Emulsified asphalt plugging and anti-collapse agent and preparation method thereof

Abstract

The present application provides an emulsified asphalt plugging and anti-collapse agent and a preparation method thereof, which belongs to the field of drilling engineering technology. The emulsified asphalt plugging and anti-collapse agent is an emulsion obtained by emulsifying asphalt powder, nanoemulsion and dispersant under high temperature conditions through a colloid mill; the emulsified asphalt plugging and anti-collapse agent has a high softening point, a finer particle size distribution, good shale inhibition, lubricity, plugging and anti-collapse properties and filtration loss reduction properties. Adding it to water-based drilling fluid can significantly reduce the filtration loss of drilling fluid, improve the high-temperature stability of water-based drilling fluid, and have strong resistance to high-pressure composite brine pollution. Under high-temperature formation conditions of 130-150°C, the addition of this high-softening-point emulsified asphalt plugging and anti-collapse agent can significantly improve the plugging and anti-collapse performance of water-based drilling fluid, especially in high-temperature deep well fractured formations with good plugging and anti-collapse effects.

Description

Technical Field

[0001] The present application relates to the technical field of drilling engineering, and in particular to an emulsified asphalt plugging and anti-collapse agent and a preparation method thereof. Background Art

[0002] Deep and ultra-deep oil and gas resources have gradually become the key areas of exploration and development in my country. During the drilling of deep and ultra-deep wells, the open hole section is long, and the probability of encountering complex formations is increasing. In particular, in some areas, tectonic movements have caused the development of formation fault zones, which can easily lead to well wall instability during the drilling process. Supplementing emulsified asphalt plugging and anti-collapse agents to improve the drilling fluid's ability to seal and consolidate the wall is an important guarantee for maintaining the stability of the open hole wall and reducing drilling complexity.

[0003] Emulsified asphalt is made by heating viscous asphalt to a fluid state, then mechanically forming droplets that are dispersed in water containing an emulsifier and stabilizer to create a uniform, stable emulsion. Emulsified asphalt is used in drilling fluids as a slump-proof and fluid loss treatment agent. Its products are diverse and complex in composition. Natural or petroleum-based asphalt is rarely used in oil drilling. Most asphalt is emulsified or modified in various ways, with the selection of different products tailored to the specific application. However, the raw material for traditional emulsified asphalt is primarily petroleum-based asphalt, which has a relatively low softening point. Consequently, the softening point of the resulting emulsified asphalt is also generally low, typically below 60°C. When the formation temperature exceeds the softening point, the sealing and anti-slump capabilities of traditional emulsified asphalt gradually diminish.

[0004] The use of asphalt-based high-temperature resistant, deformable plugging and anti-slumping agents (such as sulfonated asphalt powder, modified asphalt powder, and emulsified asphalt) is primarily determined by the relationship between the asphalt's softening point and formation temperature. The optimal use condition for asphalt-based high-temperature resistant plugging and anti-slumping agents to match formation temperature is that the softening point of the asphalt in the plugging and anti-slumping agent should be at least equal to the formation temperature. That is, when the formation temperature is 130°C, asphalt with a softening point of approximately 130°C should be selected for the asphalt-based plugging and anti-slumping agent. This is mainly because: the mechanism of action of asphalt-based high-temperature resistant plugging and anti-collapse agents mainly relies on the softening and deformation of asphalt materials at high temperatures to seal microcracks; when the formation temperature is much higher than the softening point of the selected asphalt-based materials, the asphalt-based materials will gradually turn into "liquid droplets" or form "oil droplets" at the formation temperature. At this time, the plugging ability of the asphalt-based high-temperature resistant plugging and anti-collapse agents mainly relies on the plugging effect of "oil droplets", and the plugging mechanism of "oil droplets" will become a plugging mechanism that relies on the Jamin effect, and the plugging effect is greatly reduced. Therefore, when using asphalt-based high-temperature resistant plugging and anti-collapse agents, they should be allowed to "limitedly deform" under the action of temperature. Only in this way can the asphalt-based high-temperature resistant plugging and anti-collapse agents play their role in improving mud cake quality and effectively sealing microcracks.

[0005] Chinese invention patent CN201611106756.X discloses a highly efficient plugging drilling fluid anti-collapse agent, a production method, and its use. The highly efficient plugging drilling fluid anti-collapse agent comprises a slow-cracking cationic emulsified asphalt, an anti-emulsifier, and a softening point modifier. The slow-cracking emulsifier, anti-emulsifier, and water are first prepared into a soap solution and acidified. The acidified soap solution and asphalt are then ground using a colloid mill to produce the slow-cracking cationic emulsified asphalt. During drilling operations, the emulsified asphalt and the softening point modifier are added to a water-based drilling fluid and uniformly mixed using high-speed shearing to produce a highly efficient plugging drilling fluid. The highly efficient plugging drilling fluid anti-collapse agent described in this invention has the advantages of good water solubility, strong anti-emulsification ability, an adjustable softening point, and significant plugging and anti-collapse effects. However, the agent's maximum temperature resistance is only 130°C.

