6 turns and 3 turns are large, rock cleaning and sand carrying of the ultra-large displacement well are facilitated, and a rock debris bed is prevented from being generated in a horizontal section; the method has the characteristics of low API (American Petroleum institute) filtration loss and low high-temperature and high-pressure water loss, and is high in rolling recovery rate and strong in inhibition, so that the stability of the well wall in the operation process is kept; the extreme pressure lubrication coefficient and the average friction coefficient are equivalent to those of oil base, and the wear resistance is superior to that of oil base drilling fluid, which shows that the ultra-large displacement water-based drilling fluid has good performance of reducing friction torque, and can reduce the phenomena of holding torque, drilling sticking and the like.
Note:
t: the aging temperature of the drilling fluid at DEG C;
ρ: density of drilling fluid in g/cm 3 ；
AV: the apparent viscosity of the drilling fluid, mPa · s;
PV: the plastic viscosity of the drilling fluid, mPa & s;
YP: drilling fluid cutting force Pa;
phi 6: 6-turn reading of the six-speed rotary viscometer is dimensionless;
phi 3: 3-turn reading of the six-speed rotary viscometer is dimensionless;
API: medium pressure water loss (0.7MPa, T, 30min) of the drilling fluid, mL;
HTHP: the drilling fluid loses water (3.5MPa, T, 30min) at high temperature and high pressure, and is mL;
EP: extreme pressure lubrication coefficient, dimensionless;
AVG: average friction coefficient, dimensionless;
GD: rolling recovery,%.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and amendments can be made without departing from the principle of the present invention, and these modifications and amendments should also be considered as the protection scope of the present invention.

Claims (10)

1. The water-based drilling fluid is characterized by comprising a water-based fluid and the following components in percentage by mass:
alkaline pH adjuster: 0.2 to 1 percent;
fluid loss additive: 1 to 2 percent;
coating agent: 0.5 to 1 percent;
weighting agent: 0 to 100 percent;
flow pattern regulator: 0.2 to 1 percent;
polyamine inhibitors: 1 to 2 percent;
multifunctional lubricating drag reducer: 10 to 20 percent;
the polyamine inhibitor is an amino polymer obtained by polymerizing diethylene glycol bis (3-aminopropyl) ether and maleic anhydride;
the multifunctional lubricating drag reducer comprises, by mass, 200 parts of modified polyaspartic acid 60-70 parts, polyol phosphate 30-40 parts and water 100 parts;
the preparation of the modified polyaspartic acid comprises the following steps: mixing water, polysuccinimide powder, a first sodium hydroxide solution and N, N-dimethyl-1, 3-propane diamine, carrying out ring-opening polymerization at 70-80 ℃, cooling to 25-35 ℃, adding a second sodium hydroxide solution into the obtained product system, and hydrolyzing to obtain the modified polyaspartic acid.
2. The water-based drilling fluid of claim 1, wherein the water-based fluid is fresh water or seawater.
3. The water-based drilling fluid of claim 1, wherein the alkaline pH adjusting agent is one or more of sodium hydroxide, sodium carbonate, potassium hydroxide, and magnesium hydroxide.
4. The water-based drilling fluid according to claim 3, wherein the alkaline pH regulator comprises 30-40 parts of sodium hydroxide, 30-40 parts of sodium carbonate and 20-40 parts of magnesium hydroxide by mass based on 100 parts of the alkaline pH regulator.
5. The water-based drilling fluid of claim 1, wherein the fluid loss additive is one or more of carboxymethyl starch, hydroxyethyl starch, sodium carboxymethyl cellulose, and polyanionic cellulose.
6. The water-based drilling fluid of claim 1, wherein the coating agent is one or both of a zwitterionic polymer-based coating agent and a partially hydrolyzed polyacrylamide.
7. The water-based drilling fluid of claim 1, wherein the flow pattern modifier is one or more of xanthan gum, guar gum, konjac flour, sesbania flour, and artemisia gum.
8. The water-based drilling fluid according to claim 1, wherein the molar ratio of diethylene glycol bis (3-aminopropyl) ether to maleic anhydride is (1-10): (1-10).
9. The water-based drilling fluid of claim 1, wherein the weighting agent is barite.
10. The water-based drilling fluid according to claim 1, wherein the time for the ring-opening polymerization is 3 to 5 hours.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101921481A (en) * 2010-07-27 2010-12-22 北京化工大学 Gel prepared by in situ crosslinking hyaluronic acid and polyaspartic acid and preparation method thereof
CN106543436A (en) * 2016-11-01 2017-03-29 石家庄铁道大学 High molecular organic amine and maleic anhydride modified polyaspartic acid salts and its preparation method
CN113429948A (en) * 2021-08-09 2021-09-24 长江大学 Low-friction water-based drilling fluid and preparation method thereof
CN114058341A (en) * 2020-07-29 2022-02-18 中国石油化工股份有限公司 Additive for drilling fluid and composition for drilling fluid

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101921481A (en) * 2010-07-27 2010-12-22 北京化工大学 Gel prepared by in situ crosslinking hyaluronic acid and polyaspartic acid and preparation method thereof
CN106543436A (en) * 2016-11-01 2017-03-29 石家庄铁道大学 High molecular organic amine and maleic anhydride modified polyaspartic acid salts and its preparation method
CN114058341A (en) * 2020-07-29 2022-02-18 中国石油化工股份有限公司 Additive for drilling fluid and composition for drilling fluid
CN113429948A (en) * 2021-08-09 2021-09-24 长江大学 Low-friction water-based drilling fluid and preparation method thereof

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