Silicon oxide-oil phase shell-core structure dispersion liquid, composite pressure-displacing agent and preparation of composite pressure-displacing agent
The composite pressure-displacement agent composed of silica-oil phase core-shell structure dispersion and microemulsion has solved the problems of short effective period and low recovery rate of pressure-displacement agents in low-permeability tight oil reservoirs, achieved the improvement of micro-fracture throughput and spontaneous imbibition effect, and increased the recovery rate.
Patent Information
- Application Number
- CN202410341079.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-25
- Publication Date
- 2025-09-26
AI Technical Summary
Existing pressure-displacement agents have a short effective period, small impact range, and high cost in low-permeability tight oil reservoirs. In addition, the recovery rate of low-permeability/ultra-low-permeability reservoirs is low, and it is difficult to form a durable fracture network through hydraulic fracturing.
A composite pressure-displacement agent consisting of a silica-oil phase core-shell dispersion and a microemulsion is used to enter low-permeability/ultra-low-permeability reservoirs using micro-fracture huff-and-puff technology. Microcracks are formed by breaking the silica shell, and the spontaneous imbibition effect is enhanced through the synergistic effect of the oil phase and the microemulsion.
It significantly improves the recovery rate of low permeability/ultra-low permeability oil reservoirs, has simple process, good formation injectivity, significant cost-effectiveness and good market prospects.
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Figure BDA0004756834570000101
Abstract
Description
Technical Field
[0001] The invention relates to a silicon oxide-oil phase core-shell structure dispersion, a composite pressure-displacing agent and preparation thereof. Background Art
[0002] Low-permeability, tight, and shale oil reservoirs are abundant and have enormous development potential. Their share of newly discovered proven oil reserves is gradually increasing. However, unused crude oil in these reservoirs is primarily located in blocks with permeabilities below 1 mD. These reservoirs exhibit poor physical properties, low porosity and permeability, and are characterized by naturally occurring microfractures, small microscopic pore throats, and complex pore structures. Waterflooding of these low-permeability reservoirs presents challenges, resulting in low recovery rates and a lack of injection and consequently, low recovery rates. Hydraulic fracturing, acidizing, and augmented injection have been used to address this problem, improving the development of these reservoirs. Tight shale reservoirs are typically developed using volumetric fracturing to create a fracture network and generate industrial oil flow. However, this process results in high production decline rates, rapid energy depletion, and low primary recovery rates. However, the fracturing effect is short-lived, and existing pressure-displacement agent systems generally suffer from a short shelf life, limited reach, and high cost in low-permeability, tight reservoirs. Summary of the Invention
[0003] In order to at least partially solve the above-mentioned technical problems existing in the prior art, an embodiment of the present invention provides a composite pressure-displacement agent and a preparation method, which, on the one hand, can improve the fracture-making effect of micro-fracture throughput; on the other hand, it can improve the spontaneous imbibition effect during the well blocking process, thereby significantly improving the recovery rate of low permeability / ultra-low permeability and tight shale oil reservoirs.
[0004] As a first aspect of the present invention, a silicon oxide-oil phase core-shell structure dispersion is provided.
[0005] The dispersion is based on an alkyl glycoside surfactant.
[0006] In one or some possible embodiments, the dispersion comprises the following constituent materials, calculated by mass percentage: 0.5% to 1% of a quaternary ammonium surfactant, 3% to 7% of a normal alkane, 40% to 60% of ethanol, 3% to 6% of aqueous ammonia, 3% to 5% of a silane coupling agent, 0.1% to 0.5% of a block copolymer, and the remainder being deionized water.
[0007] In one or some possible embodiments, the quaternary ammonium salt surfactant is betaine and / or a betaine derivative.
[0008] In one or some possible embodiments, the normal alkane is selected from C4 to C8 normal alkanes;
[0009] Preferably, the n-alkane is selected from one or more of n-hexane, n-butane or n-pentane.
[0010] In one or some possible embodiments, the silane coupling agent is selected from one of vinyltrichlorosilane, vinyltriethoxysilane, vinyltriacetoxysilane or ethyl orthosilicate.
