A cationic bitumen composition for drilling fluids and a method for its preparation

Abstract

The application discloses a kind of drilling fluid cation asphalt compositions and preparation method thereof.The drilling fluid cation asphalt compositions of the application includes the following raw material components by weight parts: pre-modified asphalt: 100 parts; acid anhydride modifier: 2-10 parts; initiator: 0.08-0.7 parts; cation modifier: 6-15 parts; acid binding agent: 2-6 parts; quaternary amine agent: 0.5-5 parts; wherein, the pre-modified asphalt is inferior residue reduction modified by composite SBS modifier.The application uses difficult-to-handle inferior residue reduction as raw material, and after modification treatment, a modified asphalt with high softening point, good hydrophilicity and cation characteristics is obtained, which can be used as drilling fluid cation asphalt composition for oilfield drilling.

Description

Technical Field

[0001] This invention relates to an asphalt material and its preparation method, specifically to a cationic asphalt composition for drilling fluid and its preparation method. Background Technology

[0002] With the continuous expansion of the drilling field, the application of asphalt-based plugging agents in oilfield drilling is receiving increasing attention. Asphalt-based plugging agents generally contain water-insoluble asphalt particles and have a certain softening point. When the temperature and pressure inside the wellbore are sufficiently high, the asphalt particles soften and deform, and are squeezed into the micro-fractures in the wellbore, preventing drilling fluid from seeping through the micro-fractures and effectively sealing the formation together with the mud cake. Asphalt-based substances are extremely effective anti-collapse agents and reservoir protectants in oil drilling. For drilling operations in deep oil and gas fields, asphalt with a generally low softening point may become too soft or flowable, failing to meet the high-temperature requirements of deep well operations. High softening point asphalt (softening point above 100℃, especially above 120℃) can meet the requirements of deep drilling due to its excellent high-temperature resistance.

[0003] Asphalt, as an important additive in drilling fluids, has been used in oilfield drilling operations for many years, mainly for sealing, preventing collapse, and reducing filtration loss. Asphalt-based drilling fluid systems are primarily oil-based, but oil-based drilling fluids have certain drawbacks in terms of cost and environmental impact. Water-based drilling fluids are receiving increasing attention, and in recent years, water-based drilling fluids with cationic properties have gradually become popular in oilfields. However, preparing asphalt materials with certain cationic properties for use in water-based drilling fluids presents significant challenges.

[0004] As crude oil becomes increasingly heavy, the yield of vacuum residue gradually increases, leading to higher levels of heavy metals and sulfur in the residue. The relative contents of saturated fractions and asphaltenes also rise, while the relative contents of aromatics and gums decrease. Furthermore, the asphaltenes exhibit greater association and more complex forms, making it more difficult to directly convert inferior residue into high-grade asphalt. Therefore, for this increasingly deteriorating residue, if it can be modified into asphalt particles with high softening points, good hydrophilicity, and cationic properties, it could provide the conditions for preparing asphalt-based water-based cationic drilling fluids.

[0005] CN104559247B discloses a method for preparing high softening point asphalt particles. This method combines two types of high softening point asphalt with different softening points for granulation. During the granulation process, low-temperature embrittlement is carried out and inorganic micro powder and surfactant are introduced. The resulting high softening point asphalt particles can function under drilling conditions in a wide temperature range. However, the asphalt particles have poor hydrophilicity and can only be used in oil-based drilling fluid systems. Furthermore, the particle surface does not exhibit cationic characteristics, so the sealing, anti-collapse, and filtration loss reduction effects are generally limited in oil wells where anions are predominant.

[0006] CN103805221B discloses a method for producing high softening point asphalt. The raw material for this method is a mixture of coal tar pitch and petroleum asphalt. The method utilizes the characteristics of low viscosity and high reactivity of coal tar pitch at high temperatures to promote the oxidation reaction. However, the oxidation process of coal tar pitch releases a large amount of toxic and harmful gases, which are harmful to the environment and human health. Furthermore, the high softening point asphalt prepared does not have hydrophilic properties and cannot be used as a raw material for preparing asphalt-based water-based drilling fluids.

[0007] CN1415699A discloses a method for producing oxidized asphalt. First, a static mixer is used to mix air and asphalt, dispersing the air as tiny bubbles into the asphalt raw material. Then, the mixture enters an oxidation unit for an oxidation reaction. This method can adjust the properties of asphalt when producing ordinary road asphalt and building asphalt, but it is not suitable for producing asphalt with a high softening point. This is because the amount of air present in asphalt at high temperatures is very small, resulting in limited oxidation efficiency and failing to significantly increase the softening point of the asphalt. Furthermore, coking occurs during the production process.

