Cationic asphalt composition for drilling fluid and preparation method thereof

Abstract

The invention discloses a cationic asphalt composition for drilling fluid and a preparation method thereof. The cationic asphalt composition for the drilling fluid comprises the following raw material components in parts by weight: 100 parts of pre-modified asphalt; 2-10 parts of an anhydride modifier; 0.08 to 0.7 part of an initiator; 6 to 15 parts of a cationic modifier; 2-6 parts of an acid-binding agent; 0.5 to 5 parts of a quaternizing agent; wherein the pre-modified asphalt is obtained by modifying inferior reduced slag with a composite SBS modifier. According to the invention, the inferior reduced slag which is difficult to treat is taken as a raw material, and the modified asphalt which is high in softening point and good in hydrophilicity and shows cationic characteristics is obtained through modification treatment, and can be used as a cationic asphalt composition for drilling fluid for oil field drilling.

Description

Technical Field

[0001] The invention relates to an asphalt material and a preparation method thereof, and in particular to a cationic asphalt composition for drilling fluid and a preparation method thereof. Background Art

[0002] As the drilling field continues to expand, the application of asphalt plugging agents in oil field drilling has received more and more attention. Asphalt plugging agents generally contain asphalt particles that are insoluble in water and have a certain softening point. When the temperature and pressure in the wellbore are high enough, the asphalt particles soften and deform, and are squeezed into the microcracks of the well wall, preventing the drilling fluid from penetrating from the microcracks, and effectively plugging the formation together with the mud cake. Asphalt substances are extremely effective anti-collapse agents and oil layer protectors for oil drilling. For drilling operations in deep oil and gas fields, general softening point asphalt will not meet the high-temperature operation requirements in deep wells due to excessive softening or flow. High softening point asphalt (softening point above 100°C, especially asphalt above 120°C) can meet the requirements of deep drilling due to its excellent high temperature resistance.

[0003] As one of the important additives in drilling fluid, asphalt has been used in oilfield drilling operations for many years, and it mainly plays the role of plugging, preventing collapse and reducing filtration. Asphalt drilling fluid system is mainly oil-based, but oil-based drilling fluid has certain defects in cost and environmental protection. Water-based drilling fluid has received more and more attention. In recent years, water-based drilling fluid with cationic properties has gradually become popular in oil fields, but it is difficult to prepare asphalt materials with certain cationic properties and apply them to water-based drilling fluid.

[0004] As crude oil becomes heavier, the yield of vacuum residue oil increases gradually, the heavy metal content and sulfur content in the residue oil increase, the relative content of saturated components and asphaltene in the residue oil increases, the relative content of aromatic components and colloid decreases, and the degree of asphaltene association increases, and the existence form becomes more complex, which increases the difficulty of directly preparing inferior residue oil into high-grade asphalt. Therefore, for this type of increasingly inferior residue oil, if it can be modified and converted into asphalt particles with high softening point, good hydrophilicity and cationic properties, it can provide conditions for the preparation of asphalt-based water-based cationic drilling fluids.

[0005] CN104559247B discloses a method for preparing high-softening-point asphalt particles. In this method, two high-softening-point asphalts with different softening points are combined and granulated. During the granulation process, the asphalt particles are subjected to low-temperature embrittlement and inorganic micropowders and surfactants are introduced. The obtained high-softening-point asphalt particles can function under drilling operation conditions in a wide temperature range. However, the asphalt particles have poor hydrophilicity and can only be used in oil-based drilling fluid systems. In addition, the surface of the particles does not show cationic properties, and the effects of plugging, preventing collapse and reducing filtration in oil wells dominated by anions are average.

[0006] CN103805221B discloses a method for producing high-softening-point asphalt. The raw material of the method is a mixture of coal tar and petroleum asphalt. The oxidation reaction is promoted by utilizing the characteristics of coal tar such as low viscosity and high reaction activity at high temperature. However, the oxidation process of coal tar releases a large amount of toxic and harmful gases, which are harmful to the environment and human body. In addition, the prepared high-softening-point asphalt does not have hydrophilic properties and cannot be used as a raw material for preparing asphalt-based water-based drilling fluid.