[0006] Chinese invention patent 200510200450.6 discloses a cationic asphalt anti-slump agent latex, which is composed, by weight, of 40% to 56% asphalt, 0% to 10% of a softening point modifier, 0.7% to 3.0% of an emulsifying dispersant, 0% to 16% of a fluid loss additive, and the remainder being water. The cationic asphalt anti-slump agent latex in this invention features a high asphalt content (greater than 40%), good positive water solubility (similar to the effect of ink added to water, uniform and without precipitation), excellent anti-slump and fluid loss reduction effects, and low cost. The invention not only solves the problem of asphalt being difficult to dissolve in water-based drilling fluid systems, but also utilizes asphalt's inherent adhesion, leak-proofing, and anti-slump properties to address well wall stripping, loosening, and collapse in the drilling industry. The invention also features good water solubility, a high asphalt content, excellent plugging and fluid loss reduction effects, and a specific softening point. However, the softening point of the emulsified asphalt described in this invention is between 40-100° C., which limits its application effect in deep well fractured formations.

[0007] Chinese invention patent CN201711452849.2 discloses a grafted modified starch anti-collapse agent for drilling fluid and its preparation method. The anti-collapse agent is a natural modified product obtained by grafting reaction of components including starch, hydrophobic monomers, alkenyl amides, and alkenyl quaternary ammonium salts. The modified starch provided by the invention is an inhibitor with a hydrophobic group on the side chain of the molecule, which can be adsorbed on the surface of easily hydrated clay minerals to improve their hydrophobicity. The introduction of quaternary ammonium salts can increase the adsorption of molecules on the clay surface, effectively inhibit the hydration and dispersion of shale, and maintain the stability of the well wall. However, this technology is mainly used to inhibit the hydration and dispersion of clay and rock cuttings on the well wall, and has little effect on plugging properties, and has not been designed and modified for high temperature and other conditions.

[0008] The article "Development and Performance Evaluation of High-Temperature-Resistant Cationic Emulsified Asphalt for Drilling Fluids" (Wu Yan et al., Fault Block Oil and Gas Field) reports a high-temperature-resistant cationic emulsified asphalt for drilling fluids. With a temperature resistance of 150°C and a particle size of 0.50-175.00 μm, it meets the requirements for plugging high-temperature, micron-sized cracks in the deep and medium formations of Nanpu. First, JYEA-1 cationic slow-cracking emulsifier was added to 55°C hot water and the pH was adjusted to 5-6 to form a soap solution. 90# petroleum asphalt was heated to 140°C. The soap solution and hot-melt asphalt were transferred to an MD-1 colloid mill according to the equipment flow. After high-speed grinding, shearing, and cyclic emulsification, the cationic emulsified base asphalt was obtained after cooling. Next, the specialty asphalt was heated to 170°C and the JYEA-2 cationic slow-cracking emulsifier soap solution and the specialty asphalt were milled and emulsified using a DMV-005 colloid mill. After cooling, the cationic emulsified specialty asphalt was obtained. Finally, the cationic emulsified base asphalt, cationic emulsified specialty asphalt, and high-temperature resistant elastomer emulsion were blended and sheared using a DMV-005 colloid mill at 3000 r / min to obtain high-temperature resistant cationic emulsified asphalt. However, the preparation process of the emulsified asphalt prepared using this method is complex. Later in the preparation process, during the blending of the cationic emulsified base asphalt, cationic emulsified specialty asphalt, and high-temperature resistant elastomer emulsion, the mixture is susceptible to temperature differences among the mixed liquids, resulting in uneven particle size of the prepared cationic emulsified asphalt. The resulting emulsified asphalt particles are relatively large, making it difficult to plug smaller microcracks and micropores in complex formations. Consequently, the emulsified asphalt's effectiveness in deep well drilling in fractured formations is limited, resulting in suboptimal inhibition, lubricity, and anti-slump plugging.

[0009] The article "Recycling Oily Sludge into a Plugging and Collapse-Preventing Agent for Drilling Fluid and Its Application" (Chai Jinpeng et al., Journal of China University of Petroleum) reports on a plugging and collapse-preventing agent, SD-AS. This agent is prepared by mixing natural asphalt and oily sludge in a specific proportion at high temperature, adjusting the softening point with a softening point modifier such as high-softening-point asphalt, and then compounding it with cationic and nonionic surfactants to ensure the emulsification stability of the oily sludge and natural asphalt composite. A high-molecular-weight polymer is then added as a protective colloid to improve the dispersion stability of the oily sludge and natural asphalt composite. This product achieves effective plugging and collapse prevention primarily through chemical adsorption, physical plugging with oil-soluble deformable particles, retardation of pressure transmission, and reduction of the hydrophilicity of the shale surface. However, this product only regulates the softening point between 50°C and 120°C.