[0008] In summary, the above methods have problems such as high energy consumption, complex processes, and environmental pollution when preparing high softening point asphalt. In addition, the ability to improve the softening point of asphalt during the preparation process is limited, and the high softening point asphalt produced has poor hydrophilicity and does not exhibit cationic properties, so it is not suitable for preparing cationic asphalt compositions for drilling fluids. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a cationic bitumen composition for drilling fluids and its preparation method. This invention uses difficult-to-process, low-quality slag as raw material, and through modification treatment, obtains modified bitumen with a high softening point, good hydrophilicity, and exhibiting cationic properties, which can be used as a cationic bitumen composition for oilfield drilling.

[0010] The first aspect of this invention provides a cationic bitumen composition for drilling fluid, comprising the following raw material components by weight:

[0011] Pre-modified asphalt: 100 parts;

[0012] Anhydride modifier: 2-10 parts;

[0013] Initiator: 0.08–0.7 parts;

[0014] Cationic modifier: 6-15 parts;

[0015] Acid-binding agent: 2-6 parts;

[0016] Quaternizing agent: 0.5–5 parts;

[0017] The pre-modified asphalt is obtained by modifying inferior slag with a composite SBS modifier.

[0018] The pre-modified asphalt, by weight, comprises the following raw material components:

[0019] Inferior slag reduction: 100 portions;

[0020] Compatibilizer: 3-6 parts;

[0021] Composite SBS modifier: 5-7 parts;

[0022] Stabilizer: 0.1 to 0.5 parts.

[0023] The cationic bitumen composition for drilling fluid comprises, by weight, the following raw material components:

[0024] Pre-modified asphalt: 100 parts;

[0025] Anhydride modifier: 2-8 parts;

[0026] Initiator: 0.15–0.7 parts;

[0027] Cationic modifier: 8-15 parts;

[0028] Acid-binding agent: 2-5 parts;

[0029] Quaternary ammonifying agent: 0.5 to 3 parts.

[0030] The pre-modified asphalt, by weight, comprises the following raw material components:

[0031] Inferior slag reduction: 100 portions;

[0032] Compatibilizer: 3.5–5 parts;

[0033] Composite SBS modifier: 5-6.2 parts;

[0034] Stabilizer: 0.15 to 0.4 parts.

[0035] The properties of the inferior slag include: a flash point of 241℃~256℃, a sulfur content of 2.61wt%~3.65wt%, and by mass fraction, saturated components of 26.1%~37.7%, aromatic components of 20.2%~34.5%, resins of 18.3%~24.8%, asphaltene of 21.3%~30.1%, with preferred asphaltene content of 21.3%~26.0%.

[0036] The inferior slag also has the following properties: residual carbon value of 21wt% to 29wt%, nitrogen content of 0.14wt% to 0.61wt%, total nickel and vanadium content of 320 to 365μg / g, and condensation index CI of 0.26 to 0.35.

[0037] The inferior reduced slag can be Tarim River reduced slag and / or other reduced slag that meet the above properties, and the inferior reduced slag is a fraction with an initial boiling point greater than 425°C.

[0038] The compatibilizer is an adhesive obtained through conventional solvent deasphalting processes in the art.

[0039] The compatibilizer has the following properties: kinematic viscosity of 50 mmHg at 100°C. 2 / s~65mm 2 / s, flash point is 206℃~220℃, by mass fraction, saturated fraction accounts for 30%~42%, aromatic fraction accounts for 48%~57%, resin accounts for 8%~13%, asphaltene content is less than 2%; weight average molecular weight is 1990~2140, molecular weight distribution width is 1.6~3.7.

[0040] The composite SBS modifier includes linear SBS modifiers and star-shaped SBS modifiers. The linear SBS modifier accounts for 45%–70% of the total mass of the composite SBS modifier; the star-shaped SBS modifier accounts for 30%–55% of the total mass of the composite SBS modifier.

[0041] The linear SBS modifier has the following properties: a styrene to butadiene mass ratio of 12–20:80–88, and a tensile strength of 280–350 kg / cm². 2 It has an elongation at break of 800%–910% and a Shore hardness of 75±6HA.

[0042] The star-shaped SBS modifier has the following properties: the mass ratio of styrene to butadiene is 35-45:55-65, and the tensile strength is 200-300 kg / cm². 2 Its elongation at break is 720%–800%, and its Shore hardness is 90±5HA.

[0043] The stabilizer is elemental sulfur and one or more of the following: tetramethylthiuram disulfide, disodium thiodipropionate, disodium octadecyl thiodipropionate, di(tridecyl) thiodipropionate, distearate thiodipropionate, zinc hydroxystannate, hydroquinone, zinc dimethyl thiocarbamate, zinc stearate, and thiocarbamate. Preferably, the elemental sulfur accounts for 70% to 90% of the total stabilizer by weight.