[0011] In one or some possible embodiments, the block copolymer is a styrene-butadiene-3-chloropropylene copolymer and / or a styrene-butadiene copolymer.
[0012] As a second aspect of the present invention, a method for preparing the above-mentioned silica-oil phase core-shell structure dispersion comprises the following steps:
[0013] S1. Dissolve a quaternary ammonium surfactant in a portion of deionized water according to the formula to obtain a surfactant aqueous solution, then add n-alkane, stir the oil-water system at 60°C for 3-6 hours, and ultrasonically emulsify for 30-60 minutes to obtain a uniform turbid milky white suspension, thereby forming intermediate product 1;
[0014] S2. According to the formula, ethanol, ammonia water and the remaining deionized water were mixed at 60° C. for 60 minutes under stirring. A silane coupling agent was added dropwise to the mixture. The mixture was stirred and reacted at room temperature for 30 minutes to form an intermediate product 2.
[0015] S3. At 60°C, add intermediate product 2 dropwise to intermediate product 1 while stirring, add block copolymer to the mixture, maintain the constant temperature for 24 hours, increase the temperature to 100°C, and maintain for 24 hours to obtain an oil-phase microsphere dispersion with a siliceous shell based on an emulsion template.
[0016] As a third aspect of the present invention, it relates to the use of the above-mentioned silicon oxide-oil phase core-shell structure dispersion in the preparation of a pressure-displacing agent.
[0017] As a fourth aspect of the present invention, a composite pressure-displacing agent is provided, wherein the pressure-displacing agent comprises the above-mentioned silicon oxide-oil phase core-shell structure dispersion.
[0018] In one or some possible embodiments, the pressure-displacing agent further comprises a microemulsion.
[0019] In one or some possible embodiments, the microemulsion comprises the following constituent materials, calculated by mass percentage: 20% to 25% fatty alcohol polyoxyethylene ether, 15% to 18% hydroxy ether, 10% to 13% zwitterionic surfactant, 18% to 20% auxiliary agent, and the balance is deionized water.
[0020] In one or some possible embodiments, the fatty alcohol polyoxyethylene ether is selected from one or more of AEO9, AEO12, and AEO15.
[0021] In one or some possible embodiments, the hydroxy ether is propylene glycol butyl ether and / or ethylene glycol butyl ether.
[0022] In one or some possible embodiments, the zwitterionic surfactant is selected from one or more of an amino acid surfactant, a carboxylic acid betaine, a sulfobetaine, a phosphate betaine or an imidazole surfactant.
[0023] In one or some possible embodiments, the auxiliary agent is selected from one or more of kerosene, n-hexane or industrial white oil.
[0024] In one or some possible embodiments, the pressure-displacing agent comprises the following raw materials by mass percentage: 0.3% to 0.7% of silicon oxide-oil phase core-shell structure dispersion, 0.1% to 1.7% of microemulsion, and the balance of deionized water.
[0025] As a fifth aspect of the present invention, it relates to a method for preparing the above-mentioned composite pressure-displacing agent, which comprises mixing the above-mentioned constituent raw materials according to the formula of the composite pressure-displacing agent to obtain the composite pressure-displacing agent.
[0026] In one or some possible embodiments, the preparation of the microemulsion comprises the following steps:
[0027] The fatty alcohol polyoxyethylene ether, hydroxy ether and zwitterionic surfactant were stirred for 30 minutes and mixed to obtain an intermediate product 1;
[0028] Adding an auxiliary agent dropwise to the intermediate product 1 to obtain an intermediate product 2;
[0029] Deionized water was added dropwise to the intermediate product 2, stirred until dissolved, and mixed to obtain a microemulsion concentrate.
[0030] The composite pressure-displacement agent prepared by the present invention can enter low-permeability / ultra-low-permeability and tight shale oil reservoirs by utilizing micro-fracture throughput technology. When encountering micro-cracks during migration, the oil phase can be released by rupturing the siliceous shell. On the one hand, the ruptured siliceous shell can improve the fracture-forming effect of the micro-fracture throughput. On the other hand, the released oil phase and the oil core of the microemulsion synergistically increase oil production, thereby improving the spontaneous imbibition effect of the well soaking process, thereby significantly improving the recovery rate of low-permeability / ultra-low-permeability and tight shale oil reservoirs.