[0007] CN1415699A discloses a method for producing oxidized asphalt, which first uses a static mixer to mix air and asphalt, so that the air is dispersed into the asphalt raw material in the form of tiny bubbles, and then enters an oxidation device for oxidation reaction. This method can adjust the asphalt properties when producing ordinary road asphalt and building asphalt, but is not suitable for producing high softening point asphalt. Because the amount of air in the asphalt at high temperature is very small, the oxidation efficiency is limited, the softening point of the asphalt cannot be greatly improved, and coking occurs in the production process.

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

[0009] In view of the shortcomings of the prior art, the present invention provides a cationic asphalt composition for drilling fluid and a preparation method thereof. The present invention uses difficult-to-treat inferior reduced slag as raw material, and obtains a modified asphalt with high softening point, good hydrophilicity and cationic properties through modification treatment, which can be used as a cationic asphalt composition for drilling fluid for oil field drilling.

[0010] The first aspect of the present invention provides a cationic asphalt composition for drilling fluid, which comprises the following raw material components in parts by weight:

[0011] Pre-modified asphalt: 100 parts;

[0012] Acid 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 reduced slag with a composite SBS modifier.

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

[0019] Inferior quality reduced residue: 100 parts;

[0020] Compatibilizer: 3-6 parts;

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

[0022] Stabilizer: 0.1-0.5 parts.

[0023] The cationic asphalt composition for drilling fluid comprises the following raw material components in parts by weight:

[0024] Pre-modified asphalt: 100 parts;

[0025] Acid 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] Quaternizing agent: 0.5 to 3 parts.

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

[0031] Inferior quality reduced residue: 100 parts;

[0032] Compatibilizer: 3.5-5 parts;

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

[0034] Stabilizer: 0.15-0.4 parts.

[0035] The properties of the inferior reduced slag include: a flash point of 241°C to 256°C, a sulfur content of 2.61wt% to 3.65wt%, and by mass fraction, saturated components account for 26.1% to 37.7%, aromatic components account for 20.2% to 34.5%, colloids account for 18.3% to 24.8%, asphaltenes account for 21.3% to 30.1%, and asphaltenes preferably account for 21.3% to 26.0%.

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

[0037] The inferior minced slag may be Tahe minced slag and / or other minced slag satisfying the above properties, and the inferior minced slag is a fraction having an initial distillation point greater than 425°C.

[0038] The compatibilizer is a colloid obtained through a conventional solvent deasphalting process in the art.

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

[0040] The composite SBS modifier includes a linear SBS modifier and a 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.

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

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

[0043] The stabilizer is a mixture of elemental sulfur and one or more of tetramethylthiuram disulfide, didodecanol thiodipropionate, distearyl thiodipropionate, zinc hydroxystannate, hydroquinone, zinc dimethylthiocarbamate, zinc stearate, and thiocarbamate. Preferably, based on the weight of the stabilizer, the elemental sulfur accounts for 70% to 90% of the total amount of the stabilizer.

[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, polyazelaic anhydride, polyglutaric anhydride, polyoxalic anhydride or hydrolyzed polymaleic anhydride.

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

[0046] The cationic modifier is polyethyleneimine, and the polyethyleneimine has a molecular weight of one or more of 1000 to 70000, preferably a molecular weight of one or more of 1000, 20000, and 70000.

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

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

[0049] The second aspect of the present invention provides a method for preparing the above-mentioned cationic asphalt composition for drilling fluid, comprising:

[0050] (1) preparing pre-modified asphalt;

[0051] (2) adding an anhydride modifier and an initiator to the pre-modified asphalt obtained in step (1), stirring and heating to a reaction temperature, and reacting under a protective gas;

[0052] (3) The material obtained in step (2) is fully dissolved in chloroform, a cationic modifier and an acid binding agent are added, and the reaction is carried out under a first heating reflux condition; after the reaction is completed, a quaternary ammonium agent is added, and the reaction is carried out under a second heating reflux condition to obtain a cationic asphalt composition for drilling fluid.

