Slow-dissolving temporary plugging particles for pressure driving and preparation method thereof, anti-channeling temporary plugging system and application

Abstract

The invention discloses slow-dissolving temporary plugging particles for pressure driving. The slow-dissolving temporary plugging particles are composed of hollow soluble metal alloy particles and hydrophobic layers wrapping the outer sides of the hollow soluble metal alloy particles. The preparation method comprises the following steps: (1) putting 80 parts of hollow soluble metal alloy particles into a reaction container, then adding 2-10 parts of a coupling agent into the reaction container, oscillating, then adding 2-8 parts of a network architecture agent, and oscillating again to obtain a first fluid; and (2) adding 0.5-5 parts of a catalyst into the first fluid, shaking and uniformly mixing to obtain a second fluid, pouring out the second fluid, flatly laying the second fluid in a container, and irradiating the second fluid with an ultraviolet lamp to obtain the slow-dissolving temporary plugging particles for pressure driving. The invention also discloses an anti-channeling temporary plugging system, which is composed of the following components: 5-20% of pressure-driving slow-dissolving temporary plugging particles, 0.5-5% of a nonionic surfactant, and the balance of water.

Description

Technical Field

[0001] This invention relates to the fields of oilfield chemistry and oil and gas field development engineering technology, and in particular to a slow-dissolving temporary plugging particle for pressure drive, its preparation method, anti-channeling temporary plugging system and its application. Background Technology

[0002] Low-permeability oilfields refer to oilfields with low reservoir permeability, low abundance, and low single-well productivity. Low-permeability oil and gas fields are of great significance to my country's oil and gas development. my country's low-permeability oil and gas resources are characterized by abundant oil and gas content, diverse reservoir types, wide distribution areas, and a pattern of "gas above oil, marine gas as the main component, and continental oil and gas as well." Low-permeability oil reservoirs account for a very high proportion of the proven reserves, approximately two-thirds of the national total, indicating enormous development potential.

[0003] Low-permeability oilfields are primarily developed using water-drive. However, due to the complex reservoir conditions, development of low-permeability reservoirs is challenging. During water injection development in low-permeability reservoirs, common problems include high injection pressure and a high under-injection ratio, resulting in a prominent contradiction of "injection failure and production failure." Effective displacement between oil and water wells cannot be established, formation energy declines rapidly, and production capacity decreases quickly, sometimes even leading to shutdown.

[0004] Hydraulic fracturing and water injection is an effective development technology for low-permeability reservoirs. It aims to force the low-permeability reservoir to absorb a large amount of water through ultra-high pressure injection, rapidly increasing pressure and energy. After well shut-in, the pressure is transmitted and balanced, driving crude oil to migrate to the production well. Ultimately, this allows the well to release pressure, increase fluid volume, and boost production during well opening, thereby significantly improving reservoir recovery. Hydraulic fracturing and water injection combines hydraulic fracturing with water injection, enabling rapid and effective replenishment of formation energy and potentially solving the aforementioned problems.

[0005] However, the following problems exist in the process of pressure-driven water injection development: (1) It is difficult to turn the fractures, the lateral micro-fractures are poorly opened, the fractures are single, the pressure-driven sweep coefficient is low, resulting in low oil displacement efficiency; (2) The main fractures are prone to excessive extension, resulting in pressure penetration, causing oil and water wells to penetrate, water to flow too early, and causing oil wells to stop production.

[0006] To address the aforementioned issues, there is an urgent need to develop a temporary plugging system to prevent excessive extension of the main fracture during pressure-driven water injection, which could lead to fracture isolation or water channeling; at the same time, it should not completely block the fracture so that water injection can continue after pressure-driven water injection is completed.

[0007] Currently, there are various types of temporary plugging agents. Based on their unblocking methods, they can be mainly classified into water-soluble, acid-soluble, oil-soluble, and biodegradable temporary plugging agents. Among these, oil-soluble temporary plugging agents are generally made of resins, paraffin wax, and other materials, possessing a certain pressure resistance, but they are thermoplastic and easily soften at high temperatures, making them unsuitable for pressure-driven water injection operations. Other types of temporary plugging agents cannot simultaneously meet the requirements of pressure-driven water injection in terms of temperature resistance, pressure resistance, dissolution, and sealing time. Pressure-driven water injection processes require temperatures above 150℃, pressure differential resistance of 20MPa, slow dissolution, and a temporary plugging time of 15–40 days.

[0008] Chinese patent application CN115850573A discloses a water-soluble particulate temporary plugging agent, which consists of 15%–20% acrylamide, 1%–2% methyl acrylate, 0.5%–1% crosslinking agent, 0.15%–1.1% initiator, 2%–5% miscible solvent, 0.02%–0.03% co-solvent, and the balance being water. This temporary plugging agent dissolves rapidly in water, with a dissolution time of 15–20 minutes, resulting in a short plugging time that cannot meet the time requirements of pressure-driven operations.

[0009] Chinese patent application CN115838589A discloses a gel-like particulate temporary plugging agent, comprising 4%–10% polyvinyl alcohol, 0.03%–0.05% aldehyde crosslinking agent, 0.2%–0.4% potential acid catalyst, and the balance being water. This temporary plugging agent exhibits low plugging strength, a plugging pressure of 6.03 MPa, and is suitable for temperatures of 90–120℃ and a salinity ≤4×10⁻⁶. 4 Formations with a concentration of mg / L cannot meet the design requirements of pressure-driven water injection processes in terms of pressure bearing capacity and temperature resistance.

[0010] Chinese patent application CN115895617A discloses a fiber-based temporary plugging agent, which is a water-soluble temporary plugging agent comprising a polyvinyl alcohol fiber matrix and sodium silicate uniformly dispersed in the polyvinyl alcohol fiber matrix; the mass of the sodium silicate is 25-35% of the total mass of the fiber-based temporary plugging agent. This fiber-based temporary plugging agent exhibits good unblocking effect at high temperatures of 140-160℃, with a dissolution time of 20.5-23.8 hours. Its dissolution conditions and effects are suitable for high-temperature reservoir fracturing. However, its breakthrough pressure is 10-18.7 MPa, which is insufficient to meet the pressure resistance and plugging time requirements of hydraulic fracturing and water injection processes.

[0011] Chinese patent application CN109401739A discloses a high-temperature resistant shielding temporary plugging agent, which is an acid-soluble temporary plugging agent. The components, by weight, include 100 parts particulate material; 5-20 parts elastic material; 5-20 parts filler material; 5-15 parts fiber material; and 1-5 parts micro / nano material. This temporary plugging agent can withstand temperatures up to 200℃ and pressures greater than 10MPa. Its acid solubility in 15wt% hydrochloric acid is greater than 80%, demonstrating good temperature resistance. However, its pressure resistance is insufficient to meet the requirements of pressure-driven water injection processes.

[0012] Chinese patent application CN115960593A discloses a biodegradable temporary plugging agent. The agent is knot-shaped and composed of 72-80 parts biodegradable resin, 12-20 parts modified polyethylene glycol, 1-5 parts nanoparticle toughening agent, 1-5 parts salt toughening agent, and 1-3 parts water-blocking agent. While this temporary plugging agent improves plugging time to some extent, it is mainly suitable for low-temperature reservoirs at 20-60℃, and the knot's outer diameter is 13-18 mm. It is typically suitable for borehole plugging and has poor applicability for temporary plugging in pressure-driven fractures in high-temperature reservoirs.