[0010] In summary, the softening point of the products prepared by the existing preparation of emulsified asphalt plugging and anti-collapse agents is generally low, which limits the application of emulsified asphalt in high-temperature formation well sections. In addition, the existing process flow for preparing high-softening-point emulsified asphalt is relatively complicated, and the prepared emulsified asphalt particles are large, which restricts its plugging effect in well sections with developed microcracks and micropores. Summary of the Invention

[0011] Based on the shortcomings of the existing technology, this application takes improving the softening point, preparation process, product particle size and comprehensive efficacy of asphalt substances in emulsified asphalt plugging and anti-collapse agents as the starting point, designs a preparation method for high-softening-point emulsified asphalt suitable for water-based drilling fluid and completion fluid, and designs and prepares a new type of emulsified asphalt plugging and anti-collapse agent.

[0012] The purpose of the present invention is to provide a high-softening-point emulsified asphalt plugging and anti-collapse agent that can be used in high-temperature formations (130-150°C) and has good shale inhibition, lubricity and plugging and anti-collapse properties. The emulsified asphalt plugging and anti-collapse agent can significantly reduce the filtration loss of water-based drilling fluids, improve the mud cake quality of water-based drilling fluids, and increase the lubricity of water-based drilling fluids. It is also an emulsified asphalt plugging and anti-collapse agent for drilling fluids and completion fluids that has certain shale inhibition performance and high-temperature stability.

[0013] In order to achieve the above object, the present invention adopts the following technical solutions:

[0014] The invention discloses an emulsified asphalt plugging and anti-collapse agent, which is obtained by emulsifying asphalt powder, nanoemulsion and dispersant through a colloid mill under high temperature conditions.

[0015] The mass ratio of the asphalt powder, nanoemulsion and dispersant is 3-4:1.8-2.2:0.25-0.35; preferably 3.85:2.0:0.3.

[0016] The high temperature is 60-70°C.

[0017] The emulsified asphalt plugging and anti-collapse agent is a stable emulsion.

[0018] Wherein: the distribution range of the median particle size D50 of the asphalt powder is 2-40 μm, and the softening point temperature is 130-150°C;

[0019] The nanoemulsion is n-octane nanoemulsion or paraffin nanoemulsion.

[0020] The preparation method of the n-octane nanoemulsion comprises the following steps:

[0021] (1) GTN cationic gemini surfactant and Tween 80 as main surfactants and n-butanol as co-surfactant were mixed as surfactant components at 55-60° C. and cooled for later use;

[0022] (2) n-octane is used as the oil phase and added to the surfactant component to form a mixed solution; NaCl solution is used as the water phase, and at an emulsification temperature of 25°C and an agent-oil ratio Ros of 6.5-7.5:2.8-3.2, the NaCl solution is added dropwise into the mixed solution to obtain an O / W type n-octane nanoemulsion.

[0023] The GTN cationic gemini surfactant described in the above step (1) is a commercial product with the product number GTN, and the purchase manufacturer is Zhengzhou Yihe Fine Chemicals Co., Ltd.

[0024] The mass ratio of the GTN cationic gemini surfactant, Tween 80 and n-butanol in the above step (1) is 45.5-52.5:47.5-54.5:20-30; preferably 47:53:25.5.

[0025] The mass ratio of n-octane to the surfactant component in the above step (2) is 15-20:35-55; preferably 16.8:39.1.

[0026] The preparation method of the paraffin nanoemulsion comprises the following steps:

[0027] Liquid paraffin, Span 80, Tween 80 and n-butanol were weighed and mixed with water, and then cationic gemini surfactant GTN was added and stirred evenly to form a paraffin nanoemulsion.

[0028] The mass of the liquid paraffin is the same as the total amount of Span 80 and Tween 80; the mass ratio of Span 80 to Tween 80 is 1:1; and the amount of n-butanol added is 0.25-0.35.

[0029] The volume ratio of the total mass of the liquid paraffin, Span 80, Tween 80 and n-butanol to water is 20-25:8.5-13.5 (g / mL); preferably 23:10 (g / mL).

[0030] The added amount of the cationic gemini surfactant GTN is 1.5% of the total mass.

[0031] The dispersant is a homemade comb-type polycarboxylate dispersant.

[0032] The preparation method of the self-made comb-shaped polycarboxylate dispersant comprises the following steps:

[0033] Sodium p-styrene sulfonate, allyl alcohol polyoxyethylene ether APEG600 and methacryloyloxyethyl trimethylammonium chloride were weighed separately, prepared into a deionized water solution, poured into a 250 mL three-necked flask, stirred at high speed to dissolve, and then added ammonium persulfate to the reactor. Deionized water was added to control the total monomer concentration to 30-35%. Stir and heat to 35-45 ° C. After deoxygenation with N2 for 30 minutes, the temperature was raised to 70-80 ° C. and reacted for 4-6 hours to obtain a brown thin colloid. After separation and purification, and after removing water in a vacuum at 90 ° C, a comb-type polycarboxylate strong dispersant was obtained.

