Water-inhibiting and channeling-preventing temporary plugging system for pressure driving and application thereof

Abstract

The invention discloses a water-inhibiting and channeling-preventing temporary plugging system for pressure driving, which comprises the following components in percentage by mass: 5-15% of water-soluble fiber and 5-15% of soluble metal alloy particles. And the soluble metal alloy particles account for 85-95%. The invention further discloses application of the water-inhibiting and channeling-preventing temporary plugging system for pressure flooding as a temporary plugging agent for pressure flooding in a low-permeability reservoir. The high-pressure-difference-resistant pressure-driving plugging agent has the advantages that (1) the high-pressure-difference-resistant strength is higher, the high-temperature-resistant capacity is higher, the temperature-resistant and salt-resistant capacity is higher, the effective plugging time is longer, and the long-time pressure-driving operation requirement can be better met; and (2) in the water injection pressure driving process, as soluble metal alloy components are gradually corroded into powdery particles with smaller particle sizes, particles formed at the rear edge of the plugging section can be continuously embedded into gaps of a temporary plugging material, and powdery particles formed at the front edge of the plugging section can enter deep small cracks or branch seams, so that the cracks are plugged more compactly, the plugging rate is higher, and the plugging effect is better. The plugging stability is higher, and the plugging effect is further guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield chemistry and oil and gas field development engineering, and in particular to a water suppression and anti-channeling temporary plugging system for pressure drive and application thereof. Background Art

[0002] China is rich in low-permeability oil resources, but the reservoir conditions of low-permeability oil reservoirs are complex and difficult to develop. They are characterized by low permeability, high seepage resistance, low production, rapid production decline, and slow energy replenishment.

[0003] In order to improve the production effect of low-permeability reservoirs, water injection and other measures are usually required to supplement the formation energy. However, in the process of water injection development of low-permeability reservoirs, there are generally problems such as high water injection pressure and high under-injection ratio, the contradiction of "no injection and no production" is prominent, effective displacement cannot be established between oil and water wells, the formation energy decreases rapidly, the production capacity decreases rapidly or even stops production.

[0004] In response to the above problems, the oil field combines hydraulic fracturing with water injection to form a pressure-driven water injection technology, which can increase the pore throat radius, increase the percolation distance, and quickly and effectively replenish the formation energy. It is an effective method that is expected to solve the dilemma of injection and production in low-permeability oil reservoirs, low recovery degree, and low oil production rate. For example, Chinese patent application CN 114439437A discloses a method for increasing the recovery rate of low-permeability oil reservoirs by water injection and pressure drive. The method includes the following steps: in the stage of increasing the injection pressure of the water well, determining the injection volume and injection time of the water well; in the stage of water well shut-in pressure diffusion, determining the water well shut-in time; in the stage of reducing the production pressure of the oil well, determining the oil well shut-in production time; in the stage of oil well shut-in pressure recovery, determining the oil well shut-in time; repeating the above steps to carry out multiple rounds of periodic production.

[0005] However, in the development of low-permeability reservoirs by pressure-driven water injection, the following problems exist: (1) fracture redirection is difficult, lateral microcracks are poorly opened, fractures are single, and the pressure-driven sweep coefficient is low, resulting in low oil recovery efficiency; (2) the main fracture is prone to excessive extension, leading to pressure penetration, resulting in penetration of oil and water wells, premature water breakthrough, and oil well shutdown.

[0006] In the face of the above problems, corresponding temporary plugging measures need to be taken to avoid excessive extension of the main cracks during water injection and pressure driving, resulting in single cracks or water channeling.

[0007] There are various types of temporary plugging agents at present. According to their morphology, they can be roughly divided into granular temporary plugging agents, fiber temporary plugging agents, rubber plug temporary plugging agents, etc.; according to the blocking method, they can be divided into water-soluble temporary plugging agents, acid-soluble temporary plugging agents, oil-soluble temporary plugging agents and degradable temporary plugging agents, etc. Among them:

[0008] Oil-soluble temporary plugging agents are generally made of resin, paraffin and other materials. They have a certain pressure-bearing capacity, but are thermoplastic and easily softened at high temperatures. They are usually only suitable for oil wells and are not suitable for water injection and pressure drive operations. Although other types of temporary plugging agents can be used for water injection and pressure drive, their performance in temperature resistance, pressure bearing, solubility, and plugging effect varies, and they need to be further improved in pressure drive applications.

[0009] For example, Chinese patent application CN115850573A discloses a water-soluble granular temporary plugging agent, which is composed of 15% to 20% acrylamide, 1% to 2% methyl acrylate, 0.5% to 1% cross-linking agent, 0.15% to 1.1% initiator, 2% to 5% mutual solvent, 0.02% to 0.03% solvent promoter and the balance of water. The temporary plugging agent requires a particle size of 140-210 meshes. If the particle size is too large, the plugging effect is not good, and if the particle size is too small, the plugging efficiency is low, and the amount and cost of the temporary plugging agent will be increased; it dissolves quickly in water, the dissolution time is 15-20 minutes, the plugging time is short, and it cannot meet the requirements of pressure drive operation.

[0010] Chinese patent application CN115838589A invented a temporary plugging agent of gel particles, which consists of 4% to 10% polyvinyl alcohol, 0.03% to 0.05% aldehyde cross-linking agent, 0.2% to 0.4% potential acid catalyst, and the balance is water. The temporary plugging agent has low plugging strength and a plugging pressure of 6.03MPa. It is suitable for temperatures of 90 to 120°C and a mineralization degree of ≤4×10 4 The pressure bearing capacity of the formation with a pressure drop of mg / L cannot meet the design requirements of the pressure drive process.