[0013] Chinese patent application CN115820232A discloses a biodegradable temporary plugging agent. The raw materials used are complex, including 60-80 wt% polyethylene glycol, 15-25 wt% polyvinyl alcohol, 0.5-2 wt% zinc stearate, 0.5-2 wt% 2-acrylamido-2-methylpropanesulfonic acid, 4-10 wt% polybutylene succinate, 0.1-0.5 wt% triacetin, 0.1-0.5 wt% tributyl citrate, 0.3-0.7 wt% polyethylene wax, 0.1-0.5 wt% cationic starch, 0.1-0.3 wt% sepiolite fiber, 1.0-3.0 wt% calcium carbonate, 0.5-1.0 wt% hexamethylenetetramine, and 0.5-1.0 wt% trimethylallyl ammonium chloride. The aforementioned biodegradable temporary plugging agent is suitable for reservoirs at 110–120°C and can withstand pressures of over 50 MPa. However, it has many components, is complex to prepare, dissolves rapidly at high temperatures, and the higher the temperature, the faster the dissolution. The dissolution time is 7 hours above 100°C, resulting in a short plugging time that cannot meet the plugging time requirements of the pressure-driven water injection process.

[0014] In summary, existing temporary plugging agents are mainly used in fracturing and acidizing operations, with fewer applications in hydraulic pressure injection processes. However, hydraulic pressure injection differs significantly from fracturing and acidizing operations, involving not only higher injection pressures but also longer operation cycles. Therefore, temporary plugging agents used in hydraulic pressure injection require not only strong pressure resistance but also long sealing duration. Consequently, there is an urgent need to develop an anti-channeling temporary plugging system suitable for hydraulic pressure injection processes. Summary of the Invention

[0015] The technical problem this application aims to solve is that during hydraulic fracturing and water injection, the high injection pressure can easily lead to excessive extension of the main fracture, causing oil-water well penetration and premature water channeling. Hydraulic fracturing operations involve high injection pressure and long operation cycles, therefore, the temporary plugging agents used in hydraulic fracturing need to withstand temperatures above 150℃, pressure differentials of 20MPa, slow dissolution, and a temporary plugging time of 15–40 days. Currently, temporary plugging systems used in fracturing and acidizing are not suitable for hydraulic fracturing and water injection processes. Furthermore, hydraulic fracturing plugging cannot completely seal the area to allow for continued water injection and oil recovery after hydraulic fracturing, so current plugging agents are also unsuitable.

[0016] Purpose of the invention: The present invention addresses the problems existing in the prior art by disclosing slow-dissolving temporary plugging particles for pressure drive, their preparation method, anti-channeling temporary plugging system, and their applications.

[0017] Technical solution: Pressure-driven slow-dissolving temporary plugging particles, composed of hollow soluble metal alloy particles and a hydrophobic layer surrounding the outer surface of the hollow soluble metal alloy particles, wherein:

[0018] The hydrophobic layer is a cross-linked system formed by a network structuring agent and a coupling agent under ultraviolet irradiation in the presence of a catalyst.

[0019] The preparation method of the above-mentioned slow-dissolving and temporary plugging particles for pressure displacement, by weight, comprises the following steps:

[0020] (1) Place 80 parts of hollow soluble metal alloy particles in a reaction vessel, then add 2 to 10 parts of coupling agent, shake for at least 5 min, preferably 5 to 60 min, then add 2 to 8 parts of network structure agent, shake again for at least 5 min, preferably 5 to 30 min, to obtain the first fluid;

[0021] (2) Add 0.5 to 5 parts of catalyst to the first fluid, shake and mix to obtain the second fluid, pour out the second fluid and spread it evenly in a container, and irradiate it with an ultraviolet lamp for at least 10 minutes, preferably 10-240 minutes to obtain the slow-dissolving temporary plugging particles for pressure drive.

[0022] Slow-dissolving temporary plugging particles for pressure drive are prepared by any one of the above-described methods for preparing slow-dissolving temporary plugging particles for pressure drive.

[0023] The anti-channeling temporary blocking system, based on its total mass, consists of the following components:

[0024] 5% to 20% of the above-mentioned slow-dissolving and temporary plugging particles for pressure drive, 0.5% to 5% of nonionic surfactant, and the balance being water.

[0025] The aforementioned anti-channeling and temporary plugging system is used as an anti-channeling and temporary plugging agent in pressure-driven water injection exploitation of low-permeability oilfields.

[0026] The main improvements of this invention are:

[0027] 1. The soluble metal alloy particles were designed as hollow soluble metal alloy particles, and the composition of the hollow soluble metal alloy particles was improved: in order to slow down the dissolution rate of the metal particles, the aluminum content was increased from 5.0-10.0% to 10-20%.

[0028] 2. Improvement of the physical structure of hollow soluble metal alloy particles: Since the density of soluble metal alloy particles is between 1.5 and 2.0 g / cm³... 3 In the meantime, alloy particles sink and aggregate in water, making it difficult to inject them properly. This invention designs solid alloy plugging particles into a hollow structure, making their apparent density comparable to water, so that they can be self-suspended in water without the aid of any external objects, thus reducing the injection difficulty of the pressure-driven plugging system.

[0029] 3. The hollow soluble metal alloy particles were chemically modified: This chemical modification forms a hydrophobic layer on the outer surface of the metal particles, which prevents water from contacting the hollow soluble metal alloy particles, significantly reduces the hydrolysis reaction of the hollow soluble metal alloy particles, prolongs the temporary plugging time of the metal particles, and also effectively prevents the slow-dissolving temporary plugging particles used in the pressure drive in the anti-channeling temporary plugging system from agglomerating during the injection process.

[0030] Beneficial effects: The slow-dissolving temporary plugging particles for pressure drive, their preparation method, anti-channeling temporary plugging system, and applications disclosed in this invention have the following beneficial effects:

[0031] (1) Compared with conventional temporary plugging agents, the temporary plugging agent in this invention has higher pressure differential strength, stronger high temperature resistance, stronger salt resistance, and longer effective plugging time, which can reach 40 days.

[0032] (2) Compared with simple aluminum-magnesium alloy metal particles, the present invention does not require the addition of any substances and can be directly suspended in the oilfield injection water, reducing the difficulty of injection and reducing safety risks.

[0033] (3) Compared with simple aluminum-magnesium alloy metal particles, the present invention reacts more slowly in water with high mineralization and high temperature. During the on-site injection process, it will not release a large amount of hydrogen due to violent reaction, which will increase the construction risk. Attached Figure Description

[0034] Figure 1 This diagram illustrates the reaction conversion rate of pressure-driven slow-dissolving temporary plugging particles A prepared in Example 4 and soluble metal particles of the same size and composition as a control group in 50,000 mg / L standard saline solution at room temperature.

[0035] Figure 2This is a schematic diagram showing the reaction conversion rate of the slow-dissolving temporary plugging particles B prepared for pressure drive in Example 5 and the soluble metal particles of the same size and composition as the control group in 50000 mg / L standard saline at 45°C. Detailed Implementation

[0036] The specific embodiments of the present invention are described in detail below.

[0037] The "range" disclosed in this invention is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 10–50 is listed for a specific parameter, it is also expected that ranges of 10–40 and 20–50 are also included. Furthermore, if the minimum range values ​​are 1 and 2, and the maximum range values ​​are 3, 4, and 5, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, unless otherwise stated, the numerical range "a–b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0–5" means that all real numbers between "0–5" have been listed herein; "0–5" is merely a shortened representation of these numerical combinations.