[0031] The composite pressure-displacement agent of the present invention does not contain macromolecules (referring to hydrocarbons with a carbon number greater than 8), has good formation injectability, can effectively solve the problem of low recovery rate of low permeability / ultra-low permeability and tight shale oil reservoirs, and can be used for high-efficiency throughput and well shut-in and imbibition work in low permeability / ultra-low permeability and tight shale oil reservoirs. When the composite pressure-displacement agent of the present invention is used on site, the process is simple and it has good market prospects. DETAILED DESCRIPTION
[0032] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.
[0033] In the description of the present invention, it should be noted that the terms “include”, “including”, “have”, “contain”, etc. are all open terms, which mean including but not limited to.
[0034] The present invention will be further described below with reference to specific examples, but the scope of protection of the present invention is not limited by the following examples. Unless otherwise specified, the sources of materials mainly involved in the examples are conventional commercial products.
[0035] Example 1
[0036] The composite pressure displacement agent of this embodiment includes the following raw materials in percentage by mass: 0.3% of silicon oxide-oil phase core-shell structure dispersion; 0.2% of microemulsion; and the remainder of deionized water;
[0037] The preparation method of the silica-oil phase core-shell structure dispersion is as follows:
[0038] S1. Dissolve 2 g of betaine (quaternary ammonium surfactant) in deionized water to obtain a surfactant aqueous solution, then add 10 g of n-hexane (normal alkane), stir the oil-water system at 60° C. for 3 h, and ultrasonically emulsify for 30 min to obtain a uniform turbid milky white suspension, forming intermediate product 1;
[0039] S2. Stir 50 mL of ethanol, 3 mL of deionized water, and 3 mL of aqueous ammonia at 60°C for 60 min, add 2 mL of ethyl orthosilicate dropwise, and stir while maintaining at room temperature for 30 min to form intermediate 2.
[0040] S3. At 60°C, add intermediate product 2 dropwise to intermediate product 1 while stirring. After uniform mixing, add 0.2g of styrene-butadiene-3-chloropropylene copolymer (block copolymer). Keep at 60°C for 24h, increase the temperature, and maintain at 100°C for 24h to obtain a silica-oil phase core-shell structure dispersion.
[0041] The preparation method of microemulsion is as follows:
[0042] 22g of AEO9 (fatty alcohol polyoxyethylene ether), 16g of propylene glycol butyl ether (hydroxy ether) and 12g of carboxylic acid betaine (zwitterionic surfactant) were stirred for 30min and mixed to obtain intermediate product 1;
[0043] 20 g of n-hexane was added dropwise to intermediate product 1 to obtain intermediate product 2;
[0044] Deionized water was added dropwise to the intermediate product 2 and stirred until dissolved to form a microemulsion.
[0045] Example 2
[0046] The composite pressure displacement agent of this embodiment includes the following raw materials in percentage by mass: 0.5% of silicon oxide-oil phase core-shell structure dispersion, 0.4% of microemulsion, and the remainder of deionized water.
[0047] The preparation method of the silica-oil phase core-shell structure dispersion is as follows:
[0048] S1. Dissolve 3 g of carboxylic acid betaine (quaternary ammonium surfactant) in 60 mL of deionized water to obtain a surfactant aqueous solution, then add 15 g of n-pentane (normal alkane), stir the oil-water system at 60° C. for 5 h, and ultrasonically emulsify for 45 min to obtain a uniform turbid milky white suspension, forming intermediate product 1;
[0049] S2. Stir 60 mL of ethanol, 4 mL of deionized water, and 4 mL of aqueous ammonia at 60°C for 60 min, add 2.5 mL of vinyltrichlorosilane dropwise, and stir while maintaining at room temperature for 30 min to form intermediate 2;
[0050] S3. At 60°C, add intermediate product 2 dropwise to intermediate product 1 while stirring, then add 0.3g of styrene-butadiene copolymer, mix well, maintain at 60°C for 24h, increase the temperature, and maintain at 100°C for 24h to obtain a silica-oil phase core-shell structure dispersion.