[0011] Chinese patent application CN115895617A discloses a fiber temporary plugging agent, which is a water-soluble temporary plugging agent. The temporary plugging agent includes 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 temporary plugging agent. The fiber temporary plugging agent has a good unblocking effect at a high temperature of 140-160°C, and the dissolution time is 20.5-23.8h. Its dissolution conditions and effects are suitable for high-temperature reservoir fracturing, but its breakthrough pressure is 10-18.7MPa, which is difficult to meet the pressure resistance and plugging time requirements of the pressure drive process design.

[0012] Chinese patent application CN109401739A invented a high temperature resistant shielding temporary plugging agent, which is an acid soluble temporary plugging agent. The components include 100 parts by weight of granular material, 5-20 parts by weight of elastic material, 5-20 parts by weight of filling material, 5-15 parts by weight of fiber material, and 1-5 parts by weight of micro-nano material. The temporary plugging agent can withstand temperatures up to 200°C, withstand pressure greater than 10MPa, and has an acid solubility greater than 80% in 15wt% hydrochloric acid. It has good temperature resistance, but its pressure bearing capacity is difficult to meet the pressure drive process design.

[0013] A degradable temporary plugging agent disclosed in Chinese patent application CN115960593A is in the shape of a knot, and is composed of 72-80 parts of a degradable resin, 12-20 parts of a modified polyglycolide, 1-5 parts of a nanoparticle toughening agent, 1-5 parts of a salt toughening agent, and 1-3 parts of a water-blocking agent. Although the temporary plugging agent improves the plugging time to a certain extent, it is mainly suitable for low-temperature reservoirs of 20-60°C, and the outer diameter of the knot is 13-18mm, which is usually suitable for blasthole plugging, and has poor applicability to temporary plugging in pressure-driven fractures in high-temperature reservoirs.

[0014] Chinese patent application CN115820232A discloses a biodegradable temporary plugging agent, the raw materials used are complex, including 60-80% by weight of polyethylene glycol, 15-25% by weight of polyvinyl alcohol, 0.5-2% by weight of zinc stearate, 0.5-2% by weight of 2-acrylamido-2-methylpropanesulfonic acid, 4-10% by weight of polybutylene succinate, 0.1-0.5% by weight of triacetin, 0.1-0.5% by weight of tributyl citrate, 0.3-0.7% by weight of polyethylene wax, 0.1-0.5% by weight of cationic starch, 0.1-0.3% by weight of sepiolite fiber, 1.0-3.0% by weight of calcium carbonate, 0.5-1.0% by weight of urotropine and 0.5-1.0% by weight of trimethylallyl ammonium chloride. It is suitable for reservoirs at 110-120℃ and can withstand a pressure of more than 50MPa. However, it has many components and is complex to prepare. It dissolves quickly at high temperatures. The higher the temperature, the faster it dissolves. The dissolution time is 7h above 100℃, and the plugging time is short, which cannot meet the design requirements of the pressure-driven process.

[0015] In summary, the existing temporary plugging agents are mainly used for fracturing and acidizing operations, and there are few temporary plugging agents used for pressure driving. Pressure driving operations are very different from fracturing operations and acidizing operations. Not only are the injection pressures high, but the operation cycle is long. Temporary plugging agents used for pressure driving are required to have not only strong pressure bearing capacity, but also long plugging time. Although there are many temporary plugging agent systems at present, it is still difficult to simultaneously meet the requirements of high temperature resistance, high salt resistance, strong pressure bearing capacity, and long plugging time. Summary of the invention

[0016] Purpose of the invention: In view of the above-mentioned deficiencies in the prior art, the present invention proposes a water suppression and anti-channeling temporary plugging system for pressure drive and its application to improve the effect of pressure drive water injection development of low permeability oil reservoirs.

[0017] Technical solution: A water suppression and anti-channeling temporary plugging system for pressure drive, which is composed of water-soluble fibers and soluble metal alloy particles in terms of mass percentage, wherein:

[0018] The water-soluble fiber accounts for 5-15%;

[0019] The soluble metal alloy particles account for 85-95%.

[0020] Furthermore, the soluble metal alloy particles are magnesium alloy soluble metal particles, the main components of which are composed of metal magnesium, metal aluminum and metal manganese, wherein:

[0021] The metal aluminum content is 5.0-10.0%, the metal manganese content is 0.1-0.5%, the carbon content is ≤0.05%, the metal nickel content is ≤0.01%, the metal calcium content is ≤0.005%, and the balance is metal magnesium.

[0022] Furthermore, the soluble metal alloy particles adopt a combination of various particle sizes, wherein the mass of soluble metal alloy particles of 20-40 mesh accounts for 30-40%, the mass of soluble metal alloy particles of 40-70 mesh accounts for 40-50%, and the remainder is soluble metal alloy particles of 70-100 mesh.

[0023] Furthermore, the apparent density of the soluble metal alloy particles is 0.15-0.40 g / cm 3 .

[0024] Furthermore, the water-soluble fiber is at least one of water-soluble polyvinyl alcohol fiber, seaweed fiber, carboxymethyl cellulose fiber, corn fiber and polyglycolic acid fiber, preferably water-soluble polyvinyl alcohol fiber.

[0025] Furthermore, the length of the water-soluble fiber is 4-12 mm, and the content of insoluble matter in water is ≤0.5 wt%.

[0026] The water suppression and anti-channeling temporary plugging system for pressure driving described in any one of the above items is used as a temporary plugging agent for pressure driving in low permeability oil reservoirs.