[0038] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0039] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0040] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0041] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0042] Unless otherwise specified, the reaction will proceed under normal temperature and pressure conditions.

[0043] Unless otherwise specified, all parts or percentages are by weight or by weight percentage.

[0044] In this invention, all the substances used are known substances that can be purchased or synthesized by known methods.

[0045] In this invention, all the devices or equipment used are conventional devices or equipment known in the art and are readily available.

[0046] In this invention, the standard brine used conforms to the industry standard SY / T 5358-2010, "Evaluation Method for Reservoir Sensitivity Flow Tests," wherein:

[0047] The standard salt solution is formulated as NaCl:CaCl2:MgCl2·6H2O = 7:0.6:0.4 (mass ratio).

[0048] The pressure-driven slow-dissolving and temporary plugging particles consist of hollow soluble metal alloy particles and a hydrophobic layer surrounding the outer surface of the hollow soluble metal alloy particles, wherein:

[0049] The hydrophobic layer is a cross-linked system formed by a network structuring agent and a coupling agent under ultraviolet irradiation in the presence of a catalyst.

[0050] Furthermore, based on the total mass of the hollow soluble metal alloy particles, it consists of the following components:

[0051] The aluminum content is 10.0-20.0%, the manganese content is 0.1-1.0%, the carbon content is ≤0.05%, the nickel content is ≤0.01%, the calcium content is ≤0.005%, and the balance is magnesium.

[0052] Furthermore, the hollow soluble metal alloy particles are spherical hollow soluble metal alloy particles with a spherical internal cavity. The outer radius of the hollow soluble metal alloy particles is 50-450 μm, and the inner radius of the internal cavity is 45-380 μm. At this size, the hollow soluble metal alloy particles do not require any additional substances and can be directly suspended in the oilfield injection water, reducing injection difficulty and safety risks.

[0053] Furthermore, the hollow soluble metal alloy particles are elliptical hollow soluble metal alloy particles with an elliptical cavity. The major axis of the elliptical hollow soluble metal alloy particles is 70-500 μm, and the minor axis is 30-390 μm. The major axis of the elliptical inner cavity of the elliptical hollow soluble metal alloy particles is 60-460 μm, and the minor axis is 25-280 μm. At this size, the hollow soluble metal alloy particles do not require any additional substances and can be directly suspended in the oilfield injection water, reducing injection difficulty and safety risks.

[0054] Further, the coupling agent is one or more of vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-(phenylamino)propyltrimethoxysilane, γ-aminopropyltriethoxysilane, triethoxymethylsilane, acrylatepropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and 3-(2-aminoethylamino)propylmethyldimethoxysilane.

[0055] Furthermore, the thickness of the hydrophobic layer is controlled within 5 μm, preferably 0.01-1 μm.

[0056] Furthermore, the structural formula of the network architecture agent is one of R1-CH=CH-CH=CH-R2 or R3-CH=CH-CH2-CH=CH-R4, wherein:

[0057] R1, R2, R3, and R4 are each independently selected from H and C5-C18 chain alkane groups, and R1 and R2 cannot both be H.

[0058] Further, the catalyst is one or more of 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, benzoin dimethyl ether, 2-hydroxy-1-(4-(2-hydroxy-2-methylpropanoylphenyl)benzyl)-2-methyl-1-propanone, methyl benzoylformate, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzophenone, and 2,4-dihydroxybenzophenone.

[0059] The preparation method of the above-mentioned slow-dissolving and temporary plugging particles for pressure displacement, by weight, comprises the following steps:

[0060] (1) Place 80 parts of hollow soluble metal alloy particles in a reaction vessel, then add 2 to 10 parts of coupling agent, shake for at least 5 minutes, preferably 5 to 60 minutes, then add 2 to 8 parts of network structure agent, shake again for at least 5 minutes, preferably 5 to 30 minutes to obtain the first fluid;

[0061] (2) Add 0.5 to 5 parts of catalyst to the first fluid, shake and mix to obtain the second fluid, pour out the second fluid and spread it evenly in a container, and irradiate it with an ultraviolet lamp for at least 10 minutes, preferably 10 to 240 minutes to obtain the slow-dissolving temporary plugging particles for pressure drive.

[0062] Further, the coupling agent in step (1) is one or more of vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-(phenylamino)propyltrimethoxysilane, γ-aminopropyltriethoxysilane, triethoxymethylsilane, acrylatepropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and 3-(2-aminoethylamino)propylmethyldimethoxysilane.

[0063] Further, the network architecture agent described in step (1) is one or more of the structural formulas R1-CH=CH-CH=CH-R2 and R3-CH=CH-CH2-CH=CH-R4, wherein:

[0064] R1, R2, R3, and R4 are each independently selected from H and C5-C18 chain alkane groups, and R1 and R2 cannot both be H.

[0065] Furthermore, based on the total mass of the hollow soluble metal alloy particles, the hollow soluble metal alloy particles described in step (1) consist of the following components:

[0066] The metal contains 10.0-20.0% aluminum, 0.1-1.0% manganese, ≤0.05% carbon, ≤0.01% nickel, ≤0.005% calcium, and the balance is magnesium.

[0067] Furthermore, the hollow soluble metal alloy particles mentioned in step (1) are spherical hollow soluble metal alloy particles with a spherical internal cavity. The outer radius of the hollow soluble metal alloy particles is 50-450 μm, and the inner radius of the internal cavity is 45-380 μm. At this size, the hollow soluble metal alloy particles do not require any additional substances and can be directly suspended in the oilfield injection water, reducing injection difficulty and safety risks.

[0068] Furthermore, the hollow soluble metal alloy particles mentioned in step (1) are elliptical hollow soluble metal alloy particles with an elliptical cavity. The major axis of the elliptical hollow soluble metal alloy particles is 70-500 μm, and the minor axis is 30-390 μm. The major axis of the elliptical inner cavity of the elliptical hollow soluble metal alloy particles is 60-460 μm, and the minor axis is 30-280 μm. At this size, the hollow soluble metal alloy particles do not require any additional substances and can be directly suspended in the oilfield injection water, reducing injection difficulty and safety risks.

[0069] Furthermore, the process requirements for ultraviolet lamp irradiation in step (2) are as follows:

[0070] The UV lamp power is at least 15W, preferably 15-100W, and the distance between the UV lamp and the second fluid is no more than 40 cm, preferably 10-40 cm.

[0071] Further, the catalyst mentioned in step (2) is one or more of 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, benzoin dimethyl ether, 2-hydroxy-1-(4-(2-hydroxy-2-methylpropanoylphenyl)benzyl)-2-methyl-1-propanone, methyl benzoylformate, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzophenone, and 2,4-dihydroxybenzophenone.

[0072] Furthermore, in step (2), the catalyst is first dissolved in an organic solvent and then added to the first fluid, wherein:

[0073] The amount of organic solvent added is 1-5 ml / g based on the weight of the catalyst;

[0074] The organic solvent is one or more of methanol, ethanol, isopropanol, benzene, toluene, and xylene.

[0075] Slow-dissolving temporary plugging particles for pressure drive are prepared by any one of the above-described methods for preparing slow-dissolving temporary plugging particles for pressure drive.

[0076] The anti-channeling temporary blocking system, based on its total mass, consists of the following components:

[0077] 5% to 20% of the above-mentioned slow-dissolving and temporary plugging particles for pressure drive, 0.5% to 5% of nonionic surfactant, and the balance being water.