[0034] The mass ratio of the sodium styrene sulfonate, allyl alcohol polyoxyethylene ether APEG600 and methacryloyloxyethyl trimethylammonium chloride is 0.35-0.55:0.8-1.2:0.05-0.35; preferably 0.45:0.9:0.15.

[0035] The volume ratio of the total mass of the sodium styrene sulfonate, allyl alcohol polyoxyethylene ether APEG600 and methacryloyloxyethyl trimethylammonium chloride to deionized water is 30:100 (g / mL).

[0036] The speed of the high-speed stirring is 300-350r / min.

[0037] The ratio of the added amount of ammonium persulfate to the total mass of sodium styrene sulfonate, allyl alcohol polyoxyethylene ether APEG600 and methacryloyloxyethyl trimethylammonium chloride is 0.05-5:100.

[0038] In some specific embodiments, the emulsified asphalt plugging and anti-collapse agent is prepared by the following method:

[0039] Take n-octane nanoemulsion, heat it to 60-70°C, start a colloid mill, pour the heated n-octane nanoemulsion into the colloid mill, add a homemade comb-type polycarboxylate dispersant, and pre-shear emulsification for 10-15 minutes; then pour asphalt powder into the colloid mill, and shear emulsify it with the n-octane nanoemulsion under the shear action of the colloid mill for 2-3 hours. Remove the fluid from the colloid mill to obtain an emulsified asphalt plugging and anti-collapse agent based on n-octane nanoemulsion; the effective content of high softening point asphalt in the emulsified asphalt plugging and anti-collapse agent is 45-65%;

[0040] The mass ratio of the n-octane nanoemulsion, the homemade comb-type polycarboxylate dispersant and the asphalt powder is 4:0.36:2.2.

[0041] or,

[0042] A paraffin nanoemulsion is heated in a water bath to 60-70°C, and a colloid mill is started. The heated paraffin nanoemulsion is poured into the colloid mill, and a homemade comb-type polycarboxylate dispersant is added. The mixture is sheared and emulsified for 10-15 minutes. Asphalt powder is then weighed and poured into the colloid mill. Under the shear action of the colloid mill, the mixture is sheared and emulsified with the paraffin nanoemulsion for 2-3 hours. The fluid in the colloid mill is then removed to obtain an emulsified asphalt plugging and anti-collapse agent based on the paraffin nanoemulsion. The effective content of high-softening-point asphalt in the emulsified asphalt plugging and anti-collapse agent is approximately 45-65%.

[0043] The mass ratio of the paraffin nanoemulsion, the self-made comb-shaped polycarboxylate dispersant and the asphalt powder is 3.3:0.36:2.

[0044] Compared with the prior art, the present invention has the following advantages:

[0045] On the one hand, the emulsified asphalt plugging and anti-collapse agent described in the present invention improves the softening point of the asphalt component in the emulsified asphalt, and the preparation process is simple, so that it can be further widely used in high-temperature deep wells; on the other hand, the high-temperature resistant and high-softening point emulsified asphalt described in the present invention has a finer particle size, so that it can be further used in high-temperature deep well fractured formations, and its plugging and anti-collapse effect is better than that of existing products. At the same time, the high-temperature resistant and high-softening point emulsified asphalt described in the present invention has both good inhibitory and lubricating effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention.

[0047] Figure 1 This is a transmission electron microscope picture of the emulsified asphalt plugging and anti-collapse agent described in the present invention.

[0048] from Figure 1 It can be seen that the emulsified asphalt plugging and anti-collapse agent described in the present invention is dispersed in the form of spherical particles in water (the black shadow part is asphalt), has good dispersibility in aqueous solution, and the particle size of the spherical particles is about 5-25 μm.

[0049] Figure 2 and Figure 3 It is the particle size distribution curve of the emulsified asphalt plugging and anti-collapse agent described in the present invention.

[0050] From Figure 2 and Figure 3 It can be seen that the median particle size of the emulsified asphalt plugging and anti-collapse agent described in the present invention is about 5-25 μm. DETAILED DESCRIPTION

[0051] The following describes the implementation methods of the present application through specific examples. Those skilled in the art should realize that these specific examples are only to illustrate the specific implementation plans selected to achieve the purpose of the present application, and are not limitations on the technical solutions of the present application.

[0052] Basic Example 1 Preparation Method of Self-made Comb-type Polycarboxylate Dispersant

[0053] The steps include:

[0054] 8.24 g of sodium p-styrene sulfonate, 56 g of allyl alcohol polyoxyethylene ether APEG600 and 3.22 g of methacryloyloxyethyltrimethylammonium chloride were weighed separately, and then 225 mL of deionized water was added to prepare a deionized water solution; the deionized water solution was poured into a 500 mL three-necked flask and stirred at high speed for 20 minutes to dissolve it. Then 2.698 g of ammonium persulfate was added to the reactor, stirred and heated to 45°C. After deoxygenation by N2 for 30 minutes, the temperature was raised to 80°C and the reaction was carried out for 4 hours to obtain a brown thin colloid. After separation and purification, and after removing water in a vacuum at 90°C, a comb-type polycarboxylate strong dispersant was obtained.