[0044] The anhydride modifier is one or more of maleic anhydride, polyisobutylene succinic anhydride, methyl nadic anhydride, modified methyl nadic anhydride MNA-10, dodecenyl succinic anhydride, tung oil anhydride, polyazelite anhydride, polyglutaric anhydride, polyoxoanhydride, or hydrolyzed polymaleic anhydride.

[0045] The initiator is one or more of dicumyl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, sodium metabisulfite, azobisisobutyronitrile, azobisisoheptanenitrile, and cumyl hydroperoxide.

[0046] The cationic modifier is polyethyleneimine, which has one or more molecular weights from 1,000 to 70,000, preferably one or more molecular weights from 1,000, 20,000, and 70,000.

[0047] The acid-binding agent is triethylamine (Et3N) and / or 4-dimethylaminopyridine (DMAP).

[0048] The quaternizing agent is one or more of hexadecyl bromide (BHD), iodomethane (IMT), and benzyl chloride (BC).

[0049] A second aspect of the present invention provides a method for preparing the above-mentioned cationic bitumen composition for drilling fluids, comprising:

[0050] (1) Preparation of pre-modified asphalt;

[0051] (2) Add anhydride modifier and initiator to the pre-modified asphalt obtained in step (1), stir and heat to the reaction temperature, and carry out the reaction under protective gas;

[0052] (3) Dissolve the material obtained in step (2) in chloroform, add cationic modifier and acid binder, and react under the first heating reflux condition; after the reaction is completed, add quaternary ammonium agent and react under the second heating reflux condition to obtain a cationic bitumen composition for drilling fluid.

[0053] In step (1), the preparation process of the pre-modified asphalt is as follows:

[0054] Inferior slag is heated to a molten state, and compatibilizer and composite SBS modifier are added before shearing. After shearing, stabilizer is added, and the mixture is stirred and developed. After development, pre-modified asphalt is obtained.

[0055] The shearing rate is 3000–5000 r / min, preferably 3000–4500 r / min, the shearing time is 40–60 min, and the required temperature during shearing is 160℃–185℃, preferably 170℃–185℃. The development temperature is 180℃–195℃, and the development time is 4h–8h.

[0056] In step (2), the stirring speed is 600–800 r / min. The reaction temperature is 160°C–180°C, and the reaction time is 6–8 h. Heating to the reaction temperature is preferably done using programmed temperature rise, with a heating rate of 1°C–3°C / min. The protective gas is an inert gas and / or N2. The amount of protective gas is such that the reaction pressure is maintained at 0.3–0.9 MPa, preferably 0.5–0.9 MPa.

[0057] In step (3), the reaction temperature of the first reflux is 40℃~90℃, preferably 45℃~80℃, and the reaction time is 10~16h; the reaction temperature of the second reflux is 40℃~80℃, preferably 40℃~60℃, and the reaction time is 20~24h. Preferably, the reaction temperature of the second reflux is 10~20℃ lower than the reaction temperature of the first reflux.

[0058] In step (3), the reaction is carried out under the second heating reflux condition, and then cooled and rotary evaporated to obtain a cationic bitumen composition for drilling fluid. The rotary evaporation is to remove organic solvents.

[0059] The cationic bitumen composition for drilling fluid needs to be cryogenically pulverized before use.

[0060] The freezing temperature is -15℃ to -45℃, preferably -20℃ to -35℃, and the freezing time is 6 to 24 hours, preferably 12 to 24 hours.

[0061] The pulverization process is carried out in equipment such as high-speed shear pulverizer, colloid mill, and ball mill, and the pulverization time is 30-100s, preferably 30-60s.

[0062] Compared with the prior art, the present invention has the following advantages:

[0063] (1) The inferior slag used in this invention is a low-value-added raw material, which is not suitable for producing modified asphalt for drilling fluid. For example, Tahe slag has a high asphalt content, a very special form, and extremely poor comprehensive performance. However, through the synergistic cooperation of various raw materials in this invention, it can be comprehensively modified and used to prepare high softening point asphalt for drilling fluid, thus expanding the use of inferior raw materials and increasing their added value.

[0064] (2) The present invention adopts a three-stage modification method of polymer pre-modification, acid anhydride modification and cationic modification. The three modification methods work together and promote each other, which greatly improves the softening point, hydrophilicity and cationic properties of asphalt. While maintaining the original viscoelastic properties of asphalt, it increases its sealing ability in high temperature and water-based environments, making it more suitable for drilling fluid asphalt fields.

[0065] (3) The present invention selects special raw materials and preparation and modification methods. The resulting cationic asphalt composition for drilling fluid not only has a high softening point and good hydrophilicity, but also exhibits cationic characteristics in an aqueous environment. Moreover, the prepared product has less viscous components after solvent recovery and drying, and exhibits obvious hardness and brittleness. Further freezing and pulverization can yield modified asphalt particles with uniform particle size, reducing the difficulty of pulverization. Detailed Implementation

[0066] The technical solution of the present invention is further described below through embodiments, but these embodiments cannot limit the scope of protection of the present invention, and the wt% involved refers to the mass fraction.