[0078] Furthermore, the nonionic surfactant is one or more of polyoxyethylene fatty alcohol ethers, polyoxyethylene fatty acid esters, alkylphenol polyoxyethylene ethers, alkylolamides, alcohol ether glycosides, and polyoxyethylene alkylolamides.

[0079] The aforementioned anti-channeling and temporary plugging system is used as an anti-channeling and temporary plugging agent in pressure-driven water injection exploitation of low-permeability oilfields.

[0080] During pressure-driven water injection operations, displacement fluid is injected through pressure-driven injection wells at a rate greater than the formation's absorption capacity.

[0081] After the main fracture of the formation is opened, the above-mentioned anti-channeling temporary plugging system is directly added to the injected fluid. When the injection pressure starts to rise significantly or reaches the preset threshold, the addition of the above-mentioned anti-channeling temporary plugging system is stopped, and water injection pressure drive continues.

[0082] After the pressure drive is completed, acid dissolution can be used to unblock the blockage or not, depending on the site requirements.

[0083] Example 1

[0084] The pressure-driven slow-dissolving and temporary plugging particles consist of hollow soluble metal alloy particles and a hydrophobic layer surrounding the outer surface of the hollow soluble metal alloy particles, wherein:

[0085] The hydrophobic layer is a cross-linked system formed by a network structuring agent and a coupling agent under ultraviolet irradiation in the presence of a catalyst.

[0086] Furthermore, based on the total mass of the hollow soluble metal alloy particles, it consists of the following components:

[0087] The metal contains 10.0% aluminum, 0.1% manganese, 0.03% carbon, 0.005% nickel, 0.004% calcium, and the balance is magnesium.

[0088] Furthermore, the hollow soluble metal alloy particle is a spherical hollow soluble metal alloy particle with a spherical internal cavity. The outer radius of the hollow soluble metal alloy particle is 50 μm, and the inner radius of the inner cavity of the hollow soluble metal alloy particle is 45 μm.

[0089] In another embodiment, the hollow soluble metal alloy particle is an elliptical hollow soluble metal alloy particle with an elliptical cavity. The major axis of the elliptical hollow soluble metal alloy particle is 70 μm, the minor axis is 30 μm, and the major axis of the elliptical inner cavity of the elliptical hollow soluble metal alloy particle is 60 μm, and the minor axis is 25 μm.

[0090] Furthermore, the coupling agent is vinyltrichlorosilane.

[0091] Furthermore, the thickness of the hydrophobic layer is controlled at 0.01 μm.

[0092] Furthermore, the structural formula of the network architecture agent is R1-CH=CH-CH=CH-R2, where:

[0093] R1 is H;

[0094] R2 is n-pentyl.

[0095] Furthermore, the catalyst is 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide.

[0096] The preparation method of the above-mentioned slow-dissolving and temporary plugging particles for pressure displacement, by weight, comprises the following steps:

[0097] (1) Place 80 parts of hollow soluble metal alloy particles in a reaction vessel, then add 2 parts of coupling agent, shake for 50 min, add 2 parts of network structure agent, shake for 5 min again to obtain the first fluid;

[0098] (2) Add 0.5 parts of catalyst to the first fluid, shake and mix to obtain the second fluid, pour out the second fluid and spread it evenly in a container, and irradiate it with an ultraviolet lamp for 10 minutes to obtain the slow-dissolving temporary plugging particles for pressure drive.

[0099] Further, the coupling agent in step (1) is vinyltrichlorosilane.

[0100] Further, the structural formula of the network architecture agent described in step (1) is R1-CH=CH-CH=CH-R2, where:

[0101] R1 is H;

[0102] R2 is n-pentyl.

[0103] Furthermore, based on the total mass of the hollow soluble metal alloy particles, the hollow soluble metal alloy particles described in step (1) consist of the following components:

[0104] The metal contains 10.0% aluminum, 0.1% manganese, 0.03% carbon, 0.005% nickel, 0.004% calcium, and the balance is magnesium.

[0105] Furthermore, the hollow soluble metal alloy particles in step (1) are spherical hollow soluble metal alloy particles with spherical internal cavities. The outer radius of the hollow soluble metal alloy particles is 50 μm, and the inner radius of the inner cavity of the hollow soluble metal alloy particles is 45 μm.

[0106] In another embodiment, the hollow soluble metal alloy particles in step (1) are elliptical hollow soluble metal alloy particles with elliptical cavities. The major axis of the elliptical hollow soluble metal alloy particles is 70 μm and the minor axis is 30 μm. The major axis of the elliptical hollow soluble metal alloy particles is 60 μm and the minor axis is 30 μm.

[0107] Furthermore, the process requirements for ultraviolet lamp irradiation in step (2) are as follows:

[0108] The UV lamp has a power of 15W, and the distance between the UV lamp and the second fluid is 40 cm.

[0109] Further, the catalyst in step (2) is 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide.

[0110] Furthermore, in step (2), the catalyst is first dissolved in an organic solvent and then added to the first fluid, wherein:

[0111] The amount of organic solvent added is 1 ml / g based on the weight of the catalyst;

[0112] The organic solvent is methanol.

[0113] Slow-dissolving temporary plugging particles for pressure drive are prepared by any one of the above-described methods for preparing slow-dissolving temporary plugging particles for pressure drive.

[0114] The anti-channeling temporary blocking system, based on its total mass, consists of the following components:

[0115] 5% of the above-mentioned slow-dissolving temporary plugging particles for pressure drive, 0.5% of nonionic surfactant, and the balance being water.

[0116] Furthermore, the nonionic surfactant is a polyoxyethylene fatty alcohol ether.

[0117] The aforementioned anti-channeling and temporary plugging system is used as an anti-channeling and temporary plugging agent in pressure-driven water injection exploitation of low-permeability oilfields.

[0118] Example 2

[0119] The pressure-driven slow-dissolving and temporary plugging particles consist of hollow soluble metal alloy particles and a hydrophobic layer surrounding the outer surface of the hollow soluble metal alloy particles, wherein:

[0120] The hydrophobic layer is a cross-linked system formed by a network structuring agent and a coupling agent under ultraviolet irradiation in the presence of a catalyst.

[0121] Furthermore, based on the total mass of the hollow soluble metal alloy particles, it consists of the following components:

[0122] The metal contains 20.0% aluminum, 1.0% manganese, 0.05% carbon, 0.01% nickel, 0.005% calcium, and the balance is magnesium.

[0123] Furthermore, the hollow soluble metal alloy particle is a spherical hollow soluble metal alloy particle with a spherical internal cavity. The outer radius of the hollow soluble metal alloy particle is 450 μm, and the inner radius of the inner cavity of the hollow soluble metal alloy particle is 380 μm.

[0124] In another embodiment, the hollow soluble metal alloy particle is an elliptical hollow soluble metal alloy particle with an elliptical cavity. The major axis of the elliptical hollow soluble metal alloy particle is 500 μm, the minor axis is 390 μm, and the major axis of the elliptical inner cavity of the elliptical hollow soluble metal alloy particle is 460 μm, and the minor axis is 280 μm.

[0125] Furthermore, the coupling agent is vinyltrimethoxysilane.

[0126] Furthermore, the thickness of the hydrophobic layer is 5 μm.

[0127] Further, the network architecture agent is a mixture of R1-CH=CH-CH=CH-R2 and R3-CH=CH-CH2-CH=CH-R4 in equal mass ratios, wherein:

[0128] R1 is n-octadecyl group

[0129] R2 is H;

[0130] R3 is H;

[0131] R4 is isopentyl.