[0051] The preparation method of microemulsion is as follows:
[0052] 20 g of fatty alcohol polyoxyethylene ether AEO12, 15 g of propylene glycol butyl ether and 10 g of sulfobetaine were stirred for 30 min and mixed evenly to obtain intermediate product 1;
[0053] 18 g of industrial white oil was added dropwise to intermediate product 1 to obtain intermediate product 2;
[0054] Deionized water was added dropwise to the intermediate product 2 and stirred until dissolved to form a microemulsion.
[0055] Example 3
[0056] The composite pressure displacement agent of this embodiment includes the following raw materials in percentage by mass: 0.7% of silicon oxide-oil phase core-shell structure dispersion, 0.7% of microemulsion, and the remainder of deionized water.
[0057] The preparation method of the silica-oil phase core-shell structure dispersion is as follows:
[0058] S1. Dissolve 5 g of sulfobetaine in 70 mL of deionized water to obtain a surfactant aqueous solution, then add 20 g of n-pentane, stir the oil-water system at 60° C. for 6 h, and ultrasonically emulsify for 60 min to obtain a uniform turbid milky white suspension, forming intermediate product 1;
[0059] S2. Stir 70 mL of ethanol, 6 mL of deionized water, and 6 mL of aqueous ammonia at 60°C for 60 min, add 3 mL of ethyl orthosilicate dropwise, and react at room temperature while stirring for 30 min to form intermediate 2.
[0060] S3. At 60°C, add intermediate product 2 dropwise to intermediate product 1 while stirring, then add 0.4 g of styrene-butadiene copolymer, mix well, maintain at 60°C for 24 hours, increase the temperature, and maintain at 100°C for 24 hours to obtain a silica-oil phase core-shell structure dispersion.
[0061] The microemulsion preparation method is as follows:
[0062] 25 g of fatty alcohol polyoxyethylene ether AEO15, 18 g of ethylene glycol butyl ether and 13 g of phosphate betaine were stirred for 30 min and mixed uniformly to obtain intermediate product 1;
[0063] 20 g of n-hexane was added dropwise to intermediate product 1 to obtain intermediate product 2;
[0064] Deionized water was added dropwise to the intermediate product 2 and stirred until dissolved to form a microemulsion.
[0065] Comparative Example 1
[0066] The composite pressure-displacing agent of the comparative example includes the following raw materials in percentage by mass: 0.5% of silicon oxide-oil phase core-shell structure dispersion and the rest of deionized water.
[0067] The preparation method of the silica-oil phase core-shell structure dispersion is as follows:
[0068] S1. Dissolve 3 g of carboxylic acid betaine (quaternary ammonium surfactant) in 60 mL of deionized water to obtain a surfactant aqueous solution, then add 15 g of n-pentane (normal alkane), stir the oil-water system at 60° C. for 5 h, and ultrasonically emulsify for 45 min to obtain a uniform turbid milky white suspension, forming intermediate product 1;
[0069] S2. Stir 60 mL of ethanol, 4 mL of deionized water, and 4 mL of aqueous ammonia at 60°C for 60 min, add 2.5 mL of vinyltrichlorosilane dropwise, and stir while maintaining at room temperature for 30 min to form intermediate 2;
[0070] S3. At 60°C, add intermediate product 2 dropwise to intermediate product 1 while stirring, then add 0.3g of styrene-butadiene copolymer, mix well, maintain at 60°C for 24h, increase the temperature, and maintain at 100°C for 24h to obtain a silica-oil phase core-shell structure dispersion.