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

[0054] The inferior slag is heated to a molten state, and shearing is performed after adding a compatibilizer and a composite SBS modifier. After the shearing, a stabilizer is added, and the mixture is stirred and developed. After the 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, the required temperature during shearing is 160° C.-185° C., preferably 170° C.-185° C. The developing temperature is 180° C.-195° C., and the developing 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 6-8h. The heating to the reaction temperature is preferably carried out by programmed heating to the reaction temperature, and the heating rate is 1°C-3°C / 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 0.3-0.9 MPa, preferably 0.5-0.9 MPa.

[0057] In step (3), the reaction temperature of the first heating reflux is 40°C to 90°C, preferably 45°C to 80°C, and the time is 10 to 16 hours; the reaction temperature of the second heating reflux is 40°C to 80°C, preferably 40°C to 60°C, and the time is 20 to 24 hours. Preferably, the reaction temperature of the second heating reflux is 10 to 20°C lower than the reaction temperature of the first heating 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 asphalt composition for drilling fluid, wherein the rotary evaporation is for removing the organic solvent.

[0059] The cationic asphalt composition for drilling fluid needs to be cryogenically frozen and crushed before use.

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

[0061] The pulverizing process is carried out in a high-speed shearing pulverizer, a colloid mill, a ball mill pulverizer and the like, and the pulverizing time is 30 to 100 seconds, preferably 30 to 60 seconds.

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

[0063] (1) The inferior asphalt residue used in the present invention is a low-value-added raw material, which is not suitable for producing modified asphalt for drilling fluid. For example, the Tahe asphalt residue has a high asphaltene content, a very special form, and extremely inferior comprehensive performance. However, through the coordinated coordination of various raw materials in the present invention, comprehensive modification is carried out, and it can be used to prepare high softening point asphalt for drilling fluid, which expands the use of inferior raw materials and improves their added value.

[0064] (2) The present invention adopts a three-stage modification method of polymer pre-modification - anhydride modification - cationic modification. The three modification methods cooperate with each other and promote each other, which greatly improves the softening point, hydrophilicity and cationic properties of asphalt. On the basis of maintaining the original viscoelastic properties of asphalt, its sealing ability in high temperature and water-based environment is increased, making it more suitable for the field of drilling fluid asphalt.

[0065] (3) The present invention selects special raw materials and preparation and modification methods. The obtained cationic asphalt composition for drilling fluid not only has a high softening point and good hydrophilicity, but also can show cationic properties in an aqueous environment. In addition, the prepared product has less sticky components after solvent recovery and drying, and shows obvious hardness and brittleness. Further freezing and crushing can obtain modified asphalt particles with uniform particle size, which reduces the difficulty of crushing. DETAILED DESCRIPTION

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

[0067] In the present invention, the softening point is tested according to the requirements of "Test Procedure for Asphalt and Asphalt Mixture in Highway Engineering JTG E20-2011", the contact angle is measured by OCA25 video optical contact angle measuring instrument developed and produced by German dataphysics company, the high temperature and high pressure filtration loss is measured according to SY / T5621 method, and the cationic degree is measured by sodium tetraphenylborate back titration method.

[0068] Example 1

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

[0070] (2) Take 100 parts of the pre-modified asphalt obtained in (1), add 5 parts of maleic anhydride and 0.5 parts of diisopropylbenzene peroxide, and heat to 175°C at a rate of 2°C / min under a stirring speed of 650 r / min. After the heating is completed, react in a N2 atmosphere. The pressure in the reactor is maintained at 0.6 MPa and the reaction time is 6 h.