[0132] Furthermore, the catalyst is 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0133] The preparation method of the above-mentioned slow-dissolving and temporary plugging particles for pressure displacement, by weight, comprises the following steps:

[0134] (1) Place 80 parts of hollow soluble metal alloy particles in a reaction vessel, then add 10 parts of coupling agent, shake for 60 min, add 8 parts of network structure agent, shake again for 30 min to obtain the first fluid;

[0135] (2) Add 5 parts of catalyst to the first fluid, shake and mix to obtain the second fluid, pour out the second fluid and spread it evenly in a container, and after irradiating with ultraviolet lamp for 240 min, the slow-dissolving temporary plugging particles for pressure drive are obtained.

[0136] Further, the coupling agent in step (1) is vinyltrimethoxysilane.

[0137] Further, the network architecture agent described in step (1) is a mixture of R1-CH=CH-CH=CH-R2 and R3-CH=CH-CH2-CH=CH-R4 in equal mass ratios, wherein:

[0138] R1 is n-octadecyl group

[0139] R2 is H;

[0140] R3 is H;

[0141] R4 is isopentyl.

[0142] Furthermore, based on the total mass of the hollow soluble metal alloy particles, the hollow soluble metal alloy particles described in step (1) consist of the following components:

[0143] The metal contains 20.0% aluminum, 1.0% manganese, 0.05% carbon, 0.01% nickel, 0.005% calcium, and the balance is magnesium.

[0144] Furthermore, the hollow soluble metal alloy particles in step (1) are spherical hollow soluble metal alloy particles with spherical internal cavities. The outer radius of the hollow soluble metal alloy particles is 450 μm, and the inner radius of the inner cavity of the hollow soluble metal alloy particles is 380 μm.

[0145] In another embodiment, the hollow soluble metal alloy particles in step (1) are elliptical hollow soluble metal alloy particles with elliptical cavities. The major axis of the elliptical hollow soluble metal alloy particles is 500 μm, the minor axis is 390 μm, and the major axis of the elliptical inner cavity of the elliptical hollow soluble metal alloy particles is 460 μm, and the minor axis is 280 μm.

[0146] Furthermore, the process requirements for ultraviolet lamp irradiation in step (2) are as follows:

[0147] The UV lamp has a power of 100W, and the distance between the UV lamp and the second fluid is 10 cm.

[0148] Further, the catalyst in step (2) is 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0149] Furthermore, in step (2), the catalyst is first dissolved in an organic solvent and then added to the first fluid, wherein:

[0150] The amount of organic solvent added is 5 ml / g based on the weight of the catalyst;

[0151] The organic solvent is ethanol.

[0152] Slow-dissolving temporary plugging particles for pressure drive are prepared by any one of the above-described methods for preparing slow-dissolving temporary plugging particles for pressure drive.

[0153] The anti-channeling temporary blocking system, based on its total mass, consists of the following components:

[0154] 20% of the above-mentioned slow-dissolving and temporary plugging particles for pressure drive, 5% of nonionic surfactant, and the balance is water.

[0155] Furthermore, the nonionic surfactant is a polyoxyethylene fatty acid ester.

[0156] The aforementioned anti-channeling and temporary plugging system is used as an anti-channeling and temporary plugging agent in pressure-driven water injection exploitation of low-permeability oilfields.

[0157] Example 3

[0158] The pressure-driven slow-dissolving and temporary plugging particles consist of hollow soluble metal alloy particles and a hydrophobic layer surrounding the outer surface of the hollow soluble metal alloy particles, wherein:

[0159] The hydrophobic layer is a cross-linked system formed by a network structuring agent and a coupling agent under ultraviolet irradiation in the presence of a catalyst.

[0160] Furthermore, based on the total mass of the hollow soluble metal alloy particles, it consists of the following components:

[0161] The metal contains 15% aluminum, 0.5% manganese, 0.01% carbon, 0.01% nickel, 0.005% calcium, and the balance is magnesium.

[0162] Furthermore, the hollow soluble metal alloy particle is a spherical hollow soluble metal alloy particle with a spherical internal cavity. The outer radius of the hollow soluble metal alloy particle is 250 μm, and the inner radius of the inner cavity of the hollow soluble metal alloy particle is 210 μm.

[0163] In another embodiment, the hollow soluble metal alloy particle is an elliptical hollow soluble metal alloy particle with an elliptical cavity. The major axis of the elliptical hollow soluble metal alloy particle is 280 μm, the minor axis is 210 μm, and the major axis of the elliptical inner cavity of the elliptical hollow soluble metal alloy particle is 210 μm, and the minor axis is 150 μm.

[0164] Further, the coupling agent is vinyltriethoxysilane. In another embodiment, the coupling agent is 3-(phenylamino)propyltrimethoxysilane. In another embodiment, the coupling agent is γ-aminopropyltriethoxysilane. In another embodiment, the coupling agent is triethoxymethylsilane. In another embodiment, the coupling agent is acrylatepropyltrimethoxysilane. In another embodiment, the coupling agent is γ-chloropropyltriethoxysilane. In another embodiment, the coupling agent is γ-methacryloyloxypropyltrimethoxysilane. In another embodiment, the coupling agent is 3-(2-aminoethylamino)propylmethyldimethoxysilane. In another embodiment, the coupling agent is a mixture of vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-(phenylamino)propyltrimethoxysilane, γ-aminopropyltriethoxysilane, triethoxymethylsilane, acrylatepropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and 3-(2-aminoethylamino)propylmethyldimethoxysilane in equal mass ratios.

[0165] Furthermore, the thickness of the hydrophobic layer is 1 μm.

[0166] Further, the network architecture agent is a mixture of R1-CH=CH-CH=CH-R2 and R3-CH=CH-CH2-CH=CH-R4 in equal mass ratios, wherein:

[0167] R1 is isopentyl;

[0168] R2 is n-octadecyl;

[0169] R3 is isopentyl;

[0170] R4 is n-octadecyl.

[0171] In another embodiment, the network architecture agent is a mixture of R1-CH=CH-CH=CH-R2 and R3-CH=CH-CH2-CH=CH-R4 in equal mass ratios, wherein:

[0172] R1 is isopentyl;

[0173] R2 is H;

[0174] R3 is H;

[0175] R4 is H.

[0176] Further, the catalyst is benzoin dimethyl ether. In another embodiment, the catalyst is 2-hydroxy-1-(4-(2-hydroxy-2-methylpropionylphenyl)benzyl)-2-methyl-1-propanone. In another embodiment, the catalyst is methyl benzoylformate. In another embodiment, the catalyst is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide. In another embodiment, the catalyst is benzophenone. In another embodiment, the catalyst is 2,4-dihydroxybenzophenone. In another embodiment, the catalyst is a mixture of 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, benzoin dimethyl ether, 2-hydroxy-1-(4-(2-hydroxy-2-methylpropanoylphenyl)benzyl)-2-methyl-1-propanone, methyl benzoylformate, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzophenone, and 2,4-dihydroxybenzophenone in equal mass ratios.

[0177] The preparation method of the above-mentioned slow-dissolving and temporary plugging particles for pressure displacement, by weight, comprises the following steps:

[0178] (1) Place 80 parts of hollow soluble metal alloy particles in a reaction vessel, then add 6 parts of coupling agent, shake for 30 min, add 5 parts of network structure agent, shake again for 15 min to obtain the first fluid;

[0179] (2) Add 3 parts of catalyst to the first fluid, shake and mix to obtain the second fluid, pour out the second fluid and spread it evenly in a container, and after irradiating with ultraviolet lamp for 120 minutes, the slow-dissolving temporary plugging particles for pressure drive are obtained.