[0055] Basic Example 2 Preparation Method of n-octane Nanoemulsion

[0056] The steps include:

[0057] (1) At 55° C., 94 g of GTN cationic gemini surfactant and 106 g of Tween 80 as the main surfactant and 51 g of n-butanol as the co-surfactant were mixed as a surfactant component and cooled for later use;

[0058] (2) 108 g of n-octane was used as the oil phase, and 251 g was added to the surfactant component to form a mixed solution; NaCl solution was used as the aqueous phase, and at an emulsification temperature of 25 ° C and an agent-oil ratio Ros = 7:3, NaCl solution was added dropwise into the mixed solution to obtain an O / W type n-octane nanoemulsion.

[0059] Basic Example 3 Preparation Method of Paraffin Nanoemulsion

[0060] The steps include:

[0061] 150 mL of liquid paraffin, 75 g of Span 80, 75 g of Tween 80 and 45 g of n-butanol were mixed with 150 mL of water, and then 7.5 g of cationic gemini surfactant GTN was added and stirred evenly to form a paraffin nanoemulsion.

[0062] Example 1: An emulsified asphalt plugging and anti-collapse agent and its preparation method

[0063] The emulsified asphalt plugging and anti-collapse agent is obtained by emulsifying asphalt powder, n-octane nanoemulsion and a self-made comb-type polycarboxylate dispersant through a colloid mill under high temperature conditions.

[0064] The specific preparation method is:

[0065] Take 400mL of n-octane nanoemulsion and heat it to 65°C; start the colloid mill with a shear rate of 6000r / min. After the surface temperature of the colloid mill rises, pour the heated n-octane nanoemulsion into the colloid mill, and add a homemade comb-type polycarboxylate dispersant (the amount added is 30% of the total mass of the liquid), and shear emulsify for 20 minutes; finally, weigh 220g of asphalt powder and add it to the colloid mill. Under the shear action of the colloid mill, it is shear emulsified with the n-octane nanoemulsion. After shear emulsification for 1 hour, pour out the fluid in the colloid mill to obtain an emulsified asphalt plugging and anti-collapse agent based on n-octane nanoemulsion. The effective content of the asphalt component in the obtained product is 55%.

[0066] Example 2: An emulsified asphalt plugging and anti-collapse agent and its preparation method

[0067] The emulsified asphalt plugging and anti-collapse agent is obtained by emulsifying asphalt powder, paraffin nanoemulsion and a self-made comb-type polycarboxylate dispersant through a colloid mill under high temperature conditions.

[0068] The specific preparation method is:

[0069] Take 300mL of paraffin nanoemulsion, heat it to 65°C, start the colloid mill, the shear rate of the colloid mill is 6000r / min, after the surface temperature of the colloid mill rises, pour the heated paraffin nanoemulsion into the colloid mill, then add a homemade comb-type polycarboxylate dispersant (the amount added is 30% of the total mass of the liquid), and shear emulsify for 20 minutes; finally, weigh 180g of asphalt powder, pour it into the colloid mill, and under the shear action of the colloid mill, shear emulsify it with the paraffin nanoemulsion. After shear emulsification for 1 hour, pour out the fluid in the colloid mill to obtain an emulsified asphalt plugging and anti-collapse agent based on paraffin nanoemulsion. The effective content of the asphalt component in the obtained product is about 60%.

[0070] Effect experiment-drilling fluid and completion fluid performance evaluation

[0071] Test methods: ①GB / T 18907-2013 Microbeam analysis - Electron microscopy, transmission electron microscopy, selected area electron diffraction analysis method; ②GB / T 5005-2010: Drilling fluid material specification; ③GB / T 16738-1997: Field test procedure for water-based drilling fluids; ④GB / T 4507-2014 "Determination of the softening point of asphalt - Ring and ball method".

[0072] 1. Test results of softening point of evaporation residue of the emulsified asphalt plugging and anti-collapse agent of the present invention and the emulsified asphalt plugging and anti-collapse agent commonly used on site

[0073] Table 1 Test results of softening point of evaporation residue of samples of the present invention and commonly used emulsified asphalt plugging and anti-collapse agents on site

[0074] Serial number Sample name Softening point (℃) 1 Example 1 135 2 Example 2 148.1 3 On-site emulsified asphalt No. 1 48.2 4 On-site emulsified asphalt No. 2 30.6 5 On-site emulsified asphalt No. 3 42.6

[0075] The test results in Table 1 indicate that the emulsified asphalt plugging and anti-slumping agent described herein differs from on-site emulsified asphalt plugging and anti-slumping agents primarily in that the asphalt raw material used in the present invention utilizes high-softening-point asphalt powder. Consequently, the resulting product's evaporation residue has a relatively high softening point, at 135°C and 148.1°C, respectively. Therefore, the high-temperature-resistant, high-softening-point emulsified asphalt plugging and anti-slumping agent described herein can be used at formation temperatures between 130°C and 150°C, effectively demonstrating the emulsified asphalt's plugging and anti-slumping effectiveness even under high-temperature conditions.