[0067] In this invention, the softening point was tested according to the requirements of the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering JTG E20-2011", the contact angle was measured using the OCA25 video optical contact angle measuring instrument developed and manufactured by Dataphysics GmbH, Germany, the high temperature and high pressure filtration loss was determined according to the SY / T5621 method, and the cationization degree was determined by the sodium tetraphenylborate back titration method.

[0068] Example 1

[0069] (1) Add 4 parts of compatibilizer (resin obtained by solvent deasphalting process, kinematic viscosity of 60 mmHg at 100℃) to 100 parts of Tarim slag heated to a fluid state (properties shown in Table 1). 2 / s, flash point 212℃, by mass fraction, saturated fraction 33%, aromatic fraction 56.5%, resin 10%, asphaltene 0.5%; weight average molecular weight 2090, molecular weight distribution width 2.7), 3.3 parts linear SBS modifier and 2.2 parts star-shaped SBS modifier (linear SBS modifier accounts for 65wt% of the total, the linear SBS modifier has the following properties: styrene to butadiene mass ratio of 20:80, tensile strength 300kg / cm 2 The elongation at break is 820%, and the Shore hardness is 75HA. The star-shaped SBS modifier has the following properties: the mass ratio of styrene to butadiene is 40:60, and the tensile strength is 250 kg / cm². 2 The asphalt (with an elongation at break of 750% and a Shore hardness of 90 HA) was sheared at 180℃ and 4500 r / min for 50 min. After shearing, 0.1 parts of elemental sulfur and 0.05 parts of tetramethylthiuram disulfide were added, and the mixture was stirred and developed at 183℃ and 400 r / min for 6 h to obtain pre-modified asphalt.

[0070] (2) Take 100 parts of the pre-modified asphalt obtained in (1) and add 5 parts of maleic anhydride and 0.5 parts of dicumyl peroxide. Under the stirring speed of 650 r / min, the temperature is increased to 175℃ at a speed program of 2℃ / min. After the temperature is increased, the reaction is carried out under N2 atmosphere. The pressure in the reactor is maintained at 0.6 MPa and the reaction time is 6h.

[0071] (3) After cooling the material obtained in (2), dissolve it completely in chloroform, add 10 parts of polyethyleneimine with a molecular weight of 70,000 and 3 parts of triethylamine, and heat and reflux at 60°C for 12 hours to carry out the reaction. After the reaction is completed, add 1 part of benzyl chloride (BC) and heat and reflux at 50°C for 24 hours. After the reaction is completed, a cationic asphalt composition A1 for drilling fluid is obtained.

[0072] Example 2

[0073] (1) Add 4 parts of compatibilizer (resin obtained by solvent deasphalting process, kinematic viscosity of 60 mmHg at 100℃) to 100 parts of Tarim slag heated to a fluid state (properties shown in Table 1). 2 / s, flash point 212℃, by mass fraction, saturated fraction 33%, aromatic fraction 56.5%, resin 10%, asphaltene 0.5%; weight average molecular weight 2090, molecular weight distribution width 2.7), 3.3 parts linear SBS modifier and 2.2 parts star-shaped SBS modifier (linear SBS modifier accounts for 65wt% of the total, the linear SBS modifier has the following properties: styrene to butadiene mass ratio of 20:80, tensile strength 300kg / cm 2 The elongation at break is 820%, and the Shore hardness is 75HA. The star-shaped SBS modifier has the following properties: the mass ratio of styrene to butadiene is 40:60, and the tensile strength is 250 kg / cm². 2 The asphalt (with an elongation at break of 750% and a Shore hardness of 90 HA) was sheared at 180℃ and 4500 r / min for 50 min. After shearing, 0.1 parts of elemental sulfur and 0.05 parts of tetramethylthiuram disulfide were added, and the mixture was stirred and developed at 183℃ and 400 r / min for 6 h to obtain pre-modified asphalt.

[0074] (2) Take 100 parts of the pre-modified asphalt obtained in (1) and add 4 parts of maleic anhydride and 0.25 parts of dicumyl peroxide. Under the stirring speed of 650 r / min, the temperature is increased to 175℃ at a speed program of 2℃ / min. After the temperature is increased, the reaction is carried out under N2 atmosphere. The pressure in the reactor is maintained at 0.6 MPa and the reaction time is 6h.

[0075] (3) After cooling the material obtained in (2), dissolve it completely in chloroform, add 10 parts of polyethyleneimine with a molecular weight of 20,000 and 3 parts of triethylamine, and heat and reflux at 60°C for 12 hours to carry out the reaction. After the reaction is completed, add 1 part of benzyl chloride (BC) and heat and reflux at 50°C for 24 hours. After the reaction is completed, a cationic asphalt composition A2 for drilling fluid is obtained.