[0071] (3) The material obtained in (2) was cooled and fully dissolved in chloroform, and 10 parts of polyethyleneimine with a molecular weight of 70,000 and 3 parts of triethylamine were added. The mixture was heated under reflux at 60°C for 12 hours to react. After the reaction, 1 part of benzyl chloride (BC) was added and the mixture was heated under reflux at 50°C for 24 hours. After the reaction, a cationic asphalt composition A1 for drilling fluid was obtained.

[0072] Example 2

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

[0074] (2) Take 100 parts of the pre-modified asphalt obtained in (1), add 4 parts of maleic anhydride and 0.25 parts of diisopropylbenzene peroxide, and heat to 175°C at a rate of 2°C / min under a stirring speed of 650 r / min. After the heating is completed, react in a N2 atmosphere. The pressure in the reactor is maintained at 0.6 MPa and the reaction time is 6 h.

[0075] (3) The material obtained in (2) is cooled and fully dissolved in chloroform, and 10 parts of polyethyleneimine with a molecular weight of 20,000 and 3 parts of triethylamine are added. The mixture is heated under reflux at 60°C for 12 hours for reaction. After the reaction, 1 part of benzyl chloride (BC) is added, and the mixture is heated under reflux at 50°C for 24 hours. After the reaction, a cationic asphalt composition A2 for drilling fluid is obtained.

[0076] Example 3

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

[0078] (2) Take 100 parts of the pre-modified asphalt obtained in (1), add 5 parts of maleic anhydride and 0.5 parts of diisopropylbenzene peroxide, and heat to 175°C at a rate of 2°C / min under a stirring speed of 650 r / min. After the heating is completed, react in a N2 atmosphere. The pressure in the reactor is maintained at 0.6 MPa and the reaction time is 6 h.

[0079] (3) The material in (2) was cooled and fully dissolved in chloroform, and 10 parts of PEI with a molecular weight of 70,000 and 3 parts of triethylamine were added. The mixture was heated under reflux at 60° C. for 12 h to react. After the reaction, 1 part of benzyl chloride (BC) was added and the mixture was heated under reflux at 50° C. for 24 h. After the reaction, a cationic asphalt composition A3 for drilling fluid was obtained.

[0080] Example 4

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

[0082] (2) Take 100 parts of the pre-modified asphalt obtained in (1), add 5 parts of maleic anhydride, 2 parts of methyl nadic anhydride and 0.45 parts of azobisisobutyronitrile, and heat to 175°C at a rate of 2°C / min under a stirring speed of 650 r / min. After the heating is completed, react in a N2 atmosphere. The pressure in the reactor is maintained at 0.6 MPa and the reaction time is 6 h.

[0083] (3) The material obtained in (2) is cooled and fully dissolved in chloroform, and 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 are added, and the mixture is heated under reflux at 60°C for 12 hours for reaction. After the reaction, 1 part of benzyl chloride (BC) and 0.5 parts of iodomethane (IMT) are added, and the mixture is heated under reflux at 50°C for 24 hours. After the reaction, a cationic asphalt composition A4 for drilling fluid is obtained.

[0084] Example 5

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

[0086] (2) Take 100 parts of the pre-modified asphalt obtained in (1), add 5.5 parts of maleic anhydride and 0.4 parts of diisopropylbenzene peroxide, and heat to 175°C at a rate of 2°C / min under a stirring speed of 650 r / min. After the heating is completed, react in a N2 atmosphere. The pressure in the reactor is maintained at 0.6 MPa and the reaction time is 7 h.

[0087] (3) The material in (2) was cooled and fully dissolved in chloroform, 12 parts of PEI with a molecular weight of 70,000 and 2.5 parts of triethylamine were added, and the mixture was heated under reflux at 60°C for 16 hours for reaction. After the reaction, 1.5 parts of benzyl chloride (BC) was added, and the mixture was heated under reflux at 55°C for 22 hours. After the reaction, a cationic asphalt composition A5 for drilling fluid was obtained.