[0027] Furthermore, the specific steps of the above application are:

[0028] (1) Connecting the injection pipeline process, wherein: the injection pipeline process includes a liquid preparation tank equipped with a stirring facility and a high-pressure injection pump;

[0029] (2) Using a high-pressure injection pump to inject fluid through an injection well at a displacement greater than the formation absorption capacity, after the main fracture of the target formation is opened, the above-mentioned water suppression and anti-channeling temporary plugging system for pressure drive and an appropriate amount of fluid are added to a liquid preparation tank and stirred to form a water suppression and anti-channeling temporary plugging system solution for pressure drive with a certain injection concentration;

[0030] (3) injecting the water suppression and anti-channeling temporary plugging system solution obtained in step (2) into the formation fissures through the injection well using a high-pressure injection pump;

[0031] (4) When the injection pressure of the temporary plugging system solution for water suppression and anti-channeling reaches the difference between the maximum horizontal principal stress and the minimum horizontal principal stress of the target formation, the injection is stopped and the fluid is continuously injected to displace the temporary plugging system material to the end of the fracture, and then normal pressure drive is switched.

[0032] Furthermore, when the width of the main fracture of the target formation is less than 1.0 cm, the injection concentration of the water suppression and anti-channeling temporary plugging system solution for pressure drive is 0.8-1.5 wt %;

[0033] When the width of the main fracture of the target formation is ≥1.0 cm, the injection concentration of the water suppression and anti-channeling temporary plugging system solution for pressure drive is 1.0-2.0 wt %.

[0034] Furthermore, in step (2), a formulated amount of water-soluble fiber, a formulated amount of soluble metal alloy particles, and an appropriate amount of fluid are added to a liquid preparation tank for stirring and dispersion to obtain a water suppression and anti-channeling temporary plugging system solution for pressure drive with a certain injection concentration.

[0035] Furthermore, in step (3), the injection amount of the water suppression and anti-channeling temporary plugging system solution for pressure drive is greater than 1.5 times the volume of the column.

[0036] Furthermore, the fluid is one of water, surfactant aqueous solution and polymer aqueous solution.

[0037] Furthermore, the mass concentration of the surfactant aqueous solution is 0.001%-5%, and the surfactant is one of fatty alcohol polyoxyethylene ether, alkanolamide, alkylphenol polyoxyethylene ether, petroleum sulfonate, and betaine type surfactant.

[0038] Furthermore, the mass concentration of the polymer aqueous solution is 0.001%-2%, and the polymer is one of fructan, sodium alginate, polyacrylamide, and modified chitosan.

[0039] Furthermore, after the pressure drive in step (5) is completed, an acidic working fluid is injected into the target formation to remove the blockage, wherein:

[0040] The acid used in the acidic working fluid is one of hydrochloric acid, aminosulfonic acid, citric acid, acetic acid, formic acid, oxalic acid, phosphoric acid and organic phosphoric acid;

[0041] The pH value of the acidic working fluid is ≤6.

[0042] The water suppression and anti-channeling temporary plugging system for pressure drive disclosed in the present invention has the following characteristics: good dynamic suspension, temperature resistance ≥130℃, salt resistance ≥7×10 4mg / L, pressure difference resistance ≥45MPa, plugging time ≥20d, plugging rate ≥95%, the use of acidic degradation working fluid can achieve basically complete dissolution, and the damage rate of the residual liquid to the matrix is ​​<10%.

[0043] Beneficial effects: The beneficial effects of the present invention are as follows:

[0044] (1) Compared with conventional temporary plugging agents, the temporary plugging agent of the present invention has higher pressure difference resistance, stronger high temperature resistance, stronger temperature and salt resistance, longer effective plugging time, and can better meet the needs of long-term pressure drive operations;

[0045] (2) During the water injection and pressure driving process of the present invention, as the soluble metal alloy components gradually dissolve into powder particles with smaller particle sizes, the particles formed at the rear edge of the plugging section will continuously embed into the gaps of the temporary plugging material, and the powder particles formed at the front edge of the plugging section will enter deep small cracks or branch cracks, making the crack plugging more dense, the plugging rate higher, the plugging stability stronger, and further ensuring the plugging effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a curve chart showing the change in the plugging rate of the temporary plugging system for water suppression and anti-channeling under different plugging times.

[0047] Figure 2 It is a curve chart showing the change in the plugging rate of the temporary plugging system for water suppression and anti-channeling at different temperatures.

[0048] Figure 3 It is a curve chart showing the change in the plugging rate of the temporary plugging system for water suppression and anti-channeling under different mineralization degrees.

[0049] Figure 4 This is a graph showing the change of the dissolved residual rate of the pressure-driven water suppression and anti-channeling temporary plugging system over time. DETAILED DESCRIPTION

[0050] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods. Unless otherwise specified, the reagents and materials used can be obtained through commercial channels.

[0051] Example 1

[0052] A water suppression and anti-channeling temporary plugging system for pressure drive, which is composed of water-soluble fibers and soluble metal alloy particles in terms of mass percentage, wherein:

[0053] The water-soluble fiber accounts for 10%;

[0054] The soluble metal alloy particles account for 90%.

[0055] Furthermore, the soluble metal alloy particles are magnesium alloy soluble metal particles, the main components of which are composed of metal magnesium, metal aluminum and metal manganese, wherein:

[0056] The metal aluminum content is 8.2%, the metal manganese content is 0.23%, the carbon content is 0.03%, the metal nickel content is 0.005%, the metal calcium content is 0.003%, and the balance is metal magnesium.

[0057] The soluble metal alloy particles can gradually dissolve into powder particles with smaller particle size in water. The particles formed at the rear edge of the plugging section will continuously embed into the gaps of the temporary plugging material, and the powder particles formed at the front edge of the plugging section will enter deep small cracks or branch seams, thereby enhancing the plugging effect.