[0076] Example 3

[0077] (1) Add 4 parts of compatibilizer (resin obtained by solvent deasphalting process, kinematic viscosity of 60 mmHg at 100℃) to 100 parts of Tarim slag heated to a fluid state (properties shown in Table 1). 2 / s, flash point 212℃, by mass fraction, saturated fraction 33%, aromatic fraction 56.5%, resin 10%, asphaltene 0.5%; weight average molecular weight 2090, molecular weight distribution width 2.7), 3.5 parts linear SBS modifier and 2.5 parts star-shaped SBS modifier (linear SBS modifier accounts for 65wt% of the total, the linear SBS modifier has the following properties: styrene to butadiene mass ratio of 20:80, tensile strength 300kg / cm 2 The elongation at break is 820%, and the Shore hardness is 75HA. The star-shaped SBS modifier has the following properties: the mass ratio of styrene to butadiene is 40:60, and the tensile strength is 250 kg / cm². 2 The asphalt (with an elongation at break of 750% and a Shore hardness of 90HA) was sheared at 180℃ and 4500r / min for 50min. After shearing, 0.15 parts of elemental sulfur and 0.07 parts of tetramethylthiuram disulfide were added, and the mixture was stirred and developed at 183℃ and 400r / min for 6h to obtain pre-modified asphalt.

[0078] (2) Take 100 parts of the pre-modified asphalt obtained in (1) and add 5 parts of maleic anhydride and 0.5 parts of dicumyl peroxide. Under the stirring speed of 650 r / min, the temperature is increased to 175℃ at a speed program of 2℃ / min. After the temperature is increased, the reaction is carried out under N2 atmosphere. The pressure in the reactor is maintained at 0.6 MPa and the reaction time is 6h.

[0079] (3) After cooling the material in (2), dissolve it completely in chloroform, add 10 parts of PEI with a molecular weight of 70,000 and 3 parts of triethylamine, and heat and reflux at 60°C for 12 hours to carry out the reaction. After the reaction is completed, add 1 part of benzyl chloride (BC) and heat and reflux at 50°C for 24 hours. After the reaction is completed, the cationic bitumen composition A3 for drilling fluid is obtained.

[0080] Example 4

[0081] (1) Add 4.5 parts of compatibilizer (the resin obtained by solvent deasphalting process, with a kinematic viscosity of 60 mmHg at 100°C) to 100 parts of Tarim slag heated to a fluid state (properties shown in Table 1). 2 / s, flash point 212℃, by mass fraction, saturated fraction 33%, aromatic fraction 56.5%, resin 10%, asphaltene 0.5%; weight average molecular weight 2090, molecular weight distribution width 2.7), 3.3 parts linear SBS modifier and 2.2 parts star-shaped SBS modifier (linear SBS modifier accounts for 65wt% of the total, the linear SBS modifier has the following properties: styrene to butadiene mass ratio of 20:80, tensile strength 300kg / cm 2 The elongation at break is 820%, and the Shore hardness is 75HA. The star-shaped SBS modifier has the following properties: the mass ratio of styrene to butadiene is 40:60, and the tensile strength is 250 kg / cm². 2 The asphalt (with an elongation at break of 750% and a Shore hardness of 90HA) was sheared at 180℃ and 4500r / min for 50min. After shearing, 0.2 parts of elemental sulfur and 0.05 parts of didodecyl thiodipropionate were added, and the mixture was stirred and developed at 183℃ and 400r / min for 6h to obtain pre-modified asphalt.

[0082] (2) Take 100 parts of the pre-modified asphalt obtained in (1) and add 5 parts of maleic anhydride, 2 parts of methyl nadic anhydride and 0.45 parts of azobisisobutyronitrile. Under a stirring speed of 650 r / min, the temperature is increased to 175℃ at a speed program of 2℃ / min. After the temperature is increased, the reaction is carried out under N2 atmosphere. The pressure in the reactor is maintained at 0.6 MPa and the reaction time is 6 h.

[0083] (3) After cooling the material obtained in (2), dissolve it completely in chloroform, add 10 parts of polyethyleneimine with a molecular weight of 70,000, 2 parts of PEI with a molecular weight of 20,000 and 3 parts of triethylamine, and heat and reflux at 60°C for 12 hours to carry out the reaction. After the reaction is completed, add 1 part of benzyl chloride (BC) and 0.5 parts of iodomethane (IMT), and heat and reflux at 50°C for 24 hours. After the reaction is completed, a cationic bitumen composition A4 for drilling fluid is obtained.