[0076] 2. Test on the influence of base slurry rheological properties and filtration loss properties

[0077] Preparation of base slurry: Add 16g of secondary bentonite for drilling fluid and 0.8g of sodium carbonate to 400mL of tap water respectively, stir at a high speed of 8000 rpm for 30 minutes, scrape the material on the wall of the slurry cup into the slurry, continue high-speed stirring for 2 hours, take out and let it stand for 24 hours to obtain the pre-hydrated test base slurry.

[0078] Preparation and Testing of Test Slurries: 4% of the emulsified asphalt plugging and anti-slumping agent described in the present invention and its preparation method evaluation samples (Example 1 and Example 2) and various emulsified asphalt plugging and anti-slumping agents commonly used at drilling sites were added to the prehydrated base slurry. The mixture was stirred at 8000 rpm and the rheological properties and API fluid loss of each test slurry were tested. Each test slurry was placed in a high-temperature aging tank and hot-rolled for 16 hours at 150°C. The rheological properties and API fluid loss of each test slurry were tested using the same method.

[0079] Table 2 Effects of the samples of the present invention and the emulsified asphalt samples currently used on the site on the rheological properties and filtration properties of the bentonite-based slurry

[0080]

[0081] According to the test results in Table 2 above, it can be seen that the high-temperature resistant and high-softening-point emulsified asphalt plugging and anti-collapse agent described in the present invention can significantly reduce the API fluid loss of the bentonite-based slurry. After adding the samples of Example 1 and Example 2 to the base slurry, the fluid loss of the bentonite-based slurry after high-temperature aging was reduced by 36.8% and 47%, respectively. The fluid loss reduction performance is significantly better than the emulsified asphalt plugging and anti-collapse agent currently on site.

[0082] 3. Test on the impact of on-site drilling fluid inhibition performance

[0083] Preparation and testing of test slurries: 5 portions of 400 mL of on-site drilling fluid from the SH-X well were taken. After each test slurry was stirred at high speed for 20 minutes, 20 g of on-site emulsified asphalt No. 1, on-site emulsified asphalt No. 2, on-site emulsified asphalt No. 3, Example 1, and Example 2 were added to each test slurry respectively. After high-speed stirring and uniform mixing, each test slurry was aged at 150°C for 16 hours. The linear expansion rate of each test slurry to inhibit hydration expansion of mudstone was tested using the new JHTP intelligent shale dilatometer.

[0084] Table 3 Effects of the samples of the present invention and the emulsified asphalt samples currently used on site on the inhibition performance of the drilling fluid on site

[0085]

[0086]

[0087] The test results in Table 3 show that the asphalt anti-slump agent described in the present invention can significantly improve the inhibitory properties of on-site drilling fluids. The linear expansion rate of the shale sample used in the experiment in clear water over 8 hours was 14.25%, indicating that the rock sample has strong hydration expansion properties. Its linear expansion rate in the on-site drilling fluid over 8 hours was 5.30%, a 62.8% reduction compared to the linear expansion rate in clear water. After adding the samples from Example 1 and Example 2, the linear expansion rates of the shale sample in the drilling fluid over 8 hours were reduced to 3.86% and 2.89%, respectively, which are 72.9% and 79.7% reductions compared to the linear expansion rates in clear water. These results demonstrate that the high-temperature-resistant, high-softening-point emulsified asphalt plugging and anti-slump agent described in the present invention significantly improves the inhibitory properties of on-site drilling fluids.

[0088] 4. Test on the influence of on-site drilling fluid lubrication performance

[0089] Preparation and testing of test slurries: 5 portions of SH-X well on-site drilling fluid, 400 mL each, were taken. After each test slurry was stirred at high speed for 20 minutes, 20 g of on-site emulsified asphalt No. 1, on-site emulsified asphalt No. 2, on-site emulsified asphalt No. 3, Example 1, and Example 2 were added to each test slurry respectively. After high-speed stirring and uniform mixing, each test slurry was subjected to high-temperature aging at 150°C for 16 hours. The lubrication coefficient and mud cake viscosity coefficient of each test slurry were tested using an EP-2 extreme pressure lubrication instrument and a mud cake viscosity coefficient tester.

[0090] Table 4 Effects of the samples of the present invention and the emulsified asphalt samples currently used on site on the lubrication properties of the drilling fluid

[0091]

[0092]

[0093] The test results in Table 4 demonstrate that the emulsified asphalt plugging and anti-slumping agent described herein significantly improves the lubricity of in-situ drilling fluids. After adding the samples from Example 1 and Example 2 to the in-situ drilling fluids, the lubricity coefficient of the experimental slurries significantly decreased compared to the in-situ drilling fluids, with reductions of 41.18% to 45.28%, respectively. Compared to the in-situ emulsified asphalt plugging and anti-slumping agent, the high-temperature-resistant, high-softening-point emulsified asphalt plugging and anti-slumping agent described herein exhibits superior lubricity improvements.