[0058] Furthermore, the soluble metal alloy particles adopt a combination of various particle sizes, wherein the mass proportion of soluble metal alloy particles of 20-40 mesh is 35%, the mass proportion of soluble metal alloy particles of 40-70 mesh is 45%, and the remainder is soluble metal alloy particles of 70-100 mesh.

[0059] Furthermore, the apparent density of the soluble metal alloy particles is 0.26 g / cm 3 .

[0060] Furthermore, the water-soluble fiber is water-soluble polyvinyl alcohol fiber.

[0061] Furthermore, the length of the water-soluble fiber is 6 mm, and the content of insoluble matter in water is ≤0.5 wt %.

[0062] The above-mentioned temporary plugging system for water suppression and anti-channeling for pressure drive is used as a temporary plugging agent for pressure drive in low permeability oil reservoirs.

[0063] The injection well A of a low permeability oil reservoir in Shengli Oilfield has an injection pressure of 35.3 MPa before temporary plugging. The water suppression and anti-channeling temporary plugging system for pressure drive of Example 1 is used as a temporary plugging agent for pressure drive.

[0064] Furthermore, the specific steps of the above application are:

[0065] (1) Connecting the injection pipeline process, wherein: the injection pipeline process includes a liquid preparation tank equipped with a stirring facility and a high-pressure injection pump;

[0066] (2) Using a high-pressure injection pump to inject fluid through an injection well at a displacement greater than the formation absorption capacity, after the main fracture of the target formation is opened, the above-mentioned water suppression and anti-channeling temporary plugging system for pressure drive and an appropriate amount of fluid are added to a liquid preparation tank and stirred to form a water suppression and anti-channeling temporary plugging system solution for pressure drive with a certain injection concentration;

[0067] (3) injecting the water suppression and anti-channeling temporary plugging system solution obtained in step (2) into the formation fissures through the injection well using a high-pressure injection pump;

[0068] (4) When the injection pressure of the temporary plugging system solution for water suppression and anti-channeling reaches the difference between the maximum horizontal principal stress and the minimum horizontal principal stress of the target formation, the injection is stopped and the fluid is continuously injected to displace the temporary plugging system material to the end of the fracture, and then normal pressure drive is switched.

[0069] Furthermore, the width of the main fracture of the target formation is 0.8 cm, and the injection concentration of the water suppression and anti-channeling temporary plugging system solution for pressure drive is 0.8 wt %.

[0070] Furthermore, in step (2), a formulated amount of water-soluble fiber, a formulated amount of soluble metal alloy particles, and an appropriate amount of fluid are added to a liquid preparation tank for stirring and dispersion to obtain a water suppression and anti-channeling temporary plugging system solution for pressure drive with a certain injection concentration.

[0071] Furthermore, in step (3), the injection amount of the water suppression and anti-channeling temporary plugging system solution for pressure drive is greater than 1.5 times the volume of the column.

[0072] Furthermore, the fluid is water.

[0073] Furthermore, after the pressure drive in step (5) is completed, an acidic working fluid is injected into the target formation to remove the blockage, wherein:

[0074] The acid used in the acidic working fluid is hydrochloric acid;

[0075] The pH value of the acidic working solution is ≤6.

[0076] After testing, the injection pressure of injection well A in a low-permeability oil reservoir in Shengli Oilfield increased from 35.3MPa to 36.9 before and after temporary plugging, and the pressure increased by 1.6MPa, indicating that an effective plugging was formed in the cracks.

[0077] The water suppression and anti-channeling temporary plugging system for pressure drive of Example 1 was mixed with an appropriate amount of water to obtain a water suppression and anti-channeling temporary plugging system solution for pressure drive with an injection concentration of 0.8wt%. The core fracture plugging rate of the water suppression and anti-channeling temporary plugging system solution for pressure drive at different plugging times was tested by core displacement experiments. The results are as follows Figure 1 As shown, the blocking rate is ≥98%.

[0078] Example 2

[0079] A water suppression and anti-channeling temporary plugging system for pressure drive, which is composed of water-soluble fibers and soluble metal alloy particles in terms of mass percentage, wherein:

[0080] The water-soluble fiber accounts for 5%;

[0081] The soluble metal alloy particles account for 95%.

[0082] Furthermore, the soluble metal alloy particles are magnesium alloy soluble metal particles, the main components of which are composed of metal magnesium, metal aluminum and metal manganese, wherein:

[0083] The metal aluminum content is 5.0%, the metal manganese content is 0.1%, the carbon content is 0.01%, the metal nickel content is 0.001%, the metal calcium content is 0.001%, and the balance is metal magnesium.

[0084] The soluble metal alloy particles can gradually dissolve into powder particles with smaller particle size in water. The particles formed at the rear edge of the plugging section will continuously embed into the gaps of the temporary plugging material, and the powder particles formed at the front edge of the plugging section will enter deep small cracks or branch seams, thereby enhancing the plugging effect.

[0085] Furthermore, the soluble metal alloy particles adopt a combination of various particle sizes, wherein the mass of soluble metal alloy particles of 20-40 mesh accounts for 30%, the mass of soluble metal alloy particles of 40-70 mesh accounts for 40%, and the remainder is soluble metal alloy particles of 70-100 mesh.

[0086] Furthermore, the apparent density of the soluble metal alloy particles is 0.15 g / cm 3 .

[0087] Furthermore, the water-soluble fiber is seaweed fiber.

[0088] Furthermore, the length of the water-soluble fiber is 4 mm, and the content of insoluble matter in water is ≤0.5 wt %.

[0089] The above-mentioned temporary plugging system for water suppression and anti-channeling for pressure drive is used as a temporary plugging agent for pressure drive in low permeability oil reservoirs.