[0180] Further, the coupling agent in step (1) is vinyltriethoxysilane. In another embodiment, the coupling agent in step (1) is 3-(phenylamino)propyltrimethoxysilane. In another embodiment, the coupling agent in step (1) is γ-aminopropyltriethoxysilane. In another embodiment, the coupling agent in step (1) is triethoxymethylsilane. In another embodiment, the coupling agent in step (1) is acrylatepropyltrimethoxysilane. In another embodiment, the coupling agent in step (1) is γ-chloropropyltriethoxysilane. In another embodiment, the coupling agent in step (1) is γ-methacryloyloxypropyltrimethoxysilane. In another embodiment, the coupling agent in step (1) is 3-(2-aminoethylamino)propylmethyldimethoxysilane. In another embodiment, the coupling agent in step (1) is a mixture of vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-(phenylamino)propyltrimethoxysilane, γ-aminopropyltriethoxysilane, triethoxymethylsilane, acrylatepropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and 3-(2-aminoethylamino)propylmethyldimethoxysilane in equal mass ratios.

[0181] Further, the network architecture agent in step (1) is a mixture of R1-CH=CH-CH=CH-R2 and R3-CH=CH-CH2-CH=CH-R4 in equal mass ratios, wherein:

[0182] R1 is isopentyl;

[0183] R2 is n-octadecyl;

[0184] R3 is isopentyl;

[0185] R4 is n-octadecyl.

[0186] In another embodiment, the network architecture agent in step (1) is a mixture of R1-CH=CH-CH=CH-R2 and R3-CH=CH-CH2-CH=CH-R4 in equal mass ratios, wherein:

[0187] R1 is isopentyl;

[0188] R2 is H;

[0189] R3 is H;

[0190] R4 is H.

[0191] Furthermore, based on the total mass of the hollow soluble metal alloy particles, the hollow soluble metal alloy particles described in step (1) consist of the following components:

[0192] The metal contains 15% aluminum, 0.5% manganese, 0.01% carbon, 0.01% nickel, 0.005% calcium, and the balance is magnesium.

[0193] Furthermore, the hollow soluble metal alloy particles in step (1) are spherical hollow soluble metal alloy particles with spherical internal cavities. The outer radius of the hollow soluble metal alloy particles is 250 μm, and the inner radius of the inner cavity of the hollow soluble metal alloy particles is 210 μm.

[0194] In another embodiment, the hollow soluble metal alloy particles in step (1) are elliptical hollow soluble metal alloy particles with elliptical cavities. The major axis of the elliptical hollow soluble metal alloy particles is 280 μm and the minor axis is 210 μm. The major axis of the elliptical inner cavity of the elliptical hollow soluble metal alloy particles is 210 μm and the minor axis is 150 μm.

[0195] Furthermore, the process requirements for ultraviolet lamp irradiation in step (2) are as follows:

[0196] The UV lamp has a power of 60W, and the distance between the UV lamp and the second fluid is 20 cm.

[0197] Further, the catalyst in step (2) is benzoin dimethyl ether. In another embodiment, the catalyst in step (2) is 2-hydroxy-1-(4-(2-hydroxy-2-methylpropionylphenyl)benzyl)-2-methyl-1-propanone. In another embodiment, the catalyst in step (2) is methyl benzoylformate. In another embodiment, the catalyst in step (2) is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide. In another embodiment, the catalyst in step (2) is benzophenone. In another embodiment, the catalyst in step (2) is 2,4-dihydroxybenzophenone. In another embodiment, the catalyst in step (2) is a mixture of 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, benzoin dimethyl ether, 2-hydroxy-1-(4-(2-hydroxy-2-methylpropanoylphenyl)benzyl)-2-methyl-1-propanone, methyl benzoylformate, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzophenone, and 2,4-dihydroxybenzophenone in equal mass ratios.

[0198] Furthermore, in step (2), the catalyst is first dissolved in an organic solvent and then added to the first fluid, wherein:

[0199] The amount of organic solvent added is 3 ml / g based on the weight of the catalyst;

[0200] The organic solvent is benzene. In another embodiment, the organic solvent is toluene. In another embodiment, the organic solvent is xylene. In yet another embodiment, the organic solvent is a mixture of methanol, ethanol, isopropanol, benzene, toluene, and xylene in equal volume ratios.

[0201] Slow-dissolving temporary plugging particles for pressure drive are prepared by any one of the above-described methods for preparing slow-dissolving temporary plugging particles for pressure drive.

[0202] The anti-channeling temporary blocking system, based on its total mass, consists of the following components:

[0203] 10% of the above-mentioned slow-dissolving and temporary plugging particles for pressure drive, 3% of nonionic surfactant, and the balance is water.

[0204] Further, the nonionic surfactant is an alkylphenol polyoxyethylene ether. In another embodiment, the nonionic surfactant is an alkylolamide. In another embodiment, the nonionic surfactant is an alcohol ether glycoside. In another embodiment, the nonionic surfactant is a polyoxyethylene alkylolamide. In yet another embodiment, the nonionic surfactant is a mixture of polyoxyethylene fatty alcohol ether, polyoxyethylene fatty acid ester, alkylphenol polyoxyethylene ether, alkylolamide, alcohol ether glycoside, and polyoxyethylene alkylolamide in equal mass ratios.

[0205] The aforementioned anti-channeling and temporary plugging system is used as an anti-channeling and temporary plugging agent in pressure-driven water injection exploitation of low-permeability oilfields.

[0206] Example 4:

[0207] The preparation method of slow-dissolving temporary plugging particles for pressure displacement includes the following steps:

[0208] (1) Place 80g of hollow soluble metal alloy particles in a reaction vessel, then add 2g of vinyltriethoxysilane, shake for 30min, add 3g of network structuring agent, shake again for 5min to obtain the first fluid;

[0209] (2) Add 0.5g of 2-hydroxy-1-(4-(2-hydroxy-2-methylpropionylphenyl)benzyl)-2-methyl-1-propanone to 2mL of ethanol, dissolve and stir evenly, then add to the first fluid, shake and mix to obtain the second fluid, pour out the second fluid and spread it evenly in a container (such as a ceramic tray), and irradiate with a UV lamp for 20min to obtain pressure-driven slow-dissolving temporary plugging particles A.

[0210] Furthermore, the network architecture agent has R3-CH=CH-CH2-CH=CH-R4, where: R3 is isooctyl; R4 is H.

[0211] Furthermore, based on the total mass of the hollow soluble metal alloy particles, the hollow soluble metal alloy particles described in step (1) consist of the following components:

[0212] The metal contains 10% aluminum, 0.3% manganese, 0.05% carbon, 0.01% nickel, 0.005% calcium, and the balance is magnesium.

[0213] Furthermore, the hollow soluble metal alloy particles mentioned in step (1) are spherical hollow soluble metal alloy particles with a spherical internal cavity. The outer radius of the hollow soluble metal alloy particles is 100 μm, and the inner radius of the inner cavity of the hollow soluble metal alloy particles is 80 μm. At this size, the hollow soluble metal alloy particles do not require the addition of any additional substances and can be directly suspended in the oilfield injection water, reducing injection difficulty and safety risks.