[0071] The following performance tests were performed on the above Examples 1 to 3 and Comparative Example 1:
[0072] Test-Interfacial Tension Test
[0073] The interfacial tension between a silica-oil-phase core-shell microemulsion composite pressure displacement agent and crude oil was measured using a TX-500 spinning drop interfacial tension meter, referring to GB / T 22237-2008. The silica-oil-phase core-shell microemulsion composite pressure displacement agent and crude oil were injected into a glass capillary tube, which was then placed in the sample cell of the interfacial tension meter. The interfacial tension between the capillary tube and the crude oil was measured at a rotation speed of 6000 r / min and a 1-minute interval.
[0074] Test 2 Wettability test
[0075] With reference to SY / T 5153-2017, the wettability of silica-oil-phase core-shell microemulsion composite pressure displacement agents was determined using a contact angle meter. Quartz slides were aged in silicone oil for seven days. The aged slides were then immersed in different silica-oil-phase core-shell microemulsion composite pressure displacement agents and allowed to stand for three days. The contact angles of the modified slides were then measured. Deionized water was added to the slide using the sessile drop method, and the air-water-solid three-phase contact angles were measured using the three-point method. The average of the three measurements was taken.
[0076] Test three wash oil experiment
[0077] Oil sand was added to the example at a ratio of m(oil sand):m(example)=1:10, and the mixture was oscillated for 24 h at a laboratory reservoir temperature (about 45° C.) with an oscillation frequency of 60 r / min. After the reaction was completed, the mixture was cooled and allowed to stand for 2 h to obtain an eluent, and the oil washing efficiency was calculated.
[0078] Test four imbibition experiments
[0079] The following procedures were followed in accordance with the article "Wang Xibang, Jiang Linhong, Bao Jianyin, et al. Description of the imbibition experiment and evaluation of the method's applicability" (Petrochemical Applications, 2015, 34(12): 102-105). Specifically, the core was dried and weighed, then evacuated to 100% saturation with experimental oil, and the mass of the saturated core was measured. The core was mounted on a core holder and subjected to a natural imbibition experiment. The imbibition process is a self-priming process of water and oil. The experiment was conducted in a constant temperature chamber, using an electronic balance connected to a data acquisition system to continuously weigh the rock sample and record the mass change.
[0080] The performance data results of the above tests 1 to 4 are recorded in Table 1 below.
[0081] Table 1: Performance test results of the composite pressure displacement agent prepared in Examples 1 to 3
[0082]
[0083] As can be seen from Table 1, Examples 1-3 all exhibited superior interfacial tension reduction and wetting reversal effects compared to the comparative example. The oil washing rates of the examples were significantly higher than those of the comparative example. Therefore, Examples 1-3 were able to achieve the highest imbibition recovery rates. Among them, Example 1 exhibited the strongest wetting reversal and interfacial tension reduction capabilities, as well as the highest oil washing rate, thus achieving the highest imbibition effect.
[0084] Although the present invention has been described in considerable detail and with particularity with respect to several embodiments, it is not intended to limit the present invention to any of these details or embodiments or any particular embodiment, so as to effectively encompass the intended scope of the present invention. In addition, the present invention has been described above with respect to embodiments foreseen by the inventors for the purpose of providing a useful description, and those insubstantial modifications of the present invention that are not currently foreseen may still represent equivalent modifications of the present invention.
[0085] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
[0086] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.
Claims
1. A silicon oxide-oil phase core-shell structure dispersion, characterized in that: The dispersion is based on an alkyl glycoside surfactant.
2. The silicon oxide-oil phase core-shell structure dispersion according to claim 1, characterized in that The dispersion comprises the following raw materials by mass percentage: 0.5% to 1% of a quaternary ammonium surfactant, 3% to 7% of normal alkane, 40% to 60% of ethanol, 3% to 6% of aqueous ammonia, 3% to 5% of a silane coupling agent, 0.1% to 0.5% of a block copolymer, and the balance being deionized water.
3. The silicon oxide-oil phase core-shell structure dispersion according to claim 2, characterized in that The quaternary ammonium salt surfactant is betaine and / or a betaine derivative.
4. The silicon oxide-oil phase core-shell structure dispersion according to claim 2, characterized in that The normal alkanes are selected from C4 to C8 normal alkanes; Preferably, the n-alkane is selected from one or more of n-hexane, n-butane or n-pentane.