[0090] The injection well B of a low permeability oil reservoir in Shengli Oilfield has an injection pressure of 40.2 MPa before temporary plugging. The water suppression and anti-channeling temporary plugging system for pressure driving of Example 2 is used as a temporary plugging agent for pressure driving.

[0091] Furthermore, the specific steps of the above application are:

[0092] (1) Connecting the injection pipeline process, wherein: the injection pipeline process includes a liquid preparation tank equipped with a stirring facility and a high-pressure injection pump;

[0093] (2) Using a high-pressure injection pump to inject fluid through an injection well at a displacement greater than the formation absorption capacity, after the main fracture of the target formation is opened, the above-mentioned water suppression and anti-channeling temporary plugging system for pressure drive and an appropriate amount of fluid are added to a liquid preparation tank and stirred to form a water suppression and anti-channeling temporary plugging system solution for pressure drive with a certain injection concentration;

[0094] (3) injecting the water suppression and anti-channeling temporary plugging system solution obtained in step (2) into the formation fissures through the injection well using a high-pressure injection pump;

[0095] (4) When the injection pressure of the temporary plugging system solution for water suppression and anti-channeling reaches the difference between the maximum horizontal principal stress and the minimum horizontal principal stress of the target formation, the injection is stopped and the fluid is continuously injected to displace the temporary plugging system material to the end of the fracture, and then normal pressure drive is switched.

[0096] Furthermore, the width of the main fracture of the target formation is 0.89 cm, and the injection concentration of the water suppression and anti-channeling temporary plugging system solution for pressure drive is 1.5 wt %.

[0097] Furthermore, in step (2), a formulated amount of water-soluble fiber, a formulated amount of soluble metal alloy particles, and an appropriate amount of fluid are added to a liquid preparation tank for stirring and dispersion to obtain a water suppression and anti-channeling temporary plugging system solution for pressure drive with a certain injection concentration.

[0098] Furthermore, in step (3), the injection amount of the water suppression and anti-channeling temporary plugging system solution for pressure drive is greater than 1.5 times the volume of the column.

[0099] Furthermore, the fluid is an aqueous solution of a surfactant.

[0100] Furthermore, the mass concentration of the surfactant aqueous solution is 3% fatty alcohol polyoxyethylene ether aqueous solution. In another embodiment, the mass concentration of the surfactant aqueous solution is 0.001%, and the surfactant is alkanolamide. In another embodiment, the mass concentration of the surfactant aqueous solution is 5%, and the surfactant is alkylphenol polyoxyethylene ether. In another embodiment, the mass concentration of the surfactant aqueous solution is 1%, and the surfactant is petroleum sulfonate. In another embodiment, the mass concentration of the surfactant aqueous solution is 4%, and the surfactant is a betaine type surfactant.

[0101] Furthermore, after the pressure drive in step (5) is completed, an acidic working fluid is injected into the target formation to remove the blockage, wherein:

[0102] The acid used in the acidic working fluid is aminosulfonic acid;

[0103] The pH value of the acidic working fluid is ≤6.

[0104] After testing, the injection pressure of injection well B in a low-permeability oil reservoir in Shengli Oilfield increased from 40.2MPa to 42.0 before and after temporary plugging, with the pressure increased by 1.8MPa, and an effective seal was formed in the surface cracks.

[0105] The water suppression and anti-channeling temporary plugging system for pressure drive of Example 2 was mixed evenly with an appropriate amount of fatty alcohol polyoxyethylene ether aqueous solution with a mass concentration of 3% to obtain a water suppression and anti-channeling temporary plugging system solution for pressure drive with an injection concentration of 1.5wt%. The core fracture plugging rate of the water suppression and anti-channeling temporary plugging system solution for pressure drive was tested under different temperature conditions (normal temperature -130°C) by core displacement experiments. The results are as follows: Figure 2 As shown, the plugging rate is ≥96%.

[0106] Example 3

[0107] A water suppression and anti-channeling temporary plugging system for pressure drive, which is composed of water-soluble fibers and soluble metal alloy particles in terms of mass percentage, wherein:

[0108] The water-soluble fiber accounts for 15%;

[0109] The soluble metal alloy particles account for 85%.

[0110] Furthermore, the soluble metal alloy particles are magnesium alloy soluble metal particles, the main components of which are composed of metal magnesium, metal aluminum and metal manganese, wherein:

[0111] The metal aluminum content is 10.0%, the metal manganese content is 0.5%, the carbon content is 0.045%, the metal nickel content is 0.01%, the metal calcium content is 0.005%, and the balance is metal magnesium.

[0112] The soluble metal alloy particles can gradually dissolve into powder particles with smaller particle size in water. The particles formed at the rear edge of the plugging section will continuously embed into the gaps of the temporary plugging material, and the powder particles formed at the front edge of the plugging section will enter deep small cracks or branch seams, thereby enhancing the plugging effect.

[0113] Furthermore, the soluble metal alloy particles adopt a combination of various particle sizes, wherein the mass of soluble metal alloy particles of 20-40 mesh accounts for 40%, the mass of soluble metal alloy particles of 40-70 mesh accounts for 50%, and the remainder is soluble metal alloy particles of 70-100 mesh.

[0114] Furthermore, the apparent density of the soluble metal alloy particles is 0.40 g / cm 3 .

[0115] Furthermore, the water-soluble fiber is carboxymethyl cellulose fiber.

[0116] Furthermore, the length of the water-soluble fiber is 12 mm, and the content of insoluble matter in water is ≤0.5 wt %.

[0117] The above-mentioned temporary plugging system for water suppression and anti-channeling for pressure drive is used as a temporary plugging agent for pressure drive in low permeability oil reservoirs.