[0094] 5. Test on the impact of on-site drilling fluid plugging and anti-collapse performance

[0095] Preparation and testing of test slurry: Take 5 portions of SH-X well on-site drilling fluid, each 400 mL, and stir each test slurry at high speed for 20 minutes. Then, add 20 g of on-site emulsified asphalt No. 1, on-site emulsified asphalt No. 2, on-site emulsified asphalt No. 3, Example 1 and Example 2 to each test slurry respectively. After high-speed stirring and uniformity, each test slurry is aged at 150°C for 16 hours, and then the PPA sand disk plugging performance of each test slurry is tested using a permeability plugging instrument (PPA sand disk model selection 210538, permeability 10 μm2).

[0096] Table 5 Effects of the samples of the embodiments of the present invention and the emulsified asphalt samples currently used on site on the plugging and anti-collapse performance of the drilling fluid on site

[0097]

[0098] The test data in Table 5 above demonstrate that the emulsified asphalt plugging and anti-collapse agent described herein can significantly reduce on-site drilling fluid loss. The PPA loss of the on-site drilling fluid was 18 mL. After adding the samples from Example 1 and Example 2 to the on-site drilling fluid, the PPA loss was reduced to 9.6 mL and 6.8 mL, respectively, representing reductions of approximately 46.7% and 62.2% relative to the on-site drilling fluid PPA loss. Furthermore, the addition of the samples from Example 1 and Example 2 to the on-site drilling fluid also significantly reduced the instantaneous fluid loss and static fluid loss rate of the on-site drilling fluid.

[0099] Based on the test results in Tables 3 to 5, the emulsified asphalt plugging and anti-slumping agent described herein exhibits excellent fluid loss reduction, inhibition, lubrication, and plugging and anti-slumping properties for water-based drilling fluids. Compared to on-site emulsified asphalt, its adaptability and functional effectiveness in high-temperature formation conditions are even more outstanding. The high-temperature-resistant, high-softening-point emulsified asphalt plugging and anti-slumping agent described herein primarily increases the softening point of the asphalt component in the emulsified asphalt. Unlike conventional methods for preparing emulsified asphalt plugging and anti-slumping agents for drilling fluids, the method described herein provides a novel technical solution for the preparation of high-softening-point emulsified asphalt.

Claims

1. An emulsified asphalt plugging and anti-collapse agent, characterized by: The emulsified asphalt plugging and anti-collapse agent is obtained by emulsifying asphalt powder, nanoemulsion and dispersant through a colloid mill under high temperature conditions; The mass ratio of the asphalt powder, nanoemulsion and dispersant is 3-4:1.8-2.2:0.25-0.35; The high temperature is 60-70°C; The nanoemulsion is n-octane nanoemulsion or paraffin nanoemulsion; The preparation method of the dispersant comprises the following steps: Sodium p-styrene sulfonate, allyl alcohol polyoxyethylene ether APEG600 and methacryloyloxyethyl trimethylammonium chloride were weighed separately, prepared into a deionized water solution, poured into a 250 mL three-necked flask, stirred at high speed to dissolve, and then added ammonium persulfate to the reactor. Deionized water was added to control the total monomer concentration to 30-35%. Stir and heat to 35-45 ° C. After deoxygenation with N2 for 30 minutes, the temperature was raised to 70-80 ° C. and reacted for 4-6 hours to obtain a brown thin colloid. After separation and purification, the water was removed in a vacuum at 90 ° C to obtain a dispersant.

2. The emulsified asphalt plugging and anti-collapse agent according to claim 1, characterized in that: The distribution range of the median particle size D50 of the asphalt powder is 2-40 μm, and the softening point temperature is 130-150° C.

3. The emulsified asphalt plugging and anti-collapse agent according to claim 1, characterized in that: The preparation method of the n-octane nanoemulsion comprises the following steps: (1) GTN cationic gemini surfactant and Tween 80 as main surfactants and n-butanol as co-surfactant are mixed at 55-60° C. to obtain a surfactant component, which is then cooled for later use; (2) using n-octane as the oil phase and adding it to the surfactant component to form a mixed solution; With NaCl solution as the water phase, under the conditions of emulsification temperature of 25° C. and agent-oil ratio Ros=6.5-7.5:2.8-3.2, NaCl solution is added dropwise into the mixed solution to obtain O / W type n-octane nanoemulsion.

4. The emulsified asphalt plugging and anti-collapse agent according to claim 3, characterized in that: The mass ratio of the GTN cationic gemini surfactant, Tween 80 and n-butanol described in step (1) is 45.5-52.5:47.5-54.5:20-30.