[0088] Comparative Example 1

[0089] The other steps are the same as those in Example 1, except that 100 parts of Tahe slag heated to a fluid state (properties shown in Table 1) in step (1) are replaced with 100 parts of 70A base asphalt heated to a fluid state. Finally, a cationic asphalt composition B1 for drilling fluid is obtained.

[0090] Comparative Example 2

[0091] The other steps are the same as those in Example 1, except that the Tahe slag is not subjected to the pre-modification treatment in step (1), and 100 parts of the Tahe slag are directly used to carry out steps (2) and (3). Finally, a cationic asphalt composition B2 for drilling fluid is obtained.

[0092] Comparative Example 3

[0093] The rest is the same as in Example 1, except that all operations in step (2) are omitted. Finally, a cationic asphalt composition B3 for drilling fluid is obtained.

[0094] Comparative Example 4

[0095] The other steps are the same as those in Example 1, except that triethylamine is not added in step (3). Finally, a cationic asphalt composition B4 for drilling fluid is obtained.

[0096] Comparative Example 5

[0097] The other steps are the same as those in Example 1, except that benzyl chloride is not added in step (3). Finally, a cationic asphalt composition B5 for drilling fluid is obtained.

[0098] Test Case

[0099] The cationic asphalt compositions for drilling fluid obtained in the embodiments and comparative examples were tested for softening point, hydrophilicity, cationic degree, and high-temperature and high-pressure filtration loss. Before the high-temperature and high-pressure filtration loss test, the composition was crushed. 100g of the cationic asphalt composition for drilling fluid treated with low-temperature freezing (low-temperature freezing conditions: temperature -32°C, time 10h) was added to a high-speed crusher and crushed for 40s to obtain asphalt particles with an average particle size range of 80 to 100um. The asphalt particles obtained in the embodiments and comparative examples were added to the prepared base slurry, and the amount of asphalt particles added accounted for 2% of the weight of the base slurry. The filtration loss after aging at different temperatures (16h) was measured under the test pressure of 3.45MPa. The specific results are shown in Table 2. The base slurry preparation method is as follows: 2.75g of anhydrous sodium carbonate was added to 1000mL of water, and then 60g of bentonite was added. 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 calculation formula of cationicity is as follows:

[0101]

[0102] Where:

[0103] C1—concentration of sodium tetraphenylborate standard solution, mol / L;

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

[0105] C2—concentration of hexadecyltrimethylammonium bromide standard solution, mol / L;

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

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

[0108] m1—mass of the sample, g;

[0109] y—cationic degree, mol / g.

[0110] Table 1 Properties of Tahe slag used in Examples and Comparative Examples

[0111]

[0112]

[0113] Table 2 Properties of the cationic asphalt compositions for drilling fluid obtained in Examples and Comparative Examples

[0114]

[0115] The protection scope of the present invention is not limited by the above embodiments, but by the claims. Those skilled in the art may make appropriate changes to these embodiments without departing from the technical concept and purpose of the present invention, and these changed embodiments are also included in the protection scope of the present invention.

Claims

1. A cationic asphalt composition for drilling fluid, characterized in that: By weight, it includes the following raw material components: Pre-modified asphalt: 100 parts; Acid 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 reduced slag with a composite SBS modifier.

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

3. The cationic asphalt composition for drilling fluid according to claim 1, characterized in that: The cationic asphalt composition for drilling fluid comprises the following raw material components in parts by weight: Pre-modified asphalt: 100 parts; Acid 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 to 3 parts.

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

5. The cationic asphalt composition for drilling fluid according to claim 1, 2 or 4, characterized in that: The properties of the inferior reduced slag include: a flash point of 241°C to 256°C, a sulfur content of 2.61wt% to 3.65wt%, and by mass fraction, saturated components account for 26.1% to 37.7%, aromatic components account for 20.2% to 34.5%, colloids account for 18.3% to 24.8%, asphaltenes account for 21.3% to 30.1%, and asphaltenes preferably account for 21.3% to 26.0%.