[0118] The injection well C of a low permeability oil reservoir in Shengli Oilfield has an injection pressure of 38.2 MPa before temporary plugging. The water suppression and anti-channeling temporary plugging system for pressure driving of Example 3 is used as a temporary plugging agent for pressure driving.

[0119] Furthermore, the specific steps of the above application are:

[0120] (1) Connecting the injection pipeline process, wherein: the injection pipeline process includes a liquid preparation tank equipped with a stirring facility and a high-pressure injection pump;

[0121] (2) Using a high-pressure injection pump to inject fluid through an injection well at a displacement greater than the formation absorption capacity, after the main fracture of the target formation is opened, the above-mentioned water suppression and anti-channeling temporary plugging system for pressure drive and an appropriate amount of fluid are added to a liquid preparation tank and stirred to form a water suppression and anti-channeling temporary plugging system solution for pressure drive with a certain injection concentration;

[0122] (3) injecting the water suppression and anti-channeling temporary plugging system solution obtained in step (2) into the formation fissures through the injection well using a high-pressure injection pump;

[0123] (4) When the injection pressure of the temporary plugging system solution for water suppression and anti-channeling reaches the difference between the maximum horizontal principal stress and the minimum horizontal principal stress of the target formation, the injection is stopped and the fluid is continuously injected to displace the temporary plugging system material to the end of the fracture, and then normal pressure drive is switched.

[0124] Furthermore, the width of the main fracture of the target formation is 1.2 cm, and the injection concentration of the water suppression and anti-channeling temporary plugging system solution for pressure drive is 1.0 wt %.

[0125] Furthermore, in step (2), a formulated amount of water-soluble fiber, a formulated amount of soluble metal alloy particles, and an appropriate amount of fluid are added to a liquid preparation tank for stirring and dispersion to obtain a water suppression and anti-channeling temporary plugging system solution for pressure drive with a certain injection concentration.

[0126] Furthermore, in step (3), the injection amount of the water suppression and anti-channeling temporary plugging system solution for pressure drive is greater than 1.5 times the volume of the column.

[0127] Furthermore, the fluid is a polymer aqueous solution.

[0128] Furthermore, the mass concentration of the polymer aqueous solution is 1%, and the polymer is fructan. In another embodiment, the mass concentration of the polymer aqueous solution is 0.001%, and the polymer is sodium alginate. In another embodiment, the mass concentration of the polymer aqueous solution is 2%, and the polymer is polyacrylamide. In another embodiment, the mass concentration of the polymer aqueous solution is 0.5%, and the polymer is modified chitosan.

[0129] Furthermore, after the pressure drive in step (5) is completed, an acidic working fluid is injected into the target formation to remove the blockage, wherein:

[0130] The acid used in the acidic working fluid is citric acid;

[0131] The pH value of the acidic working fluid is ≤6.

[0132] After testing, the injection pressure of injection well C in a low-permeability oil reservoir in Shengli Oilfield increased from 38.2MPa to 40.1 before and after temporary plugging, with a pressure increase of 1.9MPa, and an effective plugging was formed in the surface cracks.

[0133] The water suppression and anti-channeling temporary plugging system for pressure driving of Example 3 was uniformly mixed with a 1% fructan aqueous solution to prepare a 1.0 wt% water suppression and anti-channeling temporary plugging system for pressure driving solution. The core displacement experiment was conducted to test the plugging rate of the water suppression and anti-channeling temporary plugging system for pressure driving solution under different salinities. The results are as follows: Figure 3 As shown, the blocking rate is ≥98%.

[0134] Example 4

[0135] A water suppression and anti-channeling temporary plugging system for pressure drive, which is composed of water-soluble fibers and soluble metal alloy particles in terms of mass percentage, wherein:

[0136] The water-soluble fiber accounts for 8%;

[0137] The soluble metal alloy particles accounted for 92%.

[0138] Furthermore, the soluble metal alloy particles are magnesium alloy soluble metal particles, the main components of which are composed of metal magnesium, metal aluminum and metal manganese, wherein:

[0139] The metal aluminum content is 6%, the metal manganese content is 0.3%, the carbon content is 0.03%, the metal nickel content is 0.01%, the metal calcium content is 0.005%, and the balance is metal magnesium.

[0140] The soluble metal alloy particles can gradually dissolve into powder particles with smaller particle size in water. The particles formed at the rear edge of the plugging section will continuously embed into the gaps of the temporary plugging material, and the powder particles formed at the front edge of the plugging section will enter deep small cracks or branch seams, thereby enhancing the plugging effect.

[0141] Furthermore, the soluble metal alloy particles adopt a combination of various particle sizes, among which the mass proportion of soluble metal alloy particles of 20-40 mesh is 32%, the mass proportion of soluble metal alloy particles of 40-70 mesh is 42%, and the remainder is soluble metal alloy particles of 70-100 mesh.

[0142] Furthermore, the apparent density of the soluble metal alloy particles is 0.34 g / cm 3 .

[0143] Furthermore, the water-soluble fiber is corn fiber. In another embodiment, the water-soluble fiber is polyglycolic acid fiber. In another embodiment, the water-soluble fiber is a mixture of water-soluble polyvinyl alcohol fiber, seaweed fiber, carboxymethyl cellulose fiber, corn fiber and polyglycolic acid fiber in equal weight ratio.

[0144] Furthermore, the length of the water-soluble fiber is 6 mm, and the content of insoluble matter in water is ≤0.5 wt %.

[0145] The above-mentioned temporary plugging system for water suppression and anti-channeling for pressure drive is used as a temporary plugging agent for pressure drive in low permeability oil reservoirs.