[0084] Example 5

[0085] (1) Add 4.5 parts of compatibilizer (the resin obtained by solvent deasphalting process, with a kinematic viscosity of 60 mmHg at 100°C) to 100 parts of Tarim slag heated to a fluid state (properties shown in Table 1). 2 / s, flash point 212℃, by mass fraction, saturated fraction 33%, aromatic fraction 56.5%, resin 10%, asphaltene 0.5%; weight average molecular weight 2090, molecular weight distribution width 2.7), 3 parts linear SBS modifier and 3 parts star-shaped SBS modifier (linear SBS modifier accounts for 65wt% of the total, the linear SBS modifier has the following properties: styrene to butadiene mass ratio of 20:80, tensile strength 300kg / cm 2 The elongation at break is 820%, and the Shore hardness is 75HA. The star-shaped SBS modifier has the following properties: the mass ratio of styrene to butadiene is 40:60, and the tensile strength is 250 kg / cm². 2 The asphalt (with an elongation at break of 750% and a Shore hardness of 90 HA) was sheared at 180℃ and 4500 r / min for 50 min. After shearing, 0.15 parts of elemental sulfur and 0.07 parts of tetramethylthiuram disulfide were added, and the mixture was stirred and developed at 183℃ and 400 r / min for 7 h to obtain pre-modified asphalt.

[0086] (2) Take 100 parts of the pre-modified asphalt obtained in (1) and add 5.5 parts of maleic anhydride and 0.4 parts of dicumyl peroxide. Under the stirring speed of 650 r / min, the temperature is increased to 175℃ at a speed program of 2℃ / min. After the temperature is increased, the reaction is carried out under N2 atmosphere. The pressure in the reactor is maintained at 0.6 MPa and the reaction time is 7h.

[0087] (3) After cooling the material in (2), dissolve it completely in chloroform, add 12 parts of PEI with a molecular weight of 70,000 and 2.5 parts of triethylamine, and heat and reflux at 60°C for 16 hours to carry out the reaction. After the reaction is completed, add 1.5 parts of benzyl chloride (BC) and heat and reflux at 55°C for 22 hours. After the reaction is completed, the cationic asphalt composition A5 for drilling fluid is obtained.

[0088] Comparative Example 1

[0089] The process is the same as in Example 1, except that 100 parts of Tahe slag reducing agent heated to a fluid state (properties shown in Table 1) in step (1) are replaced with 100 parts of 70A base bitumen heated to a fluid state. The final product is cationic bitumen composition B1 for drilling fluid.

[0090] Comparative Example 2

[0091] The other steps are the same as in Example 1, except that the pre-modification treatment in step (1) of Tahe slag reduction is not performed, and 100 parts of Tahe slag reduction are directly used for steps (2) and (3). The final product is cationic bitumen composition B2 for drilling fluid.

[0092] Comparative Example 3

[0093] The procedure is the same as in Example 1, except that all operations in step (2) are omitted. The final product is a cationic bitumen composition B3 for drilling fluid.

[0094] Comparative Example 4

[0095] The procedure is the same as in Example 1, except that triethylamine is not added in step (3). The final product is a cationic bitumen composition B4 for drilling fluid.

[0096] Comparative Example 5

[0097] The procedure is the same as in Example 1, except that benzyl chloride is not added in step (3). The final product is a cationic bitumen composition B5 for drilling fluid.

[0098] Test case

[0099] The softening point, hydrophilicity, cationicity, and high-temperature high-pressure filtration loss of the drilling fluid cationic bitumen compositions obtained in the examples and comparative examples were tested. Before the high-temperature high-pressure filtration loss test, the compositions were first pulverized. 100g of the cryogenically frozen drilling fluid cationic bitumen composition (cryo-freezing conditions: temperature -32℃, time 10h) was added to a high-speed pulverizer and pulverized for 40s to obtain bitumen particles with an average particle size range of 80-100µm. The bitumen particles obtained in the examples and comparative examples were added to the prepared base slurry, with the amount of bitumen particles accounting for 2% of the weight of the base slurry. The filtration loss was measured after aging at different temperatures (16h) under a test pressure of 3.45MPa. The specific results are shown in Table 2. The base slurry was prepared as follows: 2.75g of anhydrous sodium carbonate was added to 1000mL of water, followed by 60g of bentonite. The mixture was stirred at high speed for 20 minutes and cured at room temperature for 24 hours to obtain a 6% fresh water base slurry.

[0100] The formula for calculating cationicity is as follows:

[0101]

[0102] In the formula:

[0103] Concentration of C1-tetraphenylborate sodium standard solution, mol / L;

[0104] V1—The volume of sodium tetraphenylborate standard solution added, in ml;

[0105] Concentration of C2-hexadecyltrimethylammonium bromide standard solution, mol / L;

[0106] V2 — The volume of hexadecyltrimethylammonium bromide standard solution consumed, in ml;

[0107] V0—The difference between the actual CTAB consumed and the theoretically required CTAB consumed in the blank control experiment, in ml;

[0108] m1—mass of the sample, in g;

[0109] y—Cation degree, mol / g.