[0214] Furthermore, the process requirements for ultraviolet lamp irradiation in step (2) are as follows:

[0215] The UV lamp has a power of 100W and the distance between the UV lamp and the second fluid is 20 cm.

[0216] Example 5:

[0217] The preparation method of slow-dissolving temporary plugging particles for pressure displacement, by weight, includes the following steps:

[0218] (1) Place 80g of hollow soluble metal alloy particles in a reaction vessel, then add 3g of vinyltrichlorosilane, shake for 30min, add 2g of 1,5-pentadiene, shake again for 20min to obtain the first fluid;

[0219] (2) Dissolve 1g of 2-hydroxy-2-methyl-1-phenyl-1-propanone and 1g of benzoin dimethyl ether in 5mL of isopropanol. After dissolving, stir evenly and add to the first fluid. After shaking and mixing, the second fluid is obtained. Pour out the second fluid and spread it evenly in a container (such as a ceramic tray). Irradiate with ultraviolet light for 30min to obtain pressure-driven slow-dissolving temporary plugging particles B.

[0220] Furthermore, based on the total mass of the hollow soluble metal alloy particles, the hollow soluble metal alloy particles described in step (1) consist of the following components:

[0221] The metal contains 10.0% aluminum, 1.0% manganese, 0.05% carbon, 0.005% nickel, 0.005% calcium, and the balance is magnesium.

[0222] Furthermore, the hollow soluble metal alloy particles mentioned in step (1) are spherical hollow soluble metal alloy particles with a spherical internal cavity. The outer radius of the hollow soluble metal alloy particles is 200 μm, and the inner radius of the inner cavity is 160 μm. At this size, the hollow soluble metal alloy particles do not require the addition of any additional substances and can be directly suspended in the oilfield injection water, reducing injection difficulty and safety risks.

[0223] Example 6

[0224] The preparation method of the anti-channeling and temporary blocking system includes the following steps:

[0225] S1: Pour 3g of polyoxyethylene fatty alcohol ether into 87g of water and stir until a mixture is obtained;

[0226] S2: Add 10g of the slow-dissolving temporary plugging particles A prepared in Example 4 to the mixture obtained in step S1, and stir evenly to obtain the anti-channeling temporary plugging system A.

[0227] Example 7

[0228] The preparation method of the anti-channeling and temporary blocking system includes the following steps:

[0229] S1: Pour 3g of polyoxyethylene fatty alcohol ether into 87g of water and stir until a mixture is obtained;

[0230] S2: Add 10g of the slow-dissolving temporary plugging particles B prepared in Example 5 to the mixture obtained in step S1, and stir evenly to obtain the anti-channeling temporary plugging system B.

[0231] Performance and Testing

[0232] First, the solubility of slow-dissolving metal alloy particles.

[0233] Solid soluble metal particles with the same composition and diameter as those in Examples 4 and 5 were used as control groups. They were also used together with the slow-dissolving temporary plugging particles A prepared in Example 4 and the slow-dissolving temporary plugging particles B prepared in Example 5 for pressure driving under different conditions to conduct dissolution experiments. During the dissolution experiments, sealed containers were used to collect hydrogen gas by water displacement. The reaction rate of the metal particles was calculated by the mass of hydrogen gas.

[0234] (1) Conversion rate of soluble metal particles in 50000 mg / L standard saline solution at room temperature

[0235] Take 10g of the slow-dissolving temporary plugging particles A prepared in Example 4, add 90g of 50000mg / L standard saline, place at room temperature (25℃) to carry out the dissolution reaction, and collect hydrogen gas, and record the amount of hydrogen gas collected at regular intervals.

[0236] Take 10g of solid spherical soluble metal particles with a radius of 100μm for a control experiment, add 90g of 50000mg / L standard saline, place at room temperature (25℃) to carry out the dissolution reaction, and collect hydrogen gas, and record the amount of hydrogen gas collected at regular intervals.

[0237] The composition of the soluble metal is as follows: 10% aluminum, 0.3% manganese, 0.05% carbon, 0.01% nickel, 0.005% calcium, and the balance is magnesium.

[0238] The reaction rates of the two soluble metal particles in a 50,000 mg / L standard saline solution at room temperature are as follows: Figure 1 As shown. From Figure 1 As can be seen, at room temperature and in 50,000 mg / L standard saline, the soluble metal particles, which served as the control group, reacted violently with the standard saline because they did not have a hydrophobic layer, and the reaction conversion rate was the highest at 88%. However, the pressure-driven slow-dissolving temporary plugging particles A prepared in Example 4 hardly reacted under the same conditions, and the reaction conversion rate after 30 days was <0.3%.

[0239] (2) Conversion rate of soluble metal particles in 50000 mg / L standard saline solution at 45℃

[0240] Take 10g of the slow-dissolving temporary plugging particles B prepared in Example 5, add 90g of 50000mg / L standard saline, place at 45℃ to carry out the dissolution reaction, and collect hydrogen gas, and record the amount of hydrogen gas collected at regular intervals.

[0241] A control experiment was conducted using 10g of solid spherical soluble metal particles with a radius of 200μm. 90g of 50000mg / L standard saline solution was added, and the mixture was placed at 45℃ to allow for a dissolution reaction. Hydrogen gas was collected, and the amount collected was recorded periodically. The soluble metal alloy particles consisted of the following components:

[0242] The metal contains 10.0% aluminum, 1.0% manganese, 0.05% carbon, 0.005% nickel, 0.005% calcium, and the balance is magnesium.

[0243] A control experiment was conducted using two types of soluble metal particles. The reaction rates of the two soluble metal particles in 50000 mg / L standard saline solution at 45°C are as follows: Figure 2 As shown. From Figure 2In the control group, the soluble metal particles, lacking a hydrophobic layer, reacted violently with the standard saline solution at 45°C and 50,000 mg / L, resulting in a higher reaction conversion rate of up to 92%. However, the pressure-driven slow-dissolving and temporary plugging particles B prepared in Example 5 showed almost no reaction under the same conditions, with a reaction conversion rate of <0.5% after 30 days.

[0244] Second, the blocking performance of the anti-channeling and temporary blocking system.

[0245] The anti-channeling temporary plugging system A prepared in Example 6, the anti-channeling temporary plugging system B prepared in Example 7, and a commonly used oilfield gel-type temporary plugging agent were used to conduct core plugging experiments using a core displacement device. After displacement for 1 day at 150℃ and a constant pressure difference of 20MPa, their fracture plugging rates were compared. The results are shown in Table 1.

[0246] Table 1. Evaluation Results of Plugging Performance

[0247]

[0248]

[0249] According to the core displacement effect test results, after displacement for 1 day at 150℃ and constant pressure of 20MPa, the fracture sealing rate of the anti-channeling temporary plugging system A and anti-channeling temporary plugging system B of the present invention, which are suitable for pressure drive in low-permeability reservoirs, is significantly higher than that of commonly used gel-type temporary plugging agents in oil fields.

[0250] Third: The differential pressure resistance of the anti-channeling and temporary blocking system

[0251] The anti-channeling temporary plugging system A prepared in Example 6, the anti-channeling temporary plugging system B prepared in Example 7, and a commonly used oilfield gel-type temporary plugging agent were used. Using a core displacement device, in an environment of 150℃, the injection pressure was gradually increased from 5 MPa to 45 MPa. The effects of pressure differential on the plugged section in the fracture were observed and tested to determine whether it was punctured. The results are shown in Table 2.