[0146] The injection well D of a low permeability oil reservoir in Shengli Oilfield has an injection pressure of 41.3 MPa before temporary plugging. The water suppression and anti-channeling temporary plugging system for pressure driving of Example 4 is used as a temporary plugging agent for pressure driving.

[0147] Furthermore, the specific steps of the above application are:

[0148] (1) Connecting the injection pipeline process, wherein: the injection pipeline process includes a liquid preparation tank equipped with a stirring facility and a high-pressure injection pump;

[0149] (2) Using a high-pressure injection pump to inject fluid through an injection well at a displacement greater than the formation absorption capacity, after the main fracture of the target formation is opened, the above-mentioned water suppression and anti-channeling temporary plugging system for pressure drive and an appropriate amount of fluid are added to a liquid preparation tank and stirred to form a water suppression and anti-channeling temporary plugging system solution for pressure drive with a certain injection concentration;

[0150] (3) injecting the water suppression and anti-channeling temporary plugging system solution obtained in step (2) into the formation fissures through the injection well using a high-pressure injection pump;

[0151] (4) When the injection pressure of the temporary plugging system solution for water suppression and anti-channeling reaches the difference between the maximum horizontal principal stress and the minimum horizontal principal stress of the target formation, the injection is stopped and the fluid is continuously injected to displace the temporary plugging system material to the end of the fracture, and then normal pressure drive is switched.

[0152] Furthermore, the width of the main fracture of the target formation is 2.0 cm, and the injection concentration of the water suppression and anti-channeling temporary plugging system solution for pressure drive is 2.0 wt %.

[0153] Furthermore, in step (2), a formulated amount of water-soluble fiber, a formulated amount of soluble metal alloy particles, and an appropriate amount of fluid are added to a liquid preparation tank for stirring and dispersion to obtain a water suppression and anti-channeling temporary plugging system solution for pressure drive with a certain injection concentration.

[0154] Furthermore, in step (3), the injection amount of the water suppression and anti-channeling temporary plugging system solution for pressure drive is greater than 1.5 times the volume of the column.

[0155] Furthermore, the fluid is water.

[0156] Furthermore, after the pressure drive in step (5) is completed, an acidic working fluid is injected into the target formation to remove the blockage, wherein:

[0157] The acid used in the acidic working solution is acetic acid; the pH value of the acidic working solution is ≤6. In another embodiment, the acid used in the acidic working solution is formic acid. In another embodiment, the acid used in the acidic working solution is oxalic acid. In another embodiment, the acid used in the acidic working solution is phosphoric acid. In another embodiment, the acid used in the acidic working solution is organic phosphoric acid.

[0158] After testing, the injection pressure of water injection well D in a low-permeability oil reservoir in Shengli Oilfield increased from 41.3MPa to 43.5MPa before and after temporary plugging, with a pressure increase of 2.2MPa, and an effective seal was formed in the surface cracks.

[0159] A certain amount of the temporary plugging system for water suppression and anti-channeling of Example 4 was placed in water at 110-130°C and pH 3 for residual rate test. After 5 hours, the temporary plugging system material was basically completely dissolved. The results are as follows: Figure 4 As shown, the dissolution rate was >99%.

[0160] Performance Standards:

[0161] Test Example 1

[0162] The water suppression and anti-channeling temporary plugging system for pressure drive of Example 4 was taken, and water was added to prepare an aqueous solution of the water suppression and anti-channeling temporary plugging system for pressure drive with a mass concentration of 1%. The core displacement device was used to carry out the core permeability damage evaluation, and the results showed that the average damage rate was 8.12%. Compared with the clean water core damage evaluation results, the liquid damage rate of the pressure drive water suppression and anti-channeling temporary plugging system after dissolution increased by about 2.73% to the core permeability.

[0163] Table 1. Results of damage assessment of clean water cores

[0164]

[0165] Table 2 Evaluation results of liquid core damage after dissolution of the temporary plugging system for water suppression and anti-channeling in pressure drive

[0166]

[0167] Test Example 2

[0168] Equipped with gel-type temporary plugging agents commonly used in oil fields and fiber-type temporary plugging agents (PVA) for oil fields.

[0169] High temperature and high salt core displacement test: For Example 1, Example 2, Example 3, the commonly used gel temporary plugging agent in oil fields and the fiber temporary plugging agent (PVA) in oil fields, the fracture plugging rates were compared after displacement for 3 days at 80°C and a constant pressure difference of 20 MPa.

[0170] Table 3 Plugging rate test results

[0171]

[0172]

[0173] According to the core displacement effect test results, after 3 days of displacement at 80°C and a constant pressure of 20 MPa, the crack plugging rate of the water suppression and anti-channeling temporary plugging system suitable for pressure drive in low permeability oil reservoirs of the present invention is significantly higher than the crack plugging rate of the commonly used gel-type temporary plugging agent in oil fields and the fiber temporary plugging agent (PVA) used in oil fields.

[0174] Test Example 3

[0175] High-temperature and high-salt core displacement test: For Example 1, Example 2, Example 3, the commonly used gel-type temporary plugging agent in oil fields and the fiber-type temporary plugging agent (PVA) for oil fields, the injection pressure was gradually increased from 5MPa to 45MPa in an 80°C environment to observe whether the temporary plugging section in the crack was broken through, and to test its pressure difference resistance performance.

[0176] Table 4 Compressive strength test results

[0177]

[0178] The core displacement effect test results show that the pressure bearing capacity of the water suppression and anti-channeling temporary plugging system for pressure drive in low permeability oil reservoirs of the present invention is significantly higher than the pressure bearing capacity of the commonly used gel-type temporary plugging agent in oil fields and the fiber temporary plugging agent (PVA) for oil fields.