[0110] Table 1. Properties of Tarim Basin Slag Reduction Materials Used in Examples and Comparative Cases

[0111]

[0112]

[0113] Table 2. Properties of the cationic bituminous drilling fluid compositions obtained in the examples and comparative examples.

[0114]

[0115] The scope of protection of this invention is not limited to the above embodiments, but is defined by the claims. Those skilled in the art can make appropriate modifications to these embodiments without departing from the technical concept and spirit of this invention, and these modified embodiments are also included within the scope of protection of this invention.

Claims

1. A cationic bitumen composition for drilling fluid, characterized in that, By weight, it includes the following raw material components: Pre-modified asphalt: 100 parts; Anhydride modifier: 2-10 parts; Initiator: 0.08~0.7 parts; Cationic modifier: 6-15 parts; Acid-binding agent: 2-6 parts; Quaternizing agent: 0.5~5 parts; The pre-modified asphalt is obtained by modifying inferior slag with a composite SBS modifier; The cationic bitumen composition for drilling fluid is prepared using the following method: (1) Preparation of pre-modified asphalt; (2) Add anhydride modifier and initiator to the pre-modified asphalt obtained in step (1), stir and heat to the reaction temperature, and carry out the reaction under protective gas; (3) Dissolve the material obtained in step (2) in chloroform, add cationic modifier and acid binder, and react under the first heating reflux condition; after the reaction is completed, add quaternizing agent and react under the second heating reflux condition to obtain a cationic asphalt composition for drilling fluid; In step (1), the preparation process of the pre-modified asphalt includes: Inferior slag is heated to a molten state, and compatibilizer and composite SBS modifier are added before shearing. After shearing, stabilizer is added, and the mixture is stirred and developed. After development, pre-modified asphalt is obtained.

2. The cationic bitumen composition for drilling fluid according to claim 1, characterized in that, The pre-modified asphalt, by weight, comprises the following raw material components: Inferior slag reduction: 100 portions; Compatibilizer: 3-6 parts; Composite SBS modifier: 5-7 parts; Stabilizer: 0.1~0.5 parts.

3. The cationic bitumen composition for drilling fluid according to claim 1, characterized in that, The cationic bitumen composition for drilling fluid comprises, by weight, the following raw material components: Pre-modified asphalt: 100 parts; Anhydride modifier: 2-8 parts; Initiator: 0.15~0.7 parts; Cationic modifier: 8-15 parts; Acid-binding agent: 2-5 parts; Quaternizing agent: 0.5~3 parts.

4. The cationic bitumen composition for drilling fluid according to claim 2, characterized in that, The pre-modified asphalt, by weight, comprises the following raw material components: Inferior slag reduction: 100 portions; Compatibilizer: 3.5~5 parts; Composite SBS modifier: 5~6.2 parts; Stabilizer: 0.15~0.4 parts.

5. The cationic bitumen composition for drilling fluid according to claim 1, 2, or 4, characterized in that, The properties of the inferior slag include: a flash point of 241℃~256℃, a sulfur content of 2.61wt%~3.65wt%, and by mass fraction, saturated components of 26.1%~37.7%, aromatic components of 20.2%~34.5%, resins of 18.3%~24.8%, and asphaltene of 21.3%~30.1%.

6. The cationic bitumen composition for drilling fluid according to claim 5, characterized in that, The inferior slag, by mass fraction, contains 21.3% to 26.0% asphalt.

7. The cationic bitumen composition for drilling fluid according to claim 5, characterized in that, The inferior slag also has the following properties: residual carbon value of 21wt%~29wt%, nitrogen content of 0.14wt%~0.61wt%, total nickel and vanadium content of 320~365μg / g, and condensation index CI of 0.26~0.

35.

8. The cationic bitumen composition for drilling fluid according to claim 2 or 4, characterized in that, The compatibilizer has the following properties: kinematic viscosity of 50 mmHg at 100°C. 2 / s~65mm 2 / s, flash point is 206℃~220℃, by mass fraction, saturated fraction accounts for 30%~42%, aromatic fraction accounts for 48%~57%, resin accounts for 8%~13%, asphaltene content is less than 2%; weight average molecular weight is 1990~2140, molecular weight distribution width is 1.6~3.

7.

9. The cationic bitumen composition for drilling fluid according to claim 1, 2, or 4, characterized in that, The composite SBS modifier includes linear SBS modifier and star-shaped SBS modifier; wherein the linear SBS modifier accounts for 45% to 70% of the total mass of the composite SBS modifier; and the star-shaped SBS modifier accounts for 30% to 55% of the total mass of the composite SBS modifier.