[0252] Table 2. Evaluation Results of Compressive Strength

[0253] Test object Pressure differential resistance (MPa) Anti-channeling temporary blocking system A ≥45 Anti-channeling temporary blocking system B ≥45 Commonly used gel-type temporary plugging agents in oil fields ≤5

[0254] According to the core displacement effect test results, the anti-channeling temporary plugging system A and anti-channeling temporary plugging system B of the present invention are suitable for pressure drive in low-permeability reservoirs, and their pressure-bearing capacity is significantly higher than that of commonly used gel-type temporary plugging agents in oil fields.

[0255] Fourth: The temporary blocking time of the anti-smuggling system

[0256] The anti-channeling temporary plugging system A prepared in Example 6 and the anti-channeling temporary plugging system B prepared in Example 7 were respectively used. Using a core displacement device, the system was displaced for 40 days in an environment of 150℃ and a constant pressure difference of 20MPa. After stabilization for different times, the fracture plugging rate was measured. The specific results are shown in Table 3.

[0257] Table 3. Evaluation Results of Compressive Strength

[0258]

[0259] According to the core displacement effect test results, the anti-channeling temporary plugging system A and anti-channeling temporary plugging system B of the present invention are suitable for pressure drive in low-permeability reservoirs, and their plugging time can reach 40 days.

[0260] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. Slow-dissolving temporary plugging particles for pressure displacement, characterized in that, It consists of hollow soluble metal alloy particles and a hydrophobic layer surrounding the outer surface of the hollow soluble metal alloy particles, wherein: The hydrophobic layer is a cross-linked system formed by a network structuring agent and a coupling agent under ultraviolet irradiation in the presence of a catalyst.

2. The slow-dissolving temporary plugging particles for pressure drive as described in claim 1, characterized in that, Based on the total mass of the hollow soluble metal alloy particles, it consists of the following components: The aluminum content is 10.0-20.0%, the manganese content is 0.1-1.0%, the carbon content is ≤0.05%, the nickel content is ≤0.01%, the calcium content is ≤0.005%, and the balance is magnesium.

3. The slow-dissolving temporary plugging particles for pressure drive as described in claim 1, characterized in that, The hollow soluble metal alloy particles are spherical hollow soluble metal alloy particles with spherical internal cavities. The outer radius of the hollow soluble metal alloy particles is 50-450 μm, and the inner radius of the internal cavity is 45-380 μm, or... The hollow soluble metal alloy particles are elliptical hollow soluble metal alloy particles with elliptical cavities. The major axis of the elliptical hollow soluble metal alloy particles is 70-500μm, the minor axis is 30-390μm, and the major axis of the elliptical inner cavity of the elliptical hollow soluble metal alloy particles is 60-460μm, and the minor axis is 25-280μm.

4. The method for preparing the slow-dissolving temporary plugging particles for pressure drive according to any one of claims 1-3, characterized in that, The steps are as follows, based on parts by weight: (1) Place 80 parts of hollow soluble metal alloy particles in a reaction vessel, then add 2 to 10 parts of coupling agent, shake for at least 5 minutes, preferably 5 to 60 minutes, then add 2 to 8 parts of network structure agent, shake again for at least 5 minutes, preferably 5 to 30 minutes to obtain the first fluid; (2) Add 0.5 to 5 parts of catalyst to the first fluid, shake and mix to obtain the second fluid, pour out the second fluid and spread it evenly in a container, and irradiate it with an ultraviolet lamp for at least 10 minutes, preferably 10 to 240 minutes to obtain the slow-dissolving temporary plugging particles for pressure drive.

5. The method for preparing slow-dissolving temporary plugging particles for pressure drive as described in claim 4, characterized in that, The coupling agent in step (1) is one or more of vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-(phenylamino)propyltrimethoxysilane, γ-aminopropyltriethoxysilane, triethoxymethylsilane, acrylatepropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and 3-(2-aminoethylamino)propylmethyldimethoxysilane.

6. The method for preparing slow-dissolving temporary plugging particles for pressure drive as described in claim 4, characterized in that, The network architecture agent mentioned in step (1) is one or more of the structural formulas R1-CH=CH-CH=CH-R2 and R3-CH=CH-CH2-CH=CH-R4, wherein: R1, R2, R3, and R4 are each independently selected from H and C5-C18 chain alkane groups, and R1 and R2 cannot both be H.

7. The method for preparing slow-dissolving temporary plugging particles for pressure drive as described in claim 4, characterized in that, Based on the total mass of the hollow soluble metal alloy particles, the hollow soluble metal alloy particles in step (1) are composed of the following components: The metal contains 10.0-20.0% aluminum, 0.1-1.0% manganese, ≤0.05% carbon, ≤0.01% nickel, ≤0.005% calcium, and the balance is magnesium.

8. The method for preparing slow-dissolving temporary plugging particles for pressure drive as described in claim 4, characterized in that, The hollow soluble metal alloy particles mentioned in step (1) are spherical hollow soluble metal alloy particles with spherical internal cavities. The outer radius of the hollow soluble metal alloy particles is 50-450 μm, and the inner radius of the internal cavity of the hollow soluble metal alloy particles is 45-380 μm, or... Further, the hollow soluble metal alloy particles mentioned in step (1) are elliptical hollow soluble metal alloy particles with elliptical cavities. The major axis of the elliptical hollow soluble metal alloy particles is 70-500μm, the minor axis is 30-390μm, and the major axis of the elliptical inner cavity of the elliptical hollow soluble metal alloy particles is 60-460μm, and the minor axis is 30-280μm.

9. The method for preparing slow-dissolving temporary plugging particles for pressure drive as described in claim 4, characterized in that, The process requirements for ultraviolet lamp irradiation in step (2) are as follows: The UV lamp power is at least 15W, preferably 15-100W, and the distance between the UV lamp and the second fluid is no more than 40 cm, preferably 10-40 cm.

10. The method for preparing slow-dissolving temporary plugging particles for pressure drive as described in claim 4, characterized in that, The catalyst mentioned in step (2) is one or more of 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, benzoin dimethyl ether, 2-hydroxy-1-(4-(2-hydroxy-2-methylpropionylphenyl)benzyl)-2-methyl-1-propanone, methyl benzoylformate, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzophenone, and 2,4-dihydroxybenzophenone, and / or In step (2), the catalyst is first dissolved in an organic solvent and then added to the first fluid, wherein: The amount of organic solvent added is 1-5 ml / g based on the weight of the catalyst; The organic solvent is one or more of methanol, ethanol, isopropanol, benzene, toluene, and xylene.

11. Slow-dissolving temporary plugging particles for pressure displacement, characterized in that, It is prepared by the method for preparing slow-dissolving temporary plugging particles for pressure drive as described in any one of claims 4-10.

12. A temporary blocking system for preventing cross-flow, characterized in that, The total mass of the aforementioned anti-channeling and temporary blocking system comprises the following components: 5% to 20% of the slow-dissolving and temporary plugging particles for pressure drive as described in any one of claims 1-3 and 11, 0.5% to 5% of nonionic surfactant, and the balance being water.

13. The anti-channeling temporary blocking system as described in claim 12, characterized in that, The nonionic surfactant is one or more of the following: polyoxyethylene fatty alcohol ether, polyoxyethylene fatty acid ester, alkylphenol polyoxyethylene ether, alkylolamide, alcohol ether glycoside, and polyoxyethylene alkylolamide.

14. The application of the anti-channeling temporary plugging system according to claim 12 or 13 as an anti-channeling temporary plugging agent in pressure-driven water injection exploitation of low-permeability oilfields.

Images