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

35.

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

7.

8. The cationic asphalt composition for drilling fluid according to claim 1, 2 or 4, characterized in that: The composite SBS modifier comprises a linear SBS modifier and a 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.

9. The cationic asphalt composition for drilling fluid according to claim 8, characterized in that: The linear SBS modifier has the following properties: the mass content ratio of styrene to butadiene is 12-20:80-88, and the tensile strength is 280-350 kg / cm 2 , elongation at break of 800% to 910%, Shore hardness of 75±6HA; and / or, the star-shaped SBS modifier has the following properties: the mass content ratio of styrene to butadiene is 35 to 45:55 to 65, the tensile strength is 200 to 300 kg / cm 2 , the elongation at break is 720%~800%, and the Shore hardness is 90±5HA.

10. The cationic asphalt composition for drilling fluid according to claim 2 or 4, characterized in that: The stabilizer is a mixture of elemental sulfur and one or more of tetramethylthiuram disulfide, didodecanol thiodipropionate, distearyl thiodipropionate, zinc hydroxystannate, hydroquinone, zinc dimethylthiocarbamate, zinc stearate, and thiocarbamate; preferably, based on the weight of the stabilizer, the elemental sulfur accounts for 70% to 90% of the total amount of the stabilizer.

11. The cationic asphalt 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, polyazelaic anhydride, polyglutaric anhydride, polyoxalic anhydride or hydrolyzed polymaleic anhydride.

12. The cationic asphalt 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 pyrosulfite, azobisisobutyronitrile, azobisisoheptanenitrile and cumene hydroperoxide.

13. The cationic asphalt composition for drilling fluid according to claim 1, characterized in that: The cationic modifier is polyethyleneimine, and the polyethyleneimine has a molecular weight of one or more of 1000 to 70000, preferably a molecular weight of one or more of 1000, 20000, and 70000.

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

15. The cationic asphalt composition for drilling fluid according to claim 1, characterized in that: The quaternizing agent is one or more of hexadecane bromide, methyl iodide and benzyl chloride.

16. The method for preparing the cationic asphalt composition for drilling fluid according to any one of claims 1 to 15, characterized in that: include: (1) preparing pre-modified asphalt; (2) adding an anhydride modifier and an initiator to the pre-modified asphalt obtained in step (1), stirring and heating to a reaction temperature, and reacting under a protective gas; (3) The material obtained in step (2) is fully dissolved in chloroform, a cationic modifier and an acid binding agent are added, and the reaction is carried out under a first heating reflux condition; after the reaction is completed, a quaternary ammonium agent is added, and the reaction is carried out under a second heating reflux condition to obtain a cationic asphalt composition for drilling fluid.

17. The method according to claim 16, characterized in that: In step (1), the preparation process of the pre-modified asphalt includes: The inferior slag is heated to a molten state, and shearing is performed after adding a compatibilizer and a composite SBS modifier. After the shearing, a stabilizer is added, and the mixture is stirred and developed. After the development, pre-modified asphalt is obtained.

18. The method according to claim 16, characterized in that: 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; the heating to the reaction temperature is preferably carried out by programmed heating to the reaction temperature, and the heating rate is 1°C-3°C / 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 0.3-0.9 MPa, preferably 0.5-0.9 MPa.

19. The method according to claim 16, characterized in that: In step (3), the reaction temperature of the first heating reflux is 40°C to 90°C, preferably 45°C to 80°C, and the time is 10 to 16 hours; the reaction temperature of the second heating reflux is 40°C to 80°C, preferably 40°C to 60°C, and the time is 20 to 24 hours; preferably, the reaction temperature of the second heating reflux is 10 to 20°C lower than the reaction temperature of the first heating reflux.

20. The method according to claim 16, characterized in that: In step (3), the reaction is carried out under the second heating reflux condition, and then cooled and rotary evaporated to obtain a cationic asphalt composition for drilling fluid.

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