10. The cationic bitumen composition for drilling fluid according to claim 9, characterized in that, The linear SBS modifier has the following properties: a styrene to butadiene mass ratio of 12~20:80~88, and a tensile strength of 280~350 kg / cm². 2 The elongation at break is 800%~910%, and the Shore hardness is 75±6HA; and / or, the star-shaped SBS modifier has the following properties: the mass ratio of styrene to butadiene is 35~45:55~65, and the tensile strength is 200~300 kg / cm². 2 Its elongation at break is 720%~800%, and its Shore hardness is 90±5HA.

11. The cationic bitumen composition for drilling fluid according to claim 2 or 4, characterized in that, The stabilizer is one or a mixture of elemental sulfur and one or more of the following: tetramethylthiuram disulfide, disodium thiodipropionate, disodium thiodipropionate, di(tridecyl) thiodipropionate, distearate thiodipropionate, zinc hydroxystannate, hydroquinone, zinc dimethyl thiocarbamate, zinc stearate, and thiocarbamate.

12. The cationic bitumen composition for drilling fluid according to claim 11, characterized in that, The elemental sulfur accounts for 70% to 90% of the total amount of the stabilizer by weight.

13. The cationic bitumen composition for drilling fluid according to claim 1, characterized in that, The anhydride modifier is one or more of maleic anhydride, polyisobutylene succinic anhydride, methyl nadic anhydride, modified methyl nadic anhydride MNA-10, dodecenyl succinic anhydride, tung oil anhydride, polyazelite anhydride, polyglutaric anhydride, polyoxoanhydride, or hydrolyzed polymaleic anhydride.

14. The cationic bitumen composition for drilling fluid according to claim 1, characterized in that, The initiator is one or more of dicumyl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, sodium metabisulfite, azobisisobutyronitrile, azobisisoheptanenitrile, and cumyl hydroperoxide.

15. The cationic bitumen composition for drilling fluid according to claim 1, characterized in that, The cationic modifier is polyethyleneimine, and the polyethyleneimine is one or more of the molecular weight range of 1000 to 70000.

16. The cationic bitumen composition for drilling fluid according to claim 15, characterized in that, The molecular weight of the polyethyleneimine is one or more of 1000, 20000, and 70000.

17. The cationic bitumen composition for drilling fluid according to claim 1, characterized in that, The acid-binding agent is triethylamine and / or 4-dimethylaminopyridine.

18. The cationic bitumen composition for drilling fluid according to claim 1, characterized in that, The quaternizing agent is one or more of hexadecane bromide, iodomethane, and benzyl chloride.

19. The method for preparing the cationic bitumen composition for drilling fluid according to any one of claims 1-18, characterized in that, include: (1) Preparation of pre-modified asphalt; (2) Add anhydride modifier and initiator to the pre-modified asphalt obtained in step (1), stir and heat to the reaction temperature, and carry out the reaction under protective gas; (3) Dissolve the material obtained in step (2) in chloroform, add cationic modifier and acid binder, and react under the first heating reflux condition; after the reaction is completed, add quaternizing agent and react under the second heating reflux condition to obtain a cationic bitumen composition for drilling fluid.

20. The manufacturing method according to claim 19, characterized in that, In step (1), the preparation process of the pre-modified asphalt includes: Inferior slag is heated to a molten state, and compatibilizer and composite SBS modifier are added before shearing. After shearing, stabilizer is added, and the mixture is stirred and developed. After development, pre-modified asphalt is obtained.

21. The manufacturing method according to claim 19, characterized in that, In step (2), the stirring speed is 600~800 r / min; the reaction temperature is 160℃~180℃, and the reaction time is 6~8h; the heating to the reaction temperature is carried out by programmed heating at a rate of 1℃~3℃ / min; the protective gas is an inert gas and / or N2; the amount of the protective gas is such that the reaction pressure is maintained at 0.3~0.9MPa.

22. The manufacturing method according to claim 21, characterized in that, In step (2), the amount of protective gas is such that the reaction pressure is maintained at 0.5~0.9 MPa.

23. The manufacturing method according to claim 19, characterized in that, In step (3), the reaction temperature of the first heating reflux is 40℃~90℃ and the time is 10~16h; the reaction temperature of the second heating reflux is 40℃~80℃ and the time is 20~24h.

24. The manufacturing method according to claim 23, characterized in that, In step (3), the reaction temperature of the first heating reflux is 45℃~80℃, and the reaction temperature of the second heating reflux is 40℃~60℃.

25. The manufacturing method according to claim 23 or 24, characterized in that, In step (3), the reaction temperature of the second heating reflux is 10~20℃ lower than that of the first heating reflux.

26. The manufacturing method according to claim 19, characterized in that, In step (3), the reaction is carried out under the second heating reflux condition, and then cooled and evaporated to obtain a cationic bitumen composition for drilling fluid.

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