[0179] In summary, the water suppression and anti-channeling temporary plugging system for pressure drive disclosed in the present invention has good dynamic suspension and temperature resistance of ≥130℃ (see Figure 2 ), salt tolerance ≥7×10 4 mg / L (see Figure 3 ), plugging time ≥ 20d (see Figure 1 ), the acidic degradation working fluid can achieve almost complete dissolution, and the damage rate of the residual liquid to the matrix is ​​less than 10%.

[0180] The above describes the embodiments of the present invention in detail. However, the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A water suppression and anti-channeling temporary plugging system for pressure drive, characterized in that: Measured by mass percentage, it is composed of water-soluble fibers and soluble metal alloy particles, of which: The water-soluble fiber accounts for 5-15%; The soluble metal alloy particles account for 85-95%.

2. A water suppression and anti-channeling temporary plugging system for pressure drive according to claim 1, characterized in that: The soluble metal alloy particles are magnesium alloy soluble metal particles, the main components of which are composed of metal magnesium, metal aluminum and metal manganese, wherein: The metal aluminum content is 5.0-10.0%, the metal manganese content is 0.1-0.5%, the carbon content is ≤0.05%, the metal nickel content is ≤0.01%, the metal calcium content is ≤0.005%, and the balance is metal magnesium.

3. A water suppression and anti-channeling temporary plugging system for pressure drive according to claim 1, characterized in that: The soluble metal alloy particles are a combination of various particle sizes, wherein the mass of soluble metal alloy particles of 20-40 mesh accounts for 30-40%, the mass of soluble metal alloy particles of 40-70 mesh accounts for 40-50%, and the remainder is soluble metal alloy particles of 70-100 mesh.

4. A water suppression and anti-channeling temporary plugging system for pressure drive according to claim 1, characterized in that: The apparent density of the soluble metal alloy particles is 0.15-0.40 g / cm 3 .

5. A water suppression and anti-channeling temporary plugging system for pressure drive according to claim 1, characterized in that: The water-soluble fiber is at least one of water-soluble polyvinyl alcohol fiber, seaweed fiber, carboxymethyl cellulose fiber, corn fiber and polyglycolic acid fiber, preferably water-soluble polyvinyl alcohol fiber.

6. A water suppression and anti-channeling temporary plugging system for pressure drive according to claim 1, characterized in that: The length of the water-soluble fiber is 4-12 mm, and the content of insoluble matter in water is ≤0.5 wt %.

7. Use of the water suppression and anti-channeling temporary plugging system for pressure drive according to any one of claims 1 to 6 as a temporary plugging agent for pressure drive in low permeability oil reservoirs.

8. The use according to claim 7, characterized in that The specific steps of the above application are: (1) Connecting the injection pipeline process, wherein: the injection pipeline process includes a liquid preparation tank equipped with a stirring facility and a high-pressure injection pump; (2) Using a high-pressure injection pump to inject fluid through an injection well at a displacement greater than the formation absorption capacity, after the main fracture of the target formation is opened, the above-mentioned water suppression and anti-channeling temporary plugging system for pressure drive and an appropriate amount of fluid are added to a liquid preparation tank and stirred to form a water suppression and anti-channeling temporary plugging system solution for pressure drive with a certain injection concentration; (3) injecting the water suppression and anti-channeling temporary plugging system solution obtained in step (2) into the formation fissures through the injection well using a high-pressure injection pump; (4) When the injection pressure of the temporary plugging system solution for water suppression and anti-channeling reaches the difference between the maximum horizontal principal stress and the minimum horizontal principal stress of the target formation, the injection is stopped and the fluid is continuously injected to displace the temporary plugging system material to the end of the fracture, and then normal pressure drive is switched.

9. The use according to claim 8, characterized in that When the width of the main fracture of the target formation is less than 1.0 cm, the injection concentration of the water suppression and anti-channeling temporary plugging system solution for pressure drive is 0.8-1.5wt%; When the width of the main fracture of the target formation is ≥1.0 cm, the injection concentration of the water suppression and anti-channeling temporary plugging system solution for pressure drive is 1.0-2.0 wt %.

10. The use according to claim 8, characterized in that In step (2), a formulated amount of water-soluble fiber, a formulated amount of soluble metal alloy particles, and an appropriate amount of fluid are added to a liquid preparation tank for stirring and dispersion to obtain a water suppression and anti-channeling temporary plugging system solution for pressure drive with a certain injection concentration.

11. The use according to claim 8, characterized in that In step (3), the injection amount of the water suppression and anti-channeling temporary plugging system solution for pressure drive is greater than 1.5 times the volume of the column.

12. The use according to claim 8, characterized in that The fluid is one of water, surfactant aqueous solution and polymer aqueous solution.

13. The use according to claim 12, characterized in that The mass concentration of the surfactant aqueous solution is 0.001%-5%, and the surfactant is one of fatty alcohol polyoxyethylene ether, alkanolamide, alkylphenol polyoxyethylene ether, petroleum sulfonate, and betaine type surfactant.

14. The use according to claim 12, characterized in that The mass concentration of the polymer aqueous solution is 0.001%-2%, and the polymer is one of fructan, sodium alginate, polyacrylamide and modified chitosan.

15. The use according to claim 8, characterized in that The method further comprises injecting an acidic working fluid into the target formation to remove the blockage after the pressure drive of step (5) is completed, wherein: The acid used in the acidic working fluid is one of hydrochloric acid, aminosulfonic acid, citric acid, acetic acid, formic acid, oxalic acid, phosphoric acid and organic phosphoric acid; The pH value of the acidic working solution is ≤6.

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