5. The emulsified asphalt plugging and anti-collapse agent according to claim 3, characterized in that: The mass ratio of the GTN cationic gemini surfactant, Tween 80 and n-butanol described in step (1) is 47:53:25.

5.

6. The emulsified asphalt plugging and anti-collapse agent according to claim 3, characterized in that: The mass ratio of n-octane to the surfactant component in step (2) is 15-20:35-5.

7. The emulsified asphalt plugging and anti-collapse agent according to claim 6, characterized in that: The mass ratio of n-octane to the surfactant component in step (2) is 16.8:39.

1.

8. The emulsified asphalt plugging and anti-collapse agent according to claim 1, characterized in that: The preparation method of the paraffin nanoemulsion comprises the following steps: Liquid paraffin, Span 80, Tween 80 and n-butanol were weighed and mixed with water, and then cationic gemini surfactant GTN was added and stirred evenly to form a paraffin nanoemulsion.

9. The emulsified asphalt plugging and anti-collapse agent according to claim 8, characterized in that: The mass of the liquid paraffin is the same as the total amount of Span 80 and Tween 80; the mass ratio of Span 80 to Tween 80 is 1:1; and the mass ratio of n-butanol to liquid paraffin is 0.25-0.35:

1.

10. The emulsified asphalt plugging and anti-collapse agent according to claim 8, characterized in that: The volume ratio of the total mass of the liquid paraffin, Span 80, Tween 80 and n-butanol to water is 20-25:8.5-13.5 (g / mL).

11. The emulsified asphalt plugging and anti-collapse agent according to claim 10, characterized in that: The volume ratio of the total mass of the liquid paraffin, Span 80, Tween 80 and n-butanol to water is 23:10 (g / mL).

12. The emulsified asphalt plugging and anti-collapse agent according to claim 8, characterized in that: The added amount of the cationic gemini surfactant GTN is 1.5% of the total mass.

13. The emulsified asphalt plugging and anti-collapse agent according to claim 1, characterized in that: The mass ratio of the sodium styrene sulfonate, allyl alcohol polyoxyethylene ether APEG600 and methacryloyloxyethyl trimethylammonium chloride is 0.35-0.55:0.8-1.2:0.05-0.

35.

14. The emulsified asphalt plugging and anti-collapse agent according to claim 13, characterized in that: The mass ratio of the sodium styrene sulfonate, allyl alcohol polyoxyethylene ether APEG600 and methacryloyloxyethyl trimethylammonium chloride is 0.45:0.9:0.

15.

15. The emulsified asphalt plugging and anti-collapse agent according to claim 1, characterized in that: The volume ratio of the total mass of the sodium styrene sulfonate, allyl alcohol polyoxyethylene ether APEG600 and methacryloyloxyethyl trimethylammonium chloride to deionized water is 30:100 (g / mL).

16. The emulsified asphalt plugging and anti-collapse agent according to claim 1, characterized in that: The ratio of the added amount of ammonium persulfate to the total mass of sodium styrene sulfonate, allyl alcohol polyoxyethylene ether APEG600 and methacryloyloxyethyl trimethylammonium chloride is 0.05-5:

100.

17. A method for preparing the emulsified asphalt plugging and anti-collapse agent according to any one of claims 1 to 7 and 12 to 16, characterized in that: Take n-octane nanoemulsion, heat it to 60-70°C, start a colloid mill, pour the heated n-octane nanoemulsion into the colloid mill, add a homemade comb-type polycarboxylate dispersant, and pre-shear emulsification for 10-15 minutes; then pour asphalt powder into the colloid mill, and shear emulsify it with the n-octane nanoemulsion under the shear action of the colloid mill for 2-3 hours. Remove the fluid from the colloid mill to obtain an emulsified asphalt plugging and anti-collapse agent based on n-octane nanoemulsion; the effective content of high softening point asphalt in the emulsified asphalt plugging and anti-collapse agent is 45-65%; The mass ratio of the n-octane nanoemulsion, the homemade comb-type polycarboxylate dispersant and the asphalt powder is 4:0.36:2.

2.

18. A method for preparing the emulsified asphalt plugging and anti-collapse agent according to any one of claims 1 to 3 and 8 to 16, characterized in that: A paraffin nanoemulsion is heated in a water bath to 60-70°C, and a colloid mill is started. The heated paraffin nanoemulsion is poured into the colloid mill, and a homemade comb-type polycarboxylate dispersant is added. The mixture is sheared and emulsified for 10-15 minutes. Asphalt powder is then weighed and poured into the colloid mill. Under the shear action of the colloid mill, the mixture is sheared and emulsified with the paraffin nanoemulsion for 2-3 hours. The fluid in the colloid mill is then removed to obtain an emulsified asphalt plugging and anti-collapse agent based on the paraffin nanoemulsion. The effective content of high softening point asphalt in the emulsified asphalt plugging and anti-collapse agent is 45-65%. The mass ratio of the paraffin nanoemulsion, the self-made comb-shaped polycarboxylate dispersant and the asphalt powder is 3.3:0.36:2.

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