5. The silicon oxide-oil phase core-shell structure dispersion according to claim 2, characterized in that The silane coupling agent is selected from one of vinyl trichlorosilane, vinyl triethoxysilane, vinyl triacetoxysilane or ethyl orthosilicate.
6. The silicon oxide-oil phase core-shell structure dispersion according to claim 2, characterized in that: The block copolymer is a styrene-butadiene-3-chloropropylene copolymer and / or a styrene-butadiene copolymer.
7. A method for preparing the silicon oxide-oil phase core-shell structure dispersion according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: S1. Dissolve a quaternary ammonium surfactant in a portion of deionized water according to the formula to obtain a surfactant aqueous solution, add n-alkane, stir the oil-water system at 60° C. for 3 to 6 hours, and ultrasonically emulsify for 30 to 60 minutes to obtain a uniform turbid milky white suspension, thereby forming intermediate product 1; S2. According to the formula, ethanol, ammonia water and the remaining deionized water were mixed at 60° C. for 60 minutes under stirring. A silane coupling agent was added dropwise to the mixture. The mixture was stirred and reacted at room temperature for 30 minutes to form an intermediate product 2. S3. At 60°C, add intermediate product 2 dropwise to intermediate product 1 while stirring, add block copolymer to the mixture, maintain the constant temperature for 24 hours, increase the temperature to 100°C, and maintain for 24 hours to obtain an oil-phase microsphere dispersion with a siliceous shell based on an emulsion template.
8. Use of the silicon oxide-oil phase core-shell structure dispersion according to any one of claims 1 to 6 in the preparation of a pressure-displacing agent.
9. A composite pressure-displacing agent, characterized in that: The pressure-displacing agent comprises the silicon oxide-oil phase core-shell structure dispersion according to any one of claims 1 to 6.
10. The composite pressure-displacing agent according to claim 9, characterized in that: The pressure displacement agent further comprises a microemulsion.
11. The composite pressure-displacing agent according to claim 10, characterized in that: The microemulsion comprises the following raw materials by mass percentage: 20% to 25% of fatty alcohol polyoxyethylene ether, 15% to 18% of hydroxy ether, 10% to 13% of zwitterionic surfactant, 18% to 20% of auxiliary agent, and the balance is deionized water.
12. The composite pressure-displacing agent according to claim 11, characterized in that: The fatty alcohol polyoxyethylene ether is selected from one or more of AEO9, AEO12, and AEO15.
13. The composite pressure-displacing agent according to claim 11, characterized in that: The hydroxy ether is propylene glycol butyl ether and / or ethylene glycol butyl ether.
14. The composite pressure-displacing agent according to claim 11, characterized in that: The zwitterionic surfactant is selected from one or more of an amino acid surfactant, a carboxylic acid betaine, a sulfobetaine, a phosphate betaine or an imidazole surfactant.
15. The composite pressure-displacing agent according to claim 11, characterized in that: The auxiliary agent is selected from one or more of kerosene, n-hexane or industrial white oil.
16. The composite pressure-displacing agent according to claim 10, characterized in that: The pressure-displacing agent comprises the following raw materials by mass percentage: 0.3% to 0.7% of silicon oxide-oil phase core-shell structure dispersion, 0.1% to 1.7% of microemulsion, and the balance of deionized water.
17. A method for preparing the composite pressure-displacing agent according to any one of claims 9 to 16, characterized in that: The method comprises mixing the component raw materials according to the formula of the composite pressure-displacing agent to prepare the composite pressure-displacing agent.
18. The method for preparing the composite pressure-displacing agent according to claim 17, characterized in that: The preparation of the microemulsion comprises the following steps: The fatty alcohol polyoxyethylene ether, hydroxy ether and zwitterionic surfactant were stirred for 30 minutes and mixed to obtain an intermediate product 1; Adding an auxiliary agent dropwise to the intermediate product 1 to obtain an intermediate product 2; Deionized water was added dropwise to the intermediate product 2, stirred until dissolved, and mixed to obtain a microemulsion concentrate.